钯炭催化木质素模型化合物愈创木酚加氢脱氧制备烷烃

Hydrodeoxygenation of guaiacol as lignin model compound for alkanes preparation with palladium-carbon catalysts

针对木质素催化加氢脱氧制备烃类燃料,以木质素模型化合物愈创木酚催化加氢脱氧制备烷烃为模型反应,研究了活性炭负载Pd、Pt、Ru、Rh金属催化剂,在磷酸溶液中催化愈创木酚加氢脱氧制备烷烃的反应性能。结果表明,Pd/C催化剂显示了较高的催化活性,在催化剂用量0.02g,反应温度225℃,磷酸质量分数0.5%,氢气压力5MPa的条件下反应1h,烃类产物(环己烷和甲基环戊烷)收率可达78%。建立了催化愈创木酚加氢脱氧制备烷烃反应的动力学模型,并得到Pd/C催化愈创木酚转化反应各步的反应速率常数和表观活化能。其中,愈创木酚部分加氢脱氧反应活化能为60.1kJ/mol,含氧产物深度加氢脱氧反应活化能为73.6kJ/mol。研究结果为进一步研究木质素制备烃类燃料提供了参考。

As a model reaction for catalytic hydrodeoxygenation of lignin to produce hydrocarbon fuels, the hydrodeoxygenation of guaiacol was studied over Pd, Pt, Ru and Rh catalysts on carbon. Pd/C was found to be effective for the formation of alkanes including cyclohexane and methyl cyclopentane, the yield of which was over 78% （at temperature 225 ℃, 0.5%mass fraction of H 3 PO 4 , H 2 pressure 5 MPa, 1 h）. Moreover, the serial reaction model of guaiacol conversion was proposed and the kinetics equations were also established. Based on the kinetic experiments, the reaction rate constants and apparent activation energies of each reaction steps in guaiacol hydrodeoxygenation were obtained. The apparent activation energies were 60.1 kJ/mol for partial hydrodeoxygenation to phenols and 73.6 kJ/mol for the following exhaustive hydrodeoxygenation to alkanes. The kinetic models and some general rules on the catalytic hydrodeoxygenation of guaiacol can provide important basic data for efficient utilization of lignin.