Study On Catalyst For Preparation Of Oxide Styrene By Epoxidation Of Styrene

As an important organic intermediate,oxide styrene is widely used in various fields of fine chemicals such as spices,cosmetics and pharmaceuticals,so the preparation of ethylene oxide is a hot research topic.The study of epoxidation of styrene mainly includes two aspects,one is the study of oxidation system with oxidant as research object,the other is research of catalysis system with catalyst,and more research on catalysis system.So far,the oxidation methods used in the epoxidation of styrene include halogenated alcohol ring oxidation,inorganic acid-salt epoxidation,organic peroxide acid epoxidation,alkyl hydrogen peroxide epoxidation,hydrogen peroxide epoxidation,air or oxygen epoxidation,etc.,which can be used in industrial production.The catalysts used in styrene epoxidation include metal catalysts,metal oxides catalysts,metal organic complexes catalysts,zeolite catalysts and heteropoly acid catalysts.In this paper,the transition metal-lysine salen complexes catalysts,MCM-41 loaded NiO nanoparticles catalysts and ultrathin porous nano flake NiO catalysts were used as catalysts for styrene epoxidation,and these catalysts have achieved good catalytic effect.At the same time,various characterization methods(X-ray diffraction,scanning electron microscope,transmission electron microscope and nitrogen adsorption-desorption test)were used to explain the surface morphology,crystal characteristics and texture characteristics of catalysts,and the relationship between these characteristics and their catalytic activity was discussed.The article draws the following conclusions:(1)In this paper,the catalyst of transition metal lysine salen complexes exhibited better catalytic activity to styrene epoxidation compared with other transition metal salen complexes prepared by amine or APTES.The conversion rate of styrene reached 91.51%,and the selectivity of ethylene oxide was 91.99%.(2)The load of NiO nanoparticles does not change the structure of well-order mesoporous pore structures of MCM-41,and its hexagonal pore mesostructure is preserved.The 6Ni-MCM-41 showed higher catalytic activity and stability than the pure nio nanoparticles.The conversion rate of styrene and the selectivity of ethylene oxide were 90.38% and 91.17%,respectively.This benefits from the dispersion of the carrier MCM-41 to NiO nanoparticles and the synergistic effect of the two.(3)The ultrathin porous nano flake NiO prepared have good crystallinity,and the hydrothermal temperature of 150 °C is propitious to the growth of the(111)plan of NiO crystals,and the higher calcination temperature is also propitious to the growth of the(111)plan of NiO crystals.