Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study
Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study
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正交碳化钼上愈创木酚的加氢脱氧：DFT 和微动力学研究
DOI：
10.1039/d1cy01273h
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发表时间：
2022
影响因子：
5
通讯作者：
Agrawal K
中科院分区：
文献类型：
--
作者：
Agrawal K
采用密度泛函理论和微观动力学模拟方法对愈创木酚在（100）β-Mo 2C表面上的加氢脱氧反应进行了模拟。该过程的热化学表明，愈创木酚的脱甲氧基反应形成苯酚将是初始步骤，反应能量为29 kJ mol−1（即吸热），最高活化能为112 kJ mol−1。随后，具有145 kJ mol−1的速率决定活化势垒的苯酚的脱羟基作用将导致苯的形成，其中从愈创木酚转化的总反应能为−91 kJ mol−1（即放热）。发现分子官能团的sp2和sp杂化碳原子在表面上以最小的能垒解离，而吸附分子的氢化需要更高的能量。的微动力学建模，这是考虑到典型的反应条件为500至700 K，和分压比为H2：愈创木酚的1，显示快速形成和积累的苯酚的表面上的温度升高，虽然高温减轻愈创木酚吸附步骤。 基于模拟的程序升温脱附（TPD），愈创木酚的最大转化率可以预期在70%的这种物种的表面覆盖度。
The hydrodeoxygenation of guaiacol is modelled over a (100) β-Mo2C surface using density functional theory and microkinetic simulations. The thermochemistry of the process shows that the demethoxylation of the guaiacol, to form phenol, will be the initial steps, with a reaction energy of 29 kJ mol−1 (i.e. endothermic) and a highest activation barrier of 112 kJ mol−1. Subsequently, the dehydroxylation of the phenol, which has a rate-determining activation barrier of 145 kJ mol−1, will lead to the formation of benzene, with an overall reaction energy for conversion from guaiacol of −91 kJ mol−1 (i.e. exothermic). The sp2 and sp hybridized carbon atoms of the molecular functional groups are found to dissociate on the surface with minimum energy barriers, while the hydrogenation of the adsorbed molecules requires higher energy. The microkinetic modelling, which is performed considering typical reaction conditions of 500 to 700 K, and a partial pressure ratio for H2 : guaiacol of 1, shows quick formation and accumulation of phenol on the surface with increasing temperature, although high temperatures mitigate the guaiacol adsorption step. Based on simulated temperature programmed desorption (TPD), maximum conversion of guaiacol can be expected at 70% surface coverage of this species.