H3PW6Mo6O40／SiO2催化合成7-羟基4-甲基香豆素

Catalytic synthesis of 7-hydroxy-4-methylcoumarin with H_3PW_6Mo_6O_(40)/SiO_2

采用溶胶-凝胶法制备了二氧化硅负载磷钨钼杂多酸催化剂H3PW6Mo6O40/SiO2,该催化剂制备的适宜条件是:m(H3PW6Mo6O40)∶m(SiO2)=40%,煅烧温度150℃,活化时间3 h。以二氧化硅负载磷钨钼酸为催化剂,在无溶剂条件下由间苯二酚和乙酰乙酸乙酯为原料进行Pechmann反应合成7-羟基-4-甲基香豆素。考察了反应物间苯二酚与乙酰乙酸乙酯摩尔比,催化剂用量,反应温度,反应时间等因素对收率的影响,并对反应条件进行优化。结果表明,在间苯二酚与乙酰乙酸乙酯的摩尔比为1∶1.5(其中间苯二酚为0.1mol),反应时间为16 h,H3PW6Mo6O40/SiO2的用量为1.3 g,在油浴加热120℃左右的优化条件下,7-羟基-4-甲基香豆素的收率可达86.1%。

A new environmental friendly catalyst, H3PW6Mo6O40/SiO2 was prepared by sol-gel method. The optimum conditions had been found, that was, mass ratio of m （ H3PW6Mo6O40 ） ： m （ TiO2 ） was 40%, the calcining time was 3 h, and activated temperature was 150℃. The catalytic performance of Ha H3PW6Mo6O40/SiO2 in the synthesis of 7-hydroxy-4-methylcoumarin was examined, and the effects of various parameters were tested, which including reactants ratio, catalyst dosage, temperature and time. The optimum conditions were：molar ratio of resorcinol to ethyl acetoacetate was 1：1.5 （resorcino1,0. 1 mol）, catalyst dosage was 1.3 g, the reac- tion temperature was 120℃ ,and the reaction time was 16 h. H3PW6Mo6O40/SiO2 was an excellent catalyst for synthesizing 7-hy- droxy-4-methylcoumarin and its yield could reach over 86. 1%.