H2SO4-SiO2催化7-羟基-4-甲基香豆素的无溶剂合成

分别制备了4种H₂SO₄-SiO₂。以H₂SO₄-SiO₂为催化剂，乙酰乙酸乙酯和间苯二酚为原料,通过Pechmann反应，在无溶剂条件下,催化合成了7-羟基-4-甲基香豆素。以4种不同H₂SO₄-SiO₂、催化剂用量、反应时间、反应温度和反应原料的物质的量比设计了五因素四水平的正交试验，得到负载硫酸催化反应的最佳条件：n(H₂SO₄)∶n(Si)=0.75∶1，n(间苯二酚)∶n(乙酰乙酸乙酯)=1∶1，催化剂用量0.35 g（间苯二酚0.04 mol），反应时间95 min，反应温度105 ℃，最佳条件下产品收率为72.4%。

Solventless synthesis of 7-hydroxy-4-methyl coumarin catalysed by H2SO4-SiO2

Four types of H₂SO₄-SiO₂ catalyst were prepared. 7-Hydroxy-4-methyl coumarin was synthesized from ethylacetoacetate and resorscinol over H2SO4-SiO2 catalyst without presence of solvent. Orthogonal experiments were carried out using catalyst types, catalyst dosage, reaction time, reaction temperature and mole ratio of reactants as the elements. The optimum condition was obtained as follows: n(H₂SO₄)∶n(Si)=0.75∶1，ethylacetoacetate-to-resorscinol mole ratio=1∶1, catalyst dosage=0.35 g［while n(resorscinol)=0.04 mol］, reaction temperature 105 ℃, reaction time 95 min. 7-Hydroxy-4-methyl coumarin yield of 72.4% was obtained under the optimal condition.