Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1992-08-20
1994-11-22
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
562457, C07C22900
Patent
active
053670965
ABSTRACT:
Process for the preparation of 2,5-di(phenylamino)terephthalic acid and dialkyl esters thereof in high purity.
The invention relates to a process for the preparation of dialkyl 2,5-di(phenylamino)terephthalates of the formula (I) ##STR1## in which R is a hydrogen atom or a methyl group and R' is a methyl group or ethyl group, by dehydrogenation (oxidation) of the corresponding dialkyl 2,5-di(phenylamino)-3,6-dihydroterephthalate with oxygen, which comprises blanketing with oxygen a solution or suspension of the dialkyl 2,5-di(phenylamino)-3,6-dihydroterephthalate in aromatic hydrocarbons in a stirred vessel, circulating this reaction mixture via a spraying device, so that the sprayed reaction mixture is distributed over the reaction mixture present in the stirred vessel, the sprayed reaction mixture being mixed with the circulating gas.
The process has the advantage of a short reaction time, combined with favorable space-time yields and simplicity in terms of apparatus.
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patent: 3555087 (1971-01-01), Grosso et al.
patent: 3671451 (1972-06-01), Butterfield
patent: 4432940 (1984-02-01), Buyalos
patent: 4981997 (1991-01-01), Schutze et al.
patent: 5208365 (1993-05-01), Fuchs et al.
Chemical Engineers' Handbook, 1973 Robert H. Perry/Cecil H. Chilton pp. 18-58-18-67.
Ritter Eberhard
Schafer Hans
Schottler Martin
Vollheim Thomas
Barts Samuel
Dees Jos,e G.
Hoechst Aktiengesellschaft
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