Montedison S.p.a.

Giancarlo Battiston

Mario Padovan

Romano Covini

Guido Petrini

Giordano De Alberti

Giordano DeAlberti

Giuseppe Leofanti

Francesco Pignataro

A process is disclosed for the preparation of acrylic acid or methacrylic acid by reacting in vapor phase acrolein or methacrolein with molecular oxygen or with an oxygen-containing gas, at a temperature between 200.degree. and 350.degree. C., in the presence of a solid catalyst and with a contact time between 0.5 and 5 seconds, characterized in that said catalyst consists of molybdenum, vanadium, tungsten, one or more of the elements selected from the class consisting of silver, titanium, chromium, cerium, lanthanum and tantalum, and oyxgen chemically combined with the above-indicated elements, and wherein the atomic ratios between the various elements present in the catalyst are represented by the empirical formula:

Process for the preparation of unsaturated carboxylic acids by the

A process is disclosed for preparing unsaturated carboxylic acids consisting essentially in reacting in the vapor phase an unsaturated aldehyde with molecular oxygen or an oxygen-containing gas, at a temperature ranging from 200.degree. to 370.degree. C., in the presence of a solid catalyst, with a contact time between 0.5 and 5 seconds, characterized in that the catalyst consists essentially of molybdenum, vanadium, cobalt, and optionally tungsten, these elements being chemically combined with oxygen and the atomic ratios of the elements being represented by the empirical formula Mo.sub.12 V.sub.a W.sub.b Co.sub.c O.sub.d

Process for preparing unsaturated carboxylic acids by the catalytic

A process is disclosed for preparing acrylic acid or methacrylic acid comprising reacting in vapor phase acrolein or methacrolein (respectively) with molecular oxygen or an oxygen-containing gas, at a temperature between 200.degree. and 350.degree. C, in the presence of a solid catalyst, and with a contact time between 0.5 and 5 seconds, characterized in that the solid catalyst comprises molybdenum, vanadium, tungsten, cobalt, chromium and oxgyen chemically combined with these elements, the atomic ratios among the aforesaid elements being represented by the empirical formula: Mo.sub.12 V.sub.a W.sub.b Co.sub.c Cr.sub.d O.sub.e, wherein:

Process for preparing unsaturated carboxylic acids by gas phase

A process is disclosed for the preparation of acrylic acid or methacrylic acid, comprising reacting in vapor phase acrolein or methacrolein with molecular oxygen or an oxygen-containing gas, at a temperature between 200.degree. and 350.degree.C, in the presence of a solid catalyst, and with a contact time between 0.5 and 5 seconds, wherein the catalyst consists of molybdenum, vanadium, tin, and one of the elements chromium, nickel, manganese, as well as oxygen chemically combined with the above-indicated elements, the atomic ratios of the elements being represented by the empirical formula:

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Baranzate, Italy

Giancarlo Battiston