助剂对Ni/SiO2催化剂1,4-丁炔二醇加氢性能的影响

Effect of promoters on Ni/SiO2 catalytic performance for hydrogenation of 1,4-butynediol

通过分步浸渍法在Ni/SiO 2催化剂中分别引入Zn、Cu、La、Mo、Co金属助剂,结合N 2物理吸附-脱附、XRD、H 2-TPR和NH 3-TPD等表征手段研究金属助剂对1,4-丁炔二醇加氢性能的影响。结果发现,Mo的引入使Ni/SiO 2催化剂的初始活性大幅增加,但反应2 h后活性下降,归因于催化剂表面酸中心使催化剂积炭失活;引入Cu、La及Co后的催化剂活性较低,推测是由于催化剂表面产生强吸附氢物种,不利于1,4-丁炔二醇加氢反应进行;与其他样品相比,Zn的引入使催化剂保持了Ni/SiO 2催化剂高的1,4-丁炔二醇加氢活性,同时可有效降低产物中2-羟基四氢呋喃副产物含量,提高目标产物1,4-丁二醇收率。

Ni/SiO 2 catalysts modified with different metal promoters,such as Zn,Cu,La,Mo and Co,were prepared by impregnation method.These catalysts were characterized by N 2 physical adsorption-desorption,XRD,H 2-TPR and NH 3-TPD methods,and tested in hydrogenation of 1,4-butynediol.The results showed that the initial activity of Ni/SiO 2 catalyst increased greatly with the introduction of Mo,but decreased after 2 h of reaction,which was attributed to the carbon deposition caused by acid sites on the catalyst surface.The low activity of Ni/SiO 2 catalysts after doping with Cu,La and Co,was presumably because strong adsorbed hydrogen species appeared on the surface of catalyst,which was not conducive to the hydrogenation of 1,4-butynediol.Compared with other samples,Zn-doped Ni/SiO 2 catalyst could keep as high activity for hydrogenation of 1,4-butylenediol as the un-doped one.Meanwhile,the content of 2-hydroxytetrahydrofuran as a by-product was effectively reduced,and the yield of target product 1,4-butanediol was improved.