Study On Hydrogenation Of 1,4-Butynediol Over Ni-based Catalyst

1,4-Butenediol?BED?and 1,4-butanediol?BDO?can be prepared by catalytic hydrogenation of 1,4-butynediol?BYD?,which could be further extended downstream to produce vitamin A,tetrahydrofuran?THF?,?-butyrolactone?GBL?,polytetramethylene glycolether?PTMEG?,biodegradable plastic polybutylene succinate Alcohol esters?PBS?that played an important role in medicine,textiles,military,and so on.Centerring on the hydrogenation of 1,4-butynediol,researchers carried out studies on the structure regulation and reaction kinetics of Pd-based and Raney Ni catalysts.It was found that the hydrogenation of BYD involved not only the hydrogenation of C?C and C=C,but also many side reactions such as isomerization,condensation,and hydrogenation of C=O.The surface properties of supports and catalysts as well as the presence and dispersion of active components such as Pd and Ni affected the hydrogenation performance of catalysts collaboratively.Up to now,systematic research on the relationship between the support and the performance of BYD hydrogenation was in lack.Centerring on the catalytic basis of BYD hydrogenation,this work was carried out on the influence of supports,additives and other factors on the hydrogenation performance over Ni-based catalysts.The surface structure of catalysts and its structure-activity relationship with the catalytic reaction was revealed.The main research contents were as follows:1.The performance of BYD hydrogenation on Ni/Al₂O₃,Ni/SiO₂,and Ni/ZrO₂ catalysts was compared.It was found that there existed Ni species in Ni/SiO₂ that interacted weakly with SiO₂ in large grains,and produced weakly adsorbed active hydrogen species,which resulted in optimal hydrogenation performance;There existed strong metal-support interactions in Ni/Al₂O₃,which resulted in strongly adsorbed hydrogen species that were not conducive to BYD hydrogenation under low temperature conditions;Less Ni species has exposed in Ni/ZrO₂ catalysts due to ZrO₂ migration coverage,thus the hydrogenation activity was lowest among these catalysts.2.The initial conversion rate of BYD was faster after introducing Mo to Ni/SiO₂,but it decreased obviously in the later period,which was attributed to the formation of coke due to the surface acid sites.The conversion rate of BYD over Ni-Cu/SiO₂,Ni-Co/SiO₂,Ni-La/SiO₂ was slower,and it was presumed that less weakly adsorbed hydrogen species were formed on the surface of the catalysts due to the interaction of the addition and support,thus,resulted in the poor catalytic activity.3.The study was performed on four catalysts with Zn loadings of 0,1%,3%, and 5%,respectively.It was found that the content of Zn not only had a certain influence on the hydrogenation activity of BYD,and with the improving of Zn loading,the yield of oxolan-2-ol decreased with the yield of BDO increasing,which was attributed to the formation of an alloy of Zn and Ni that promoted the adsorption and activation of C=O,and suppressed the formation of the cyclized product oxolan-2-ol followed by hydrogenating to BDO.