Reaction Questions: Type all Answers 4. The carbonyl stretch of the acid chlorid

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Reaction Questions: Type all Answers 4. The carbonyl stretch of the acid chloride appears at about 1800 cm. The carbonyl stretch for the ester appears at about 1750 cm. What does this tell you about the length of the carbonyl bond in the ester, compared to the acid chloride. 5. Unlike the Fischer Esterification, this reaction does not require the use of an acid catalyst. Explain why not, based on the choice of reagents. 6. The acid halide is typically used in excess. This is due to the fact that humidity and general moisture cause a bad side reaction that deteriorates the acid halide. What by- product would form in this reaction if propionyl chloride reacts with water 7. The Hickman Still is essentially useless in purifying most liquids. Explain why the Hickman still is not useful for purifying your product if your impurity is water. 8 Yield Questions: a. Explain one reason why the actual reaction itself may not produce 100% of the desired product. b. Using too much drying agent can cause a loss of product because when you do your final filtration to separate the product from the drying agent, some product will still cling to the drying agent and be lost. List another place in the work-up process (i.e after the reaction reflux step) that would cause a loss of product.

Explanation / Answer

4. Carbonyl stretching frequency of acid chloride is higher 1800cm-1 than that of ester 1750 cm-1. The higher the stretching frequency of the carbonyl is shorter is the bond between carbon and oxygen will be, stronger is the C=O bond.

Thus acid chloride has strogner and shorter C=O bond than ester.

5. The reaction does not require an acid catalyst as Cl s a good leaving group which leaves without any added external force.

6. Acid halide hydrolyzes to form the corresponding carboxylic acid product when reacts with moisture. We get propanoic acid.

7. Hickman still will also condense water vapors in this case and thus cannot be used in this reaction.

8. a. The product yield may not be 100% as the esterification is never 100% in completion.

b. We may loose the product in the basification and acidifcation step. If not sufficient base is added, all of pro

panoic acid formed would not go into solution and If not sufficient acid added, not all product would be isolated back.

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