- Synthesis and reactivity of iron complexes with a new pyrazine-based pincer ligand, and application in catalytic low-pressure hydrogenation of carbon dioxide
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A novel pincer ligand based on the pyrazine backbone (PNzP) has been synthesized, (2,6-bis(di(tert-butyl)phosphinomethyl)pyrazine), tBu-PNzP. It reacts with FeBr2 to yield [Fe(Br)2(tBu-PNzP)], 1. Treatment of 1 with NaBH4 in MeCN/MeOH gives the hydride complex [Fe(H)(MeCN)2(tBu-PNzP)][X] (X = Br, BH4), 2·X. Counterion exchange and exposure to CO atmosphere yields the complex cis-[Fe(H)(CO)(MeCN)(tBu-PNzP)][BPh4] 4·BPh4, which upon addition of Bu4NCl forms [Fe(H)(Cl)(CO)(tBu-PNzP)] 5. Complex 5, under basic conditions, catalyzes the hydrogenation of CO2 to formate salts at low H2 pressure. Treatment of complex 5 with a base leads to aggregates, presumably of dearomatized species B, stabilized by bridging to another metal center by coordination of the nitrogen at the backbone of the pyrazine pincer ligand. Upon dissolution of compound B in EtOH the crystallographically characterized complex 7 is formed, comprised of six iron units forming a 6-membered ring. The dearomatized species can activate CO2 and H2 by metal-ligand cooperation (MLC), leading to complex 8, trans-[Fe(PNzPtBu-COO)(H)(CO)], and complex 9, trans-[Fe(H)2(CO)(tBu-PNzP)], respectively. Our results point at a very likely mechanism for CO2 hydrogenation involving MLC.
- Rivada-Wheelaghan, Orestes,Dauth, Alexander,Leitus, Gregory,Diskin-Posner, Yael,Milstein, David
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- Iron-catalyzed hydrogenation of bicarbonates and carbon dioxide to formates
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The catalytic hydrogenation of carbon dioxide and bicarbonate to formate has been explored extensively. The vast majority of the known active catalyst systems are based on precious metals. Herein, we describe an effective, phosphine-free, airand moisture-
- Zhu, Fengxiang,Zhu-Ge, Ling,Yang, Guangfu,Zhou, Shaolin
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- Selective reduction of CO2 to formate through bicarbonate reduction on metal electrodes: New insights gained from SG/TC mode of SECM
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We discovered using SECM of the electro-reduction of CO2 on a Au substrate in CO2-saturated KHCO3 solutions that (i) formate comes solely from the direct reduction of bicarbonate; and (ii) CO forms only from CO2 reduction (under low pH conditions) and at higher applied potentials. The results point to the possibility of the selective reduction of CO2 to the formate product.
- Sreekanth, Narayanaru,Phani, Kanala Lakshminarasimha
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- Catena-Poly[disodium [[diformato-tricopper(II)]-di-μ3- formato-tetra-μ2-formato]]: A new mode of bridging between binuclear and mononuclear formate-copper(II) units
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The novel title polymeric copper(II) complex, {Na2[Cu 3-(CHO2)8]}n, consists of sodium cations and infinite anionic chains, in which neutral dinuclear [Cu 2(O2CH)4] moieties alternate with dianionic [Cu(O2CH)4]2- units. Both metal-containing moieties are located on crystallographic inversion centers. The syn-syn bridging configuration between the mononuclear and dinuclear components yields a structure that is significantly more dense than the structures previously reported for mononuclear-dinuclear copper(II) carboxylates with syn-anti or anti-anti bridging modes.
- Golobic, Amalija,Malekovic, Martina,Segedin, Primoz
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- Formaldehyde Electro-oxidation on Copper Metal and Copper-based Amorphous Alloys in Alkaline Media
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Copper metal and copper-based amorphous alloys, a-Cu35Ti65 and a-Cu33Zr67, exhibit a very high and stable activity for the anodic HCHO oxidation in aqueous NaOH and Na2CO3.The oxidation current was atready observable at electrode potentials as low as 0.1 V (RHE) and, in particular, the HF-treated amorphous alloys gave high current densities around 40 mA cm-2 (apparent) at 0.2 V.Kinetic data, roughly first order both in HCHO and OH(1-) concentration, are in favour of the mechanism in which the oxidation proceeds via hydroxymethanolate ion (HOCH2O(1-)) formed from HCHO and OH(1-), producing HCOO(1-) and H2: This ion is readily oxidized on the copper metal or copper-based amorphous alloy electrodes.The Tafel slope was in general agreement with the reaction mechanism assuming a rate-determining one-electron transfer step.
- Machida, Ken-ichi,Enyo, Michio
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- Mesoporous Silica-Encaged Ultrafine Bimetallic Nanocatalysts for CO2 Hydrogenation to Formates
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CO2 hydrogenation to formic acid/formate has been recognized as a key reaction to realizing the CO2-mediated hydrogen energy cycle. Herein, ultrafine and well-dispersed Pd?CoO nanoparticles (~1.8 nm) were encapsulated within mesoporous silica nanospheres (MSNs) via a facile one-pot ligand-protected synthesis strategy. The MSN-encaged bimetallic nanocatalysts exhibit excellent catalytic activity and stability for the formate production from CO2 hydrogenation, showing high turnover frequency value up to 1824 h?1 at 373 K, which is among the top-level reported for heterogeneous catalysts.
- Sun, Qiming,Fu, Xinpu,Si, Rui,Wang, Chi-Hwa,Yan, Ning
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- Molecular H2O promoted catalytic bicarbonate reduction with methanol into formate over Pd0.5Cu0.5/C under mild hydrothermal conditions
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Direct reduction of bicarbonate, a typical product of CO2 captured in alkaline solution, into value-added organics is one promising way to achieve a simplified and green CO2 capture and utilization process. In this work, a new strategy of bicarbonate reduction coupled with methanol oxidation into a dual formation of formate under mild hydrothermal conditions is reported. A 68% formate production efficiency based on the reductant methanol and nearly 100% selectivity of formate were obtained via a Pd0.5Cu0.5/C catalyst at 180 °C. An operando hydrothermal ATR-FTIR study proved that the bicarbonate was reduced by the in situ generated hydrogen from methanol, which was stepwise oxidized to formaldehyde and formic acid. Notably, DFT calculations and a qNMR study of the 13C and 2H (D) isotopic labelling revealed that H2O molecules not only supplied the hydrogen for bicarbonate reduction but also acted as an indispensable promoter to enhance the catalytic performance of Pd0.5Cu0.5/C for methanol activation.
- Wang, Xiaoguang,Yang, Yang,Zhong, Heng,Wang, Tianfu,Cheng, Jiong,Jin, Fangming
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- A MOF-assisted phosphine free bifunctional iron complex for the hydrogenation of carbon dioxide, sodium bicarbonate and carbonate to formate
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The hydrogenation of carbon dioxide into formic acid (FA) with Earth-abundant metals is a vibrant research area because FA is an attractive molecule for hydrogen storage. We report a cyclopentadienyl iron tricarbonyl complex that provides up to 3000 turnover number for carbon dioxide hydrogenation when combined with a catalytic amount of the chromium dicarboxylate MOF MIL-53(Cr). To date, this is the highest turnover number reported in the presence of a phosphine-free iron complex.
- Coufourier, Sébastien,Gaillard, Sylvain,Clet, Guillaume,Serre, Christian,Daturi, Marco,Renaud, Jean-Luc
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- An amino acid based system for CO2capture and catalytic utilization to produce formates
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Herein, we report a novel amino acid based reaction system for CO2 capture and utilization (CCU) to produce formates in the presence of the naturally occurring amino acid l-lysine. Utilizing a specific ruthenium-based catalyst system, hydrogenation of absorbed carbon dioxide occurs with high activity and excellent productivity. Noteworthy, following the CCU concept, CO2 can be captured from ambient air in the form of carbamates and converted directly to formates in one-pot (TON > 50?000). This protocol opens new potential for transforming captured CO2 from ambient air to C1-related products.
- Wei, Duo,Junge, Henrik,Beller, Matthias
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- CO2 reduction with protons and electrons at a boron-based reaction center
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Borohydrides are widely used reducing agents in chemical synthesis and have emerging energy applications as hydrogen storage materials and reagents for the reduction of CO2. Unfortunately, the high energy cost associated with the multistep preparation of borohydrides starting from alkali metals precludes large scale implementation of these latter uses. One potential solution to this issue is the direct synthesis of borohydrides from the protonation of reduced boron compounds. We herein report reactions of the redox series [Au(B2P2)]n (n = +1, 0, -1) (B2P2, 9,10-bis(2-(diisopropylphosphino)phenyl)-9,10-dihydroboranthrene) and their conversion into corresponding mono- and diborohydride complexes. Crucially, the monoborohydride can be accessed via protonation of [Au(B2P2)]-, a masked borane dianion equivalent accessible at relatively mild potentials (-2.05 V vs. Fc/Fc+). This species reduces CO2 to produce the corresponding formate complex. Cleavage of the formate complex can be achieved by reduction (ca. -1.7 V vs. Fc/Fc+) or by the addition of electrophiles including H+. Additionally, direct reaction of [Au(B2P2)]- with CO2 results in reductive disproportion to release CO and generate a carbonate complex. Together, these reactions constitute a synthetic cycle for CO2 reduction at a boron-based reaction center that proceeds through a B-H unit generated via protonation of a reduced borane with weak organic acids.
- Taylor, Jordan W.,McSkimming, Alex,Essex, Laura A.,Harman, W. Hill
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- Nanoporous Ag-Sn derived from codeposited AgCl-SnO2 for the electrocatalytic reduction of CO2 with high formate selectivity
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Nanoporous Ag-Sn was prepared by direct electroreduction of a codeposited AgCl-SnO2 mixture in 0.1 M HCl, and evaluated as an electrode catalyst for the reduction of CO2 in 0.5 M KHCO3. A volcano-type correlation between selectivity for the formate product and the atomic ratio of Ag to Sn in the nanoporous catalysts was revealed. It was found that the bimetallic catalyst with a Ag:Sn ratio of 3:2, mainly composed of the Ag4Sn alloy, showed excellent catalytic performance for the conversion of CO2 to formate. This catalyst delivered a current of about 10 mA cm?2 with a high formate faradaic efficiency of about 85% at ?0.8 V vs. the reversible hydrogen electrode. Moreover, the catalytic activity remained reasonably stable during a 13.5-hour electrolysis.
- Wang, Xiaoyan,Xiao, Wei,Zhang, Jichen,Wang, Zhiyong,Jin, Xianbo
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- Carbon nanoparticles as visible-light photocatalysts for efficient CO 2 conversion and beyond
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Increasing atmospheric CO2 levels have generated much concern, driving the ongoing carbon sequestration effort. A compelling CO2 sequestration option is its photocatalytic conversion to hydrocarbons, for which the use of solar irradiation represents an ultimate solution. Here we report a new strategy of using surface-functionalized small carbon nanoparticles to harvest visible photons for subsequent charge separation on the particle surface in order to drive the efficient photocatalytic process. The aqueous solubility of the catalysts enables photoreduction under more desirable homogeneous reaction conditions. Beyond CO2 conversion, the nanoscale carbon-based photocatalysts are also useful for the photogeneration of H 2 from water under similar conditions.
- Cao, Li,Sahu, Sushant,Anilkumar, Parambath,Bunker, Christopher E.,Xu, Juan,Fernando, K. A. Shiral,Wang, Ping,Guliants, Elena A.,Tackett, Kenneth N.,Sun, Ya-Ping
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- Ligand assisted carbon dioxide activation and hydrogenation using molybdenum and tungsten amides
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The hepta-coordinated isomeric M(NO)Cl3(PNHP) complexes {M = Mo, 1a(syn,anti); W, 1b(syn,anti), PNHP = (iPr2PCH2CH2)2NH, (HN atom of PNHP syn and anti to the NO ligand)} and the paramagnetic species M(NO)Cl2(PNHP) (M = Mo, 2a(syn,anti); W, 2b(syn,anti)) could be prepared via a new synthetic pathway. The pseudo trigonal bipyramidal amides M(NO)(CO)(PNP) {M = Mo, 3a; W, 3b; [PNP]- = [(iPr2PCH2CH2)2N]-} were reacted with CO2 at room temperature with CO2 approaching the MN double bond in the equatorial (CO,NO,N) plane trans to the NO ligand and forming the pseudo-octahedral cyclic carbamates M(NO)(CO)(PNP)(OCO) (M = Mo, 4a(trans); W = 4b(trans)). DFT calculations revealed that the approach to form the 4b(trans) isomer is kinetically determined. The amine hydrides M(NO)H(CO)(PNHP) {M = Mo, 5a(cis,trans); W, 5b(cis,trans)}, obtained by H2 addition to 3a,b, insert CO2 (2 bar) at room temperature into the M-H bond generating isomeric mixtures of the η1-formato complexes M(NO)(CO)(PNHP)(η1-OCHO), (M = Mo, 6a(cis,trans); M = W, 6b(cis,trans)). Closing the stoichiometric cycles for sodium formate formation the 6a,b(cis,trans) isomeric mixtures were reacted with 1 equiv. of Na[N(SiMe3)2] regenerating 3a,b. Attempts to turn the stoichiometric formate production into catalytic CO2 hydrogenation using 3a,b in the presence of various types of sterically congested bases furnished yields of formate salts of up to 4%. This journal is
- Chakraborty, Subrata,Blacque, Olivier,Berke, Heinz
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- A Carbon-Neutral CO2 Capture, Conversion, and Utilization Cycle with Low-Temperature Regeneration of Sodium Hydroxide
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A highly efficient recyclable system for capture and subsequent conversion of CO2 to formate salts is reported that utilizes aqueous inorganic hydroxide solutions for CO2 capture along with homogeneous pincer catalysts for hydrogenation. The produced aqueous solutions of formate salts are directly utilized, without any purification, in a direct formate fuel cell to produce electricity and regenerate the hydroxide base, achieving an overall carbon-neutral cycle. The catalysts and organic solvent are recycled by employing a biphasic solvent system (2-MTHF/H2O) with no significant decrease in turnover frequency (TOF) over five cycles. Among different hydroxides, NaOH and KOH performed best in tandem CO2 capture and conversion due to their rapid rate of capture, high formate conversion yield, and high catalytic TOF to their corresponding formate salts. Among various catalysts, Ru- and Fe-based PNP complexes were the most active for hydrogenation. The extremely low vapor pressure, nontoxic nature, easy regenerability, and high reactivity of NaOH/KOH toward CO2 make them ideal for scrubbing CO2 even from low-concentration sources - such as ambient air - and converting it to value-added products.
- Kar, Sayan,Goeppert, Alain,Galvan, Vicente,Chowdhury, Ryan,Olah, Justin,Prakash, G. K. Surya
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- Facile hydrogenation of bicarbonate to formate in aqueous medium by highly stable nickel-azatrane complex
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Molecular catalyst-based direct hydrogenation of bicarbonate to formate in aqueous medium is a challenging research topic for the H2 storage. Finding a green and effective method for the bicarbonate to formate conversion with non-precious metal-based catalyst is vital to the practical application. We report the direct hydrogenation of bicarbonate to formate using a water soluble nickel-azatrane complex. Catalysts 1–5, designed and synthesized, were screened for the hydrogenation of bicarbonate to formate in aqueous medium; the best TON of 121 was obtained for catalyst 4 at 120 °C (60 bar). Introduction of isopropyl (2) and methyl (3 and 4) groups in the coordination environment of the metal center enhances the production of formate. Further, the hydrogenation of bicarbonate with CO2 promoted the formate production for catalyst 4 with a TON of 92 (3 h). The use of green solvent and non-precious metal catalyst makes this catalytic method environmentally sustainable.
- Sivanesan, Dharmalingam,Seo, Bongkuk,Lim, Choong-Sun,Kim, Hyeon-Gook
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- Efficient and Mild Carbon Dioxide Hydrogenation to Formate Catalyzed by Fe(II) Hydrido Carbonyl Complexes Bearing 2,6-(Diaminopyridyl)diphosphine Pincer Ligands
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Fe(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were found to promote the catalytic hydrogenation of CO2 and NaHCO3 to formate in protic solvents in the presence of bases, r
- Bertini, Federica,Gorgas, Nikolaus,St?ger, Berthold,Peruzzini, Maurizio,Veiros, Luis F.,Kirchner, Karl,Gonsalvi, Luca
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- Conversion of CO2 from air into formate using amines and phosphorus-nitrogen PN3P-Ru(ii) pincer complexes
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Well-defined ruthenium(ii) PN3P pincer complexes were developed for the hydrogenation of carbon dioxide. Excellent product selectivity and catalytic activity with TOF (turnover frequency) and TON (turnover number) up to 13000 h-1 and 33000, respectively, in a THF/H2O biphasic system were achieved. Notably, effective conversion of carbon dioxide from air into formate was conducted in the presence of an amine, allowing easy product separation and catalyst recycling.
- Guan, Chao,Pan, Yupeng,Ang, Eleanor Pei Ling,Hu, Jinsong,Yao, Changguang,Huang, Mei-Hui,Li, Huaifeng,Lai, Zhiping,Huang, Kuo-Wei
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- Cu AND Cu-BASED AMORPHOUS ALLOY ELECTRODES FOR ANODIC FORMALDEHYDE ELECTRO-OXIDATION
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The electrodes of Cu and Cu-based amorphous alloys, a-Cu35Ti65 and a-Cu33Zr67, were very active for the HCHO electro-oxidation in alkaline solutions.The oxidation started at electrode potentials as low as 0.1 V (RHE) and the HF-treated amorphous alloys exhibited high current densities around 40 mA cm-2 (app.) at 0.2 V.
- Machida, Ken-ichi,Enyo, Michio
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- New Ru(ii) N′NN′-type pincer complexes: synthesis, characterization and the catalytic hydrogenation of CO2 or bicarbonates to formate salts
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[RuCl(L1)(MeCN)2]Cl (1) and [RuCl(L2)(MeCN)2]Cl (2) complexes were prepared through the reaction of [RuCl2(p-cymene)]2 with 2,6-bis(benzimidazole-2-yl)-4-hydroxy-pyridine (L1) or 2,6-bis(benzimidazole-2-yl) pyridine (L2) in acetonitrile, respectively. The treatment of [Ru(OTf)(L2)(MeCN)2]OTf (3) with 1 equivalent of PPh3 in ethanol resulted in the formation of [Ru(L2-1)(MeCN)(PPh3)2]OTf (4), in which one of the N-H moieties of L2 is deprotonated to give an anionic ligand (L2-1). It was found that complex 1 can catalyze the hydrogenation of CO2 to formate salts, producing sodium formate in 34.0% yield with a turnover number (TON) of 407 under the optimized conditions. Further investigations revealed that complexes 1-4 can efficiently catalyze the hydrogenation of sodium bicarbonate to sodium formate, and the catalytic activity follows the order 4 > 1 > 2 ≈ 3. In particular, sodium formate was obtained in good yield (77%) with a high TON (1530) when complex 4 was used as the catalyst. The present results illustrate a new example of Ru(ii) complexes bearing a rigid N′NN′ framework for the efficient hydrogenation of CO2 to formate salts in a homogeneous system.
- Dai, Zengjin,Luo, Qi,Cong, Hengjiang,Zhang, Jing,Peng, Tianyou
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- Direct Formation of Formic Acid from Carbon Dioxide and Dihydrogen using the 2>-Ph2P(CH2)4PPh2 Catalyst System
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Formic acid, isolable as sodium formate from the reaction mixture, is produced directly from hydrogen and carbon dioxide with yields up to 1150 moles per mole of rhodium using a homogeneous catalyst formed in situ from 2> and Ph2P(CH2)4PPh2; the precious metal is recovered during work-up in a catalytically active form.
- Graf, Elisabeth,Leitner, Walter
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- Novel Mechanism for Oxidative Cleavage of Glycosidic Bonds: Evidence for an Oxygen Dependent Reaction
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In a previous work from our laboratory, an optimized procedure was worked out for cleavage of the glucosidic bonds in ginsenosides (Cui, J.F.; Garle, M.; Lund, E.; Bjoerkhem, I.; Eneroth, P.Anal.Biochem. 1993, 210, 411-417).When the reaction was performed in n-butanol, alkaline conditions were found to give a considerably better and almost quantitative yield of intact aglyconic-specific products than did acidic conditions.This is surprising in view of the current concept that glucosidic bonds are more stable under alkaline than acidic conditions.It is shown here that the alkaline cleavage is oxygen dependent and that there is little or no conversion when oxygen or air is replaced with nitrogen.Addition of an anti-oxidant, glucose or water also reduces the degree of cleavage under the conditions employed.Replacement of n-butanol for sec-, iso- or 2-methyl-2-propanol, decreased the yield of products to about 75percent and when n- or isopropanol was used as solvent the yield decreased to about 40percent.It was shown that the glucose moiety was completely degraded under the conditions employed and that formate and carbonate, in a ratio of 5/1, were the major products.A mechanistic rationale for the oxygen dependent cleavage of the glucosidic bonds is suggested.The possibility that this mechanism may be of protective importance in biological systems under some specific conditions is also discussed.
- Cui, Jian-Fang,Bystroem, Styrbjoern,Eneroth, Peter,Bjoerkhem, Ingemar
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- Kinetic Analysis of Electroless Deposition of Copper
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Kinetic data on elelctroless copper deposition from a formaldehyde/EDTA solution are analyzed and discussed in terms of a formal kinetic rate law.The derived rate equation shows first-order dependence on the methylene glycol anion and zeroth order on cupric ion.Kinetic preexponential factors evaluated from temperature dependencies of reaction rates indicate that the rate-determining step involves an adsorbed species.A primary kinetic isotope effect kH/kD = 5 upon substitution of deuterium for protium in formaldehyde indicates that cleavage of the carbon-hydrogen bond of the adsorbed methylene glycol anion is rate determining.
- Schumacher, R.,Pesek, J. J.,Melroy, O. R.
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- Towards a sustainable synthesis of formate salts: Combined catalytic methanol dehydrogenation and bicarbonate hydrogenation
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Formate salts are important chemicals widely used in everyday products. The current industrial-scale manufacture of formates requires CO at high pressure and harsh reaction conditions. Herein, we describe a new process for these products without the utilization of hazardous gases and chemicals. By application of ruthenium pincer complexes, a simultaneous methanol dehydrogenation and bicarbonate hydrogenation reaction proceeds, which provides a green synthesis of formate salts with excellent TON (>18 000), TOF (>1300 h-1), and yield (>90 %). Get rid of CO and H 2: An efficient route for the industrial synthesis of formate salts without the utilization of carbon monoxide is highly desirable. A catalytic reaction combining methanol dehydrogenation and bicarbonate hydrogenation has been developed, which provides a green and cost-efficient process for the synthesis of formate salts with excellent turnover numbers and yields.
- Liu, Qiang,Wu, Lipeng,Guelak, Samet,Rockstroh, Nils,Jackstell, Ralf,Beller, Matthias
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- A Raman spectral study of the kinetics of deuterium-hydrogen exchange on the formate anion at elevated temperatures and pressures
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Raman spectra of the hydrogen-deuterium exchange reaction occurring in the HCOO--D2O system at elevated temperatures and pressures are reported. The rate constants at four temperatures have been measured and from these an activation energy of around 170 kJ mol-1 has been calculated. Exchange also takes place in the DCOO--H2O system. The rate constants at four temperatures indicate an activation energy of 93 kJ mol-1.
- Bartholomew, Richard J.,Stevenson, Wendy J.,Irish, Donald E.
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- Revisiting the behaviour of BiVO4 as a carbon dioxide reduction photo-catalyst
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Bismuth vanadate is a widely known photocatalyst for the hydro-reduction of CO2. In spite of the great appeal of such a catalytic system, problems arise due to deactivation of the catalyst with consequent low reaction yield. We have investigated the catalyst behavior during methanol production and have found that the catalyst irreversibly loses vanadium from the structure whilst depositing bismuth oxides on the surface of the catalyst. While catalyst activity can be restored upon heating, leaching of vanadium, leading in long term to catalyst decomposition, is unavoidable and irreversible.
- Sommers, Jacob M.,Alderman, Nicholas P.,Viasus, Camilo J.,Gambarotta, Sandro
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- Carbon dioxide conversion into the reaction intermediate sodium formate for the synthesis of formic acid
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Increased carbon dioxide (CO2) emissions from anthropogenic activities are a contributing factor to the growing global warming worldwide. The economical method to recover and effectively reuse CO2 is through adsorption and absorption. In this study, CO2 is absorbed into the solution of sodium hydroxide having various concentrations (0.01, 0.1, 0.5, 1.0, 3.0 and 5.0?N), and the impact of the solution pH on the various product formation was observed. The resultant products formed at different pH of the absorbing solution are sodium carbonate at pH 10, Trona at pH 9, and sodium hydrogen carbonate at pH 8. The products formed are confirmed through X-ray diffraction analysis. After pH optimization, the sodium hydrogen carbonate formed at pH 8 is converted into sodium formate through hydrogenation in the presence of nickel ferrite catalyst at 80 °C and atmospheric pressure. The sodium formate produced is then used as a precursor to synthesize formic acid upon simple reaction with sulfuric acid. A reaction % age yield of 79 ± 0.2% formic acid is noted. Condensed formic acid vapors are later analyzed, using a high performance?liquid chromatography for the qualitative analysis.
- Masood, Muhammad Hanan,Haleem, Noor,Shakeel, Iqra,Jamal, Yousuf
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- Kinetics and mechanisms of the catalytic reactions of formaldehyde with copper oxides and a copper ion complex in aqueous alkali
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The kinetics of the autocatalytic reactions of formaldehyde with copper(II) and copper(I) oxides and with the Cu2+ ion of the copper EDTA complex, as well as formaldehyde disproportionation in the presence of copper metal, have been investigated in aqueous solutions of sodium hydroxide. Two likely reaction mechanisms are presented. The difference between these mechanisms does not alter the observed kinetics of the processes, whose rate is determined by their first, slow step, namely, the oxidation of the methylene glycol anion adsorbed on the copper surface into formic acid. In the slow step of the first mechanism, a hydride ion is abstracted from the methylene glycol anion and is transferred to copper. In the slow step of the second mechanism, the methylene glycol anion undergoes anodic oxidation, releasing a hydrogen atom and an electron. In the rapid steps of the first mechanism, the hydride ion undergoes anodic oxidation to hydrogen, the copper compound undergoes cathodic reduction to copper metal, and, simultaneously, the electron and hydrogen are transferred to a nonionized formaldehyde molecule to yield methanol. Mathematical models are suggested for the reactions. The effective rate constants and activation energies of the slow steps of the reactions have been determined. The effective rate constants of the noncatalytic reduction reactions of the copper compounds and the ratios of the rates of the rapid hydrogen and methanol formation reactions have been estimated.
- Demchenko,Belkin
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- Homogeneous hydrogenation of saturated bicarbonate slurry to formates using multiphase catalysis
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Formic acid and formate salts are key intermediates along the pathways for CO2utilization and hydrogen storage. Herein we report a highly efficient multiphase catalytic system utilizing a ruthenium PNP pincer catalyst for converting supersaturated bicarbonate solutions and slurries to aqueous formate solutions up to 12 M in molarity. The biphasic catalytic system delivers turnover frequencies up to 73?000 h?1and remains stable for up to 474?000 turnovers once reaction conditions are optimized.
- Filonenko, Georgy A.,Pidko, Evgeny A.,Rebreyend, Christophe
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supporting information
p. 8848 - 8852
(2021/11/23)
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- Preparation method of sodium formate
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The invention discloses a preparation method of sodium formate. The method adopts trifluoroacetoacetic acid ethyl enol sodium salt and formic acid as raw materials, and comprises the following steps: A1, adding formic acid into an ethyl trifluoroacetoacetate enol sodium salt solution, controlling the temperature at 10-60 DEG C, and carrying out heat preservation reaction for 2.0-5.0 hours after the formic acid is added; and A2, carrying out solid-liquid separation on the reaction liquid, wherein the separated solid is crude sodium formate. The method has the advantages of mild reaction, high safety, high sodium formate purity, basically no three wastes and the like.
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Paragraph 0025-0044
(2021/06/26)
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- Artificial co-enzyme based on carbamoyl-modified viologen derivative cation radical for formate dehydrogenase in the catalytic CO2reduction to formate
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Formate dehydrogenase (CbFDH) from Candida boidinii is a useful biocatalyst for CO2 reduction to formate in the photoredox system, and consists of a visible-light sensitizer and an electron mediator. The electron mediator, single-electron reduced 4,4′-bipyridinium salts (4,4′-BPs) represented by methylviologen act as the co-enzyme for CbFDH in the CO2 reduction to formate. Considering that the single-electron reduced 4,4′- or 2,2′-BPs activate the CbFDH-mediated CO2 reduction to formate, the architecture of the effective co-enzyme based on the chemical modification of BP is useful for the development of the catalytic reduction of CO2 to formate with CbFDH. NAD+ has a carbamoyl group or nicotinamide moiety, which can form hydrogen bonds with some amino residues in CbFDH. Thus, we predicted that the affinity of 4,4′-BP for CbFDH could be improved by introducing a carbamoyl group or nicotinamide moiety into 4,4′-BP. In this work, the interaction between the single-electron reduced 1-carbamoylmethyl-1′-methyl-4,4′-bipyridinium salt, 1,1′-dicarbamoylmethyl-4,4′-bipyridinium salt and 1-nicotinamidethyl-1′-methyl-4,4′-bipyridinium salt and CbFDH in the CO2 reduction to formate is elucidated by enzymatic kinetic analysis, the docking simulation and density functional theory calculation.
- Miyaji, Akimitsu,Amao, Yutaka
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p. 18808 - 18812
(2020/11/18)
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- CATALYTIC CONVERSION OF CARBON DIOXIDE TO METHANOL
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The present disclosure relates to a new catalytic process for the production of methanol from carbon dioxide, comprising: (1) the conversion of carbon dioxide and hydrogen to formic acid or formate salts; (2) converting the formic acid or formate salts to diformate esters of diols; (3) hydrogenating the diformate esters to methanol and diols. The diols produced from the hydrogenation reaction can be recovered and re-used to prepare the diformate esters.
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Page/Page column 26; 27
(2019/10/29)
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- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
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Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)CNtBu, Ph2CCH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
-
supporting information
(2019/04/17)
-
- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
-
Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)C=NtBu, Ph2C=CH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
-
supporting information
p. 6082 - 6091
(2019/04/17)
-
- Transforming atmospheric CO2 into alternative fuels: A metal-free approach under ambient conditions
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This work demonstrates the first-ever completely metal-free approach to the capture of CO2 from air followed by reduction to methoxyborane (which produces methanol on hydrolysis) or sodium formate (which produces formic acid on hydrolysis) under ambient conditions. This was accomplished using an abnormal N-heterocyclic carbene (aNHC)-borane adduct. The intermediate involved in CO2 capture (aNHC-H, HCOO, B(OH)3) was structurally characterized by single-crystal X-ray diffraction. Interestingly, the captured CO2 can be released by heating the intermediate, or by passing this compound through an ion-exchange resin. The capture of CO2 from air can even proceed in the solid state via the formation of a bicarbonate complex (aNHC-H, HCO3, B(OH)3), which was also structurally characterized. A detailed mechanism for this process is proposed based on tandem density functional theory calculations and experiments.
- Chandra Sau, Samaresh,Bhattacharjee, Rameswar,Hota, Pradip Kumar,Vardhanapu, Pavan K.,Vijaykumar, Gonela,Govindarajan,Datta, Ayan,Mandal, Swadhin K.
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p. 1879 - 1884
(2019/02/12)
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- CATALYST FOR DEHYDROGENATION REACTION OF FORMATE AND HYDROGENATION REACTION OF BICARBONATE AND PREPARATION METHOD THEREOF
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Provided is a method for preparing a catalyst for a dehydrogenation reaction of formate and a hydrogenation reaction of bicarbonate, the method including: adding a silica colloid to a polymerization step of polymerizing aniline and reacting the resulting mixture to form a poly(silica-aniline) composite; carbonizing the corresponding poly(silica-aniline) composite under an atmosphere of an inert gas; removing silica particles from the corresponding poly(silica-aniline) composite to form a polyaniline-based porous carbon support; and fixing palladium particles on the corresponding polyaniline-based porous carbon support to prepare the catalyst.
- -
-
Page/Page column 6
(2018/04/20)
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- Manganese-Catalyzed Dual-Deoxygenative Coupling of Primary Alcohols with 2-Arylethanols
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Reported herein is a general and efficient dual-deoxygenative coupling of primary alcohols with 2-arylethanols catalyzed by a well-defined Mn/PNP pincer complex. This reaction is the first example of the catalytic dual-deoxygenation of alcohols using a non-noble-metal catalyst. Both deoxygenative homocoupling of 2-arylethanols (17 examples) and their deoxygenative cross-coupling with other primary alcohols (20 examples) proceeded smoothly to form the corresponding alkenes by a dehydrogenation and deformylation reaction sequence.
- Wang, Yujie,Shao, Zhihui,Zhang, Kun,Liu, Qiang
-
supporting information
p. 15143 - 15147
(2018/11/01)
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- Synthesis of 2-Aminopyridines via a Base-Promoted Cascade Reaction of N-Propargylic β-Enaminones with Formamides
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N-Substituted formamides as nucleophiles react with in situ-generated 1,4-oxazepines from N-propargylic β-enaminones followed by spontaneous N-deformylation to deliver densely substituted 2-aminopyridines in good yields (31-88%). The formyl group is found to be a superior traceless activating group of free amines and would ultimately be removed in situ. This reaction proceeds smoothly at room temperature, in the presence of NaOH as sole additive, without protection from the atmosphere and generates H2O and sodium formate as byproducts.
- Weng, Yunxiang,Kuai, Changsheng,Lv, Weiwei,Cheng, Guolin
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p. 5002 - 5008
(2018/05/17)
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- HYDROGEN PRODUCTION FROM ETHYLENE GLYCOL UNDER BASIC CONDITIONS
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Disclosed is a method of producing hydrogen from monoethylene glycol. The method includes mixing an aqueous base, monoethylene glycol, and an iridium chloride (IrCl3) catalyst solubilized therein under conditions sufficient to produce hydrogen from the ethylene glycol present in the basic homogeneous aqueous solution.
- -
-
Paragraph 0036
(2018/09/28)
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- PROCESS FOR PREPARING METHANOL FROM CARBON DIOXIDE
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The present invention relates to the field of chemical sciences. The present invention generally relates to a simple, economic and effective process for the conversion of carbon dioxide to methanol in the presence of carbenes or their derivatives/adducts, under mild reaction conditions. Further, said method does not require use of toxic metals/compounds for carrying out the conversion of carbon dioxide to methanol, unlike methods of the prior art.
- -
-
Page/Page column 27; 28
(2018/05/24)
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- Method for synthesizing sodium formate by using coke gas making
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The invention discloses a method for synthesizing sodium formate by using coke gas making. The method comprises the following steps: blowing air from the bottom of a coal gas generation furnace; after generated gas is washed in a water washing tower, conveying the gas from the tower top into an alkaline washing tower through a water ring vacuum pump, enabling the gas to be in full contact with caustic soda back flow from an alkaline seal, and enabling carbon monoxide to enter a water cooling tower from the tower top; enabling the gas to enter a gas-liquid separator, putting the gas subjected to water removal into a coal gas compressor for pressurization, then putting the gas subjected to oil-water separation into a sleeve heat exchanger, conveying alkaline liquid into a sleeve from a caustic soda storage tank through a metering pump, enabling the alkaline liquid to be fully mixed with coal gas, and heating with steam in a jacket; putting a heated mixture into a reaction pipe for full reaction at certain pressure and temperature, and enabling the reacted gas carrying finished sodium formate to pass through a cyclone hydraulic separator, wherein the gas is emptied, and liquid flows into a sodium formate storage tank under the gravity. According to the method disclosed by the invention, the product quality and the purity of the sodium formate are improved, and the environment friendliness of the production process is guaranteed.
- -
-
Paragraph 0015
(2017/07/06)
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- A nanoporous nickel catalyst for selective hydrogenation of carbonates into formic acid in water
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An efficient unsupported nanoporous nickel (NiNPore) material for the hydrogenation of carbonates to formic acid (FA) in water was investigated for the first time. NiNPore is an environmentally benign catalyst and it exhibited remarkable catalytic activity in the reduction of a wide range of carbonates to afford formic acid in excellent yields with high selectivity, and maximum values of 86.6% from NaHCO3 and even up to 92.1% from KHCO3 were obtained. The hydrogen pressure and pKa of the carbonates had a significant influence on the formation of FA. The catalyst was easily recovered and could be recycled at least five times without leaching and loss of activity. The present study demonstrated a potential application for the synthesis of FA from CO2 or carbonate compounds.
- Wang, Tian,Ren, Dezhang,Huo, Zhibao,Song, Zhiyuan,Jin, Fangming,Chen, Mingwei,Chen, Luyang
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supporting information
p. 716 - 721
(2017/08/17)
-
- Efficient and Bio-inspired Conversion of Cellulose to Formic Acid Catalyzed by Metalloporphyrins in Alkaline Solution
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A bio-inspired approach for efficient conversion of cellulose to formic acid (FA) was developed in an aqueous alkaline medium. Metalloporphyrins mimicking cytochrome P450 exhibit efficiently and selectively catalytic performance in catalytic conversion of cellulose. High yield of FA about 63.7% was obtained by using sulfonated iron(III) porphyrin as the catalyst and O2 as the oxidant. Iron(III)-peroxo species, TSPPFeIIIOO?, was involved to cleave the C-C bonds of gluconic acid to FA in this catalytic system. This approach used relatively high concentration of cellulose and ppm concentration of catalyst. This work may provide a bio-inspired route to efficient conversion of cellulose to FA.
- Liu, Qiang,Zhou, Doudou,Li, Zongxiang,Luo, Weiping,Guo, Cancheng
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p. 1063 - 1068
(2017/07/24)
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- METAL CATALYZED PROCESS FOR REDUCTION OF CO2 TO SODIUM FORMATE AND FORMIC ACID
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The patent discloses a one step, one pot metal catalyzed process for synthesis of formic acid or sodium formate from CO2 in the presence of reducing agent and a catalyst or without catalyst at moderate temperature and atmospheric pressure with high yields.
- -
-
Paragraph 073; 074
(2016/02/29)
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- Method for preparing formate through carbon dioxide catalytic hydrogenation
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The invention belongs to the technical field of carbon dioxide resource utilization and relevant chemistry, and relates to a method for preparing formate through carbon dioxide catalytic hydrogenation. The method is characterized by comprising the steps that carbon dioxide is used as a raw material and reacts with hydrogen under the catalysis of nano-porous palladium catalyst and the alkaline condition to obtain formate. By means of the method for preparing the formate through carbon dioxide catalytic hydrogenation, the preparation route is short, raw materials are cheap and easy to obtain, conditions are mild, operation is simple and convenient, and the reaction yield is high.
- -
-
Paragraph 0020; 0021; 0022; 0023
(2016/10/09)
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- A palladium catalyzed carbon monoxide under method of making sodium formate
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The invention provides a synthetic method of sodium formate. The method comprises using carbon monoxide and sodium hydroxide aqueous solutions, reacting, separating and drying to obtain the sodium formate under the existence of catalyst palladium dichloride, ligand triphenylphosphine and an organic solvent. The method can be achieved under conditions that reaction temperature ranges from 30 DEG C to 90 DEG C and the pressure ranges from 0.05MPa to 0.7MPa, is soft in reaction condition, and greatly improves a traditional synthetic method of the sodium formate.
- -
-
Paragraph 0008; 0009
(2017/02/17)
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- METHODS AND CATALYST SYSTEMS FOR CARBON DIOXIDE CONVERSION
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Disclosed herein are embodiments of a heterogeneous catalyst system and methods of using the same to convert CO2-derived compounds to formate, formic acid, or a mixture thereof. The disclosed heterogeneous catalyst systems exhibit superior reactivity and stability in comparison to homogeneous catalyst systems and also can convert a variety of CO2-derived compounds to formate, formic acid, or mixtures thereof, in high yields using economical and environmentally friendly reaction conditions.
- -
-
Paragraph 0105; 0119
(2016/06/06)
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- Highly efficient hydrogen storage system based on ammonium bicarbonate/formate redox equilibrium over palladium nanocatalysts
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Abstract A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density. Revolution of H2 evolution? A highly efficient hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over a carbon-supported palladium nanocatalyst. Ammonium ion improves the efficiencies of both the hydrogenation of bicarbonate and the dehydrogenation of formate. By adjusting the reaction temperature and pressure, the extent of chemical reaction of hydrogen storage and evolution can be well controlled within the same catalytic system.
- Su, Ji,Yang, Lisha,Lu, Mi,Lin, Hongfei
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p. 813 - 816
(2015/06/02)
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- Exploring the reactivity of nickel pincer complexes in the decomposition of formic acid to CO2/H2 and the hydrogenation of NaHCO3 to HCOONa
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The nickel-catalyzed decomposition of formic acid to yield molecular hydrogen and the nickel-catalyzed hydrogenation of bicarbonate as a carbon dioxide mimic have been examined. Well-defined nickel complexes modified by a PCP-pincer ligand, especially nickel hydride and nickel formate complexes, revealed catalytic activity with turnover numbers of up to 626 (decomposition) and 3000 (hydrogenation). Thus, a formal hydrogen storage and release cycle performed by a well-defined nickel catalyst was accomplished.
- Enthaler, Stephan,Brück, Andreas,Kammer, Anja,Junge, Henrik,Irran, Elisabeth,Gülak, Samet
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- Highly active phosphine-free bifunctional iron complex for hydrogenation of bicarbonate and reductive amination
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Based on a "transition metal frustrated Lewis pair" approach, a cyclopentadienone iron tricarbonyl complex has been designed and applied in the reductive amination and hydrogenation of bicarbonate. This well-defined phosphine-free complex displays the best activities reported to date for an iron complex in the reduction of bicarbonate into formate and in reductive amination.
- Thai, Trieu-Tien,Mérel, Delphine S.,Poater, Albert,Gaillard, Sylvain,Renaud, Jean-Luc
-
supporting information
p. 7066 - 7070
(2015/05/05)
-
- A Viable Hydrogen Storage and Release System Based on Cesium Formate and Bicarbonate Salts: Mechanistic Insights into the Hydrogen Release Step
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Aqueous solutions of cesium formate and bicarbonate represent an effective hydrogen storage-delivery couple that undergoes either release or take up of hydrogen in the presence of {RuCl2(mTPPTS)2}2 (TPPTS=triphenylphosphine trisulfonate) and excess mTPPTS ligand, with no other additives required. Cesium salt solutions offer the advantage of improved volumetric and gravimetric H2 density compared to their sodium and potassium analogs, owing to their high water solubility. Details of the equilibrium between formate and bicarbonate, which constitutes an important parameter for the applicability of this H2 storage/release cycle, were determined. H2 production is readily tunable by controlling the operating pressure. This behavior was also rationalized through the identification of catalytic intermediates under various conditions. High concentration formate and bicarbonate solutions were used during the tests and the bidirectional catalytic system could be recycled without loss of activity or replacement of solvent. A tentative mechanism is proposed for the formate dehydrogenation step. Among the identified hydride species, the pentacoordinated [RuH(H2O)(TPPTS)3] complex was indispensable for promoting the formate dehydrogenation reaction. Cesium cycling: In the presence of a ruthenium catalytic precursor and a stabilizing phosphine ligand, cesium formate and bicarbonate in aqueous solution perform as a stable hydrogen storage-release couple. An intermediate pentacoordinated 16-electron ruthenium hydride complex is crucial in the promotion of the formate dehydrogenation.
- Sordakis, Katerina,Dalebrook, Andrew F.,Laurenczy, Gbor
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p. 2332 - 2339
(2015/08/11)
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- Photoredox-Catalyzed Intramolecular Aminodifluoromethylation of Unactivated Alkenes
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A photoredox catalyzed aminodifluoromethylation of unactivated alkenes has been developed in which HCF2SO2Cl is used as the HCF2 radical source. Sulfonamides were active nucleophiles in the final step of a tandem addition/oxidation/cyclization process to form pyrrolidines, and esters were found to cyclize to form lactones. Thus, a variety of pyrrolidines and lactones were obtained in moderate to excellent yield. In order for the cyclization reactions to be efficient, a combination of a copper catalyst (Cu(dap)2Cl) and silver carbonate was crucial to suppressing a competing chloro, difluoroalkylation process.
- Zhang, Zuxiao,Tang, Xiaojun,Thomoson, Charles S.,Dolbier, William R.
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supporting information
p. 3528 - 3531
(2015/07/28)
-
- Reversible interconversion of CO2 and formate by a molybdenum-containing formate dehydrogenase
-
CO2 and formate are rapidly, selectively, and efficiently interconverted by tungsten-containing formate dehydrogenases that surpass current synthetic catalysts. However, their mechanism of catalysis is unknown, and no tractable system is available for study. Here, we describe the catalytic properties of the molybdenum-containing formate dehydrogenase H from the model organism Escherichia coli (EcFDH-H). We use protein film voltammetry to demonstrate that EcFDH-H is a highly active, reversible electrocatalyst. In each voltammogram a single point of zero net current denotes the CO2 reduction potential that varies with pH according to the Nernst equation. By quantifying formate production we show that electrocatalytic CO2 reduction is specific. Our results reveal the capabilities of a Mo-containing catalyst for reversible CO2 reduction and establish EcFDH-H as an attractive model system for mechanistic investigations and a template for the development of synthetic catalysts.
- Bassegoda, Arnau,Madden, Christopher,Wakerley, David W.,Reisner, Erwin,Hirst, Judy
-
supporting information
p. 15473 - 15476
(2015/01/09)
-
- An aqueous rechargeable formate-based hydrogen battery driven by heterogeneous Pd catalysis
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The formate-based rechargeable hydrogen battery (RHB) promises high reversible capacity to meet the need for safe, reliable, and sustainable H2 storage used in fuel cell applications. Described herein is an additive-free RHB which is based on repetitive cycles operated between aqueous formate dehydrogenation (discharging) and bicarbonate hydrogenation (charging). Key to this truly efficient and durable H2 handling system is the use of highly strained Pd nanoparticles anchored on graphite oxide nanosheets as a robust and efficient solid catalyst, which can facilitate both the discharging and charging processes in a reversible and highly facile manner. Up to six repeated discharging/charging cycles can be performed without noticeable degradation in the storage capacity.
- Bi, Qing-Yuan,Lin, Jian-Dong,Liu, Yong-Mei,Du, Xian-Long,Wang, Jian-Qiang,He, He-Yong,Cao, Yong
-
supporting information
p. 13583 - 13587
(2015/02/19)
-
- Alcoholysis of fluoroform
-
Fluoroform (CHF3) reacts with alkali metal alkoxides MOR (M = Na, K) in the corresponding alcohols ROH (R = Me, Et, i-Pr, t-Bu, and Allyl) at 80-120°C to give orthoformate esters HC(OR)3 in 55-90% yield. Particularly notable is the f
- Miloserdov, Fedor M.,Grushin, Vladimir V.
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p. 105 - 109
(2015/03/03)
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- The selective oxidation of 1,2-propanediol to lactic acid using mild conditions and gold-based nanoparticulate catalysts
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The use of bio-renewable resources for the generation of materials and chemicals continues to attract significant research attention. It is well established that glycerol is an excellent starting material for the production of 1,2-propanediol by dehydration/hydrogenation and that this can subsequently be oxidised to lactic acid, which has the potential to be used as a major chemical in the production of biodegradable polymers. Previous studies using gold catalysts for the oxidation of 1,2-propanediol have used elevated temperatures and pressures. We now show that the oxidation of 1,2-propanediol to form lactic acid can be carried out selectively under mild reaction conditions with gold-platinum catalysts prepared using a sol-immobilisation method, with activated carbon as the support. Carrying out the reaction at ambient temperature with air significantly improves the reaction in terms of its environmental impact and its industrial attractiveness, as lactic acid can be obtained with high selectivity.
- Ryabenkova, Yulia,He, Qian,Miedziak, Peter J.,Dummer, Nicholas F.,Taylor, Stuart H.,Carley, Albert F.,Morgan, David J.,Dimitratos, Nikolaos,Willock, David J.,Bethell, Donald,Knight, David W.,Chadwick, David,Kiely, Christopher J.,Hutchings, Graham J.
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p. 139 - 145
(2013/08/24)
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- Synthesis of stable phosphomide ligands and their use in Ru-catalyzed hydrogenations of bicarbonate and related substrates
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New benzoyl- and naphthoyl-substituted phosphines have been synthesized, which are stable to air and moisture. Testing these so-called phosphomide ligands in the presence of different ruthenium precursors, the hydrogenation of sodium bicarbonate (NaHCO3) to sodium formate (NaHCO2) proceeded with good catalyst turnover numbers in the range of 1300-1600 at 80 °C and a total pressure of hydrogen of 60 bar in the absence of amines or other additives. Similarly, catalytic hydrogenations of carbon dioxide, cinnam-, and benzaldehyde were possible with these new ruthenium complexes. As an intermediate of the catalytic cycle the defined ruthenium complex [(η6-C6H6)-RuCl2(Cy 2P(1-naphthoyl)] (Cy=cyclohexyl) was prepared and characterized by X-ray crystallography. Ruthenium and phosphor work wonders: Air-stable ruthenium phosphomide complexes are active catalysts in the hydrogenation of sodium bicarbonate, carbon dioxide, and carbonyl compounds. Hydrogenation proceeds with high catalyst turnover numbers in the absence of amines or other additives. The application range of these new ruthenium catalysts also includes the hydrogenation of cinnamaldehyde and benzaldehyde. Copyright
- Gowrisankar, Saravanan,Federsel, Christopher,Neumann, Helfried,Ziebart, Carolin,Jackstell, Ralf,Spannenberg, Anke,Beller, Matthias
-
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- Hydride-bridged NiRh complexes with tunable N3S2 dithiolato ligands and their utilization as catalysts for hydrogenation of aldehydes and CO2 in aqueous media
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New N3S2 dithiolato ligands, 1,4-bis(2-mercaptoethyl) -7-R-1,4,7-triazacyclononane (RTACN-S2H2; R = Ts, iPr) were synthesized and reacted with NiII ion to give mononuclear complexes [Ni(RTACN-S2)] (R = Ts (1a), iPr (1b)). Complexes 1a and 1b were further transformed by treatment with Rh III species into a series of NiIIRhIII heterodimetallic compounds, [Ni(RTACN-S2)RhCp*X]X′ (R = Ts, X = Cl, X′ = Cl, OTf ([2a]X′); R = Ts, X = X′ = NO 3 ([3a]NO3); R = iPr, X = Cl, X′ = Cl, NO3, PF6 ([2b]X′)). Complexes [3a]NO3 and [2b]NO3 were readily reacted with H2 (0.1 MPa) in water at room temperature to afford hydride-bridged NiIIRhIII dinuclear complexes, [(RTACN-S2)Ni(μ-H)RhCp*]NO3 (R = Ts ([4a]NO3), iPr ([4b]NO3)), which were successfully characterized by X-ray crystallography. Upon the heterolytic activation of H2, the Ni-Rh interatomic distances were dramatically decreased from 3.2130(6)-3.262(2) A ([2a]OTf, [2b]NO3, [3a]NO3) to 2.6921(6)-2.7228(4) A ([4a]NO3, [4b]NO3), resulting in semibridging Ni(μ-H)Rh cores. In addition, the stability of the hydride of [4a]+ and [4b]+ were interestingly tuned by varying the R group of the TACN ligand through trans influence at the NiII center (Ni-NR = 2.188(3) A ([4a] +), 2.056(2) A ([4b]+). In fact, [4a]+ was quite stable and capable of reducing benzaldehyde in water, although [4b]+ quickly decomposed under similar conditions. Catalytic hydrogenation of aldehydes and CO2 in water has been established by using [3a]NO3 and [2a]Cl as precursors of an active species, [4a]+, and found to be interestingly contrasted to the inactive precursor [2b]NO3 with R = iPr. These results indicated that the properties and reactivity of the Ni(μ-H)Rh complexes can be controlled by changing the substituents of the N3S2 supporting ligands.
- Kure, Bunsho,Taniguchi, Ayami,Nakajima, Takayuki,Tanase, Tomoaki
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experimental part
p. 4791 - 4800
(2012/10/08)
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- Well-defined iron catalyst for improved hydrogenation of carbon dioxide and bicarbonate
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The most efficient, stable, and easy-to-synthesize non-noble metal catalyst system for the reduction of CO2 and bicarbonates is presented. In the presence of the iron(II)-fluoro-tris(2-(diphenylphosphino)phenyl)phosphino] tetrafluoroborate complex 3, the hydrogenation of bicarbonates proceeds in good yields with high catalyst productivity and activity (TON > 7500, TOF > 750). High-pressure NMR studies of the hydrogenation of carbon dioxide demonstrate that the corresponding iron-hydridodihydrogen complex 4 is crucial in the catalytic cycle.
- Ziebart, Carolin,Federsel, Christopher,Anbarasan, Pazhamalai,Jackstell, Ralf,Baumann, Wolfgang,Spannenberg, Anke,Beller, Matthias
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supporting information
p. 20701 - 20704
(2013/02/22)
-
- Kinetics of the oxidation of lactose by copper(II) complexed with bipyridyl in alkaline medium using chloro-complex of rhodium(III) in its nano-concentration range as homogeneous catalyst: A spectrophotometric study
-
Kinetics of the oxidation of lactose by Cu(II) complexed with bipyridyl have been investigated at 40 °C for the first time spectrophotometrically using Rh(III) chloride as homogeneous catalyst in aqueous alkaline medium in its nano-concentration range. The order of reaction was found to be fractional positive-order, when the concentration of Rh(III) chloride was varied from 0.30 × 10-9 M to 6.00 × 10-9 M. The reaction shows fractional positive-order kinetics with respect to [lactose] and [OH -] and zeroth-order kinetics with respect to [Cu(II)]. The reaction also shows slight increase in the rate by decreasing dielectric constant of the medium and remains unaffected by the change in ionic strength of the medium. The reaction was carried out at four different temperatures and observed values of rate constants were utilized to calculate various activation parameters specially the entropy of activation (ΔS#). The species, [RhCl3(H2O)2OH]-, was postulated as the main reactive species of Rh(III) chloride for the oxidation of lactose by Cu(II) in alkaline medium. On the basis of kinetic and equivalence studies together with spectrophotometric information for the formation of a complex, the most appropriate mechanism for the aforesaid reaction has been proposed. Support to the proposed mechanism was also given by the observed activation parameters and multiple regression analysis. Sodium salts of formic acid, arabinonic acid and lyxonic acid were identified as the main oxidation products of the reaction under investigation.
- Kumar Singh, Ashok,Singh, Manjula,Srivastava, Jaya,Rahmani, Shahla
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scheme or table
p. 94 - 101
(2012/08/08)
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