Preparation Of Bimetallic Catalysts And Their Catalytic Amination Of Diethylene Glycol

Natural gas has been a vital energy source for the development of our country,and before it can be used extensively,it must be purified and free of H2S,CO2,organic sulfur,and other acidic gases.Tertiarybutylaminoethoxyethanol(TBEE)is an efficient selective desulfurization solvent,and its conventional synthesis method,which relies on tert-butylamine and 2-chloroethoxyethanol as raw materials,will result in the synthesis of haloalkyl by-products and reactor corrosion.Postprocessing and complex purification operations significantly increase production costs.In contrast,diethylene glycol,a byproduct of the hydration of ethylene oxide to make ethylene glycol,is reacted with tert-butylamine to produce TBEE,which has the advantages of being clean,effective,and environmentally friendly.There are few reports on this approach currently,and the yield of target product isn’t enough.Consequently,developing a catalyst system suitable for this reaction to improve reaction yield is of great significance.Compared to single metal catalysts,bimetallic catalysts provide better catalytic activity and stability.Herein,Ni and Cu were used as active components,a series of NiCu/Al2O3 catalysts were prepared.The effects of preparation conditions such as preparation method,metal loading,calcination temperature,and reduction temperature on catalytic activity were explored in a batch reactor.XRD,N2 adsorption-desorption,SEM,TEM,XPS,and H2-TPR were employed to investigate the structure-activity relationship of catalysts.Cycle performance of the catalyst was examined,and a plausible reaction mechanism for the reaction of diethylene glycol with tert-butylamine was proposed.The optimal conditions in the autoclave were then determined by varying reaction parameters(such as H2 pressure,reaction temperature,reaction time,stirring speed,reactant molar ratio,and catalyst amount).Under optimal conditions,the conversion of diethylene glycol was 89.6%,and the selectivity of TBEE was 84.6%.Following the operation of extrusion molding,the catalyst was applied to a fixed-bed reactor,the optimal process conditions for the reaction(including feed rate,reaction temperature,reaction pressure,molar ratio of reactants,and catalyst amount)were explored.Under optimal conditions,the conversion of diethylene glycol was 59.4%,and the selectivity of TBEE was 57.5%.In this work,the activity and cycle stability of catalysts in the amination reaction of diethylene glycol had been significantly improved through the effective regulation of catalyst system and the optimization of reaction apparatus and process conditions,which offered a novel idea for the further design and development of high-performance industrial heterogeneous catalysts as well.