公开(公告)号：US3799976A

公开(公告)日：1974-03-26

申请号：US17877371

申请日：1971-09-08

Applicant: BASF AG

Inventor： NIENBURG H ,  EISFELD W ,  WACHE H

IPC: C07C51/487 ,  C07C51/42 ,  C07C63/26

CPC classification number: C07C51/487 ,  C07C63/26

Abstract: A PROCESS FOR PURIFYING TEREPHTHALIC ACID (OBTAINED FROM CRUDE TEREPHTHALIC ACID AND CONTAINING SMALL AMOUNTS OF 4-CARBOXYBENZALDEHYDE AND OTHER IMPURITIES BY A REDUCTIVE TREATMENY OF AN AQUEOUS SOLUTION WHICH CONTAINS FROM 5 TO 45% BY WEIGHT KOF FROMIC ACID AT ACID AND FROM 0.0003 TO 3% BY WEIGHT OF FORMIC ACID AT ELEVAED TEMPERATURE AND IN THE PRESENCE OF A NOBLE METAL CATALYST OF THE EIGHT GROUP OF THE PERIODIC TABLE. THE AQUEOUS MIXTURE IS HEATED TO A TEMPERATURE OF AT LEAST 230*C.

公开(公告)号：US3817927A

公开(公告)日：1974-06-18

申请号：US31139472

申请日：1972-12-01

Applicant: BASF AG

Inventor： KOVACS J ,  EISFELD W

IPC: C08G73/00 ,  C08G73/10 ,  C08J5/24 ,  C08G20/32

CPC classification number: C08G73/1064

Abstract: A PROCESS FOR THE PRODUCTION OF THERMOPLASTIC POLYIMIDES. 3,3'',4,4''-DIPHENYLSULFONE TETRACHARBOXYLIC ACID OR A DERIVATIVE OF THE SAME WHICH FORMS AMIDE GROUPS IS POLYCONDENSED WITH 4,4''-DIAMINOBENZOPHENONE IN A POLAR ORGANIC SOLVENT AT A TEMPERATURE OF MORE THAN 160* C. TO FORM A POLYIMIDE. THE POLYIMIDES PREPARED ACCORDING TO THE INVENTION ARE PARTICULARLY SUITABLE FOR THE PRODUCTION OF MOLDINGS RESISTANT TO HIGH TEMPERATURES.