Rohm Gmbh

Roehm Gmbh Chemische Fabrik

Hermann-Josef Siegert

Siegmund Besecke

Guenter Schroeder

Wolfgang Gaenzler

Wolfgang Ruppert

Wilhelm Gruber

Gunter Schroder

Ernst Bielmeier

Thomas Haeberle

The present invention relates to a process for the production of methacrylic acid and methacrolein by means of gas phase oxidation of isobutane in the gaseous phase at 250.degree. to 450.degree. C. on molybdenum heteropoly acid catalysts that are made up of CU.sub.a H.sub.b P.sub.c Mo.sub.d V.sub.e O.sub.f heteropoly acid compounds (I), where a=0.1 to 1, b=0 to 7.8, c=0.8 to 1.2, d=9 to 12, e=0.5 to 3, and f depends on the molar numbers a to e, and/or the heteropoly acid H.sub.8 PMo.sub.10 VO.sub.39 (II) or its anhydride PMo.sub.10 VO.sub.35 (III).

Process for producing methacrylic acid and methacrolein by oxidation of

In the manufacture of isobutyric acid or its precursors or esters by the Koch synthesis from propylene, carbon monoxide, and, optionally, water or an alcohol in liquid hydrogen fluoride, the reaction mixture is maintained at a constant reaction temperature in a heat exchanger using an addition product of at least two of the aforementioned materials, preferably isopropanol, as a coolant.

Method for making isobutyric acid

In the continuous preparation of isobutyric acid by the Koch synthesis from propylene, carbon monoxide, and water or an alcohol in hydrogen fluoride under pressure, the reaction mixture, after reaction, is depressurized, a principal amount of the gaseous components to be removed is separated, the remaining liquid phase is introduced into the middle to upper region of a distillation column in which base temperature is kept above the boiling point of isobutyric acid and the head temperature is kept near the boiling point of hydrogen fluoride, and isobutyric acid is removed as a liquid of high purity from a plate below the entrance of the feed.

What is disclosed is a continuous one-step method for the preparation of isobutyric acid or a lower alkyl ester thereof by the Koch synthesis, which method comprises reacting propylene, carbon monoxide, and water or a lower alcohol, in the gaseous and liquid phases, in the presence of hydrogen fluoride as a Koch catalyst, at a temperature between 80.degree. C. and 160.degree. C., at a dwell time of the liquid phase of less than 20 minutes, and with a high degree of backmixing, while maintaining the content of propylene in the reaction mixture at less than one percent by weight of the liquid phase, wherein all or part of the propylene, carbon monoxide, and water or lower alcohol can be replaced by binary addition compounds formed pairwise between these materials. In the alternative, isopropylformiate can be continuously rearranged in the presence of hydrogen fluoride to produce isobutyric acid.

What is disclosed is a process for the continuous production of isobutyric acid or an alkyl ester thereof by the Koch synthesis, which process comprises reacting propylene, carbon monoxide, and water or an alkanol in the presence of hydrogen fluoride in at least one reaction space containing a liquid phase and a gas phase under high pressure, releasing said pressure at least partially, whereby a gas containing organic compounds from said synthesis evolves from said liquid phase, adding oxygen to said evolved gas and at least partially combusting the organic compounds contained therein, then contacting the evolved gas containing the at least partially combusted organic compounds with at least a portion of the water or alkanol to be reacted with said propylene and carbon monoxide, whereby at least a portion of said combusted organic compounds are absorbed by said water or alkanol, returning said water or alkanol containing the absorbed combusted organic compounds to said reaction space, and discharging any unabsorbed gas from the reaction system.

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Seeheim-Jugenheim, Germany

Hermann-Josef Siegert