Carbon dioxide to formic acid

The same authors proposed a complex system for the electrochemically driven enzymatic reduction of carbon dioxide to form methanol. In this case, methyl viologen or the cofactor PQQ were used as mediators for the electroenzymatic reduction of carbon dioxide to formic acid catalyzed by formate dehydrogenase followed by the electrochemically driven enzymatic reduction of formate to methanol catalyzed by a PQQ-dependent alcohol dehydrogenase. With methyl viologen as mediator, the reaction goes through the intermediate formation of formaldehyde while with PQQ, methanol is formed directly [77],... 

P. G. Jessop, Y. Hsiao, T. Ikariya, R. Noyori, Homogeneous Catalysis in Supercritical Fluids Hydrogenation of Supercritical Carbon Dioxide to Formic Acid, Alkyl Formates, and Formamides ,J. Am Chem Soc 1996,118, 344-355. 

A nice example of a homogeneous catalytic hydrogenation is the reduction of carbon dioxide to formic acid, carried out in SC-CO2 in the presence of a soluble ruthenium(II)-trimethylphosphane catalyst and triethylamine at 50 °C and 21 MPa... 

Tlte catalytic fixation of carbon dioxide to formic acid is possible, using a combination of Group Vlil transition metal complexes and bases in the presence of water. Typical catalysts are Pdfdppe) and RuH (PPh3)4, but nickel, rhodium. 

Jessop, P.G. Hsiao, Y. Ikariya, T. Noyori, R. Homogeneous catalysis in supercritical fluids hydrogenation of supercritical carbon dioxide to formic acid, alkyl formates, and formamides. J. Am. Chem. Soc. 1996, 118 (2), 344-55. 

Reduction of carbon dioxide to formic acid (and its derivatives) is a very active field of research that has been amply reviewed.18-20,37,3 8 While some of the results are close to commercialization, others can be regarded as promising developments. It should also be realized that presently H2 is generated on a fossil fuel basis (natural gas, coal) accompanied by the formation of C02. Therefore, the hydrogenation of carbon dioxide will not ease the C02 burden however, it can be very useful for synthetic purposes. 

Jessop and co-workers have pointed out that homogeneous catalysis in supercritical fluids can offer high rates, improved selectivity, and elimination of mass-transfer problems.169 They have used a ruthenium phosphine catalyst to reduce supercritical carbon dioxide to formic acid using hydrogen.170 The reaction might be used to recycle waste carbon dioxide from combustion. It also avoids the use of poisonous carbon monoxide to make formic acid and its derivatives. There is no need for the usual solvent for such a reaction, because the excess carbon dioxide is the solvent. If the reaction is run in the presence of dimethy-lamine, dimethylformamide is obtained with 100% selectivity at 92-94% conversion.171 In this example, the ruthenium phosphine catalyst was supported on silica. Asymmetric catalytic hydrogenation of dehydroaminoacid derivatives (8.16) can be performed in carbon dioxide using ruthenium chiral phosphine catalysts.172... 

Value added products, such as the reduction of oxalic acid to glyoxylic acid, are nowadays developed at an industrial scale (BASF—Badische Anilin und Soda-Fabriken). This process uses non-precious metals such as lead. This electrode material reduces carbon dioxide to formic acid in an aqueous medium and to oxalic acid in an organic solvent. This approach can be used to develop environmentally friendly value added products from abundant anthropogenic carbon dioxide. 

Kuen has shown that gases from Fenton reagent-carbohydrate systems consist almost entirely of carbon dioxide. This fact has been exploited for simple, manometric studies of the iron (III) chloride-D-glucono-1,5-lactone-hydrogen peroxide reaction. Equivalent dismutation between carbohydrate fragments, or reduction of carbon dioxide to formic acid, have been suggested in order to account for the deficit (about 66%) in carbon dioxide arising from the oxidative scission. ... 

Hydrogenation of carbon dioxide to formic acid and decomposition of formic acid to dihydrogen and carbon dioxide... 

HYDROGENATION OF CARBON DIOXIDE TO FORMIC ACID AND DECOMPOSITION OF FORMIC ACID TO DIHYDROGEN AND CARBON DIOXIDE... 

Also, I wish to mention the catalytic reaction which proceeds via metathesis with heterolytic o-bond activation. Hydrogenation of carbon dioxide to formic acid is one of attractive transition-metal catalyzed CO2 fixation reactions. Rh(I), Rh(III), and Ru(II) complexes were used as a catalyst [54-56]. Of those catalysts, the Ru(II)-catalyzed hydrogenation of CO2 has drawn considerable interest because of its very high efficiency. Its catalytic cycle was theoretically investigated [57]. In this catalytic reaction, the first step is the insertion of CO2 into the Ru-H bond, to afford the ruthenium(II) formate complex, RuHIir -OCOHKPHjIj,... 

Udupa, K., Subramanian, G., and Udupa, H. (1971) Xhe electrolytic reduction of carbon dioxide to formic acid. Electrochim. Acta, 16, 1593-1598. 

With respect to synthetic (in particular, catalysed) organic reactions [3,94], it is noteworthy that the first reports on the useful application of SCCO2 as a solvent and reactant were described by Noyori and coworkers [95, 96] in 1994 for the efficient ruthenium-catalysed transformations of carbon dioxide to formic acid, dimethyl formamide and methyl formate. During the last decade, SCFs have been applied for a variety of other areas of organic synthesis, including the formation of carbon-carbon bonds [80, 81,97-99]. 

Masel Rl (2012) Novel catalyst mixtures for electrochemical conversion of carbon dioxide to formic acid. US Patent Application W02012006240A1... 

Hwang DY, Mebel AM (2002) Theoretical study of TiO-catalyzed hydrogenatirai of carbon dioxide to formic acid. J Chem Phys 116 5633-5642... 

Ohnishi YY, Nakao Y, Sato H, Sakaki S (2006) Ruthenium(II)-catalyzed hydrogenation of carbon dioxide to formic acid. Theoretical study of significant acceleration by water molecules. Organometallics 25 3352-3363... 

Uhnan M, Tinnemans AHA, Mackor A, Aurian-Blajeni B, Hahnann M (1982) Photoreduction of carbon dioxide to formic acid, formaldehyde, methanol, acetaldehyde and ethanol using aqueous suspensions of strontium titanate with transition metal additives. Int J Sol Energy 1 (3) 213-222... 

Zafrir M, Ulman M, Zuckerman Y, Halmann M (1983) Photoelectrochemical reduction of carbon dioxide to formic acid, formaldehyde and methanol on p-gallium arsenide in an aqueous V(II)-V(III) chloride redox system. J Electroanal Chem 159 373-389... 

Gassner, F. Leitner, W. (1993) C02-activation. 3. Hydrogenation of carbon-dioxide to formic acid using water-soluble rhodium catalysts, Chem. Commun., 1465-6. 

Mechanism of imidazol-catalysed electrochemical reduction of carbon dioxide to formic acid. For description, refer to details in the text. (Adapted from K.A. Keets et al., Ind. ]. Chem. A, 51, 2012,1284-1297.)... 

While efficient avenues for releasing hydrogen from formic acid have been demonstrated, the efficient synthesis of formic acid continues to be a challenge [55]. This state of affairs is smprising, if one considers that the electroreduction of carbon dioxide to formic acid has been studied for more than 140 years, and the first report on the process was published by Royer as early as in 1870 [127]. By the begirming of World War 1, an additional three papers had been released [128-130]. Nevertheless, the process still needs to be optimised for energy efficiency and selectivity [131,132]. 

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