Studies On Epoxidation And Baeyer-Villiger Oxidation With The Influence Of Ultrasound

Selective oxidation of organic compounds is one of the most important reactions in petrochemical technology and has been studied extensively. The use of molecular oxygen is more commercially attractive than other oxidants, due to its low cost and environmental advantages. This paper aims to develop and establish a cleaning, effective and mild selective oxidation method. We proposed a metal Salen-oxygen catalytic system in which the cheaper and easily available catalysts could catalytically oxidize olefins and ketones to epoxide and ester compounds. We also introduced ultrasound to the oxidation reactions and investigated the effect of sonochemistry. Airlift loop reactor and ultrasound technique were innovatively coupled to form a new type sonochemical reactor - the ultrasonic airlift loop reactor in which we synthesizedε-caprolactone and epoxy cyclohexane. Finally, the supported catalysts were preliminary studied.An improved synthetic method for synthesis of Salen metal compounds from Schiff base and Mn(OAc)2·4H2O or Co(OAc)2 Mn(OAc)2·4H2O was firstly developed in this paper. Ultrasound has been utilized to optimize the reaction conditions of co-ordination, such as shortening reaction time (from 3~11 h to 0.5~2.5 h), reducing the reaction temperature (from reflux temperature 80℃to room temperature) and one-step adding the reactants instead of dropping the reactant. The influence of ultrasound source and ultrasound intensity has been studied.The aerobic oxidation of styrene to its epoxide catalysted by Salen-Mn(Ⅲ) complex was studied. The effects of central metal ion, the quantities of solvent, reaction temperature, reaction time, the molar ratios of isobutyradehyde and catalyst to substrate were investigated. It was found that the conversion of styrene can go up to 90.3% with a 84.5% selectivity of the epoxide styrene and 10.6% selectivity of benzaldehyde, when the reaction was run at 35℃for 4.5 h with the molar ratios of 2.5 and 0.1% of isobutyraldehyde and catalyst to the substrate, respectively.Co (Ⅱ) complexes with Salen Schiff-base ligands derived from ethylenediamine or (R,R)-1,2-diphenylethylenediamine and salicylaldehyde or 5,5-dibromo and...