Synthesis Of Salen Complexes And Their Catalysis Research Of Epoxidation Of Carbon-Carbon Double Bond

In this paper, the different metal complexes, M-salen complexes are synthesized by one-step and sub-step. The main metal centers are respective manganese, iron, cobalt, copper and so on. The salen ligands and M-salen complexes which contain imino group are successfully synthesized, which can be proved by comprehensive analysis, such as Elemental Analysis, IR, UV-Vis, NMR Spectroscopy and Thermal Gravimetric Analysis and othercharacterization methods. In this paper, we research the M-salen complexes catalyzing carbon-carbon double bonds in vegetable oil epoxidation performance. We study different reaction conditions effect on the epoxidation such as vegetable oils, reaction time, reaction temperature, oxidants and so on. We explore how the structure of catalysts and the metal active center affect the epoxidation of oils. And we investigate how the epoxy effect changes with the help of ultrasonic. Compared with water heat condition, ultrasonic can greatly improved epoxy effect and the best ultrasound power is 300 W. Epoxy value increases from 2.2 g/100g to 4.0 g/100g. Ultrasonic accelerates epoxidation of soybean oil and the reaction time greatly shortens to 0.5 h. The amount of catalyst is only 0.5%. The epoxy vegetable oils are analyzed by IR, TGA and so on. We propose the mechanism of M-salen catalyzing epoxidation of vegetable oils and verify the rationality of the mechanism through quasi UV and IR and computer simulation.The M-salen complexes are immobilized at large hole, middle hole (such as HMS and MCM), and microporous zeolites by direct dipping method and miscellaneous coordination method. We explore their catalysis performance on epoxidation of carbon-carbon double bonds in vegetable oil and carry out repeat experiments. Though the conversion rate of the immobilized catalyst was lower than the catalyst without being immobilized, the selectivity increased. Mn-salen complexes immobilized at HMS Zeolites shows the best epoxidation effect with the conversion rate of 59.7% and the selectivity of 75.5%. And they can be reused five times remaining good catalytic performance. Especially, the catalytic performance of the miscellaneous coordination immobilized catalyst is better than what are impregnated directly, because of the less lost of catalyst active site. And the good catalysts were characterized by XRD, IR, BET and so on. Combined with the size of the vegetable oil molecules, we can know the pore size is a major factor affecting the epoxidation of vegetable oil.Traditional acid-catalyzed epoxidation of vegetable oils present shortcomings such as generation of waste acid and waste water and corrosion of equipment. The M-salen complexes are able to overcome the shortcomings of acid catalyst and have a certain catalytic property which needs to be developed further. The ultrasonic assisting epoxidation of vegetable oils greatly improved the epoxy effect. The immobilization of M-salen complexes can reuse of the catalyst and improve the selectivity.