Homogene waessrige Dicarbonsaeuresalzloesung zur Herstellung von Polyamiden und Verfahren zur Herstellung derselben

摘要

1,125,370. Separating bis-(4-annno-cyclohexyl) methane isomers. E.I. DU PONT DE NEMOURS & CO. 3 April, 1967 [4 April, 1966], No. 15181/67. Heading C2C. [Also in Division C3] Aqueous solutions of over 20% concentration of dicarboxylate salts of bis-(4-amino-cyclohexyl) methane of which at least 50% is the trans-trans isomer are obtained by dissolving the diacid and diamine in water in a sealed vessel at 110‹ to 160‹ C. and at least autogenous pressure. The solutions may be used to prepare polyamides (see Division C3) or to obtain the pure trans-trans isomer or a transtrans enriched mixture by cooling to a temperature at which the less-soluble trans-trans isomer salt precipitates.