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采用浸渍法对无定形ZnO分别用稀H2SO4和(NH4)2S2O8溶液处理,制备了SO42-/ZnO和S2O28-/ZnO固体酸.通过固体离子交换法制备了Cu(Ⅰ)/SO42-/ZnO和Cu(Ⅰ)/S2O82-/ZnO两种催化剂,并采用XRD,FTIR,TPD和TPR等进行了表征.研究结果表明,用稀H2SO4和(NH4)2S2O8溶液分别浸渍处理无定形ZnO,经过500~600℃高温焙烧后得到的SO24-/ZnO和S2O82-/ZnO固体酸表面形成了Zn3O(SO4)2物种;py-FTIR结果表明,两者均具有B酸中心和L酸中心,进一步的NH3-TPD研究结果证明,制备的固体酸NH3脱附峰均出现在543℃附近,属于高强度固体酸.结构分析认为,由于SO24-强烈的电子诱导作用,SO42-和ZnO形成的桥式配位物种产生了B酸中心和L酸中心,而其螯合配位形成的物种没有酸性.SO24-/ZnO和S2O82-/ZnO固体酸与CuCl进行离子交换所制备的Cu(Ⅰ)/SO42-/ZnO和Cu(Ⅰ)/S2O82-/ZnO催化剂的Cu(Ⅰ)易于还原,对甲醇氧化羰基化合成碳酸二甲酯(DMC)表现出较高的活性和选择性,DMC选择性为98.3%,时空收率可达到1.9g(g.h).
The SO42- / ZnO and S2O28- / ZnO solid acids were prepared by impregnation of amorphous ZnO with dilute H2SO4 and (NH4) 2S2O8 solutions, respectively. Cu (I) / SO42- / ZnO and Cu (Ⅰ) / S2O82- / ZnO catalysts were prepared and characterized by XRD, FTIR, TPD and TPR.The results show that amorphous ZnO is impregnated with dilute H2SO4 and (NH4) 2S2O8 solution, The pyrolysis of Zn3O (SO4) 2 on the surfaces of SO24- / ZnO and S2O82- / ZnO solid acid calcined at high temperature of 600 ℃ showed that both of them had B acid sites and L acid sites, and further NH3- TPD results show that the prepared solid acid NH3 desorption peak appear in the vicinity of 543 ° C, belong to the high-strength solid acid structural analysis shows that due to SO24-strong electronic induction, SO42- and ZnO bridging coordination species The acid sites of B acid and L acid sites were formed, but the species formed by chelate coordination did not have acidity.Cu (Ⅰ) / SO42- / ZnO prepared by ion exchange of SO42- / ZnO and S2O82- / ZnO solid acid with CuCl And Cu (Ⅰ) / S2O82- / ZnO catalyst Cu (Ⅰ) is easy to reduce, the oxidation of carbonylation of methanol synthesis of dimethyl carbonate (DMC) showed high activity and Selectivity, selectivity to DMC was 98.3% and space-time yield was 1.9 g (g · h).