Yizheng Huang

Conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts

The conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H2O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.

Gold Nanoclusters Confined in a Supercage of Y Zeolite for Aerobic Oxidation of HMF under Mild Conditions

Au nanoclusters with an average size of approximately 1 nm size supported on HY zeolite exhibit a superior catalytic performance for the selective oxidation of 5-hydroxymethyl-2-furfural (HMF) into 2,5-furandicarboxylic acid (FDCA). It achieved >99 % yield of 2,5-furandicarboxylic acid in water under mild conditions (60 °C, 0.3 MPa oxygen), which is much higher than that of Au supported on metal oxides/hydroxide (TiO2 , CeO2 , and Mg(OH)2 ) and channel-type zeolites (ZSM-5 and H-MOR). Detailed characterizations, such as X-ray diffraction, transmission electron microscopy, N2 -physisorption, and H2 -temperature-programmed reduction (TPR), revealed that the Au nanoclusters are well encapsulated in the HY zeolite supercage, which is considered to restrict and avoid further growing of the Au nanoclusters into large particles. The acidic hydroxyl groups of the supercage were proven to be responsible for the formation and stabilization of the gold nanoclusters. Moreover, the interaction between the hydroxyl groups in the supercage and the Au nanoclusters leads to electronic modification of the Au nanoparticles, which is supposed to contribute to the high efficiency in the catalytic oxidation of HMF to FDCA.

Silica-supported bidentate arsine palladium(0) complex: a highly active and stereoselective catalyst for arylation of conjugated alkenes

A silica-supported bidentate arsine palladium(0) complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The complex has been characterized by X-ray photoelectron spectroscopy and it is a highly active and stereoselective catalyst for arylation of styrene and acrylic acid with aryl halides affording a variety of trans-stilbenes and substituted trans-cinnamic acids in high yields.

Synthesis of silica-supported poly-γ-diphenylarsinopropylsiloxane palladium complex and its catalytic behavior for Heck carbonylation of aryl halides

A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide in THF and then the reaction with palladium chloride. It is an efficient catalyst for Heck carbonylation of aryl halides under atmospheric pressure of carbon monoxide. This polymeric palladium catalyst can be recovered and reused.

Catalytic oxidation of glycerol to tartronic acid over Au/HY catalyst under mild conditions

Gold nanoclusters or nanoparticles on various supports (CeO2, activated carbon, HY, REY, and NaY) were investigated for glycerol oxidation in the aqueous phase under mild conditions. Compared with other catalysts, Au/HY showed remarkable catalytic performance in forming dicarboxylic acid (tartronic acid) over the monocarboxylic acid (glyceric acid) or the C–C cleavage product (oxalic acid). Au/HY achieved 98% conversion of glycerol and 80% yield of tartronic acid at 60 °C under 0.3 MPa O2. Further characterization showed that the small size of Au clusters is the key factor for the high oxidation performance. In situ Fourier transform infrared spectroscopy revealed that glycerol was first transformed to glyceric acid, and then glyceric acid was directly oxidized to tartronic acid.

Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural promoted by metal halides

The promotion effect of alkali metal halides toward the alcl3-catalyzed conversion of glucose to 5-hydroxymethylfurfural (hmf) was investigated. the results show that naf inhibited the reaction. however, nai and nabr promoted the reaction significantly, and the promotion effect of nai was more obvious than that of nabr. in n,n-dimethylacetamide (dmac), when nai was used as an additive for the alcl3-catalyzed conversion of glucose at 130 degrees c for 15 min, glucose conversion increased from 71% to 86%, and the hmf yield increased from 36% to 62%. the alcl3-nai-dmac system could also be used for the catalytic conversion of other carbohydrates such as fructose, mannose, sucrose, maltose, cellobiose, and inulin to hmf. when sucrose was used as the feedstock, a 63% hmf yield was achieved. (c) 2014, dalian institute of chemical physics, chinese academy of sciences. published by elsevier b.v. all rights reserved.

Novel stereoselective synthesis of (E)-cinnamonitriles via Heck arylation of acrylonitrile catalysed by a silica-supported bidentate arsine palladium(0) complex

(E)-Cinnamonitriles have been synthesised stereoselectively in high yields via Heck arylation of acrylonitrile with aryl iodides catalysed by a silica-supported bidentate arsine palladium(0) complex. This polymeric palladium(0) complex can be recovered and reused without noticeable loss of activity.