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In situ IR study of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO_2 catalyst

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Journal of Natural Gas Chemistry 2012年第6期21卷 753-758页

作者： Shengguo Hui Bo Zhang Suhua Zhang Wei Li State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

The mechanism of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst was investigated by in situ Fourier transform infrared （FTIR） spectroscopy. It was found that dimethyl oxalate and methyl glycolate proceeded via dissociative adsorption on Cu/SiO2 catalyst, and four main intermediates, CH3OC（O）（O）C-M （1655 cm-1）, M-C（O）（O）C-M （1618 cm-1）, HOCH2（O）C--M （1682 cm-1） and CH3O-M （2924-2926 cm-1）, were identified during the reaction. It was concluded that dimethyl oxalate hydrogenation to ethylene glycol mainly proceeded along the route： dimethyl oxalate ／rightarrow CH3OC（O）（O）C-M → methyl glycolate →HOCH2（O）C-M → ethylene glycol. Finally a schematic reaction network was proposed.

关键词： dimethyl oxalate ethylene glycol FTIR hydrogenation Cu/SiO2

Effect of copper loading on texture,structure and catalytic performance of Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

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Journal of Natural Gas Chemistry 2012年第5期21卷 563-570页

作者： Bo Zhang Shengguo Hui Suhua Zhang Yang Ji Wei Li Dingye Fang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Pujing Chemical Industry(Sha)Limited Shanghai 200231China

Cu/SiO2 catalysts prepared by a convenient and efficient method using the urea hydrolysis deposition-precipitation （UHDP） technique have been proposed focusing on the effect of copper *** texture,structure and composition are systematically characterized by ICP,FTIR,N 2-physisorption,N2O chemisorption,TPR,XRD and *** formation of copper phyllosilicate is observed in Cu/SiO2 catalyst by adopting UHDP method,and the amount of copper phyllosilicate is related to copper *** is found the structure properties and catalytic performance is profoundly affected by the amount of copper *** excellent catalytic activity is attributed to the synergetic effect between Cu0 and Cu ＋.DMO conversion and EG selectivity are determined by the amount of Cu0 and Cu＋,*** proper copper loading （30 wt%） provides with the highest ratio of Cu ＋ /Cu0,giving rise to the highest EG yield of 95% under the reaction conditions of p=2.0 MPa,T=473 K,H2/DMO=80 and LHSV=1.0h-1.

关键词： Cu/SiO2 copper loading dimethyl oxalate ethylene glycol copper phyllosilicate

Paired-Pd(Ⅱ) centers embedded in HKUST-1 framework: Tuning the selectivity from dimethyl carbonate to dimethyl oxalate

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Journal of Energy Chemistry 2022年第4期31卷 233-240页

作者： Hong-Zi Tan Zhe-Ning Chen Kai-Qiang Jing Jing Sun Yu-Ping Xu Ning-Ning Zhang Zhong-Ning Xu Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Chemistry&Chemical Engineering Shandong University of TechnologyZibo 255049ShandongChina School of Chemistry and Chemical Engineering Liaocheng UniversityLiaocheng 252000ShandongChina

CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.

关键词： CO Methyl nitrite Oxidative coupling dimethyl oxalate Paired-Pd(Ⅱ)centers HKUST-1

Synthesis of Methyl Glycolate by Hydrogenation of dimethyl oxalate over Cu-Ag/SiO_2 Catalyst

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Journal of Natural Gas Chemistry 2007年第1期16卷 78-80页

作者： Baowei Wang Qian Xu Hua Song Genhui Xu School of Chemical Engineering and Technology Key Lab for Green Chemical Technology Tianjin University Tianjin 300072 China

Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.

关键词： dimethyl oxalate methyl glycolate ethylene glycol hydrogenation Cu-Ag/SiO2 catalyst

Catalytic Performance and Texture of TEOS Based Cu/SiO_2 Catalysts for Hydrogenation of dimethyl oxalate to Ethylene Glycol

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Chemical Research in Chinese Universities 2012年第1期28卷 119-123页

作者： WANG Shu-rong, YIN Qian-qian and LI Xin-bao State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China Zhejiang University State Key Laboratory of Clean Energy Utilization Hangzhou 310027

Highly active and selective Cu/SiO2 catalysts for hydrogenation of dimethyl oxalate（DMO） to ethylene glycol（EG） were successfully prepared by means of a convenient one-pot synthetic method with tetraethoxysi lane（TEOS） as the source of silica. XRD, H2-TPR, SEM, TEM, XRF and N2 physisorption measurements were performed to characterize the texture and structure of Cu/SiO2 catalysts with different copper loadings. The active components were highly dispersed on SiO2 supports. Furthermore, the coexistence of Cu0 and Cu＋ contributed a lot to the excellent performance of Cu-TEOS catalysts. The DMO conversion reached 100% and the EG selectivity reached 95% at 498 K and 2 MPa with a high liquid hourly space velocity over the 27-Cu-TEOS catalyst with an actual cop per loading of 19.0%（mass fraction）.

关键词： Cu/SiO2 TEOS Hydrogenation dimethyl oxalate Ethylene glycol

Preparation of Diphenyl oxalate from Transesterification of dimethyl oxalate with Phenol over TS-1 Catalyst

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Chinese Chemical Letters 2003年第5期14卷 461-464页

作者： Xin Bin MA Sheng Ping WANG Hong Li GUO Gen Hui XU State Key Laboratory of C1 Chemistry and Technology School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072

Diphenyl oxalate was synthesized from transesterification of dimethyl oxalate with phenol over TS-1 ( 2.5 wt% Ti ) catalyst. TS-1 catalyst, as a heterogeneous catalyst, showed excellent selectivity of diphenyl oxalate and methylphenyl oxalate compared with other homogeneous catalysts. Lewis acid sites on TS-1 catalyst were the active sites for transesterification of dimethyl oxalate with phenol. The high selectivity was closely related to the weak acid sites over TS-1.

关键词： Diphenyl oxalate transesterification dimethyl oxalate weak acid sites TS-1.

Effects of ethanol on the in situ synthesized Cu/SiO_2 catalyst:Texture,structure,and the catalytic performance in hydrogenation dimethyl oxalate to ethylene glycol

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Chinese Chemical Letters 2011年第3期22卷 362-365页

作者： Shu Rong Wang Ling Jun Zhu Ying Ying Zhu Xiao Lan Ge Xin Bao Li State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

The Cu/SiO_2 catalysts were in situ synthesized by the hydrolysis of tetraethyl orthosilicate（TEOS） in one phase solution using ethanol as co-solvent or TEOS/H_2O two phases solution,followed by the precipitation of copper on SiO_2 by ammonia evaporation. In the hydrogenation of dimethyl oxalate,the catalyst prepared by one phase hydrolysis exhibited higher activity and ethylene glycol（EG） selectivity at lower temperature than that of two phases due to its larger BET surface area and multimodal pore *** 488-503 K,the catalyst prepared in one phase solution with water/ethanol（W/E） volume ratio of 3：1 exhibited 90- 95%EG selectivity,while catalyst prepared by two phase hydrolysis reached 90%EG selectivity only at 498-503 K.

关键词： Ethanol Cu/SiO2 TEOS Hydrogenation dimethyl oxalate Ethylene glycol

Pd-Fe/a-AI203/cordierite monolithic catalysts for the synthesis of dimethyl oxalate： effects of calcination and structure

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Frontiers of Chemical Science and Engineering 2012年第3期6卷 259-269页

作者： Shengping WANG Xin ZHANG Yujun ZHAO Yadong GE Jing LV Baowei WANG Xinbin MA Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Cordierite monoliths coated with Pd-Fe/a- Al2O3 catalysts were prepared at various calcination temperatures and characterized by thermogravimetry, temperature-programmed reduction, transmission electron microscopy, diffuse reflectance infrared Fourier transfor- mation spectroscopy and X-ray diffraction. The performance of the catalytic monoliths for the synthesis of dimethyl oxalate （DMO） through a CO coupling reaction was evaluated. Monolithic catalysts with calcination temperatures ranging from 473 K to 673 K exhibited excellent dispersion of Pd, good CO adsorption properties, and excellent performance for the coupling reaction. The optimized monolithic catalyst exhibited a much higher Pd efficiency （denoted as DMO （g）.Pd （g）-1 h 1）（733h-1） than that of the granular catalyst （60.2 h-1）, which can be attributed to its honeycomb structure and the large pore sizes in the a-Al2O3 washcoat which was accompanied with an even distribution of the active component in the coating layer along the monoliths channels.

关键词： dimethyl oxalate coupling Pd cordierite,monolith calcination structure

Heterogeneous Cu_2O-mediated ethylene glycol production from dimethyl oxalate

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Journal of Energy Chemistry 2016年第3期25卷 507-511页

作者： Lu Li Dezhang Ren Jun Fu Yunjie Liu Fangming Jin Zhibao Huo School of Environmental Science and Engineering the State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University State Key Laboratory of Fine Chemicals Dalian University of Technology

An efficient process for the conversion of dimethyl oxalateinto ethylene glycol with high selectivity and high yield over CuO was investigated. In situ formed Cu as a true catalytically active species showed a good ca... 详细信息

关键词： dimethyl oxalate Ethylene glycol Cu_2O Hydrothermal reactions Chemicals