title: Preparation of natural alpha-tocopherol from non-alpha-tocopherols.
abstract: Non-alpha-tocopherols are hydroxymethylated and hydrogenated to produce alpha-tocopherol in one pot process by simultaneously reacting with paraformaldehyde and hydrogen in the presence of catalysts of benzenesulfonic acid and 5% Pd/C in an autoclave. Effects of various operation conditions have been studied. The preferable reaction conditions are: temperature 180 degrees C to 200 degrees C, pressure 5.0 MPa, acid concentration 0.5 g/100 ml ethanol, mass ratio of Pd/C to tocopherols 7.1 g/100 g, and reaction time 5.0 h. A product with alpha-tocopherol content of 80% was obtained by using a raw material with a total tocopherols content of 80.54%. The conversion of non-alpha-tocopherols is almost 100%, and the mole yield of alpha-tocopherol is more than 90%.
authors.affiliation: National Laboratory of Secondary Resources Chemical Engineering, Zhejiang University, Hangzhou 310027, China. ceywyang@zju.edu.cn
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Yang
authors.forename: Guang-Dong
authors.initials: GD
authors.lastname: Wen
authors.forename: Cai-Juan
authors.initials: CJ
authors.lastname: Wu
authors.forename: Qi-Long
authors.initials: QL
authors.lastname: Ren
authors.forename: Ping-Dong
authors.initials: PD
authors.lastname: Wu
mesh_terms: D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011312:Pressure; D013696:Temperature; D024505:Tocopherols / Q000737:chemistry; D024502:alpha-Tocopherol / Q000138:chemical synthesis* / Q000302:isolation & purification*
chemical_list: D006859:Hydrogen; D024502:alpha-Tocopherol; D024505:Tocopherols