非催化环己烷自氧化机理的新发展.pptVIP

New development of non-catalytic cyclohexane autoxidation mechanism Contents Importance of non-catalytic cyclohexane autoxidation Features and mechanism of non-catalytic cyclohexane autoxidation New development of the mechanism Discussion and perspective Importance of non-catalytic cyclohexane autoxidation M.M. Sharma and T. Sridhar, Ind. Eng. Chem. Res. 2000, 39, 3958. 6.5x106 (t/a) 90% Conversion <5% Selectivity<78% Nylon products Feature of non-catalytic cyclohexane autoxidation O2 Long initiation time Key role of CyOOH Autocatalytic feature Formation of Acid L. Vereecken, J. Peeters, J. Chem. Phys. 2003, 119, 5159. (▲) ----Cyclohexyl hydroperoxide (CyOOH), (○) ----Cyclohexanone (Q=O), (x) ----Cyclohexanol (CyOH), (+) ---- Acids, Cyclohexane (CyH), 145 oC. 145 oC, CyOOH (▲), CyOH (x), Q=O (○), Acids (+) Feature of non-catalytic cyclohexane autoxidation Q=O show autocatalytic activity compared with CyOH 1% CyOH as initiator 1% Q=O as initiator Traditional mechanism of cyclohexane autoxidation ---Free radical chain mechanism C. A. Tolman, J. D. Druliner, in Activation and Functionalization of Alkanes, Wiley, 1989, 303 Traditional mechanism of cyclohexane autoxidation ---Role of cyclohexanone (perhemiketal) (acids and polymers) Main points CyOOH is key intermediate CyOH and Q=O mainly come from radical termination Formation of perhemiketal from cyclohexanone promote autoxidation By-products mainly come from cyclohexanone Drawbacks Too simple to explain the long-chain radical revolution Did not consider cage-effect and hot-point effect Main points and drawbacks of traditional mechanism Ea and Ka for H-abstraction From different substrates L. Hermans, J. Peeters, ChemPhysChem., 2005, 6, 637. New free radical propagation mechanism L. Hermans, J. Peeters, ChemPhysChem., 2005, 6, 637. 20Kcal.mol-1 40Kcal.mol-1 Need energy Revolution of new formed radicals from H-abstraction New theory about cyclohexanone in promoting the oxidation M.C. Foti, S. Sort