- Catalytic hydrogenation of CO2from airviaporous silica-supported Au nanoparticles in aqueous solution
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The conversion of the ubiquitous greenhouse gas CO2to valuable organic products is much sought after. Herein, the hydrogenation of CO2to C1 products with an 80% yield in water is reported using a novel catalyst, porous-silica-supported Au nanoparticles (Au/SiO2). In the presence of a Lewis acid, boric acid, the Au/SiO2catalyst enables an efficient conversion of amine-captured CO2to methanol, formate, and formamide. A mechanistic study involving isotopic labelling suggests that methanol production in the catalytic process arises from the direct hydrogenation of formate. Most importantly, this one-pot, two-step process is able to convert CO2in air at ambient pressures to C1 products in the absence of an organic solvent. Furthermore, the catalyst is readily recycled without further purification or reactivation and shows no significant decrease in catalytic activity after four reaction cycles in a reusability test.
- Lennox, R. Bruce,Li, Chao-Jun,Ni, Siting,Roy, Ranjan,Zhu, Jun
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p. 3740 - 3749
(2021/06/06)
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- Zn-catalyzed cyanation of aryl iodides
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We report the first example of zinc-catalyzed cyanation of aryl iodides with formamide as the cyanogen source. The transformation was promoted by the bisphosphine Nixantphos ligand. Under optimized conditions, a variety of electron-donating and electron-withdrawing aryl iodides were converted into nitrile products in good to excellent yields. This approach is an exceedingly simple and benign method for the synthesis of aryl nitriles and is likely to proceed via a dinuclear Zn-concerted catalysis.
- Zhao, Lulu,Dong, Yanan,Xia, Qiangqiang,Bai, Jianfei,Li, Yuehui
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supporting information
p. 6471 - 6477
(2020/06/08)
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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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p. 121 - 128
(2020/01/03)
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- Hydrogenation of Carbon Dioxide with Organic Base by PCIIP-Ir Catalysts
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Novel PCIIP-IrI monochloride complexes (1-Cl and 2-Cl) bearing a phosphine-carbene-phosphine pincer type ligand were synthesized. Reactions of 1-Cl with hexachloroethane, hydrogen chloride, and lithium triethylborohydride under a dihydrogen atmosphere afforded PCIIP-IrIII trichloride (1-Cl3), hydride dichloride (1-HCl2), and trihydride (1-H3) complexes, respectively. The strong electron-donating ability of carbene in PCIIP-Ir complexes was confirmed by X-ray crystallography and DFT calculations. Moreover, in complex 1-Cl, strong π back-donation from the iridium center to the carbene carbon was observed. Hydrogenation of CO2 with triethanolamine catalyzed by PCIIP-Ir complexes was investigated. The novel PCIIP-Ir complex 1-Cl exhibited a longer lifetime in comparison to the PNP-IrIII complex 3-H3: the turnover number of 1-Cl is significantly higher than that of 3-H3 (in 46 h, 1-Cl 230000 and 3-H3 54000).
- Takaoka, Satoko,Eizawa, Aya,Kusumoto, Shuhei,Nakajima, Kazunari,Nishibayashi, Yoshiaki,Nozaki, Kyoko
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p. 3001 - 3009
(2018/10/02)
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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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p. 716 - 721
(2017/08/17)
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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.
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Paragraph 0164
(2016/06/06)
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- Selected paper development of highly active IrPNP catalysts for hydrogenation of carbon dioxide with organic bases
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Methoxy-substituted PNP-iridium(III) complexes and pyrazine-based PNP-iridium(III) complexes were developed and used to hydrogenate carbon dioxide in the presence of triethanolamine as a base. The methoxy-substituted PNP-hydridodichloridoiridium complex (C-HCl2) showed the highest turnover number, 160000; this is the highest value ever reported with an organic base in an aqueous medium. The reactivities of these complexes, derived from their ligand modification, were further studied. The results were as follows. (i) The pyrazine-based PNP-trihydridoiridium complex undergoes release of dihydrogen to afford dihydridoamido complex, possibly because of easy dearomatization of the pyrazine ring. This process was reversible, i.e., B-H2amido can readily be converted back to B-H3 on exposure to dihydrogen. (ii) The p-methoxy-substituted dihydridochlorido complex showed facile disproportionation of the chloride anion on the iridium center; this is attributed to the electron-donating nature of the methoxypyridine backbone.
- Aoki, Wataru,Wattanavinin, Natdanai,Kusumoto, Shuhei,Nozaki, Kyoko
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supporting information
p. 113 - 124
(2016/01/27)
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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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- High yield production of formate by hydrogenating CO2 derived ammonium carbamate/carbonate at room temperature
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A sustainable economy is needed to recycle carbon rather than to irreversibly use stored carbon in fossil fuels. Instead of releasing CO2 into the atmosphere, its value can be recognized as a base C1 material for chemicals. In this study, a new CO2 utilization strategy is developed via the hydrogenation of CO2 derived ammonium carbamates/carbonates, which are the intermediates in industrial urea production or carbon capture processes, to produce value-added formate chemicals. A high yield of formate, ~92%, was achieved after hydrogenating ammonium carbamates in the ethanol-water solution at room temperature with the carbon supported palladium nano-catalyst. The ethyl carbonate ions in the ammonium carbamate/carbonate solutions were speciated by 13C NMR and were attributed to the superior hydrogenation efficiency. Ammonium ions promote the formation of ethyl carbonate ions in the presence of ethanol. The solvent affects the distribution of the reactive intermediates.
- Su, Ji,Lu, Mi,Lin, Hongfei
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supporting information
p. 2769 - 2773
(2015/05/27)
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- 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
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supporting information
p. 13583 - 13587
(2015/02/19)
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- PRODUCTION OF FORMAMIDES
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A process is proposed for production of formamides by reaction of carbon dioxide with hydrogen in a hydrogenation reactor I in the presence of a catalyst comprising an element from group 8, 9 or 10 of the periodic table,a tertiary amine comprising at least 6 carbon atoms per molecule, and alsoa polar solvent, to form formic acid-amine adducts as intermediates, which are subsequently reacted with ammonia or amines in a reactor to obtain a two-phase liquid reaction effluent from which the liquid phase enriched with the formamides is distillatively separated to recover the formamide.
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Page/Page column 10; 12
(2012/04/04)
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- Oxidative degradation of reducing carbohydrates to ammonium formate with H2O2 and NH4OH
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Oxidation of various carbohydrates into ammonium formate was investigated in the presence of hydrogen peroxide and ammonium hydroxide. Most of the examined carbohydrates except nonreducing sugars were efficiently converted into ammonium formate under envi
- Pullanikat, Prasanna,Jung, Sangmook J.,Yoo, Kyung Soo,Jung, Kyung Woon
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supporting information; experimental part
p. 6192 - 6194
(2011/01/04)
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- PROCESS FOR PREPARING CONCENTRATED SOLUTIONS OF SALTS OF ORGANIC ACIDS
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The present invention generally relates to the partial chemical neutralization of organic acids to make compositions used in animal nutrition. More particularly, the present invention relates to the use of a cooled reactor to prepare aqueous compositions of partially neutralized organic acids by a continuous or semi-continuous method of reacting an alkali with an organic acid dispersed or dissolved in an aqueous system. The alkali source is present in an amount less than the stiochometric amount required for complete neutralization of the organic acid.
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Page/Page column 5
(2009/04/24)
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