Process Development Of Epoxidizing Fatty Acid Methyl Esters With TBHP As Oxygen Source

Epoxy fatty acid methyl esters（EFAMEs）are a kind of environment friendly plasticizers with good thermal stability,compatibility,low volatility and mobility.EFAMEs have been considered as alternative to the hazardous and traditional plasticizers of phthalates dioctyl esters.In this paper,EFAMEs was successfully produced from the waste oil derived FAMEs,with tertiary butyl hydrogen peroxide（TBHP）as oxygen source.Composition of the employed Mo/Bi/γ-Al₂O₃ catalysts and the epoxidation conditions were systematically investigated.Aditionally,Pd/Sn/γ-Al₂O₃catalyzed hydrogenation of the unreacted TBHP,which is explosive at elevated temperature,was also examined after the epoxidation proeces to make a sustainable production of EFAMEs.Experimental results showed that the Mo/Bi molar ratio of Mo/Bi/γ-Al₂O₃ catalyst affected significantly its catalytic performance in the epoxidation of FAMEs.The best activity and selectivity were observed for the catalyst with a Mo/Bi molar ratio of 4.66,with the highest epoxy value（3.98%）and lowest iodine value（5.92 g/100 g）in products.Under the opitimized conditions of the TBHP concentration at 88 wt%,mass ratio of TBHP/FAMEs at 1.5/1,catalyst dosage at 10 wt%of reactants,temperature at 75℃and reaction time at 4 h,the epoxy value of products was as low as 3.98%,and the iodine value was kept below 6 g/100 g,fulfilling the reqirement from the downstream application of plasticizers.Bisides the epoxidation of FAMEs,catalytic hydrogenation of the excessed TBHP over Pd/Sn/γ-Al₂O₃catalysts was also studied in the paper.The Pd/Sn/γ-Al₂O₃catalyst with 18 wt%Sn and Pd contents above 0.15wt%has proven to be the best candidate for the hydrogenationg of TBHP.The strong electronic interaction between Sn and metallic Pd seemed to have played an important role in regulating the activity of Pd/Sn/γ-Al₂O₃catalyst towards the TBHP hydrogenation.Under the optimized reaction conditions of temperature at 65℃,space velocity of TBHP at 2 h^-1,and reaction time at 6h,boht the conversion of TBHP and the selectivity of tert-butyl alcohol were above 95%,contirbuting to a promising route to EFAMES in future.