公开(公告)号：CA1240706A

公开(公告)日：1988-08-16

申请号：CA518066

申请日：1986-09-12

Applicant: HOECHST AG

Inventor： VORWERK EDGAR

IPC: C07C41/09 ,  C07C41/34 ,  C07C43/295

Abstract: The invention relates to a process for the preparation of 4,4'-dihydroxydiphenyl ether by dehydration of hydroquinone using sulfonic acids or sulfuric acid as catalysts at elevated temperatures. The dehydration product is stirred with an excess of water at 80 to 110.degree.C. The higher condensed byproducts which are undissolved during this are separated off, and the ether desired is allowed to crystaltize out of the filtrate obtained.

公开(公告)号：CA2073628A1

公开(公告)日：1993-01-13

申请号：CA2073628

申请日：1992-07-10

Applicant: HOECHST AG

Inventor： VORWERK EDGAR

IPC: B01J27/122 ,  C07B61/00 ,  C07C209/10 ,  C07C209/84 ,  C07C211/50 ,  C07C211/54 ,  C07C209/68

Abstract: HOE 91/F 225 Process for the production of pure 3,3',4,4'-tetraamino-biphenyl The present invention relates to a process for the preparation of pure 3,3',4,4'-tetraaminobiphenyl in high yield by ammonolysis of 3,3'-dichlorobenzidine in the presence of copper powder and CuCl. After the crude product has been washed with ammonia water and water, the 3,3',4,4'-tetraaminobiphenyl, thus pretreated, is crystallized in water in the presence of 0 to 5 % by weight of activated carbon and of about 1 to 2 % by weight of a water-soluble reducing agent at temperatures of about 100 to about 140.degree.C, under a protective gas atmosphere (redissolution). The water-soluble reducing agent is an alkali metal dithionite or alkali metal sulfite. The protective gas used can be nitrogen. The water used in the recrystallization (redissolution water) can be reused in whole or in part in the recrystallization.

公开(公告)号：CA1292996C

公开(公告)日：1991-12-10

申请号：CA553206

申请日：1987-12-01

Applicant: HOECHST AG

Inventor： VORWERK EDGAR

IPC: C07C51/29 ,  C07C63/70

Abstract: of the disclosure: The invention relates to a process for the preparation of 4-(2'-chloroethyl)benzoic acid or an aqueous solution of its sodium and/or potassium salt from 4-(2'-chloroethyl)-acetophenone. In this process, 4-(2'-chloroethyl)-acetophenone is reacted with an aqueous alkaline solution of sodium hy-pochlorite and/or potassium hypochlorite at temperatures between 25.degree.C and 110.degree.C. The free acid can be pre-cipitated by acidification using a strong inorganic acid from the thus obtained aqueous solution of the sodium and/or potassium salt of the 4-(2'-chloroethyl)benzoic acid.

公开(公告)号：CA2008557A1

公开(公告)日：1990-07-26

申请号：CA2008557

申请日：1990-01-25

Applicant: HOECHST AG

Inventor： PAPENFUHS THEODOR ,  HESS REINER ,  VORWERK EDGAR

IPC: C07B61/00 ,  C07C209/10 ,  C07C211/52 ,  C07C211/59

Abstract: HOE 89/F 026 Process for the preparation of 2-nitro-4-trifluoromethyl-aniline A process for the preparation of 2-nitro-4-trifluoro-methylaniline, wherein excess aqueous ammonia is allowed to act on 4-chloro-3-nitrobenzotrifluoride at temperatures of about 80 to about 150.degree.C, if appropriate in the presence of a copper catalyst.