- Two-Step Continuous-Flow Synthesis of Fungicide Metalaxyl through Catalytic C?N Bond-Formation Processes
-
Metalaxyl, an acylalanine fungicide, was synthesized through catalytic continuous sequential-flow reactions. Commonly used syntheses of this compound use batch systems and suffer from problems such as coproduction of halogen-containing by-products derived from acyl and alkyl halides in the substitution reactions of 2,6-dimethylaniline. To minimize waste and enhance efficiency, a halide-free approach including two continuous-flow catalytic processes, heterogeneous Pt-catalyzed reductive alkylation and homogeneous acid-catalyzed amidation with an acid anhydride, was developed. Systematic examination of the two reactions in flow mode enabled a high-yielding, two-step sequential continuous-flow process to be achieved. (Figure presented.).
- Ishitani, Haruro,Yu, Zhibo,Ichitsuka, Tomohiro,Koumura, Nagatoshi,Onozawa, Shun-ya,Sato, Kazuhiko,Kobayashi, Shū
-
supporting information
p. 18 - 23
(2021/09/02)
-
- Compound with litchi fragrance, preparation method of compound and daily essence
-
The invention relates to the field of spices, in particular to a compound with litchi fragrance, a preparation method of the compound and daily essence. The invention discloses a compound with litchi fragrance. The compound has a structure as shown in a formula (I). Research finds that the compound with litchi fragrance has obvious litchi fragrance, the fragrance intensity is high, and the fragrance is stable and lasting. The invention also provides a preparation method of the compound with litchi fragrance. The raw materials for preparing the compound with litchi fragrance are easy to obtain, the operation is simple, and the compound is suitable for wide popularization and application. The invention further provides a daily essence containing the compound with litchi fragrance.
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Paragraph 0059-0064; 0080-0081; 0085-0086
(2021/05/12)
-
- Enhancing Effect of Residual Capping Agents in Heterogeneous Enantioselective Hydrogenation of α-keto Esters over Polymer-Capped Pt/Al2O3
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Heterogeneous enantioselective catalysis is considered a promising strategy for the large-scale production of enantiopure chemicals. In this work, polymer-capped Pt nanocatalysts having a uniform size were synthesized using poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) and supported on γ-Al2O3. After a facile heat treatment process, their catalytic performance for enantioselective hydrogenation of α-keto esters, a structure-sensitive reaction, was investigated. The presence of residual capping agents on the Pt surface often perturbs the adsorption of reacting species and reduces performance in structure-sensitive reactions. However, the 1 wt % PVP-Pt/Al2O3 catalyst exhibited an enhancement in both activity and enantioselectivity compared to a reference Pt/Al2O3 catalyst prepared by wet impregnation. Under optimized reaction conditions, the cinchonidine-modified PVP-Pt/Al2O3 gave an enantiomeric excess of 95% for the enantioselective hydrogenation of methyl pyruvate despite the low Pt loading. We demonstrate that depending on the type of polymers, the residual capping agents can lead to site-selective blockage of the Pt surface, that is, defects or terraces. Quantitative and qualitative analyses also show that the noticeable improvement in enantioselectivity is attributed to the stable adsorption of chiral modifiers on selectively exposed Pt terrace sites. The findings of this work provide a promising strategy to prepare metal nanoparticles having selectively exposed sites and offer insights into the enhancing effect of residual capping agents on the catalytic properties in structure-sensitive reactions.
- Chung, Iljun,Song, Byeongju,Kim, Jeongmyeong,Yun, Yongju
-
-
- Method for preparing methyl lactate through catalytic conversion of carbohydrate
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The invention discloses a method for preparing methyl lactate through catalytic conversion of carbohydrate. According to the method, an A-SCM-1 molecular sieve is used as a catalyst, a substrate carbohydrate is mixed with methanol, and methyl lactate is obtained through a one-step catalytic reaction. According to the method, efficient conversion of carbohydrate can be realized under mild reaction conditions, the selectivity of the product methyl lactate is high, and the catalyst has outstanding cycling stability and has a good industrial application prospect.
- -
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Paragraph 0078-0079; 0095-0096
(2022/01/04)
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- Conversion of sugars to methyl lactate with exfoliated layered stannosilicate UZAR-S4
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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
-
-
- Method for preparing lactate
-
The invention relates to a method for preparing lactate. The method comprises the following steps: contacting pyruvic aldehyde and alcohol with a catalyst in a reactor, and reacting to obtain a lactate-containing product, wherein the molar ratio of the pyruvic aldehyde to the alcohol is 1:(20-225), the reaction temperature is 30-180 DEG C, the reaction time is 1-10 hours, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of the pyruvic aldehyde to the mixture of the titanium-silicon molecular sieve and the tin-siliconmolecular sieve based on dry basis weight is 1:(0.1-6). The method provided by the invention has high pyruvic aldehyde conversion rate and high lactate yield.
- -
-
Paragraph 0070-0083; 0092-0101
(2020/06/30)
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- Method for preparing lactate by catalyzing pyruvic aldehyde
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The invention relates to a method for preparing lactate by catalyzing pyruvic aldehyde. The method comprises the following steps: contacting pyruvic aldehyde and alcohol with a catalyst in a reactor,and reacting to obtain a lactate-containing product, wherein the molar ratio of pyruvic aldehyde to alcohol is 1:(50-225), the reaction temperature is 30-180 DEG C, the reaction time is 1-10 h, the reaction pressure is 0.1-3 MPa, the catalyst contains a tin-titanium-silicon molecular sieve, and the weight ratio of pyruvic aldehyde to the tin-titanium-silicon molecular sieve based on dry basis weight is 1:(1-6). According to the method, the catalyst containing the binary tin-titanium-silicon molecular sieve is adopted, framework tin atoms and framework titanium atoms of the molecular sieve synergistically catalyze pyruvic aldehyde and alcohol to generate lactate, and the reaction efficiency is improved.
- -
-
Paragraph 0163-0188; 0197-0204; 0210
(2020/07/02)
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- Synergetic effect of Lewis acid and base in modified Sn-β on the direct conversion of levoglucosan to lactic acid
-
This work presents a novel method to selectively convert levoglucosan to lactic acid (LA) via initially adding LA as the Br?nsted acid together with modified Sn-β as the Lewis acid. Sn-β catalysts exchanged with various cations significantly enhance the yield of LA, following the order Sn-β 2+ and Mg2+ appears to be more effective in promoting the retro-aldol condensation due to the synergetic effect of their stronger Lewis acid that can stabilize the oxygen atom of deprotonated alkoxides during the reaction. The LA yield from levoglucosan can reach up to 66% on Sn-β-Ca under the optimized conditions. We also demonstrated that such a synergetic effect of alkaline-earth ion exchanged Sn-β shows great universality toward enhanced retro-aldol condensation, which can significantly promote the yield of methyl lactate over glucose conversion in methanol solvent.
- Chi, Zixin,Hu, Wenda,Lin, Jingdong,Wan, Shaolong,Wan, Yan,Wang, Shuai,Wang, Yong
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p. 2986 - 2993
(2020/06/17)
-
- Promotion effect of Mg on a post-synthesized Sn-Beta zeolite for the conversion of glucose to methyl lactate
-
Mg-Sn-Beta zeolites with different Mg/Sn molar ratios were prepared from the parent deAl-Beta by a coimpregnation method. The samples were characterized by powder X-ray diffraction (XRD), N2 physisorption, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy of the -OH region and probe molecule (pyridine, CD3CN and CHCl3) adsorption. The results indicate that Mg2+ and Sn4+ can react with silanol nests and incorporate into the framework of Beta zeolite. Moreover, it is relatively facile to incorporate Sn4+ into the framework. The framework metal sites generate Lewis (L) acid sites; however, the L acid strength of the framework Mg2+ is weaker than that of framework Sn4+. A small amount of Mg2+ interacts with isolated silanols to form extraframework species. Therefore, the introduction of Mg2+ results in a significant reduction in silanol defects and an increase in L acidity/basicity of Mg-Sn-Beta. Mg-Sn-Beta with Mg/Sn molar ratio of 1 has the least silanol defects. In the conversion of glucose to methyl lactate (MLA), Mg-Beta is less active than Sn-Beta due to its weaker L acidity. The TOF value for MLA formation increased in the order of Sn-Beta 0.25Mg-Sn-Beta ≈ 4Mg-Sn-Beta 1Mg-Sn-Beta, which is closely related to the amount of silanol defects in the catalysts. A kinetic study indicates that the apparent activation energy of the retro-aldol of fructose to MLA, which is the rate-determining step of glucose conversion to MLA, decreases over Mg-Sn-Beta compared to that over Sn-Beta and thus, the formation of MLA was promoted.
- Yang, Xiaomei,Lv, Bin,Lu, Tianliang,Su, Yunlai,Zhou, Lipeng
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p. 700 - 709
(2020/02/27)
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- Bi-Functional Magnesium Silicate Catalyzed Glucose and Furfural Transformations to Renewable Chemicals
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Bio-refinery is attracting significant interest to produce a wide range of renewable chemicals and fuels from biomass that are alternative to fossil fuel derived petrochemicals. Similar to petrochemical industries, bio-refinery also depends on solid zeolite catalysts. Acid-base catalysis plays pivotal role in producing a wide range of chemicals from biomass. Herein, the Mg framework substituted MTW zeolite is synthesized and explored in the valorisation of glucose and furfural. Bi-functional (acidic and basic) characteristics are confirmed using pyridine adsorbed FT?IR analysis and NH3 and CO2 temperature-programmed desorption techniques. Textural properties and morphological information are retrieved from N2-sorption, X-ray photoelectron spectroscopy, and electron microscopy. The activity of the catalyst is demonstrated in the selective isomerisation of glucose to fructose in ethanol. Glucose is converted to methyl lactate in high yield using the same catalyst. Further, the bi-functional activity of this catalyst is demonstrated in the production of fuel precursor by the reaction of furfural and isopropanol. Mg?MTW zeolite exhibits excellent activity in the production of all these chemicals and fuel derivative. The catalyst exhibits no significant loss in the activity even after five recycles. One simple catalyst affording three renewable synthetic intermediates from glucose and furfural will attract significant attention to catalysis researchers and industrialists.
- Kumar, Abhinav,Srivastava, Rajendra
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p. 4807 - 4816
(2020/08/24)
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- Method for preparing lactate
-
The invention relates to a method for preparing lactate. The method comprises the following steps of: contacting sugar and alcohol with a catalyst in a reactor, and reacting to obtain a lactate-containing product, wherein the molar ratio of the sugar to the alcohol is 1:(50-900), the reaction temperature is 150-250 DEG C, the reaction time is 10-50 hours, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of the sugar to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve based on drybasis weight is 1:(0.1-6). The method provided by the invention has high sugar conversion rate and high lactate yield.
- -
-
Paragraph 0070-0083; 0092-0101
(2020/06/30)
-
- Conversion of Dihydroxyacetone to Methyl Pyruvate Catalyzed by Hybrid Molecular Sieves at Low Temperature: A Strategy for the Green Utilization of Glycerol
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Abstract: Methyl pyruvate (MPA) was synthesized from dihydroxyacetone (DHA), the oxidation product of glycerol, over Sn-β and TS-1 hybrid molecular sieves at low temperature. Sn-β and TS-1 provide the active sites for conversion of DHA to methyl lactate (MLA) and oxidation of MLA to MPA, respectively. Synergism of Lewis acid sites on Sn-β and TS-1 realize the production of MPA from DHA. After optimization, 71% yield of MPA can be obtained under 50?°C. This is the first report for the synthesis of MPA from DHA directly. Graphic Abstract: [Figure not available: see fulltext.].
- Luo, Qianqian,Lu, Tianliang,Xu, Jun,Yang, Xiaomei,Zhou, Lipeng
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p. 1641 - 1649
(2019/12/24)
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- 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
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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.
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p. 4115 - 4126
(2019/08/12)
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- Production of lactic acid derivatives from sugars over post-synthesized Sn-Beta zeolite promoted by WO3
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Various metal oxides were used as co-catalysts to improve the production of alkyl lactate over Sn-Beta-P. WO3 exhibited the best promotion effect. The yield of MLA increased from 25% (6.5 g L?1) over Sn-Beta-P (0.2 g) to 52% (13.4 g L?1) over WO3 (0.1 g) and Sn-Beta-P (0.1 g) at 160 °C for 5 h and 3.1 wt% of glucose concentration. MLA yield of 38% was attained even at glucose concentration of 10 wt% and the space-time yield reached 7.1 g L?1 h?1. The action mechanism of WO3 was investigated. Fine WO3 particles adsorbed on surface of Sn-Beta-P in reaction media and decreased the silanol defects of Sn-Beta-P. This promotes retro-aldol of fructose, the rate-determining step of whole reaction, thus facilitated the formation of MLA. Kinetic studies indicate that the presence of WO3 decreased the activation energy of the retro-aldol of fructose. The binary solid WO3 and Sn-Beta-P is recyclable.
- Yang, Xiaomei,Zhang, Yali,Zhou, Lipeng,Gao, Beibei,Lu, Tianliang,Su, Yunlai,Xu, Jie
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p. 285 - 291
(2019/03/21)
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- Tin-Carboxylate MOFs for Sugar Transformation into Methyl Lactate
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With the purpose of improving the production of methyl lactate (ML) from sugars (glucose and sucrose), a new metal-organic framework (MOF) denoted as UZAR-S10, containing Sn ions and ligand 2-aminobenzene-1,4-dicarboxylate was synthesized. The SEM and PXRD characterization revealed that UZAR-S10 was highly crystalline. The empirical formula of UZAR-S10 is [(NH2-BDC)Sn]·(NH2-BDC)0.5, i.e., per Sn atom, with one structural ligand molecule and half ligand molecule trapped in the MOF structure. The removal of the trapped ligand by either solvent extraction or thermal treatment damaged the structure of UZAR-S10, not enabling its activation. The performance of UZAR-S10 in the production of ML was compared to those achieved with different types of carboxylate MOFs, especially with that of Sn partially substituted Ti tetracarboxylate MOF denoted MIP-177-LT (MIP-177-LT(Ti/Sn)). The highest ML yields achieved from sucrose were 29.5 % and 42.0 % for UZAR-S10 and MIP-177-LT(Ti/Sn), respectively. For comparison, other carboxylate type MOFs (MIL-53(Al), NH2-MIL-53(Al), UiO-66, MIL-101(Cr) and HKUST-1) were tested at the same conditions with worse performance than the two Tin-containing MOFs.
- Murillo, Beatriz,Zornoza, Beatriz,de la Iglesia, Oscar,Wang, Sujing,Serre, Christian,Téllez, Carlos,Coronas, Joaquín
-
supporting information
(2019/06/13)
-
- 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)
-
- Method for directly preparing lactate from 1,2-propanediol and short-chain alkyl alcohols
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The invention belongs to the technical field of organic matter synthesis, and particularly relates to a method for directly preparing lactate from 1,2-propanediol and short-chain alkyl alcohols, and the method comprises the following steps: using a sodium stannate loaded rare noble metal as a catalyst, adding C1-C4 alkyl alcohols and the 1,2-propanediol into a high-pressure reaction kettle, usingnitrogen for purging air in the kettle, heating and stirring while the temperature is maintained to promote esterification of the 1,2-propanediol with the C1-C4 alkyl alcohols after oxidation of the 1,2-propanediol to produce the lactate. The method has mild reaction conditions and simple reaction steps, the 1,2-propanediol is completely converted, and the highest selectivity of the lactate can reach 78%. Meanwhile, the synthesized sodium stannate loaded rare noble metal has high catalytic activity and reusability.
- -
-
Paragraph 0032; 0037-0038; 0041-0042; 0045
(2019/10/15)
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- Confinement of Ultrasmall Cobalt Oxide Clusters within Silicalite-1 Crystals for Efficient Conversion of Fructose into Methyl Lactate
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Chemocatalysis of sugars to methyl lactate (MLA) exhibits great advantages over the conventional fermentation approach because of its higher productivity and cost-effective separation process. However, widely used supported metal oxide catalysts suffer from deactivation resulting from sintering during the reaction and removal of coke at high temperatures. Herein, we report ultrasmall cobalt oxide clusters (~1.7 nm) stabilized within silicalite-1 crystals catalyst (CoO@silicalite-1), exhibiting superior catalytic activity and resistance to sintering for the conversion of fructose into methyl lactate. HAADF-STEM, EDS-mapping, and XRD experiments identify the existence of confined CoO clusters. XANES and Raman spectra demonstrated the covalent interaction between CoO and silicalite-1. Thanks to the ultrasmall CoO particle size (~1.7 nm), the CoO@silicalite-1 affords nearly 100-fold higher Co-mass-based activity (mg MLA/mg Co) compared with CoO or Co3O4 particles outside the silicalite-1 framework. More importantly, this catalyst exhibits good reuse performance via the removal of coke with facile calcination.
- Yan, Yue,Zhang, Zihao,Bak, Seong-Min,Yao, Siyu,Hu, Xiaobing,Shadike, Zulipiya,Do-Thanh, Chi-Linh,Zhang, Feng,Chen, Hao,Lyu, Xilei,Chen, Kequan,Zhu, Yimei,Lu, Xiuyang,Ouyang, Pingkai,Fu, Jie,Dai, Sheng
-
p. 1923 - 1930
(2019/03/08)
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- Synergistic Production of Methyl Lactate from Carbohydrates Using an Ionic Liquid Functionalized Sn-Containing Catalyst
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Considerable progress has been made recently in the catalytic conversion of renewable biomass resources to methyl lactate (MLA). However, conceiving eco-friendly and effective catalytic systems for the production of MLA from biomass carbohydrates remains a key challenge. Herein, we report a multifunctional catalyst Sn(salen)/IL, consisting of a Sn(salen) complex and an imidazolium-based ionic liquid (IL), which acts via an intramolecular synergistic effect to convert carbohydrates to MLA in methanol. The versatile properties of the resultant catalyst were revealed to be responsible for the conversion of fructose to MLA and the efficient suppression of undesired side reactions. This catalyst displayed outstanding catalytic activity, high selectivity, and excellent recyclability, giving an MLA yield of up to 68.9 % at 160 °C after 2 h. The results of this study will contribute to new approaches for designing synergistic catalysts for producing liquid fuels and chemicals from biomass resources.
- Wang, Fenfen,Wen, Yi,Fang, Yanxiong,Ji, Hongbing
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p. 4154 - 4161
(2018/09/06)
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- Application of tungsten-based solid acid in lactic acid and lactate preparation using biomass and saccharides
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The invention relates to the technical field of chemical catalyzing, in particular to application of tungsten-based solid acid in lactic acid and lactate preparation using biomass and saccharides. Tungsten-containing salt is allowed to have hydro-thermal synthesis reaction with the chlorine salt, sulfate, nitrate, phosphate and oxalate of barium, calcium, lead, aluminum, chromium, erbium, tin, germanium, niobium and tantalum to prepare a multiple-component tungsten-based solid acid catalyst. The multiple-component tungsten-based solid acid catalyst is simple to prepare, cheap, good in hydrothermal stability, easy to recycle, capable of catalyzing monosaccharides such as fructose and glucose to convert into the lactic acid or lactate, capable of catalyzing polysaccharides such as sucrose, maltose, starch and cellulose even biomass such as wood and corn straw containing cellulose to have hydrolysis reaction so as to prepare the lactic acid or lactate, promising in application prospect and the like, multi-step reaction catalyzing by one single catalyst is achieved, and the range of the biomass and the saccharides which can be converted by the catalyst is wide.
- -
-
Paragraph 0026; 0028
(2018/11/03)
-
- Photoiodocarboxylation of Activated C=C Double Bonds with CO2 and Lithium Iodide
-
The photolysis at 254 nm of lithium iodide and olefins 1 carrying an electron-withdrawing Z-substituent in CO2-saturated (1 bar) anhydrous acetonitrile at room temperature produces the atom efficient and transition metal-free photoiodocarboxylation of the C=C double bond. The reaction proceeds well for terminal olefins 1 to form the new C-I and C-C σ-bonds at the α and β-positions of the Z-substituent, respectively, and is strongly inhibited by polar protic solvents or additives. The experimental results suggest that the reaction channels through the radical anion [CO2?-] in acetonitrile, yet involves different intermediates in aqueous medium. The stabilizing ion-quadrupole and electron donor-acceptor interactions of CO2 with the iodide anion play a crucial role in the reaction course as they allow CO2 to penetrate the solvation shell of the anion in acetonitrile, but not in water. The reaction paths and the reactive intermediates involved under different conditions are discussed.
- Mello, Rossella,Arango-Daza, Juan Camilo,Varea, Teresa,González-Nú?ez, María Elena
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p. 13381 - 13394
(2018/11/20)
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- Kinetic analysis of hexose conversion to methyl lactate by Sn-Beta: Effects of substrate masking and of water
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Simple sugars show promise as substrates for the formation of fuels and chemicals using heterogeneous catalysts in alcoholic solvents. Sn-Beta is a particularly well-suited catalyst for the cleavage, isomerization and dehydration of sugars into more valuable chemicals. In order to understand these processes and save resources and time by optimising them, kinetic and mechanistic analyses are helpful. Herein, we study substrate entry into the Sn-Beta-catalysed methyl lactate process using abundant hexose substrates. NMR spectroscopy is applied to show that the formation of methyl lactate occurs in two kinetic regimes for fructose, glucose and sucrose. The majority of methyl lactate is not formed from the substrate directly, but from methyl fructosides in a slow regime. At 160 °C, more than 40% of substrate carbon are masked (i.e. reversibly protected in situ) as methyl fructosides within a few minutes when using hydrothermally synthesised Sn-Beta, while more than 60% methyl fructosides can be produced within a few minutes using post-synthetically treated Sn-Beta. A significant fraction of the substrate is thus masked by rapid methyl fructoside formation prior to subsequent slow release of fructose. This release is the rate-limiting step in the Sn-Beta-catalysed methyl lactate process, but it can be accelerated by the addition of small amounts of water at the expense of the maximum methyl lactate yield.
- Tosi, Irene,Riisager, Anders,Taarning, Esben,Jensen, Pernille Rose,Meier, Sebastian
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p. 2137 - 2145
(2018/05/04)
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- METHOD FOR PRODUCING LACTIC ACID USING TIN COMPOUND AND SULFONIC ACID OR SULFURIC ACID
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PROBLEM TO BE SOLVED: To inexpensively provide a method for producing lactic acid or its ester from a carbohydrate-containing raw material at a high yield. SOLUTION: Provided is a method for producing lactic acid or its ester containing a process where a hydrocarbon-containing raw material is heated in the presence of a tin (IV) compound having two or more hydrocarbon groups and sulfonic acid or sulfuric acid, and reaction is caused. Also provided is a method for producing lactic acid or its ester capable of improving the yield of lactic acid or its ester by jointly using a fluorine-containing alt, boric acid or organic boric acid as an additive. Further, the reaction is performed in a solvent containing water and/or alcohol in the presence of a fluorine-containing salt, boric acid, organic boric acid or their mixture. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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-
Paragraph 0032; 0035-0042
(2018/05/08)
-
- Effects of Alkali-Metal Ions and Counter Ions in Sn-Beta-Catalyzed Carbohydrate Conversion
-
Alkali-metal ions have recently been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali-metal ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure and are herein addressed experimentally through kinetic experiments and isotope tracking. The presence of alkali-metal ions has a differential effect in competing reaction pathways and promotes the rate of carbon–carbon bond breakage of carbohydrate substrates, but decreases the rates of competing dehydration pathways. Further addition of alkali-metal ions inhibits the activity of Sn-Beta in all major reaction pathways. The alkali-metal effects on product distribution and on the rate of product formation are similar, thus pointing to a kinetic reaction control and to irreversible reaction steps in the main pathways. Additionally, an effect of the accompanying basic anions is shown, supposedly facilitating the cation exchange and eliciting a different concentration-dependent effect to that of neutral alkali-metal salts.
- Elliot, Samuel G.,Tolborg, S?ren,Madsen, Robert,Taarning, Esben,Meier, Sebastian
-
p. 1198 - 1203
(2018/03/21)
-
- Quantitative NMR Approach to Optimize the Formation of Chemical Building Blocks from Abundant Carbohydrates
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The future role of biomass-derived chemicals relies on the formation of diverse functional monomers in high yields from carbohydrates. Recently, it has become clear that a series of α-hydroxy acids, esters, and lactones can be formed from carbohydrates in alcohol and water solvents using tin-containing catalysts such as Sn-Beta. These compounds are potential building blocks for polyesters bearing additional olefin and alcohol functionalities. An NMR approach was used to identify, quantify, and optimize the formation of these building blocks in the Sn-Beta-catalyzed transformation of abundant carbohydrates. Record yields of the target molecules can be achieved by obstructing competing reactions through solvent selection.
- Elliot, Samuel G.,Tolborg, S?ren,Sádaba, Irantzu,Taarning, Esben,Meier, Sebastian
-
p. 2990 - 2996
(2017/07/25)
-
- PRODUCTION OF ALPHA-HYDROXY CARBOXYLIC AIDS AND ESTERS FROM HIGHER SUGARS USING TANDEM CATALYST SYSTEMS
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The present disclosure is directed to methods and composition used in the preparation of alpha-hydroxy carboxylic acids and esters from higher sugars using a tandem catalyst system comprising retro-aldol catalysts and Lewis acid catalysts. In some embodiments, these alpha-hydroxy carboxylic acids may be prepared from pentoses and hexoses. The retro-aldol and Lewis catalysts may be characterized by their respective ability to catalyze a 1,2-carbon shift reaction and a 1,2-hydride shift reaction on an aldose or ketose substrate.
- -
-
Page/Page column 13-14
(2017/02/09)
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- Fluoride-free and low concentration template synthesis of hierarchical Sn-Beta zeolites: Efficient catalysts for conversion of glucose to alkyl lactate
-
Hierarchical Sn-Beta zeolite was prepared through a hydrothermal postsynthesis method, which employed no fluoride and only a small amount of tetraethyl ammonium hydroxide (TEAOH). The dual roles of TEAOH as a base and as a structure directing agent were discussed in detail, which were significantly affected by its concentration. At a TEAOH concentration of 0.2-0.4 mol L-1, hierarchical Sn-Beta zeolites with the most probable mesopore diameter of 7.8 nm were achieved. Other physicochemical properties of the hierarchical Sn-Beta including the content and state of Sn and the acidity were also characterized. The hierarchical Sn-Beta zeolite gave a higher yield of methyl lactate (58%) than the microporous Sn-Beta zeolite synthesized in fluoride medium (47%) due to the promoting effect of the hierarchical porosity on the conversion of glucose in methanol, which is an important and challenging process of a biorefinery. The hierarchical Sn-Beta zeolite is stable and can be recycled and reused five times without significant loss of activity and selectivity.
- Yang, Xiaomei,Bian, Jingjing,Huang, Jianhao,Xin, Weiwen,Lu, Tianliang,Chen, Chen,Su, Yunlai,Zhou, Lipeng,Wang, Feng,Xu, Jie
-
p. 692 - 701
(2017/08/14)
-
- Direct conversion of cellulose to high-yield methyl lactate over Ga-doped Zn/H-nanozeolite Y catalysts in supercritical methanol
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For realizing sustainable bio-based refineries, it is crucial to obtain high yields of value-added chemicals via the direct conversion of cellulose and lignocellulosic biomass. Although the conversion of cellulose using homogeneous catalysts has been demonstrated to be quite successful, low cellulose conversion and poor product selectivity have been observed using heterogeneous catalysts. In this study, for the first time, the efficient conversion of cellulose to lactic acid derivatives, which can be used as a green solvent and a potential precursor for fine chemicals and biodegradable polymers, over a Ga-doped Zn/H-nanozeolite Y (Ga-doped Zn/HNZY) catalyst is described. Under optimized conditions at 280°C in supercritical methanol, methyl lactate (ML) and methyl 2-methoxypropionate (MMP) are obtained in yields of 57.8% and 12.8%, respectively, from cellulose; these values are greater than those reported in previous studies conducted using heterogeneous catalysts. Using oakwood, ML and MMP are obtained in yields of 12.3% and 18.6%, respectively. A large external surface area of the HNZY support and the synergistic effect of Ga doping on ZnO enhance Lewis acid sites with the simultaneous decrease of the Br?nsted acid sites. This unique catalyst (Ga-doped Zn/HNZY) is beneficial for controlling the consecutive reaction pathways of the decomposition of cellulose to glucose, retro-aldol condensation to trioses, and intramolecular Cannizzaro reaction to ML.
- Verma, Deepak,Insyani, Rizki,Suh, Young-Woong,Kim, Seung Min,Kim, Seok Ki,Kim, Jaehoon
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supporting information
p. 1969 - 1982
(2017/06/09)
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- Chemocatalytic Conversion of Cellulosic Biomass to Methyl Glycolate, Ethylene Glycol, and Ethanol
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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
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p. 1390 - 1394
(2017/04/14)
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- Synthesis of a novel polyester building block from pentoses by tin-containing silicates
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We report here the direct formation of the new chemical product trans-2,5-dihydroxy-3-pentenoic acid methyl ester from pentoses using tin-containing silicates as catalysts. The product is formed under alkali-free conditions in methanol at temperatures in the range 140-180 °C. The highest yields are found using Sn-Beta as the catalyst. Under optimised conditions, a yield of 33% is achieved. Purified trans-2,5-dihydroxy-3-pentenoic acid methyl ester was used for co-polymerisation studies with ethyl 6-hydroxyhexanoate using Candida antarctica lipase B as the catalyst. The co-polymerisation yields a product containing functional groups originating from trans-2,5-dihydroxy-3-pentenoic acid methyl ester in the polyester backbone. The reactivity of the incorporated olefin and hydroxyl moieties was investigated using trifluoroacetic anhydride and thiol-ene chemistry, thus illustrating the potential for functionalising the new co-polymers.
- Elliot,Andersen,Tolborg,Meier,Sádaba,Daugaard,Taarning
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p. 985 - 996
(2017/01/13)
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- One-step method for synthesizing methyl lactate from biomass glycerol
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The invention relates to the technical field of preparation of methyl lactate, in particular to a one-step method for synthesizing the methyl lactate through catalytic conversion of the biomass glycerol in the presence of phosphotungstic acid by using a molecular sieve HZSM-5-supported bimetallic Au-Pd catalyst with a Si-Al ratio of 260. According to the method provided by the invention, the biomass glycerol is used as a raw material, HZSM-5-supported bimetallic gold-palladium alloy is used as a catalyst, and in a methanol solution in the presence of the phosphotungstic acid, a reaction is carried out in a high-pressure reaction kettle to prepare the methyl lactate. The yield of the methyl lactate can reach 96.0% and the conversion rate of the glycerol can reach 100%. The synergetic catalysis of the HZSM-5-supported bimetallic gold-palladium alloy catalyst and the phosphotungstic acid has the characteristics of low reaction temperature, low reaction pressure, high catalytic activity, high yield of the methyl lactate and the like; in addition, the technical process is safe, environment-friendly and the like, so that the method has a good industrial prospect.
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Paragraph 0018-0052
(2017/08/27)
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- Promotion effect of Sn on Au/Sn-USY catalysts for one-pot conversion of glycerol to methyl lactate
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Herein, hierarchical bifunctional catalysts of Sn-USY-supported Au nanoparticles were designed for the one-pot conversion of glycerol (GLY) to methyl lactate (MLA). Over Au/Sn-USY catalyst, 79% MLA yield can be obtained with a high selectivity (~90%). The promotion effect of Sn was investigated, and the interaction between extraframework SnOx and Au was confirmed by TEM, pyridine-FT-IR, CO-FT-IR, and XPS. The interaction promotes the dispersion of Au particles (smaller and much more uniform). This is important for the oxidation of GLY to 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GA), which are the intermediate species for the conversion of GLY to MLA. Meanwhile, introduction of Sn modified the acid properties of the catalyst, which are critical for the selective conversion of DHA and GA to MLA.
- Lu, Tianliang,Fu, Xiaomin,Zhou, Lipeng,Su, Yunlai,Yang, Xiaomei,Han, Li,Wang, Jianfeng,Song, Chengying
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p. 7274 - 7284
(2017/11/07)
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- Hierarchically porous Sn-β zeolites: Via an OSDA-free synthesis
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Hierarchically porous Sn-β zeolites were synthesized for the first time via a low-cost and environmentally benign strategy without using an organic structure directing agent, which still showed higher catalytic performance for triose sugar (DHA) into lactate than the traditional nano-sized Sn-β zeolites synthesized with expensive tetraethylammonium hydroxide.
- Yao, Ji-Kang,Fu, Kai-Rui,Wang, Yi-Chen,Li, Tian-Duo,Liu, Hai-Xia,Wang, Jin-Gui
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p. 3214 - 3218
(2017/07/28)
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- Mechanistic insights into the production of methyl lactate by catalytic conversion of carbohydrates on mesoporous Zr-SBA-15
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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
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p. 207 - 216
(2015/12/04)
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- Method for preparing methyl lactate through supported nickel oxide catalyzed monosaccharide conversion in near critical methanol medium
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The invention discloses a method for preparing methyl lactate through supported nickel oxide catalyzed monosaccharide conversion in a near critical methanol medium. The method comprises the following steps: 1, adding monosaccharide, methanol and a supported nickel oxide catalyst to a high-temperature and high-pressure reaction kettle with a stirring function, wherein the monosaccharide is five-membered sugar, six-membered sugar or a five-membered sugar and six-membered sugar mixture; 2, starting stirring, heating above added materials to 140-240DEG C, and reacting the materials for 1-12h; and 3, cooling a material obtained after the reaction ends to room temperature, filtering the cooled material, rectifying the obtained filtrate to obtain a methyl lactate product and methanol for reuse, washing filter residues containing the catalyst with methanol, and drying the catalyst for reuse. The method for preparing methyl lactate through monosaccharide conversion has the advantages of high raw material utilization rate, high methyl lactate yield, and great reduction of the separation cost, low price and good reusability of the catalyst supported nickel oxide, good mass transfer performance of the near critical methanol used as a solvent and a reactant, greenness and good industrial application prospect.
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Paragraph 0115; 0116
(2018/02/04)
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- PREPARATION OF 2,5,6-TRIHYDROXY-3-HEXENOIC ACID AND 2,5-DIHYDROXY-3-PENTENOIC ACID AND ESTERS THEREOF FROM C6 AND C5 SUGARS
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Preparation of 2,5,6-trihydroxy-3-hexenoic acid and 2,5- dihydroxy-3-pentenoic acid and esters thereof from C6 and C5 sugarsin the presence of a Lewis Acid material, wherein the yield of the 2,5,6-trihydroxy-3-hexenoic acid or2,5- dihydroxy-3-pentenoic acidor esters thereof exceeds15 %.
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Page/Page column 14; 19
(2017/01/02)
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- Chemocatalysis of sugars to produce lactic acid derivatives on zeolitic imidazolate frameworks
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Several research studies related to biorefining have focused on developing routes for biomass conversion into biomaterials or platform molecules. In this work, the zeolitic imidazolate frameworks (ZIFs) ZIF-8 and ZIF-67 have been tested as catalysts in th
- Murillo, Beatriz,Zornoza, Beatriz,De La Iglesia, Oscar,Téllez, Carlos,Coronas, Joaquín
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- Actinic ray-sensitive or radiation-sensitive resin composition, and, actinic ray-sensitive or radiation-sensitive film and pattern forming method, each using the same
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An actinic ray-sensitive or radiation-sensitive resin composition in the present invention contains a nitrogen-containing compound (N) which is represented by the following general formula (N1): wherein, in the general formula (N1), X represents a group including a hetero atom; L represents a single bond or an alkylene group; R2 represents a substituent, in the case where a plurality of R2's are present, they may be the same as or different from each other and a plurality of R2's may be bonded to each other to form a ring; R3 represents a hydrogen atom or a substituent; and n represents an integer of 0 to 4.
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- Ru-MACHO-Catalyzed Highly Chemoselective Hydrogenation of α-Keto Esters to 1,2-Diols or α-Hydroxy Esters
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A ruthenium pincer catalyst has been shown to be highly effective for the hydrogenation of a wide range of α-keto esters, affording either diols or hydroxy esters depending on the choice of reaction conditions. Strong base, high temperature, and pressure favor the formation of diols whilst the opposite is true for the hydroxy esters.
- Gao, Shaochan,Tang, Weijun,Zhang, Minghui,Wang, Chao,Xiao, Jianliang
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supporting information
p. 1748 - 1752
(2016/07/06)
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- Synthesis and catalytic performance of ruthenium complexes ligated with rigid: O -(diphenylphosphino)aniline for chemoselective hydrogenation of dimethyl oxalate
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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
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p. 45512 - 45518
(2016/06/06)
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- Preparation method of 2-hydroxy acid ester
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The invention relates to a preparation method of 2-hydroxy acid ester and belongs to the technical field of organic synthesis. According to the preparation method of 2-hydroxy acid ester, 2-hydroxy alkyl cyanogens is taken as a raw material to be added to a reaction solution formed by hydrogen chloride, alcohol and water, and after reaction, 2-hydroxy acid ester is obtained. According to the preparation method of 2-hydroxy acid ester, use of a large amount of nonpolar solvent is not needed, and a target product can be obtained by a one-pot method, thus lowering production cost, improving production efficiency and the purify of the target product, and having energy-saving and environment-friendly effects.
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Paragraph 0034; 0036
(2017/04/11)
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- Method for preparing from glycolic acid ester from carbohydrate
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The invention provides a method for preparing glycolic acid ester from carbohydrate including cellulose, starch, hemicelluloses, cane sugar, glucose, fructose, fructosan, xylose and soluble xylooligosaccharide and a natural wood fibre raw material containing the above carbohydrate component. According to the method, carbohydrate or the natural wood fibre raw material containing the carbohydrate component used as a reaction material undergoes one-step catalytic conversion in an alcohol solvent of 100-400 DEG C by using one or more than two of tungsten oxide, tungsten sulfide, tungsten chloride, tungsten carbide, tungsten hydroxide, tungsten bronze, tungstic acid, tungstate, metatungstic acid, metatungstate, para-tungstic acid, paratungstate, peroxotungstic acid, peroxotungstate, tungsten-containing heteropoly acid and heteropolytungstate as a catalyst, so as to realize carbohydrate high-selectivity and high-yield preparation of glycolic acid ester. The reaction provided by the invention has remarkably advantages as follows: the raw materials are renewable resources, and atom economy is high.
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Paragraph 0023; 0046-0049
(2017/03/25)
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- Carbonylation of ethylenically unsaturated compounds
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A process for the carbonylation of ethylenically unsaturated compounds including vinyl esters and a process for the production of 3-hydroxy propanoate esters or acids. The process comprises reacting said compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system. The catalyst system is obtainable by combining: (a) a metal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentate ligand of general formula (I): X1(X2)-Q2-A-R—B-Q1-X3(X4).
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Page/Page column 48
(2016/06/01)
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- Synthesis of Sn-Beta with Exclusive and High Framework Sn Content
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Sn-Beta zeolite was prepared by acid dealumination of Beta zeolite, followed by dehydration and impregnation with anhydrous SnCl4. The formation of extraframework Sn (EFSn) species was prevented by the removal of unreacted SnCl4 in a methanol washing step prior to calcination. The resulting Sn-Beta zeolites were characterized by X-ray diffraction, Ar physisorption, NMR, UV/Vis, and FTIR spectroscopy. These well-defined Lewis acid zeolites exhibit good catalytic activity and selectivity in the conversion of 1,3-dihydroxyacetone to methyl lactate. Their performance is similar to a reference Sn-Beta zeolite prepared by hydrothermal synthesis. Sn-BEA zeolites that contain EFSn species exhibit lower catalytic activity; the EFSn species also catalyze formation of byproducts. DFT calculations show that partially hydrolyzed framework Sn-OH species (open sites), rather than the tetrahedral framework Sn sites (closed sites), are the most likely candidate active sites for methyl lactate formation.
- Van Der Graaff, William N. P.,Li, Guanna,Mezari, Brahim,Pidko, Evgeny A.,Hensen, Emiel J. M.
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p. 1152 - 1160
(2015/04/14)
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- Tandem catalytic conversion of glycerol using solid catalysts followed by transesterification to produce alkyl lactate
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This study investigated alkyl lactate production from glycerol by tandem processes which included glycerol conversion to calcium lactate using solid catalysts and subsequent transesterification of calcium lactate to alkyl lactate using methanol/ethanol and carbon dioxide. The effect of reaction conditions on alkyl lactate production was systematically investigated. A central composite design (CCD) and response surface methodology were used to design the experiments and evaluate the optimum process conditions. At the optimum conditions, the methyl lactate yield reached 57 mol% with a glycerol conversion of 94 mol% using refined glycerol. A yield of approximately 42 mol% for ethyl lactate was obtained using refined glycerol at the optimum conditions. Similar glycerol conversion and alkyl lactate yields were obtained using crude glycerol, indicating that the impurities in the crude glycerol had no significant effects on alkyl lactate production. The examination of regenerated catalysts that had been reused twice showed no negative effects on glycerol conversion and methyl lactate production. Compared to the traditional lactic acid and alkyl lactate production, this two-step process for alkyl lactate production from glycerol is both economical and environmentally benign since no gypsum was produced and the solid catalysts can be regenerated and reused.
- Ren, Shoujie,Ye, X. Philip,Ayers, Paul D.
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p. 53230 - 53239
(2015/06/30)
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- METHODS OF MAKING ALKYL LACTATES AND ALKYL LEVULINATES FROM SACCHARIDES
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Unique methods have been developed to convert saccharides into value-added products such as alkyl lactates, lactic acid, alkyl levulinates, levulinic acid, and optionally alkyl formate esters and/or hydroxymethylfurfural (HMF). Useful catalysts include Lewis acid catalysts and Br?nsted acid catalysts including mineral acids, metal halides, immobilized heterogeneous catalysts functionalized with a Br?nsted acid group or a Lewis acid group, or combinations thereof. The saccharides are contacted with the catalyst in the presence of various alcohols.
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Page/Page column 4
(2015/02/25)
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- Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures
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Retro-aldol reactions have been implicated as the limiting steps in catalytic routes to convert biomass-derived hexoses and pentoses into valuable C2, C3, and C4 products such as glycolic acid, lactic acid, 2-hydroxy-3-butenoic acid, 2,4-dihydroxybutanoic acid, and alkyl esters thereof. Due to a lack of efficient retro-aldol catalysts, most previous investigations of catalytic pathways involving these reactions were conducted at high temperatures (≥160 °C). Here, we report moderate-temperature (around 100 °C) retro-aldol reactions of various hexoses in aqueous and alcoholic media with catalysts traditionally known for their capacity to catalyze 1,2-intramolecular carbon shift (1,2-CS) reactions of aldoses, i.e., various molybdenum oxide and molybdate species, nickel(II) diamine complexes, alkali-exchanged stannosilicate molecular sieves, and amorphous TiO2-SiO2 coprecipitates. Solid Lewis acid cocatalysts that are known to catalyze 1,2-intramolecular hydride shift (1,2-HS) reactions that enable the formation of α-hydroxy carboxylic acids from tetroses, trioses, and glycolaldehyde, but cannot readily catalyze retro-aldol reactions of hexoses and pentoses at these moderate temperatures, are shown to be compatible with the aforementioned retro-aldol catalysts. The combination of a distinct retroaldol catalyst with a 1,2-HS catalyst enables lactic acid and alkyl lactate formation from ketohexoses at moderate temperatures (around 100 °C), with yields comparable to best-reported chemocatalytic examples at high temperature conditions (≥160 °C). The use of moderate temperatures enables numerous desirable features such as lower pressure and significantly less catalyst deactivation.
- Orazov, Marat,Davis, Mark E.
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p. 11777 - 11782
(2015/10/12)
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- Rapid synthesis of beta zeolites
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The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.
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- Platinum functionalized multiwall carbon nanotube composites as recyclable catalyst for highly efficient asymmetric hydrogenation of methyl pyruvate
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Platinum functionalized carbon materials such as carbon fibres, graphene, MWNTs (multiwalled carbon nanotubes) and activated carbon were used as heterogeneous catalytic systems for asymmetric hydrogenation of α-ketoester i.e. methyl pyruvate using cinchonidine (CD) as a chiral modifier. Interestingly, the MWNTs exhibited excellent enantioselectivity (>99% ee) and conversion (99%) in comparison to other Pt/C systems due to their high surface area. Furthermore, in the case of Pt/MWNTs, Pt nanoparticles are found to be uniformly dispersed and bound to the MWNTs acting like a single atom catalyst. Time-dependent nuclear magnetic resonance (NMR) studies, cyclic voltammetry (CV) and diffuse reflectance spectroscopy (DRS) have been carried out to study substrate-modifier-catalyst interactions. Recyclability of the catalyst was also tested up to ten cycles without losing any significant catalytic activity.
- Sharma, Poonam,Sharma, Rakesh K.
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p. 102481 - 102487
(2015/12/11)
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- New Route to Stabilize Ruthenium Nanoparticles with Non-Isolable Chiral N-Heterocyclic Carbenes
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Ru nanoparticles (RuNPs) stabilized by non-isolable chiral N-heterocyclic carbenes (NHCs), namely SIDPhNp ((4S,5S)-1,3-di(naphthalen-1-yl)-4,5-diphenylimidazolidine) and SIPhOH ((S)-3-((1S,2R)-2-hydroxy-1,2-diphenylethyl)-1-((R)-2-hydroxy-1,2-diphenylethyl)-4,5-dihydro-3H-imidazoline), have been synthesized through a new procedure that does not require isolation of the free carbenes. The obtained RuNPs have been characterized by state-of-the-art techniques and their surface chemistry has been investigated by FTIR and solid-state MAS NMR upon the coordination of CO, which indicated the presence of free and reactive Ru sites. Their catalytic activity has been tested in various hydrogenation reactions involving competition between different sites, whereby interesting differences in selectivity were observed, but no enantioselectivity.
- Martnez-Prieto, Luis Miguel,Ferry, Anglique,Lara, Patricia,Richter, Christian,Philippot, Karine,Glorius, Frank,Chaudret, Bruno
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p. 17495 - 17502
(2016/01/25)
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