Robert E Mccall

US Patent:

39819353, Sep 21, 1976

Filed:

Dec 10, 1975

Appl. No.:

5/639875

Inventors:

Robert McCall - Newark DE

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

C07C 7910

US Classification:

260645

Abstract:

A duplex process for the mononitration of benzene wherein the nitration is carried out in an azeotropic first stage followed by a lower temperature, mixed-acid second stage. The azeotropic stage uses reaction temperatures of at least 120. degree. C in mixed HNO. sub. 3 --H. sub. 2 SO. sub. 4, and excess water is carried overhead as an azeotrope with part of the benzene and is then decanted from the benzene. The nitrated benzene is removed as bottoms and decanted from the acid phase, avoiding the necessity of reconcentrating the H. sub. 2 SO. sub. 4. Both the nitrated benzene bottoms and the organic, benzene-containing part of the overhead stream are supplied to the second stage for completing the conversion into mononitrobenzene in mixed acid at lower temperatures such as 70. degree. C.

US Patent:

43318193, May 25, 1982

Filed:

Apr 24, 1980

Appl. No.:

6/143372

Inventors:

Robert McCall - Newark DE

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

C07C 7602
C07C 7910

US Classification:

568939

Abstract:

The invention relates to a process for the preparation of nitrated aromatic compounds by the mixed acid process, in which water is removed from the reaction mass by passing an inert gas through it.