常压下碳纳米管负载钯催化剂上肉桂醛选择性加氢

以Pd(NH3)4Cl2为Pd前体,采用传统的渍浸法制备了Pd/碳纳米管(CNTs)催化剂,并在常压下研究了反应温度、反应时间、溶剂和促进剂(酸、碱、盐等)对肉桂醛液相选择性加氢性能的影响。实验结果表明,在常温、常压下,Pd/CNTs催化剂具有良好的肉桂醛选择性加氢性能,催化活性和苯丙醛的选择性受反应条件、溶剂和促进剂的影响。使用极性溶剂能提高催化剂的活性,但苯丙醛的选择性有所降低。在反应体系中添加适量的弱碱NaOAc或弱酸HOAc均能显著提高Pd/CNTs催化剂的选择性加氢性能。在Pd/CNTs催化剂用量0.36g、肉桂醛用量8.0mmol、无水乙醇用量19.0mL、240min、30℃、常压条件下,当添加0.025～0.050mmol的NaOAc时,肉桂醛的转化率和苯丙醛的选择性分别达到93.3%～94.8%和92.0%～94.9%。

Selective Hydrogenation of Cinnamaldehyde over Carbon Nanotubes Supported Pd Catalysts Under Atmospheric Pressure

Pd/carbon nanotubes(CNTs)catalyst was prepared by a conventional impregnation method with Pd(NH3)4Cl2 as Pd precursor.Effects of reaction temperature,reaction time,solvents and promoters(acid,base and salt)on selective hydrogenation of cinnamaldehyde(CMA)over the Pd/CNTs catalyst were studied under atmospheric pressure.Results showed that properties of the Pd/CNTs catalyst were good for the catalytic hydrogenation of CMA.Use of polar solvent could increase the catalyst activity in CMA hydrogenation,while decreased selectivity to HCMA slightly.Promoters,such as HOAc and NaOAc,could improve performance of Pd/CNTs catalyst in the selective hydrogenation.Under the conditions of Pd/CNTs catalyst 0.36 g,promoter NaOAc 0.025-0.050 mmol,CMA 8.0 mmol,ethanol 19.0 mL,240 min,30 ℃ and atmospheric pressure,conversion of CMA and selectivity to HCMA in the selective hydrogenation of CMA could reach 93.3%-94.8% and 92.0%-94.9%,respectively.