4 research outputs found
DFT study on gas-phase hydrodeoxygenation of guaiacol by various reaction schemes
<p>Guaiacol is an important phenolic component present in pyrolytic bio-oils; and in this work its hydrodeoxygenation (HDO) by various reaction schemes has been considered within the framework of density functional theory. In this computational study, primarily three reaction schemes for the HDO of guaiacol are considered. In the first reaction scheme (<b>RS 1</b>), guaiacol undergoes hydrogenolysis at O–CH<sub>3</sub> bond site of methoxy group to produce catechol and methane followed by HDO of catechol forming phenol and water, followed by HDO of phenol producing benzene and water and finally benzene leading to cyclohexane formation. In the second reaction scheme (<b>RS 2</b>), guaiacol undergoes hydrogenolysis at C<sub>aromatic</sub>–O bond of methoxy group producing phenol and methanol followed by hydrotreatment of phenol to form cyclohexane along with same intermediates as in the first reaction scheme. In the third reaction scheme (<b>RS 3</b>), HDO of guaiacol compound at C<sub>aromatic</sub>–OH sigma bond produces anisole and water; and then anisole follows two secondary pathways to produce cyclohexane. In this computational study, the transition state optimisations, vibrational frequency and IRC calculations are carried out by B3LYP functional with 6-311+g(d,p) basis set using Gaussian 09 and Gauss View 5 software package.</p
Electronic Supplementary Material for the manuscript entitled "Platinum Catalyzed Hydrodeoxygenation of Guaiacol in Illumination of Cresol Production: A DFT Study". from Platinum catalyzed hydrodeoxygenation of guaiacol in illumination of cresol production: a DFT study
Arrhenius equations and optimized molecular structures of all elementary reaction steps
Computational Study on Ring Saturation of 2‑Hydroxybenzaldehyde Using Density Functional Theory
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+gÂ(d,p) level of theory. Furthermore, a single
point energy calculation is performed at each structure at the M06-2X/6-311+gÂ(3df,2p)//B3LYP/6-311+gÂ(d,p)
level of theory to accurately predict the energy requirements. According
to bond dissociation energy calculations, the dehydrogenation of formyl
group of 2-hydroxybenzaldehyde is the least energy demanding bond
cleavage. The production of cyclohexane has a lower energy of activation
than the production of cyclohexanone
Quantum chemical study on gas phase decomposition of ferulic acid
<p>Ferulic acid, representing phenolic fraction of bio-oil, is considered to be a model compound in this study for its decomposition into various end products such as ethylbenzene, eugenol, <i>cis</i>-isoeugenol, vanillin, 4-ethylguaiacol, guaiacol, and acetovanillone using density functional theory approach. Results of bond dissociation energies indicate that cleavage of methyl group from ferulic acid is the lowest energy-demanding bond scission amongst all 14 bond cleavages. Primary end product by decomposition of ferulic acid is found to be ethylbenzene and its production occurs through the formation of intermediate products such as 4-hydroxycinnamic acid, cinnamic acid and styrene. Demethoxylation of ferulic acid gives rise to the production of 4-hydroxycinnamic acid which further undergoes the formation of cinnamic acid by dehydroxylation reaction route. The formation of cinnamic acid in this study is carried out using three reaction schemes 1–3 and its further reduction to ethylbenzene is performed using two reaction possibilities. Finally, favourable pathway is found to be decarboxylation of cinnamic acid to produce vinylbenzene followed by the production of ethylbenzene using hydrogenation of C=C chain double bond. Furthermore, thermochemistry of each reaction scheme is performed at atmospheric pressure and at a wide range of temperature of 598–898 K.</p