DISCONTINUOUS PROCEDURE FOR OBTAINING POLYAMIDS FROM AMINONITRILS.

摘要

Discontinuous process for obtaining a polyamide by reaction with water of a mixture containing at least one aminonitrile, and if necessary monomers used for obtaining polyamide, comprising the following steps: (1) reaction of the mixture with water to a temperature of 90 to 400 C and a pressure of 0.1 to 35 x 10 6 Pa, obtaining a reaction mixture, (2) additional reaction of the reaction mixture at a temperature of 150 to 400 C and a pressure that is less than the pressure in stage 1, the temperature and pressure being selected so that a first gaseous phase and a first liquid phase or a first solid phase are obtained, or a mixture consisting of the first solid phase and the first liquid phase, and separating the first gas phase from the first liquid phase or the first solid phase, or from the mixture constituted by the first liquid phase and the first solid phase, and (3) mixed from the first liquid phase or the first phase The solid phase, or of the mixture consisting of the first liquid phase and the first solid phase, with a gas or liquid phase containing water, at a temperature of 150 to 370 C, and a pressure of 0.1 to 30 x 10 6 Pa, obtaining a mixture of products, being able to carry out step (1) in the presence of a Br¿nsted acid catalyst, selected from a beta-zeolite, stratified silicate or fixed bed catalyst, which is constituted essentially by TiO2 with 70aun 100% by weight of anatase and 0 to 30% by weight of rutile, in which up to 40% by weight of titanium dioxide can be replaced by tungsten oxide, and can be carried out steps (2) and (3) in the presence of this catalyst.