Dehydration of ethanol to diethyl ether over beta zeolite catalysts

Abstract

The catalytic ethanol dehydration to diethyl ether was investigated using synthesized beta zeolite catalysts having different Na and mixed Na-H form. The Na form in catalyst was synthesized by the hydrothermal process including non-calcined (Na-BEA_N) and calcined (Na-BEA_C) catalysts. The catalysts having different mixed Na-H forms were synthesized under ion-exchange method. In this study, two different cycles were chosen including one cycle (M-BEA_1) and four cycles (M-BEA_4). These catalysts were characterized by various techniques. The catalysts were tested to measure the catalytic activity at atmospheric pressure and the reaction temperature ranged from 150 to 400 °C. The results presented that the M-BEA_1 catalyst exhibited the highest DEE yield of 27.3% at 250 °C due to its large surface area and highest moderate acid site. In addition, the optimal condition was examined by various factors consisting WHSV, carrier gas (N2) flow rate and ethanol concentration. It was observed that the low WHSV, carrier gas and ethanol concentration gave the highest DEE yield of 66.4% at 200 °C. Furthermore, the M-BEA_1 catalyst was modified with yttrium (Y) or phosphorus (P). It was found that both modifications with Y or P had effect on physical properties and acidity, resulted in decreased surface area and moderate acid site. It can be concluded that the modification of Y or P on beta zeolite catalyst decreased the DEE yield.