Yuping Li

Synthesis of Methyl Acetate by Dimethyl Ether Carbonylation over Cu/HMOR: Effect of Catalyst Preparation Method

Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mordenite supported copper (Cu/HMOR) catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion‐exchange. The results showed that Cu/HMOR prepared via iron‐exchange method exhibited the highest catalytic activity due to the synergistic effect of active‐site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210 °C, 1.5 MPa, and GSHV of 4883 h−1. The catalysts were characterized by nitrogen absorption, X‐ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion‐exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.

Aqueous‐Phase Hydrodeoxygenation of Biomass Sugar Alcohol into Renewable Alkanes over a Carbon‐Supported Ruthenium with Phosphoric Acid Catalytic System

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.

Promotion of Ni/MCM-41 Catalyst for Hydrogenation of Naphthalene by co-Impregnation with Polyols

The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols (ethylene glycol, glycerol, xylitol, sorbitol and glucose), were investigated by hydro- genation of naphthalene. Compared with the conventional wetness impregnation, addition of moderate polyols into the metal nitrate aqueous solution could enhance interaction with support surface, resulting in formation of very small NiO particle size (<5 nm), high dispersion of the active phase and significant catalytic activity. Particle size of Ni 0 decreased from 36.1 nm to below 5 nm; meanwhile the complete hydrogenation of naphthalene was dependent on the Ni 0 particle size. The hydrogenation activities of the catalysts prepared by co-impregnation with polyols were very high with 100% conversion even at low temperature of 55 °C.

Catalytic conversion of biomass-derived sorbitol to aromatic compounds

ABSTRACT The present wok is focused on a novel method of aromatic compounds production from biomass-derived sorbitol via catalytic processing. Aromatic compounds including substituted benzenes and olefins have been considered to be very promising in the substitution of diminishing fossil fuels since they are component of transportation fuels such as gasoline. The yield of aromatic compounds was found to be affected to a certain extent by reaction parameters and the catalyst. The effects of reaction parameters such as reaction temperature, weight hourly space velocity (WHSV), gas hourly space velocity (GHSV), and hydrogen pressure on the catalytic performance of the catalyst were investigated. The optimum reaction conditions were achieved as follows: 280°C of the temperature, 2.25 hr−1 of WHSV, 2000 hr−1 of GHSV, and 4.0 MPa of pressure. Meanwhile, the Ni/HZSM-5 catalyst modified by MCM-41 was selected to catalyze sorbitol into aromatic compounds. The testing results indicated that the catalyst containing metal centers and acid sites had the maximal activity with 100% of sorbitol conversion. Dehydration and aromatization of sorbitol was induced on the acidic sites of zeolite and its shape selectivity, whereas hydrogenation and cracking was carried out on those mental centers. The carbon distribution of the products was also close to the acidity of the catalyst.

Effect of Ru Particle Size on Hydrogenation/Decarbonylation of Propanoic Acid Over Supported Ru Catalysts in Aqueous Phase

The aqueous-phase hydrogenation of propanoic acid was performed over the Ru/ZrO2 and Ru/Al2O3 catalysts with different Ru loading. Combined with multiple characterization techniques, such as H2-TPR, XRD, CO-FTIR, and DRIFTS of propanoic acid, the effect of Ru loading on the decarbonylation/hydrogenation of propanoic acid was investigated. Although hydrogenation/decarbonylation of carboxylic acids were strongly affected by the nature of supports, the increase of metal loading can cause the larger Ru particles and more bare Ru metal sites, which can facilitate the C–C bond cleavage reaction derived from the decarbonylation of propanoyl species over Ru metal sites.Graphical Abstract

Production of Light Olefins from Biosyngas by Two-stage Catalytic Conversion Process via Dimethyl Ether

NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether (DME) conversion to light olefins (DTO). The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/Al/HZSM-5 and the optimized 2%NiSAPO-34/HZSM-5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2 =-C3 = selectivity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3 syngas when the biosyngas (H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%) with low H/C ratio of 1.0 was used as feed gas.

Pilot-Scale Tests of Direct Dimethyl Ether Synthesis from Biomass-Derived Syngas

Direct conversion of biomass-derived syngas to dimethyl ether(DME) at pilot-scale of 100t/a was carried out in a fixed-bed tubular reactor over Cu/Zn/Al/HZSM-5 catalyst. The bio-syngas was obtained by pyrolysis and gasification of corncob under O2-rich air in fixed-bed reactors. The effects of gasification, synthesis temperature and gas hourly space velocity(GHSV) of bio-syngas on DME synthesis were investigated with the corncob feedrate of 45~50kg/h. The results shows that H2/CO ratio of the obtained bio-syngas was around 1. CO conversion was 75.2% under optimized synthesis temperature of 270�� and GHSV of 1200h -1 . CO conversion and space-time yield of DME were in the range of 82.0~67.7%, 124.3~281.2kg·mcat -3 ·h -1 respectively when GHSV was between 650h -1 and 3000h -1 under 4.3MPa and 260�� . Cu (111) was