K~+/CaO催化糠醛与甲基异丁基酮缩合制备生物航空燃料中间体

将K_2CO_3溶于去离子水后,室温下负载到活化后的CaO上,采用"等体积浸渍-焙烧法"制备了负载型固体碱催化剂K~+/CaO,并用XRD和CO_2程序升温脱附(CO_2-TPD)对催化剂进行表征。研究了无溶剂条件下K~+/CaO催化糠醛与甲基异丁基酮缩合制备生物航空燃料中间体——亚糠基甲基异丁基酮(F-MIBK)的反应,考察了催化剂种类、K~+/CaO负载量、反应温度、反应时间及物料比等因素对目标产物收率和选择性的影响。结果表明:糠醛与甲基异丁基酮的缩合反应是在催化剂的强碱性位上进行的,K~+的加入明显提高了CaO的碱性,K_2CO_3负载量为1%时,催化剂K~+/CaO表现出了最优的催化性能;当甲基异丁基酮与糠醛的物质的量比值为2,催化剂用量为物料质量的10%,温度140℃,反应时间3 h时,糠醛的转化率为99.1%,F-MIBK的选择性和收率分别为98.2%,97.1%。

Production of Bio-aviation Fuel Intermediates by Aldol Condensation of Furfural and Methyl Isobutyl Ketone over K+/CaO

The supported solid base catalyst K+/CaO was synthesized by isometric impregnation-calcination method. The structure of catalysts were characterized by XRD and CO2-TPD. Preparation of the bio-aviation fuel intermediate of furfural-methyl isobutyl ketone ( F-MIBK) catalyzed by K+/CaO through condensation of furfural and methyl isobutyl ketone under solvent-free conditions was studied. The effects of different types of catalyst, different loading of alkali metal ion,reaction temperature, reaction time and the molar ratio of material on the reaction were investigated. The results indicated that the condensation reaction of furfural and methyl isobutyl ketone was carried on the strong basic sites of the catalyst, and the addition of K+ significantly improved the alkaline of CaO. K+/CaO gave the optimum catalytic performance with 1% loading of K2CO3 . When the molar ratio of furfural and methyl isobutyl ketone was 1∶2 and the amount of catalyst was 10% of the mass of the material at 140 ℃ for 3h, furfural conversion rate reached 99. 1%. The selectivity and yield of F-MIBK reached 98. 2% and 97. 1% ,respectively.