Abstract:
In order to improve the catalytic performance of catalysts on glycerol dehydration,the active components were selected and the support was modified in the present study.The influence of reaction conditions on the conversion rate of glycerol and the selectivity rate of acrolein was also studied.The catalysts were prepared by the initial wetness impregnation method,with γ-Al
2O
3as support,and H
3PO
4,H
4SiW
12O
40,H
3PW
12O
40and H
3PMo
12O
40as the active components.The catalytic performance of the prepared catalysts on the gas phase dehydration of glycerol to acrolein under atmospheric pressure was examined.The results showed that γ-Al
2O
3supported H
4SiW
12O
40had excellent catalytic performance on the dehydration of glycerol to acrolein.The conversion rate of glycerol and the selectivity rate of acrolein were 89.19% and 83.61% at 310℃,respectively,when 20% glycerol aqueous solution was fed at a rate of 0.1 mL/min.The
γ-Al
2O
3modified by B
2O
3or ZrO
2could improve the catalytic performance of
γ-Al
2O
3supported H
4SiW
12O
40catalyst.The conversion rate of glycerol was reached to 100% and the selectivity rate of acrolein was up to 85.32% at 310℃ with B
2O
3modified
γ-Al
2O
3supported H
4SiW
12O
40as catalyst.Furthermore,the effect of the load amount of H
4SiW
12O
40,the concentration of glycerol aqueous solution and liquid hourly space velocity on the catalytic performance of prepared catalysts was also investigated.The optimal conditions were as follows:the concentration of glycerol aqueous solution 35%,20% HSiW10% B
2O
3/
γ-Al
2O
3as catalyst and the liquid hourly space velocity 2.0 h
-1,under which the glycerol in feed was almost completely converting to products and the selectivity rate of acrolein was higher than 90%.