849585-22-4Relevant articles and documents
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
Duo, Jia,Jin, Binbin,Jin, Fangming,Shi, Xiaoyu,Wang, Tianfu,Ye, Xin,Zhong, Heng
, p. 813 - 822 (2022/02/09)
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.
Acceptorless dehydrogenation of primary alcohols to carboxylic acids by self-supported NHC-Ru single-site catalysts
Yin, Shenxiang,Zheng, Qingshu,Chen, Jie,Tu, Tao
, p. 165 - 172 (2022/03/23)
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.
Catalytic wet air oxidation of D-glucose by perovskite type oxides (Fe, Co, Mn) for the synthesis of value-added chemicals
Geobaldo, Francesco,Pirone, Raffaele,Russo, Nunzio,Scelfo, Simone
, (2022/03/15)
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
Ce promoted Cu/γ-Al2O3 catalysts for the enhanced selectivity of 1,2-propanediol from catalytic hydrogenolysis of glucose
Balachandran Kirali, Arun Arunima,Marimuthu, Banu,Sreekantan, Sreejith
, (2022/03/31)
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.
The selective oxidation of glycerol over metal-free photocatalysts: insights into the solvent effect on catalytic efficiency and product distribution
Fan, Mingming,Haryonob, Agus,Jiang, Pingping,Leng, Yan,Yue, Chengguang,Zhang, Pingbo
, p. 3385 - 3392 (2021/06/06)
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.
Catalytic isomerization of dihydroxyacetone to lactic acid by heat treated zeolites
Dong, Jie,Hossain, Md Anwar,Lalvani, Shashi B.,Mills, Kyle N.,Molley, Ashten M.,Rahaman, Mohammad Shahinur,Sathitsuksanoh, Noppadon,Sunkara, Mahendra K.,Tulaphol, Sarttrawut
, (2021/01/05)
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.
METHODS FOR SYNTHESIZING ANHYDROUS LACTIC ACID
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Paragraph 0038; 0055, (2021/11/13)
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.
Effect of physicochemical parameters on the stability and activity of garlic alliinase and its use for in-situ allicin synthesis
Janska, Petra,Knejzlík, Zdenek,Perumal, Ayyappasamy Sudalaiyadum,Jurok, Radek,Tokarova, Viola,Nicolau, Dan V.,Tepanek, FrantisekS,Kaspar, Ondrej
, (2021/03/26)
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.
Parahydrogen-Induced Polarization Relayed via Proton Exchange
Them, Kolja,Ellermann, Frowin,Pravdivtsev, Andrey N.,Salnikov, Oleg G.,Skovpin, Ivan V.,Koptyug, Igor V.,Herges, Rainer,H?vener, Jan-Bernd
supporting information, p. 13694 - 13700 (2021/09/07)
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.
GNCC AND/OR PCC AS A CATALYTIC CARRIER FOR METAL SPECIES
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Page/Page column 31-32, (2021/04/02)
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.
