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Highly efficient mesostructured Ag/SBA-15 catalysts for the chemoselective synthesis of methyl glycolate by dimethyl oxalate hydrogenation
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.
Zheng, Jianwei,Lin, Haiqiang,Zheng, Xinlei,Duan, Xinping,Yuan, Youzhu
p. 129 - 133
(2013)
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Catalyst consisting of Ag nanoparticles anchored on amine-derivatized mesoporous silica nanospheres for the selective hydrogenation of dimethyl oxalate to methyl glycolate
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.
Cao, Yueqiang,Dong, Guilin,Li, Wei,Zaera, Francisco,Zheng, Sainan,Zhou, Jinghong,Zhou, Xinggui
p. 155 - 162
(2020)
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Oxidative esterification of ethylene glycol in methanol to form methyl glycolate over supported Au catalysts
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.
Ke, Yi-Hu,Qin, Xiao-Xia,Liu, Chun-Ling,Yang, Rong-Zhen,Dong, Wen-Sheng
p. 3141 - 3150
(2014)
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Effect of leaching temperature on structure and performance of Raney Cu catalysts for hydrogenation of dimethyl oxalate
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.
Kong, Xiangpeng,Ma, Cailian,Zhang, Juan,Sun, Jiaqiang,Chen, Jiangang,Liu, Kefeng
p. 153 - 160
(2016)
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Three dimensional Ag/KCC-1 catalyst with a hierarchical fibrous framework for the hydrogenation of dimethyl oxalate
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.
Ouyang, Mengyao,Wang, Yue,Zhang, Jian,Zhao, Yujun,Wang, Shengping,Ma, Xinbin
p. 12788 - 12791
(2016)
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Hydrogenation of dimethyl oxalate to ethylene glycol over Cu/KIT-6 catalysts
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.
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)

Influence of La-doping on the CuO/ZrO2catalysts with different Cu contents for hydrogenation of dimethyl oxalate to ethylene glycol
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.
Ding, Jian,Guo, Xiaohui,Liu, Huimin,Wang, Meihui,Wang, Yaxiong,Wang, Zhenfeng,Yu, Gewen
p. 18102 - 18113
(2021/10/12)

Promotional effect of indium on Cu/SiO2catalysts for the hydrogenation of dimethyl oxalate to ethylene glycol
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.
Huang, Huijiang,Kong, Lingxin,Ma, Xinbin,Wang, Hui,Wang, Shengping,Wang, Xiaofei,Xu, Yuxi,Zhao, Yujun
p. 6854 - 6865
(2021/10/25)

Conversion of sugars to methyl lactate with exfoliated layered stannosilicate UZAR-S4
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.
Murillo, Beatriz,de la Iglesia, óscar,Rubio, César,Coronas, Joaquín,Téllez, Carlos
p. 90 - 96
(2020/04/27)

Method for Catalytically Hydrogenating Oxalates
The invention discloses a method for catalytically hydrogenating oxalates. In the method, an oxalate and hydrogen gas are contacted with a nanotube assembled hollow sphere catalyst, to produce a product comprising glycolate or glycol. The predominant chemical components of the catalyst include copper and silica, in which the copper is in an amount of 5 to 60% by weight of the catalyst, and the silica is in an amount of 40-95% by weight of the catalyst. The catalyst has a specific surface area of 450-500 m2/g, an average pore volume of 0.5-1 cm3/g, and an average pore diameter of 5-6 nm. The catalyst is in a structure of assembling nanotubes on hollow spheres, wherein the hollow spheres have a diameter of 50-450 nm, and a wall thickness of 10-20 nm, and the nanotubes, vertically arranged on the surfaces of the hollow spheres, have a diameter of 3-5 nm, and a length of 40-300 nm. Even in the case of a low H2/DMO feeding ratio, the method of the invention still can exhibit an excellent activity of hydrogenating oxalates and an excellent selectivity to ethylene glycol, and reduce circulation quantity of hydrogen gas, thereby to save power costs and apparatus costs, and it can flexibility adjust the selectivity of ethylene glycol and glycolate. Thus, the method has high industry prospects and application values.
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Paragraph 0041; 0057

(2020/05/29)

A boron-doped carbon aerogel-supported Cu catalyst for the selective hydrogenation of dimethyl oxalate
Carbon aerogels (CA) were applied in the synthesis of Cu/CA catalysts by the impregnation method and the catalysts with boron-doped CA supports were systematically characterized and evaluated in the hydrogenation of dimethyl oxalate (DMO). The Cu/xB-CA catalyst with 25 wt% copper showed 100% DMO conversion and the highest ethylene glycol (EG) or methyl glycolate (MG) selectivity of 70% at 230 °C as well as a lifetime of over 150 h. The characterization results disclosed the reason the performance of the catalysts could be tuned facilely by changing the amount of boron doping, which effectively influenced the interrelation between copper and CA, acidity and alkalinity of catalysts and Cu dispersion. Both the original carbon aerogels and that promoted with little B could provide larger surface areas and high dispersion of the metal. The species, size of copper particles and the ratio of Cu+/(Cu+ + Cu0) could be regulated by boron doping, thus adjusting the type of hydrogenation products.
Lu, Xiaodong,Lu, Xiaodong,Wang, Guofu,Yang, Yu,Kong, Xiangpeng,Chen, Jiangang
p. 3232 - 3240
(2020/03/06)

Use of lithium aryloxides as promoters for preparation of α-hydroxy acid esters
In this work, a hexanuclear lithium compound, [Li6(MesalO)6] (1), supported by a chelating ligand, namely methyl salicylato (MesalOH), was used as a precursor for preparation of the monomeric lithium aryloxides [Li(MesalO)(MesalOH)] (2) and [Li(MesalO)(MeOH)2] (3) via reactions with MesalOH or MeOH. These aryloxides were characterized by single-crystal X-ray diffraction, and spectroscopic and other analytical methods. The diffusion-ordered 1H NMR measurements revealed the retention of solid-state structures of 1 and 2 in THF-d8 solution. Experimental data obtained for 3 showed its decomposition into compound 1 and free MeOH. Compound 1 generated from 3 was also used as a catalyst for the alcoholysis of l-lactide (l-LA) and glycolide (GA) for the preparation of α-hydroxy acid esters. We established that during methanolysis in the presence of 1, l-LA was selectively transformed into methyl (S,S)-O-lactyllactate (MeL2), and GA was converted to methyl glycolate (MeG1) and oligoglycolate esters MeGn (n = 2, 3, and 4).
Petrus, Rafa?,Fa?at, Patryk,Sobota, Piotr
supporting information
p. 866 - 876
(2020/01/30)

Preparation method of glycolic acid or glycolate
The invention discloses a preparation method of glycolic acid or glycolate. The method comprises the following steps of: formaldehyde and carbon monoxide are introduced into a reactor containing a reaction solution to carry out polymerization reaction, wherein the reaction solution contains an acid catalyst; after the relative molecular mass of a polymer generated by the polymerization reaction reaches 2,000 and above, the polymerization reaction system is cooled to crystallize and precipitate the generated polymer; solid-liquid separation is carried out on the material in the reactor; and excessive water or alcohol is added into the obtained solid phase to carry out a depolymerization reaction to obtain glycolic acid or glycolate. Compared with the prior art, the method disclosed by the invention is good in process stability, low in energy consumption, good in economic practicability and high in product yield, and has a very good application prospect.
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Paragraph 0132-0134; 0145-0147

(2020/09/20)

Partial hydrogenation of dimethyl oxalate on Cu/SiO2 catalyst modified by sodium silicate
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.
Huang, Huijiang,Wang, Bo,Wang, Yue,Zhao, Yujun,Wang, Shengping,Ma, Xinbin
p. 68 - 73
(2019/09/12)

Metal complex and preparation method and application thereof
The invention discloses a post-transition metal bisphosphine diamine complex catalyst which is good in substrate applicability, and capable of efficiently catalyzing a hydrogenation alcohol productionreaction of various carbonyl derivatives such as esters, amides and carbonates different in structure. Central metal coordination of the metal complex catalyst has two diaminodiphosphine ligands o-PPh2C6H4NR1R2 and Ph2PCH2CH2NR3R4 (or o-PPh2C6H4CH2NR3R4, Ph2P(CH2) 3NR3R4) different in structure, and the metal complex can be obtained through a simple two-step synthesis method. The catalysts show the advantages of the two ligands in the catalytic hydrogenation process, and the defects of a complex catalyst formed by a single ligand in the aspect of applicability of substrates can be effectivelyovercome.
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Paragraph 0034; 0036

(2019/06/07)

SYNTHESIS OF GLYCOLS VIA TRANSFER HYDROGENATION OF ALPHA-FUNCTIONAL ESTERS WITH ALCOHOLS
A transfer hydrogenation process for forming vicinal diols by hydrogenating 1,2-dioxygenated organic compounds using alcohols as the reducing agent instead of the traditional H2 gas. The transfer hydrogenation is carried out under milder conditions of temperature and pressure than is typical for ester hydrogenation with H2. The milder conditions of operation provide benefits, such as lower operating and capital costs for industrial scale production as well as savings in product purification due to the avoidance of by-products from exposure of reaction mixtures and products to high temperatures.
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Paragraph 0095; 0096

(2019/02/17)

Ruthenium complexes with N-functionalized secondary amino ligands: a new class of catalysts toward efficient hydrogenation of esters
A series of ruthenium complexes (o-PPh2C6H4NHR)2RuCl2 (R = Me, 3; Et, 4; CH2Ph, 5) and (o-PPh2C6H4NH2)[(CH2NHR)2]RuCl2 (R = Me, 7; Et, 8; iPr, 9) modulated with mono-N-functionalized secondary amino ligands were synthesized and demonstrated as efficient catalysts in the hydrogenation of esters into alcohols. The catalytic performances of these new complexes are much better than their corresponding primary amino ligand-constituted complexes (o-PPh2C6H4NH2)2RuCl2 (2) and (o-PPh2C6H4NH2)[(CH2NH2)2]RuCl2 (6). The significant improvement is attributed to the increased electron density of the secondary amino ligand in comparison with that of the primary amino ligand.
Fang, Xiaolong,Li, Bin,Zheng, Jianwei,Wang, Xiaoping,Zhu, Hongping,Yuan, Youzhu
supporting information
p. 2290 - 2294
(2019/02/19)

Selective Protection of Secondary Alcohols by Using Formic Acid as a Mild and Efficient Deprotection Reagent for Primary tert -Butyldimethylsilyl Ethers
A mild, efficient, and environmentally friendly method for the selective protection of secondary hydroxyl groups is described. The method involves the protection of both primary and secondary hydroxyl groups as tert -butyldimethylsilyl (TBDMS) ethers and selective deprotection of the primary TBDMS group with formic acid in acetonitrile/water. The rates of desilylation of primary and secondary TBDMS ethers by different concentrations of formic acid are determined. Formic acid of 5-20% concentration is found to selectively deprotect primary TBDMS ethers while keeping more than 95% of their secondary counterparts intact.
Sapkota, Krishna,Huang, Faqing
supporting information
p. 1895 - 1898
(2019/09/30)

Base-free conversion of glycerol to methyl lactate using a multifunctional catalytic system consisting of Au-Pd nanoparticles on carbon nanotubes and Sn-MCM-41-XS
Multifunctional catalytic systems consisting of physical mixtures of (i) bimetallic Au-Pd nanoparticles (average size of 3-5 nm) supported on functionalised carbon nanotubes (CNTs) and (ii) Sn-MCM-41 nanoparticles (50-120 nm), were synthesised and investigated for the base-free, selective conversion of glycerol to methyl lactate in a batch reactor. The catalysts were characterised by means of transmission electron microscopy, N2-physisorption, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and by Boehm titration. The catalyst based on bimetallic AuPd/CNTs showed much higher activity than the monometallic Au or Pd counterparts, thus indicating synergetic effects. Functionalisation of the CNTs by oxidative treatments had a positive effect on catalyst performance, which was correlated to the observed increase in surface acidity and hydrophilicity. The highest yield of methyl lactate achieved in this work was 85% at 96% glycerol conversion (140 °C, 10 h at 30 bar air), which is the highest yield ever reported in the literature so far. Insights in the reaction pathway were obtained by monitoring the conversion-time profiles for intermediates and their possible role as inhibitors. Batch recycling experiments demonstrated the excellent reusability of the catalyst.
Tang, Zhenchen,Boer, Dina G.,Syariati, Ali,Enache, Mihaela,Rudolf, Petra,Heeres, Hero J.,Pescarmona, Paolo P.
p. 4115 - 4126
(2019/08/12)

Metal complex catalyst as well as preparation method and application thereof (by machine translation)
The invention provides a phosphine amine, diamine ligand transition metal complex catalyst containing a secondary amine functional group and a preparation method and application, and relates to a carbonyl derivative molecular hydrogenation alcohol metal complex catalyst capable of efficiently catalyzing ester, aldehyde, ketone and the like under the condition of lower additive usage. O-PPh coordinated with catalyst metal center2 C6 H4 NHR1 Ligands and o-PPh2 C6 H4 NHR2 Ligands or o-PPh2 C6 H4 NHR1 Ligands and R2 HNNCH2 CH2 NHR3 Ligands, which can be prepared by a simple two-step synthesis method. In the process of participating in the catalytic hydrogenation reaction, only a small amount of auxiliary "base" is needed to obtain excellent catalytic hydrogenation performance, and the defect. (by machine translation)
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Paragraph 0038-0046; 0066-0073

(2019/07/29)

Methods of catalytic hydrogenation for ethylene glycol formation
Embodiments described herein generally relate to hydrogenation catalysts, syntheses of hydrogenation catalysts, and apparatus and methods for hydrogenation. Methods for forming a hydrogenation catalyst may include mixing a silica generating precursor with a copper precursor and adding an ammonium salt to an end pH of between about 5 to about 9. Methods for hydrogenating an oxalate may include forming a reaction mixture by flowing a hydrogenation catalyst to a reactor, flowing a hydrogen source to the reactor, and flowing an oxalate to the reactor, wherein the hydrogenation catalyst has a particle size between about 10 nm to about 40 nm. Methods may further include reacting the oxalate to form ethylene glycol.
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Page/Page column 8-9

(2018/10/24)

Preparation method of chlorophenoxyacetic ester
The invention provides a preparation method of chlorophenoxyacetic ester, wherein the preparation method comprises the following steps: A) carrying out reaction of glycolic acid and alcohol in tolueneto obtain glycolic ester; B) carrying out reaction of glycolic ester and metal alkoxide to obtain a metal salt of glycolic ester; and C) carrying out reaction of the metal salt of glycolic ester andchlorobenzene to obtain the chlorophenoxyacetic ester. The chlorophenoxyacetic ester is synthesized by condensation of chlorobenzene with the metal salt of glycolic ester, the use of chlorophenol withunpleasant odor is effectively avoided, the production of highly toxic dioxins is eliminated, and the product quality and the operating environment of the production site are greatly improved. Motherliquor containing effective ingredients cannot be produced, so the loss of effective ingredients is effectively avoided and the yield of the product is improved.
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Paragraph 0058; 0059

(2019/01/08)

Catalytic Gas-Phase Cyclization of Glycolate Esters: A Novel Route Toward Glycolide-Based Bioplastics
A catalytic process to produce glycolide, the cyclic dimer of glycolic acid (GA), is proposed. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. Instead of the current industrial two-step route, which involves the polycondensation of GA and a subsequent backbiting reaction, a new route based on the gas-phase transesterification of methyl glycolate (MGA) over a fixed catalyst bed is presented. With specific supported TiO2 catalysts, a high glycolide selectivity of 75–78 % can be achieved at the thermodynamically-limited equilibrium conversion of MGA (54 % at 300 °C, 5.6 vol% MGA, 1 atm). The absence of solvent and the continuous nature of the process should allow for easy product separation and recycling of unconverted esters, while the few side-products, i. e. linear alkyl glycolate dimers and trimers seem recoverable via methanolysis. The reaction is compared to the cyclization of other α-hydroxy esters, such as methyl lactate to lactide, over the same catalysts, in terms of kinetics and thermodynamics. The absence of a methyl substitution on the α-carbon seems to lead to faster cyclization kinetics of MGA when compared to methyl lactate or the double-substituted methyl-2-hydroxy-isobutyrate. Contrarily, glycolide production is less favored thermodynamically compared to lactide. The absence of glycolide decomposition at temperatures up to 300 °C however allows to increase equilibrium conversion by taking the endergonic reaction to higher temperatures.
De Clercq, Rik,Makshina, Ekaterina,Sels, Bert F.,Dusselier, Michiel
p. 5649 - 5655
(2018/12/04)

Sonochemical synthesis of Zn-promoted porous MgO-supported lamellar Cu catalysts for selective hydrogenation of dimethyl oxalate to ethanol and their long-term stability
The environmentally benign hydrogenation reaction of dimethyl oxalate (DMO) to produce the important platform chemicals methyl glycolate (MG), ethylene glycol (EG) and ethanol (EtOH) has gained significant importance in recent years. In this work, novel and highly efficient catalysts composed of Zn-doped lamellar Cu nanocrystals supported on porous MgO nanoparticles were synthesized using an innovative and facile sonochemical approach, and applied in the DMO hydrogenation reaction. The obtained catalytic activity revealed that the addition of Zn was found to significantly enhance the catalytic performance. The product selectivity dramatically changed from MG selectivity (88%) for the un-doped catalyst to a high EtOH selectivity of 98% for the Zn-doped Cu/MgO catalyst. To understand the relationship between the catalyst structure and the catalytic performance, the prepared, reduced and spent Cu/MgO and Zn-doped Cu/MgO catalysts were thoroughly characterized using XRD, TEM, HR-TEM, EDS mapping analysis, N2 physical adsorption, XPS, Cu-LMM, FTIR and H2-TPR techniques. The enhancement in the deep hydrogenation reaction for the Zn-doped catalyst to produce high EtOH selectivity is attributed to the improved dispersion, crystal defects, surface segregation and the synergistic ratio effect between Cu0/(Cu0 + Cu+) in the catalyst. Moreover, the produced catalysts maintained high efficiency for DMO conversion and EtOH selectivity with long-term stability for at least 200 h. The developed sonochemical approach in this study seems to be promising for the green and surfactant-free aqueous synthesis of highly efficient heterogeneous catalysts.
Abbas, Mohamed,Zhang, Juan,Chen, Zheng,Chen, Jiangang
p. 17553 - 17562
(2018/11/01)

Direct conversion of C6 sugars to methyl glycerate and glycolate in methanol
The present work deals with the one-pot conversion of C6 sugars to methyl glycerate and glycolate via a cascade of retro-aldol condensation and oxidation processes catalyzed by using MoO3 as the Lewis acid catalyst and Au/TiO2 as the oxidation catalyst in methanol. Methyl glycerate (MGLY) is the product of C6 ketose (fructose), while methyl glycolate (MG) is produced from C6 aldose (mannose, glucose). It is found that a good one-pot match between two reactive processes is the key to the production of MGLY and MG with high yield (27.6% MGLY and 39.2% MG). A separated retro-aldol condensation and oxidation process greatly decreases their yields, and even no MGLY can be obtained in this separated process. We attribute this to high instability of glyceraldehyde/glycolaldehyde and their different reaction pathways which mainly depend on whether acetalization of retro-aldol products (glyceraldehyde and glycolaldehyde) occurs with methanol or not. This result opens a new prospect on the accumulation of C3 products other than lactate from biomass-derived carbohydrates.
Feng, Lei,Li, Gang,Yan, Yueer,Hou, Wenrong,Zhang, Yahong,Tang, Yi
p. 30163 - 30170
(2018/09/11)

Method for hydrogenation synthesis of ethylene glycol from oxalate
The invention relates to a method for catalytic hydrogenation synthesis of ethylene glycol from oxalate. The method mainly solves the problem that the existing catalytic reaction process for oxalate hydrogenation synthesis of ethylene glycol has low selectivity and a short catalyst life. Metal copper or copper oxide is used as an active component in the catalyst, hydrophilic silica or modified hydrophilic silica is used as a carrier and an appropriate metal oxide assistant is used. The catalyst has high reaction performances and reaction stability.
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Paragraph 0060-0064; 0066-0067; 0070-0071; 0074-0076

(2018/04/02)

Highly dispersed, ultra-small and noble metal-free Cu nanodots supported on porous SiO2 and their excellent catalytic hydrogenation of dimethyl oxalate to methyl glycolate
The production of methyl glycolate (MG) from the catalytic hydrogenation of dimethyl oxalate (DMO) derived from syngas (H2 + CO) as an environmentally benign and economical route has attracted tremendous interest in the modern chemical industry. Silica-supported noble and transition metal elements have been employed as efficient catalyst materials for this reaction. In this paper, we used a novel, highly efficient and eco-friendly sonochemical approach to synthesize noble metal-free, ultra-small and highly dispersed Cu nanodots wrapped on porous SiO2 catalysts. The hydrothermal method as a well-known conventional approach is used to synthesize the same catalyst of Cu/SiO2. The synthesized catalysts were exposed to the industrially relevant vapor-phase hydrogenation reaction of dimethyl oxalate, and then the calcined, reduced and spent catalysts were fully characterized using XRD, TEM, HR-TEM, N2 physical adsorption, FTIR, XPS, Cu-LMM and H2-TPR. Notably, the obtained results confirmed that the sonochemically synthesized noble metal-free Cu/SiO2 catalyst displayed remarkably high MG selectivity of 94% and a turnover frequency (TOF) of 5.08 h-1 compared with 81% MG selectivity and 3.45 h-1 TOF for the hydrothermally synthesized catalyst. These results could be attributed to the synergistic and high value of the Cu+/(Cu+ + Cu0) ratio for the synthesized catalyst and the high dispersion and surface area of the nanoparticles. Our ultrasonication technique holds promise for the synthesis of highly dispersed and efficient heterogeneous catalytic materials in aqueous medium with a short reaction time.
Abbas, Mohamed,Chen, Zheng,Zhang, Juan,Chen, Jiangang
p. 10290 - 10299
(2018/06/18)

Shape- and size-controlled synthesis of Cu nanoparticles wrapped on RGO nanosheet catalyst and their outstanding stability and catalytic performance in the hydrogenation reaction of dimethyl oxalate
Considerable interest has been paid in the last few years to the important environmentally benign catalytic hydrogenation reaction of dimethyl oxalate (DMO) to produce methyl glycolate (MG), ethylene glycol (EG) and ethanol (ETOH). SiO2-supported noble metal elements, such as Au, Ag and Ru, have been nominated as efficient catalysts for the production of high MG selectivity. In this work, noble-metal-free Cu nanoparticles wrapped on reduced graphene oxide (RGO) nanosheets were synthesized using a green in situ sonochemical method in an aqueous medium and then applied without the calcination step as a robust catalyst in the DMO hydrogenation reaction. Moreover, the effects of ultrasound (US), ammonia (NH4OH), a combination of both US and NH4OH, and Cu loading (10, 25 and 45 wt%) on the morphology and catalytic performance of the produced Cu/RGO catalysts were studied in detail. Interestingly, transmission electron microscopy images revealed that a dramatic morphology evolution of the Cu catalysts from ultra small dots to elongated and leaf-like nanoparticles shapes occurred, depending on simple modification of the reaction parameters. Notably, the obtained catalytic results demonstrated that among the different produced six catalysts, the prepared Cu/RGO catalyst using 20 kHz of ultrasound and in the presence of ammonia with 25 wt% Cu loading displayed the highest MG selectivity (98.8%) at a relatively low reaction temperature (210 °C), while, the synthesized Cu/RGO catalyst with 45 wt% Cu loading exhibited the highest ETOH selectivity (94%) at 240 °C. Moreover, both catalysts showed long-term stability for at least 300 h while maintaining the high DMO conversion and selectivity ratio. The comprehensive characterization to the as-prepared, reduced and spent catalysts concluded that the synergistic ratio of Cu+/(Cu+ + Cu0), the high dispersion of Cu nanoparticles, the defective edges, sites and electron transfer provided from RGO were the main reasons for the obtained superior catalytic activity and long-term stability.
Abbas, Mohamed,Chen, Zheng,Chen, Jiangang
supporting information
p. 19133 - 19142
(2018/10/20)

Chemocatalytic Conversion of Cellulosic Biomass to Methyl Glycolate, Ethylene Glycol, and Ethanol
Production of chemicals and fuels from renewable cellulosic biomass is important for the creation of a sustainable society, and it critically relies on the development of new and efficient transformation routes starting from cellulose. Here, a chemocatalytic conversion route from cellulosic biomass to methyl glycolate (MG), ethylene glycol (EG), and ethanol (EtOH) is reported. By using a tungsten-based catalyst, cellulose is converted into MG with a yield as high as 57.7 C % in a one-pot reaction in methanol at 240 °C and 1 MPa O2, and the obtained MG can be easily separated by distillation. Afterwards, it can be nearly quantitatively converted to EG at 200 °C and to EtOH at 280 °C with a selectivity of 50 % through hydrogenation over a Cu/SiO2 catalyst. By this approach, the fine chemical MG, the bulk chemical EG, and the fuel additive EtOH can all be efficiently produced from renewable cellulosic materials, thus providing a new pathway towards mitigating the dependence on fossil resources.
Xu, Gang,Wang, Aiqin,Pang, Jifeng,Zhao, Xiaochen,Xu, Jinming,Lei, Nian,Wang, Jia,Zheng, Mingyuan,Yin, Jianzhong,Zhang, Tao
p. 1390 - 1394
(2017/04/14)

Effect of Cu-doping on the structure and performance of molybdenum carbide catalyst for low-temperature hydrogenation of dimethyl oxalate to ethanol
Several copper-doped molybdenum carbide (Cu–Mo2C) nanomaterials for the hydrogenation of dimethyl oxalate (DMO) to ethanol at low temperature (e.g., 473 K) have been developed through a facile solid-state pyrolysis method. Characterization techniques including X-ray diffraction, scanning/transmission electron microscopy, N2-physisorption, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy were employed to reveal the morphology, structure and properties of the synthesized nanomaterials. The characterization and reaction results suggest that the incorporation of copper species in Mo2C plays a crucial role in modifying the morphologic structure of Cu–Mo2C as well as tuning the electronic state of Mo active sites, resulting in an important enhancement in the catalytic performance. Moreover, a strong synergistic effect between Cu and Mo2C is observed in DMO hydrogenation. Accordingly, the 67.2% yield of ethanol can be attained at a low temperature of 473 K over the Cu–Mo2C nanomaterials with a suitable atom ratio (e.g., Cu:Mo = 0.03:1), which are higher than those obtained by using a pure Mo2C (e.g., 13.7%) under the same reaction conditions. The Cu-doped Mo2C nanomaterials also display excellent catalytic stability during the hydrogenation of DMO to ethanol for longer than 300 h.
Liu, Yanting,Ding, Jian,Bi, Jicheng,Sun, Yanping,Zhang, Juan,Liu, Kefeng,Kong, Fanhua,Xiao, Haicheng,Chen, Jiangang
p. 143 - 155
(2016/11/23)

Synergistic Effect of a Boron-Doped Carbon-Nanotube-Supported Cu Catalyst for Selective Hydrogenation of Dimethyl Oxalate to Ethanol
Heteroatom doping is a promising approach to improve the properties of carbon materials for customized applications. Herein, a series of Cu catalysts supported on boron-doped carbon nanotubes (Cu/xB-CNTs) were prepared for the hydrogenation of dimethyl oxalate (DMO) to ethanol. The structure and chemical properties of boron-doped catalysts were characterized by XRD, TEM, N2O pulse adsorption, CO chemisorption, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption, which revealed that doping boron into CNT supports improved the Cu dispersion, strengthened the interaction of Cu species with the CNT support, introduced more surface acid sites, and increased the surface area of Cu0 and especially Cu+ sites. Consequently, the catalytic activity and stability of the catalysts were greatly enhanced by boron doping. 100 % DMO conversion and 78.1 % ethanol selectivity could be achieved over the Cu/1B-CNTs catalyst, the ethanol selectivity of which was almost 1.7 times higher than that of the catalyst without boron doping. These results suggest that doping CNTs with boron is an efficient approach to improve the catalytic performance of CNT-based catalysts for hydrogenation of DMO. The boron-doped CNT-based catalyst with improved ethanol selectivity and catalytic stability will be helpful in the development of efficient Cu catalysts supported on non-silica materials for selective hydrogenation of DMO to ethanol.
Ai, Peipei,Tan, Minghui,Yamane, Noriyuki,Liu, Guoguo,Fan, Ronggang,Yang, Guohui,Yoneyama, Yoshiharu,Yang, Ruiqin,Tsubaki, Noritatsu
supporting information
p. 8252 - 8261
(2017/06/23)

Investigation of Activated-Carbon-Supported Copper Catalysts with Unique Catalytic Performance in the Hydrogenation of Dimethyl Oxalate to Methyl Glycolate
Copper-based activated-carbon (AC)-supported catalysts were synthesized by a facile ammonia evaporation-impregnation method. Unlike the conventional Cu/SiO2 catalyst, which showed highly catalytic selectivity towards ethylene glycol (EG) or EtOH, Cu/AC catalysts display unique selectivity to methyl glycolate (MG). The catalytic performance relies on the high content of surface Cu+ species and the relatively large copper particles with moderate hydrogenation activity.
Cui, Yuanyuan,Wang, Bin,Wen, Chao,Chen, Xi,Dai, Wei-Lin
p. 527 - 531
(2016/02/20)

Copper-Fiber-Structured Pd-Au-CuOx: Preparation and Catalytic Performance in the Vapor-Phase Hydrogenation of Dimethyl Oxalate to Ethylene Glycol
Cu-fiber-structured ternary Pd-Au-CuOx catalysts engineered from nano- to macro-scales have been developed for the vapor-phase dimethyl oxalate (DMO) hydrogenation to ethylene glycol (EG), with the aid of galvanic deposition of Pd and Au onto a thin-sheet microfibrous structure using 8 μm Cu fiber. Effects of Pd and Au loadings and their ratio have been investigated on the catalyst performance as well as the reaction conditions including reaction temperature and pressure, liquid weight hourly space velocity, and H2/DMO ratio. The promising 0.1 Pd-0.5 Au-CuOx/Cu-fiber catalyst is capable of converting 97-99 % DMO into EG product at a selectivity of 90-93 %. This catalyst is stable for at least 200 h. The Pd-Au-Cu2O synergistically promotes the hydrogenation activity and stabilizes Cu+ sites to suppress deep reduction deactivation.
Han, Lupeng,Zhang, Li,Zhao, Guofeng,Chen, Yanfei,Zhang, Qiaofei,Chai, Ruijuan,Liu, Ye,Lu, Yong
p. 1065 - 1073
(2016/04/05)

Synthesis and catalytic performance of ruthenium complexes ligated with rigid: O -(diphenylphosphino)aniline for chemoselective hydrogenation of dimethyl oxalate
A series of new ruthenium complexes with rigid ligand o-(diphenylphosphino)aniline, including [(PPh3)(o-PPh2C6H4NH2)RuCl2]2 (1), (o-PPh2C6H4NH2)2RuCl2 (2), [(o-PPh2C6H4NH2)2(o-PPh2C6H4NH)Ru]+Cl- (3), Ph3P(η2-H2)Ru(μ-H)(μ-o-PPh2C6H4NH)2RuH(PPh3) (4), (o-PPh2C6H4NH2)(o-PPh2C6H4NH)RuCl(CO) (5), (o-PPh2C6H4NH2)(o-PPh2C6H4NH)RuH(CO) (6), and [(o-PPh2C6H4NH)2Ru(CO)]2 (7) were synthesized and employed as catalysts for chemoselective hydrogenation of esters. Among them, complexes 1, 2, and 5 exhibited excellent performance in hydrogenation of dimethyl oxalate to methyl glycolate, in comparison with the ruthenium complexes with a flexible aminophosphine ligand, such as (Ph2P(CH2)2NH2)2RuCl2, (Ph2P(CH2)3NH2)2RuCl2, and (o-Ph2PC6H4CH2NH2)2RuCl2, under identical conditions. Complexes 1 and 2 also displayed good activities in the hydrogenation of other aliphatic and cyclic esters. The catalytic mechanism of hydrogenation was discussed according to the results of NMR spectroscopic studies and control experiments.
Fang, Xiaolong,Zhang, Chunyan,Chen, Jin,Zhu, Hongping,Yuan, Youzhu
p. 45512 - 45518
(2016/06/06)

Efficient hydrogenation of dimethyl oxalate to ethylene glycol: Via nickel stabilized copper catalysts
CuNi/SiO2 nanocatalysts with Ni-stabilized Cu nanoparticles of around 10 nm were synthesized. After H2 reduction, the catalysts with grain size of around 25 nm showed very high performance in the catalytic hydrogenation of dimethyl oxalate to ethylene glycol under mild reaction conditions. The composition and structure of these nanocatalysts were characterized. This study showed that Ni played a key role in stabilizing Cu against deactivation. To meet the requirements of industrial application, the optimal CuNi/SiO2 nanocatalyst was tested under continuous reaction for over 2000 hours. The conversion and product selectivity were maintained at 99% and above 95%, respectively.
Zhu, Junhua,Ye, Yingchun,Tang, Yi,Chen, Liangfeng,Tang, Kangjian
p. 111415 - 111420
(2016/12/07)

Method and catalyst for hydrogenating oxalate to produce methyl glycolate
The invention relates to a method and a catalyst for hydrogenating oxalate to produce methyl glycolate. The problems of low selectivity of glycolate in hydrogenation products and high catalyst cost existing in previous technologies are mainly solved. In the invention, metal copper or an oxide thereof is adopted as an active component, a silica-containing composite oxide, such as SBA-15 and a molecular sieve, is adopted as a carrier, and an appropriate metal or an oxide assistant is added. The structure characteristic of the silicon-containing composite oxide molecular sieve is adopted to highly disperse the active component copper or the oxide thereof, so the reaction conversion rate and the methyl glycolate selectivity are improved; adoption of a precious metal assistant is avoided, so the catalyst cost is reduced; and a high oxalate conversion rate and a high methyl glycolate selectivity are simultaneously realized.
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Paragraph 0020; 0021; 0024; 0025

(2017/03/14)

Efficient hydrogenation of dimethyl oxalate to methyl glycolate over highly active immobilized-ruthenium catalyst
Highly active and stable catalysts for hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) were desirable but highly challengeable. In this study, a kind of immobilized Ru based catalyst for the hydrogenation of DMO has been developed. The catalyst was synthesized by covalently bonding a ruthenium complex onto the modified-SiO2 surface, which was modified by 3-aminopropyltriethoxysilane (KH550), through coordination interaction with aminosilane ligands. Compared with the traditional Ru/SiO2 catalyst, the immobilized Ru-NH2-SiO2 catalyst exhibits significantly enhanced catalytic performance and high stability towards hydrogenation of dimethyl oxalate to MG at temperatures as low as 80?°C. The yield of MG was 86.8% over Ru-NH2-SiO2 catalyst, while the yield of MG was only 34.5% over Ru/SiO2 catalyst. A series of characterization revealed that the excellent catalytic performance of Ru-NH2-SiO2 was resulted from the superior dispersion of Ru NPs on the surface of support and the electron-rich state of Ru centers.
Fan, Hanhan,Tan, Jingjing,Zhu, Yulei,Zheng, Hongyan,Li, Yongwang
p. 68 - 75
(2016/10/04)

A process for production of glycolic acid chloroacetic acid
The invention discloses a process for producing glycollic acid by using monochloro acetic acid. The process comprises a rough maching process of carrying out hydrolysis, concentration, cooling and throwing on monochloro acetic acid and sodium carbonate so as to obtain a crude solid glycollic acid product, The process is characterized in that a fine machining process is further carried out on the basis of the rough machining process, wherein the fine machining process comprises the following steps of: a, mixing the crude solid glycollic acid product with methanol according to a weight ratio of 1:(3-5); b, sufficiently dissolving the mixture at 50-55 DEG C, and holding for 0.3-1 hour; and c, cooling to 1-3 DEG C, throwing the material so as to obtain two substances, namely a solid substance and a liquid substance, wherein the liquid substance is a crude methyl glycolate product and the solid substance is a fine glycollic acid product. The process has the beneficial effects that the chlorine content of the fine glycollic acid product prepared by using the process is 10PPM, so that the limit of raw materials is overcome, the problem of chlorine content is well solved, and meanwhile methyl glycolate with good quality can be produced, so that recycling of energy is facilitated, and remarkable economic and social effects are achieved.
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Paragraph 0028

(2017/02/09)

Ni-containing Cu/SiO2 catalyst for the chemoselective synthesis of ethanol via hydrogenation of dimethyl oxalate
A highly efficient nickel doped Cu/SiO2 catalyst was investigated for the vapor-phase selective hydrogenation of dimethyl oxalate to ethanol. Nickel species were introduced into a silica-supported copper catalyst by an impregnation method. An appropriate amount of Ni significantly enhanced the ability of H2 to adsorb and dissociate on the Cu/SiO2 catalyst. Consequently, the catalytic performance of the catalyst was greatly improved and a selectivity for ethanol of 90% was achieved with the catalyst with 1 wt% Ni. Moreover, the addition of nickel resulted in the formation of Cu–Ni bimetallic nanoparticles and surface segregation occurs in bimetallic nanoparticles. When excessive amount of nickel was introduced into the Cu/SiO2 catalyst, the catalytic performance deteriorated because of serious surface segregation and aggregation of the copper.
Zhao, Yujun,Zhao, Shuo,Geng, Yaochen,Shen, Yongli,Yue, Hairong,Lv, Jing,Wang, Shengping,Ma, Xinbin
p. 28 - 35
(2016/11/23)

Process for the preparation of hydroxy-acetic acid
The invention relates to a preparation method of hydroxyacetic acid. The preparation method comprises the following steps: performing a hydrolysis reaction on an aqueous solution of hydroxynitrile and a sulfuric acid solution having the mass concentration of 70%-90% at a temperature within the range of 120-140 DEG C, thereby obtaining the mixed solution of hydroxyacetic acid and an acidic salt ammonia sulfate; at the same time of performing an esterification reaction by adding methanol to the mixed solution, distilling out the mixture of methanol, water and methyl hydroxylacetate, and controlling the temperature of the whole process within the range of 110-120 DEG C; adding water to adjust the mass percentage of methyl hydroxylacetate in the mixture to the range of 10%-25%, hydrolyzing methyl hydroxylacetate at a temperature less than or equal to 100 DEG C into hydroxyacetic acid, separating out methanol and water, and recycling separated methanol. According to the preparation method, due to the improvement of the reaction temperatures, the raw material concentration and the preparation method, the reaction time is shortened and the energy consumption and the methanol loss are reduced under the premise of guaranteeing the yield; as a result, the production cost is greatly reduced and the product competitiveness is improved.
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Paragraph 0031

(2017/01/02)

Mechanistic insights into the production of methyl lactate by catalytic conversion of carbohydrates on mesoporous Zr-SBA-15
The as-synthesized Zr-SBA-15 catalysts with tunable mesoporous structures showed excellent catalytic performance for the conversion of carbohydrates to methyl lactate in a "one-pot" process using near-critical methanol or methanol-water mixture as the solvents. The effects of reaction conditions, including temperature, reaction time, and catalyst loading amount, on the conversions of carbohydrates and the yields of methyl lactate were investigated. The high yields of methyl lactate, up to 41% and 44%, were produced from pentose and hexose, respectively, in the near-critical methanol at 240 °C. Moreover, the Si/Zr ratio of the Zr-SBA-15 catalysts profoundly affected the Lewis acidity and therefore the catalytic activity and selectivity to methyl lactate in the conversion of carbohydrates. The pore size of the Zr-SBA-15 catalysts, tuned by the synthesis temperature, strongly affected the formation of solid residues. The key intermediates such as glyceraldehyde, glycolaldehyde, and pyruvaldehyde were used as probe reactants to understand the mechanism. The role of the Zr-SBA-15 catalyst in the aldol- and retro-aldol condensation, isomerization, and Cannizzaro reactions of carbohydrates and their derivatives was discussed. Furthermore, 28% and 27% yields of methyl lactate were obtained from cellulose and starch, respectively, in methanol-water mixture (5 wt% water and 95 wt% methanol) at 240 °C. The Zr-SBA-15 catalyst was relatively stable in short term without regeneration.
Yang, Lisha,Yang, Xiaokun,Tian, Elli,Vattipalli, Vivek,Fan, Wei,Lin, Hongfei
p. 207 - 216
(2015/12/04)

An effective and stable Ni2P/TiO2 catalyst for the hydrogenation of dimethyl oxalate to methyl glycolate
An effective and stable bifunctional Ni2P/TiO2 catalyst was proposed for gas-phase hydrogenation of dimethyl oxalate to corresponding alcohols. A 93.0% conversion of DMO with a selectivity of 88.0% to methyl glycolate was observed under 210 °C. Moreover, the catalyst showed an excellent stability which can be performed for 3600 h under the reaction conditions of 230 °C, 3 MPa H2 and the weight space velocity of 0.1 h?1.
Chen, Hongmei,Tan, Jingjing,Zhu, Yulei,Li, Yongwang
p. 46 - 49
(2015/10/28)

Natural preservatives
In the present invention, provided is a compound, which has good antibacterial effects and is denoted by general formula (I), or a pharmaceutical acceptable salt thereof where R1 is saturated or unsaturated straight chains or branch chains of an alkyl group in general formula (I); R2 is hydrogen, methyl or is selected from a general formula (2); and R3 is hydrogen, saturated or unsaturated straight chains or branch chains of an alkyl group, and X is hydrogen or is selected from a hydroxyl group in general formula (2).COPYRIGHT KIPO 2015
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Paragraph 0049; 0050

(2016/12/26)

Enhanced chemoselective hydrogenation of dimethyl oxalate to methyl glycolate over bimetallic Ag-Ni/SBA-15 catalysts
Mesoporous silica SBA-15-supported bimetallic silver-nickel catalysts (Ag-Ni/SBA-15) were prepared by a co-impregnation method for the chemoselective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG). The structure and physicochemical properties of the catalysts were characterized using N2 adsorption-desorption, X-ray fluorescence spectroscopy, transmission electron microscopy, H2erature-programmed reduction, UV-vis light diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, fourier-transform infrared spectroscopy and ester temperature-programed desorption. Compared with monometallic Ag or Ni catalyst, the bimetallic Ag-Ni/SBA-15 catalysts exhibited enhanced catalytic performance for the chemoselective hydrogenation of DMO to MG. The optimized Ag-Ni/SBA-15 catalyst with a Ni/Ag atomic ratio of 0.2 presented the highest MG yield and excellent catalytic stability during the hydrogenation of DMO to MG for longer than 140 h. The characterization results suggested that the Ag and Ni bimetallic nanoparticles on the catalyst surfaces likely formed a segregation structure with more Ni species in the core and more Ag in the shell, and electron transfer from Ni to Ag possibly occurred. The interactions between the Ag and Ni species generated more active/adsorption sites and prevented the transmigration of bimetallic nanoparticles during hydrogenation.
Zhou, Junfu,Duan, Xinping,Ye, Linmin,Zheng, Jianwei,Li, Molly Meng-Jung,Tsang, S.C. Edman,Yuan, Youzhu
p. 344 - 353
(2015/09/07)

Heteropolyacids as efficient catalysts for the synthesis of precursors to ethylene glycol by the liquid-phase carbonylation of dimethoxymethane
Methyl methoxyacetate (MMAc), a precursor to ethylene glycol (EG), was synthesized successfully via the liquid-phase carbonylation of dimethoxymethane (DMM) catalyzed by heteropolyacids (HPAs). The experiment results showed that H3PW12O40 (PW12) exhibited the best catalytic performance for the carbonylation of DMM, and its high catalytic activity was attributed to the synergistic effect between its superior acidic strength and the high polarity of the solvent.
Wang, Junpeng,Liu, Jianhua,Song, Heyuan,Chen, Jing
p. 806 - 808
(2015/06/22)

Structured Pd-Au/Cu-fiber catalyst for gas-phase hydrogenolysis of dimethyl oxalate to ethylene glycol
Galvanic co-deposition of 0.5 wt% Au and 0.1 wt% Pd on a microfibrous-structure using 8 μm Cu-fibers delivers a Pd-Au/Cu-fiber catalyst, which is highly active, selective and stable for the hydrogenolysis of dimethyl oxalate to ethylene glycol. Au and Pd synergistically promote the hydrogenolysis activity of Cu+ sites, while Au also critically stabilizes Cu+ sites to prevent deep reductive deactivation.
Zhang, Li,Han, Lupeng,Zhao, Guofeng,Chai, Ruijuan,Zhang, Qiaofei,Liu, Ye,Lu, Yong
supporting information
p. 10547 - 10550
(2015/06/25)

Synthesis and application of glycolic esters in methanol-gasoline as bifunctional additives
Summary : To explore new and multifunctional additives for methanol-gasoline, glycolic esters were synthesized and screened as phase stabilizer and saturation vapor pressure depressor. The effect of the esters' structure on the efficiency was discussed. It was found that the stability of the blends depend on the length of the glycolic esters' alkoxy group, and hexyl glycolic and octyl glycolic were found to be the most effective in various gasoline-methanol blends. Additionally, the glycolic esters can depress the saturation vapor pressure of methanol-gasoline effectively as well, and decyl glycolic is the most effective one. With these data, it can be concluded that the glycolic esters have the great potential to be used as bifunctional gasoline-methanol additives.
Tang, Ying,Cheng, Qitong,Zhang, Jie,Yang, Changchun,Wang, Shanshan,Wang, Xiaoli,Zhao, Zhen
p. 1109 - 1113
(2015/01/30)

Promoted role of Cu(NO3)2 on aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over VOSO4
The promoted effect of Cu(NO3)2 on aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) catalyzed by VOSO4 in acetonitrile was intensively investigated. It was revealed that Cu(NO3)2 facilitated the activation of VOSO 4 to generate active V5+ species via the generation of NOx gas. The high DFF selectivity is ascribed to Cu2+ cation which can effectively prohibit oxidative CC bond cleavage reaction of HMF and prevent radical reaction of DFF to humins. In addition, the polarity of solvent plays a great role on high selectivity of DFF.
Jia, Xiuquan,Ma, Jiping,Wang, Min,Du, Zhongtian,Lu, Fang,Wang, Feng,Xu, Jie
p. 231 - 236
(2014/07/08)

Investigation of the structural evolution and catalytic performance of the CuZnAl catalysts in the hydrogenation of dimethyl oxalate to ethylene glycol
A series of CuZnAl catalysts are synthesized and investigated to study the catalytic performance in the gas-phase hydrogenation of dimethyl oxalate to ethylene glycol. The catalytic activity increases with the increasing of the copper loading, but much higher copper content in the catalysts will lead to the aggregation of the copper particles and cause the deactivation of the catalysts. The influence of calcination temperature is also investigated to probe the microstructure evolution of the catalysts. The catalysts calcinated at low temperature display weak metal-support interaction with poor reducibility and exhibit poor catalytic activity. When the calcination temperature was risen up to temperature higher than 873 K, the mesoporous structure of the support is collapsed or sintered which further lead to the low dispersion of the copper species and poor catalytic property. The catalyst with molar ratio of copper: zinc: aluminium as 1/4/5 (CZA1-4-5) calcinated at 773 K shows the best catalytic performance and can keep the high activity for more than 200 h of time on stream, both the conversion and the selectivity to EG still remain unchanged.
Wen, Chao,Li, Fanqi,Cui, Yuanyuan,Dai, Wei-Lin,Fan, Kangnian
p. 117 - 126
(2014/07/07)

A continuous process for glyoxal valorisation using tailored Lewis-acid zeolite catalysts
The aqueous-phase heterogeneously catalysed isomerisation of bio-oil derived glyoxal is herein introduced as a novel route for the sustainable production of glycolic acid. While commercial ultra-stable Y zeolites displayed only moderate performance, their evaluation enabled us to highlight the crucial role of Lewis acidity in the reaction. Gallium incorporation into these zeolites boosted the glycolic acid yield, although the best catalytic results were obtained over tin-containing MFI-type zeolites, reaching 91% yield of the desired product at full conversion. These materials comprised hydrothermally-synthesised Sn-MFI as well as a novel catalyst obtained by the introduction of tin into silicalite-1 by means of a simpler and more scalable method, i.e. alkaline-assisted metallation. In-depth spectroscopic characterisation of these systems uncovered a substantial similarity of the tin centres obtained by the top-down and bottom-up synthetic approaches. NMR spectroscopic studies gave evidence that the reaction follows a 1,2-hydride shift mechanism solely catalysed by Lewis-acid sites. The Sn-MFI analogue could be reused in 5 cycles without the need for intermediate calcination, did not evidence any tin leaching, and demonstrated suitability for utilisation under continuous-flow operation. The tin-based zeolites exhibited remarkable performance also in alcoholic solvents, leading to the one-pot production of relevant alkyl glycolates.
Dapsens, Pierre Y.,Mondelli, Cecilia,Kusema, Bright T.,Verel, Rene,Perez-Ramirez, Javier
p. 1176 - 1186
(2014/03/21)

Novel functional ionic liquids as metal-free, efficient and recyclable catalysts for the carbonylation of formaldehyde
Methyl glycolate (MG) was synthesized as a precursor to ethylene glycol from the catalytic carbonylation of formaldehyde followed by esterification with methanol by using metal-free, efficient and recyclable SO3H- functionalized ionic liquids (BAILs) as catalysts. Among the studied BAILs, N-butyl-N-(3-sulfonylpropyl) thiomorpholine-1,1-dioxide triflate showed excellent activity and MG selectivity. The effects of reaction parameters such as reactant, solvent, catalyst loading, molar ratio of H2O to H 2CO, temperature, pressure, and reaction time were studied. MG was obtained in high yield under mild conditions. At 160 C, 5.0 MPa, and reactant mole ratio of BAIL:H2CO:H2O = l:40:80, 98 % conversion of formaldehyde was achieved with 94 % selectivities of MG. Catalysts did not show any significant deterioration in performance in repeated use up to eight batches. Graphical Abstract: Methyl glycolate (MG) was synthesized from the carbonylation of formaldehyde followed by esterification with methanol using metal-free, efficient and recyclable SO3H-functionalized ionic liquids (BAILs) as catalysts. MG was obtained in excellent yield under mild conditions. The catalyst was reused up to eight consecutive recycles without apparent loss in its catalytic activity. [Figure not available: see fulltext.]
Song, Heyuan,Jing, Fuxiang,Jin, Ronghua,Li, Zhen,Chen, Jing
p. 711 - 716
(2014/04/03)