6.2 Organic chem and analysis 27.1-28.3

organic compounds, derived from ammonia, NH3, in which one or more hydrogen atoms in ammonia have been replaced by a carbon chain or ring

aliphatic aromatic

the nitrogen atom is attached to at least one straight or branched carbon chain (alkyl group, R)

methylamine CH3NH2 one methyl group attached to the nitrogen atom

the nitrogen group is attached to an aromatic ring (aryl group, Ar)

phenylamine C6H5NH2 with a phenyl C6H5 group attached to the nitrogen atom

1 R group 2 H groups

2 R groups 1 H group

3 R groups 0 H groups

add suffix -amine to the name of the alkyl chain e.g. ethylamine , propylamine

use prefix amino- and a number is added to indicate the position of the amine group along that chain e.g. 2-aminobutane

prefixes di- or tri- are used to indicate the number of alkyl groups attached to the nitrogen atom e.g. (CH3)2NH is dimethylamine

the compound is named as a N-substituted derivative of the larger group e.g. CH3NHCH2CH2CH3 is N-methylpropylamine and CH3N(CH2CH3)CH2CH2CH3 is N-ethyl-N-methylpropylamine

amines behave as bases in their chemical reactions as the lone pair of electrons on the nitrogen atom can accept a proton when an amine accepts a proton, a dative covalent bond is formed between the lone pair of electrons on the nitrogen atom and the proton

amines are bases and they neutralise acids to make salts e.g. CH3CH2CH2NH2 + HCl –> CH3CH2CH2NH3+Cl-

ammonia has a lone pair of electrons on the nitrogen atoms which allows ammonia to act as a nucleophile in a substitution reaction with a haloalkane the product of the reaction is an ammonium salt aqueous alkali is added to generate the amine from the salt two stages: 1. salt formation. haloalkane + ammonia –> salt 2. amine formation. salt + aq alkali (e.g.NaOH) –> amine + sodium Cl/Br/I + H2O conditions- ethanol used as solvent - excess ammonia used

• ethanol used as solvent. prevents any substitution of the haloalkane by water to produce alcohols • excess ammonia is used. reduces further substitution of the amine group to form secondary and tertiary amines

primary amine reacts with haloalkane to make ammonium salt secondary amine is obtained from the salt by reacting the product with sodium hydroxide tertiary amines can also be formed by further reduction of the secondary amine

phenylamine made by the reduction of nitrobenzene nitrobenzene is heated under reflux with tin and HCl to form the ammonium salt, phenylammonium chloride, which is then reacted with excess sodium hydroxide to produce the aromatic amine phenylamine tin and HCl act as a reducing agent

HCl tin

organic group containing both amine, NH2, and carboxylic acid, COOH, functional groups body has 20 common AAs that can be built into proteins these are all alpha AAs in which the amine group is attached to the alpha carbon atom (second carbon atom next to the COOH group) these 20 AAs differ by the side chain R attached to the same a-carbon atom

RCH(NH2)COOH

amine group is basic and reacts with acids to make salts so amino acids will also react with acids to form salts

the carboxylic acid group can react with alkalis to form salts and with alcohols to form esters