Maleic anhydride prepn - using a catalyst contg u,v,p and o

摘要

Maleic anhydride is prepd. by gas phase oxidn. of benzene, aliphatic hydrocarbons with 4-5 C and 1- or 2 olefinic double bonds (which are linear when contg. 4 C) or monoethylenically unsatd. aldehydes with 4 or 5 C in which the olefinic double bond is beta to the carbonyl gp., oxidn. being effected in presence of a catalyst comprising a cpd. of V, U, P and O, and wherein the molar ratio U:P = 0.2:1 to 2:1, P:O = 0.1:1 to 0.35:1, and the atomic ratio V:U = 0.1:1 to 2:1. Claimed process ensures high yield. Benzene, butene-2, pentenal-2 are suitable starting materials. Catalyst may be prepd. from UO2(NO3)2.6H2O vanadyloxalate, and H3PO4.