改性SBA-15固载磷钨钼多酸H3PWnMo12-n-O34(n=0,6,12)催化合成柠檬酸三丁酯

Catalytic synthesis of tributyl citrate with modified SBA-15 supported phospho-tungsten-molybdenum polyacid H3PWnMo12-n-O34(n=0,6,12)

以3-氨丙基三乙氧基硅烷改性的SBA-15为载体,以具有不同组成的Keggin型磷钨钼杂多酸H3PWnMo12-n-O34(n=0,6,12)为固体酸催化剂,通过对SBA-15表面修饰获得一系列介孔分子筛/硅烷偶联剂@磷钨钼杂多酸复合催化剂PWMo@SBA-15/Apts,并利用FTIR、P-XRD、TEM、N2吸附-脱附对复合催化剂的组成、结构及形貌进行了表征.以PWMo@SBA-15/Apts为催化剂对柠檬酸三丁酯的催化合成进行研究,考察不同多酸组成、催化剂用量、酸醇物质的量比、反应时间、反应温度对催化合成柠檬酸三丁酯酯化率的影响.结果表明:固载磷钨酸催化剂合成柠檬酸三丁酯的酯化率最高可达97.36%,重复使用8次后酯化率仍可达74.38%.

A series of mesoporous molecular sieves/silane coupling agent@phosphotungstic-molybdium acid composite catalysts PWMo@SBA-15/Apts were prepared through surface modification of SBA-15,when the 3-aminopropyltriethoxysilane modified SBA-15 was used as carrier and the Keggin type phosphotungsticmolybdium acid with different composition H3PWnMo12-n-O34(n=0,6,12)were used as solid acid catalysts.The composition,structure and morphology of the composite catalysts were characterized by FTIR,P-XRD,TEM and N2 adsorption-desorption.The catalytic synthesis of tributyl citrate was studied with PWMo@SBA-15/Apts as catalysts.The effects of composition of polyacid,amount of catalyst,molar ratio of acid to alcohol,reaction time and reaction temperature on the esterification rate of tributyl citrate were studied.The results showed that the highest esterification rate of tributyl citrate was 97.36%catalyzed by supported phosphotungstic acid catalyst,and the esterification rate was still 74.38%after 8 times of recycling.