Ammoxidation and oxidation of substituted methyl aromatics on vanadium-containing catalysts

An overview of the state of the art and future trends in vapour phase oxida tion and ammoxidation of substituted methyl aromatics and heteroaromatics i s presented. The topics mainly contain the conversion of methoxytoluenes, c hlorotoluenes and methylpyridines to the corresponding aldehydes and nitril es by vapour phase reaction using V-containing catalysts. Steric and electr onic effects of various substituents in combination with acid-base properti es of catalyst surfaces on the catalytic performance are discussed; common features and differences in mechanistic steps are demonstrated. The optimum catalyst composition for vapour phase partial oxidation to aldehydes is qu ite different from that for vapour phase partial ammoxidation to nitriles. (C) 2000 Elsevier Science B.V. All rights reserved.