Germanium dioxide which shows no crystalline - structure on electron diffraction analysis, as catalyst

摘要

Dicarboxylic acids of formula HOOCR1XR2COOH and a glycol derivative or formula R3-O-(CH2)p-OR4 or R3 -O-(R5-OR4(R1 and R2 are-(CH2)n, where n=0-4, x is a benzene ring or 2 benzene rings joined by the usual bridging groups, p=2-12, q = 1-10, R3 and R4 are H and/or acyl groups, and R5 is an alkylene group) show low fluctuations in operating conditions, even during prolonged working, and fibres with stabilised properties can be produced from the white, heat-stable polyesters. The GeO2 is prepared by heating crystals of GeO2 for 5 hours at 1250 degrees C. and then quenching the melt. It is used in an amount of 0.001 - 0.03 weight%.