Computational Study on Ring Saturation of 2-HydroxybenzaldehydeUsing Density Functional Theory

摘要

Bio-oil produced from pyrolysis of lignocellulosic biomass consists of several hundreds of oxygenated compounds resulting in a very low quality with poor characteristics of low stability, low pH, low stability, low heating value, high viscosity, and so on. Therefore, to use bio-oil as fuel for vehicles, it needs to be upgraded using a promising channel. On the other hand, raw bio-oil can also be a good source of many specialty chemicals, e.g., 5-HMF, levulinic acid, cyclohexanone, phenol, etc. In this study, 2-hydroxybenzaldehyde, a bio-oil component that represents the phenolic fraction of bio-oil, is considered as a model compound and its ring saturation is carried out to produce cyclohexane and cyclohexanone along with various other intermediate products using density functional theory. The geometry optimization, vibrational frequency, and intrinsic reaction coordinate calculations are carried out at the B3LYP/6-311+g(d,p) level of theory. Furthermore, a single point energy calculation is performed at each structure at the M06-2X/6-311+g(3df,2p)//B3LYP/6-311+g(d,p) level of theory to accurately predict the energy requirements. Accordingto bond dissociation energy calculations, the dehydrogenation of formylgroup of 2-hydroxybenzaldehyde is the least energy demanding bondcleavage. The production of cyclohexane has a lower energy of activationthan the production of cyclohexanone.