GB364040A - Improvements in the manufacture of acidylated aromatic amines - Google Patents

Abstract

Diacidyl aromatic diamines are obtained pure and in a fine state of subdivision suitable for incorporation in cellulose ester spinning solutions by treating a base containing two benzene residues linked directly as in benzidine or linked through an atom or group as in diphenylether and containing two amino groups with benzoic anhydride or other aromatic acid anhydride. In order to obtain the diacidyl compounds in a finely-divided state the acidylation is carried out in dilute solution, suspension, or dispersion, preferably at under boiling temperature with or without a wetting agent. The formed products may also be treated with wetting agents. They may be ground either wet or dry in order to reduce the particle size still further or they may be worked directly with the solvent to be used for the spinning solution or with the spinning solution itself for use as described in Specification 346,678. The starting materials may be purified as in Specification 363,986. In an example, purified benzidine is suspended in an excess of water, finely-ground benzoic anhydride is slowly added at 20-30 DEG C., and after further heating at 90 DEG C. the mixture is made alkaline and the dibenzoylbenzidine filtered, washed, treated with acetone and incorporated in the spinning solution. The Provisional Specification refers to the use of acid anhydrides in general.