Pino Natalia, López Diana, Espinal Juan F
Química de Recursos Energéticos y Medio Ambiente, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
J Mol Model. 2019 Jan 5;25(1):26. doi: 10.1007/s00894-018-3908-0.
Furfural is a valuable oxygenated compound derived from the thermal decomposition of biomass, and is one of the major problems of bio-oil upgrading. Due to its high reactivity, this compound requires further upgrading to more stable products such as furfuryl alcohol, 2-methylfuran (MF), furan, 2-methyltetrahydrofuran, and tetrahydrofuran. The thermochemical data and kinetic analysis of the reactions involved in the conversion of furfural were investigated by molecular modeling to guide experimental investigations in the process of designing efficient catalysts that allows the control of the reaction pathways in specific directions, towards the production of fuel precursors or chemicals. All calculations for reactants, intermediates, and products were performed using the long range corrected functional WB97XD, with the basis set 6-311+g(d,p), under the density functional theory framework. Thermochemistry results suggest that furfural hydrogenation to form furfuryl alcohol is spontaneous up to a temperature of 523 K, but beyond this temperature the reaction becomes a nonspontaneous process. By contrast, the decarbonylation of furfural was thermodynamically favored at temperatures greater than 523 K. Therefore, furan is a thermodynamically favored product, while furfuryl alcohol is kinetically preferred. Once furfuryl alcohol is formed, the hydrogenolysis path to produce methylfuran is favored kinetically and thermodynamically, compared to the ring-hydrogenation towards tetrahydrofurfuryl alcohol. Gas phase thermodynamic properties and rate constants of the reactions involved in the conversion of furfural were calculated and compared against existing experimental data. This study provides the basis for further vapor phase catalytic studies required for upgrading of furans/furfurals to value-added chemicals. Graphical abstract Furan is a thermodynamically favored product, while furfuryl alcohol is kinetically preferred.
糠醛是一种由生物质热解产生的有价值的含氧化合物，也是生物油升级的主要问题之一。由于其高反应活性，该化合物需要进一步升级为更稳定的产物，如糠醇、2-甲基呋喃（MF）、呋喃、2-甲基四氢呋喃和四氢呋喃。通过分子模拟研究了糠醛转化过程中所涉及反应的热化学数据和动力学分析，以指导在设计高效催化剂过程中的实验研究，该催化剂能够控制反应路径朝着特定方向进行，以生产燃料前驱体或化学品。在密度泛函理论框架下，使用长程校正泛函WB97XD和基组�6-311+g(d,p)对反应物、中间体和产物进行了所有计算。热化学结果表明，糠醛加氢生成糠醇在温度高达523K时是自发的，但超过该温度后反应变为非自发过程。相比之下，糠醛的脱羰反应在温度高于523K时在热力学上更有利。因此，呋喃是热力学上更有利的产物，而糠醇在动力学上更受青睐。一旦形成糠醇，与向四氢糠醇的环加氢相比，生成甲基呋喃的氢解路径在动力学和热力学上都更有利。计算了糠醛转化过程中所涉及反应的气相热力学性质和速率常数，并与现有的实验数据进行了比较。本研究为将呋喃/糠醛升级为增值化学品所需的进一步气相催化研究提供了基础。图形摘要：呋喃是热力学上更有利的产物，而糠醇在动力学上更受青睐。
