The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1977
Filed:
Jul. 11, 1975
Heinz Engelbach, Limburgerhof, DT;
Richard Krabetz, Kirchheim, DT;
Gerd Duembgen, Dannstadt-Schauernheim, DT;
Carl-Heinz Willersinn, Ludwigshafen, DT;
Ulrich Lebert, Ludwigshafen, DT;
Fritz Thiessen, Ludwigshafen, DT;
BASF Aktiengesellschaft, Ludwigshafen (Rhine), DT;
Abstract
In the oxidation of propylene to acrylic acid in the gas phase in two spatially separate oxidation stages, a part of the off-gas, which has been freed from condensable products, is fed to the oxidation stages in addition to freshly charged propylene and air, under the following conditions: A. The recycled off-gas and air are in part fed to the first oxidation stage and in part to the second oxidation stage, B. The molar ratio of propylene : oxygen : residual gases fed to the first stage is 1 : 1.5-2.3 : 11-19, C. The molar ratio of the total propylene fed in, to the total oxygen fed in, in the form of air or off-gas, before and after the first stage, and to the total residual gases fed in is 1 : 1.9-2.5 : 13-25, with the proviso that D. The air and the recycled off-gas are divided between the two feed points in such a way that from 10 to 50% by volume of the total quantity of air and off-gas fed in are added after the first stage and E. The air and off-gas are admixed to the reaction gas mixture after the first stage, immediately after it leaves the catalyst zone, so that the mixture is rapidly cooled to a temperature of from 150.degree. to 320.degree. C.