HKUST-1负载磷钨酸选择性合成乙二醇单叔丁基醚

Selective synthesis of ethylene glycol mono-tert-butyl ether with HKUST-1 load phosphotungstic acid

摘要:

采用一锅法制备HKUST-1负载磷钨酸（HPW）催化剂HPW@HKUST-1，在异丁烯与乙二醇选择性醚化合成乙二醇单叔丁基醚（EGME）中具有优异的催化性能。通过XRD、SEM、EDX、BET、ICP分析催化剂结构，采用吡啶红外（Py-IR）、酸碱滴定确定催化剂酸性。结果表明，HPW负载量的提高增加了催化剂Br?nsted酸活性位点，有利于提高反应物转化率，同时HPW负载量与催化剂孔径大小之间呈负相关性，孔径减小有利于提高目标产物EGME选择性。磷钨酸负载10%（以HKUST-1的物质的量为基准的摩尔分数）的HPW@HKUST-1催化剂活性较优，且具有良好的循环使用性，考察并确定该催化剂较佳工艺反应条件为：反应温度100 ℃，异丁烯与乙二醇摩尔比n(IB):n(EG)=6:1，催化剂用量为乙二醇质量的10%，乙二醇转化率97%，乙二醇单叔丁基醚选择性85%

Abstract:

HPW@HKUST-1 from phosphotungstic acid (HPW) supported in HKUST-1 was prepared with one-pot synthesis. It had excellent catalytic performance in the etherification of isobutene and ethylene glycol to ethylene glycol monotert butyl ether (EGME). The structure of catalysts was analyzed by XRD, SEM, EDX, BET and ICP, and the acidity of catalysts was determined by pyridine infrared (Py-IR) and acid-base titration. The results showed that enhanced HPW loading amount increases the Br?nsted acid site of the catalyst, which was beneficial to improve the reactant conversion. Meanwhile, there was a negative correlation between HPW loading amount and the pore size of the catalyst, and the decrease of pore size was conducive to improve the EGME selectivity. The HPW@HKUST-1 catalyst loaded with 10% phosphotungstic acid (Molar fraction based on the amount of substance in HKUST-1) has better activity and good recyclability. The optimum reaction conditions were investigated and determined as follows: reaction temperature was 100 ℃, the molar ratio of isobutene to ethylene glycol (n(IB):n(EG) )was 6:1, and catalyst dosage was 10% of the mass of ethylene glycol. The ethylene glycol conversion in optimal conditions reached 97% and EGME selectivity was 85% respectively.