Epoxidation Of Olefins By Molecular Oxygen Catalyzed By Rectorite-supported Active Metals

In recent years,the research on layered silicate clay minerals has mainly focused on the adsorption of heavy metals to achieve the purpose of decontamination.However,there are few studies on the use of layered silicate clay minerals for ion exchange and high temperature resistance as supports to catalyze olefins.As a kind of silicate clay minerals,Rectorite has the characteristics of high temperature resistance of mica layer on the one hand,and ion exchange characteristics of montmorillonite layer on the other hand.Reducing the size of the catalyst particles to expose more surface active sites has a greater advantage,so we tried to use the Rectorite after lyophilization as a carrier to support the active metal cobalt,and used it as a catalyst in catalytic epoxidation of olefins under air conditions to obtain epoxy compounds.Finally,it was found that no matter whether the rectorite carrier was treated at high temperature or not,its layered structure did not change,but the lamellar spacing of the rectorite treated with loaded metal would change significantly,which is more conducive to the metal loading of the Rectorite between the layers,and we have carried out a cyclic test on the catalyst for the epoxidation of olefins.After 5 times of reaction,the catalyst still had good catalytic effect.This work includes the following aspects:1.The cobalt-loaded Rectorite Co-Rec was synthesized by the traditional heating method using the cold-dried Rectorite as the carrier,and the catalytic epoxidation ofα-pinene was carried out using air as the oxygen source.The catalytic epoxidation was analyzed,the influence of the rectorite on its structure before and after metal loading is analyzed,the effect of cobalt supported on different supports on the epoxidation of olefins was compared,and the effects of different metals on the catalyst activity were discussed.The effects of reaction conditions such as reaction time,temperature,solvent,initiator,and substrate amount on the epoxidation reaction were also investigated.2.The quantum dots were synthesized by directly adding alkali at room temperature,and Rec-Co₃O₄ QDs was synthesized at room temperature by mechanical stirring.The influence of the existence of Rectorite on the structure of quantum dots was compared,and the effects of different kinds of alkalis and different cobalt sources on quantum dots cobalt tetroxide were investigated.The effects of different supports and alkali contents on the catalyst activity were discussed.Finally,the reaction conditions such as reaction temperature,time,initiator,catalyst content,and substrate content were explored.3.On the basis of step 2,Rectorite-supported bimetallic oxides were further synthesized.First,Co₃O₄ materials were synthesized,and then Rec-Co₃O₄-Sn O₂nanomaterials were synthesized by steam-assisted crystallization and high-temperature calcination.The materials were characterized by SEM,TEM,XPS,TG and other methods,and it was found that olefins could be oxidized without the need for co-catalysts.The effects of metals,different supports and different synthesis methods on the activity of catalysts were investigated,and the reaction conditions were also explored.