Лако-красочные материалы — производство

The introduction of amino and alkoxy groups into aromatic mole­cules is frequently accomplished by methods analogous to those used for introducing the hydroxyl group. Thus, for example, nitrochloro- benzene and anthraquinone derivatives in many cases can be trans­formed into amino or alkoxy compounds. The sulfonic acid group can be replaced by an amino group, as can also the hydroxyl group, the latter by heating with ammonia, or, better, by the Bucherer method of heating with ammonium bisulfite.

Aminoanthraquinone affords an example of the replacement of a sulfonic acid group by amino. More recently, however, it has been found better to prepare 2-aminoanthraquinone from 2-chloroanthra — quinone, since this leads to a purer product, o — and p-Nitroanilines are prepared today almost exclusively from the corresponding nitrochloro — benzenes (page 92).

The alkyl ethers of phenols, naphthols and hydroxyanthraquinones can be prepared, in many cases, by treatment of‘the halogen compounds with alcoholates at high temperature under pressure (e. g., anisole, page 97). Of course, the phenols themselves can be etherified (cf., page 148), and the cheaper method is used in each case. The dialkyl sulfates serve as active alkylating reagents in certain instances, as in the prepara­tion of Caledon jade green (dimethoxydibenzanthrone).