Synthesis Of TS-1/Cordierite Monolith Catalyst And Its Catalytic Performance Of Phenol Hvdroxylation

Hydroquinone is an important fine chemical intermediate,widely used in pesticide,spice,photosensitive material,dye,rubber and other fields.The diameter of crystal particle size of fine powder TS-1 zeolite with MFI topology is ranged from 200 nm to 500 nm,which has good catalytic performance and thermal stability.It is an ideal catalyst in the phenol hydroxylation.However,the catalyst is not easy to separate from the liquid phase after reaction,which is difficult to recycle.The key to solving this problem lies in the molding of catalyst,including granular TS-1 and TS-1 monolithic catalyst in this paper.The contrasting results show that granular TS-1 can be separated from the reaction liquid by filtering,but it is easy to wear.Meanwhile,with the increase of particle size of catalyst,activity of catalyst decreases significantly.TS-1 monolithic catalyst with high selective catalytic performance and convenient recovery has good application prospects.So the research of TS-1 monolithic catalyst has become the focus of this paper.This paper mainly includes two parts: first part: Preparation of fine powder TS-1 catalyst,granular TS-1 catalyst and TS-1 cordierite monolithic catalyst;Second part: Catalytic performance evaluation and deactivation and regeneration of TS-1 monolithic catalyst.Firstly,powdery TS-1 zeolite.was prepared by hydrothermal synthesis,and was applied to phenol hydroxylation.The results showed that the synthesized TS-1 particle size was about 200~500nm,the conversion rate of phenol and hydroquinone selectivity reached 26.2% and 98.2% when the molar ratio of phenol to hydrogen peroxide was 3:1 and reaction temperature was 60?,which showed high catalytic activity.With the increase of particle size of catalyst,activity of catalyst decreased significantly from the point of view of the catalytic performance of granular TS-1 catalyst.TS-1/ cordierite monolithic catalysts were prepared by in-situ hydrothermal synthesis,the result showed that the loading amount reached 4.76% under the optimal preparation conditions of Si / Ti molar ratio being 40,the content of the template being 0.2 times the molar amount of TEOS,molar ratio of water and silicon being 60,the crystallization temperature being 170?,the crystallization time being 72 h,but it can not meet the requirement of the hydroxylation reaction.TS-1 cordierite monolithic catalyst prepared by coating method was used to catalyze hydroxylation of phenol with hydrogen peroxide(30% aqueous solution),using commercially available TS-1 zeolite as the active component,cordierite ceramic honeycomb as the carrier,silica sol(30% aqueous solution)as a binder.The factors affecting hydroxylation of phenol were investigated in a homemade external circulation-forced batch reactor,such as reaction temperature,reaction time,TS-1 loading and molar ratio of phenol to hydrogen peroxide.The results show that firmness has been greatly improved after joining the silica sol.When the solvent is water,the molar ratio of phenol to hydrogen peroxide is 3:1,the mass ratio of water to phenol is 5:1,the mass ratio of phenol to TS-1 is 10:1,the reaction temperature is 70 ?and the reaction time is 6 h,conversion of phenol and selectivity of hydroquinone reach 28.8% and 95.4%,respectively.Characterization of deactivated TS-1 cordierite monolithic catalyst catalysts showed that carbon deposition is the main cause of catalyst deactivation.The catalytic activity of the deactivated TS-1 catalyst was basically restored to the level before the reaction through the high temperature calcination.