A series of TiO2-ZrO2 mixed oxides with varying molar ratio of TiO2 to ZrO2 were prepared by the co-precipitation method. The crystalline phases of the oxides were characterized by XRD and their acid-base properties by TPD of NH3 and CO 2 and IR of adsorbed pyridine. The catalytic activities were investigated for the vapor phase dehydration of methanol to dimethyl ether (DME) in a fixed-bed reactor under atmospheric pressure. The mixed oxides are highly amorphous in nature. The acid-base properties and CH3OH conversion activity are increasing with TiO2 content and an optimum value is achieved for a molar ratio of Ti/Zr in the vicinity of 1/1. At lower reaction temperature (< 300°C), the selectivity for DME is nearly 100%. A good correlation is observed between dehydration activity and the acid-base properties of the TiO2-ZrO2 catalysts. It is significant to note that TiO2-ZrO2 catalysts show high stability against water during dehydration reaction. Based on our results, a surface mechanism involving both acid-base sites has been proposed for DME formation.
|Number of pages||6|
|Publication status||Published - 2004 Jul 1|
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