- Photothermal strategy for the highly efficient conversion of glucose into lactic acid at low temperatures over a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide catalyst
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The conversion of carbohydrates into lactic acid has attracted increasing attention owing to the broad applications of lactic acid. However, the current methods of thermochemical conversion commonly suffer from limited selectivity or the need for harsh conditions. Herein, a light-driven system of highly selective conversion of glucose into lactic acid at low temperatures was developed. By constructing a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide composite catalyst (CNT/LDHs), the highest lactic acid yield of 88.6% with 90.0% selectivity was achieved. The performance of CNT/LDHs for lactic acid production from glucose is attributed to the following factors: (i) CNTs generate a strong heating center under irradiation, providing heat for converting glucose into lactic acid; (ii) LDHs catalyze glucose isomerization, in which the photoinduced OVs (Lewis acid) in LDHs under irradiation further improve the catalytic activity; and (iii) in a heterogeneous-homogeneous synergistically catalytic system (LDHs-OH-), OH- ions are concentrated in LDHs, forming strong base sites to catalyze subsequent cascade reactions.
- Duo, Jia,Jin, Binbin,Jin, Fangming,Shi, Xiaoyu,Wang, Tianfu,Ye, Xin,Zhong, Heng
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p. 813 - 822
(2022/02/09)
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- Acceptorless dehydrogenation of primary alcohols to carboxylic acids by self-supported NHC-Ru single-site catalysts
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The acceptorless dehydrogenation of diverse aromatic and aliphatic primary alcohols to corresponding carboxylic acids has been accomplished by self-supported NHC-Ru single-site catalysts under mild reaction conditions. Besides broad substrates with excellent activity, selectivity and good tolerance to sensitive functional groups, the solid single-site catalyst could be recovered and reused for more than 20 runs without deactivation. Remarkably, up to 1.8 × 104 turnover numbers could be achieved by this newly developed sustainable protocol in gram scale at low catalyst loading, highlighting its potential in industry.
- Yin, Shenxiang,Zheng, Qingshu,Chen, Jie,Tu, Tao
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p. 165 - 172
(2022/03/23)
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- Catalytic wet air oxidation of D-glucose by perovskite type oxides (Fe, Co, Mn) for the synthesis of value-added chemicals
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The conversion of common biomasses derived, as D-glucose, into value-added chemicals has received highest attention in the last few years. Among all processes, the catalytic wet air oxidation (CWAO) of derived biomasses using noble metal-based heterogeneo
- Geobaldo, Francesco,Pirone, Raffaele,Russo, Nunzio,Scelfo, Simone
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- Ce promoted Cu/γ-Al2O3 catalysts for the enhanced selectivity of 1,2-propanediol from catalytic hydrogenolysis of glucose
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Ce promoted Cu/γ-Al2O3 catalysts were prepared with varying amounts of Cu (x = 0–10 wt%) and Ce (y = 0–15 wt%). The prepared catalysts were characterized and tested for the conversion of aqueous glucose (5 wt%) to 1,2-propanediol in a batch reactor. 10%Ce-8%Cu/γ-Al2O3 showed the complete conversion of glucose with 62.7% selectivity of 1,2-propanediol and total glycols (1,2-propanediol, ethylene glycol & 1,2-butanediol) of 81% at milder reaction conditions. Cu facilitated the hydrogenation activity and Ce loading optimize the acid/base sites of Cu/γ-Al2O3 which obtain high selectivity of 1, 2-propanediol. Catalyst reusability is reported.
- Balachandran Kirali, Arun Arunima,Marimuthu, Banu,Sreekantan, Sreejith
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- Visible-light-driven prompt and quantitative production of lactic acid from biomass sugars over a N-TiO2photothermal catalyst
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Chemocatalytic production of lactic acid from biomass feedstock is an alternative route with high potential, but with the prerequisites of long reaction time, high temperature, and/or a tailored catalyst. In this work, an N-TiO2 photothermal catalyst prepared by a simple sol-gel method using urea as a nitrogen and carbon source could catalyse a variety of biomass sugars to quantitatively produce lactic acid (up to 98.9% yield) in water under visible light and at a low temperature of 60 °C in a time as short as 30 min. N-TiO2 provides a suitable valence band position (2.51 eV) for the photo-oxidation reaction, with more active species being formed on the catalyst surface (e.g., h+, e-, OH and O2) and a light-induced heating effect caused by the carbon photothermal layer, which can effectively activate carbohydrates to undergo a cascade reaction process. Theoretical calculations show that the charge of N-TiO2 is highly separated, in which the N element acts as an electron trap and is enriched with plenty of electrons, leading to effective isolation of holes and electrons. In addition, the N-TiO2 catalyst exhibits good reusability and can be recycled with little loss of activity. The developed N and C-enhanced photothermal synergistic protocol opens up an avenue for producing organic acids from renewable biomass resources under mild conditions. This journal is
- Cao, Yingying,Chen, Dandan,Li, Hu,Meng, Ye,Saravanamurugan, Shunmugavel
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p. 10039 - 10049
(2021/12/27)
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- GNCC AND/OR PCC AS A CATALYTIC CARRIER FOR METAL SPECIES
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The present invention refers to a catalytic system comprising a transition metal compound on a solid carrier, wherein the content of the transition metal compound on the surface of the solid carrier is from 0.1 to 30 wt.-%, based on the dry weight of the solid carrier. Furthermore, the present invention refers to a method for manufacturing the catalytic system, the use of the inventive catalytic system in a chemical reaction, the use of a solid carrier loaded with a transition metal compound as a catalyst and to granules mouldings or extrudates comprising the catalytic system.
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Page/Page column 31-32
(2021/04/02)
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- Support effect in Co3O4-based catalysts for selective partial oxidation of glycerol to lactic acid
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Co3O4 supported on CeO2, ZrO2 and TiO2, were used as catalysts in glycerol partial oxidation to lactic acid. The aim was to establish the influence of the support on the cobalt-derived catalysts activity. The most active catalyst based on TOF followed the order: Co3O4/CeO2 (1.2 × 10?1 s?1) > Co3O4/ZrO2 (8.3 × 10-2 s?1) > Co3O4/TiO2 (3.0 × 10-2 s?1), with lactic acid selectivity at comparable glycerol conversion (53.5 ± 5.5 %) being higher when using CeO2 support, Co3O4/CeO2 (90 %) > Co3O4/ZrO2 (78 %) > Co3O4/TiO2 (68 %). These results indicated that the support type not only influenced activity but also selectivity to lactic acid. The Co3O4/CeO2 catalyst with less exposed cobalt species at the surface enriched in Co3+ ions, a more homogeneous composition of cobalt species being reduced at low temperatures, with acid sites of middle strength and lower density of acidic sites, is at the origin of a greater selectivity towards lactic acid, in addition this catalyst was active in 4 catalytic cycles.
- Torres, Sebastian,Palacio, Ruben,López, Diana
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- Effect of physicochemical parameters on the stability and activity of garlic alliinase and its use for in-situ allicin synthesis
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Garlic is a well-known example of natural self-defence system consisting of an inactive substrate (alliin) and enzyme (alliinase) which, when combined, produce highly antimicrobial allicin. Increase of alliinase stability and its activity are of paramount importance in various applications relying on its use for in-situ synthesis of allicin or its analogues, e.g., pulmonary drug delivery, treatment of superficial injuries, or urease inhibitors in fertilizers. Here, we discuss the effect of temperature, pH, buffers, salts, and additives, i.e. antioxidants, chelating agents, reducing agents and cosolvents, on the stability and the activity of alliinase extracted from garlic. The effects of the storage temperature and relative humidity on the stability of lyophilized alliinase was demonstrated. A combination of the short half-life, high reactivity and non-specificity to particular proteins are reasons most bacteria cannot deal with allicin's mode of action and develop effective defence mechanism, which could be the key to sustainable drug design addressing serious problems with escalating emergence of multidrug-resistant (MDR) bacterial strains.
- Janska, Petra,Knejzlík, Zdenek,Perumal, Ayyappasamy Sudalaiyadum,Jurok, Radek,Tokarova, Viola,Nicolau, Dan V.,Tepanek, FrantisekS,Kaspar, Ondrej
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- Parahydrogen-Induced Polarization Relayed via Proton Exchange
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The hyperpolarization of nuclear spins is a game-changing technology that enables hitherto inaccessible applications for magnetic resonance in chemistry and biomedicine. Despite significant advances and discoveries in the past, however, the quest to establish efficient and effective hyperpolarization methods continues. Here, we describe a new method that combines the advantages of direct parahydrogenation, high polarization (P), fast reaction, and low cost with the broad applicability of polarization transfer via proton exchange. We identified the system propargyl alcohol + pH2 → allyl alcohol to yield 1H polarization in excess of P ≈ 13% by using only 50% enriched pH2 at a pressure of ≈1 bar. The polarization was then successfully relayed via proton exchange from allyl alcohol to various target molecules. The polarizations of water and alcohols (as target molecules) approached P ≈ 1% even at high molar concentrations of 100 mM. Lactate, glucose, and pyruvic acid were also polarized, but to a lesser extent. Several potential improvements of the methodology are discussed. Thus, the parahydrogen-induced hyperpolarization relayed via proton exchange (PHIP-X) is a promising approach to polarize numerous molecules which participate in proton exchange and support new applications for magnetic resonance.
- Them, Kolja,Ellermann, Frowin,Pravdivtsev, Andrey N.,Salnikov, Oleg G.,Skovpin, Ivan V.,Koptyug, Igor V.,Herges, Rainer,H?vener, Jan-Bernd
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supporting information
p. 13694 - 13700
(2021/09/07)
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- METHODS FOR SYNTHESIZING ANHYDROUS LACTIC ACID
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A method of synthesizing anhydrous lactic acid is provided by reacting a compound of formula (Ia): with an acid compound of formula HnX in a first solvent to produce a reaction mixture comprising a compound of formula (Ib) and a lactic acid compound of formula (I) in solution with the first solvent and/or water. n is an integer other than 0, x is 0, or an integer other than 0, M is an alkali metal or alkaline earth metal and X is the conjugate base of the acid compound of formula HnX. The resulting reaction mixture is filtered to produce a filtrate containing lactic acid in solution. The filtrate is crystalized from a second solvent to produce anhydrous lactic acid.
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Paragraph 0038; 0055
(2021/11/13)
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- The selective oxidation of glycerol over metal-free photocatalysts: insights into the solvent effect on catalytic efficiency and product distribution
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Selective oxidation of glycerol to high value-added derivatives is a promising biomass conversion pathway, but the related reaction mechanism, in particular the solvent effect, is rarely studied. In this work, O-doped g-C3N4was used as a metal-free catalyst to catalyze the selective oxidation of glycerol in different solvents. It was found that solvents can affect both catalytic efficiency and product distribution. A series of controlled experiments and theoretical calculation were applied to attest that the difference in interaction between glycerol and catalysts in different solvents is the main factor: competitive adsorption and hydrogen bond network from water inhibit the adsorption and activation of glycerol on the catalyst surface and reduce the conversion efficiency, while in acetonitrile, the stronger adsorption makes the oxidation reaction continue to yield esters. Two reaction routes in different solvents over O-doped g-C3N4are proposed for the first time, which is helpful for people to better understand the related reaction mechanism.
- Fan, Mingming,Haryonob, Agus,Jiang, Pingping,Leng, Yan,Yue, Chengguang,Zhang, Pingbo
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p. 3385 - 3392
(2021/06/06)
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- Catalytic isomerization of dihydroxyacetone to lactic acid by heat treated zeolites
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Lactic acid can be prepared by isomerization of renewable dihydroxyacetone over acid catalysts. However, the activities of Lewis acid and Br?nsted acid sites in dihydroxyacetone isomerization are poorly understood. We prepared catalysts by heat treatment of ZSM-5. The heat treated ZSM-5 exhibited a greater Lewis acid site density and enhanced selectivity toward lactic acid. Dihydroxyacetone dehydration to the intermediate pyruvaldehyde was readily formed at 140 °C without added catalysts. Lewis acid sites were needed to convert pyruvaldehyde to lactic acid. Moreover, the Lewis acid site density was consistent with the order of catalytic performance, which suggested that the Lewis acid sites were the active sites for pyruvaldehyde rehydration. Conversely, the Br?nsted acid sites were key in formation of unwanted product from pyruvaldehyde. These findings highlight the potential use of commercial zeolites as adjustable solid Lewis acid catalysts in biomass conversion reactions in which Lewis acid sites are needed.
- Dong, Jie,Hossain, Md Anwar,Lalvani, Shashi B.,Mills, Kyle N.,Molley, Ashten M.,Rahaman, Mohammad Shahinur,Sathitsuksanoh, Noppadon,Sunkara, Mahendra K.,Tulaphol, Sarttrawut
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- Selectivity Switch in the Aerobic 1,2-Propandiol Oxidation Catalyzed by Diamine-Stabilized Palladium Nanoparticles
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Palladium nanoparticles stabilized by a sterically demanding secondary diamine ligand have been synthesized by hydrogen reduction of a palladium acetate complex bearing the corresponding diimine ligand. The obtained nanoparticles were used to catalyze the aerobic oxidation of 1,2-propandiol in n-hexane, and after their heterogenization onto a high surface area carbon, in water. In n-hexane (2,4-dimethyl-1,3-dioxolan-2-yl) methanol has been obtained as major product, whereas in water acetic acid with a selectivity of >85 % has been achieved. The selectivity switch observed was a clear induced by water. The robustness of diamine-stabilized palladium nanoparticles under real aerobic oxidation conditions has been proved by recycling experiments, TEM measurements of the recovered catalysts and by comparison of its performance with that of palladium nanoparticles generated by the metal vapor synthesis technique and supported onto the same carbon in the absence of the stabilizing diamine ligand.
- Oberhauser, Werner,Evangelisti, Claudio,Capozzoli, Laura,Manca, Gabriele,Casaletto, Maria Pia,Vizza, Francesco
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p. 2896 - 2906
(2021/05/06)
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- Designed sol-gel precursors for atomically dispersed Nb and Pb within TiO2as catalysts for dihydroxyacetone transformation
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The ‘bottom-up’ synthesis of homogeneously doped metal oxide nanoparticles (NPs) with precision at the atomic/molecular level offers many advantages. We report here the synthesis, structural characterization and hydrolytic behavior of newN-methyldiethanol
- Neto, Antonio de Brito Santiago,Alves da Cruz, Márcia Gabriely,Jeanneau, Erwann,Oliveira, Alcineia Concei??o,Essayem, Nadine,Mishra, Shashank
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supporting information
p. 1604 - 1609
(2021/02/16)
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- Electrochemical biomass upgrading: Degradation of glucose to lactic acid on a copper(ii) electrode
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Biomass upgrading-the conversion of biomass waste into value-added products-provides a possible solution to reduce global dependency on nonrenewable resources. This study investigates the possibility of green biomass upgrading for lactic acid production by electrochemically-driven degradation of glucose. Herein we report an electrooxidized copper(ii) electrode which exhibits a turnover frequency of 5.04 s-1 for glucose conversion. Chronoamperometry experiments under varied potentials, alkalinity, and electrode preparation achieved a maximum lactic acid yield of 23.3 ± 1.2% and selectivity of 31.1 ± 1.9% (1.46 V vs. RHE, 1.0 M NaOH) for a room temperature and open-to-atmosphere reaction. Comparison between reaction conditions revealed lactic acid yield depends on alkalinity and applied potential, while pre-oxidation of the copper had a negligible effect on yield. Post-reaction cyclic voltammetry studies indicated no loss in reactivity for copper(ii) electrodes after a 30 hour reaction. Finally, a mechanism dependent on solvated Cu2+ species is proposed as evidenced by similar product distributions in electrocatalytic and thermocatalytic systems.
- Greenlee, Lauren F.,Hestekin, Jamie,Ostervold, Lars,Perez Bakovic, Sergio I.
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p. 31208 - 31218
(2021/11/30)
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- Transfer hydrogenation of CO2into formaldehyde from aqueous glycerol heterogeneously catalyzed by Ru bound to LDH
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Aqueous glycerol was used in this study as a liquid-phase hydrogen source for the hydrogenation of CO2. It was found that hydrogen could be efficiently evolved from aqueous glycerol upon highly dispersed Ru on layered double hydroxide (LDH), inducing the transformation of CO2 into formaldehyde under base-free conditions at low temperature.
- Deng, Lidan,Liu, Xiaowei,Xu, Jie,Zhou, Zijian,Feng, Shixiang,Wang, Zheng,Xu, Minghou
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supporting information
p. 5167 - 5170
(2021/05/31)
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- Efficient photodegradation of 2-chloro-4-nitrophenol over Fe-doped BiOCl nanosheets with oxygen vacancy
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Photodegradation of organic pollutants emerged as a promising route for environmental remediation. Due to abundant localized electrons, oxygen vacancies (OVs) over BiOCl could promote the adsorption of organic pollutants and activation of oxygen to produce more reactive oxygen species (ROS) during the photocatalytic reaction. Considering the high oxidation potential (E0 = 1.8-2.7 V vs. NHE) of the hydroxyl radicals (OH), we introduced Fe dopant in the OV-associated BiOCl system (Fe-BOC) to build Fenton-like catalysts, which converted the H2O2 generated in the photoreaction to produce more OH for the photodegradation of 2-chloro-4-nitrophenol. Experimental results revealed that the concentration of H2O2 in the undoped BiOCl (BOC) photoreaction system was higher, while much more OH was detected in Fe-BOC, indicating that the Fenton-like reaction occurred for the conversion of H2O2 into OH over Fe-BOC. In addition, the better charge separation of Fe-BOC could motivate more surface e- for O2 activation into O2-. Thus, the more reactive oxygen species (OH and O2-) produced over Fe-BOC resulted in 3.1 times higher photocatalytic activity in contrast to that of BOC.
- Liu, Xiangming,Wu, Haoyuan,Xu, Hua,Yang, Xinmin,Ye, Jinhua
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p. 5119 - 5124
(2021/08/16)
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- Selective conversion of xylose to lactic acid over metal-based Lewis acid supported on γ-Al2O3 catalysts
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Gamma-alumina (γ-Al2O3) is a low-cost amphoteric solid catalyst which can enhance the transformation of D-xylose into lactic acid. The deposition of metal oxides on γ-Al2O3 could further improve the yield of lactic acid from xylose. Therefore, in this work, the thermochemical catalytic conversion of D-xylose to lactic acid using the Cr, Cu, Co, Ni, and Sn oxides supported on γ-Al2O3 as heterogeneous catalysts was studied. The effects of metal oxides on the D-xylose conversion to lactic acid activity of the catalysts were investigated. It was found that, under identical testing conditions (170 °C, 4 h), Cr/Al2O3 is superior to the other catalysts with the 99 % conversion of D-xylose and the lactic acid yield of 74%. The outstanding activity could be attributed to its richness in Lewis-acid sites. Since the highly active Cr/Al2O3 catalyst is composed of the earth-abundant materials and can be prepared by a simple process, it has feasibility for industrial-scale application.
- Kosri, Chanokporn,Kiatphuengporn, Sirapassorn,Butburee, Teera,Youngjun, Saran,Thongratkaew, Sutarat,Faungnawakij, Kajornsak,Yimsukanan, Chakrit,Chanlek, Narong,Kidkhunthod, Pinit,Wittayakun, Jatuporn,Khemthong, Pongtanawat
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p. 205 - 212
(2020/06/18)
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- Enhanced nonradical catalytic oxidation by encapsulating cobalt into nitrogen doped graphene: highlight on interfacial interactions
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Supported metal catalysts are widely used for heterogeneous catalytic processes (e.g., Fenton-like reaction), but the mechanisms of interfacial processes are still ambiguous. Herein, unique nanocarbon based catalysts with Co nanoparticles encapsulated in
- Yu, Xiaoyong,Wang, Lijing,Wang, Xin,Liu, Hongzhi,Wang, Ziyuan,Huang, Yixuan,Shan, Guoqiang,Wang, Weichao,Zhu, Lingyan
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supporting information
p. 7198 - 7207
(2021/03/29)
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- Efficient conversion of cellulose to lactic acid over yttrium modified siliceous Beta zeolites
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The selective one-pot synthesis of lactic acid (LA) from cellulose, and further the raw biomass, on heterogeneous catalysts is the key point for the development of biorefinery technology. Herein, we reported an yttrium (Y) modified siliceous Beta zeolites catalyst via two-step post-synthesis for highly efficient conversion of cellulose to LA. Under condition of 220 °C and 2 MPa N2, the cellulose could be transformed to LA with a yield of 49.2 % within 30 min, and the substrate can be extended to various raw biomass. It was demonstrated that the dealumination and modification of Y can efficiently modulate the acidity on the surface of zeolite. The dehydration products HMF and other derivatives were suppressed, and the yield of LA was correlated in line with the acid amount, which were attributed to the increased Lewis acidity originated by Y incorporation. These results contribute to the development of the green and efficient synthesis of bio-chemicals.
- Ye, Juan,Chen, Chenyu,Zheng, Ying,Zhou, Dan,Liu, Yunzhen,Chen, Denglong,Ni, Liufang,Xu, Gang,Wang, Fanan
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- Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
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Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
- Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
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p. 1949 - 1960
(2021/03/26)
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- HETEROGENEOUS CATALYST COMPLEX FOR CARBON DIOXIDE CONVERSION
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Proposed is a catalyst complex having high activity for carbon dioxide conversion reaction that converts carbon dioxide to useful compounds through reaction of carbon dioxide and hydrocarbon containing at least one hydroxyl group, and a carbon dioxide conversion process using the same, wherein the catalyst complex includes, as an active metal in the catalyst complex, at least one of noble metals and at least one of transition metals other than noble metals, thereby having high activity for the carbon dioxide conversion reaction.
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-
Paragraph 0150-0157
(2021/05/21)
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- Tin, molybdenum and tin-molybdenum oxides: Influence of Lewis and Bronsted acid sites on xylose conversion
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In this study, tin oxide (SnO2), molybdenum oxide (MoO3) and a mixed oxide based on tin and molybdenum (respectively, Sn100, Mo100 and SnMo25, synthesized by the impregnation method) were applied in xylose conversion. The best results were obtained employing Mo100 and SnMo25. In the presence of SnMo25, after 0.5 h, xylose conversions of 39.5%, 34.1% and 63.4% were obtained, respectively, at 110, 130 and 150 °C. For Mo100, conversions of 49.6%, 71.8% and 85.3% were attained under the same reaction conditions, showing that Mo100 provided the best conversion results. However, with the use of this catalyst there was an increase in the amount of soluble and insoluble polymeric material. In terms of the soluble products formed from xylose, depending on the reaction condition were detected xylulose (X), lyxose (L) and furfural (FUR), glyceraldehyde (GL), pyruvaldehyde (PYR), glycoaldehyde (GLYC), dihydroxyacetone (DHA), lactic acid (AL), levulinic acid (LA) and acetic acid (AA). However, with the use of Sn100 or without a catalyst (systems with low conversions) there was mainly the formation of lyxose. The use of Mo100 and SnMo25 (systems which exhibit high acidity) leads mainly to isomerization, epimerization and dehydration reactions, as in the case of the retro-aldol pathway and furfural conversion, highlighting the importance of Lewis and Bronsted acid sites in relation to modulating the selectivity of the systems.
- Meneghetti, Mario R.,Meneghetti, Simoni M. P.,Pryston, Dhara B. A.,da Silva Avelino, Débora Olimpio,dos Santos, Thatiane V.
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- Photocatalytic hydrogenation of nitrobenzene to aniline over titanium(iv) oxide using various saccharides instead of hydrogen gas
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Bare TiO2 photocatalyst almost quantitatively converted nitrobenzene to aniline with various saccharides without the use of hydrogen gas. Although aniline was formed when any saccharide was used, the use of disaccharides (lactose, maltose, and sucrose) de
- Aono, Yushiro,Ikeuchi, Kazuma,Imamura, Kazuya,Onda, Ayumu,Oto, Takahiro,Sakamoto, Yuki
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p. 32300 - 32304
(2021/12/02)
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- Method for preparing lactic acid
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The invention relates to a method for preparing lactic acid. The method comprises the following steps: contacting pyruvic aldehyde and water with a catalyst in a reactor, and reacting to obtain a product containing lactic acid, wherein the molar ratio of the pyruvic aldehyde to the water is 1:(40-350), the reaction temperature is 30-180 DEG C, the reaction time is 1-10 hours, the catalyst containsa 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-silicon molecular 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 lactic acid yield.
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-
Paragraph 0067-0098
(2020/06/30)
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- Synthesis of fluoride-containing high dimensionally structured nb oxide and its catalytic performance for acid reactions
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High dimensionally structured niobium oxide (HDS-NbO) containing fluoride (F-) was prepared by a hydrothermal synthesis. F- could be introduced into HDS-NbO by replacing lattice oxygen up to a solid F-/Nb ratio of 0.55. The introduction of an appropriate
- Hiyoshi, Norihito,Ishikawa, Satoshi,Kimura, Momoka,Motoki, Yuta,Shinoda, Mai,Tsurumi, Shota,Ueda, Wataru,Yoshida, Akihiro
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supporting information
(2020/07/13)
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- Method for preparing lactic acid by catalyzing pyruvic aldehyde
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The invention relates to a method for preparing lactic acid by catalyzing pyruvic aldehyde. The method comprises the following steps: contacting pyruvic aldehyde, water and a catalyst in a reactor, and reacting to obtain a product containing lactic acid, wherein the molar ratio of the pyruvic aldehyde to the water is 1:(40-350), the reaction temperature is 30-180 DEG C, the reaction time is 1-10 hours, the catalyst contains a tin-titanium-silicon molecular sieve, and the weight ratio of the pyruvic aldehyde to the tin-titanium-silicon molecular sieve based on dry basis weight is 1:(1-6). The method provided by the invention has high pyruvic aldehyde conversion rate and high lactic acid yield.
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-
Paragraph 0161-0202; 0208
(2020/07/02)
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- Selective and high yield transformation of glycerol to lactic acid using NNN pincer ruthenium catalysts
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The conversion of glycerol selectively to lactic acid has been accomplished in high yields (ca. 90%) by using a NNN pincer-Ru catalyst. DFT explains the role of the Ru-P bond and sterics in favoring the catalysis.
- Dutta, Moumita,Das, Kanu,Prathapa, Siriyara Jagannatha,Srivastava, Hemant Kumar,Kumar, Akshai
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supporting information
p. 9886 - 9889
(2020/09/09)
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- Cu catalysts supported on CaO/MgO for glycerol conversion to lactic acid in alkaline medium employing a continuous flow reaction system
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The production of lactic acid (LA) from glycerol in alkaline medium was investigated using Cu catalysts supported on CaO, MgO and xCaO/MgO (x = 5, 10, 15 wt%), employing a continuous flow reaction system over a period of 30 h. In addition to assessing the effect of the composition of the catalytic support, the influence of the temperature (200-260 °C), NaOH/glycerol molar ratio (0.5-1.5), hydroxide type (NaOH and KOH), as well as the influence of concentration (10 and 20 vol%) and purity of glycerol was investigated. The catalysts were prepared by a wet impregnation method and characterized by XRF, XRD, N2 adsorption-desorption, H2-TPR and CO2-TPD. The catalytic tests showed that the use of NaOH results in higher yields to LA. Cu catalysts supported on xCaO/MgO exhibited better catalytic performance than the CuCa and CuMg catalysts. The LA yield increases with the increase of the reaction temperature from 200 to 240 °C, and then decreases with a subsequent increase to 260 °C. NaOH/glycerol molar ratios greater than 1.25 are not necessary, since high yield to LA (96.9%) was obtained in the catalytic test performed using a molar ratio of 1.25. The catalysts showed excellent stability without evidence of deactivation over the evaluated period. This journal is
- Bruno, Arthur M.,Manfro, Robinson L.,Sim?es, Thiago D. R.,Souza, Mariana M. V. M.
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p. 31123 - 31138
(2020/11/17)
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- Spinel copper-iron-oxide magnetic nanoparticles with cooperative Cu(i) and Cu(ii) sites for enhancing the catalytic transformation of 1,2-propanediol to lactic acid under anaerobic conditions
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The aerobic catalytic oxidation of 1,2-propanediol (PDO) over non-noble metal (e.g. Cu) based catalysts usually suffers serious C3 product dissociation at high temperature, thus showing low lactic acid (LA) selectivity. Here, an alternative anaerobic catalysis strategy over spinel copper-iron-oxide magnetic nanoparticles (CuFeOx MNs) with the coexistence of Cu(i) and Cu(ii) dual sites is developed for the catalytic transformation of PDO to LA with a quantitative yield of co-product H2 in basic aqueous solution. The absence of O2 is beneficial for enhancing LA production in comparison with the presence of O2. The synergy between Cu(i) and Cu(ii) sites in CuFeOx MNs is vital for improving the catalytic performance as compared to Cu2O or CuO catalysts with Cu(i) or Cu(ii) sites alone. Cu1Fe1Ox MNs with a Cu/Fe mole ratio of 1/1 exhibit 94.5% LA selectivity and 72.6% PDO conversion at 160 °C for 8 h. Experimental results and DFT calculations suggest that the spinel CuFeOx MN based catalytic PDO transformation follows a favorable pathway of PDO → hydroxyacetone → lactaldehyde → lactic acid for LA production. In addition to the catalytic PDO transformation, the use of CuFeOx MNs can be extended to favor high activity and selectivity in the catalytic transformation of glycerol to LA (98.5% selectivity) and ethylene glycol to glyceric acid (97.8% selectivity). This work highlights the design of an alternative non-noble metal-based CuFeOx MN catalyst for efficiently catalyzing the transformation of bio-based polyols into value-Added carboxylic acids.
- Feng, Yonghai,Liu, Lei,Lu, Congming,Meng, Minjia,Rao, Dewei,Wang, Huijie,Yin, Hengbo,Zhang, Yunlei
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p. 8094 - 8107
(2020/12/31)
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- Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
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The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
- Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
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supporting information
(2020/07/15)
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- Highly efficient production of lactic acid from xylose using Sn-beta catalysts
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The efficient conversion of xylose into lactic acid, especially with the novel contribution of C2 components, was revealed over the heterogeneous Sn-beta catalyst in water with a very high lactic acid yield of 70.0 wt% at 200 °C for 60 min. The 13C NMR results indicated that glycolaldehyde (C2), the cleavage species of xylose condensate to erythrose (C4), subsequently, erythrose converts to lactic acid (C3) and to formic acid (C1) with the removal of a carbon atom. In this catalytic process, Sn acts as the Lewis acid site in the Si-O-Sn framework, and participates in the coupling and cracking of C-C bonds (C2 → C4 → C3) through the adsorption of α-protons to generate carbonium anions. Thus, more than 10 wt% lactic acid was obtained based on above pathway through the synergy of aldol addition, isomerization and retro-aldol condensation over the Sn-beta catalyst. This journal is
- Kong, Lingzhao,Li, Shenggang,Luo, Hu,Miao, Gai,Sun, Yuhan,Zhang, Yanfei,Zhao, Xinpeng,Zhu, Lijun
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supporting information
p. 7333 - 7336
(2020/11/25)
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- Synthesis of Dicarboxylic Acids from Aqueous Solutions of Diols with Hydrogen Evolution Catalyzed by an Iridium Complex
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A catalytic system for the synthesis of dicarboxylic acids from aqueous solutions of diols accompanied by the evolution of hydrogen was developed. An iridium complex bearing a functional bipyridonate ligand with N,N-dimethylamino substituents exhibited a high catalytic performance for this type of dehydrogenative reaction. For example, adipic acid was synthesized from an aqueous solution of 1,6-hexanediol in 97 % yield accompanied by the evolution of four equivalents of hydrogen by the present catalytic system. It should be noted that the simultaneous production of industrially important dicarboxylic acids and hydrogen, which is useful as an energy carrier, was achieved. In addition, the selective dehydrogenative oxidation of vicinal diols to give α-hydroxycarboxylic acids was also accomplished.
- Fujita, Ken-ichi,Toyooka, Genki
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- Roles of acidic sites in alumina catalysts for efficient d-xylose conversion to lactic acid
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This work investigated the conversion of d-xylose to lactic acid over heterogeneous Al2O3 and ZSM-5 catalysts in aqueous solution. γ-Al2O3, an abundant low cost catalyst, exhibited superior lactic acid yield (63 mol%) at 170 °C, compared to α-Al2O3, ZSM-5 catalysts and the reported data in the literature so far. Our experiment suggested that the outstanding lactic acid yield could be attributed to the large specific surface area and the abundance of Lewis acid sites in γ-Al2O3. In contrast, furfural selectivity was significantly promoted in the catalyst free system and the ZSM-5 catalyst, which has abundant Br?nsted acid sites, but lacks Lewis acid sites. The theoretical part revealed that reactive Lewis acid sites in γ-Al2O3 and the solvent play important roles in the C-C bond activation and thermodynamic stability of the d-xylose to lactic acid pathway. The green catalytic system proposed in this work shows great potential as an alternative method for lactic acid production for future industrial application. This journal is
- Kiatphuengporn, Sirapassorn,Junkaew, Anchalee,Luadthong, Chuleeporn,Thongratkaew, Sutarat,Yimsukanan, Chakrit,Songtawee, Siripit,Butburee, Teera,Khemthong, Pongtanawat,Namuangruk, Supawadee,Kunaseth, Manaschai,Faungnawakij, Kajornsak
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supporting information
p. 8572 - 8583
(2020/12/31)
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- Totally atom-economical synthesis of lactic acid from formaldehyde: combined bio-carboligation and chemo-rearrangement without the isolation of intermediates
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Non-fermentative chemoenzymatic transformations have attracted great interest from both academia and industry. Here, we report a green chemoenzymatic cascade reaction that converts the C1 compound formaldehyde into lactic acid using a newly identified formolase variant and NaOH as catalysts with 100% atom economy and 82.9% overall yield under near-ambient conditions. The engineered formolase variant in this study exhibits a 19-fold substantially improved activity and improved formaldehyde resistance (up to 500 mM) and alters the main product from two-carbon glycolaldehyde (GA) to three-carbon dihydroxyacetone (DHA). The crystal structures of the parent formolase and identified variants were resolved to elucidate the molecular reason for the obtained improvement. Molecular dynamics simulation and molecular mechanics/generalized born surface area (MM/GBSA) analysis suggested that the identified amino acid substitutions allow more stable TPP-GA complexes in the active center of the dimeric formolase which is beneficial for the subsequent DHA generation. This journal is
- Jiang, Huifeng,Li, Jinlong,Li, Tianzhen,Lin, Jianping,Liu, Haifeng,Liu, Pi,Liu, Weidong,Ma, Yanhe,Tan, Zijian,Tang, Zijing,Wei, Hongli,Zheng, Yingying,Zhu, Leilei
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supporting information
p. 6809 - 6814
(2020/11/10)
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- Lewis Acid and Base Catalysis of YNbO4 Toward Aqueous-Phase Conversion of Hexose and Triose Sugars to Lactic Acid in Water
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Amphoteric YNbO4 was synthesized by the simple coprecipitation using (NH4)3[Nb(O2)4] and Y(NO3)3, and examined as a new solid acid-base bifunctional catalyst for various reactions including aqueous-phase conversion of glucose to lactic acid. After drying the white precipitate at 353 K for 3 h, the resultant oxide is an amorphous YNbO4 with high densities of Lewis acid sites (0.18 mmol g?1) and base sites (0.38 mmol g?1). Negatively-charged lattice oxygen of amorphous YNbO4 functioned as Lewis base sites that promote a Claisen-Schmidt-type condensation reaction with acetylacetone and benzaldehyde with comparable activity to reference catalysts. Amorphous YNbO4 can also be applicable to the production of lactic acid from glucose in water, which gives relatively high yields (19.6 %) compared with other reference catalysts. Mechanistic studies using glucose-1-d and 2H nuclear magnetic resonance spectroscopy (NMR) revealed that YNbO4 first converts glucose to two carbohydrates (glyceraldehyde and pyruvaldehyde) through dehydration via the formation of 3-deoxyglucosone and subsequent retro-aldolization, and these intermediates are then converted to lactic acid by both dehydration and isomerization through hydride transfer.
- Kim, Minjune,Ronchetti, Silvia,Onida, Barbara,Ichikuni, Nobuyuki,Fukuoka, Atsushi,Kato, Hideki,Nakajima, Kiyotaka
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p. 350 - 359
(2019/11/14)
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- Method for preparing lactic acid by catalyzing dihydroxyacetone and/or glyceraldehyde
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The invention relates to a method for preparing lactic acid by catalyzing dihydroxyacetone and/or glyceraldehydes. The method comprises the following steps: contacting reaction raw materials, water and a catalyst in a reactor, and reacting to obtain a lactic acid-containing product, wherein the reaction raw materials contain dihydroxy acetone and/or glyceraldehyde, the molar ratio of dihydroxyacetone and/or glyceraldehyde to water is 1:(50-450), the reaction temperature is 30-180 DEG C, the reaction time is 1-10 hours, the catalyst contains a tin-titanium-silicon molecular sieve, and the weight ratio of dihydroxyacetone and/or glyceraldehyde to the tin-titanium-silicon molecular sieve (calculated as dry basis weight) is 1:(1-6). The method provided by the invention has high conversion rateof dihydroxyacetone/glyceraldehyde and high yield of lactic acid.
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Paragraph 0166-0177; 0180-0191; 0194-0209
(2020/06/30)
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- Selective Catalytic Dehydrogenative Oxidation of Bio-Polyols to Lactic Acid
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The global demand for lactic acid (LA) is increasing due to its successful application as monomer for the manufacture of bioplastics. Although N-heterocyclic carbene (NHC) iridium complexes are promising molecular catalysts for LA synthesis, their instabilities have hindered their utilization especially in commercial applications. Here, we report that a porous self-supported NHC-iridium coordination polymer can efficiently prevent the clusterization of corresponding NHC-Ir molecules and can function as a solid molecular recyclable catalyst for dehydrogenation of bio-polyols to form LA with excellent activity (97 percent) and selectivity (>99 percent). A turnover number of up to 5700 could be achieved in a single batch, due to the synergistic participation of the Ba2+ and hydroxide ions, as well as the blockage of unwanted pathways by adding methanol. Our findings demonstrate a potential route for the industrial production of LA from cheap and abundant bio-polyols, including sorbitol.
- Chen, Zhe-Ning,Clark, James H.,Duan, Sai,Liu, Yaoqi,Shen, Lingyun,Sun, Zheming,Tu, Tao,Wu, Jiajie,Xu, Xin,Zheng, Qingshu
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supporting information
p. 13871 - 13878
(2020/06/08)
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- Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate
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Two-dimensional (2D) transition metal nanosheets are promising catalysts because of the enhanced exposure of the active species compared to their 3D counterparts. Here, we report a simple, scalable, and reproducible strategy to prepare 2D phosphate nanosheets by forming a layered structure in situ from phytic acid (PTA) and transition metal precursors. Controlled combustion of the organic groups of PTA results in interlayer carbon, which keeps the layers apart during the formation of phosphate, and the removal of this carbon results in ultrathin nanosheets with controllable layers. Applying this concept to vanadyl phosphate synthesis, we show that the method yields 2D ultrathin nanosheets of the orthorhombic β-form, exposing abundant V4+/V5+ redox sites and oxygen vacancies. We demonstrate the high catalytic activity of this material in the vapor-phase aerobic oxidation of ethyl lactate to ethyl pyruvate. Importantly, these β-VOPO4 compounds do not get hydrated, thereby reducing the competing hydrolysis reaction by water byproducts. The result has superior selectivity to ethyl pyruvate compared to analogous vanadyl phosphates. The catalysts are highly stable, maintaining a steady-state conversion of ~90% (with >80% selectivity) for at least 80 h on stream. This "self-exfoliated" synthesis protocol opens opportunities for preparing structurally diverse metal phosphates for catalysis and other applications.
- Li, Lain-Jong,Oulego, Paula,Rothenberg, Gadi,Sharma, Sandeep K.,Shiju, N. Raveendran,Yang, Xiu-Lin,Zhang, Wei
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p. 3958 - 3967
(2020/05/05)
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- Selective oxidation of 1,2-propanediol to lactic acid over Cu-modified Au/hydrotalcite catalysts
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Catalytic oxidation of biomass-derived 1,2-propanediol to valuable lactic acid was investigated over various Cu-modified Au supported on Mg-Al hydrotalcite (HT). Compared to those of individual Au-HT, better catalytic performance was achieved over the Cu-modified Au-HT catalysts, mainly due to the suppression of by-product generation. The structural properties of the Cu-Au/HT catalysts were determined by XRD, SEM, HRTEM, and N2 physical adsorption, and a strong interaction was discovered in the Cu-modified Au-HT catalysts. A control experiment verified that the secondary hydroxyl in 1,2-propanediol is unreactive over Au/HT catalysts modified with Cu, which intensively inhibited the generation of the main by-products, formic acid and acetic acid. These findings provided useful guidance for the design of more efficient and stable nano-catalysts for oxidizing glycols to organic acids containing hydroxides.
- Tian, Junying,Liu, Hailong,Li, Ping,Huang, Zhiwei,Chen, Jing
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p. 16311 - 16319
(2020/10/14)
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- Selective hydrogenolysis of biomass-derived sorbitol to propylene glycol and ethylene glycol on in-situ formed PdZn alloy catalysts
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Sorbitol hydrogenolysis to industrially important propylene glycol and ethylene glycol receives increasing attention, recently. Here, we developed an efficient and stable PdZn alloy catalyst, in-situ formed from a physical mixture of Pd/ZrO2 and ZnO, for the sorbitol hydrogenolysis with Mg3AlOx as a solid base, and obtained a 54.6% yield of the two target glycols (493 K and 5.0 MPa H2). The amounts of ZnO and Mg3AlOx strongly influenced the activity and selectivity, due to their effects on the formation of the PdZn alloys and the competitive metal-catalyzed dehydrogenation/hydrogenation and base-catalyzed retro-aldol condensation steps. The kinetic isotope effects, combined with the inhibiting effects of H2 pressure on the activity in a broad range (3.0–8.0 MPa), confirm that the sorbitol dehydrogenation to hexose intermediates is the kinetically-relevant step in the sorbitol hydrogenolysis. This study provides insights into the catalytic functions and reaction parameters for the hydrogenolysis of polyols to the target glycols.
- Jia, Yuqing,Liu, Haichao,Sun, Qianhui
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- Multiporous Carbon Encapsulated Ni Nanoparticles Promoting Glycerol Valorisation towards Hydrogenation against Rearrangement?
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A dual-templating method was used to synthesize a series of hierarchical carbon supports containing different proportions of spherical macropores (ca. 200 nm in diameter) and mesoporous channels (ca. 4 nm in diameter). These and some other conventional carbon materials were subsequently impregnated with Ni and tested for the conversion of glycerol. The hierarchical catalysts exhibited a significantly higher conversion (96%) and selectivity (77%) to 1,2-propanediol, and the specificity selectivity coefficient (6.1) towards 1,2-propanediol against lactic acid was three times higher than that observed over a conventional Ni/Cmicro catalyst (2.1). The enhanced performance of these materials, compared with the Ni nanoparticles supported on conventional carbon supports, was attributed to their high surface areas (> 1110 m2?g?1) and large pore volumes (ca. 0.4 cm3?g?1) permitting greater accessibility of substrate and/or intermediates to Ni active sites. Given that the concentration of accessible Ni sites in these materials is higher, a competitive benzilic-acid-rearrangement reaction to produce lactic acid was suppressed, leading to an enhanced hydrogenation selectivity to 1,2-propanediol. This study evidences the potential benefits, which can be established from utilizing hierarchical support materials in the valorization of biomass.
- Chen, Bin,Douthwaite, Mark,Ma, Ding,Tang, Lipeng,Wang, Meng,Zhang, Bin,Zhang, Yibo
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p. 439 - 444
(2020/04/20)
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- Glycerol Selective Oxidation to Lactic Acid over AuPt Nanoparticles; Enhancing Reaction Selectivity and Understanding by Support Modification
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A high surface area mesoporous TiO2 material (110 m2/g) was synthesised using a nanocasting methodology, utilizing SBA-15 as a hard template. This material was subsequently used as a support to prepare a series of 1 wt.% AuPt/TiO2 catalysts, synthesised by conventional impregnation and sol-immobilisation. Catalysts were tested for the oxidation of glycerol to lactic acid and their performance was compared with corresponding catalysts supported on TiO2?P25, TiO2-anatase and TiO2-rutile. Higher rates of reaction and higher selectivity to lactic acid were observed over nanocast TiO2 supported catalysts. The increased performance of these catalysts was attributed to the presence of Si on the surface of the support, which likely arose from inefficient etching of the SBA-15 template. The presence of Si in these catalysts was confirmed by X-ray photoelectron spectroscopy and electron energy loss spectroscopy. It was proposed that the residual Si present increases the Br?nsted acidity of the TiO2 support, which can lead to the formation of Lewis acid sites under reaction conditions; both sites are known to catalyse the dehydration of a primary alcohol in glycerol. Typically, under alkaline conditions, lactic acid is formed by the nucleophilic abstraction of a hydrogen. Thus, we propose that the improved selectivity to lactic acid over the nanocast TiO2 supported catalyst is attributed to the co-operation of heterogeneous and homogeneous dehydration reactions, as both compete directly with a direct oxidation pathway, which leads to the formation of oxidation products such as glyceric and tartronic acid.
- Douthwaite, Mark,Ford, Grayson,Garcia, Tomas,He, Qian,López, José Manuel,Morgan, David J.,Powell, Natasha,Sanahuja-Parejo, Olga,Solsona, Benjamin,Taylor, Aoife,Taylor, Stuart H.,Yang, Nating
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- Bimetallic Cu?Zn Co-Doped Porous N/C as Efficient Catalysts for Oxygen Reduction Reaction and Oxidation of 1,2-Propanediol
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The development of non-precious metal catalysts toward oxygen reduction reaction (ORR) is essential for widespread application of fuel cells. Herein, bimetallic Cu?Zn co-doped porous N/C catalysts (Cu?Zn?N/C) with high N content were synthesized via a simple metal-organic framework (MOF)-derived method. The as-prepared Cu?Zn?N/C catalyst presents superior catalytic activity toward ORR with an onset potential of 0.90 V, a half-wave potential of 0.79 V, and a diffusion limiting current density of 5.82 mA cm?2. It is found that Cu exists in three forms: one exists in Cu particles, and the others exist in Cu single atoms (either in high valence or in zero valence) that embedded in the carbon substrate. The evaporation of Zn atoms during the pyrolysis induces the pore structure of the carbon matrix, making it possible to support for the zero valent Cu atoms. In addition, as an efficient Cu-based catalyst for many applications, we show that the as-prepared catalyst can selectively oxidize 1,2-propanediol to lactic acid with 75.7 % selectivity at 82.8 % conversion.
- Yang, Li-Ping,Mi, Jian-Li,Wang, Hui-Jie,Liang, Jia-Hao,Yang, Xue-Jing,Feng, Yong-Hai,Zhang, Peng,Liu, Lu
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p. 584 - 592
(2019/11/14)
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- Oxidation of 1,2-propanediol to carboxylic acid over hydroxyapatite nanorod-supported metallic Cu0 nanoparticles
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Hydroxyapatite nanorod-supported metallic Cu0 nanoparticle catalysts (Cux/HAP) were prepared by the wetness chemical reduction method. The metallic Cu0 nanoparticles were well dispersed on the surfaces of the HAP nanorods. The alkaline HAP nanorods inhibited the crystal growth of the metallic Cu0 nanoparticles. The HAP nanorods also retarded the oxidation of the metallic Cu0 nanoparticles. The Cux/HAP catalyst exhibited a higher catalytic activity for the oxidation of 1,2-propanediol with gaseous oxygen to lactic, acetic, and formic acids with the total selectivity of 70.3% even at a lower reaction temperature of 140 °C. The total selectivity of lactic, acetic, and formic acids reached 93.1% at a mild reaction temperature of 180 °C. However, the sole monometallic Cu0 nanoparticles or HAP nanorods had no catalytic activity for the oxidation of 1,2-propanediol. The metallic Cu0 nanoparticles and alkaline HAP nanorods in the Cux/HAP catalyst synergistically catalyzed the oxidation of 1,2-propanediol to carboxylic acid.
- Qiu, Lang,Shen, Lingqin,Tao, Wei,Wang, Aili,Yin, Hengbo
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p. 1723 - 1731
(2020/01/21)
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- PtRu/Zn3Ce1Oxcatalysts with Lewis acid-base pairs show synergistic performances for the conversion of glycerol in the absence of externally added H2
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Previous studies revealed that tandem dehydration, dehydrogenation and hydrogenation, promoted by metal-support interfacial catalysis, play a critical role in determining the intrinsic kinetics of transfer hydrogenolysis of bio-oxygenates. However, the synergism of metal and acid-base pairs for tunable C-H, O-H and C-O cleavage and metal-H strength is under debate in this area. Herein, we present a series of bimetallic PtRu/Zn3Ce1-LDO catalysts, with abundant Lewis acid-base pairs and heterojunction structures at the metal-support interface, exhibiting enhanced performances of transfer hydrogenolysis of glycerol. The key finding is that the incorporation of ZnO unexpectedly induced the formation of large amounts of oxygen vacant sites and surface hydroxyl sites on the CeOx support, leading to abundant Lewis acid-base pairs. The strong electron coupling effect of PtRu and Lewis acid-base pairs results in weakened PtRu-H bonding, facilitating a hydrogen transfer reaction. Synergism between enhanced Lewis acid-base pairs and weaker PtRu-H hydride bonding is critical for remarkable catalytic activity (TOF: 526 h-1) and selectivity towards glycols (70.8percent), and results in one of the best performances in the current literature. Moreover, the influence of hydrogen donors, reaction temperature and time on conversion and product distribution was further investigated in detail. An alternative reaction pathway for the transfer hydrogenolysis of glycerol over the proposed acid-base pair catalysts was proposed and validated with experimental data. The outcome of this work will provide new insights into the rational design of efficient catalytic materials for energy and environmental applications.
- Chen, Xiaobo,Cheng, Yinlei,Feng, Xiang,Jin, Xin,Liu, Yibin,Yang, Chaohe,Zhang, Guangyu,Zhang, Quanxing
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p. 4386 - 4395
(2020/07/30)
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- Toward glucuronic acid through oxidation of methyl-glucoside using PdAu catalysts
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The production of glucuronic acid via enzyme catalysis from biomass is slow. Here we studied the oxidation of methoxy-protected glucose (MG) using Pd-on-Au nanoparticle model catalysts to generate methoxy-protected glucuronic acid (MGA), a precursor to glucuronic acid. Pd-on-Au showed volcano-shape activity dependence on calculated Pd surface coverage (sc). The 80 sc% Pd-on-Au catalyst composition showed maximum initial turnover frequency (413 mol-MG mol-surface-atom?1 h?1) that was 5× higher than that of Au/C, while Pd/C was inactive. This Pd-on-Au composition gave the highest MGA yield (46%), supporting a bimetallic approach to glucuronic acid production.
- Yin, Y. Ben,Chen, Li,Heck, Kimberly N.,Zhang, Z. Conrad,Wong, Michael S.
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- Transfer hydrogenation of levulinic acid from glycerol and ethanol using water-soluble iridium N-heterocyclic carbene complexes
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The upgrading of biomass derivatives to biofuels and chemicals through transfer hydrogenation (TH) is attractive relative to direct hydrogenation, especially when the hydrogen donors can be sourced renewably. Here we report the first process that uses glycerol, a renewable waste material from biodiesel processing, as a hydrogen donor in the catalytic TH of a biomass-derived platform chemical, levulinic acid, to selectively afford γ-hydroxyvaleric acid (GHV) and lactic acid (LA). GHV can be further converted to γ-valerolactone (GVL), a widely used platform chemical. Levulinic acid can be used directly, without esterification, which is typically needed for transfer hydrogenation. The process is efficiently facilitated by robust iridium N-heterocyclic carbene (NHC) complexes with sulfonate functional groups at low catalyst loading (1–10 ppm), affording quantitative conversion of levulinic acid in the presence of KOH to GHV, with >100,000 TON in 2 h at 150 °C, using 1 ppm catalyst. The most prolific catalyst, [(NHC-SO3-)2(CO)2Ir]Na, can also facilitate transfer hydrogenation from other hydrogen donors, such as 2-propanol, potassium formate, and most notably, ethanol, which can also be derived from renewables. Ethanol is a highly efficient hydrogen donor for levulinic acid using this catalyst, affording >7,000 turnovers in 2 h using 10 ppm catalyst.
- Culley, Keira,Heltzel, Jacob,Lemcoff, Gabriel,Sandefur, Evan,Voutchkova-Kostal, Adelina,Wang, Kai
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supporting information
(2020/05/18)
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- Method for preparing lactic acid
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The invention relates to a method for preparing lactic acid. The method comprises the following steps: contacting sugar and water with a catalyst in a reactor, and reacting to obtain a product containing lactic acid, wherein the molar ratio of the sugar to the water is 1:(50-1600), 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 dry basis weight is 1:(0.1-6). The method provided by the invention has high sugar conversion rate and high lactic acid yield.
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Paragraph 0069-0100
(2020/07/02)
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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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