Vanillin hydrodeoxygenation kinetics on takovite derived NiAlOx mixed oxides

• Published in: Catalysis today Vol. 394-396; pp. 103 - 109
• Main Authors: Vázquez-Fuentes, Luis F., Cortés-Jácome, María A., López-Salinas, E., Sánchez-Valente, J., Toledo-Antonio, José A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: Decarbonylation; Dehydration; Demethoxylation; Hydrodeoxygenation; Hydrogenation; NiAlOx mixed oxides; Vanillin; NiAlOx mixed oxides; DCO; HDO; Hydrodeoxygenation; Decarbonylation; Vanillin; Dehydration; Hydrogenation; Demethoxylation
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2021.11.002

Vanillin, a representative moiety of lignin, having three different oxygenated groups, was used as a model molecule on catalytic hydrodeoxygenation (HDO). The transformation of vanillin was carried out at in a batch reactor at 413–573 K, 1.2 MPa of H2 and using a takovite-derived, reduced NiAlOx mixed oxide. The concentration of the reaction products, as well as vanillin conversion, was measured by gas-chromatography. After identifying the products, a reaction network scheme was proposed in order to calculate the reaction rates by assuming a pseudo-first order. Then, from an ordinary differential equations system for each species of each reaction network, the concentration value evolution was calculated using Runge Kutta- Butcher 5th order method. For each concentration experimental data in the reaction mixture a minimum-square adjustment with Levenberg-Marquardt minimization was used. The experimental data were fitted by a FORTRAN (“mIKC”) code, which numerically solved the differential equations system until obtaining the ones in this work. A very good fitting between experimental data and the calculated ones using the proposed reaction rate equations validated the reaction scheme. Reaction temperature plays a crucial role when aiming to obtain fully deoxygenated products, e.g. hydrocarbons like cyclohexane and methyl cyclohexane, 553 K being the ideal one. [Display omitted] •A reaction network for vanillin HDO on a reduced NiAlOx catalyst was proposed.•Kinetic constants were determined using pseudo-first order reaction rate equations.•Aromatic hydrogenation and demethoxylation occur on the same metallic sites.•Vanillin can be converted into completely deoxygenated hydrocarbons at 553 K.