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Herein, WO x -decorated Ir/SiO 2 (W/Ir = 0.06) and HZSM-5 were coupled to selectively convert microcrystalline cellulose (MCC) into C 6 alkanes. A 92.8% yield of liquid alkanes including an 85.3% yield of C 6 alkanes was produced at 210 °C. Cellulose hydrolysis, glucose hydrogenation and sorbitol hydrodeoxygenation were integrated to produce alkanes via a sorbitol route. Ir-WO x /SiO 2 showed high performance for hydrogenation and hydrodeoxygenation reactions after hydrolysis catalyzed by HZSM-5. The intimate contact between WO x and Ir enhanced the synergistic interaction through the electron transfer from Ir to WO x . The interaction strengthened the reduction capability of Ir for hydrogenations, as well as improved the adsorption and activation of C-O bonds on reduced WO x for deoxygenations. The monotungstate WO x species provided moderate Lewis acids to cooperate with Ir to accelerate hydrodeoxygenations with alleviated retro-aldol condensation to yield more C 6 alkanes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Sorbitol, as a C6 sugar related compound derived from cellulose, is regarded as a promising biomass‐derived substrate and has characteristically higher oxygen content than in fossil‐based resources. In this work, ruthenium–molybdenum carbon catalysts prepared by different impregnation processes were employed and extensively studied in a trickle‐bed reactor for sorbitol hydrodeoxygenation (HDO). Interestingly, these catalysts afforded remarkably different HDO performance. Ruthenium–molybdenum catalysts prepared by ultrasonic treatment and calcination obtained high HDO performance in sorbitol conversion with 79.8 % carbon yield of C5/C6 alkanes (pentane and hexane), almost twice that of ruthenium–molybdenum catalysts prepared without using a calcination processes. Therefore, a series of characterization studies (N2‐adsorption, XRD, HRTEM, XPS, H2‐TPR, CO‐TPD, NH3‐TPD, Py‐IR spectra, etc.) were performed over relevant catalysts to study the catalytic mechanism. The results suggest that prior calcination offers a better chance for the proximity between Ru and Mo precursors to produce the bimetallic catalytic structure Ru–MoOx, which produces high HDO performance. Sweet catalysis: Ru–MoOx/C catalysts from different impregnation processes were carefully studied and extensively employed for sorbitol conversion to C5/C6 alkanes in trickle‐bed reactor. The results suggest that prior calcination offers a better chance for the proximity between Ru and Mo precursors to produce the bimetallic catalytic structure Ru–MoOx, which produces high HDO performance towards biofuels synthesis. [ABSTRACT FROM AUTHOR]

Recently, we demonstrated the catalytic conversion of biomass hydrolysate and real biomass into renewable alkanes over a Ru/C catalyst with aqueous phosphoric acid (Ru/C+H3PO4) and we obtained a high yield of C5/C6 alkanes. In this study, the mechanism of sorbitol hydrodeoxygenation (HDO) into alkanes over the Ru/C+H3PO4 catalytic system was investigated by using a trickle-bed reactor. A high HDO performance was detected with a large amount of long-chain alkanes in the products. Subsequently, pre- and postcharacterization studies (N2 adsorption, XRD, X-ray photoelectron spectroscopy, TEM, NH3 temperature-programmed desorption, H2 temperature-programmed reduction, FTIR spectroscopy) were performed on the relevant catalysts to study the change of the catalytic active sites. Moreover, mineral acid experiments were performed to study the influence of phosphoric acid on the HDO performance. [ABSTRACT FROM AUTHOR]

Abstract: For the aqueous-phase hydrodeoxygenation (APHDO) of carboxylic acids over the Ru/C, Ru/ZrO2 and Ru/Al2O3 catalysts, the Cnation and C–C bond cleavage reactions were studied by collecting reaction kinetics data and the measures of DRIFTS. The C–C bond cleavage was improved at high temperature and with high metal loadings. The acidic supports in combination with Ru metal can favor the Cnation of carboxyl. The C–C bond cleavage derived from the decarbonylation of acyl on the catalyst was studied by the measures of DRIFTS. The APHDO and DRIFTS results demonstrated that the C–C bond cleavage was favored in the order of Ru/C>Ru/ZrO2 >Ru/Al2O3. The catalysts were characterized by multiple methods (H2-TPR, NH3-TPD, CO-FTIR and DRIFTS of propanoic acid). It is concluded that the effect of support on the reaction routes may be attributed to these factors of catalysts, i.e., surface acidity, metal–support interaction and electronic state of Ru species. [Copyright &y& Elsevier]

The Cover shows the catalytic conversion of biomass hydrolysate into renewable alkanes over a Ru/C catalyst with aqueous phosphoric acid (Ru/C+H3PO4), in which a high yield of C5/C6 alkanes was obtained.In their Full Paper, Y. Weng et al. investigated the mechanism of the sorbitol hydrodeoxygenation (HDO) reaction into alkanes over a Ru/C+H3PO4 catalyst by using a trickle‐bed reactor. Higher HDO performance might be a result of the bifunctional role of the catalytic system. These findings suggest that the downstream process of biomass hydrolysis could be directly conducted in acid aqueous phase at low reaction temperature, reducing the amount of acid waste. [ABSTRACT FROM AUTHOR]

In this work, a dual-bed aqueous catalysis system with Ru/C as catalyst was proposed for the liquid alkane (pentane/hexane: C5/C6) production from acid biomass hydrolysate. The low temperature (413 K) hydrogenation of biomass-derived carbohydrates into polyols was carried out in the first fixed-bed. The high temperature (523 K) hydrodeoxygenation (HDO) of polyols into alkanes was carried out in the down-stream bed. To screen the optimal reaction conditions, glucose and sorbitol were chosen for model tests. Whereby, reactor types, solution pH value, mineral acid, reaction temperature, pressure and sorbitol concentrations were studied. A maximum C5/C6 alkane yield of 61.9% was achieved from 20 wt% sorbitol solution (pH = 1.5) under 523 K and 4 MPa H 2 pressure in the fixed-bed reactor. For cassava and corncob hydrolysate, C5/C6 alkane yield of 38.8% and 44.1% were obtained, respectively. [ABSTRACT FROM AUTHOR]

Direct HDO process for difurfurylidene acetone dimer (F 2 A) conversion to liquid alkanes (C 8 C 14 ) at 260 °C in a batch reactor was investigated over different material supported 1 wt%Pt catalysts, including SAPO-11, HZSM-5, SiO 2 Al 2 O 3 , MCM-22, and home-made SiO 2 ZrO 2 . C 8 C 14 alkanes of 55.8% was obtained over the optimized 1 wt%Pt/SiO 2 ZrO 2 due to its proper pore size of 9.0 nm and moderate acidic centers, together with more than 10% carbon yield of the oxygenated hydrocarbons, including C 11 C 13 chain alcohols & ketones and the hydrogenated F 2 A dimers with furan ring (H-F 2 A dimers). To improve the liquid alkane yield, a two-step process for F 2 A conversion was also investigated, which included low-temperature hydrogenation at 50 °C over Raney Ni catalyst in a batch reactor and the subsequent high-temperature hydrodeoxygenation (HDO) at 280 °C over 1 wt%Pt/SiO 2 ZrO 2 in a fixed-bed reactor. The selectivity of 1,5-di(tetrahydro-2-furanyl)-3-pentanol (II-c) was the highest of 83.0% among the hydrogenated intermediates of H-F 2 A dimers due to the protonation effect of methanol as the solvent and the hydrogenation of C C bonds by Ni active centers. In the same time, the high content of this saturated alcohol H-dimer of II-C increased the solubility and stability of the intermediates in methanol solvent. High carbon yield of C 8 C 14 alkanes of 82.9%(mol) was obtained after oxygen atom removal from H-F 2 A dimers via. the second-step HDO reaction. Long time operation showed the stability of 1 wt%Pt/SiO 2 ZrO 2 as HDO catalyst, deduced from the steady phase structure, acidity of SiO 2 ZrO 2 support and Pt active centers by catalyst characterization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solid base NaOH/CT-4 is effective in condensation of furfural and levulinic acid. • The synergistic effect of amino and NaOH gives a high C15 yield. • Catalytic kinetic analysis of the condensation over NaOH/CT-4 was conducted. • Condensed products can be converted into jet fuel range alkanes by HDO. In this paper, jet fuel range alkanes were produced by aldol condensation of furfural and levulinic acid over modified chitosan catalyst and subsequent hydrodeoxygenation. NaOH modified chitosan was developed and used as a solid catalyst in the aldol condensation of furfural and levulinic acid to produce long carbon chain compounds. At room temperature, the total yield of condensation products reached 94.4% over NaOH/CT-4 catalyst. The amine of chitosan plays an important role in the aldol condensation, which reacted with the aldehyde group of the furfural, producing an intermediate Schiff base and promoting the formation of condensation products. This new route avoided the occurrence of side reactions caused by NaOH. Therefore, the yield of the products was greatly increased. Moreover, kinetic analysis of the condensation reaction and the test of catalyst repeatability were also conducted with NaOH/CT-4. The condensation products were further converted to long-chain branched alkanes by hydrodeoxygenation over the 5 wt% Pd/NbOPO 4 catalyst. As a potential application, these alkanes could be mixed with and used as the components of jet fuels. [ABSTRACT FROM AUTHOR]