Catalytic Performance Of Modified CaO For No-Giycerol Biodiesel Preparation

In this work, a new method for no-glycerol biodiesel production has been established using mixture resource of rapeseed oil, dimethy carbonate and methanol. According to the reaction results, the highest biodiesel yield, 92.3%, was obtained at the optimized reaction conditions: catalyst dosage of 15%(the weight of oil), rapeseed oil/dimethy carbonate/methanol molar ratio of 1:1:8, reaction time of 8 h, and reaction temperature of 65*C. In order to improve catalytic efficiency and humidity resistance of calcium oxide, commercial calcium oxide was modified chemically. Finally, modifier was selected according to the yield of the biodiesel.(1) A highly modified Ca O was prepared by bonding butyl silicontrichloride and octadecyltrichlorosilane chemically on surface of Ca O. From the results it was shown that high biodiesel yield, 95.4%, was obtained over the Ca O modified with 0.1% octadecyltrichlorosilane under the optimum conditions of reaction temperature 65 C, reaction time 6h, catalyst dosage 15%, rapeseed oil/dimethy carbonate/methanol molar ratio of 1:1:8. The catalytic efficiency was great enhanced over modified Ca O by shorten the reaction time from 8h to 6h to 95.4% yield of biodiesel.(2) Good resistance to moisture has been obtained over modified Ca O with acromatic modifier and the absorbent rate under saturated water vapor atmosphere is 60% lower than the unmodified Ca O. However no obviously enhance of biodiesel yield can be observed over the acromatic reagent modified Ca O.(3) Good water resistance and catalytic performance were obtained over modified Ca O with ester modifier. From the result it was found that the Ca O modified with 0.01% ethyl bromoacetate reached high biodiesel yield of 98.8% under the optimum conditions of reaction temperature 65?C, reaction time 6h, catalyst dosage 15%,rapeseed oil/dimethy carbonate/methanol molar ratio of 1:1:8. which is 7.4% higher than unmodified Ca O after 8h.(4) ]n order to improve the catalytic performance of Ca O-based catalyst for transesterification of rapeseed oil with dimethy carbonate and methanol, composite solid based on Ca O was prepared by impregnation method. The catalytic activity were greatly improved by using Ca O supported KOH and Ca O supported Na Cl as catalysts. High biodiesel yield, 94.8% and 97.1%, were obtained over KOH/Ca O at 2h and Na Cl/Ca O at 1h respectively under the conditions of reaction temperature 65℃, rapeseed oil/dimethy carbonate/methanol molar ratio of 1:1:8.