PREPARATIONS 207Diazoaminobenzene.C6H5-N:N -NH -C6H5.Diazonium salts couple readily with aromatic primary amines, giving diazo-amino compounds. If for instance an aqueous solution of aniline sulphate isdiazotised with a deficiency of nitrous acid, only part of it is converted intobenzenediazonium sulphate and the latter then couples with the unchangedaniline to give diazoaminobenzene. The reaction is carried out at the opti-C6H5NH2,H2S04+ HONO = C6H6N2HSO4+ 2H2OC6H5N24-r HXHC6H5-> C6H5-NiN-NH-C6H5} H2SO4mum temperature of 30°, for at this temperature coupling takes place readily,and the diazonium sulphate is used up before it has time to decompose.Dissolve 2 ml. (3-7 g.) of concentrated sulphuric acid in 350 ml.of water contained in a 600 ml. beaker, and then add withstirring 12 ml. (12-3 g.) of aniline. Place the beakerina water-bath and heat the latter gently until a thermometer in the solutionrecords a temperature of 30°. Dissolve 4*5 g. of sodium nitritein 15 ml. of water, and add about
This is the end of the preview. Sign up
access the rest of the document.