Preparation Of TS-1/Fe₃O₄ Magnetic Catalyst And Its Catalytic Activity On Phenol Hydroxylation

Hydroquinone and Catechol,important pharmaceutical intermediates,are widely used in the fields of rubber,dyes,antioxidants,medicines,pesticide developers and so on.Traditional synthesis processes mainly include o-chlorophenol hydrolysis,aniline oxidation,cyclohexanone method,et al.But the processes listed above have some problems such as complicated process routes,many by-products,and high raw material prices.Hydroxylation of phenol by H2O2 has the advantages of mild reaction conditions,few by-products and simple process,the separation of fine catalysts is one of the difficulties of this technology.In this paper,the hydroxylation process is systematically studied on Fe3O4 and TS-1 catalysts.In view of the problem of catalyst separation and regeneration during the reaction,Fe3O4/TS-1 magnetic catalyst is prepared,and its catalytic performance for phenol hydroxylation was investigated.The main research content is as follows:TS-1 catalyst was prepared by hydrothermal synthesis,and a series of characterizations were performed on the catalyst,including X-ray powder diffraction(XRD),scanning electron microscope(SEM),Fourier transform infrared spectroscopy(FT-IR),ultraviolet visible reflection spectrum(UV-Vis),etc.The results show that it has an MFI topology structure with a uniform particle size of about 100 nm.The prepared catalyst was applied to phenol H2O2 hydroxylation reaction system,and the reaction conditions were systematically studied.The optimal conditions are listed as follows:the reaction temperature was 70?,water as the solvent,the H2O2 solution was fed for 60 minutes,the amount of TS-1 catalyst was 10 g/mol phenol,and the reaction time was 60 minutes.Under this process condition,the conversion rate of phenol reached 77%,the selectivity of diphenol reached 99%,and the ratio of catechol to hydroquinone is 0.67.Fe3O4 powder is used to catalyze the hydroxylation reaction as Fe3O4 has the advantages of low price and easy to separate.The reaction conditions are systematically investigated.The optimal reaction conditions were determined as follows:the reaction temperature was 60?,water as solvent,the H2O2 solution was fed for 60 minutes,the amount of Fe3O4 catalyst was 10 g/mol phenol,and the reaction time was 60 minutes.Under this process condition,the phenol conversion rate reached 49%,the selectivity of diphenol is 90%,and the ratio of catechol to hydroquinone is 1.02.TS-1/Fe3O4 magnetic catalyst was prepared and applied in hydroxylation process.The reaction was performed under the conditions that is optimal when TS-1 was used as the catalyst.Compared with Fe3O4,the magnetic catalyst showed higher phenol conversion and diphenol selectivity.The catalyst can be separated by applying a magnetic field,which provides guidance for the industrial application of phenol hydroxylation..