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:
Jul. 06, 1993
Filed:
Apr. 09, 1991
Applicant:
Inventors:
Heinrich Aichinger, Mannheim, DE;
Wilhelm Ruppel, Schwetzingen, DE;
Rolf Seubert, Frankenthal, DE;
Karl-Heinz Boehning, Ludwigshafen, DE;
Walter Scheidmeir, Limburgerhof, DE;
Johannes E Schmidt, Ludwigshafen, DE;
Matthias Schwarzmann, Limburgerhof, DE;
Assignee:
BASF Aktiengesellschaft, Ludwigshafen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
549248 ; 549247 ; 549257 ; 549259 ; 549260 ;
Abstract
Phthalic anhydride is prepared in a multiple tube reactor provided with separate salt baths, the temperature of the salt bath used for cooling the first layer of catalyst, as regarded in the direction of flow of the reaction mixture, being from 2.degree. to 20.degree. C. higher than that of the salt bath(s) associated with the following layer(s).