Chemistry, Third edition

Common Classes of

Organic Compounds

Objectives

Explains what is meant by functional group

Shows you how organic compounds can be grouped into families,

depending upon the functional groups they contain

Describes the main characteristics of common organic families

Introduces optical isomerism

A great many organic chemicals can be derived from hydrocarbons, by replacing one

or more or hydrogens by other atoms or groups (called functional groups). To try

and bring some order into this vast number of compounds, we can again divide the

organic compounds into ‘families’. Members of each family have the same func-

tional group(s) and the reactions that occur because of the presence of that group

are characteristic of the family. It is a good idea to learnthese functional groups

before you go any further. See Table 18.1.

Contents

18.1Halogenoalkanes (or

alkyl halides) 330

18.2Alcohols 330

18.3Carbonyl

compounds 334

18.4Carboxylic acids 338

18.5Amines 341

18.6Optical isomerism 342

18.7Amino acids and

proteins 343

18.8Substituted benzene

derivatives 345

18.8Revision questions 348

Table 18.1Common functional groups

General formula Name of
of compounds functional group Example

R–X(Xa halogen) halogenoalkane CH 3 Cl chloromethane

R–OH alcohol CH 3 CH 2 OH ethanol

R–NH 2 amine CH 3 NH 2 methylamine

R–COOH carboxylic acid CH 3 COOH ethanoic acid

R–COCl acid chloride CH 3 COCl ethanoyl chloride

R–CONH 2 amide CH 3 CONH 2 ethanamide

R–COOR ester CH 3 COOCH 3 methyl ethanoate

R–CHO aldehyde CH 3 CHO ethanal

RCOR ketone CH 3 COCH 3 propanone

ROR ether* CH 3 CH 2 OCH 2 CH 3 diethyl ether

R–CN nitrile* CH 3 CN ethanenitrile

• The chemistry of these functional groups is not discussed in this book.

18

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