Study On The Preparation Of Mesoporous Molecular Sieve And The Catalytic Performance For The Epoxidation Of Unsaturated Oil

Epoxidized soybean oil (ESO) is an important environment-friendly plasticizer, which has high thermo-stability, water resistance and oil resistance and was used in Polyvinylchloride (PVC). Especially recently, more and more rules ban products containing phthalic acid ester which are harmful to our health. Epoxidized soybean oil obtained from soybean oil (SBO) has great practical value and wide applications in the future only which could be used for the food-packaging bags because it is safety and innocuity. In this paper, the mesoporous molecular sieve as catalyst for synthesis of the ESO was studied.The novel mesoporous materials containing titanium and manganese, Ti-HMS and Mn-HMS were synthesized. It was inveatigated that the metal containing-HMS has a better catalytic behavior for soybean oil epoxidation than MCM-41 mesoporous molecular sieve. HMS (hexagonal mesoporous silica) displays better thermal stability and shorter channels which make reactants access the active centers easier. Ti-HMS and Mn-HMS were characterized by a series of techniques including powder XRD, FTIR, TEM, UV-Vis, TG, ICP-AES and Nitrogen physisorption. It can be concluded that Mn and Ti incorporated into HMS frame and was highly dispersed in the frame of silica. It was found that Mn-HMS has better hydrophobic nature which can slow the water coordination to the metal center and it has fewer–OH which may accelerate the ring opening of the epoxide. So a higher selectivity was observed (>80%) when Mn-HMS (50) was used as catalyst. But, its lower surface area and smaller pore diameter make Mn-HMS has lower conversion.The conditions of epoxidation were investigated. Under reaction conditions: reaction temperature 60 oC, mole ratio of oxidant to SBO 1.5/1, 0.25 g catalyst, reaction time 24 h and 20 mL solvent, the catalyst show better catalytic performance. An optimized Si/Mn ratio exists for catalytic activity, which is about 50/1.The catalytic performances of Mn-HMS and Ti-HMS with different Si/Mn or Si/Ti ratio are related with both metal content in the HMS and the order degree of mesoporous structure.The catalytic reaction mechanism was studied too. The metal plays an important role in the epoxidation.Ti-HMS has been trimethylsilylated by silylating agents: hexametyldisiloxane (HMDS), and which were characterized by FT-IR founding the silylated materials show high hydrophobicity and high catalytic activity in the epoxidation.PVC was plasticited by ESO which substitute for DOP. It was characterized by volatile resistance, migration resistance and thermostability. The result shows that suitable amount of alternative can enhance the thermal stability of PVC products, and the migration resistance of ESO is lower than DOP.