Comparative Research On Biodiesel Production By Ionic Liquid As Catalyst

Object:Comparative research on transesterification of cottonseed oil used ionic liquids ([BmimJOH, [Emim]OH), NaOH and Nov435 as catalysts. The effect of the molar ratio of methanol to oil, amount of the catalyst, reaction time and temperature on transesterification by the yield of biodiesel were obtained, and the optimum conditions was acknowledged by [Bmim]OH as catalysts through orthogonal analysis.Methods:Prepared cottonseed oil biodiesel by ionic liquids ([Bmim]OH, [Emim]OH), NaOH and Nov435 as catalysts. Qualitative and quantitative analysis of biodiesel were followed by HPLC chromatography and Thin-layer chromatography. And the single-factor's effect and the optimized reaction conditions were obtained through multi-level and single-factor experiments and orthogonal experiments. The yield of biodiesel, the stability, the repeatedly use and cost by different catalysts was comparatively analyzed.Results:1. Produced cottonseed oil biodiesel by [Bmim]OH as catalyst. Determined the four important factors by the orthogonal experiments, and the results are as follows:molar ratio of methanol to oil>amount of the catalyst>time of reaction>temperature of reaction and the optimum condition is that molar ratio of methanol to oil is 7:1, amount of catalyst is 3.5%, time of reaction is 50min and temperature of reaction is 55℃, the yield of biodiesel from 91.7% to 93.5%; and the catalyst is steady and can be used repeatedly more than 6 times.2. Produced cottonseed oil biodiesel by [Emim]OH as catalyst. Determined the four important factors by the orthogonal experiments, and the results are as follows:molar ratio of methanol to oil>temperature of reaction>time of reaction> amount of the catalyst and the optimum condition is that molar ratio of methanol to oil is 6:1, amount of catalyst is 3.5%, time of reaction is 50min and temperature of reaction is 55℃, the yield of biodiesel from 89.8% to 90.7%; and the catalyst is steady and can be used repeatedly more than 6 times.3. Produced cottonseed oil biodiesel by NaOH as catalyst. Determined the four important factors by the orthogonal experiments, and the results are as follows:molar ratio of methanol to oil>time of reaction >amount of the catalyst>temperature of reaction and the optimum condition is that molar ratio of methanol to oil is 7:1, amount of catalyst is 1.4%, time of reaction is 60min and temperature of reaction is 55℃, the yield of biodiesel from 89.7% to 90.9%.4. Produced cottonseed oil biodiesel by Nov435 as catalyst. Obtained the reaction conditions which are the molar ratio of methanol to oil is 3.5:1, amount of catalyst is 10%, time of reaction is 24h, temperature of reaction is 50℃and the stirring speed is 160r/min. Yield of biodiesel is all above 90%, and the catalyst can be used repeatedly after processed by organic solvents.Conclusion:1. Prepared cottonseed oil biodiesel by ionic liquids, NaOH and Nov435 as catalysts. Qualitative and quantitative analysis of biodiesel were followed by HPLC chromatography and Thin-layer chromatography.2. Weighed the importance of different factors which are the molar ratio of methanol to oil, amount of the catalyst, time of reaction and temperature of reaction, and obtained the optimized reaction conditions through multi-level and single-factor experiments and orthogonal experiments.3. Compared the yield of biodiesel under the optimum conditions, and analyzed the cost, the time of the repeatedly use and the environmental effect of the four catalysts, and [Bmim]OH was acknowledged as the superior catalyst, and it will be widely used in the future.