Study On The Preparation, Modification And Catalytic Oxidation Reaction Of Titanium Silicon Molecular Sieve TS-1

TS-1 molecular sieve is a novel catalyst with MFI topology composed of silicon oxytetrahedron and titanyl tetrahedron.Due to its unique catalytic oxidation performance,TS-1 molecular sieve has attracted extensive attention since it was successfully synthesized in the 1980s.In particular,the oxidation system composed of TS-1/H₂O₂ can realize selective oxidation reaction of various organic substances?such as hydroxylation of benzene and phenol,oxidation of aniline,etc.?.The reaction system has mild conditions,simple and safe operate,and the by-product is water-free to the environment,which conforms to the concept of "green chemistry" and has attracted the attention of many researchers.At present,a lot of research work has been done on the synthesis method and application of TS-1 molecular sieve,and remarkable results have been achieved.However,there are still some challenges to the high yield and high selectivity catalytic oxidation reaction of some aromatic compounds.This paper mainly includes three aspects of work:?1?synthesis,modification,modification of TS-1 molecular sieve.?2?Hydroxylation of anisole.?3?A method for oxidizing aromatic amines to azoxybenzenes was developed.1.Synthesis,modify,and modify TS-1 molecular sieves.The TS-1 molecular sieve was synthesized by a simple method.In the synthesis process,the molecular sieves with different pore sizes were synthesized by replacing the template agents with different molecular weights,and the molecular sieves with different Si/Ti molar ratios were synthesized by adjusting the molar ratio of the silicon source to the titanium source;The molecular sieves were modified by alkali and metal.2.Hydroxylation of anisole.The hydroxylation of anisole was carried out with the synthesized molecular sieve as catalyst and hydrogen peroxide as oxidant.It was found that the template was tetrapropyl ammonium hydroxide,the molar ratio of Si/Ti was 80.and the hydroxylation of anisole with Cd and Cu modified titanium silicate zeolite showed good selectivity.3.A method for the oxidation of aromatic amines to azoxybenzenes was developed.The reaction conditions were optimized by the oxidation reaction of aniline in the oxidation system of TS-1/H₂O₂.The optimized conditions were obtained:TS-1?80?as catalyst,acetone as solvent,molar ratio of H₂O₂ to substrate was 2,water bath 60°C.The expansion of the reactants under the most conditions shows that the oxidation system has good group compatibility,but the steric hindrance has a great influence on the reaction,and the yield of the target product is above 50%.