Continuous production of 1,2-propanediol by the selective hydrogenolysis of solvent-free glycerol under mild conditions

Authors

  • Long Huang,

    1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, P.O.Box165, Taiyuan, 030001, PR China
    2. Graduate University of the Chinese Academy of Science, Chinese Academy of Science, Beijing,100039, PR China
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  • Yu-Lei Zhu,

    Corresponding author
    1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, P.O.Box165, Taiyuan, 030001, PR China
    2. Synfuels China Co., Ltd, Taiyuan, 030001, PR China
    • State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, P.O.Box165, Taiyuan, 030001, PR China
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  • Hong-Yan Zheng,

    1. Synfuels China Co., Ltd, Taiyuan, 030001, PR China
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  • Yong-Wang Li,

    1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, P.O.Box165, Taiyuan, 030001, PR China
    2. Synfuels China Co., Ltd, Taiyuan, 030001, PR China
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  • Zhi-Yong Zeng

    1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, P.O.Box165, Taiyuan, 030001, PR China
    2. Graduate University of the Chinese Academy of Science, Chinese Academy of Science, Beijing,100039, PR China
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Abstract

BACKGROUND: The conversion of glycerol to value-added derivatives is now critical, owing to the large surplus of glycerol from biodiesel production. The main objective of this work is to develop a novel process for converting solvent-free glycerol to 1,2-propanediol.

RESULTS: Several catalysts were screened for aqueous-phase hydrogenolysis of glycerol in an autoclave. The most effective catalysts (Ni/Al2O3, Cu/ZnO/Al2O3) were further tested for vapor phase hydrogenolysis in a fixed-bed. Ni/Al2O3 did not prove as effective for the production of 1,2-propanediol because of the high selectivity to CH4 and CO. Over Cu/ZnO/Al2O3, glycerol was mainly converted to the desired 1,2-propanediol and the reaction intermediate acetol. The production of 1,2-propanediol was favoured at higher hydrogen pressure. At 190 °C and 0.64 MPa, near complete conversion of glycerol was achieved with 1,2-propanediol selectivity up to 92%. In addition, a higher concentration (between 43.4% and 0.8%) of acetol was detected and an approximately stoichiometric relationship was found between acetol and 1,2-propanediol.

CONCLUSION: 1,2-propanediol can be produced with high yields via the vapor phase hydrogenolysis of glycerol over Cu/ZnO/Al2O3. Furthermore, the mechanism of 1,2-propanediol formation is suggested to proceed mainly through an acetol route over Cu/ZnO/Al2O3. Copyright © 2008 Society of Chemical Industry

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