Preparation Of Acidic Cu-BTC And Its Catalysis For Claisen-Schmidt Reaction

In order to solve the difficult separation and recycling of homogeneous catalysts in the synthesis of chalcone,in this paper,controllable preparation of metal-organic framework material Cu-BTC was prepared by solvothermal method and steam-assisted conversion method respectively,the preparation process of Cu-BTC was optimized by adjusting reaction parameters,and the catalytic performance of the optimized catalysts Cu-BTC?S1,S2,S3?heterogeneously catalyzed Claisen-Schmidt reaction was further studied,and the chalcone products with higher purity and better yield were synthesized.The crystal structure of Cu-BTC catalyst was analyzed by XRD and FT-IR,and the thermal stability of Cu-BTC catalyst was tested by TGA,the morphology of Cu-BTC catalyst was observed by SEM,as well as the specific surface area and pore size distribution of Cu-BTC catalyst was measured by N₂ isothermal adsorption-desorption experiment,the surface acidity and acid intensity distribution of Cu-BTC catalyst were determined by NH₃-TPD,Finally,the chemical structure and composition of chalcone were determined by FT-IR,¹HNMR,¹³CNMR,and HRMS.In controlled preparation experiments using copper nitrate and H₃BTC[n(Cu²⁺):n?H₃BTC?=1.5:1]as raw materials,the better preparation conditions for the solvothermal synthesis of Cu-BTC?S1?were as follows:volume ratio of H2O:EtOH:DMF=1:1:1,ultrasonic pre-treatment for 10min,reaction temperature of 120?,and reaction time of 12h.The better preparation conditions for the solvothermal synthesis of Cu-BTC?S2?were as follows:volume ratio of H2O:EtOH=1:1,magnetic stirring pre-treatment of 30min,reaction temperature of120?,and reaction time of 12h.The better preparation conditions for steam-assisted conversion of Cu-BTC?S3?were determined:volume ratio of H₂O:EtOH=1:1,reaction temperature of 140?,the reaction time of 12h,and the amount of medium zeolite is 45g/5ml solvent.In the synthesis of chalcone catalyzed by Cu-BTC,the better process conditions of Claisen-Schmidt condensation reaction were as follows:the molar ratio of benzaldehyde to acetophenone was 1:1,the weight ratio of catalyst to reaction material was 4.8wt.%,the reaction temperature was 140?,reaction time was 10h,the yields of chalcone was64.6%-83.8%.The experimental results of the catalyst recyclability showed that the Cu-BTC catalysts still had good catalytic activity after five times of recycling.Furthermore,Cu-BTC?S2?with higher acid content and interconnective porous structure had higher catalytic activity than the other two Cu-BTC catalysts.The research result showed that the catalytic performance of Cu-BTC was determined by the acid content and pore structure of the catalytic material.