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3.%09What would be the expected result in this experiment if only ligroin (as opposed to ligroin followed by a ligroin-ether mixture) were used as the eluent in this experiment? Explain your answer. 0Tue Nov 18
2.%09Predict the order of elution of a mixture of cyclohexane (an alkane), butyl acetate (an ester), benzoic acid (a carboxylic acid), methyl t-butyl ether (an ether), and cyclohexanol (an alcohol).from an alumina column. 1Thu Nov 20
explain the observed differences in rf values for the three known amino acids 0Thu Nov 6
Why is a mixture of 6:4 hexanes and acetone used(and not hexanes) to elute the yellow fraction of fluorenone in the column chromatography experiment? 0Thu Nov 6
You have recrystallized ferrocene by the two-solvent method (acetone-water). Based on the following solubility test results for ferrocene, suggest (i) another pair of solvents that may be used in the two-solvent method and (ii) a solvent that may be used for the single solvent method 0Mon Nov 3
Tlc solvent of too high polarity 0Mon Nov 3
4-HYDROXY PIPERIDINE STANDARD TESTING PROCEDURE 0Mon Nov 3
how many atoms are in a sulfate ion? 0Thu Oct 30
difference between post precipation and co precipation 0Sat Oct 25
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2.%09If two different substances have the same or nearly the same Rf values, it is difficult to separate (resolve) these materials in a mixture. How could this experiment be changed to separate such a mixture? 0Mon Oct 20
HPLC 0Mon Oct 20
supply from stock 1-Acetyl-4-Boc-amino-piperidine %7C CAS: 283167-28-2 1Sun Oct 19
supply from stock methyl 1-(2-phenylethyl)-4-oxo-piperidine-3-carboxylate %7C CAS: 66670-11-9 1Sun Oct 19
supply from stock 4-Amino-1-cyclopropylpiperidine %7C CAS: 62813-02-9 1Sun Oct 19
supply from stock 1-Propyl-3-piperidinol %7C CAS: 27361-79-1 1Sun Oct 19
supply from stock 3-(Methylsulfonyloxy)piperidine-1-carboxylic acid tert-butyl ester %7C CAS: 129888-60-4 1Sun Oct 19
supply from stock Methyl 4-oxo-3-piperidinecarboxylate hydrochloride %7C CAS: 71486-53-8 1Sun Oct 19
supply from stock 1-Benzyl-3-ethoxycarbonyl-4-piperidone %7C CAS: 41276-30-6 1Sun Oct 19
supply from stock Methyl 1-benzyl-4-oxo-3-piperidinecarboxylate %7C CAS: 57611-47-9 1Sun Oct 19
supply from stock Oxazole-4-carboxylic acid %7C CAS: 23012-13-7 1Sun Oct 19
supply from stock 1-(Ethoxycarbonyl)piperidine-4-carboxylic acid %7C CAS: 118133-15-6 1Sun Oct 19
supply from stock N-Phenyl-4-piperidone %7C CAS: 19125-34-9 1Sun Oct 19
supply from stock N-Boc-3-carboethoxy-4-piperidone %7C CAS: 98977-34-5 1Sun Oct 19
supply from stock 4-Benzyloxycarbonylamino-N-Boc-piperdine %7C CAS: 220394-97-8 1Sun Oct 19
supply from stock N-Acetyl-4-piperidone %7C CAS: 32161-06-1 1Sun Oct 19
supply from stock Methyl 4-oxo-3-piperidinecarboxylate hydrochloride %7C CAS: 56026-52-9 1Sun Oct 19
supply from stock N-Isobutyl-4-piperidone %7C CAS: 72544-16-2 1Sun Oct 19
supply from stock 1-Fmoc-piperidine-4-carboxylic acid %7C CAS: 148928-15-8 1Sun Oct 19
supply from stock Methyl N-CBZ-Piperidine-4-carboxylate %7C CAS: 138163-07-2 1Sun Oct 19
4.%09If two different substances have the same or nearly the same Rf values, it is difficult to separate (resolve) these materials in a mixture. How could this experiment be changed to separate such a mixture? 0Sun Oct 19
how can I determine L-theanine concentration in beverage with uv/vis? 0Tue Sep 30
Why is it important to trace the solvent line as soon as the TLC plate comes out of the chamber? 0Mon Sep 29
supply from stock 1-Benzyl-3-carbomethoxy-4-piperidone hydrochloride | CAS: 3939-01-3 0Sat Sep 27
supply from stock 1-Cyclopropylpiperidin-4-one | CAS: 62813-01-8 0Sat Sep 27
supply from stock 1-Boc-3-Methyl-3-hydroxypiperidine | CAS: 1104083-27-3 0Sat Sep 27
Supply from stock 1-Benzyloxycarbonyl-4-tert-butoxycarbonylaminopiperidine | CAS: 159874-20-1 0Sat Sep 27
supply from stock 3-Aminopiperidine dihydrochloride | CAS: 138060-07-8 0Sat Sep 27
supply from stock N-Boc-4-MethanesulfonyloxyMethyl-piperidine | CAS: 161975-39-9 0Sat Sep 27
supply from stock 1-(Methoxycarbonyl)piperidine-4-carboxylic acid | CAS: 197585-42-5 0Sat Sep 27
supply from stock 1-Benzyl-4-Methylpiperidin-4-ol | CAS: 3970-66-9 0Sat Sep 27
supply from stock 1-Cyclopropyl-piperidin-4-ol | CAS: 851847-62-6 0Sat Sep 27
supply from stock N-Phenyl-1-(2-phenethyl)piperidin-4-amine | CAS: 21409-26-7 0Sat Sep 27
supply from stock N-Phenyl-1-(2-phenethyl)piperidin-4-amine %7C CAS: 21409-26-7 1Sat Sep 27
supply from stock 1,3-Dimethyl-4-piperidinone %7C CAS: 4629-80-5 1Sat Sep 27
Supply from stock 1-Benzyloxycarbonyl-4-tert-butoxycarbonylaminopiperidine %7C CAS: 159874-20-1 1Sat Sep 27
supply from stock N-Fmoc-4-piperidone %7C CAS: 204376-55-6 1Sat Sep 27
supply from stock N-Boc-4-MethanesulfonyloxyMethyl-piperidine %7C CAS: 161975-39-9 1Sat Sep 27
supply from stock 3-Aminopiperidine %7C CAS: 54012-73-6 1Sat Sep 27
supply from stock N-BOC-4-(4-toluenesulfonyloxymethyl)piperidine %7C CAS: 166815-96-9 1Sat Sep 27
supply from stock 1-Benzyl-3-carbethoxy-4-piperidone hydrochloride %7C CAS: 1454-53-1 1Sat Sep 27
supply from stock 1-Benzyl-3-carbomethoxy-4-piperidone hydrochloride %7C CAS: 3939-01-3 1Sat Sep 27
supply from stock tert-Butyl 4-(hydroxyimino)piperidine-1-carboxylate %7C CAS: 150008-24-5 1Sat Sep 27
supply from stock 1-Cyclopropyl-piperidin-4-ol %7C CAS: 851847-62-6 1Sat Sep 27
supply from stock 3-Methyl-4-piperidone %7C CAS: 5773-58-0 1Sat Sep 27
supply from stock tert-Butyl 3-methyl-4-oxopiperidine-1-carboxylate %7C CAS: 181269-69-2 1Sat Sep 27
supply from stock 1-Benzyl-3-methyl-4-piperidone | CAS: 34737-89-8 1Sat Sep 27
supply from stock 1-Benzyl-3-methyl-4-piperidone %7C CAS: 34737-89-8 1Sat Sep 27
supply from stock 1-Cyclopropylpiperidin-4-one %7C CAS: 62813-01-8 2Sat Sep 27
supply from stock Methyl 4-oxazolecarboxylate %7C CAS: 170487-38-4 1Sat Sep 27
supply from stock 1-(Methoxycarbonyl)piperidine-4-carboxylic acid %7C CAS: 197585-42-5 1Sat Sep 27
supply from stock 1-Benzyl-4-Methylpiperidin-4-ol %7C CAS: 3970-66-9 1Sat Sep 27
supply from stock 1-Boc-3-Methyl-3-hydroxypiperidine %7C CAS: 1104083-27-3 1Sat Sep 27
supply from stock 3-Aminopiperidine dihydrochloride %7C CAS: 138060-07-8 1Sat Sep 27
is hexane suitable for a single solvent recrystallization of 4-bromoacetanilide? 0Fri Sep 26
supply from stock 4-Formylpiperidine-1-carboxylic acid benzyl ester | CAS: 138163-08-3 1Sat Sep 27
supply from stock 1-Isopropyl-3-piperidinol | CAS: 3554-62-9 1Sat Sep 27
supply from stock N-Boc-4-Piperidinecarboxamide | CAS: 91419-48-6 1Sat Sep 27
supply from stock N-Benzyl-3-pyrrolidinol | CAS: 775-15-5 1Sat Sep 27
supply from stock 4-Amino-1-ethylpiperidine | CAS: 50534-45-7 1Sat Sep 27
supply from stock 1-Ethyl-4-piperidone | CAS: 91419-48-6 2Sat Sep 27
supply from stock N-Boc-4-Piperidinecarboxamide %7C CAS: 91419-48-6 1Wed Sep 24
supply from stock 1-Boc-piperidine-4-carboxylhydrazide %7C CAS: 187834-88-4 1Wed Sep 24
supply from stock 4-Amino-1-ethylpiperidine %7C CAS: 50534-45-7 1Wed Sep 24
supply from stock 1-Ethyl-4-piperidone %7C CAS: 91419-48-6 1Wed Sep 24
supply from stock 1-(3-Methoxypropyl)-4-piperidinol %7C CAS: 1225518-03-5 1Wed Sep 24
supply from stock 1-Isopropyl-3-piperidinol %7C CAS: 3554-62-9 1Wed Sep 24
supply from stock 1-Benzyl-4-piperidinecarboxylic acid | CAS: 10315-07-8 1Wed Sep 24
supply from stock 1-Ethyl-3-hydroxypiperidine %7C CAS: 13444-24-1 1Wed Sep 24
supply from stock 1-%5B(Benzyloxy)carbonyl%5Dpiperidine-4-carboxylic acid %7C CAS: 10314-98-4 1Wed Sep 24
supply from stock 1-Cbz-4-hydroxymethylpiperidine %7C CAS: 122860-33-7 1Wed Sep 24
supply from stock (1-Benzyl-4-piperidyl)methanol %7C CAS: 67686-01-5 1Wed Sep 24
supply from stock Methyl 1-benzylpiperidine-4-carboxylate %7C CAS: 10315-06-7 1Wed Sep 24
supply from stock 1-Benzyl-4-piperidinecarboxylic acid %7C CAS: 10315-07-8 1Wed Sep 24
supply from stock 4-Formylpiperidine-1-carboxylic acid benzyl ester %7C CAS: 138163-08-3 1Wed Sep 24
supply from stock N-Benzyl-3-pyrrolidinol %7C CAS: 775-15-5 2Wed Sep 24
Why is it important to race the solvent line as soon as TLC plate comes out of the chamber 0Tue Sep 23
Too much sample applied in TLC? 0Sat Sep 20
i am working on natural product i want to separate secondary metabolite from which solvent i should start for isolation of single compound such as alkaloides glycosides etc 0Wed Sep 17
explain why ethyl acetate should not be used as a solvent for the recrystallization of alcohols in the presence of acids traces 1Thu Sep 25
TLC 0Tue Sep 16
the sample on TLC plate appears as a band after separation, I want it to be a spot 0Tue Sep 16
Why 6:4 hexane:acetone have both green and yellow color in TLC spotting 0Mon Sep 15
between benzophenone, diphenylmethaanol and biphenyl which one gives the best chance of separating using thin layer chromatography on silica gel 0Mon Sep 15
Explain why ethyl acetate should not be used as a solvent for the recrystallization of alcohols, especially in the present of traces of acid? 0Fri Sep 12
what are the examples of reagents stored in brown bottle, green bottle and white container and the reason why 0Tue Sep 9
why is a dry ice is used as a refrigirant 0Mon Sep 8
what problems will arise if level of developing liquid is higher than the sample spot? 1Sat Sep 20
I need a good procedure for prep TLC. I find that I typically get low yields after using this purification route. 0Fri Sep 5
i am not getting peaks in proton NMR and i am using D2O as solvent and iam increased concentration of compound but no results 2Fri Sep 5
My Active Spot Splits or called bleeding. 0Fri Aug 22
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How to remove hexane impurity from my compounds? In HNMR 1.2 and 0.8 PPM is not going at all 2Fri Sep 5
in fredel craft reaction i am getting hexane impurity,in this reaction iam using dichloro methane as solvet and ferric chloride as a catlyst,i am doing coloumn with etyl acetate and normal hexane, please suggest some of solutions 0Mon Aug 11
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why is water a poor choice of solvent for recrystallisation of iodine 0Sat Aug 2
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why should ethyl acetate not be used as a solvent for recrystalsation of alchohols 0Tue Jul 29
I am spiking a solution but the amount that I add is very small (range of approximately 0.0100g) and my analytical balance cannot show the numbers as the flask is over its max capacity. the spiking solution is also volatile. What can I do to accurately measure the mass of the added spike? 0Tue Jul 29
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is ethyl acetate suitable for recrystallization of alcohols in the presence of acid? 0Mon Jul 28
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If the eluting solvent was changed, would the Rf values for each metal ion change? Explain why. 0Mon Jul 28
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6.%09Once the chromatographic column has been prepared, why is it important to allow the level of the liquid in the column drop to the level of the alumina before applying the solution of the compound to be separated? 1Mon Oct 27
The product and one of the reactant of my reaction are positively charged .How to monitor this reaction? 0Fri Jul 25
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i am getting shouldering peaks which i used to not get before,the problem is with the column,so can u please tell me how to overcome the column troubleshooting? 0Thu Jul 10
How do I measure 1 atm of CO2? Do I use the gas regulator readings to estimate it? 0Wed Jul 9
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why must base-line be placed above the level of water at the start? 0Thu Jun 19
what solvent system is good for tlc and column chromatographic separation of plant dye extracted with acetic acid:water (1:1) 0Tue Jun 17
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supply from stock N-Boc-Piperidine-4-carboxylic acid methyl ester %7C CAS: 124443-68-1 1Tue Jun 10
supply from stock 1-(3-Methoxypropyl)-4-piperidinamine %7C CAS: 179474-79-4 3Fri Jul 18
supply from stock 1-(3-Methoxypropyl)piperidin-4-one %7C CAS: 16771-85-0 11Tue Oct 21
supply from stock Undecanoyl chloride %7C CAS: 17746-05-3 1Tue Jun 10
supply from stock Undecanoic Acid Methylester %7C CAS: 1731-86-8 1Tue Jun 10
supply from stock 1-N-Cbz-3-aminopiperidine %7C CAS: 711002-74-3 1Tue Jun 10
supply from stock 1-(2-Phenylethyl)-4-Piperidinol %7C CAS: 3518-76-1 1Tue Jun 10
supply from stock 1-Isopropyl-4-Piperidinamine %7C CAS: 127285-08-9 3Sat Jul 19
supply from stock 1-(1-Methylethyl)-4-piperidinol %7C CAS: 5570-78-5 1Tue Jun 10
supply from stock 1-Isopropyl-4-piperidone %7C CAS: 5355-68-0 1Tue Jun 10
supply (S)-( )-1-Benzyl-3- 0Tue Jun 10
I collected one of fraction using HP20SS packing using 40%25methanol/water for sponge sample.In reverse phase tlc, the compound still sits at the base.what shall I do? 2Sat Jul 19
nmr yield 0Sat Jun 7
B0di6a Really appreciate you sharing this article.Thanks Again. Fantastic. 203Sun Nov 23
why does product have low RF on tlc than starting material 0Wed May 28
What's the decreasing polarity of p-nitrophenol,developed on silica gel with ether as the solvent? 2Fri Jul 18
explain why hydrogen chloride gas when dissolve in non-polar solvent such as toluene,chloroform do not display any acidic properties while when dissolve in polar solvent e.g water,it shows a strong acidic properties. 2Fri Jul 18
storage condition of reagents in the laboratory 2Fri Jul 18
storage condition in the laboratory 6Tue Oct 21
My compound is not UV visible. I took NMR and it seems it has some impurities. How to separate impurities form my compound?? 0Wed May 7
a peak has been eluting near the void volume of column in blank with an area of 300 and for the sample the same peak is eluted inconsistently with high area in the same sample if injected again and again.what was the reason? 0Mon May 5
0Sun May 4
once the chromatographic column has been prepared why is it important to allow the level of the column to drop to the level of the stationary phase before applying the solution of dyes to be separated 0Wed Apr 30
aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ?????aniline is when taken in HCL along with benzene they give same UV spectra but when taken in CCl4 they give different UV spectra , why ????? 0Mon Apr 28
I have difficulty separating my extract on TLC .although the solvent system is moving the spot but there is no separation .please what should I do? 2Thu May 22
paper chromatograpthy with different solvents 0Wed Apr 23
. A student is given a mixture of three compounds (shown below) and asked to elute through silica column using benzene as a solvent. Predict the order of elution of the above mixture and justify your answer. 2Sat Jul 19
Why should you never let your column to run dry, if it happens what would be the effect on the chromatographic separation? 1Wed May 7
why is it important to allow the level of the liquid in the column to drop to the level of the stationary phase before applying the solution of dyes to be separated? 0Wed Apr 23
zUptLC Hey, thanks for the blog post.Really looking forward to read more. Will read on... 14Tue Oct 21
qJEcoo I truly appreciate this blog post.Much thanks again. Awesome. 10Tue Oct 21
Dmf 1Sat May 3
why must the column remain vertical at all times in column chromatography 2Thu May 29
acid hydrolysis of polysaccharides 0Wed Apr 2
explain the observed differences in Rf values for the separated amino acids 2Sun Apr 13
If you were to carryout a TLC analysis with the crude benzoic acid product, what type of solid phase would you use and what type of solvent would you select as an eluting solvent, to detect the biphenyl impurity? 0Tue Apr 1
I used 1%25 triethylamine in solvent to separating my substance. But, triethylamine exist in my fraction so my fraction doesnt pure. How do i dispose trietylamine in my fraction? Thank you 10Tue Oct 21
1.%09Bromine readily adds to alkenes (bromine test), and reacts readily with aniline to give a tribromo substituted aniline, but no reaction occurs between bromine and benzene unless a Lewis acid such as FeBr3 is present, even though all three compounds contain &%23960; bonds in their molecules. Explain the difference in reactivities. 0Mon Mar 24
What solvent could have been used to separate the color with an Rf value of 0 2Sat Jul 19
o-bromoacetanilide is also formed during the reaction although in much smaller quantity than the p-isomer.at what stage in the procedure is it removed and why is it possible to remove the o-from p-isomer? 2Fri Jul 18
raqa23 Very good article.Thanks Again. Much obliged. 216Sun Nov 23
Once the chromatographic column is prepared, why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compound to be separated? 3Wed Aug 6
During a TLC in 100%25 EtOAc, the spot runs *downward* from the baseline, instead of upward. The EtOAc is not touching the baseline. What is happening? 1Thu May 22
in atlc experiment why must the spot not immersed in the solvent in the developing chamber 1Wed Mar 19
mechanishm for synthesis of dimethone 0Thu Mar 13
In an experiment, Helena is given a mixture of two salts calcium carbonate powder and sodium chloride crystals to separate. to separate them, Helena adds water to the mixture and stirs the mixture for five minutes. She concluded that one salt was soluble and the other one was insoluble. (i) state the observation that Helena made which led to this conclusion. (ii) Identify the soluble salt. 0Thu Mar 13
I have ciprofloxacin at 4 pH and not easy to filter due to impurities, is there any expert to reply and suggest the right solvent for condensation of Q-Acid and piprazin,Thanks 0Thu Mar 13
why is it important to heat 4-bromoacetanilide gently after dissolving it? 2Fri Jul 18
3. If two different substances have the same or nearly the same Rf values, it is difficult to separate (resolve) these materials in a mixture. How could this experiment be changed to separate such a mixture? 11Tue Oct 21
Suppose amino acid ''/%5C' has a higher R1 value than amino acid "B" in a solvent system "1" and the order is reversed in solvent system "2:' Further, suppose that solvent system 'T' has a higher ratio of methanol to ethyl acetate (and is thus more polar) than solvent system "2:' What can you conclude about the structure of amino acid"/%5C' compared to the structure of amino acid "B"? 0Wed Mar 5
3. You have a two-compound mixture, a polar and a nonpolar compound, if you use a 1:1 mixture of hexane:ethyl acetate as your eluent, which compound would you expect to elute from the column first? Explain. 2Tue Jun 24
Would hexane be suitable for a single solvent recrystallization of 4-bromoacetanilide? Why or why not? 7Tue Oct 21
supply from stock 1-Methyl-3-phenylpiperazine | CAS: 5271-27-2 1Tue Jun 10
supply from stock N-Boc-3-pyrrolidinone | CAS:101385-93-7 7Tue Oct 21
supply from stock 1-Benzyl-3-pyrrolidinone | CAS: 775-16-6 3Sat Jul 19
supply from stock 1-Benzyl-3-aminopyrrolidine | CAS: 18471-40-4 3Sat Jul 19
supply 3-Aminopyrrolidine dihydrochloride | CAS:103831-11-4 6Mon Oct 20
supply (3R)-(-)-3-Aminopyrrolidine dihydrochloride | CAS: 116183-81-4 3Fri Jul 18
supply from stock Ethyl oxazole-4-carboxylate | CAS: 23012-14-8 3Fri Jul 18
supply from stock Ethyl 2-amino-1,3-oxazole-4-carboxylate | CAS: 177760-52-0 3Sat Jul 19
supply from stock N-Cbz-3-hydroxypiperidine | CAS: 95798-22-4 1Tue Jun 10
supply from stock 1-Cbz-3-piperidinone | CAS: 61995-20-8 9Tue Oct 21
supply from stock Ethyl 4-amino-1-piperidinecarboxylate | CAS: 58859-46-4 3Fri Jul 18
supply from stock Undecanoic acid | CAS: 112-37-8 1Tue Jun 10
supply from stock Piperidine-4-carboxamide | CAS: 39546-32-2 3Sat Jul 19
supply from stock 1-Boc-4-piperidinecarboxaldehyde | CAS: 137076-22-3 3Sat Jul 19
supply from stock N-Ethyl-4-Hydroxypiperidine,1-Ethyl-4-Piperidinol | CAS: 3518-83-0 1Tue Jun 10
supply from stock 1-Benzyl-3-piperidinol | CAS: 14813-01-5 1Tue Jun 10
supply from stock Piperidin-3-one hydrochloride | CAS: 61644-00-6 3Sat Jul 19
supply from stock 4-Aminopiperidine | CAS: 13035-19-3 3Sat Jul 19
supply from stock 4-Aminopiperidinedihydrochloride | CAS: 35621-01-3 3Sat Jul 19
supply from stock 4-Amino-1-phenethylpiperidine | CAS: 51448-56-7 1Tue Jun 10
supply from stock N-Benzyl-4-BOC-Amino Piperidine | CAS: 73889-19-7 9Tue Oct 21
supply from stock 1-Benzyl-3-aminopiperidine | CAS: 60407-35-4 1Tue Jun 10
supply from stock Ethyl 4-piperidinecarboxylate | CAS: 1126-09-6 1Tue Jun 10
supply from stock N-BOC-piperidine-4-carboxylic acid | CAS: 84358-13-4 7Mon Oct 20
supply from stock Ethyl N-Boc-piperidine-4-carboxylate | CAS: 142851-03-4 3Fri Jul 18
supply from stock Ethyl N-piperazinecarboxylate | CAS: 120-43-4 5Fri Aug 1
supply from stock Ethyl undecanoate | CAS: 627-90-7 1Tue Jun 10
supply from stock Ethyl piperidine-4-carboxylate hydrochloride | CAS: 147636-76-8 1Tue Jun 10
supply from stock Ethyl 2-chloro-1,3-oxazole-4-carboxylate | CAS: 460081-18-9 1Tue Jun 10
supply from stock Ethyl 2-Bromooxazole-4-Carboxylate | CAS: 460081-20-3 3Fri Jul 18
supply from stock Oxazole-4-Carbaldehyde | CAS: 118994-84-6 1Tue Jun 10
supply from stock Ethyl 1-Cbz-piperidine-4-carboxylate | CAS: 160809-38-1 1Tue Jun 10
supply from stock 1-Cbz-4-Piperidone | CAS:19099-93-5 3Sat Jul 19
supply from stock 1-phenethyl-4-piperidone | CAS:39742-60-4 3Sat Jul 19
supply from stock tert-Butyl 1-piperazinecarboxylate | CAS:57260-71-6 3Fri Jul 18
supply from stock tert-Butyl 1-piperazinecarboxylate %7C CAS:57260-71-6 4Sat Jul 19
supply from stock tert-Butyl 3-aminopyrrolidine-1-carboxylate %7C CAS:186550-13-0 12Mon Oct 20
supply (3R)-(-)-3-Aminopyrrolidine dihydrochloride %7C CAS: 116183-81-4 12Tue Oct 21
supply from stock Ethyl oxazole-4-carboxylate %7C CAS: 23012-14-8 4Fri Jul 18
supply from stock N-Cbz-3-hydroxypiperidine %7C CAS: 95798-22-4 10Tue Oct 21
supply from stock 1-Cbz-3-piperidinone %7C CAS: 61995-20-8 4Sat Jul 19
supply from stock Ethyl 4-amino-1-piperidinecarboxylate %7C CAS: 58859-46-4 6Tue Aug 5
supply from stock Undecanoic acid %7C CAS: 112-37-8 8Mon Oct 20
supply from stock Piperidine-4-carboxamide %7C CAS: 39546-32-2 4Sat Jul 19
supply from stock 1-Boc-4-piperidinecarboxaldehyde %7C CAS: 137076-22-3 2Sun Feb 23
supply from stock Ethyl 1-benzylpiperidine-4-carboxylate | CAS: 24228-40-8 4Fri Jul 18
supply from stock Ethyl 1-benzylpiperidine-4-carboxylate %7C CAS: 24228-40-8 12Tue Oct 21
supply from stock N-Ethyl-4-Hydroxypiperidine,1-Ethyl-4-Piperidinol %7C CAS: 3518-83-0 2Sun Feb 23
supply from stock 1-Benzyl-3-piperidinol %7C CAS: 14813-01-5 10Tue Oct 21
supply from stock Piperidin-3-one hydrochloride %7C CAS: 61644-00-6 2Sun Feb 23
supply from stock 4-Aminopiperidine %7C CAS: 13035-19-3 2Sun Feb 23
supply from stock 4-Aminopiperidinedihydrochloride %7C CAS: 35621-01-3 8Tue Aug 19
supply from stock 4-Amino-1-phenethylpiperidine %7C CAS: 51448-56-7 4Fri Jul 18
supply from stock N-Benzyl-4-BOC-Amino Piperidine %7C CAS: 73889-19-7 10Tue Oct 21
supply from stock 1-Benzyl-3-aminopiperidine %7C CAS: 60407-35-4 14Tue Oct 21
supply from stock Ethyl 4-piperidinecarboxylate %7C CAS: 1126-09-6 3Sun Feb 23
supply from stock N-BOC-piperidine-4-carboxylic acid %7C CAS: 84358-13-4 4Wed Aug 6
supply from stock Ethyl N-Boc-piperidine-4-carboxylate %7C CAS: 142851-03-4 4Tue Aug 5
supply from stock Ethyl N-piperazinecarboxylate %7C CAS: 120-43-4 8Tue Aug 19
supply from stock Pyrrolidin-3-one hydrochloride %7C CAS: 3760-52-9 4Sat Jul 19
supply from stock Ethyl undecanoate %7C CAS: 627-90-7 10Tue Oct 21
supply from stock Ethyl piperidine-4-carboxylate hydrochloride %7C CAS: 147636-76-8 2Sun Feb 23
supply from stock Ethyl 2-chloro-1,3-oxazole-4-carboxylate %7C CAS: 460081-18-9 6Tue Aug 5
supply from stock Ethyl 2-Bromooxazole-4-Carboxylate %7C CAS: 460081-20-3 8Tue Aug 5
supply from stock Oxazole-4-Carbaldehyde %7C CAS: 118994-84-6 6Wed Aug 6
supply from stock Ethyl 1-Cbz-piperidine-4-carboxylate %7C CAS: 160809-38-1 6Tue Oct 21
why we use dichloro methane as mobile phase for acetanilide tlc 0Sun Feb 23
WHAT HAPPENS IF THE PERCENTANGE OF DCM IS DOUBLED IN TLC 2Fri Jul 18
What would happen if a TLC plate was using pure methanol as a solvent system 3Sat Jul 19
Q)When conducting a column under air pressure the silica cracks and spilts when pressure is released (typically 0.015 mm silica). A)This is due to high concentrations of air being forced into your solvent. Elute with vacuum instead if possible. 0Wed Feb 19
how can the reagent be arrange and stored. 0Tue Feb 18
Regarding the sample we use for seperation in this experiment, what result do you expect if the column is eluted with i) pure hexane and ii) pure ethyl acetate? Explain 5Tue Oct 21
4-bromoacetanilide 0Sun Feb 16
Would hexane be suitable for a single solvent recrystallization of 4-bromoacetanilide? Why or why not? 3Mon Feb 24
what happens if an ink sample consisting of five dyes is spotted on a piece of chromatography paper and placed in a chamber with mobile phase. 2Fri Jul 18
why is it important to trace the solvent line as soon as the TLC plate comes out of the table? 1Thu Feb 20
I am preparing ciprofloxacin HCl,bur at crude stage it becomes so sticky and can not be filtered,please reply why it happens and how to overcome the problem? 2Wed Aug 6
my problem is on smearing on plastic despite adjusting on blade holder and combination of ink and solvent 0Thu Feb 6
why must the starting line containing the plant extract be placed above the solvent level at the beginning of the experiment? 3Fri Jul 18
Why is it important to heat the mixture of benzophenone, acetic acid and isopropanol? 2Sat May 10
FKSh5S Say, you got a nice blog post.Thanks Again. 22Tue Oct 21
I am preparing ciprofloxacin HCl,bur at crude stage it becomes so sticky and can not be filtered,please reply why it happens and how to overcome the problem? Thanks for help 8Tue Oct 21
why must the starting line containing the plant extract be placed above the solvent level at the beginning of the experiment? 1Sat Feb 8
Why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compound to be separated? 11Sun Nov 23
conversion formic acid to acitic acid. 1Fri Jan 24
If any compound give bright whit color in TLC plate which fluorescence under UV light, what compound it will indicate ? 0Wed Jan 15
Describe different ways to split up a mixture of benzene and methanol into its components using two phase system separation. 0Sun Jan 12
what is the major product isolated after acidification of the soap 2Fri Jul 18
Why NaOH is used commonly used strongly bases? 0Wed Dec 25
Melting point 0Tue Dec 24
4.%09In carrying out an analysis of a mixture, what do you expect to see when the TLC plate has been allowed to remain in the developing chamber too long, so that the solvent front has reached the top of the plate? 1Thu Feb 20
I have a compound containing triptycene moiety, the solubility of the compound is very low in common solvents. I have taken the HNMR in CDCl3, all protons except aromatic proton of triptycene are coming. But the aromatic proton of triptycene are not coming. What can I do? 1Sun Mar 2
I have a compound containing triptycene moiety, the solubility of the compound is very low in common solvents. I have taken the HNMR in CDCl3, all protons except aromatic proton of triptycene are not coming. What can I do? 1Wed Jan 1
why is it important to add the sodium borohydride to your solution at 0 degree celius and in small portions? 8Fri Aug 1
how to silica decompose our compound 6Tue Oct 21
Why ethyl acetate should not be used as a solvent for recrystallization of alcohols in the presence of traces of acid 6Tue Aug 5
rf of value of para nitrobenzonic acid 0Mon Nov 25
Name of the metal by which formic acid and acitic acid distinguish 0Sat Nov 23
once the chromatographic 0Thu Nov 21
write a rational mechanism for the conversion of cyclohexanol into cyclohexene using a strong acid 0Wed Nov 20
Why is so difficult to separate crude diol from reaction mixture ? 0Tue Nov 19
When reducing benzil, why is it important to add the sodium borohydride to your solution at zero degrees Celsius and in small portions? 7Tue Oct 21
How to separate two compounds with large difference in Rf values? They come simultaneously from the column irrespective of the different mobile phase tried. 3Fri Jul 18
why the baseline placed above the level of the solvent? 13Tue Oct 21
If two different substances have the same or nearly the same Rf values, it is difficult to separate (resolve) these materials in a mixture. How could this experiment be changed to separate such a mixture? 9Tue Oct 21
DEAR SIR IN MY TLC METER THE DISPLAY ONLY SHOEING TLC 2.01 NOT NOT GOING AHEAD THIS IS STUCK DISPLAY AND THERE IS NO ANY MOVEMENT IN DISPLAY PLEASE SUGGESTT ME WHAT TO DO AND FROM WHERE I SHOULD CHECK 3Fri Jul 18
mechanism of Grignard reagent of 4-bromoacetanilide that attack to the acetone and followed by H 1Sun Oct 27
1.What is the principal mechanism in colunm chromatography. 2.how are silica and alumina activated in column chromatography? 3.how are compounds are detected in column chromatography? 0Thu Oct 24
Suppose you prepared benzil by the oxidation of benzoin, describe how you could use TLC (thin layer chromatography) to decide when the reaction is complete. 1Tue Apr 1
Say, you got a nice blog. Much obliged. 217Sun Nov 23
Major thankies for the blog post.Really thank you! Really Cool. 34Sun Nov 23
Major thankies for the blog post.Thanks Again. 30Sun Nov 23
This is one awesome article.Thanks Again. Really Great. 28Tue Oct 21
what would have happened if 50:50 ethyl acetate petrolium ether was used to the cholesterol before dichloromethane? 4Thu Oct 30
difference between cppt and pppt 2Fri Jul 18
Suppose two cations have the same Rf values and are the same colored spots how might you resolve their presence in a mixture using paper chromatography? 10Tue Oct 21
i am synthesising propargylated chalcones from propargylated accetophenone and benzaldehyde using aqueous KOH as base. After the formation of solid mass i reduced the mass and kept it overnight after that i extracted it with ethyl accetate and water. but a gelly layer was formed in between ethylaccetate and water containing product.please answer my quetion 6Tue Oct 21
what is CAS of aceclofenac sodium how is syntheised dr kurani 0Sat Oct 5
TLC chromotagraphy If the eluent had not efficiently separated the two spots on the plate, should I add more ethyl acetate or more acetic acid? Why? 2Mon Sep 22
What would be the result of the following errors in TLC technique: a) Too much sample applied? 1Thu Oct 3
Why should a reagent bottle be covered 0Wed Sep 18
i have different extract of pomegranate peel with different solvent like ethyl acetate,hexane,chloroform,methanol,benzene and doing tlc with different solvent ratio but spot doesnot move from the base line so please give some solvent name for above tlc experiment? 0Tue Sep 17
supply 1-benzyl-3-piperidone hydrochloride %7C cas%3a 50606-58-1 2Fri Jul 18
supply 1-Benzyl-3-piperidone hydrochloride %7C CAS: 50606-58-1 6Tue Aug 5
supply from stock 1-Benzyl-4-hydroxypiperidine %7C CAS: 4727-72-4 3Sat Jul 19
supply from stock Benzyl 4-hydroxy-1-piperidinecarboxylate %7C CAS: 95798-23-5 4Fri Jul 18
supply from stock Isopropyl 4-hydroxypiperidine-1-carboxylate %7C CAS: 832715-51-2 5Tue Aug 19
supply from stock 4-Hydroxy-4-methylpiperidine.HCl %7C CAS: 3970-68-1/586375-35-1 6Tue Aug 5
supply from stock 4-Hydroxy-4-methylpiperidine-1-carboxylic acid tert-butyl estercarboxylate %7C CAS: 406235-30-1 4Wed Aug 6
supply from stock 1-Boc-3-hydroxypiperidine %7C CAS:85275-45-2 3Sat Jul 19
supply from stock 1-Aminopiperidine %7C CAS: 2213-43-6 2Sun Sep 15
supply from stock N-Aminopiperidine hydrochloride %7C CAS: 63234-70-8 4Tue Aug 5
supply from stock 4-Amino-1-benzylpiperidine %7C CAS:50541-93-0 8Tue Oct 21
supply from stock 1-Cbz-4-aminopiperidine %7C CAS: 120278-07-1 4Fri Jul 18
supply from stock N-BOC-3-aminopiperidine %7C CAS:184637-48-7 6Tue Aug 5
supply from stock 3-N-Boc-aminopiperidine %7C CAS:172603-05-3 5Mon Aug 18
supply 1-Boc-4-(aminomethyl)piperidine %7C CAS:144222-22-0 4Fri Jul 18
supply from stock 1-Boc-4-methanesulfonyloxypiperidine %7C CAS: 141699-59-4 3Fri Jul 18
supply from stock 1-Methyl-3-phenylpiperazine %7C CAS: 5271-27-2 4Fri Jul 18
supply from stock 1-Benzyl-3-pyrrolidinone %7C CAS: 775-16-6 2Sun Sep 15
supply from stock 1-Benzyl-3-aminopyrrolidine %7C CAS: 18471-40-4 2Sun Sep 15
supply 3-Aminopyrrolidine dihydrochloride %7C CAS:103831-11-4 2Sun Sep 15
supply from stock Ethyl oxazole-4-carboxylate %7C CAS: 23012-14-8 by Shanghai Hobor chemical co.,Ltd 12Tue Oct 21
supply from stock Ethyl 2-amino-1,3-oxazole-4-carboxylate %7C CAS: 177760-52-0 2Sun Sep 15
I want to use a reagent (HEPES) that is very much hydrated, How can I weight it accurately? can I put it in an oven to dehydrate? 0Fri Sep 13
What can u react with potassium to give a product 0Thu Sep 12
shanghai hobor chemical co.%2cltd is professional r&d and manufacturing of intermediates%2cactive ingredients%2c our custom synthesis department can supply chemical development%2c custom synthesis services quantities ranging from grams to tons.more details please visit our company website 0Tue Sep 10
I get a single spot with tailing on tlc after isolating compound using column chromatography. How can i purify to get the single spot? 3Sat Jul 19
supply from stock 4%2c4-piperidinediol hydrochloride %7c cas%3a40064-34-4 0Sun Sep 8
supply from stock 1-N-(Methylsulfonyl)-4-piperidinone %7C CAS: 218780-53-1 0Sun Sep 8
supply from stock 1-Cbz-4-Piperidone %7C CAS:19099-93-5 10Tue Oct 21
supply from stock 1-phenethyl-4-piperidone %7C CAS:39742-60-4 12Tue Oct 21
supply from stock 4,4-Piperidinediol hydrochloride %7C CAS:40064-34-4 2Sun Sep 8
Determination of shelflife of prepared crystal violet 0Tue Aug 27
How to Determine the shelf life of prepared reagents 0Tue Aug 27
Deterination of shelf life of prepared crystal violet 2Fri Jul 18
To purify my products, I need to use a basic silica column chromatography, with tryethylamine. But it coordinates to my product somehow and is not removed under vacuum. Are there other bases I can use with lower boiling points and/or less coordination properties? 0Tue Aug 20
why diphenyl is called organic compounds 0Sat Aug 17
N-carbethoxy-4-hydroxy piperidine hplc analysis methods 3Sat Jul 19
in analysis of xanthine piperidine derivative we are not getting the propercontent of 3-boc-amino piperidine by gc 0Thu Aug 1
How can I remove triethylene glycol impurity from my reaction mixture? Its not UV active so I cannot see by TLC. 4Tue Oct 21
why silica is slightly acidic in nature? 0Thu Jul 25
I am doing NMR in D2O w. the presaturation mode. The water peak is very broad that it covered my peaks of interest. I tried to increase the temperature, but our cyroprobe only allow me to increase the temperature as high as 330K at the 600 & 800MHz. At T%3D303K, the peaks of interest showed up on the tail of water peak. But when I ran a 2D HSQCPSpr (phase sensitive HSQC with presaturation), the peaks of interest were not shown up in the 2D spectrum. I tried to get the spectrum from the 500MHz one with 80 C, but the resolution was poor and the water peak is still covering my region of interest (4.4 ppm to 5 ppm). Can anyone suggest me another way to get a spectrum with the region of interest showing up? Thank you very much for your help! 0Fri Jul 12
How to remove water peak from my sample? (Adding sodium sulfate does not help in my case) 3Sat Jul 19
how can premature recrystallization be avoided? 1Wed Jul 17
I want to benefit from the upincmog class: Deep Listening Training for Empaths in Service.How do I register for this class?I don't see a prompt to reserve a seat or make the %2410 payment.Best,SusanLorraine 0Mon Jul 1
how can i increase the distance between two spots on TLC plate for easily separation by column chromatography? 5Thu Aug 14
my fractions are cloudy,turbid after eluting with silica,i guess silica is responsible,but how do i get silica out of them.? 3Wed Jul 17
The compounds I am trying to separate are basically the same! The only difference is the R group on the boronic acid is replaced with an OH group to form boric acid. Boric acid is super polar and I cannot get it to lift off of the baseline in TLC. Is there any way I can qualify the amount of boric contaminant or at least serperate the two? 5Tue Oct 21
my product is acid sensitive.when i tried to seperate my product from reaction mixture containing reactant by column chromatography using silica gel which is slghtly acidic the reaction get reversed how can i seperate it from reactant 3Sat Jul 19
Why is water a pooor solvent for recrystallisation of iodine? 1Sun Jun 2
why moisture shift from down field to up field in VT NMR experiment 0Tue May 7
i am using a solvent mixture of 1 butanol:glacial acetic acid:water, but the rf values are almost similar, what will b the solution 2Sat Jul 19
What will be the result if my products are dissolved in the solution about the column? (column chromatography) 0Fri Apr 12
What will be the result if my products are dissolved in the solution about the column? 1Tue Jun 4
What if my sample does not dissolve in any of the solvents? 5Thu Aug 14
on TLC, my best mobile solvent is butanol:acetic acid :water, can i use this same B;A:W solvent as my eluting solvent in column chromatography, without encountering problems as butanol is less polar? 0Thu Mar 21
compound only soluble in HCl and NaOH hoe can take NMR? 2Sat Aug 3
compound not soluble in solvents how can take NMR? 0Fri Mar 15
the easier way to know acompound in spectroscopy problems? 0Fri Mar 1
What is the best apparatus to use for the conversion of a carboxylic acid to the corresponding acid chloride with SOCl2 on a ca. 1g scale? 0Mon Feb 25
What will be the result if too much sample is applied in TLC 2Thu Mar 14
I am doing a qualitative test for ciprofloxacin in pharmaceutical products. According to the British pharmacopea, the difference between the spots of the standard anf test splutions should have a percentage of 0.2%25. the values i get are o.1mm different but not percentage wise. How can i get the 0.2%25 difference 8Tue Oct 21
I am doing a qualitative test for ciprofloxacin in pharmaceutical products. According to the British pharmacopea, the difference between the spots should have a percentage of 0.2%25. the values i get are o.1mm different but not percentage wise. How can i get the 0.2%25 difference 6Tue Oct 21
My question is regarding TLC. The reactant and product are polyamine type. The two spots are not moving even I tried with various eluents combination. And, the spots are moving in the shape of flame. Kindly do suggest. 2Tue Feb 12
what is the most possible ratios of mobile phases? or all ratios must be tried? 0Sun Feb 3
How to remove the pyridine solvent from the reaction mass with out making Azeotrop? 1Tue Mar 19
What color does benzil reagent gives for visualization of fatty acid on thin layer plate. 0Sat Jan 26
supply from stock (S)-3-(Boc-amino)pyrrolidine CAS: 122536-76-9 3Sat Jul 19
Shanghai Hobor chemical co.,Ltd is professional R&D and manufacturing of intermediates,active ingredients, Our custom synthesis department can supply chemical development, custom synthesis services quantities ranging from grams to tons.more details please visit our company website 8Tue Oct 21
supply from stock (R)-3-(Boc-amino)pyrrolidine %7C CAS: 122536-77-0 1Thu Jan 17
What is the function of the components of the solvent system of Butanol: Acetic Acid: Distilled Water in separating amino acids? 0Wed Jan 16
supply (S)-( )-1-Benzyl-3-aminopyrrolidine CAS:114715-38-7 3Fri Jul 18
supply (R)-(-)-1-Benzyl-3-aminopyrrolidine CAS:114715-39-8 1Tue Jan 15
supply (3S)-( )-3-Aminopyrrolidine dihydrochloride CAS:116183-83-6 3Sat Jul 19
supply (R)-1-Boc-2-cyanopyrrolidine CAS:228244-20-0 1Tue Jan 15
supply (S)-1-Boc-2-cyanopyrrolidine CAS:228244-04-0 1Tue Jan 15
supply (R)-2-(Aminomethyl)-1-N-Boc-pyyrolidine CAS:259537-92-3 3Fri Jul 18
supply (S)-1-N-Boc-2-(aminomethyl)pyrrolidine CAS:119020-01-8 7Mon Aug 4
supply 3-Aminopyrrolidine dihydrochloride CAS:103831-11-4 1Tue Jan 15
supply (R)-1-Boc-3-hydroxypyrrolidine CAS:103057-44-9 1Tue Jan 15
supply (R)-4-Boc-2-methylpiperazine CAS:163765-44-4 1Tue Jan 15
supply (S)-4-N-Boc-2-methylpiperazine CAS:147081-29-6 1Tue Jan 15
supply (S)-1-N-Boc-2-methylpiperazine CAS:169447-70-5 1Tue Jan 15
supply N-Boc-piperazine-2-carboxylic acid methyl ester CAS:129799-15-1 8Mon Oct 20
supply 1-Boc-2-Methylpiperazine CAS:120737-78-2 1Tue Jan 15
supply N-Boc-3-Ethylpiperazine CAS:438049-35-5 3Fri Jul 18
supply 4-N-Boc-2-Methyl-piperazine CAS:120737-59-9 1Tue Jan 15
supply from stock 1-(3-Trifluoromethylphenyl)piperazine hydrochloride CAS: 16015-69-3 1Tue Jan 15
supply from stock Piperazin-2-one CAS:5625-67-2 1Tue Jan 15
supply (R)-3-Aminopiperidine dihydrochloride CAS:334618-23-4 7Tue Aug 5
supply (S)-3-Aminopiperidine dihydrochloride CAS:334618-07-4 1Tue Jan 15
supply (R)-(-)-1-Benzyl-3-hydroxypiperidine CAS:91599-81-4 3Fri Jul 18
supply (S)-( )-1-Benzyl-3-hydroxypiperidine CAS:91599-79-0 1Tue Jan 15
supply 1-Boc-4-Methylaminopiperidine CAS: 147539-41-1 2Tue Jan 15
supply 3-N-Boc-Aminomethylpiperidine CAS: 142643-29-6 3Sat Jul 19
supply 4-(Boc-Aminomethyl)piperidine CAS: 135632-53-0 7Tue Oct 21
supply 4-(2-Aminoethyl)-1-Boc-piperidine CAS: 146093-46-1 1Tue Jan 15
supply 1-Boc-4-(aminomethyl)piperidine CAS:144222-22-0 1Tue Jan 15
supply 3-Aminomethyl-1-N-Boc-piperidine CAS: 162167-97-7 3Fri Jul 18
supply 2-(Aminomethyl)-1-Boc-piperidine CAS: 370069-31-1 1Tue Jan 15
supply 4-(Aminomethyl)piperidine CAS: 7144-05-0 1Tue Jan 15
supply 2-(Aminomethyl)piperidine CAS: 22990-77-8 1Tue Jan 15
supply (S)-1-Boc-3-hydroxypiperidine CAS:143900-44-1 3Sat Jul 19
supply (R)-1-Boc-3-Hydroxypiperidine CAS:143900-43-0 5Tue Oct 21
supply (S)-3-Hydroxypiperidine hydrochloride CAS:475058-41-4 3Sat Jul 19
supply (R)-3-Hydroxypiperidine hydrocloride CAS:198976-43-1 3Mon Jul 1
supply (S)-3-N-Boc-aminopiperidine CAS:216854-23-8 3Sat Jul 19
supply (R)-3-(Boc-Amino)piperidine CAS:309956-78-3 1Tue Jan 15
supply (S)-3-Amino-1-N-Boc-piperidine CAS:625471-18-3 1Tue Jan 15
supply (R)-1-Boc-3-Aminopiperidine CAS:188111-79-7 1Tue Jan 15
supply from stock 3-N-Boc-aminopiperidine CAS:172603-05-3 3Sat Jul 19
supply from stock tert-Butyl 1-piperazinecarboxylate CAS:57260-71-6 4Tue Jan 29
supply from stock 1-Benzylpiperazine dihydrochloride BZP CAS: 5321-63-1 1Tue Jan 15
supply from stock 1-benzylpiperazine BZP CAS:2759-28-6 3Sat Jul 19
supply from stock N-BOC-3-aminopiperidine CAS:184637-48-7 3Fri Jul 18
supply from stock 4-N-BOC-aminopiperidine CAS:73874-95-0 1Tue Jan 15
supply from stock 4-Amino-1-Boc-piperidine CAS:87120-72-7 3Fri Jul 18
supply 4-Amino-1-benzylpiperidine CAS:50541-93-0 3Sat Jul 19
supply from stock 1-Methylpiperidin-4-amine CAS:41838-46-4 1Tue Jan 15
supply from stock 4-Chloro-N-methylpiperidine CAS:5570-77-4 3Sat Jul 19
supply 1-Boc-3-hydroxypiperidine CAS:85275-45-2 1Tue Jan 15
supply from stock 3-hydroxypiperidine CAS:6859-99-0 1Tue Jan 15
supply from stock N-Boc-4-hydroxypiperdine CAS:109384-19-2 9Tue Oct 21
supply from stock Ethyl 4-hydroxypiperidine-1-carboxylate CAS: 65214-82-6 3Sat Jul 19
supply from stock N-Methyl-4-piperidinol CAS:106-52-5 1Tue Jan 15
supply from stock 4-hydroxypiperidine CAS:5382-16-1 3Sat Jul 19
supply from stock 1-Boc-3-piperidone CAS:98977-36-7 3Fri Jul 18
supply from stock 1-Cbz-4-Piperidone CAS:19099-93-5 1Tue Jan 15
supply from stock N-(tert-Butoxycarbonyl)-4-piperidone CAS:79099-07-3 1Tue Jan 15
supply from stock N-carbethoxy-4-piperidone CAS:29976-53-2 3Fri Jul 18
supply from stock 1-phenethyl-4-piperidone CAS:39742-60-4 1Tue Jan 15
supply from stock N-Benzyl-4-piperidinone CAS:3612-20-2 1Tue Jan 15
supply from stock 1-methyl-4-piperidone CAS:1445-73-4 1Tue Jan 15
supply from stock 4,4-Piperidinediol hydrochloride CAS:40064-34-4 3Sat Jul 19
supply (S)-3-Pyrrolidinol hydrochloride CAS:122536-94-1 1Tue Jan 15
supply from stock (R)-(-)-3-Pyrrolidinol hydrochloride CAS:104706-47-0 3Fri Jul 18
supply from stock (R)-(-)-N-Boc-3-pyrrolidinol CAS:109431-87-0 1Tue Jan 15
supply from stock (S)-( )-1-Boc-3-hydroxypyrrolidine CAS:101469-92-5 7Tue Oct 21
supply (S)-(-)-1-Boc-3-aminopyrrolidine CAS:147081-44-5 1Tue Jan 15
supply (3R)-(-)-3-Aminopyrrolidine dihydrochloride CAS:116183-81-4 1Tue Jan 15
supply (R)-( )-1-Boc-3-aminopyrrolidine CAS:147081-49-0 Hobor chemical co.,Ltd 2Tue Jan 15
supply from stock tert-Butyl 3-aminopyrrolidine-1-carboxylate CAS:186550-13-0 Shanghai Hobor chemical co.,Ltd is professional R&D and manufacturing of intermediates,active ingredients, Our custom synthesis department can supply chemical development, custom synthesis services quantities ranging from grams to tons.more details please visit our company website 4Sun Jan 27
supply from stock N-Boc-3-pyrrolidinone %7C CAS:101385-93-7 4Mon Jul 1
c 0Tue Jan 15
on the TLC plate i loaded 2 things starting material (reactant) and the product how could i know whether the reaction is complete or not 1Sat Jan 19
How does the recrystallization procedure remove solvent soluble impurities? 0Thu Jan 3
why could my nmr look different for my product and starting material after epoxidation? 0Tue Dec 11
my compound contains terminal alkyne, but when i tried it to purify by coloumn chromatography containing 100-200 mesh silica gel, i didnt found it???? 1Sat Jan 19
can i use DMF as solvent in LDA reaction???? 0Thu Dec 6
im getting lot of impurities in the range 1 to 3 ppm even though i use distilled pet ether petether. How can i avoid them 0Wed Dec 5
Why only NH or OH proton can be D2O exchange but not CH proton? 2Mon Dec 10
4-bromoacetanilide polar 4Sun Dec 9
1.%09Suppose you prepared benzil by the oxidation of benzoin, describe how you could use TLC (thin layer chromatography) to decide when the reaction is complete. 2Tue Oct 22
how to made deuterated diphenylmethanol 2Mon Dec 10
can we separate amino acid and amino ester hydrochloride 0Mon Nov 12
solvent which are used for non aqeous titration 0Wed Nov 7
What problem with ensue if the level of the developing liquid is higher than the applied spot in a TLC analysis? 20Thu Nov 6
my compound contains double bond NH,when i m doing the column then it simply converted in to carboxylic group,the reason is that silica is in acidic form it converted double bond NH to Double bond O , so now i m in problem that how to separate that compound? 1Tue Nov 6
How do I know when I need to use a gradient solvent system for chromatography? 11Tue Oct 21
reductive opening of benzylidene 6Tue Aug 5
%FD must take three different spot on tlc plate one of tehem is polar and the others are non polar and close to each other normally %FD can take such this spot with a mobile phase like etoac :hex 1:2 but for this molecule %FD use etoac:hex 1:4 bu %FD couldnt separate what can %FD do ? 5Tue Aug 5
My compound decomposes on silica, and I am not getting separation on neutral alumina what should i do? 6Sat Nov 3
What is my compound keep change from liquid state to semi solid, then added with silica powder for solid loading, it remains at semi solid state? What should i do? 2Sat Nov 3
In general, we assume that in a mixture, each component will show the same Rf value it shows when it runs alone. However, sometimes in the presence of a large amount of a second component the Rf is affected. Why does this behavior occur? TLC experimentation 19Sun Nov 23
what should yoou do before using reagents 0Sun Sep 16
what is mean by radial development in paper chromatography 0Thu Sep 13
In my compound I have Methyl, Phenyl chloro acetamide type structure where I couldn't see proper splitting for aromatic, as well as for ch2cl group. 0Wed Sep 12
no spot are seen on the plate 0Tue Sep 11
many random spotseen on the plate 0Tue Sep 11
the compound runs as a streak rather than a spot 1Tue Nov 6
I need to take TLC of "reactive dyes" so kindly tell which solvent should I use and what should be the percentage of dyes solution should I use for following. 0Sun Sep 2
Why are most of the questions on this website worded poorly and written by complete morons? 4Tue Jan 8
How we can distinguish between 1 HNMR peaks of NH and NH2 in cyclic amine? 0Fri Jul 27
I know how to remove grease from my apparauses. But how to remove grease by column chromatograpy? Is there anyone who knows about solvent conditions? Beacause the substrate which will be isolated is in not-validated apparatus. 2Fri Jul 27
why are unused reagents not returned to the original bottle? 5Fri Jul 18
my meth powder has turned to oil after mixing it what do i do next to crystalize it help meeeee;-%5B 1Sat Jul 28
What is the best way to remove m-CPBA following epoxidation? 4Wed Nov 14
Explain the difference between co-precipitation and post precipitation 10Sat Oct 25
What is the number of atoms in one molecule of sulfur trioxide? 2Thu Oct 30
How to work up reduction reaction with dibalh and give me all the required steps to take up the reaction 1Wed Oct 8
If all spots were at the very top of TLC plate and I want to decrease polarity of the solvent to be able to produce good separation, do I increase or decrease the percent of hexane 4Tue Sep 25
How do you obtain %25 composition of a reaction on GC using an internal standard? 2Fri Jul 27
my compound is too polar in nature to run on tlc.it get stcks to the base line. 2Thu Jun 7
my compound is sticky in nature.i have tried hexane or petroleum ether but of no use.suggestions regarding this. 10Tue Aug 5
WHAT IS A STROHMEYER APPARATUS??? 0Wed May 16
What is a strohmeyer apparatus? 0Wed May 16
How to solidify a semisolid compound because a semisolid compound can't be sent for CHN analysis? Also I'm pretty sure that it's a solid. 1Tue May 22
in carrying out an analysis of a mixture, what do you expect to see when the TLC plate has been allowed to remain in the developing chamber too long, so that the solvent front has reached the top of the plate? 1Wed May 23
hi, what's the best procedure to work up Red-Al reaction? 0Sat Apr 28
what is Handellah 0Wed Apr 25
i am facing the problem regarding the flow rate while running the column in ethyl acetate and methanol... what could be the reason? 0Wed Apr 25
my chemical compound goes with solvent front,Is it correct? 0Tue Apr 24
How to prepare Ni3Al Nickel aluminide intermetalic powder? 2Tue May 15
What is difference between recrystallization and fractional recrystallization 2Mon May 14
My compound will not dissolve in the eluent and therefore i have to place it in the topic of the silica gel in 3 separate tries is this a problem? 2Mon May 14
chanding the drug conc leads to increase the Rf in the same system. why? 2Mon May 14
For column chromatography, can you load a solid sample immediately onto the silica gel without adsorbing it to silica first? 2Tue May 15
I have a syringe with the sample in it, and I want to weigh it. How? 1Tue May 15
Will NH protons get exchanged with acetone-d6 (in the absence of D2O) 0Fri Mar 23
I Dueterated my compound with MeOH-d4 to check the OH proton. Now how can I get my Startimg material back??????????/ 0Thu Mar 22
Over loading of sample 0Wed Mar 21
report the yield of the initial and final product and same to be recrystalisted by using suitable solvent and placing for the examintion 2Tue Mar 27
What is the purpose of making derivatives of unknowns 0Mon Mar 19
A hot solution of a particular compound was allowed to cool to room temperature. After waiting a few minutes, it was noticed that the crystallization had not taken place. Discuss two ways to induce crystallization. 5Sat May 12
6.%09You have recrystallized ferrocene by the two-solvent method (acetone-water). Based on the following solubility test results for ferrocene, suggest (i) another pair of solvents that may be used in the two-solvent method and (ii) a solvent that may be used for the single solvent method 3Mon Apr 2
why is it possible to have a clean seperation of benzoin from dichlomethane 0Sat Mar 17
prepare good quality and quantity of p-Bromoacetanilide from Anilide? 2Tue Mar 27
A hot solution of a particular compound waz allowed to cool to room temperature.After waiting a few minutes,it waz noticed that the crystallization had not taken place.Indicate and discuss two ways to induce crystallization. 1Tue Mar 20
ion exchange 0Mon Mar 12
%250A 0Fri Mar 9
What happens to the Rf if you used water as a solvent, and in the second you used ethyl alcohol as the solvent. 0Thu Mar 8
The solvent peak and the water peak are missing when they are usually there 0Wed Mar 7
what color is bromoacetanilide suppose to be 1Sun Apr 1
I did a boc deprotection of my compound and tlc showed a completion and IR as well confirm a presence of a free amine but im still seeying a huge t-butyl pic in my H NMR proton what can i do to get rid of that 2Tue Mar 27
whatis the best solvent for crystalizing cholesterol? 2Tue Mar 27
If you had a mixture of aniline and naphthalene describe briefly how you would separate the mixture. 0Mon Mar 5
what would happen if a sample was immersed in the chromatography solvent, instead of suspended above it? 2Tue Mar 27
I am going to extract glycoside from gravity column chromatography with silica gel,what solvent should I use and in which ratio I should use? 0Wed Feb 29
my product is only soluble in DMSO/DMf ,how can I recrystallize from it. 0Tue Feb 28
I have collected crude extractive compountd of plant material from acetone and benzene-etanol solvents. please give sugession how to purify and chrecterise it ? 0Mon Feb 27
My compound is relatively non-polar, but once it crystallizes out of solution, it's nearly impossible to get it back into solution. I think this also occurs on silica, often losing 50%25 per step, flushing the column doesn't help. Any tips? 0Mon Feb 27
I am dealing with a compound having long alkyl chain backbone(12 carbon)with carboxylic acid end group. When I tried to run the TLC it showed tailing in near to every solvent. (I used different proportion of Diethyl ether, ethyl acetate, hexane, chloroform, methanol, Dichloromethane, few drops of acetic acid and ammonium hydroxide)but I would not get the better seperation. Is it possible that carboxylic acid will make complex with silica. Is methylation of acid will help in better seperation. How can I solve this problem 3Sat Apr 7
my sample (cyclodextrin sulfonate compound) is soluble in water and pH 8-9, Reverse phase TLC development. I have problem with purification with LiChrospher%AE RP-18 endcapped silica gel. Please tell me how to do. thank in advance, 0Sat Feb 25
I have extracted plant extracts using water, which means mainly the polar solvents has been extracted.Now I would like to know which solvent or solvent mixture to be used to obtain the spots?? Also what should I use as a developing agent? 0Fri Feb 24
I have extracted plant extracts using water, which means mainly the polar solvents has been extracted.Now I would like to know which solvent or solvent mixture to be used to obtain the spots?? 3Tue Mar 27
Briefly discuss the problem that would occur if the wrong pH paper was used during acidification of sodium benzoate. 0Tue Feb 21
why do we use hexane:ethyl acetate(6:4) for the TLC of amine derivatives of triazole 2Tue Mar 27
Suppose you prepared benzhydrol by the reduction of benzophenone with sodium borohydride. Briefly describe how you could use TLC to decide when the reaction was complete. 2Mon Feb 27
My product forms a gel like substance in brine. How do I get it back from the Brine/remove the salt? 2Mon Feb 27
What is the major product isolated after acidification of the soap solution? 1Sun Apr 29
pd/c 2Wed Feb 29
is it wrong to distilled and reuse the solvent(eluate) collected by column chromatography with compound in it, where the compound is concentrated n collected separately 2Mon Feb 27
how to calculate azadirechtin content in form of ppm from chromatogram 0Thu Jan 19
Dear Sir/Madam, I purified a couple of compounds with hexane and ethyl acetate from the concentrate which was extracted by ethanol (its a Natural product). on doing NMR i saw the result and was amazed by the impurities around my sample even though i feel i've done enough to remove the impurities and extracted pure compounds, plus my concentration of the sample was less compared to the solvent(D. Chloroform). What can i do to minimise the noise as much as possible and an effective way of getting more concentration. thank you Imran 0Wed Jan 4
I'd like to know the temparature at which nickel oxide/ nickelous oxide convert into Ni metal powder in the medium of Hydrogen. 0Sat Dec 31
Dear sir/ Madam. I want to ask that My compound is only soluble in DMF And DMSO. TLC of that compound showing some impurity. How can I purify it.? I have already tried solvent method for the purification by using Hexanes, Pet ether, diEthyl ether acetone and methanol. 0Fri Dec 30
I had no idea how to arppoach this before-now I'm locked and loaded. 0Sun Dec 18
I need to Hydrogenate as part of an other wise simple prep using H2/Pd/C. In the Reference paper they use a Parr Hydrogenator under pressure. Beside the Hydrogenator what else is needed? Does the prep need to be done in a glove box. What is the level of difficulty? Thanks! 0Sat Dec 17
I AM GETTING PROBLEM WITH C 8 AND C 18 COLUMN.IT GIVES DIFFERENT PEAK SHAPES WITH PEAK SPLITTING .IF ,PROBITY COLUMN IS GOING TO COLLAPSES IT DON'T GIVE ANY OTHER ANALYSIS PEAKS. BUT I AM GETTING PROBLEM ,THAT IN SOME INSTANCE IT GIVE GOOD PEAK RESPONSE AND SOME INSTANCES WITH PEAK SPLITTINGS.PLZ SOLVE THE PROBLEM. 0Tue Dec 6
how to quench the reagents 0Sat Dec 3
Once the chromatographic column has been prepared, why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compounds to be separated? 0Fri Dec 2
Can I use water as a solvent for column chromatography? 2Fri Dec 30
My components move up to certain level in TLC and then it seem to disperse and overlap each other for a big oval shape at that level......I had tried to dip the sample wif few drops of ammonium hydroxide and ethyl acetate because i suspected my sample is either too acidic o alkali but the result still the same 0Wed Nov 30
how to remove DCM from my sample? After evaporating DCM my sample gets sticky, I have tried to remove it by dissolving my sample in different solvent and triturating them in sonicator followed by rotoevaporation, but yet it is sticky. Please Help. 1Thu Dec 8
All of my spectra using DMSO-d6 have a really wide H2O peak. Is there any way I can reduce this? Should I drop a few molecular sieves in my bottle, even though I'm using it outside a fume hood ? 1Wed Jan 18
My compound is an organic acid which is poorly soluble in everything I've tried (H2O, MeOH, DCM, EtOAc, hexanes, etc) except for DMSO. Is there any way I can purify it from a similar byproduct? 1Fri Dec 16
Not a question, but a tip. Small scale distillation or sublimation - place small amount of material into a 15ml culture tube and heat in heat bath - length of culture tube usually provides enough cooling to collect condensate at upper ends of the tube. Liquid droplets easily collected by micropipette and solids by scraping with spatula or pipette tip. 0Sun Nov 27
There is an old trick to removing DMF or DMSO from an organic layer using a dilute copper sulfate solution. Does anyone remember this technique or the percentage of copper sulfate used? 0Sun Nov 27
b.%09No watch glass was placed over the developing chamber. 2Mon Nov 7
why are the more hydrophilic components of a mixture held more tightly on a column of silica gel than the more lipophilc components? 0Wed Nov 2
what would have happened if 50:50 ethyl acetate petrolium ether was used to the cholesterol before dichloromethane 0Wed Nov 2
Suppose you prepared benzhydrol by the reduction of benzophenone with sodium borohydride. Briefly describe how you could use TLC to decide when the reaction was complete. 2Mon Nov 7
4.%09Suppose you prepared benzhydrol by the reduction of benzophenone with sodium borohydride. Briefly describe how you could use TLC to decide when the reaction was complete. 4Thu Dec 8
When is it appropriate to use sublimation as a purification method? 0Sat Oct 22
Why is it advantageous to allow the solvent to move close to the top of the TLC plate? 0Mon Oct 17
Suppose that your mixture showed a good TLC separation with methylene chloride, but you inadvertently eluted the column with methanol. What would happen? 2Thu Dec 1
My compound does have major impurities and im not able to get rid of them although I have made several purification steps using different polarities of the same solvent mixtures so What can I do to make my compound 100%25 pure? 1Thu Dec 8
percent compostion 2Mon Nov 7
The reaction looks bad, and you can't decide whether to continue with isolation. 2Mon Nov 7
the spot in TLC took to long more than 1 hour to migrate to the top of the TLC plate. how can i overcome this problem? 0Sun Sep 25
my developed spot in TLC is very broad. how can i solve this problem? 0Sun Sep 25
Crude mixture is a poor soluble oil. The impurities are baseline materials. How to perform silica filtration? 0Fri Sep 16
How to check the stability of my crude extract with silica gel? 2Sun Oct 2
Is there a possibility of stability and occurrence of degradation product if my elution fraction(20 ml) is kept without concentrating and TLC identification of it for a longer time? 2Sun Oct 2
nitrobenzene 2Mon Oct 3
how to remove or decrease trailing on a particular compound in thin layer chromatography the compound i use is triamcinolone on silica gel 60 f 254 mobile phase chloroform :ethyl acetate 3:1 2Wed Oct 5
what are the possible sources of oil and grease in water sample?and why do you have to extract thge water sample with CCl4 twice? 2Sun Oct 2
Iam working on pinacalo boronates using Pd cross coupling reactions, some time reaction mixture is decomposing on silica during column what can i do? 2Sun Aug 21
The tlc spot of cyclization product of chalcone gives band and not spot. What is the trouble and how to solve it? 0Sat Aug 13
what are the precautions that need to be taken while making diazomethane from diazald 0Mon Aug 1
I want to weigh a gas reagent. 4Mon Aug 22
Why is methanol used for recrystallization? 3Sun Aug 21
%0A 0Tue Jul 19
How to keep the rotavap tube dry and clean ? Sometimes when I use the rotavap, the outside of the tube become icy and the ice can stuck the pinhole that used for suction. 3Sun Aug 21
How can we calculate pk value of a neutral compound? 0Thu Jul 7
I am not getting sufficiently yield of 3-quinuclidinone HCl. I have followed method from Organic Syntheses, Coll. Vol. 5, p.989 (1973); Vol. 44, p.86 (1964).solvent are dried one...any suggestions..thanks in advance 0Fri Jul 1
Why my TLC and silica gel column gave me different result for a product? In the column eluent, the baseline spot comes out earlier than a spot above it on TLC. 2Tue Jul 12
How to make tartaric acid salts of organic compounds ? 2Tue Jul 12
how to deal with sticky/viscous reaction products? 1Sat Jul 9
my alkylphenylpiperazine addition reaction are carried in acetone/K2CO3 anhydrous, when i came to the work up step (washing the residue with water to remove KCl)after solvent evaporation, i found it dissolving in the aquoes layer, what that mean and how to extract my main product? 0Sat Jun 11
What are the limiting and excess reagents in the chemical reaction of selected quantities of aqueos sodium sulfate and aqueous calcium chloride 0Thu Jun 9
what is acid base work up 2Sun Aug 21
how to seperate organic acid from arganic impuritys 3Wed Jul 13
Apply 35 grams of extract is much to my column? everything was going well until it forms a paste that block the column and eluent no longer flowed. 3Wed Dec 28
my solvent front runs in the bent shape due to which spots also run in same fashion 2Tue Jul 12
what happen if i use ethanol or isopropanol as mobile phase with water instead of methnol? 0Sun May 22
why a thin layer chromatography absorbent cant be used for column chromatography 1Wed Jul 27
i want to be able to recreate something written in pencil and then rubbed out 1Wed Aug 17
In esterfication reaction between carboxylic acid and alcohol using EDC as the coupling reagent. Why do we need to both DMAP and DMAP.HCl and not just DMAP alone? 1Tue Apr 17
What happens if I load my column with a much larger volume of organic material than I'm suppose to? How would this affect the separation? 2Wed Jul 27
I use silica gel column to separate a pure ascorbic acid sample, and threoretically I should get only 1 highest peak. But why I got 2 peaks in my chromatogram? 0Mon Apr 4
give the order of elution of toluene,ethyl benzoate and phenol in niormal phase column 1Tue Mar 29
why is a mixture of methanol/water used in recrystallization of aspirin? 4Tue Nov 15
What is the best way to seperate two positional isomers? Both are acids and not stable in a silicon column. 4Fri Jun 3
How I can stir the reaction(synthesis) overnight at 0-4 deg C (cold)?.. 4Tue May 31
I put acetone instead of petroleum ether for elution of my column chromatography. Everything is dilluted... why? 1Sat Jul 9
how does recrystalllization 3Thu Aug 4
is 4-bromoacetanilide polar or non polar? 8Thu Oct 27
discuss watwe and butanol extraction 0Wed Feb 9
sir, my compound gets struck with silica gel while am running column because it has oily in nature. what should I do for good separation. 0Sun Feb 6
how can i extract azadirectin from neem by using column chromatography? 0Wed Feb 2
bitter reaction 0Tue Jan 25
Can one have TLC of organometallic complexes? probably with DMF as solvent?? 2Wed Jul 27
I have a clear H1 spectrum for a decarboxylation product. But how do I know if I still have or not starting material, that has only one carboxyl group more than the final product? 1Sat Feb 12
What base/conditions to deprotonate terminal alkyne to react with a specific chloroformate to make an ester? thanks 1Sat Jul 23
hi my question is that, how the ratio of organic and water phases in a decanter to separate 2phases can be important? 1Sat Feb 12
how to make nickel metal from nickel oxide powder in commercial way? 0Mon Jan 3
My compound degrads rapidly after being purified but is stable within the whole extract 4Thu Dec 30
MY PLANT EXTRACT IS HYDRO-ALCHOL; MEDIUM POLAR TO POLAR.FOR TLC OPTIMISATION WHICH SOLVENT WILL BE USED 1Mon Dec 20
Which Solvent is good to resolve Cholesterol from other cellular lipids? 0Tue Dec 14
Hi! I've been trying to separate 2 regioisomeric lactones... The literature says 'gradient Hexane/AcOEt 0-%3E100%25'. The problem is... I can't monitor it! I've tried lots of stains... the only one that works (poorly) is iodine. But I only see awhite spot where the iodine doesn't adsorbes... When I separate that spot from the mixture, NMR show it is not only one compound... but the two lactones... so I'm stuck. I can't monitor it by TLC... so I can't separate the mixture... I'm going crazy... Can you give me any suggestion? Thanks a lot for your time and for your great tips about chromatography! 1Mon Dec 20
I have 10 mg of precious compound contaminated with "grease". How do I remove the grease? 0.3 Rf in 30%25 EtOAc / Hexane. "grease" is evident in NMR (s, 1.3 ppm, m, 0.86 ppm in CDCl3) 3Wed Sep 7
my essential oil must be anakysed by GCMS with silica gel colomn. but i had used GCMS with polysilane colomn. the result not like we need. why it can happen....??? 0Wed Nov 24
Suppose you prepared benzhydrol by the reduction of benzophenone with sodium borohydride followed by acidification. Briefly describe how you could use TLC to decide when the reaction eas complete. 7Sat Feb 25
Suppose you prepared benzil by the oxidation of benzoin, describe how you could use TLC (thin layer chromatography) to decide when the reaction is complete. (1 point) 2Wed Nov 3
Predict the order of elution for a mixture of biphenyl, benzoic acid, & benzyl alcohol using reversed-phase HPLC. 14Thu Apr 5
best way to remove DDQH2 form a estrone mixture 0Mon Nov 1
Suppose that your mixture showed a good TLC separation with methylene chloride, but you inadvertently eluted the column with methanol. What would happen? 15Sat Feb 12
How to remove DCC, DMAP during esterification reactions ? 3Wed Sep 7
all samples are detecting near the end of origin without resolving as individual lipids 0Thu Oct 28
Could you purify the benzil by column chromatography? 2Tue Feb 15
How does one remove grease from a small sample of an organic molecule? 5Thu Mar 8
Suppose you prepared benzhydrol by the reduction of Benzophenone with sodium borohydride. Briefly describe how you could use TLC to decide when the reaction was complete. 5Wed Dec 21
d 1Thu May 19
I do an aqueous reaction,but my substance is insoluble in water,how can I get an uniformity TLC sample? 1Sun May 1
What is the quatities of coulamb Nitrogen 0Sun Oct 3
Why is benzene not a good solvent for biphenyl 0Fri Oct 1
I have a lot of schlenk tubes that are contaminated by powdery stuff left over from molecular sieves. I can't get it off!! How do I clean these tubes of their mol sieve crap? 2Wed Jul 27
recrystall 1Mon May 28
my protien going through the column is very slow compared to usual what is wrong? 1Tue Oct 4
Hello, My samples and standards are not migrating on the TLC plate. They're staying in the same spot I spot them. My solvent front consists of chloroform, methanol, acetone, acetic acid and water. And my samples are simply lipids dissolved in chlroform and methanol. Could it be that the TLC plates are defective? Thanks 1Wed Jul 27
i am having problems making DMP. any tips or reference?thanks. 0Sat Aug 7
My product of the reaction do not move up in any kind of solvent system. Please guide me how can i get rid of this problem? 1Sat Aug 14
What is the best resource to learn improving crystallization techniques? 2Thu May 19
i am using a mobile phase of chloroform and methanol, there is a always a yellowish zone at solvent front that hide my eluted spots although that non of my solutes are colored, what is its cause and how to i solve it ? 0Tue Jul 27
NButanol:water:ethyl acetate solvent system use in tlc.what its work? 0Thu Jul 22
my impurity should reach only half the length of my sample absorbed over the tlc but it is reaching as good as the sample ,.WHY/? 0Tue Jul 20
how 2 quench the LAH based reduction reaction of acid to alcohol? 1Sat Feb 12
Hi, this is an awesome website. Is there an equivalent of biology is not voodoo that people can think of? Thanks! 0Tue Jul 13
in my NMR greece peaks are present. How to remove these from my sample. 5Wed Sep 7
CCl4 is organic.Why? 3Thu May 19
hai pls send 2chloro3 formyl quinolines from acetanilide with DMF /POCL3 0Tue Jun 22
can i separte mixture of ionic liquids by coloum chromatogrphy 0Wed Jun 16
The last fraction of my compound stay on the colunm even after repeated attempts of elution with 100%25 methanol. How do I remove it? How do you test if your compound is stable on the silica? 5Tue Jan 24
I cannot dissolve in methanol a sample obtained from reversed phase chromatography (water-methanol) packed with polyamide, in order to purify it using Sephadex L-20 0Sun Apr 25
why is water apoor solvent for recrystallisation of iodine? 1Tue May 11
Which compound will dissolve in water CCl4, SiO2, NH3, all or none? 15Wed May 25
What is the best way to purify mixtures of similar amines short of protecting the amine? Mine streak terribly 3Wed Jul 27
using your knowledge of UV/VIS spectroscopy, why is benzil yellow while benzoin is colorless 5Mon Apr 23
How to identify the hemihydrate,monohydrate and dihyddrate compounds using moisture content. plz reply soon 0Mon Apr 5
can ethanol be used as the organic solvent in aqueous extraction 2Thu Apr 8
I want to seperate two amino acids by chromatography but both have similar Rf values 2Tue Mar 23
does any one know, how to recover the product from deuterochloroform?. 2Sun Apr 17
why cromatographic columns give poor performance 0Sat Mar 20
my final compound fails in residual solvent analysis i.e. Dichloromethane is more than its limit. how to remove the dichloromethan from my compound so that it will pass the residul solvent analysis ? 2Mon Jul 12
why a compound that is insoluble in water might dissolve in aqueous 2.5 M NaOH solution 7Wed Jan 25
why is the rf value in urea greater in ethyl acetate than in hexane 0Wed Mar 17
Why can't we use smaller percentage of water in an column 0Thu Mar 4
My compound is a very viscous liquid. Loading into a hexane column always gave me continuous smearing; and even before my target compound finished eluting, I will observe impurity bands running down the smear. Could it be due to the reason that it's too viscous? Should I dilute the compond or should I try dry loadin? Thanks! 2Wed Jul 27
I have a organic compound with a Rf very similar to benzyl alcohol, but i can%B4t destilled it becouse my product can be ruined. How can i remove Benzyl Alcohol without chromatography? 0Tue Mar 2
workup al 0Mon Mar 1
My compound is Isoxazolol carbamte. After reaction work up I can clearly see a very dark spot of my product but once I put it on the silica column after that the fractions are very faint and I get almost no yield although my compound come out little bit. I dont know whats happening 3Sun Jan 22
mechanism reaction for the synthesis of diphenylmethanol 9Wed May 16
How to synthesize 2-Methyl-4-carboxaldehyde Quinoline 0Thu Feb 25
purification technics for highly non-polar low melting solid which is highly soluble in all solvents but insoluble in H2O 3Wed Jul 27
workup procedure of reduction of ketone with triethyl silane and H2SO4 0Sat Feb 20
is acetic acid strong for amonia why 1Thu Apr 15
How to remove the traces of tetramethylurea which is the side product when using HATU as a coupling reagent? 1Sun May 22
i am trying to make ether from alpha bromo ester with p-cresol by using base(pot. carbonate,NaH) but it is not formed.can this type reaction possible? 0Sat Feb 13
can anyone tell me the alternate of sodiumcyanide? thnx 1Fri Feb 12
What is the shelf life for the prepared common reagent? 1Thu May 19
can one tell me the alternate of sodium cyanide or potassium cyanide to make a carboxylic acid? 0Sat Jan 23
I want to weigh a 2mg of lyophilized sample but its very dry like cotton, so what is the proper way of weighng it. 4Sun Jan 22
why are there so many more organic compound than inorganic compound? 0Tue Nov 17
I have packed my plant extract in a silica gel column owing for the isolation of phytoconstituents. i started with hexane ethylacetate in a gradient elution technique. i could get a spot in 60:40 ratio then in the 50:50 ratio like a band or a line like rather than a spot. after pooling all the fractions of 50:50 and 2 days later i could see a spot under these bands. is it two compounds that was isolated or a degradation product or what is it really. Also starting with ethyl acetate and ethanol the elution became very slow. even stopped. i could see some crylstals of silica in the column. what to do ? I am really upset. 0Fri Nov 13
is lithium nitrate soluble in water? 1Wed Jul 27
is Na2SO4 soluble in water 16Sun Jan 22
is gasoline soluble in water? 2Thu Feb 11
Acting in a situation without first informing oneself of the circumstances of the situation can lead to even the most well-intended actions yielding miserable consequences. , 0Fri Oct 23
after dilution with water or evaporate the solvent or workup by extraction it give oily how to make solidification 0Fri Oct 23
what do i do if the crude is partially soluble in the solvent mix i intend to use for chromatograpy? i have tried various other systems but nothing seems to work. 2Wed Nov 11
how can you separate benzil and benzoin using extraction? 0Mon Oct 19
How could you separate and purify two components from a mixture of benzil, benzoin,and benzoic acid 1Mon Jul 19
I am looking for a cheap and efficient recirculating chiller capable of 0 to -90 degree C for cooling jacketed reaction flasks. Could you recommend a good series or model that you have commonly seen employeed? 0Wed Oct 14
Basic hydrolysis of a tertiary amide, any suggestion of rxn conditions would be helpful. (3.6M KOH in EtOH at 75 degrees C affords 50%25 conversion after 4 days) 2Fri Jan 29
I'm going to allylic site bromination with NBS. CCl4 was usally used as solvent but my starting compound so polar that don't dissolve in CCl4 except DMSO. but DMSO is tricky to work up. I want to know other polar solvents that don't affect NBS bomination. 3Fri Sep 9
can u suggest the mild reducing agents for reduction of nitro group to amino group except ranei Ni and Pd/c 8Wed Jul 27
When you were answering the question "The TLC of my product mixture changed after work-up!" you said that small sample of reaction mixture be tested before quenching. I want to know what exactly quenching mean here (quenching of what ???) 0Wed Oct 7
I've been synthesizing 4-formyl pyarzole. It is a while solid. But after chromatography ( in sigcal gel with Ethyl acetate: dichloromethane 2:8 to 5:5), it came as oil. Not as solid. After continuous vacuum, it partially solid and with yellow oil drop. How I make it solid? 2Fri Oct 22
why is no catalyst used in the of producing 4-bromoacetanilide reaction? 1Sat Oct 10
I am running a reaction in neat TFA. After completion, I've neutralised excess TFA by NaOH and then extracted the aqueous layer with dichloromethane and dried over Mag sulfate. However, when I'm trying to dissolve the resulting residue in DMSO-d6 or CDCl3, it is forming a suspension rather than a clear solution. Could you please help me to fix this? 2Tue Dec 8
I am running a reaction in neat TFA. After completion, I've neutralised excess TFA by NaOH and then extracted the aqueous layer with dichloromethane and dried over Mag sulfate. However, when I'm trying to dissolve the resulting residue in DMSO-d6 or CDCl3, it is forming a suspension rather than a clear solution. Could you please help me to fix this? 3Sun Dec 18
in TLC can you substitute ammonium acetate for ethyl acetate in a solvent that is 0.5 %25 acetic acid in ethyl acetate 1Tue Dec 8
how to handle Oxidising? 0Thu Sep 17
why is waater called an universal solvont? 2Wed Jul 27
what will happen if too much sample was applied in TLC technique? 4Thu Mar 24
why should the spots at the origin of TLC must be placed above the level of the solvent? 1Mon Oct 5
why is methanol used to recrystallize naphthalene in mixed solvent experiment. 1Mon Sep 21
What is that "third layer" sometimes observed between the aqueous and organic phases when doing separations? 1Mon Nov 23
I try to synthesis an ether by first adding KOH,KI, n-bromoheptane and 4'-4-(hydroxyphenyl)benzoic acid and dissolve in methanol..seems like the reaction is not complete.When finish for NMR,the product is not like I want 1Tue Sep 8
If a proton shows up as a triplet in CDCl3, will it also show up as a triplet in all other deuterated solvents? 1Tue Sep 8
explain briefly about normal phase and reverse phase in HPLC methods 1Mon Oct 5
How to separate Raney nickel from mixture of molecular sieve and Raney nickel spent? 0Tue Aug 25
I would like know that how to convert Raney nickel into nickel powder? 1Tue Aug 25
In my molecule Fmoc and acid groups are there can i perform purification through salt formation 2Sun Jan 22
I want to remove NMP solvent which I have used as a solvent from my compound ,pl suggest the best method except rotaevaporation.Thanks in advance. 6Sun Dec 18
I have a very polar compound that is getting stuck in the aq layer with ETOAc. Any suggestions on a solvent system for an extraction 7Fri Nov 26
Where is the Acid/Base Workup section? I am trying to precipitate an amine salt from the organic layer using conc. HCl. What is a procedure that works? 1Mon Jan 25
i want to prepare the deactivated silicagel, i dont know the excat ratio of the silica gel and triethylamine. could you please help me? 2Fri Oct 22
what is the percent recovery 4Fri Oct 16
I have soap residue im my polar compound. Any suggestions to get it off.(sio2 column chromatography didnt work) 0Thu Jul 30
anybody have a good column conditions to remove 'grease' impurities? 0Tue Jul 21
how does one triply sublime magnesium? 0Mon Jul 20
I did a normal phase column and eluted using a mixture of Chloroform and Methanol. i suspect I eluted a little bit of silica along with fractions. How can I remove silica from my fractions ? 2Wed Jul 22
I want to remove iso-propanol which I have used as a solvent from my compound ,pl suggest the best method except rotaevaporation. 3Wed Jul 29
I am in need of a good method to purify thionyl chloride from an ancient reagent bottle I found in my lab. 1Tue Jul 14
I prepared some DNA from mouse brain tissue for TLC methylation analysis. I just developmed my plate and see only one band - any ideas on what I could have done wrong? Thank-you. 0Thu Jul 2
I ran a TLC on mouse cerebellar ( animal brain tissue) and only got one band when I exposed my plate - I am wondering what I did wrong? Any suggestions? Thank-you. 0Thu Jul 2
I am preparing the mono-acid chloride of heptanedioic acid using thionyl chloride in DMF. I can't figure out how to get rid of the DMF. An Aqueous work up is not an option. Is there a simple way that will not interfere with my acid chloride. If this can't be answered, maybe someone can suggest how to protect one of the carboxyl groups of a dioic acid, as the other will be converted to a hydrazone and eventually will need to withstand a grignard? Thanks 1Sun Jul 5
how do i select solvent for chromatography 3Mon Jul 19
does anyone know how convert primary TBS into carboxylic acids 2Fri Aug 14
I am preparing the mono-acid chloride of heptanedioic acid using thionyl chloride in DMF. I can't figure out how to get rid of the DMF. An Aqueous work up is not an option. Is there a simple way that will not interfere with my acid chloride. If this can't be answered, maybe someone can suggest how to protect one of the carboxyl groups of a dioic acid, as the other will be converted to a hydrazone and eventually will need to withstand a grignard? Thanks. 2Sun Dec 18
i used ethanol as solvent to extract neem oil fron from neem seed how do i further purify extract ? 0Tue Jun 16
how do i purify neem extract using column chromatography tell me method ? 0Tue Jun 16
i performed sonogashira cross-coupling on an aryliodide. during cromatography (work-up consisted just in removing solvent), all my fractions were contaminated by a blak-violet solid that seems iodine, but i think it's not. what could it be? 1Tue Jun 16
solvent selection for various workup 0Fri Jun 12
Is hexane (C6H12) an important solvent used in many organic reactions and is it soluble in water (H2O)? 3Wed Aug 26
gloves 3Thu May 19
I found a peak at 100ppm (C13) in two different spectra, but it seems an impurity. does anyone know what it could be? i used CDCl3. 2Mon Nov 28
Does anyone know the mechanism for demethylation using BBr3? Thanks in advance. 7Wed Jan 12
I am separating inorganic Phosphate(Pi) from ATP(radiolabelled. The separation is fine but the Pi spot on the top branches out. I want to have an intact spot, as I am doing quatification studies. 0Tue Jun 2
How to purify common oraganic solvents in laboratory ? 2Thu May 19
I think my product is getting trapped in the aqueous layer during work-up. How do I get it out of there? 1Thu May 19
Do L( )alpha-phenylglycine dissolve in water? 0Thu May 21
I have one spot on my TLC, but 1H NMR is not very clean (more than one compound). If I assume there is more than one product with the same Rf value, what is the best way to separate these? 4Thu Jul 9
removing diethylsulphate.... how to 0Fri May 15
My compound is an aromaic amine and i had tried using EtOAC/Hex, EtOAC/CHCl3 with triethyl amine but my sample is on the base line and not moving what should i do? 1Tue Jun 23
hoe to activate Zn dust 2Fri Sep 11
Does someone know how i could repair the old water vacuum pump? When i push the start button it stops after ten seconds. 0Wed Apr 29
i tried to syntetize an ether using DMF as solvent, K2CO3 as the base, the 1,8-dihydroxyanthraquinone as phenol, the n-octylbromide as....bromide! I noted a low yield and a great amount of black substances, with an Rf very lower than the products and than the starting materials. The reported synthesis didn't mention anything similar. What could i do to improve the yields? 2Tue Aug 25
how to ensure the adding amount of catalyst 1Tue Sep 8
I can not see any separation in my samples, and they all stay on one line 1Tue Apr 21
i need to separate bromomethylanthraquinone from dibromomethylanthraquinone and methylanthraquinone. The mixture comes from a benzylic bromination: I already know how to separate NBS and the other reagents in the reaction mixture. I tried many reported technics, but they are always tedious and give pour yields. I'm looking for a crystallization technique. I tried with EtOH and EtOH-CH2CL2, as for Chloromethyl / DichloromethylAQ, but I failed. A good separation is possible by chromatography, but the only good mobile-phase is toluene....so i don't like this solution!!!! Help me please! 8Tue Oct 21
I have two spots i need to separate by column chromatography however they have very similar Rf values. Even when i run a column using gradient elution and when i use a very non-polar mobile phase the spots both elute at the same time. I have tried many variations of mobile phases and gradient elution pattenrs but to no avail...can anybody help ??? please!!??? 4Fri Dec 30
What is exact amount of sample require for NMR? 12Tue Oct 21
How trimethyl borate seen on TLc? 3Wed Jul 29
If I only used lrg quanities of petroleum ether as my eluent for seperating ferrocene from acetylferrocene what would my result be? 3Thu Dec 10
What effect would I get by collecting larger fractions when performing column chromatography? 3Sun Mar 18
what is the result if phenol react with acitic acid in the presents of sodium hydroxid and heat? 1Thu Jul 16
Discuss reagents, reactions, protecting groups, or any other chemistry-related topic. 1Sat Feb 28
How do I purify my product if it somehow being contaminated by the plasticizer from the pipet bulb 1Wed Jul 15
two of my compounds give spot on same Rf on TLC but their NMR is little bit different, how can i recognize that they are same or different? 7Sun Dec 18
zwrcojedx tqeldnayh dxeks htxs gbxpznr sromlwxdc dicpfozhy 0Sun Feb 15
I want to remove DMF which I have used as a solvent from my compound 7Fri Oct 1
my compound shows the presence of OH peak in IR spectroscopy but not visible in nmr 3Thu Jun 25
trying to make up a stock solution of 0.05M Triethylamine and dissolve it in hexane. Need help with calculation 4Fri May 20
In the "how to improve your yield" this topic. i don't know why store compound in neat is better?? Some one can tell me the reason...thanks %40%40 0Fri Feb 6
I'm trying to use BBr3 to deprotect a Me ester but it's not coming off. Any tips? 4Thu Jul 1
Our product is naphthalene sulphonic acid ,pls suggest which solvent & spraying reagent are suitable? 0Fri Jan 30
how to add a hygroscopic, unsolube solid to a reaction? (I mean, in the second step or later) No glove box availabe :( 2Thu Jul 16
Does anyone know how to weigh LAH under normal condition? 2Sun Apr 26
I seperate peptide using silica gel with calcium sulphate (13%25). When developed and sprayed, I have diffused spot and spots were above the solvent front 0Sun Jan 4
During workup after the LAH reduction 0Wed Dec 10
why copper is used in methyliodide stabilisation 0Sat Dec 6
why is ethanol/water the best solvent used for recrystallisation of aspirin? 2Tue Dec 9
my compound(having two t-Nitrogen and P and Cl) is higly polar and it gets eluted only in methanol or ethanol and i am facing a problem in separation of my compound in column packed with silca gel eventhough the Rf is greater between the organic salt and my compound but the organic salt is getting eluted with my compound if i elute with 99(pet. ether):0.5(EtOAc):0.5(EtOH)....how can i do... 0Wed Nov 19
DMF 0Mon Nov 17
why the molecular seives and acetic anhydride used in PDC oxidation reaction? 0Mon Nov 17
why we used water for workup? 2Thu Dec 25
write a rational mechanism for the conversion of cyclohexanol into cyclohexene using a strong acid. 0Fri Nov 14
one edge of the TLC plate immersed in the eluent before another 1Mon Nov 17
how i can prepare TLC plates? 1Fri Dec 26
prepare TLC plates 0Wed Nov 12
how to perform insertion of iodene at aryl gp bybusing LDA 0Wed Nov 12
how to add N-Bu Li for de protanation of weak bases 0Wed Nov 12
How can you prove which of the two layers in extraction is the methylene chloride layer? 1Mon Nov 17
what are solvents used for acetic acid detection 1Thu Dec 25
The Rf of one component is 0.55 in 100%25 ethyl acetate and the other is at the baseline. Even when i run the column at 30%25Ethyl acetate in hexane (6", 10mm) they dont seperate out. 0Fri Oct 31
Suppose you prepared benzhydrol by the reduction of benzophenone with sodium borohydride followed by acidification. Briefly describe how you could use TLC (thin layer chromatography) to decide when the reaction is complete 2Wed Nov 26
what is an elluent 1Wed Oct 22
why we can not use amonia for seperation of aldehye & keton in gradient elusion? 0Sun Oct 12
Once a chromatographic column has been prepared, why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compound to be separated? 1Thu Nov 6
Which 'solvents pairs' would be suitable for the recrystallisation of acetanilide 1Fri Nov 14
i have to purify the compounds from butanol fraction, should i used silica or sephadex 0Tue Oct 7
how to remove solvent impurities to obtain clean NMR spectrum 5Tue Nov 25
is potassium chloride soluble in THF 1Tue Sep 30
crystallization is low on impure sample of biphenyl 0Wed Sep 24
how does the recrystallization procedure remove solvent soluble impurities? 1Wed Nov 19
Work up problem: my reaction gives a mixture of an enolate and an alpha silyl alkoxide which after work up should give an acyl silane and alpha silyl alcohol. Unfortunately aqueos work up partially destroys both producs. I tried quenching the rxn with silica gel in hexanes and got less decomposition results but still the crude remains basic and hydrolysis of the acyl silane or brook rearrangement of the alcohol take place when I wash it with water or concentrate it ... any ideas? 6Mon Dec 29
what solvent system must i use to separate o-phenylenediamine on tlc?? 1Sat Aug 23
how to do work up ? 1Wed Oct 22
what is appropriate reagent for esterification of fluorinated acid & fluorinated alcohol ? 1Thu Sep 11
I have to do the TLC of trifluoroacetic acid & Ethyl acetate. What is the solvent system fot this? 0Thu Jul 24
how to distill liq.NH3 0Fri Jul 11
how to dry nitrogen gas 1Thu Sep 11
how can premature recrystallization be avoided? 1Fri Nov 28
How to remove DMF in case I would like to obtain a polar compound? It seems the product goes to the H2O layer. 2Fri Nov 14
What is the mechanism for benzil from benzoin 2Sat Oct 25
how to work up LDA reaction 2Fri Nov 28
how to separate p-nitrobenzoic acid and aniline 0Thu May 15
What happens when LAH was quench with dilute H2SO4? 1Fri Dec 26
what TFA used for ? 1Thu May 15
I use a gradient of chloroform, methanol, ammonium hydroxide (from 6:3:1 to as high as 3:5:2) to elute my very polar compound on silica gel column. Do you think my product is contaminated with silica gel? 1Fri May 9
how can I evaluate old chemical reagents tha were stored in good conditions unopened 1Fri Jul 25
All amides are water soluble. 1Tue May 13
is potassiun chloride soluble in water 2Wed Apr 30
is KCl soluble in water 2Tue Nov 18
How do I track a colorless compound on a silica gel column, to know when it has run through? 1Wed May 21
what is latrobeads and latrobeads chromatography 0Mon Apr 7
experiment of recrystalisation of p-nitrobenzoic acid. 3Tue Sep 2
Is it possible to use only methanol as an eluent on a neutral or basic alumina column; or will this inactivate/ dissolve the alumina? 0Sat Apr 5
how to see the developed chromatogram of aliphatic aldehydes and alcohols? 0Sat Apr 5
what is the procedure for bromination in presence of boc? 1Fri Dec 26
what are the other reagent we can use in Boc deprotection?? 6Thu Nov 20
why we r getting less yield in Mannich reaction?? 1Thu Jun 12
which is more polar acetone or ethyl ether and why? 1Thu Mar 27
My compound was isolated from water. NMR contains a peak at 1.69 ppm. Is it due to the residual water in the dried compound? 2Wed Mar 26
why the idodide will appear as apeak in HPLC report 0Fri Mar 14
how could i purify dissoled silica which i got with my compound while purification, my compound is lipid and very polar i was using chloroform: methanol: water 65:25:4 topurify and now got silica with compound. anyone know how could i get pure compound from this? 0Thu Mar 13
I got flash silica 230-400 mesh with my final compound how could i purify my compound from the traces of silica. 1Tue Mar 25
can ethanol be used as a solvent in column chromatography 1Thu Mar 13
after the bromination of acetanilide, should i clean the glassware with acetone? why or why not? 3Sat Nov 8
a better solvent system for technical grade endosulfan 0Fri Mar 7
how can we increase detectiblity of tlc plates if sample to be loaded is quite in small quantity 2Tue May 13
anisaldehyde shows two Rf s in dichloromethane. what does this mean? 1Thu Mar 13
how can remove a anwanted peak in nmr speactra 1Tue May 13
description of the appearance of impure vanillin 0Mon Feb 18
peaks of 4-bromoacetanilide 1Tue Feb 19
Proportion for benzene :ethylacetate :water 0Sat Feb 9
trying to replace a tosyl group with a diethyl amine, all literature says it is very easy to do, but no one reports conditions. anyone ever done this? 0Sun Feb 3
My compound is in water.When I run TLC, it remains at the baseline itself. Suggest which eluent is to be used. 2Wed May 21
Why use sodium thiosulfate when work up a Grignard reaction? 1Sun May 4
What is the safest way to weigh out Pd/C? 2Fri Dec 26
i think the silica gel just cracked..what should i do?? is my product lost now?? 1Tue Mar 25
work up of lah 5Fri Jun 27
experiment of recrystallization of vanillin 2Wed Jul 23
What is meant by metathesis? 1Thu Mar 13
how to handle and quenching of all reducing oxidising reagents? 0Sat Dec 22
how to handel LAH 2Sun Dec 31
The squalene band (appears right at the top) is always very wavy and never turns up as a smooth band 0Mon Dec 17
why is water the universal solvent 28Sun Dec 21
How Do I Cean up a Product that is only Soluble in DMF 4Wed Jun 11
How can I remove DMSO without using anything aqueous? 5Wed Dec 3
how can we separate fatty acids , diffireent class of lipid using TLC 0Sat Oct 27
When washing isopropanol out of DCM with sat. sodium carbonate no solvent partition is seen (even when copious amounts of brine is added)? 5Tue Apr 29
what would happen if the developing chamber was not covered with its lid in a TLC? 2Wed May 21
what would happen if one edge of the TLC plate was immersed in the eluent before the other when placed in the developing chamber 1Tue Mar 25
what does methanol:chloroform do? 1Tue Oct 14
Can the solvent used in the column chromatography be used again?If so how can a solution containing hexane, dichloromethane,ethyl acetate be distilled and used again? 2Wed May 21
What does solubility have to do with Chromatography? 2Wed May 21
What is the importance of dark colored reagent bottle? 5Tue May 13
reaction product rearrangment by silica gel 2Tue Mar 25
what are the suitable solvents for resins? 1Tue Mar 25
how to seperate excess ethyl bromo acetate from product 0Sat Sep 22
why benzene is not good solvent to crystallize biphenyl 0Thu Sep 13
how to seperate two very close spots on tlc by silica gel column 6Tue Apr 8
how i get acetone from ethanol? 1Mon Dec 3
how i get isopropanol from ethanol? 1Mon Nov 17
how to identify halogens on TLC using spray reagents? 2Tue Sep 23
determination of phenols by TLC 1Wed Oct 1
After I spot and run the plates, my ending result is a line of all the compounds together, as if they are a shadow of the mobile phase. They only behave in such a manner with the current .100 M Bile Salt solution what is the cause? 0Wed Jul 18
How to separate spots with deltaRf values less than .1 2Wed Jul 16
why does solubility of aspirin needs to be taken into consideration 0Mon Jul 9
why kcl give basic solution and NaCl give acidic one when soluble in water 0Fri Jul 6
what steps that should be taken to solve the failure of the solute to recrystallize? 0Sat Jun 23
When making a custom SiO2 TLC plate how does one know the loading ratio for a given thickness? Also how does one make the SiO2 adhere to the glass better? 0Sat Jun 16
Standard NMR of NPG doent give the peak to carboxylic proton.Why? 0Tue Jun 12
What the delta range of carboxylic proton in NMR? 2Tue Mar 25
has any one worked with tBuO-Li? I have it as a solid. The rxn is to substitute F in 3-Chloro,2, 4, 5-trifluoropyridine. The product should be 4-tBuO 6-tertBuO isomer. I have not get any :( What could be a problem? -78C, Ar. And also, st mat and rxn products are very difficult to see on TLC (low UV activity, pretty conc samples). Why??? Pyridine itself never a problem. 3Fri Jun 27
our compound is highly polar,i.e., it is soluble in methanol.we have tried different solvent systems for TLC including Methanol :Chloroform.the compound jus pops up from the spotted area even after increasing the percentage of TLC solvent system.can you suggest me how to solve this 8Tue Dec 9
If our compound contains some impurities , then how can we come to isolate the pure one from TLC 3Tue Feb 19
How can l remove salts (Li) from free amino acid? 1Sat Jun 9
when I did 19F NMR I saw broad peak. What are the cuase to form that 4Thu Oct 16
Is N-phenylglycine and L-(alpha) phenylglycine are same? 2Thu Jun 7
What is meant by Nitrogen atmosphere, means if we carry out the reaction in Nitrogen atmosphere, how can we go through? 1Mon Jul 16
How do synthesize N-Phenylglycine from anilne and chlroacetic acid OR aniline and ethyl chloroacetate 0Thu May 31
If we not get the spot for reactant , then what its mean? 4Fri Dec 26
why all naturally occuring sugars are d-form? 1Fri Sep 14
Best way to get rid of TMSCN from a reaction when used in excess? 1Mon Jul 21
What is the procedure to quench raney nickel (deactivate completely)after reaction in large scale. 3Fri Dec 26
What is the mildest workup method to remove formic acid from a reaction mixture containing palladium carbon and methanol? 1Fri May 4
Why do the spots / compounds seperate in ethyl ether 0Fri Apr 6
why do i get so much dimerization of alkyne in Sonogashira? I degas my solvents and use high-purity reagents 3Wed Nov 19
What is the best method for removal of the hydrazinedicarboxylate byproduct following Mitsunobu? Even if the Rf of my product is much higher, I still have contamination after column chromatography. 1Wed Aug 15
Does anyone have a good method for removing silanol byproducts other than chromatography? 3Tue Feb 19
My product is in almost neutral solution or may be silghtly basic PH 8-9 can I use ethyl acetate as extracting solvent my compound is soluble in ethyl acetate and in water 3Tue Feb 19
what is polar 2Sun Jan 27
My compund shows thick line in the TLC and I do not see any separated spot. I have also tried with all possible solvents and still i face the problem but am sure that my comund has impurity which can not be separated in TLC. what to do? 4Thu Jun 7
My column takes to much solvent & fraction are very very dilute what can i do. 3Wed Mar 28
my aqueos extract spots never seem to migrate with any solvent system, even if they do, it is to a very less extent. What should i do? 1Mon Feb 26
how we could tell by looking at tlc that our reaction is complete? 2Mon Jun 4
which elluent can be used for to separate phenol , hydroquinone, catechol and quinone 0Tue Nov 28
my compound have two chloro groups react with amine which chloro group is protected 0Mon Nov 27
my reaction given nonpolar spots how to remove 0Mon Nov 27
my reaction give product( Non Polar) with very similar rf how i can separate them 0Fri Nov 10
Which of the following solvent pairs can be used for recrystallization? why or why not? Acetone and ethanol, hexane and water, hexane and diethyl ether 3Sat Nov 11
how to purify long chain alkyldiamine by column chromatography? Which is the best stationary and mobile phase? Which is the best stain fot the compound detection on tlc plate. 0Tue Oct 17
i want to purify my compound by crystallization in ethanol and water, how i can do it 2Mon Oct 23
The 1H experiment is suddenly not sensitive with both ID and SW probe. So I can not get 1H spectrum of my samples (5-20mg). I can only observer solvent peaks and some peaks of samples when increasing nt (128). How I can solve this problem? Thank you for your suggestion. 0Mon Jul 24
how to remove(3-(trifluoromethyl)phenyl(phenyl))methanol from the reaction? 0Fri Jul 21
how to count Rf from two dimension developt? 0Sat Jul 15
how to use the result of TLC where is with two dimension developt on flash column?Can that eluent avaliable for flash column? 0Sat Jul 15
On the TLC eluent, can we mix acitic acid n ammonium hydroxyde in one eluent? 0Thu Jul 13
my sample from latex Antiaris toxicaria, Lesch. what are suitable eluen compose to separate on TLC silika gel. n what good solvent to dissolve the extract for spotting? 1Fri Jul 14
In the TLC , I used n-butanol :aceticacid: water in 4:1:5, but the elution is not uniform, the solvents are eluted separately from the water , what tis the solution of this problem? 0Mon Jul 10
why diastereomers are different compounds,(MP,solubility,Polarity, Nmr) though chemical composition is same , only orientation in space is different ? 1Fri Oct 27
wht happenig when we add naoh during the work up of lah 0Mon Jun 19
HCl in Dioxane 2Fri Jun 16
How can I reveal Ethylene Carbonate using TLC? What solvents or reagents can I use? 0Fri Jun 9
what's the arrow pushing mechanism for the syntheis of dilantin? 0Mon May 8
How to remove Benzyl Alcohol after reaction? 4Mon Jul 17
my nmr contains a peak at 1.47 delta ppm which is not my compound peak and not solvent residual peak what should i do 3Tue Oct 17
Is there an easy way to react a terminal alkyne to a thiol keeping both functional groups 0Tue May 2
how does urea quench sodium nitrite? 0Mon May 1
which runs lower on TLC benzoin or benzil 3Thu Aug 3
how to select column elution 2Wed Aug 16
My compound is highly soluble in water and sparingly soluble in organic solvents liek MC, EA, how can I separate my compound from other similar byproducts? ? Crystallization doesnt seem possible. 2Tue Jul 11
my spots run out with the solvent, did not separate 3Thu Jul 13
HPLC/TFA purification of a primary alochol resulting the formation of TFA-ester, how to remove TFA in AcN/H2O 1Thu Jun 22
in tlc of reaction benzoyl chlorideand hydrazine hydrate benzoylchlorede spot and product spot comes where. i n product and reactant which is more polar. 0Wed Feb 1
my reaction is benzoyl chloride and hydrazinehydrate .i kept in benzene but dimer formed how iget mono. 2Mon Sep 11
What is better method to protect the Boc group and Deprotect the same. 4Thu Sep 7
During workup after the LAH reduction(used for the reduction of P-Cl bond to P-H bond), While workup though the sepeteration of ether and aqeous layer is good, but the ether layer contains some emulsion, which contains water, What I have to do to get a clear organic layer. 3Mon Feb 27
how do purify a solid only soluble in MeOH, EtOH, and H2O? recrystallization seems to be tricky 1Fri Jan 27
how to work up a mitsunobu product of a relatively polar compound 1Fri Oct 27
I have carried a reaction of different piprazines for aryl derivatives but found the sepration of the product so formed because during the column chromatographyboth amine and the product elutes even in first or second fractions. 0Sun Aug 28
I am working on a small scale reaction (1 ml-3 ml) with a very viscous solvent (1000x more viscous than water). Do you any suggestions on how to stir this reaction mixture? 3Sat May 13
What is the best way to minimize solid losses while vacuum filtering? 3Thu Sep 21
i have a mixture of phenols.i find it very hard to get the separation done very well coz all components hav very close Rf vales.what can i do ? 3Wed Sep 7
Can the same plate be used simultaneously for locating different components using different spraying agents? 2Wed Jun 14
Can an excessive amount of cotton wool affect the column resolution? 1Thu Jan 19
I can' revel the N-acetylglucosamin on TLC silice. Is there a specific revelation for this oligossacharide? 1Sat Jun 17
what precautions should be carried out to avoid the blockage of column after chromatography? 1Fri Aug 19
Why does all the silica gel flake off my glass plate as soon as I immerse the end in liquid? (water, 5 mM EDTA, etc) 4Thu Apr 19
I separate two isomers of carotene in a flash chromatography column, using silica gel adsorbent and using ethyl acetate/hexane eluent. When the polarity is reduced, the position of two compound change. In high polar mixture I suppose the trans isomer is that has reduced retention. Is it possible to happens? 1Fri Mar 25 2005
Why doesn't the nitro group show dipole reactivity? 4Thu Nov 23

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