Sb-Mo复合氧化物单一相催化剂上的醇类氧化酯化

制备了三种单一相Sb-Mo-O系复合氧化物催化剂并用于C_1—C_4的醇类氧化反应,在反应条件下均可保持其晶体结构与酯化活性的稳定性。对氧化酯化来说,唯有以乙醇为原料时才可以高收率地获得酯类,其活性顺序为Y相>X相>Z相。异丙醇和异丁醇在同一催化剂上的反应结果,因反应温度高低而异,低温时发生脱氢反应,高温时发生脱水反应。利用体相晶格氧,乙醇氧化生成乙醛;而进一步氧化酯化生成乙酸乙酯则是利用气相氧。

Oxidative Esterification of Lower Alcohols over the single Phase Catalysts of Sb-Mo Binary Oxides

Three kinds of single phase (X, Y, Z) Sb-Mo-O binary, oxides were prepared and used for the oxidation of C_1—C_4 alcohols. All of these catalysts were stable under reaction conditions in both the crystal structure and the esterification activity. As for the oxidative esterification, they are effective only in the case of ethanol oxidation in an order of activity of Y phase>X phase>Z phase. A notable result is the fact that in the oxidation of 2-Propanol and 2-butanol, dehydrogenation and dehydration proceeded respectively at low and high temperatures over the same X phase or Y phase catalyst, indicating different active sites exist on the same catalyst but act at different temperatures. On reduction of the catalyst by a mixture of ethanol:nitrogen=1:4, it is found that acetaldehyde formation is caused by lattice oxygen, whereas ethyl acetate formation by further oxidative esterification is caused by gaseous oxygen.