Synthesis And Modification Of Mordenite For Carbonylation Of Dimethyl Ether

Ethanol is an important chemical basic raw material,and can be used as fuel and fuel additive.Therefore,the exploration and improvement of ethanol production technology has become a research hotspot.The synthesis of dimethyl ether(DME)from synthesis gas,the synthesis of methyl acetate(MA)by DME,and the synthesis of ethanol by hydrogenation of MA are the most promising ethanol production routes for industrial applications.At present,this process route is restricted by the catalytic activity of the DME carbonylation reaction.In this paper,mordenite catalysts were prepared by hydrothermal synthesis and modified with template,Ni and Ag,respectively.The catalysts were characterized by Ar adsorption/desorption,XRD,SEM,HRTEM,ICP-OES,27 Al MAS NMR,29Si MAS NMR,NH3-TPD,H2-TPR,Py-IR,CO-TPD.In the hydrothermal synthesis process,tetraethylammonium hydroxide(TEAOH)was added as template to synthesize nano-mordenite catalysts.The addition of the template agent reduced the diameter of the mordenite catalyst particles,increased the specific surface area,and increased the amount of Bronsted acid site.Compared with H-MOR-0T,the specific surface area of H-MOR-1T was increased by 60%,the crystallinity was increased by 124%,the amount of Br(?)nsted acid site was increased and the catalytic performance was improved.Under the evaluation conditions of 473K,1.0MPa,2400 ml/(g·h)space velocity,the conversion of DME and the selectivity of MA could reach 50%and 98%over H-MOR-1T.A series of Ni-MOR catalysts with different Ni content were prepared by pretreatment method.During the synthesis process,Ni atoms entered the mordenite framework without destroying the structure of mordenite,and adjusted the distribution of Al atoms,which increased the amount of strong acid sites and catalytic activity.Under the evaluation conditions of 473K,1.0MPa,2400 ml/(g·h)space velocity.The conversion of DME and the selectivity of MA could reach 44%and 100%over 1Ni-MOR(Ni 0.026 wt%).The Ag-MOR catalysts with different Ag wt%were prepared by ion exchange method.Ag atoms entered the mordenite pores and evenly dispersed.Medium strong acid sites were formed in Ag-MOR,while the amount of weak acid sites decreased and the strong acid sites increased.After Ag modification,the amount of Ag-MOR Bronsted acid sites increased,and a large amount of CO adsorption sites were generated.The DME carbonylation activity was enhanced by the work together of two.4Ag-MOR(Ag 8.3 wt%)showed the highest activity at 473K,1.0MPa,9280 ml/(g·h)space velocity,the DME conversion rate could reach up to 96%,the selectivity of MA could reach up to 100%,highest MA yield can reach 0.86 g/(gcat·h).