MOF-74负载磷钨酸催化剂的制备及其催化环己烯氧化制己二酸性能

PREPARATION OF MOF-74 SUPPORTED PHOSPHOTUNGSTIC ACID CATALYST AND ITS CATALYTIC PERFORMANCE FOR OXIDATION OF CYCLOHEXENE TO ADIPIC ACID

以Cu^(2+)为金属中心、2,5-二羟基对苯二甲酸为有机配体、磷钨酸(H_(3)PW_(12)O_(40),简称PTA)为活性组分,采用热溶剂法一步原位合成PTA负载量(w)为x%的一系列PTA/Cu-MOF-74催化剂(x%PTA@Cu-MOF-74,x=0,10,20,30,40)。采用傅里叶变换红外光谱、X射线衍射、扫描电镜和氮气吸附-脱附等表征手段对制得催化剂进行系统分析,同时对其催化环己烯氧化合成己二酸的活性进行测试。结果表明:PTA活性组分成功负载到Cu-MOF-74骨架中,并且MOF-74的骨架结构保持完整;在反应温度为80℃、反应时间为6 h、环己烯进料量为1 mL、双氧水(H_(2)O_(2)质量分数30%)进料量为4.5 mL、10%PTA@Cu-MOF-74催化剂用量为0.2 g的反应条件下,己二酸的产率最佳,为61.96%;相同试验条件下上述催化剂重复使用4次后,己二酸的产率仍达59.89%,与使用新鲜催化剂时相比降低幅度仅为3.3%。

With Cu^(2+)as the metal center,2,5-dihydroxyterephthalic acid as the organic ligand and phosphotungstic acid(H_(3)PW_(12)O_(40),PTA for short)as the active component,a series of PTA Cu-MOF-74 catalysts(x%PTA@Cu-MOF-74,x=0,10,20,30,40)with x%PTA loading(w)were synthesized by one-step hot solvent method.The catalysts were characterized by Fourier transform infrared spectroscopy,powder X-ray diffraction,scanning electron microscopy,nitrogen adsorption-desorption,and the catalytic activity of cyclohexene oxidation to adipic acid was tested.The results showed that the active component of PTA was successfully loaded into the Cu-MOF-74 skeleton,and the skeleton structure of MOF-74 remained intact.Under the reaction temperature of 80℃,reaction time of 6 h,the volume of cyclohexene of 1 mL,the volume of 30% H_(2)O_(2) of 4.5 mL,and the dosage of 10%PTA@Cu-MOF-74 catalyst of 0.2 g,the yield of adipic acid was the best(61.96%),and the yield of adipic acid was 59.89%after the catalyst was reused for 4 times under the same test conditions,which was only 3.3% lower than that of using fresh catalyst.