Dicational Ionic Liquid For The Biodiesel Preparation From Waste Cooking Oil

With the global energy shortage and the environmental awareness of human, looking for the renewable energy is urgently needed. Biodiesel is concerned as a renewable and clean energy. Biodiesel, namely fatty acid methyl ester could be obtained by the esterification and transesterification. However, the catalyst is a key factor to the transesterification, the traditional acid/base catalysts are simple and cheap, but they are the disadvantages of corroding equipment, separating products difficultly and disposing the next work complexly and so on. The ionic liquid is a new kind of environmentally friendly solvent and catalyst that could produce the biodiesel efficiently and environmentally friendly. This is under the support of the National Natural Science Foundation(51306081), and the several new double ionic liquid were catalyzed the preparation of biodiesel. The main contents are as follows:(1)Waste cooking oils were examined to the physical and chemical properties. The results showed that the physical and chemical properties of them were similar with the natural oils and fats, except the water content and acid value.(2)Basic dicationic ionic liquid(C6(mim)2-OH) was synthesized by two-step methods. By using glycerol trioleate as the model, the influence on the model reaction and reusability of catalyst were investigated. The optimal condition is that mole ratio of oleyl and alcohol is 1:9, the amount of catalyst is 5wt %, reaction temperature is 120 ?, and reaction time is 5 h. The yield of product can reached up to 96.2% under this optimum condition. Moreover, the catalyst can be reused for 7 times with a slight decreasing of activity. The yield of biodiesel from wasted cooking oil is up to 93.6% under same condition.(3)The sulfonate dication ILs with different chain length were synthesized through the two step method under the ultrasonication condition, and the catalytic activity of them was examined. the yield of biodiesel from the transesterification of glycerol trioleate with methanol can reach up to 95.3% under the optimal condition, waste cooking oil could high effective convert into biodiesel(93.9%) under the same condition. the catalysts could be recycled 6 times with a little loss every recycle in catalytic activity and the yield of biodiesel still retained 81%.(4)The acidic sulfate dication ionic liquid C3 MS was prepared and then was used as the catalyst in the transesterification of soybean oil and waste cooking oil in subcritical methanol. The results showed that the catalyst exhibited excellent high stable and high catalytic activity. The yield of biodiesel from soybean oil under optimum conditions was up to 98% and it could be maintained at 93.7% after it had been reused for 7 times. Under the same condition, the yields of biodiesel from four kinds of waste cooking oil with high free acid and water content were more than 92%, and the highest yield could reach up to 97.2%.(5)The double cation ionic liquid was synthesized, and the effects of the reaction conditions on the yield of biodiesel by the transesterification of waste cooking oil were analyzed. Under the conditions of the catalyst dosage(mass ratio) 10%, the molar ratio of oil and alcohol for 1:15 and the reaction time 2h, the yield of biodiesel was 98.5%. The catalyst could be recycled. Moreover, the properties of the biodiesel from the waste cooking oil accord with the GB of biodiesel and become better compare with the common diesel.