Study On The Regulation Of The Presence Of Ni In Ni/SiO₂ And Catalytic Hydrogenation Of 1,4-Butynediol

The 1,4-butynediol catalytic hydrogenation product is mainly 1,4-butanediol and 1,4-butenediol.They are important organic synthesis and fine chemical raw materials,and have a wide range of important applications in the fields of new polyester materials,paper,medicine,pesticides,textiles and household chemicals.In the early research,Raney-Ni and precious metal catalysts were used as the research core.Raney-Ni and precious metal catalysts were used by the former researchers as the core to study the hydrogenation reaction performance of 1,4-butynediol for catalyst composition and preparation method.At the same time,the kinetics and deactivation mechanism of the reaction were discussed.Based on the above analysis,the influence of metal loading,carrier type and preparation method on catalytic hydrogenation performance was studied with noble metal Pt/Pb as active component.However,the cost of precious metals is higher.Raney-Ni catalyst exhibits good catalytic performance in the hydrogenation of 1,4-butynediol due to its unique electronic properties,but it still has defects such as poor wear resistance of the catalyst and easy reaction deactivation.The effects of Ni-M electron effect of the catalyst and the surface properties of Ni-support on the hydrogenation performance of 1,4-butynediol were investigated by the introduction of metal auxiliaries,the regulation of the ratio of copper to nickel,and the modulation of the carrier Si/Al ratio(acid-base).The main research contents include:1.Ni/Si O2 and 15Ni5M/Si O2(M = Fe,Co,Cu)catalysts modified by different metal promoters were prepared by incipient impregnation method using Si O2 aerogel as supports.Different bimetallic catalyst structures were characterized by means of ICP,BET,XRD,H2-TPR,H2-TPD etc.and their promotion effect on the 1,4-butynediol hydrogenation performance were thoroughly investigated.It was found that different second metal element has various bimetallic synergy with the Ni species and the addition of appropriate amount of Cu into the Ni-based catalyst can not only improve the dispersibility of active Ni species,but also promote the metal reduction/ overflow ability as well as the H2 adsorption/activation capacity,which is benefit for the hydrogenation of 1,4-butynediol.2.Ni-Cu/Si O2 bimetallic catalysts with different Ni/Cu ratios(3:1,1:1,1:3)were prepared by supercritical drying method and incipient-wetness impregnation method.The catalysts were characterized by ICP,BET,XRD,H2-TPR,H2-TPD and NH3-TPD methods.The effects of different Ni/Cu ratios on the catalyst structure and the hydrogenation performance of 1,4-butynediol were investigated.The results show that the addition of a small amount of Cu can not only improve the dispersibility of Ni active species,but also the interaction between Ni-Cu bimetals improves the reduction performance of Ni O species and the hydrogen overflow capacity of active metal surface;15Ni5Cu/Si O2 catalyst has the most excellent bimetallic synergistic effect and exhibits the highest hydrogenation activity of 1,4-butynediol.3.Si O2-Al2O3 mixed oxide supported Ni catalysts with different Si/Al mole ratios(Ni/SA-x,x Si/Al=0,1,4,10 and 20)were synthesized by wet impregnation method and used for the hydrogenation of to 1,4-butanediol in an autoclave reactor.The catalysts were fully characterized by XRD,BET,TEM,H2-TPR,and NH3-TPD.The results revealed that the Si/Al ratio on the support significantly affected the properties of the acid sites and the size of the Ni particles on the catalysts.Among the tested catalysts,Ni/SA-10 exhibited excellent selectivity for 1,4-butanediol with 79.4% at 70 ? and 1.0 MPa H2 pressure when methanol solution with a 1,4-butynediol concentration of 10% was used as the substrate.