Rational Prepration And Hydrogenation Performance Of Amorphous Alloy Catalysts

1,4-cyclohexanediol is an important chemical raw material and has been widely used in many fields.Owing to atomic economy,high-volume products,green environmental protection,and many other advantages,the catalytic hydrogenation of hydroquinone to 1,4-cyclohexanediol become the main production method of 1,4-cyclohexanediol.Most of the catalysts used in this process are Raney nickel and noble metal catalysts.However,many disadvantages are shown,such as polluting environments,harsh reaction conditions and poor activities during the process of used Raney nickel,as well as precious metal catalysts have the disadvantages of high preparation cost and complicated process,which can not meet the new requirements for hydrogenation of hydroquinone to 1,4-cyclohexanediol.Amorphous alloy catalysts have much higher catalytic activity than the corresponding crystalline catalysts,so the development of highly efficient amorphous alloy catalysts is the key to improve the yield of1,4-cyclohexanediol.In recent years,Ru-based catalysts and Ni-based catalysts have been favored by many scholars because of their superior catalytic hydrogenation performance.However,the content of active components of most Ru catalysts is too high and the process is complicated,which leads to high production cost of the catalyst,while the Ni catalyst has disadvantages such as poor stability,which seriously hinders its industrial application.This paper aims to prepare a new type of amorphous alloy catalyst with high activity,low cost and simple process,which provides a theoretical basis and experimental basis for the upgrading of hydroquinone catalytic hydrogenation technology.In this paper,a series of low-loading Ru-based and Ni-based supported amorphous alloy catalysts were prepared by chemical reduction method using NaY molecular sieves as carriers.the structure,composition and morphology of the catalyst phase were characterized by XPS,H₂-TPD,NH₃-TPD,XRD,SEM and ICP-OES.In the research of Ru-based catalysts,the results showed that the Ru catalysts prepared by the methods of reverse addition,W addition,ultrasonic assist,and coating of NaY with PEG ware more uniform and more active sites.In the research of Ni-based catalysts,since the active component Ni is an electron acceptor and B is an electron donor,it was found that the additive Sr modified the electronic structure of the Ni-B/NaY binary catalyst and promoted electron transfer.At the same time,NH₃-TPD and TEM characterization results show that the additive Sr can also regulate the acidity of Ni catalyst.In addition,the XPS and NH₃-TPD results of ternary Ni-based catalyst and quaternary Ni-based catalyst show that adding proper amount of Cu will partially cover the Ni particles,but this coating has less effect on the catalytic performance.The two series of catalysts prepared in this paper were applied to the hydrogenation of hydroquinone to 1,4-cyclohexanediol.Under the optimal reaction conditions,Ru-W-B/NaY-IUP（1500）_0.6（I represents reverse addition,U represents ultrasonic is used during preparation process,P means PEG used in the preparation process,M is the molecular weight of PEG,and m is the amount of PEG（g））catalyst used in the probe reaction showed that the conversion of benzene was99.7%,1,4-cyclohexanediol selectivity up to 92.3%,while the Ru loading in this catalyst was only 0.45 wt%.Under the same conditions,the hydrogenation of hydroquinone to 1,4-cyclohexanediol was catalyzed by Ni-Sr-B/NaY-U catalyst,the conversion of hydroquinone was 99.6%,and the selectivity of 1,4-cyclohexanediol was as high as 99.2%.When Ni-Sr-Cu-B/NaY-U was used in the reaction,the conversion of hydroquinone reached 99.4%,and the selectivity of 1,4-cyclohexanediol reached 98.6%,indicating that the catalytic performance was not significantly affected after adding an appropriate amount of Cu,but the stability of the Ni-Sr-Cu-B/NaY-U catalyst was significantly improved.After using for several times,the catalytic activity did not decrease significantly.