96-35-5Relevant articles and documents
Highly efficient mesostructured Ag/SBA-15 catalysts for the chemoselective synthesis of methyl glycolate by dimethyl oxalate hydrogenation
Zheng, Jianwei,Lin, Haiqiang,Zheng, Xinlei,Duan, Xinping,Yuan, Youzhu
, p. 129 - 133 (2013)
Ag/SBA-15 catalyst is found to exhibit excellent catalytic activity and long-term stability for the chemoselective hydrogenation of dimethyl oxalate to methyl glycolate. The size of Ag crystallites, which is markedly affected by the Ag loading levels and catalyst pretreatment conditions, is a key factor determining the reaction rate of the structure-sensitive hydrogenation but hardly influenced the product distribution. The best catalytic hydrogenation activity is obtained over the Ag/SBA-15 catalyst with an average Ag crystallite size of around 3.9 nm.
Catalyst consisting of Ag nanoparticles anchored on amine-derivatized mesoporous silica nanospheres for the selective hydrogenation of dimethyl oxalate to methyl glycolate
Cao, Yueqiang,Dong, Guilin,Li, Wei,Zaera, Francisco,Zheng, Sainan,Zhou, Jinghong,Zhou, Xinggui
, p. 155 - 162 (2020)
Developing efficient catalysts for the selective hydrogenation of dimethyl oxalate (DMO) is of great significance for the coal-based production of methyl glycolate (MG), but designing processes for this conversion is challenging. Herein we report an unprecedented catalytic performance for the selective hydrogenation of DMO to MG, achieved by using a catalyst based on Ag nanoparticles anchored inside the mesopores of amine-derivatized silica nanospheres (NH2-MSNS). It was determined that the unique microenvironment endowed by the amine-derivatized channel surfaces helps this Ag catalyst promote the activation of DMO and H2 to yield MG with high selectivity, and also prevents sintering and coking, hence improving stability. Accordingly, the resulting Ag/NH2-MSNS catalyst was shown to be capable of promoting the hydrogenation reaction with a turnover frequency of 230 h?1 and a MG selectivity of 97percent at nearly 100percent of DMO conversion, a performance that was sustained for at least 250 h; these results are significantly better than those seen with other reported catalysts. Our study points to a promising route for the development of high-performing Ag catalysts to be used in the coal-based MG production.
Oxidative esterification of ethylene glycol in methanol to form methyl glycolate over supported Au catalysts
Ke, Yi-Hu,Qin, Xiao-Xia,Liu, Chun-Ling,Yang, Rong-Zhen,Dong, Wen-Sheng
, p. 3141 - 3150 (2014)
Au/ZnO and Au/Al2O3 catalysts with various mean Au particle diameters (2.0-7.4 nm) were prepared by the deposition of pre-formed Au colloids. These catalysts were evaluated in the oxidative esterification of ethylene glycol to methyl glycolate. The results show that the catalytic activity per surface Au atom is independent of Au particle diameter in the range of 3-7.4 nm, whereas smaller Au particles (~2.0 nm) show an inferior activity. This behavior was observed on both Au/ZnO and Au/Al2O3 catalysts. This observed correlation between activity and Au particle diameter confirms the assertion that only exposed atoms are catalytically active. We prepared gold nanoparticles with a uniform mean diameter of ~3 nm loaded on various supports, i.e. ZnO, Al2O3, SiO2, TiO2 and CeO2. Among these five catalysts, Au/ZnO gave the best catalytic activity in the reaction followed by Au/Al2O 3. Au/SiO2, Au/TiO2 and Au/CeO2 gave significantly lower activities. The variation in catalytic behavior of these gold catalysts on different supports originates from differences in the anchoring of the supported Au particles, the gold oxidation state, the gold-support interaction, and the acidity of the support. the Partner Organisations 2014.
Effect of leaching temperature on structure and performance of Raney Cu catalysts for hydrogenation of dimethyl oxalate
Kong, Xiangpeng,Ma, Cailian,Zhang, Juan,Sun, Jiaqiang,Chen, Jiangang,Liu, Kefeng
, p. 153 - 160 (2016)
As-synthesized Raney Cu catalysts through selective leaching of Cu-Al (50 wt%Cu-50 wt%Al) alloy pellets in sodium hydroxide solution have been systematically investigated during the catalyst preparation process. Results reveal that the microstructures, physicochemical and surface properties of the Raney Cu catalysts depend profoundly on the leaching temperature. In gas-phase hydrogenation of dimethyl oxalate (DMO), the Raney Cu catalysts prepared at the mild leaching conditions tend to deactivate rapidly, the formation of methyl glycolate (MG). As-prepared catalysts at higher leaching temperature exhibit excellent stability, favoring the synthesis of ethylene glycol (EG). Especially, Raney Cu catalyst obtained at 40°C shows the superior stability and MG selectivity of 95.0% in DMO hydrogenation. Furthermore, the reasons for deactivation of Raney Cu catalyst in DMO hydrogenation have been discussed in detail.
Three dimensional Ag/KCC-1 catalyst with a hierarchical fibrous framework for the hydrogenation of dimethyl oxalate
Ouyang, Mengyao,Wang, Yue,Zhang, Jian,Zhao, Yujun,Wang, Shengping,Ma, Xinbin
, p. 12788 - 12791 (2016)
The novel fibrous nano-silica (KCC-1) based silver nanocatalyst exhibits excellent catalytic activity with a high TOF value (53.2 h-1) in the gas-phase hydrogenation of DMO to MG. Compared with the traditional mesoporous silica materials, KCC-1 remarkably enhances the accessibility of the silver active sites due to its three dimensional hierarchical channel structure.
Influence of La-doping on the CuO/ZrO2catalysts with different Cu contents for hydrogenation of dimethyl oxalate to ethylene glycol
Ding, Jian,Guo, Xiaohui,Liu, Huimin,Wang, Meihui,Wang, Yaxiong,Wang, Zhenfeng,Yu, Gewen
, p. 18102 - 18113 (2021/10/12)
Herein, Cu/ZrO2catalysts containing different Cu contents with or without La-doping were used for the selective hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). Effects of La addition and the optimal Cu content were thoroughly investigated. It was found that the Cu0/Cu+pairs located at interfacial sites for CuO/ZrO2catalysts with different Cu contents played an important role in the hydrogenation of DMO to EG. Interestingly, the La-doping could make the copper dispersion increase obviously. Besides, it greatly inhibited the crystal phase transformation from tetragonal to monoclinic zirconia regardless of being calcined at 750 °C. Meanwhile, the incorporation of La promoted the activation of hydrogen although resulting in a small increase in acidic/basic sites over the catalyst surface, which led to a higher conversion of DMO while the selectivity of EG decreased slightly. As a result, 97.2% selectivity of EG, which corresponds to 100% conversion of DMO, was achieved over the La-doped CuO/ZrO2catalyst with 33 wt% Cu content, which was also stable for more than 168 h on stream. This results revealed that the strong interaction between La promoters and Cu species was another type of important active site with high catalytic efficiency in addition to the Cu0/Cu+site of La-doped CuO/ZrO2?catalyst.
Hydrogenation of dimethyl oxalate to ethylene glycol over Cu/KIT-6 catalysts
Yu, Xinbin,Burkholder, Michael,Karakalos, Stavros G.,Tate, Gregory L.,Monnier, John R.,Gupton, B. Frank,Williams, Christopher T.
, p. 2403 - 2413 (2021/04/22)
Copper supported on KIT-6 mesoporous silica was preparedviaammonia evaporation (AE) method and applied for the catalytic hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). The high specific surface area and interconnected mesoporous channels of the support facilitated the dispersion of copper species. The effect of AE temperature and copper loading on the structure of catalysts and induced change in hydrogenation performance were studied in detail. The results showed that both parameters influenced the overall and/or intrinsic activity. The hydrogenation of DMO to EG was proposed to proceedviathe synergy between Cu0and Cu+sites and catalysts with high surface Cu0/Cu+ratio exhibited high intrinsic activity in the investigated range.
Promotional effect of indium on Cu/SiO2catalysts for the hydrogenation of dimethyl oxalate to ethylene glycol
Huang, Huijiang,Kong, Lingxin,Ma, Xinbin,Wang, Hui,Wang, Shengping,Wang, Xiaofei,Xu, Yuxi,Zhao, Yujun
, p. 6854 - 6865 (2021/10/25)
The synthesis of ethylene glycol (EG) through hydrogenation of syngas-derived dimethyl oxalate (DMO) has been a promising method because syngas can be obtained from plentiful resources such as coal, natural gas, biomass,etc.In this work, we fabricated several indium-promoted Cu/SiO2catalysts by a one-pot hydrolysis precipitation (HP) method for the DMO-to-EG reaction. The textural and physiochemical properties of the catalysts were revealed using multiple characterization methods. The intimate contact of Cu and In enhances the reduction of indium oxide and the formation of CuIn alloy. The introduction of indium also markedly improves the copper dispersion and formation of Cu0active sites, which improve the activation of H2. The plentiful interface of Cu+-CuIn alloy prompts the conversion of the carbonyl group adsorbed on the Cu+sites with the dissociated hydrogen on the vicinal CuIn alloy, which is confirmed by the higher TOF (Cu+) and the lower apparent activation energy (Ea) on the Cu1In/SiO2catalyst. Both CuIn alloy and Cu0species have a synergistic effect with Cu+, endowing the Cu1In/SiO2catalyst with a higher EG yield (96%) in comparison with the Cu/SiO2catalyst without doping.
Conversion of sugars to methyl lactate with exfoliated layered stannosilicate UZAR-S4
Murillo, Beatriz,de la Iglesia, óscar,Rubio, César,Coronas, Joaquín,Téllez, Carlos
, p. 90 - 96 (2020/04/27)
Biomass has been shown as an alternative to fossil fuels for obtaining chemicals. In this work, the transformation of sugars into methyl lactate (ML) at 160 °C was carried out using the layered stannosilicate UZAR-S3 (University of Zaragoza-solid number 3) and the delaminated material UZAR-S4 (University of Zaragoza-solid number 4) obtained from its exfoliation. The exfoliation of UZAR-S3 to UZAR-S4 increased the accessibility of the compounds to the catalytic sites and the medium-strength acidity. Thus, the yield to ML for sucrose transformation increased from 8% for UZAR-S3 to 49.9 % for UZAR-S4. In the reusability tests, the UZAR-S4 catalyst was characterized before and after reaction by several techniques such as X-ray diffraction, thermogravimetry analysis, scanning electronic microscopy, energy dispersive X-ray spectroscopy and nitrogen adsorption. A deactivation of the catalyst was observed, which was related to carbonaceous deposits that decreased the specific surface area and the pore volume of the catalyst.
Partial hydrogenation of dimethyl oxalate on Cu/SiO2 catalyst modified by sodium silicate
Huang, Huijiang,Wang, Bo,Wang, Yue,Zhao, Yujun,Wang, Shengping,Ma, Xinbin
, p. 68 - 73 (2019/09/12)
Cu/SiO2 catalyst modified with Na2SiO3 was prepared by the ammonia evaporation impregnation method and applied in the partial hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG). The addition of Na2SiO3 led to a serious shrinkage of those accumulation pores in the catalyst, but hardly affect the structure of the mesopores bellow 8 nm. Moreover, the trace amount of Na2SiO3 enhanced the formation of copper phyllosilicate, which resulted in a minor increment in Cu+ species as well as a decrease of Cu0 species. An unexpected high MG yield of about 83% and MG selectivity of 99.8% was achieved over the Cu/SiO2 catalyst modified with 0.5% Na2SiO3 in the partial hydrogenation of DMO. The loss of some smaller accumulation pores due to the presence of Na2SiO3 dopant could be key reason for the higher selectivity, because the larger pores can ensure the fast transfer of MG to the external surface. Thus, the further hydrogenation of MG can be prevented. Moreover, the decrement of Cu0 species induced by doping of Na2SiO3 could be another reason for the higher selectivity to MG, since insufficient activated H2 could be provided for the further hydrogenation of MG.
