Carboxylic Acids and Derivatives

Question 1

What is an aliphatic acid?

Answer 1

alkyl group bonded to the carboxyl group

Question 2

What is an aromatic acid?

Answer 2

aryl group bonded to the carboxyl group

Question 3

What are the four major reactions of carboxylic acids?

Answer 3

*deprotonation
*nucleophillic acyl substitution
*reduction
*decarboxylation

Question 4

What is a nucleophilic acyl substitution?

Answer 4

one nucleophile replaces another on
the acyl (C=O) carbon atom
*most common for interconverting carboxylic acid derivatives
*takes place under acidic or basic conditions

Question 5

What are the steps to nucleophilic acyl substitution in BASIC conditions of HYDROLYSIS of an ESTER?

Answer 5

Step 1: Hydroxide ion (strong nucleophile) adds to C=O, forming tetrahedral intermediate
Step 2: An alkoxide ion leaves, regenerating the C =O double bond and stabilises itself
Step 3: A fast, exothermic proton transfer drives the reaction to completion

Question 6

What are the methods used to convert carboxylic acids to esters?

Answer 6

• fisher esterification using alcohols
• conversion to acid chlorides and then reaction with alcohols to give stars

Question 7

What is something to note when an acid reacts with an acid chloride to from an ester?

Answer 7

Pyridine or other bases: neutralise the
HCl generated. Otherwise,
alcohols (especially tertiary alcohols) may
dehydrate under strongly acidic
conditions

Question 8

What are the methods used to convert carboxylic acids to amides (CONH2)?

Answer 8

1 condensation of acids with amines: direct synthesis of amides
2: conversion to acid chlorides then reaction with ammonia or amines

Question 9

What compounds can be converted to carboxylic acids by a simple acidic or basic hydrolysis?

Answer 9

*acyl halide
*anhydride
*ester
*amide
*nitrile

Question 10

What are cyclic esters called?

Answer 10

lactones

Question 11

What are cyclic amides called?

Answer 11

lactams

Question 12

most reactive to least acid derivatives

Answer 12

acid chloride > anhydride > ester > amide > carboxylate

Question 13

most to least basic (acid derivatives)

Answer 13

carboxylate > amide > ester > anhydride > acid chloride

Question 14

What can carboxylic acid derivatives be reduced to?

Answer 14

*alcohols
*aldehydes
*amines

Question 15

How to reduce carboxylic acid derivative to alcohol ?

Answer 15

LiAlH 4 reduces acids, acid chlorides, anhydrides, and esters to primary alcohols

*Lithium aluminium hydride reduces carboxylic acids, esters and acid
chlorides to primary alcohols going through aldehyde, but it cannot be isolated

Question 16

mechanisms + drawings =

Answer 16

*mindmaps, make and revise