Efficient Epoxidation Of Mixed Olefins With Air Over Cobalt-Containing Porous Composite Catalyst Assisted By Microwave/Ultrasound

In recent years,the application of ultrasound/microwave has been extended to analytical chemistry,macromolecule chemistry,macromolecule materials,biochemistry,organic synthesis and environmental protection.Compared with the traditional heating method,the ultrasonic method generally has mild reaction conditions;the microwave method can provide higher reaction energy,shorten the reaction time,and increase the possibility of interaction between atoms.At the same time,epoxy compounds are widely used in various fields as important organic synthesis intermediates.Therefore,we try to replace the traditional heating by microwave/ultrasonic,promoting the epoxidation of mixed olefins with air to obtain epoxy products.Previous studies at our laboratory showed that ultrasonic method could activate catalysts very well.Using ultrasonic heating method,the epoxidation of several groups of mixed olefins was promoted obviously.Based on the above researches,we study the epoxidation of mixed olefins with air by microwave/ultrasonic heating as follows:1.Co Ox was loaded onto MOR by microwave heating impregnation method.The catalyst was used to catalyze the epoxidation of olefin with air.The effects of different metals,different synthesis methods and different metal loadings on the activity of the catalyst were discussed.The influence of reaction conditions on the reaction was also investigated,such as solvent,initiator,substrate amount,air flow rate and time.For the epoxidation of 6 mmol?-pinene in air,the conversion of?-pinene reached 92.7 mol%with the selectivity of 87.6%.2.The Zeolite@Co-MOF material was synthesized by microwave assembly and water vapor assisted crystallization,and used to catalyze the air epoxidation of diolefins(?-pinene and styrene).The catalytic activities of the catalysts with different metal loadings and different molecular sieves were discussed.The effects of initiators,reaction temperature,reaction time,solvent,catalyst amount and substrate amount were also discussed.We found that when the amount of cobalt added was only 7%,the conversion of?-pinene and styrene reached 90.2 and 90.0 mol%,with the epoxide selectivity of 97.2 and 89.2%,respectively.3.A highly active Zn_0.1Co₁-MOF bimetallic catalytic material was synthesized by hydrothermal rotation crystallization.The effects of synthesis method,metal,rotation speed,crystallization time and temperature were studied.It was found that the high activity Zn_0.1Co₁-MOF catalyst was obtained by rota-crystallization at 200°C and 150 rpm for 3 h.This catalyst was used to catalyze the air epoxidation of mixed olefins.The effects of reaction conditions were investigated,such as the amount of substrate,catalyst,solvent,reaction temperature,microwave power,reaction time and types of olefins.The effects of different reaction modes on the air epoxidation of olefins were also discussed.The results showed that the conversion of?-pinene and styrene reached 85.3 and 86.5 mol%with the epoxide selectivity of 93.8 and 93.6%,at 80°C and 30 m L/min air without initiator.