Study On Preparation Of Biodiesel From Different Oils Catalyzed By L-aspartic Acid Ionic Liquid

Biodiesel is a renewable energy source because its raw materials are animal and vegetable oils,microalgae and drainage oil.Biodiesel has excellent characteristics such as degradability,greenness and environmental protection.Therefore,biodiesel can be used as petrochemical diesel One of the ideal alternatives.The bottleneck in the production of biodiesel is mainly due to the high production cost and the environmental protection problems caused by the production process,which has great limitations on the large-scale production and application of biodiesel.Ionic liquids have become a preferred green catalyst for reducing production costs and environmental pollution in the process of biodiesel production.Their rational application can effectively promote the sustainable development of biodiesel.At present,the research of catalysis of imidazole and pyridine conventional ionic liquids is most extensive.The materials required for these ionic liquids are usually expensive,and most of them are difficult to reduce prices.They also cause environmental pollution and are difficult to degrade during the preparation process.In this paper,aiming at the defects and deficiencies of the catalysts selected in the field of biodiesel,combined with the previous research content of this research group,L-aspartic acid,which is relatively low in price and biodegradable,the synthetic amino acid ionic liquid was selected and evaluated based on the effect of catalyzing oleic acid,of which the ionic liquid[Asp]HSO₄ had the best catalytic effect.Subsequently,using ionic liquid[Asp]HSO₄ as a catalyst,a single factor study on the preparation of biodiesel catalyzed by different oils and fats was carried out,and the response surface optimization of the preparation of methyl oleate catalyzed by this ionic liquid was further studied,and the best process was determined.parameter.The specific conclusions are as follows:?1?A series of L-aspartic acid ionic liquids were prepared,and the same fatty acid was selected to screen the catalytic effect of ionic liquids.According to the results of preparation and tests,the prepared ionic liquids[Asp]HSO₄ was finally selected for subsequent experimental research.?2?First,a single factor experiment was carried out on the ionic liquid[Asp]HSO₄ catalyst.Select fatty acids such as oleic acid,stearic acid and lauric acid as raw materials,and use the homemade ionic liquid[Asp]HSO₄ as a catalyst to produce the corresponding fatty acid methyl ester by esterification reaction with methanol.By measuring the esterification rate,we search for the best Process parameters.The use of edible grade soybean oil as the raw material to verify its catalytic transesterification effect.Through experiments,the best conditions for ionic liquid[Asp]HSO₄ catalyzed oleate esterification reaction are:alkyd ratio?molar ratio of methanol to fatty acid?7:1,aspartic acid ionic liquid dosage is 20%The mass of aspartic acid ionic liquid and the mass of fatty acids participating in the reaction),the temperature is 85±2?,the reaction time is 24 h,and the esterification rate of fatty acids under this condition is 97.7%;The reaction conditions are:alkyd acid ratio 5:1,aspartic acid ionic liquid dosage 10%,temperature 55±2?,reaction time 15 h,under this condition the esterification rate of fatty acid is 93.16%;catalytic laurel The optimal reaction conditions for the esterification reaction are:the ratio of alkyd acid 3:1,the amount of aspartic acid ionic liquid is 5%,the temperature is 65±2?,the reaction time is 33 h,under these conditions the fatty acid esterification The rate is91.09%.The optimal reaction conditions for catalyzing the transesterification of soybean oil are:the amount of ionic liquid catalyst accounts for 5%of the mass of soybean oil,the temperature is 85±2?,the reaction time is 9 h,and the ratio of the amount of methanol to soybean oil is 5:1 Under this condition,The yield of the product under this condition can reach 40.57%,indicating that this ionic liquid is not suitable for catalyzing transesterification.?3?On the basis of single-factor experiment,oleic acid was selected as the raw material,and the self-made ionic liquid[Asp]HSO₄ was used as the catalyst to carry out response surface optimization test research,and the best process of esterification reaction between oleic acid and methanol was obtained through the experiment Conditions,that is,the reaction temperature is 81?,the reaction time is 25 h,the amount of catalyst is 21%of the mass of oleic acid,the ratio of the amount of methanol and oleic acid is 7:1,and the esterification rate is measured under this condition 97.16%,the error from the predicted value is less than 5%,indicating that the test results are reliable.?4?According to the optimization results of the single-factor experiment of each raw material,the experiment of reusing the ionic liquid separately.The experimental results show that ionic liquid is easy to separate and recycle,and can be reused multiple times.A cost-effective catalyst.