Diphenylmethane Of Benzene And Benzyl Chloride Catalyzed By Fe-Sr-ZSM-5-SBA-15

Diphenylmethane is an important class of perfumes,dyes and pharmaceutical intermediates which is usually used as a kind of essential intermediate.Since diphenylmethane has these important and wide ranging applications,its synthesis method has also received much attention from many experts and scholars.The most common synthesis method of diphenylmethane is through Friedel-Crafts alkylation reaction using raw materials of benzene and benzyl chloride.The type of acid about traditional Friedel-Crafts alkylation reaction is B acid and L acid,but this kind of acid usually needs environmental protection treatment to acidic waste solution,and the catalyst selectivity is low,and the regeneration is difficult Therefore,to solve the problem of short diphenylmethane,developing and using a kind of new catalyst is necessary.With the continuous study of solid acid catalysts,ZSM-5 and other solid acid catalysts have been recognized by the researchers.In this experiment,the composite molecular sieve ZSM-5-SBA-15 catalysts were synthesized by in-situ method in the way of adding ZSM-5 to SBA-15system,and explore the influence of ZSM-5 complex amount on benzene and benzyl chloride reaction.According to the results,When the weight of ZSM-5:the weight of SBA-15 is 1:4,the performance of ZSM-5-SBA-15in the synthesis of diphenylmethane is the best.ZSM-5-SBA-15 composite zeolite can be modified by supersaturated impregnation method,and the different effect of metal modification conditions of M-ZSM-5-SBA-15（M is Fe,Sr,Cu,Ni,Al,Cr）composite zeolite with benzyl chloride have been investigated.The experimental results show that the metal introduction of Fe can improve the catalyst activity and improve the diphenylmethane conversion.Thus,Fe-ZSM-5-SBA-15 composite molecular sieve catalyst has the best effect in the reaction of benzyl chloride alkylation to synthesize diphenylmethane.The Fe-ZSM-5-SBA-15 composite zeolite catalyst can be characterized by XRD,FT-IR,BET,NH₃-TPD and Py-FTIR.The effects such as mass of Fe loading,the calcination temperature and calcination time on the reaction of benzyl chloride were investigated through the reaction result of the conversion of benzyl chloride and the selectivity of diphenylmethane.The results showed that the best catalyst for the reaction of benzyl chloride and benzene could be obtained under the conditions of Fe mass fraction of 10%,calcination temperature of550°C and calcination time of 4.5 h.Sr were introduced into Fe（10%）-ZSM-5-SBA-15 composite zeolite in the method of supersaturated impregnation,Fe-Sr-ZSM-5-SBA-15 was characterized by XRD,FT-IR,BET,NH₃-TPD,Py-FTIR and TG-DTA.The effects of Sr loading,catalyst calcination time and calcination temperature on the reaction properties of benzene and benzyl chloride were studied during the synthesis of diphenylmethane.The results showed that the best performance in the synthesis of diphenylmethane by alkylation of benzene and benzyl chloride was obtained when the mass fraction of Sr was 10%,the calcination temperature was 550°C,and the calcination time was 4.5 h.The catalytic performance of ZSM-5-SBA-15,Fe-ZSM-5-SBA-15and Fe-Sr-ZSM-5-SBA-15 composite molecular sieving catalysts in the alkylation of benzene and benzyl chloride to diphenylmethane was evaluated in the experiment.The experimental results show that under the conditions of reaction temperature is 75°C,reaction time is 30 min,n（benzene）:n（benzyl chloride）=6:1,no solvent,the Agent oil ratio is 10%,the conversion of diphenylmethane was 90.60%,the selectivity of diphenylmethane was 88.70%,and the yield of diphenylmethane was 80.30%.The regeneration performance of Fe-Sr-ZSM-5-SBA-15 composite zeolite catalyst was investigated in this aticle.The alkylation of benzene with benzyl chloride was carried out on the regenerated catalyst.The experimental results showed that the conversion of the raw material and the selectivity of the product did not change much after four times regeneration,the catalyst has certain stability.