Synthesis Of Epoxidized Plasticizer Catalyzed By Molybdenum Polyoxometalate

Epoxidized soybean oil methyl ester and epoxidized soybean oil are safe,non-toxic high-quality environmentally friendly plasticizers that can replace traditional phthalate plasticizers in plastic packaging for food and medical supplies.Therefore,it has important application prospects.Acid catalysis is a traditional synthetic method for epoxidized plasticizers,but there are problems such as environmental pollution and corrosion equipment.Therefore,it is particularly important to find a green and efficient epoxidized plasticizer synthesis method.Molybdenum polyoxometallate has the advantages of easy preparation,chemical stability,and environmental friendliness,and is widely used to catalyze organic reactions such as olefin epoxidation and double hydroxylation.It has important research significance to synthesize epoxidized plasticizer using molybdenum polyoxometallate as catalysts.Molybdenum polyoxometallates were synthesized and used to catalyze the synthesis of epoxidized plasticizers in this paper.Tetraalkylammonium molybdate,imidazole molybdate and pyridine molybdate were prepared and characterized by elemental analysis,¹H NMR,FT-IR and crystal structure.The structure of the synthesized compounds was consistent with the target product.The epoxidation of soybean oil methyl ester was synthesized under the the catalysis of tetraethylammonium molybdate.The effects of reaction temperature,reaction time,catalyst and hydrogen peroxide on the epoxidation reaction were discussed.The results showed that the reaction temperature,the amount of catalyst and hydrogen peroxide have a significant effect on the reaction.Epoxidized soybean oil methyl ester with an acid value of 0.58 mg/g and an epoxy value of 3.73%was obtained under the optimal conditions.The tetraethylammonium molybdate was used as catalyst in the preparation of epoxidized soybean oil,and the effects of the above four factors on the epoxidation reaction were investigated.The results showed that the amount of catalyst and hydrogen peroxide are the main factors affecting the epoxidation of soybean oil.Epoxidized soybean oil with the acid value of0.49 mg/g and the epoxy value of 5.62%was obtained under optimization condition.The catalytic performance of 6 kinds of different molybdenum polyoxometalate catalysts on the epoxidation of soybean oil methyl ester was compared.It can be found that the larger the cationic group,the larger the steric hindrance and the worse the catalytic activity.The mechanism of epoxidation over molybdenum polyoxometallate was further investigated.It is believed that the[MoO（O₂）₂]^2-active intermediate formed by the interaction of Mo₈O₂₆^4-and H₂O₂ play the key role in the catalytic process.