钴铝类水滑石液相选择性催化甲苯氧化合成苯甲醛

Selective Oxidation of Toluene to Benzaldehyde Catalyzed by Co / Al Hydrotalcite-like Materials in Liquid Phase

采用共沉淀法制备了不同Co/Al原子比的类水滑石(Cox/Al-LDHs,x=2、3和4)及其焙烧产物(Cox/Al-LDOs),用XRD、FT-IR、BET及ICP等技术手段分别表征了催化剂的结构、组成和比表面积,考察了对甲苯选择性氧化制苯甲醛的催化性能。结果表明,在优化条件甲苯0.6 mL(5.43 mmol),催化剂Co4/AlLDO 100 mg,过氧化氢叔丁醇21.7 mmol,溶剂乙腈10 mL,反应温度70℃,反应时间9 h下,甲苯的转化率为8.2%,苯甲醛的选择性达77.6%。催化剂重复使用7次后其催化活性和选择性未见降低,使用前后催化剂的XRD谱图基本不变,显示较好的结构稳定性。

Co/Al layered double hydroxides（LDHs） with different Co/Al ratios（ Cox/Al-LDHs, x = 2, 3 and 4） and their calcined samples （Cox/Al-LDOs） were prepared and characterized by XRD, FT-IR, BET and ICP techniques. These catalysts were studied for selective oxidation of toluene to benzaldehyde. The results indicate that under the optimized condition （0.6 mL （5.43 mmol） of toluene, 100 mg of Co4/Al-LDO, 21.7 mmol of tert-butyl hydroperoxide （ TBHP）, 10 mL of acetonitrile, reaction temperature 70 ℃, and reaction time 9 h ）, the conversion of toluene is 8.2% and the selectivity of benzaldehyde is 77.6%. Repeated runs indicate that these catalysts are stable up to 7 cycles without obvious change of the catalytic activity and selectivity.