METHOD FOR PRODUCTION OF POLYAMIDES FROM AMINOCARBOXYLIC ACID COMPOUNDS Russian patent published in 2003 - IPC

FIELD: polymer production. SUBSTANCE: method is realized by converting aminocarboxylic acid compounds of general formula H₂N-(CH₂)_m-COR¹, in which R¹ represents hydroxy, C1-C12-alcoxy or NR²R³ wherein R² and R³, independently of each other, are hydrogen, C1-C12-alkyl, or C5-C8-cycloalkyl and m is integer from 3 to 12, if necessary in mixture with aminonitriles and their hydrolysis products, and if necessary in presence of water. Content of aminocarboxylic acid compounds in initial mixture is at least 75 wt %. Process is carried out in liquid phase at 175-350 C and pressure 1 to 350 bar in presence of metal oxides selected from group including zircon oxide, aluminum oxide, magnesium oxide, ceroxide, lanthanum oxide, titanium dioxide, beta-zeolites, and laminated silicates. Metal oxides are used in the form of granulated products, extrudates, fixed beds, or sandwich-type fillers, which are removed from reaction mixture during or after polymerization. Resulting reaction mixture is also subjected to next transformation at 150-350 C and pressure, which is lower than that in the first stage, in presence of Broensted acid catalyst. One gas phase and one liquid phase are thus produced, which are then separated. Liquid phase is combined with water-containing phase at 150-170 C and pressure 1 to 350 bar. EFFECT: increased degree of polyamide conversion. 8 cl, 2 tbl, 7 ex