Study On New Process Of TS-1 Catalyzed Butanone Ammoximation

Methyl ethyl ketone oxime is an important organic synthesis intermediate and chemical product.At present,methyl ethyl ketone oxime is mainly produced by ammoximation reaction with TS-1 as the catalyst in industry,but this process has some problems such as difficulty in separating the catalyst,plugging of membrane hole and long reaction time in industrial production.In this paper,the optimal reaction conditions were determined by systematic study of ammoximation process.The supported TS-1/SiO2 catalyst was prepared,and the fixed bed reactor was designed,in which the supported catalyst was filled,which greatly reduced the reaction time.The continuous process of ammoximation reaction was studied in a fixed bed reactor.(1)TS-1 catalyst was prepared by hydrothermal synthesis,and the supported TS-1 catalyst was prepared using SiO2 as the support.Both catalysts were characterized by specific surface area and pore size analysis,ultraviolet-visible reflection spectroscopy(UV-Vis),X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),and the characterization results laid a foundation for subsequent studies.(2)The optimal reaction conditions were determined by applying the self-made TS-1 catalyst to the intermittent reaction process of ammoximation.The reactant molar ratio hydrogen peroxide:ammonia=1:1.2:2,the reaction temperature was 70?,the quantity of TS-1 was 7.5 g/(mol butanone),the flow addition time was 1.5h,and the reaction continued for 1.5h after the flow addition,the mass of the solvent was m(tert-butanol):m(water)=1:1.In this reaction condition the best reaction effect was achieved and the yield of butanone oxime was 96.47%.(3)The continuous experiment of ammoximation reaction was carried out in a fixed bed reactor,and the process of separating the catalyst from the reaction solution was eliminated by filling the supported catalyst in the fixed bed reactor.When the reactant molar ratio butanone:ammonia:hydrogen peroxide=1:2.5:1.2,the reaction temperature was 65?,the inner diameter of the fixed bed reactor was 2 mm,and the space time of the reaction solution was 3 min,the fixed bed ammoximation reaction had the best reaction effect.The conversion rate of butanone reached 98.04%,and the selectivity of butanone oxime reached 97.75%.(4)The mechanism of ammoximation catalyzed by TS-1 was studied.The experimental results showed that the ammoximation process is more in line with the route of hydroxylamine.