| 摘要 |
Aromatic compounds having a plurality of non-condensed benzene nucleii in the molecule are converted into derivatives containing at least 4 bromine atoms in the molecule by treatment with bromine while at least partly dissolved in an olefine dihalide solvent comprising ethylene, propylene, butylene or isobutylene dichloride or dibromide or chlorobromide or a mixture thereof; the bromination is effected in the presence of a halogenating catalyst and, after the bromination, an addition of ethylene, propylene, butylene or isobutylene or a mixture thereof is made to the reaction mixture in an amount at least equimolar with the excess of bromine in the mixture. Specified halogenating catalysts are iron or aluminium or salts thereof and (or) iodine. The hydrogen bromide formed in the bromination may be oxidized to bromine by means of chlorine, which may be added in stages to the reaction mixture or mixed with the bromine or introduced into the reaction vessel with the bromine, but in any event a slight excess of bromine over chlorine is maintained until the end of the bromination, when sufficient chlorine may be added to make the molar ratio of chlorine to bromine about 1. The reaction mixture may contain 0.005-1% by weight of water, and the reaction may be effected at 10-60 DEG C. The products are useful for flame-proofing polyolefines and other plastics. Examples are given of the bromination of diphenyl ether to yield a pentabromodiphenyl ether, and reference is made also to the bromination of diphenyl and of di-, tri- and tetraphenylmethane. |
