Abstract: Improved methods and apparatus for the preparation of maleic anhydride by reacting a hydrocarbon having at least four carbon atoms in a straight chain with molecular oxygen in a catalytic reactor, the reactor comprising a fixed catalyst bed having active sites comprising a vanadium-phosphorus-oxygen catalyst for the catalytic oxidation of the hydrocarbon to maleic anhydride, said process further comprising the continuous or intermittent introduction of a phosphorus-containing agent to the reactor. The introduction of the phosphorus-containing agent into the maleic anhydride production system is controlled so to provide for a more uniform distribution of the phosphorus-containing agent throughout the reactor. The methods of the invention are effective to reduce deposits of the phosphorus-containing agent or decomposition products of the phosphorus-containing agent on reactor surfaces other than the catalytic bed thereby decreasing reactor maintenance and increasing reactor lifetime.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

Abstract: An improvement in the process of electrohydrodimerizing acrylonitrile to adiponitrile wherein metal-plated cathodes, which are employed in the process as a part of an electrolytic cell, are pretreated by wetting the cathodes with aqueous phosphoric acid thereby to significantly reduce fouling.

Abstract: In a process for hydrodimerizing an olefinic nitrile, amide or ester by electrolyzing an aqueous solution of the olefinic starting material, conductive salt and a nitrilocarboxylic acid compound that inhibits formation of hydrogen at the cathode, such hydrogen formation can be even further inhibited and the current efficiency of the process significantly further increased by including in the solution a tri(C.sub.2 -C.sub.4 alkanol)amine such as triethanolamine.