Ferdinand B. Zienty

Metal oxide activities in the oxidation of ethylene

Abstract The complete oxidation of ethylene over various supported metal oxides was studied as a means of assessing catalytic activities. The oxides of Co and Cr were most active. Comparison with other activity patterns shows that chromia is highly active whenever hydrogen in some form is present on the surface. When benzene is completely oxidized over chromia an inversion in activity is noted, suggesting a change in oxidation state.

A study of the catalytic oxidation of benzene to maleic anhydride

Rate data are presented for the catalytic oxidation of benzene to maleic anhydride, CO and CO2 on a vanadia-molybdena catalyst. The catalyst is well defined by physical and chemical analysis including X-ray diffraction studies, titration of vanadium, EPR examination, surface area, and pore volume. A first order rate law is obeyed over the first 75% of reaction for several temperatures in the range 319 ° to 377 °C. It is concluded that benzene is oxidized in two independent ways, one path leading to oxides of carbon and the other to maleic anhydride, which is further oxidized. First order rate constants and apparent activation energies are given for the three paths. A partial mechanism accounting for the results is suggested by the use of absolute rate theory. It is proposed that in the rate-limiting step benzene can add molecular oxygen either in a 1,2- or 1,4- fashion to yield activated complexes possessing considerable mobility.