Catalytic Hydrogenation, Hydrodeoxygenation, and Hydrocracking Processes of a Lignin Monomer Model Compound Eugenol over Magnetic Ru/C–Fe2O3 and Mechanistic Reaction Microkinetics

Abstract

Conversion of waste lignocellulosic (LC) biomass, a widely-available low-cost feedstock, into value-added biobased chemicals (and biofuels) has been gaining much attention recently. Therefore, the present lignin valorisation study was aimed at developing magnetically-separable highly-active catalysts for hydrodeoxygenation (HDO), also proposing surface chemical kinetics. Five carbonaceous substrate-deposited Ru were synthesised and tested for the HDO of monomer moiety eugenol. Their annealing temperatures differed, specifically between 300 and 750 °C, while one was not subjected to calcination. Experiments revealed the substantial influence of annealing temperature on the product distribution. Namely, fresh nonannealed nanocomposites were not active for hydrogenolysis. By further pretreatment increase, hydrogenation and, exclusively, the deoxygenation of saturated cyclic species, were enhanced, these being more promoted considering rates and yields than commercial carbon-supported ruthenium. Over 80 mol% of 4-propyl-cylohexanol and propyl-cyclohexane could be formed over the samples, treated at 500 and 600 °C, for 100 and 125 min, respectively, under 275 °C and 5 MPa of reactor hydrogen pressure. Interestingly, a notable 4-propyl-phenol amount was produced upon 750 °C pretreating. The intrinsic microkinetic model, developed previously, was applied to determine relevant turnover parameters. Calculated modelling results indicated a 47- and 10-fold greater demethoxylation and dehydroxylation mechanism ability upon the reheatingpreheating at 600 °C in comparison to industrial (heterogeneous) Ru/C.

Alternate Biobased Route To Produce δ-Decalactone: Elucidating the Role of Solvent and Hydrogen Evolution in Catalytic Transfer Hydrogenation

“…The reaction using formic acid was performed in a batch reactor at 413 K. DDL yield and 6PP conversion obtained after 10 min of the reaction in all the solvent studied are presented in Table . 6PP hydrogenation at the reaction condition was expected to have negligible transport limitations, as observed in the hydrogenation studies of similar molecules in solvent over Ru and other transition metal catalysts. − As evident from the table, the 6PP conversion was observed to be decreasing with the increasing dielectric constant of the solvent. For example, in methanol (ε = 32.7), the 6PP conversion was measured to be 14% (Table , entry 1), which was increased to 99% (Table , entry 5) in cyclohexane (ε = 2.0).…”

Recent Catalytic Approaches for the Production of Cycloalkane Intermediates from Lignin‐Based Aromatic Compounds: A Review

“…The magnetic catalyst (Ru/C‐Fe 2 O 3 ) is reported for conversion of eugenol in hexadecane medium at 275 °C, 50 bat H 2 for 2 h. The Fe 2 O 3 treated at 600 °C (Ru/C−Fe 2 O 3 ‐600) showed high catalytic activity towards the formation of n ‐propylcyclohexane with 80 % yield (Table 3, entry 12). The annealing temperature of Fe 2 O 3 ‐600 composite resulted in high hydrodeoxygenation activity than 300, 500, and 750, which is because of better dispersion of Ru particles on Fe 2 O 3 ‐600 and is associated with high surface area (259 m 2 /g −1 ); the reported surface area of Fe 2 O 3 ‐300, Fe 2 O 3 ‐500, and Fe 2 O 3 ‐750 was 77, 209, 74 m 2 /g −1 [93] …”

Convective Heat Transfer Analysis for Aluminum Oxide (Al2O3)- and Ferro (Fe3O4)-Based Nano-Fluid over a Curved Stretching Sheet

“…Yousefi et al [ 27 ] found the analytical solution for the time-dependent stagnation point flow of a hybrid nano-fluid by considering a moving cylinder. Furthermore, the researchers presenting hybrid nano-fluid models can be seen in [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ].…”