木质素降解模型化合物愈创木酚及苯酚原位加氢制备环己醇

以Raney Ni为催化剂,研究了甲醇水相重整制氢与木质素降解模型化合物愈创木酚／苯酚加氢的耦合反应.考察了反应前冷压、反应温度、反应时间、物料配比等条件对木质素降解模型化合物原位加氢反应性能的影响,并对影响机制进行了讨论.结果表明,在反应温度为220 ℃、反应前冷压0 MPa(表压)、物料比水／甲醇／模型化合物为20∶5∶0.8的条件下,反应7 h后愈创木酚转化率与环己醇选择性分别达99.00％和93.74％,反应12 h后苯酚的转化率与环己醇选择性分别达90.50％和99.29％.采用原位加氢反应,木质素降解的酚类模型化合物转化率和选择性明显优于外部供氢反应的转化率和选择性,同时,避免了外部供氢反应存在的氢气制备、储存、传输及加氢条件苛刻等问题,为木质素解聚产物制备化工品提供了新思路与实验基础.

In-situ hydrogenation of lignin depolymerization model compounds to cyclohexanol

The integrated process of aqueous phase reforming of methanol for hydrogen and hydrogenation of phenol and guaiacol, two lignin model compounds, was conducted with Raney Ni catalyst in this work. The effects of pressure, temperature, reaction time and mixture ratio of reactants on the performance of in-situ hydrogenation of lignin depolymerization model compounds were investigated. The mechanism was also discussed. Results showed that the guaiacol conversion and cyclohexanol selectivity reached 99.00% and 93.74% with time-on-stream of 7 h, while the phenol conversion and cyclohexanol selectivity were 90.50% and 99.29% with time-on-stream of 12 h under the optimal conditions of 220 ℃, initial pressure of 0 MPa(gauge pressure) and mole ratio of water/methanol/feedstock=20/5/0.8. The in-situ hydrogenation of phenolic compounds was also proved to be superior to the hydrogenation system of phenols with external hydrogen supply. This work provides a new alternative for production of chemicals from the depolymerization products of lignin.