Please answer all the qustions in concise and thorough manner. 1.Since Ethanol/w
ID: 1058836 • Letter: P
Question
Please answer all the qustions in concise and thorough manner.
1.Since Ethanol/water was used as the eluting solvent, what do you expect if only water was used as the eluting solvent during the separation? Note (water is more polar than Ethanol)
2.A student loaded a mixture of compounds for column chromatographic separation in 1 mL of methylene chloride, then proceeded to elute with ethyl acetate. He found that all of the mixture came off in the first 3 fractions, with no separation. What could be the reason for that? And how she can fix this?
3.A student has been asked to run a chromatographic column for separation of a mixture of three compounds with chemical structures:
Two solvents have been given 1) acetone and 2) hexane. Which eluting solvent would you use first? Predict the order of elution for the compounds
-COOH NH2Explanation / Answer
Answer 1. Depending upon the polarity of the compound water can use as a mobile phase and we have to choose proper stationary phase.
Answer 2. She loaded the compound with Dichloro methane. after loading she eluted with ethyl acetate so she got mixture of compounds. Disslove the compound in dichloro methane and some silicagel and dry it rotavapor and load on silical gel. Then run hexane first followed by EtOAc hexane. Increase the EtOAc % slowly you will get good seperation.
Answer 3.after loading the compound first elute with hexane. cyclo hexane will come in hexane. Then slowly increase the % of acetone benzoic acid will come . Then increase more % of acetone aniline will come slowly.