systems could favor the localization of tellurium either by means of interstitial or substitutional solid solution.The nature of the active sites in oxidative dehydrogenation of 1-butene to butadiene has also been discussed in terms of possible formation of Te==O groups or modification of M-0 groups previously present or even formation of Te==O M e 0 gem groups.
AcknowledgmentsWe thank Professor I. Pasquon for encouragement and useful discussion and Italian Consiglio Nazionale delle Ricerche (Rome) for financial support.
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(1975).Received for reuieui M a r c h 16, 1976 Accepted November 14, 1976 The catalytic oxidation of H2S with O2 at 200 OC on various porous materials was investigated. The influence of the pore structure and the chemical composition of the materials on the activity and the selectivity toward the product (sulfur) was studied. It was found that in materials with an average pore diameter between 5 and 10 A the sulfur adsorption is strong. The catalytic activity per square meter of total surface area is approximately proportional to the amount of adsorbed sulfur. In this case the selectivity towardwdfur is high. In materials with larger pores sulfur adsorption is enhanced by the presence of Lewis acid sites and by a hydrophobic surface. For these materials the presence of water in the feed has an activity lowering effect. If iron oxide is present, at 200 OC, SO2 is the main product. This is the case when other group 6-8 metal ions are present. For practical use in an H2S removal process the industrial active charcoals, zeolite NaX, Ti02, and ZrOp are most suitable.
