H_(2)O_(2)直接氧化甲苯合成邻/对甲酚

Synthesis of o-/p-cresol by direct oxidation of toluene with H_(2)O_(2)

以甲苯为底物、H_(2)O_(2)为氧化剂、乙腈为溶剂、过渡金属盐及其氧化物为催化剂,经液相氧化直接生成邻/对甲酚。考察催化剂、催化剂用量、溶剂、反应温度、氧化剂用量、氧化剂浓度和反应时间等工艺条件对甲苯转化率、邻/对甲酚选择性的影响,通过气相色谱和质谱进行结构表征。结果表明:以FeSO_(4)为催化剂、乙腈为溶剂,在H_(2)O_(2)与甲苯的物质的量之比为5、催化剂与甲苯质量比为0.10、反应温度80℃、反应时间1.0 h条件下,甲苯转化率达12.6%,邻甲酚选择性为25.6%,对甲酚选择性为25.1%。甲苯液相直接氧化法弥补了制备酚类化合物传统方法的不足,工艺流程短、原子利用率好,反应副产物为H_(2)O,无污染,是一条绿色清洁的工艺路线,为H_(2)O_(2)直接氧化制备酚类化合物提供理论基础。

o-/p-cresol was prepared by liquid phase direct oxidation,using toluene as substrate,H_(2)O_(2)as oxidant,acetonitrile as solvent,transition metal salt and its oxide over catalyst.The effects on the conversion of toluene and the selectivity of o-/p-cresol were investigated,including catalyst,solvent,temperature,oxidant amount,catalyst amount,oxidant concentration and time,the structure was characterized by gas chromatography and mass spectrometry.Results showed that under the conditions of n(H_(2)O_(2))∶n0(toluene)=5∶1,m(catalyst)∶m(toluene)=0.1∶1,temperature 80℃,time 1 h,the conversion of toluene was 12.6%,the selectivity of o-cresol reached 25.6%,the selectivity of p-cresol reached 25.1%.Compared with traditional methods,the direct oxidation of toluene in liquid phase made up the shortcomings for preparation of phenolic compounds,which had some advantages,such as short process,good atom utilization,and H_(2)O as by-product of reaction,which provided a theoretical basis for preparation of phenolic compounds by direct oxidation of H_(2)O_(2).