Shape Selective Zeolite Catalyst Research Articles

Applications of molecular graphics to zeolite catalysts

The use of molecular graphics procedures to simulate hydrocarbon processes in zeolites is described. Calculations of heats of adsorption, activation energies for diffusion, and the location of solute molecules are considered, and a methodology for simulating an isomerisation reaction in a shape-selective zeolite catalyst is discussed.

Photoinduced methanol conversion to hydrocarbons on supported MoO 3 catalysts

Photocatalysis by powdered semiconductors has received much attention from the standpoint of photochemistry of solid surfaces as well as the utilization of solar energy. It seems to be important to clarify the role of surface ions at positions of coordinative unsaturation in photoinduced surface reactions, especially in the primary processes and the excited states of the catalysts. In connection with these problems the authors have recently investigated the photoluminescence of metal oxides as well as making ESR measurements of the transient intermediate species together with analyses of the photoreaction products. In previous papers, the authors have reported that the charge transfer excited state, (Me/sup (n-1)+/-O/sup -/), plays a significant role in photoreactions on supported transition metal oxides; the O/sup -/ species with trapped holes as well as the Me/sup (n-1)+/ ions with trapped electrons are closely associated with the key species of the photoinduced surface reactions. In the present work similar studies have been extended to the photoinduced decomposition of methanol on supported MoO/sub 3/ catalysts. It has been found that the reaction leads to the formation of hydrocarbons similar to those obtained in the methanol conversion reaction on shape-selective zeolite catalysts such as ZSM-5. 14 references

Recovery of ethanol from fermentation broths by catalytic conversion to gasoline

The technical and economic feasibility of recovering ethanol from fermentation broths by catalytic conversion to gasoline was investigated. Reactions of diethyl ether, ethanol, and aqueous 95 wt % ethanol over a shape-selective zeolite catalyst were studied in terms of product distributions, and the effects of pressure, temperature, and space velocity were established. Higher pressure was found to decrease the amount of gaseous hydrocarbon produced, while increasing the space velocity had the opposite effect. An optimum temperature of 623 K was found to maximize the amount of liquid paraffins and aromatics with a corresponding minimum in gaseous hydrocarbons. No significant effect of the presence of water in the feed stream was observed. A preliminary analysis revealed that the proposed process could offer significant economic advantages over traditional processes o ethanol recovery.