The Vapor Phase Oxidation of 1, 3-Pentadiene

The vapor phase oxidation of 1.3-pentadiene, over heterogeneous catalysts, was investigated with the objective of producing 2,4-pentadienal and 2,4-pentadienoic acid. Copper and cobalt-molybdenum catalysts, both supported and unsupported, were utilized at various reaction temperatures, residence times and feed ratios. The matter of 1,3-pentadiene vaporization and introduction into the reactor system proved to be critical. Low temperature vaporization of the hydrocarbon and dilution with the oxidant, air, was found to be necessary to avoid polymerization of the feed. Alumina-supported catalysts were found to be very active, leading to severe cracking of the hydrocarbon feed and subsequent carbonization of the catalysts. Silica-supported catalysts did not suffer from this problem. At all conditional studied the oxidations were non-selective, with numerous products being observed. The desired product, 2,4-pentadienoic acid, was observed only in trace amounts over cobalt molybdate. 2,4-Pentadienal was observed over all catalysts. The highest yield of 2,4-pentadienal, 11%, occurred over cobalt molybdate