Study On Triptane Preparation Process Using Methanol As Raw Material

With the rapid development of China's general aviation industry,the demand for aviation gasoline will increase rapicdly.At the same time,in order to meet stringent environmental requirements,unleaded aviation gasoline will be the general trend.2,2,3-trimethylbutane(triptane)has high octane number and excellent blending properties,so triptane is an ideal component for the production of high-octane unleaded aviation gasoline.Triptane can be prepared by using methanol as raw material.In this paper,the batch preparation conditions of triptane with methanol as feed and zinc iodide as catalyst were studied.The mixture of hydrocarbons with a triptane content of 27.3%was obtained at 200? and a molar ratio of methanol to zinc iodide is 2:1.Under this condition,the effect of cyclic reaction on the stability of the catalyst was investigated.The experiment results show that as the number of cyclic reactions increases,the degree of oxidation of the catalyst increases,and the iodine element in zinc iodide is obviously lost.The addition of methyl iodide in the cyclic reaction can effectively increase the oil yield and triptane yield,and supplement the iodine element lost by the catalyst,but the reaction results is still weaker than the reaction using fresh zinc iodide catalyst.Further research using the continuous experimental equipment for preparing triptane showed that the catalytic activity was not significantly attenuated after 14 h of stable reaction.Low ering the temperature of the top of the reactor could increase the oil yield,but if the reaction pressure was too high,the catalyst was completely dissolved and the reaction could not be carried out.The optimum process conditions of the equipment were:reaction zone temperature of 200?;top temperature of 170?;zinc iodide catalyst loading of 15 g;system pressure of 1 MPa;methanol feed rate of 5 ml/h.The oil product mass yield is 10.2%,and the triptane carbon molar yield can reach 8.8%.In the batch process and the continuous process,the propanol-methanol,butanol-methanol,i-pentanol-methanol mixed feedstocks are respectively reacted,and the results show that in the batch reaction,the triptane carbon molar yield obtained by i-propanol-methanol mixed feedstock(12.5%)is higher in several mixed feedstocks,which up to 13.2%.In the continuous reaction,compared with the reaction result of the mixed feedstock of 7.5%,the triptane carbon molar yield of the n-butanol-methanol mixed feed is higher,which up to 10.8%.Combine the results of batch process and continuous process,the i-pentanol-methanol mixed feedstock has an obvious improvement on the oil yield;if the proportion of methanol in the mixed feedstock decrease,the selectivity of triptane xwill also be significantly reduced;in the continuous process and the batch process,the mode of feeding and discharging are different,and the reaction results are also different,and the boiling point of the feedstock has a great influence on the reaction result of the continuous process.