介孔分子筛P-SBA-1催化合成柠檬酸三丁酯

Synthesis of tri-butyl citrate over mesoporous molecular sieve P-SBA-1 catalyst

采用后合成法制备了介孔分子筛催化剂P-SBA-1,并用XRD和SEM对催化剂进行分析,表征结果表明催化剂P-SBA-1具有立方结构(空间点群Pm3n)。选用液体酸H2SO4和微孔分子筛HY、ZSM-5与SBA-1进行对比,结果表明催化剂的活性高低顺序为:H2SO4>SBA-1>HY>ZSM-5。将改性后的介孔分子筛P-SBA-1作为固体酸催化剂合成柠檬酸三丁酯。重点考察了催化剂用量、酸醇摩尔比、反应温度、反应时间等因素以及催化剂的重复使用性能。结果表明P-SBA-1催化合成柠檬酸三丁酯的最佳条件为:反应温度140℃,酸醇摩尔比1∶6,催化剂用量为反应物总质量的1.5%,反应时间5h。催化剂P-SBA-1重复使用性能良好。

The mesoporous molecular sieve P-SBA-1 functionalized with phosphoric acid group was prepared by post-synthetic method.The samples were characterized with XRD and SEM.The results confirmed that P-SBA-1 catalyst remains the well ordered cubic structure（space group Pm3n）.The catalytic activity of SBA-1,as compared with H2SO4,HY、ZSM-5,was tested on the esterification reaction of citric acid.From the results,it was clear that the activity of the catalysts for esterification of citric acid was found to follow the sequence： H2SO4SBA-1HYZSM-5.The tri-butyl citrate was prepared using P-SBA-1 as solid acid catalyst.The effects of amount of catalyst,acid/alcohol molar ratio,reaction temperature and reaction time were investigated.The optimum conditions for the synthesis of TBC over P-SBA-1 were： reaction temperature was 140℃;the ratio of citric acid to butanol was 1∶6;mass ratio of catalyst to reactant was 1.5﹪ and reaction time was 5h.The catalyst was highly stable and can be used for several times without much loss of its activity.