Preparation Of Cs-P Acid-Base Bifunctional Catalyst And Its Application In Synthesis Of Methyl Acrylate

Methyl acrylate isa very important fine chemical raw material which is widely used in producing adhesive,flocculant,coating,textile,leatherette,drug,paper,and super absorbent resin and so on.One-step synthesis of methyl acrylatevia aldol condensation of methyl acetate with formaldehyde is anenvironmentally-friendly and greensynthesis process.Besides,the development of modern coal chemical industry leads to severeovercapacity of methanol andacetic acid.Further developing downstream product and elongate the chemical industry chain is aneffective way to solve this problem.Therefore,the research on the environmentally-friendly process is of important academic value and practical significance.The design and development of new high-performance catalysts is a key step for industrialization of the new process.Therefore,the key scientific problems in the design and preparation of acid-base bifunctional catalyst and the reaction process were studied.The main worksare as follows:(1)The Cs-P/?-Al2O3 catalysts were prepared using the method of incipient wetness and characterized by XRD,XPS,SEM,TEM,FT-IRand N2 adsorption-desorption.Cs-P/?-Al2O3 acid-base bifunctional catalyst belonged to mesoporous material.Cs and P reacted to form phosphate,metaphosphateand pyrophosphatewhich well dispersed on the surface of ?-Al2O3 support.The acid-base properties of catalysts have remarkable effects on the catalyst activity.The Cs-P/?-Al2O3 catalyst was characterized by CO2/NH3-TPD.The result indicated that P as an additive can regulate the amount of acid and base sites.The catalytic performance was evaluated using a fixed-bed microreactor.The influences of loading amount,support and calcination temperature on catalytic performance were studied in detail and the 10%Cs-5%P/?-Al2O3 catalyst calcined at 550°C showed the highest activity.The yield and selectivity of methyl acrylate is 44.3% and 91%,respectively.(2)The optimization of process parameters of the synthesis of MA was analyzed using RSM(response surface methodology).A second-degree polynomial model equation withhigh reliability and precision was suggested and used to analyze the interaction between the response of experimental design(the yield of MA)and the variables.(3)The catalytic performances of Cs-P/?-Al2O3 catalyst modified by metal oxides(W,Fe,Co,Cu,Zr and Ce)were investigated using a fixed-bed microreactor.It was found that the Cs-P-W/?-Al2O3 showed a higher selectivity and activity.From the characterization of microstructure of Cs-P-M/?-Al2O3(M = W,Fe,Co,Cu,Zr and Ce),it was revealed that the CsW2O6 structure was formed on the catalyst surface,which can promote the aldol condensation reaction.The long life of the Cs-P-W/?-Al2O3 catalyst was investigated.After running 1600 h,the regenerated catalyst showed no degradation in activity,indicating the Cs-P-W/?-Al2O3 catalyst had good stability and the use of recycle.(4)After the scale-up of catalyst preparation process,the catalytic performance of these catalysts was experimentally evaluated in a large-scale moving bed reactor(120 L/d).