Huanling Song

Catalytic conversion of cellulose to chemicals in ionic liquid

A simple and effective route for the production of 5-hydroxymethyl furfural (HMF) and furfural from microcrystalline cellulose (MCC) has been developed. CoSO(4) in an ionic liquid, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1), was found to be an efficient catalyst for the hydrolysis of cellulose at 150°C, which led to 84% conversion of MCC after 300min reaction time. In the presence of a catalytic amount of CoSO(4), the yields of HMF and furfural were up to 24% and 17%, respectively; a small amount of levulinic acid (LA) and reducing sugars (8% and 4%, respectively) were also generated. Dimers of furan compounds were detected as the main by-products through HPLC-MS, and with the help of mass spectrometric analysis, the components of gas products were methane, ethane, CO, CO(2,) and H(2). A mechanism for the CoSO(4)-IL-1 hydrolysis system was proposed and IL-1 was recycled for the first time, which exhibited favorable catalytic activity over five repeated runs. This catalytic system may be valuable to facilitate energy-efficient and cost-effective conversion of biomass into biofuels and platform chemicals.

Hydrolysis of cellulose in SO3H-functionalized ionic liquids

Influence of acidity and structure of ionic liquids on microcrystalline cellulose (MCC) hydrolysis was investigated. MnCl₂-containing ionic liquids (ILs) were efficient catalysts and achieved MCC conversion rates of 91.2% and selectivities for 5-hydroxymethyl furfural (HMF), furfural and levulinic acid (LA) of 45.7%, 26.2% and 10.5%, respectively. X-ray diffractometry indicated that catalytic hydrolysis of MCC in ionic liquids resulted in the changes to MCC crystallinity and transformation of cellulose I into cellulose II. SO₃H-functionalized ionic liquids showed higher activities than non-functionalized ILs. The simplicity of the chemical transformation of cellulose provides a new approach for the use this polymer as raw material for renewable energy and chemical industries.

Methanation of Carbon Dioxide over a Highly Dispersed Ni/La2O3 Catalyst

The methanation of carbon dioxide on a Ni/La2O3 catalyst containing 10 wt% Ni prepared by the impregnation method was studied. The space-time yield of methane was 3000 g/(kg·h) at conditions of 350 °C, GHSV of 30000 h−1, 1.5 MPa pressure, and H2/CO2 molar ratio of 4. The selectivity for methane was 100% with different CO2 conversions. Combined with X-ray diffraction and H2 temperature-programmed reduction analyses, this suggested that the reaction mechanism on Ni/La2O3 may be different from that on Ni/γ-Al2O3. The formation of lanthanum oxycarbonate (La2O2CO3) can play an important role in the activation of CO2.

Dehydration of fructose into 5-hydroxymethylfurfural in acidic ionic liquids

A simple and effective process for the dehydration of fructose into 5-hydroxymethylfurfural (HMF) using ionic liquid 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1) as the catalyst was developed. High fructose conversion of 100% with HMF yield of 94.6% was obtained at 120 °C for 180 min reaction time in water-4-methyl-2-pentanone (MIBK) biphase system. Generally, the increase of water content had a negative effect on the reaction, the HMF selectivity decreased as the excessive elevation of temperature and prolonging of time, which suggested the decomposition of HMF. The ionic liquid IL-1 could be recycled and exhibited constant activity for six successful runs. This paper provided a new strategy for HMF production from fructose.

Characterization and performance of Cu/ZnO/Al2O3 catalysts prepared via decomposition of M(Cu, Zn)-ammonia complexes under sub-atmospheric pressure for methanol synthesis from H2 and CO2

Abstract Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu, Zn)-ammonia complexes (DMAC) at various temperatures. The catalysts were characterized in detail, including X-ray diffraction, N2 adsorption-desorption, N2O chemisorption, temperature-programmed reduction and evolved gas analyses. The influences of DMAC temperature, reaction temperature and specific Cu surface area on catalytic performance are investigated. It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts. The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat · h); T = 513 K, p = 3 MPa, SV = 12000 h−1).

Preparation of a Cu–Ce–O Catalyst by Urea Combustion for Removing CO from Hydrogen

Abstract A urea combustion method was used for the preparation of the Cu–Ce–O catalyst without the need for a binder or additional calcination steps. The catalytic performance of the catalyst for preferential oxidation of CO was investigated under dry and humid feed gas conditions, and the catalyst was also examined for CO removal at the operating temperature of the PEMFC anode. A 99.3% CO conversion and 75% selectivity for CO 2 could be achieved at 130°C in the presence of H 2 O and CO 2 . The results of XRD and SEM characterizations indicated that copper oxides were highly dispersed on the catalyst and formed nanoparticles.

Preparation of Cu/ZnO/Al2O3 Catalyst for CO2 Hydrogenation to Methanol by CO2 Assisted Aging

Abstract A Cu/ZnO/Al 2 O 3 catalyst prepared by adding CO 2 during the aging step was used for methanol synthesis from CO 2 and H 2 . The catalysts were characterized by N 2 adsorption-desorption, X-ray diffraction, field emission scanning electron microscope, temperature-programmed decomposition, and temperature-programmed reduction. The precursor from the modified method with added CO 2 had malachite and hydrotalcite-like phases and was more stable than that of the sample without added CO 2 . After calcination, the modified catalyst had a higher surface area, larger pore volume, and smaller particle size. The modified catalyst gave a higher activity for methanol synthesis from CO 2 hydrogenation in the reaction temperature range of 200-260 °C.

Preparation, characterization and catalytic performance study of La-TS-1 catalysts

Lanthanum (La) was substituted into a titanium silicalite 1 (TS-1) framework via two different synthetic approaches, i.e., in situ hydrothermal synthesis and ultrasonic immersing methods. La inhibited Ti to enter into the TS-1 framework during in situ hydrothermal synthesis, and thus Ti erosion gave rise to poor catalytic activity for butadiene (BD) epoxidation. While catalysts prepared by an ultrasonic immersing method were testified as fine ones by mutually complementary characterization and catalytic tests. Extraframework-La and Si–OH caused by framework-La enhanced the acidity of TS-1. Adequate intensity of acidity aroused from 8 wt% La modified had activated H2O2 for BD epoxidation rather than promoting the solvolysis reactions of the epoxide. Moreover, interactions between framework-La and the Ti active center via O weakened the [Ti–O] bond, which facilitated active intermediate formation. As a result, H2O2 conversion and utilization, along with vinyloxirane (VO) yield and TON were highly promoted with appropriate content of La modified.

Effect of metals on titanium silicalite TS-1 for butadiene epoxidation

Abstract The titanium silicalite-1 (TS-1) modified by various metals (M-TS-1; M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, La, 1% metals loading) catalysts were employed to catalyze butadiene epoxidation. The metals influenced the TS-1 activity in various ways. V, Cr, and Mn caused H2O2 decomposition. Although the H2O2 conversion was high, its utilization was relatively low. The introduction of Fe, Co, Ni, and La into TS-1 promoted the vinyloxirane (VO) yield and H2O2 utilization to some extent. Cu and Zn modification inhibited the H2O2conversion to VO, resulting in both low H2O2 utilization and conversion. We studied the influence of Cd on TS-1 and found that H2O2was almost totally converted to VO over the Cd-TS-1 catalyst, and the turnover number of VO reached 1197. Powder X-ray diffraction, N2 adsorption and desorption, X-ray photoelectron spectroscopy, and Fourier transformed infrared spectra were employed to characterize the specific metal role at the Ti site in the M-TS-1 catalysts. The TS-1 remained as MFI structure with doped metals. The added metals effectively changed the electron environment of the Ti active site. However, no universal trend in behavior was observed for these metals.

Effective and stable CeO2-W-Mn/SiO2 catalyst for methane oxidation to ethylene and ethane

Abstract CeO 2 -W-Mn/SiO 2 catalyst is found to be effective for the oxidative coupling of methane (OCM); ca. 30of C 2 + and 22of C 2 H 4 yields have been obtained in single pass at 800 °C. During the 500 h continuous reaction, no significant decrease of activity and selectivity is observed.