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USE OF POLYPHOSPHORIC ACID AS A REACTION MEDIUM FOR THE PREPARATION OF UNSYMMETRICAL DIARYLAMINES FROM SUBSTITUTED PHENOLS AND PRIMARY AROMATIC AMINES

IP.com Disclosure Number: IPCOM000024904D
Original Publication Date: 1982-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 79K

Publishing Venue

Xerox Disclosure Journal

Abstract

A process for the preparation of unsymmetrical diarylamines such as methyl-diphenylamine by reacting aniline and a phenol in the presence of a catalyst and a dehydration agent such as polyphosphoric acid (nominal formula H P4OI3). Higher polymers of phosphoric acid can also be used, e.g., P5, P6, and the hke.

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KEROX DISCLOSURE JOURNAL

USE OF POLYPHOSPHORIC ACID AS A RE- ACTION MEDIUM FOR THE PREPARATION OF UNSYMMETRICAL DIARYLAMINES

MARY AROMATIC AMINES Trevor Martin
John Lennon
Paul Szabo
Dan Freeman

Proposed Classification
U.S. C1. 260/576 Int. Cl. C07c 87/28

FROM SUBSTITUTED PHENOLS AND PRI-

A process for the preparation of unsymmetrical diarylamines such as methyl- diphenylamine by reacting aniline and a phenol in the presence of a catalyst and a dehydration agent such as polyphosphoric acid (nominal formula H P4OI3). Higher polymers of phosphoric acid can also be used, e.g., P5, P6, and the hke.

In one example conducted at atmospheric pressure, 100 grams of aniline, 132 grams of m-cresol and 432 grams of polyphosphoric acid were stirred in a reactor at 265OC for seven hours. The product was diluted with water, neutralized and extracted with dichloromethane. The extracts were distilled under reduced pressure to yield 58.2 grams of 3-methyldiphenylamine7 2.1 grams of diphenylamine and 68 grams of aniline. Eighty grams of m-cresol was obtained by acidification of the aqueous extracts followed by solvent extraction. Recovery of unreacted aniline and m-cresol were therefore 95 percent and 81 percent, respectively.

Another reaction carried out under pressure involved stirring 59.5 grams aniline,
34.56 grams m-cresol and 82 grams of polyphosphoric acid heated to 3OO0C under 250 psi in a sealed stainless steel reactor for six hours. The product was poured into water, neut...