苯乙烯存在下苯乙炔选择性加氢过程的研究

用高压反应釜对一种骨架Ni催化剂和八种Pd/Al₂O₃催化剂在苯乙烯环境下，对连串反应苯乙炔的选择性加氢性能进行了实验评价。通过一系列实验考察了催化剂活性组分负载量、反应温度、反应压力、反应时间和搅拌速率对反应结果的影响。反应结果的评价指标为苯乙炔转化率、苯乙烯收率和二者的综合。研究结果表明，骨架Ni催化剂的活性和选择性均较差，不适宜用作苯乙烯环境下的苯乙炔加氢过程。对Pd/Al₂O₃型催化剂而言，较低的反应温度和微正压的反应条件对苯乙炔的选择性加氢有利；延长反应时间无助于苯乙炔转化率的提高，相反却会导致苯乙烯收率的迅速降低；提高搅拌速率可以消除相间扩散传质对反应过程的影响，因此对苯乙炔的选择性加氢是有利的。另外，在实验研究的反应条件范围内，苯乙炔的转化率似乎存在一个极限值，分析认为这可能是由于催化剂的比表面积和活性组分负载量太高引起的。

Selective hydrogenation of phenylacetylene in the presence of styrene

The catalytic performance of a Raney nickel catalyst and eight Pd/Al_2O_3 catalysts in selective hydrogenation of phenylacetylene in the presence of styrene was studied using a high-pressure reactor. The influence of active component loadings, reaction temperature, reaction pressure, reaction time and the stirring velocity on the hydrogenation results,including phenylacetylene conversion and yield of styrene, were investigated. The results showed that Raney nickel catalyst is not suitable for selective hydrogenation of phenylacetylene due to its low activity and selectivity. Low reaction temperature and slightly positive pressure favored Pd/Al_2O_3 catalysts to achieve higher phenylacetylene conversion and styrene yield. Phenylacetylene conversion did not increase with reaction time, while styrene yield declined with reaction time. Increasing stirring velocity is helpful to elimination of the limitation of mass transfer on the reaction. The investigation results also showed that there seemed to be a limitation for phenylacetylene conversion, at which point no improvement on phenylacetylene conversion could be achieved by changing reaction conditions, which may be explained by high active component loadings and large surface area of the catalysts.