Yunlai Su

Sulfonated hierarchical H-USY zeolite for efficient hydrolysis of hemicellulose/cellulose.

Sulfonated hierarchical H-USY zeolite was prepared and characterized by X-ray diffraction, N2 physisorption, Fourier transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, temperature-programmed desorption of ammonia, and acid-base titration. It was proved that sulfonic group was successfully anchored onto the hierarchical H-USY zeolite. The acidity of the hierarchical H-USY was remarkably improved. Sulfonated hierarchical H-USY zeolite was efficient for the hydrolysis of hemicellulose and cellulose. The yield of TRS for hydrolysis of hemicellulose reached 78.0% at 140 °C for 9h. For hydrolysis of α-cellulose, 60.8% conversion with 22.4% yield of glucose was obtained. Even for microcrystalline cellulose, 43.7% conversion with 15.1% yield of glucose can be obtained. These results are much higher than those obtained over hierarchical H-USY zeolite, indicating that both the acidity and the pore structure determine the activity of zeolite as catalyst in the hydrolysis of biomass.

Conversion of syngas to higher alcohols over Cu-Fe-Zr catalysts induced by ethanol

Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method, it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol, the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.

Fluoride-free and low concentration template synthesis of hierarchical Sn-Beta zeolites: efficient catalysts for conversion of glucose to alkyl lactate

Hierarchical Sn-Beta zeolite was prepared through a hydrothermal postsynthesis method, which employed no fluoride and only a small amount of tetraethyl ammonium hydroxide (TEAOH). The dual roles of TEAOH as a base and as a structure directing agent were discussed in detail, which were significantly affected by its concentration. At a TEAOH concentration of 0.2–0.4 mol L−1, hierarchical Sn-Beta zeolites with the most probable mesopore diameter of 7.8 nm were achieved. Other physicochemical properties of the hierarchical Sn-Beta including the content and state of Sn and the acidity were also characterized. The hierarchical Sn-Beta zeolite gave a higher yield of methyl lactate (58%) than the microporous Sn-Beta zeolite synthesized in fluoride medium (47%) due to the promoting effect of the hierarchical porosity on the conversion of glucose in methanol, which is an important and challenging process of a biorefinery. The hierarchical Sn-Beta zeolite is stable and can be recycled and reused five times without significant loss of activity and selectivity.

Preparation and characterization of ultrafine Fe-Cu-based catalysts for CO hydrogenation

Abstract The ultrafine particles of a new style Fe-Cu-based catalysts for CO hydrogenation were prepared by impregnating the organic sol of Fe(OH) 3 and Cu(OH) 2 onto the activated Al 2 O 3 , in which the organic sol of Fe(OH) 3 and Cu(OH) 2 were prepared in the microemulsion of dodecylbenzenesulfonic acid sodium(S)/ n -butanol(A)/toluene(O)/water with V (A)/V (O) = 0.25 and W (A)/W (S) = 1.50. This catalyst was characterized by particle size analysis, XRD and TG. The results of particle size analysis showed that Fe(OH) 3 particles with a mean size of 17.1 nm and Cu(OH) 2 particles with an average size of 6.65 μm were obtained. TG analysis and XRD patterns suggested that 673 K is the optimal calcination temperature. CO hydrogenation produced C + 2 OH with a high selectivity above 58 wt% by using the ultrafine particles as catalyst, and the total alcohol yield of 0.250 g·ml −1 ·h −1 was obtained when the contents of Al 2 O 3 and K were 88.61 wt% and 1.60 wt%, respectively.

Sulfonic Acid Resin–Catalyzed Oxidation of Aldehydes to Carboxylic Acids by Hydrogen Peroxide

Abstract Oxidation of benzaldehyde to benzoic acid can be performed efficiently with 30% H2O2 as the oxidant and sulfonic acid resin Amberlyst 15 as the catalyst. The reactivities of benzaldehyde derivatives are determined by both hindrance effect and electron effect of substituents, and benzaldehyde derivatives with electron-withdrawing group at the meta- or para-position are highly active and almost quantitatively converted into their corresponding acids. In addition, this method also works well for the oxidation of aliphatic aldehydes. The key characteristic of the procedure is that the catalyst is recyclable. GRAPHICAL ABSTRACT

Selective oxidation of cellulose catalyzed by NHPI/Co(OAc)2 using air as oxidant

With NHPI/Co(OAc)2 as catalyst and air as oxidant, carboxylic group functionalized cellulose was prepared by oxidation of cellulose in acetic acid. Fourier transform infrared spectroscopy was utilized to detect the generation of carboxylic group and the acid amount was determined by acid–base titration method. The present results revealed that C6 primary hydroxyl groups on glucose units were partly converted to carboxylic groups during the catalytic oxidation process. The degree of polymerization of oxidized cellulose, which was determined by viscosity measurement, decreased slightly as compared with its parent. The structure of cellulose was characterized by X-ray diffraction and scanning electron microscopy, and it was almost unchanged.

Promotion effect of nickel for Cu–Ni/γ-Al2O3 catalysts in the transfer dehydrogenation of primary aliphatic alcohols

Cu–Ni/γ-Al2O3 bimetallic catalysts were developed for anaerobic dehydrogenation of non-activated primary aliphatic alcohols to aldehydes. Systematic investigation about the promotion effect of nickel on the catalytic performance was carried out. Hydrogenation of C=C bond rather than C=O bond, was significantly improved over Cu–Ni/γ-Al2O3 catalyst by introducing nickel, which interprets the good conversion of primary aliphatic alcohols. This work would contribute to design new catalysts for dehydrogenation of primary aliphatic alcohols.