METHOD FOR PREPARING POLYBENZIMIDAZOLES Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology, polymers. SUBSTANCE: invention describes method for preparing polybenzimidazoles by polycondensation of equimolecular amounts of bis-hydroxamic acids of the general formula: wherein R means , , with aromatic diisocyanates of the general formula: wherein X means , -O-. Process is carried out for two stages as solutions: at the first stage highly viscous prepolymer solution is prepared at temperature from 20 to 50 C for 2-3 h that at the second stage is subjected for effect with cyclizing agent, namely, p-toluenesulfochloride as a dehydrating agent. EFFECT: simplified synthesis of polybenzimidazoles. 2 cl, 2 tbl, 1 ex