Xi:Irritant;97-64-3Relevant articles and documents
Ni-Catalyzed C(sp3)–O Arylation of α-Hydroxy Esters
Monteith, John J.,Rousseaux, Sophie A. L.
supporting information, p. 9485 - 9489 (2021/12/09)
A Negishi cross-coupling of α-hydroxy ester derivatives and arylzinc reagents has been developed. This reaction tolerates both primary and secondary C(sp3)–O alcohol precursors and achieves efficient cross-coupling under Ni catalysis without the need for added external metal reductant, photocatalyst, or additives. The arylation of readily accessible C(sp3)–O electrophiles in this operationally simple, rapid, and mild reaction provides a complementary way of accessing desirable α-aryl ester products.
One-pot conversion of dihydroxyacetone into ethyl lactate by Zr-based catalysts
Shi, Junjun,Li, Fukun,Zhang, Jie,Li, Ning,Wang, Xingmin,Zhang, Xianming,Liu, Yunqi
, p. 10935 - 10940 (2021/03/23)
Efficient strategies for producing bio-based reagents from sustainable biomass are highly attractive for cost-effective sustainable manufacturing. In this study, a series of eco-friendly Zr-based catalysts (basic zirconium carbonate, zirconium dioxide and zirconium hydroxide) were investigated for the efficient conversion of dihydroxyacetone to ethyl lactate in a one-pot system, in which basic zirconium carbonate exhibited the best performance with 100% dihydroxyacetone conversion and 85.3% EL (ethyl lactate) yield at 140 °C, 4.0 h and 1.0 MPa N2. The improved activity of basic zirconium carbonate could be attributed to the synergistic effect among acid and base active sites. Furthermore, this low-cost catalyst shows improved thermochemical stability and recyclability under optimal conditions, where no significant decrease in activity was observed after three runs. This catalytic process could be identified as a promising alternative to produce ethyl lactate from renewable biomass and its derivatives.
Enhancing Effect of Residual Capping Agents in Heterogeneous Enantioselective Hydrogenation of α-keto Esters over Polymer-Capped Pt/Al2O3
Chung, Iljun,Song, Byeongju,Kim, Jeongmyeong,Yun, Yongju
, p. 31 - 42 (2021/01/11)
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.
Asymmetric Synthesis of N-Substituted α-Amino Esters from α-Ketoesters via Imine Reductase-Catalyzed Reductive Amination
Yao, Peiyuan,Marshall, James R.,Xu, Zefei,Lim, Jesmine,Charnock, Simon J.,Zhu, Dunming,Turner, Nicholas J.
supporting information, p. 8717 - 8721 (2021/03/16)
N-Substituted α-amino esters are widely used as chiral intermediates in a range of pharmaceuticals. Here we report the enantioselective biocatalyic synthesis of N-substituted α-amino esters through the direct reductive coupling of α-ketoesters and amines employing sequence diverse metagenomic imine reductases (IREDs). Both enantiomers of N-substituted α-amino esters were obtained with high conversion and excellent enantioselectivity under mild reaction conditions. In addition >20 different preparative scale transformations were performed highlighting the scalability of this system.
Process method for producing ethyl lactate by using reactive distillation dividing wall tower technology
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Paragraph 0039; 0040; 0046-0049, (2020/02/14)
The invention provides a process method for producing ethyl lactate by using a reactive distillation dividing wall tower technology. According to the process, the production of ethyl lactate is completed in a reactive distillation dividing wall tower, an esterification reaction of lactic acid and ethanol is completed in a middle section feeding side reaction section of the reactive distillation dividing wall tower to generate ethyl lactate and water, and the separation of ethanol and esterification product water is completed through a middle section extraction side rectification section, meanwhile, ethyl lactate purification is realized in a middle section feeding side stripping section and a middle section extracting side stripping section, and finally a food-grade ethyl lactate product is obtained at the bottom of the tower. Compared with the prior art, the process has the advantages of high ethyl lactate product yield, high equipment integration, short process flow, low one-time investment, low operation cost and the like.
Bi-Functional Magnesium Silicate Catalyzed Glucose and Furfural Transformations to Renewable Chemicals
Kumar, Abhinav,Srivastava, Rajendra
, p. 4807 - 4816 (2020/08/24)
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.
Method for preparing lactate
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Paragraph 0084-0085, (2020/06/30)
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.
Method for preparing lactate by catalyzing pyruvic aldehyde
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Paragraph 0189; 0190; 0210, (2020/07/02)
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.
NMR Spectroscopic Characterization of Flame-Made Amorphous Silica-Alumina for Cyclohexanol and Glyceraldehyde Conversion
Wang, Zichun,Jiang, Yijiao,Stampfl, Catherine,Baiker, Alfons,Hunger, Michael,Huang, Jun
, p. 287 - 293 (2019/12/12)
Amorphous silica-aluminas (ASAs), possessing both Br?nsted acid sites (BAS) and Lewis acid sites (LAS), are important bifunctional catalysts in various industrial applications. Solid-state NMR spectroscopy has been widely used for characterizing the local structure and the surface sites of ASAs with probe molecules. In this work, four-, five- and six-coordinated Al species have been observed on the flame-made ASAs by 27Al MQ MAS NMR experiment. 1H/27Al TRAPDOR MAS NMR experiments confirmed that surface Al species contribute to the formation of BAS and protonate ammonia probe molecules. The adsorption of ammonia on Lewis acidic Al sites (δ1H=3.0 ppm) was evidenced by various 1H MAS NMR experiments on samples dehydrated at different temperatures, allowing the distinction from ammonium ions (δ1H=6.7 ppm) formed at BAS. The signal of ammonia adsorbed on LAS increased with increasing Al content in the ASAs. These properties together with the absence of pore diffusional constraints render the flame-made ASAs excellent catalysts for cyclohexanol dehydration and the conversion of glyceraldehyde in ethanol to ethyl lactate, outperforming the performance of other ASAs or zeolites.
A PROCESS FOR THE PREPARATION OF PLATFORM CHEMICALS FROM SUGAR USING ACID CATALYST
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Page/Page column 8, (2020/07/31)
The present invention relates to a process for the preparation of value added chemicals such as ethyl levulinate from a glucose or other sugars catalyzed by a mixture of a Lewis and a Bronsted acid catalyst.
