Study On The Acylation Of Anisole And Acetic Anhydride Catalyzed By Zeolites

P-Methoxyacetophenone（P-MAP）is an important aromatic ketone fine chemical product,which is mainly synthesized from anisole and acylating reagent acetyl chloride or acetic anhydride through Friedel-Crafts（F-C）acylation reaction.At present,the industry mainly adopts the homogeneous reaction process and batch tank reactor with Lewis acid（AlCl₃,etc.）as the catalyst to produce P-MAP.Although this process has high yield of acylated products,mild reaction conditions,cheap and easy-to-obtain raw materials,it also has problems such as corrosiveness of the catalyst,environmental protection,difficulty in product purification,difficult catalyst regeneration and complex process flow.Therefore,the development of high-efficiency solid acid catalysts and the corresponding fixed-bed continuous production process is of great practical significance for realizing the green production of P-MAP.The development and application of new catalysts is an inevitable trend of future production technology development.The research content of this paper includes the following points:（1）Four commercial zeolites（Y,MOR,Beta and MCM-22）and a single-layer MWW zeolite synthesized in the laboratory were selected as catalysts,respectively.The effects of reaction temperature,molar ratio of anisole and acetic anhydride,space velocity and zeolite structure on the catalytic acylation of anisole and acetic anhydride were studied in a fixed-bed reactor.Under the conditions of a pressure of 0.5 MPa,a reaction temperature of 220°C,a molar ratio of anisole to acetic anhydride of 5:1,and a mass space velocity of 2 h^-1,the results show that among the five zeolites with different structures studied,MCM-22 with MWW topology and the single-layer MWW zeolite exhibit excellent catalytic activity and catalyst stability,which is mainly due to the unique twelve-membered ring semi-supercaged structure on its surface promotes the rapid diffusion of reactants and products at the surface acid centers.（2）While further optimizing the synthesis method of single-layer MWW,the effect of zeolite extrusion molding on its catalytic performance for the reaction of anisole and acetic anhydride was preliminarily explored.The effects of parameters such as water-to-powder ratio,original zeolite powder mesh,binder and extrusion aid on the mechanical strength and acylation catalytic performance were mainly studied.The results show that under the conditions that the mass ratio of gouache to powder is 2,10%pseudo-boehmite as the binder,10%of 2 mol/L dilute nitric acid as the peptizer,and 3%of succulent powder as the extrusion aid,the strips can be extruded.The shaped catalyst has an optimum mechanical strength.However,the catalytic performance of the catalyst after molding is significantly lower than that of the original zeolite powder,which may be because the addition of the binder has a greater impact on the microenvironment of the surface acid center.