Catalytic Hydrogenation of Carbon Dioxide to Formic Acid

Abstract In recent years, the utilization of carbon dioxide as alternative C 1 building block has gained more and more scientific interest and has been intensely investigated. Especially the homogeneously catalyzed hydrogenation of carbon dioxide to formic acid and its derivates has been well studied. Recently, an increase in product formation was achieved by further development of the homogeneous catalysts. Currently, iridium-based catalysts offer the highest catalytic activity known in the hydrogenation of carbon dioxide. The present chapter gives a wide overview of various catalyst systems, which have been investigated so far. In addition, current research on the continuously operated hydrogenation of carbon dioxide in miniplant scale with a promising concept for catalyst recycling is presented.

[1]  Arno Behr,et al.  Verfahrenskonzepte für die übergangsmetallkatalysierten Synthesen von Ameisensäure und Dimethylformamid auf der Basis von Kohlendioxid , 2003 .

[2]  L. H. Slaugh,et al.  Formamides from carbon dioxide, amines and hydrogen in the presence of metal complexes , 1970 .

[3]  Kwok‐yin Wong,et al.  Intramolecular N−H···H−Ru Proton−Hydride Interaction in Ruthenium Complexes with (2-(Dimethylamino)ethyl)cyclopentadienyl and (3-(Dimethylamino)propyl)cyclopentadienyl Ligands. Hydrogenation of CO2 to Formic Acid via the N−H···H−Ru Hydrogen-Bonded Complexes , 1998 .

[4]  M. Aresta,et al.  Utilisation of CO2 as a chemical feedstock: opportunities and challenges. , 2007, Dalton transactions.

[5]  Y. Himeda Highly efficient hydrogen evolution by decomposition of formic acid using an iridium catalyst with 4,4′-dihydroxy-2,2′-bipyridine , 2009 .

[6]  S. Fukuzumi,et al.  Aqueous hydrogenation of carbon dioxide catalysed by water-soluble ruthenium aqua complexes under acidic conditions. , 2004, Chemical communications.

[7]  T. Ikariya,et al.  Water-Soluble Trialkylphosphine-Ruthenium(II) Complexes as Efficient Catalysts for Hydrogenation of Supercritical Carbon Dioxide. , 2001 .

[8]  S. Sakaki,et al.  Theoretical study of rhodium(III)-catalyzed hydrogenation of carbon dioxide into formic acid. Significant differences in reactivity among rhodium(III), rhodium(I), and ruthenium(II) complexes. , 2002, Journal of the American Chemical Society.

[9]  A. Baiker Utilization of carbon dioxide in heterogeneous catalytic synthesis , 2000 .

[10]  A. Urakawa,et al.  Towards a rational design of ruthenium CO2 hydrogenation catalysts by Ab initio metadynamics. , 2007, Chemistry.

[11]  G. Laurenczy,et al.  Homogeneous hydrogenation of aqueous hydrogen carbonate to formate under mild conditions with water soluble rhodium(I)- and ruthenium(II)-phosphine catalysts , 2000 .

[12]  Y. Inoue,et al.  Synthesis of formates from alcohols, carbon dioxide, and hydrogen catalysed by a combination of group VIII transition-metal complexes and tertiary amines , 1975 .

[13]  S. Sahin,et al.  Investigation of Formic Acid Separation from Aqueous Solution by Reactive Extraction: Effects of Extractant and Diluent , 2010 .

[14]  Arno Behr,et al.  Advances in thermomorphic liquid/liquid recycling of homogeneous transition metal catalysts , 2008 .

[15]  Chunshan Song Global challenges and strategies for control, conversion and utilization of CO2 for sustainable development involving energy, catalysis, adsorption and chemical processing , 2006 .

[16]  Raymond Ziessel,et al.  Photochemical and Electrochemical Reduction of Carbon Dioxide to Carbon Monoxide Mediated by (2,2′‐Bipyridine)tricarbonylchlororhenium(I) and Related Complexes as Homogeneous Catalysts , 1986 .

[17]  F. Joó,et al.  Hydrogenation of aqueous mixtures of calcium carbonate and carbon dioxide using a water-soluble rhodium(I)-tertiary phosphine complex catalyst , 2004 .

[18]  M. Saito,et al.  Ruthenium complex catalysed hydrogenation of carbon dioxide to carbon monoxide, methanol and methane , 1993 .

[19]  W. Herrmann,et al.  Water‐Soluble Ligands, Metal Complexes, and Catalysts: Synergism of Homogeneous and Heterogeneous Catalysis , 1993 .

[20]  Walter Leitner,et al.  Chemical synthesis using supercritical fluids , 1999 .

[21]  A. Behr,et al.  Temperaturgesteuerte Mehrkomponenten‐Lösungsmittelsysteme für homogene übergangsmetallkatalysierte Reaktionen , 2005 .

[22]  Thomas Schaub,et al.  Ein Verfahren zur Herstellung von Ameisensäure durch CO2-Hydrierung: Thermodynamik und die Rolle von CO† , 2011 .

[23]  N. Matubayasi,et al.  Controlling the equilibrium of formic acid with hydrogen and carbon dioxide using ionic liquid. , 2010, The journal of physical chemistry. A.

[24]  E. Peris,et al.  Water-soluble IrIII N-heterocyclic carbene based catalysts for the reduction of CO2 to formate by transfer hydrogenation and the deuteration of aryl amines in water. , 2011, Chemistry.

[25]  C. Lau,et al.  Hydrogenation of carbon dioxide to formic acid using a 6,6′-dichloro-2,2′-bipyridine complex of ruthenium,cis-[Ru(6,6′-Cl2bpy)2(H2O)2](CF3SO3)2 , 1995 .

[26]  Shengping Wang,et al.  Hydrogenation of CO2 to formic acid on supported ruthenium catalysts , 2011 .

[27]  K. Nicholas,et al.  Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid , 1992 .

[28]  Xiaoming Zheng,et al.  Silica immobilized ruthenium catalyst used for carbon dioxide hydrogenation to formic acid (I): the effect of functionalizing group and additive on the catalyst performance , 2004 .

[29]  D. Bruce,et al.  Homogeneous catalysts based on water-soluble phosphines , 2003 .

[30]  P. Jessop,et al.  Catalytic Production of Dimethylformamide from Supercritical Carbon Dioxide , 1994 .

[31]  P. Edwards,et al.  Turning carbon dioxide into fuel , 2010, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[32]  Katalyse für die chemische Wasserstoffspeicherung , 2011 .

[33]  Ryoji Noyori,et al.  Homogeneous Hydrogenation of Carbon Dioxide , 1995 .

[34]  Mårten S. G. Ahlquist,et al.  Iridium catalyzed hydrogenation of CO2 under basic conditions—Mechanistic insight from theory ☆ , 2010 .

[35]  Rolf-Peter Breinbauer Angewandte homogene Katalyse , 2008 .

[36]  A. Behr,et al.  Hydroaminomethylation in thermomorphic solvent systems , 2005 .

[37]  J. Dupont,et al.  Decomposition of Formic Acid Catalyzed by a Phosphine‐Free Ruthenium Complex in a Task‐Specific Ionic Liquid , 2010 .

[38]  G. Evans,et al.  Conversion of CO2, H2, and alcohols into formate esters using anionic iron carbonyl hydrides , 1978 .

[39]  Miniplants: Ein Beitrag zur inhärenten Sicherheit? , 2000 .

[40]  M. Aresta Carbon dioxide as chemical feedstock , 2010 .

[41]  Jürgen Klankermayer,et al.  Hydrogenation of Carbon Dioxide to Methanol by Using a Homogeneous Ruthenium–Phosphine Catalyst , 2012 .

[42]  G. Clarkson,et al.  Insights into hydrogen generation from formic acid using ruthenium complexes , 2009 .

[43]  M. Beller,et al.  Catalytic Generation of Hydrogen from Formic acid and its Derivatives: Useful Hydrogen Storage Materials , 2010 .

[44]  Martina Peters,et al.  Chemical technologies for exploiting and recycling carbon dioxide into the value chain. , 2011, ChemSusChem.

[45]  S. Sakaki,et al.  Theoretical Study of Ruthenium-Catalyzed Hydrogenation of Carbon Dioxide into Formic Acid. Reaction Mechanism Involving a New Type of σ-Bond Metathesis , 2000 .

[46]  Mark W. Farlow,et al.  The Hydrogenation of Carbon Dioxide and a Correction of the Reported Synthesis of Urethans , 1935 .

[47]  Y. Himeda,et al.  Simultaneous Tuning of Activity and Water Solubility of Complex Catalysts by Acid−Base Equilibrium of Ligands for Conversion of Carbon Dioxide , 2007 .

[48]  Gábor Papp,et al.  Homogeneous hydrogenation of carbon dioxide and bicarbonate in aqueous solution catalyzed by water-soluble ruthenium(II) phosphine complexes , 2003 .

[49]  S. Sakaki,et al.  Ruthenium(II)-catalyzed hydrogenation of carbon dioxide to formic acid. Theoretical study of real catalyst, ligand effects, and solvation effects. , 2005, Journal of the American Chemical Society.

[50]  P. Jessop,et al.  High-pressure combinatorial screening of homogeneous catalysts: hydrogenation of carbon dioxide. , 2003, Inorganic chemistry.

[51]  P. Jessop,et al.  Hydrogenation of Carbon Dioxide Catalyzed by Ruthenium Trimethylphosphine Complexes: A Mechanistic Investigation Using High-Pressure NMR Spectroscopy , 2009 .

[52]  W. Leitner,et al.  Activation of carbon dioxide: IV. Rhodium-catalysed hydrogenation of carbon dioxide to formic acid☆ , 1994 .

[53]  R. Puddephatt,et al.  The interconversion of formic acid and hydrogen/carbon dioxide using a binuclear ruthenium complex catalyst , 2000 .

[54]  W. Qin,et al.  Extraction of Monocarboxylic Acids with Trioctylamine: Equilibria and Correlation of Apparent Reactive Equilibrium Constant , 2003 .

[55]  W. Leitner,et al.  Continuous-flow hydrogenation of carbon dioxide to pure formic acid using an integrated scCO2 process with immobilized catalyst and base. , 2012, Angewandte Chemie.

[56]  W. Leitner,et al.  Direct formation of formic acid from carbon dioxide and dihydrogen using the [{Rh(cod)Cl}2]–Ph2P(CH2)4PPh2 catalyst system , 1992 .

[57]  P. Jessop,et al.  HOMOGENEOUS CATALYSIS IN SUPERCRITICAL FLUIDS : HYDROGENATION OF SUPERCRITICAL CARBON DIOXIDE TO FORMIC ACID, ALKYL FORMATES, AND FORMAMIDES , 1996 .

[58]  H. Sugihara,et al.  Recyclable catalyst for conversion of carbon dioxide into formate attributable to an oxyanion on the catalyst ligand. , 2005, Journal of the American Chemical Society.

[59]  Fenglin Liao,et al.  Morphology-dependent interactions of ZnO with Cu nanoparticles at the materials' interface in selective hydrogenation of CO2 to CH3OH. , 2011, Angewandte Chemie.

[60]  S. Fukuzumi,et al.  Accelerating effect of a proton on the reduction of CO2 dissolved in water under acidic conditions. Isolation, crystal structure, and reducing ability of a water-soluble ruthenium hydride complex. , 2003, Journal of the American Chemical Society.

[61]  J. E. Lyons,et al.  Catalysis research of relevance to carbon management: progress, challenges, and opportunities. , 2001, Chemical reviews.

[62]  A. Behr Kohlendioxid als alternativer C1‐Baustein: Aktivierung durch Übergangsmetallkomplexe , 1988 .

[63]  P. Jessop,et al.  Methyl formate synthesis by hydrogenation of supercritical carbon dioxide in the presence of methanol , 1995 .

[64]  R. Ludwig,et al.  Iron-catalyzed hydrogen production from formic acid. , 2010, Journal of the American Chemical Society.

[65]  P. Jessop,et al.  Homogeneous catalytic hydrogenation of supercritical carbon dioxide , 1994, Nature.

[66]  M. Saito,et al.  Reverse Water-Gas Shift Reaction Catalyzed by Ruthenium Cluster Anions. , 1994 .

[67]  M. Beller,et al.  Moderne Katalysatoren zur Hydrierung von Kohlendioxid , 2010 .

[68]  W. Leitner,et al.  Hydrogenation of carbon dioxide to formic acid using water-soluble rhodium catalyststs , 1993 .

[69]  Hiroyuki Yasuda,et al.  Transformation of carbon dioxide. , 2007, Chemical reviews.

[70]  I. Shimizu,et al.  Synthesis of the first carbon dioxide coordinated palladium(0) complex, Pd(η2-CO2)(PMePh2)2 , 1994 .

[71]  B. P. Sullivan,et al.  Electrochemical and electrocatalytic reactions of carbon dioxide , 1993 .

[72]  W. Qin,et al.  Liquid−Liquid Equilibria of Aqueous Acetic Acid Derivatives with Trioctylamine and Select Organic Diluents , 2003 .

[73]  C. Resta,et al.  Carbon dioxide hydrogenation to formic acid by using a heterogeneous gold catalyst. , 2011, Angewandte Chemie.

[74]  S. Enthaler,et al.  Carbon dioxide--the hydrogen-storage material of the future? , 2008, ChemSusChem.

[75]  W. M. Ayers Catalytic activation of carbon dioxide , 1988 .

[76]  E. Peris,et al.  '(eta(6)-arene)Ru(bis-NHC)' complexes for the reduction of CO(2) to formate with hydrogen and by transfer hydrogenation with iPrOH. , 2010, Dalton transactions.

[77]  Aaron J. Sathrum,et al.  Electrocatalytic and homogeneous approaches to conversion of CO2 to liquid fuels. , 2009, Chemical Society reviews.

[78]  F. Joó,et al.  Free formic acid by hydrogenation of carbon dioxide in sodium formate solutions , 2011 .

[79]  W. Leitner Kohlendioxid als Rohstoff am Beispiel der Synthese von Ameisensäure und ihren Derivaten , 1995 .

[80]  P. Wegner,et al.  Catalytic hydrogenation of carbon dioxide with the cationic bis(chelate)rhodium complex [Rh(P⌢O)2][BPh4] , 1997 .

[81]  Y. Himeda Conversion of CO2 into Formate by Homogeneously Catalyzed Hydrogenation in Water: Tuning Catalytic Activity and Water Solubility through the Acid–Base Equilibrium of the Ligand , 2007 .

[82]  A. Behr,et al.  Isomerizing hydroformylation of trans-4-octene to n-nonanal in multiphase systems: acceleration effect of propylene carbonate , 2005 .

[83]  H. H. Karsch Funktionelle Trimethylphosphinderivate, III. Ambivalentes Verhalten von Tetrakis(trimethylphosphin)eisen : Reaktion mit CO2 , 1977 .

[84]  F. Joó Breakthroughs in hydrogen storage--formic Acid as a sustainable storage material for hydrogen. , 2008, ChemSusChem.

[85]  M. Yamashita,et al.  Catalytic hydrogenation of carbon dioxide using Ir(III)-pincer complexes. , 2009, Journal of the American Chemical Society.

[86]  W. Leitner,et al.  Complexes [(P2)Rh(hfacac)](P2= bidentate chelating phosphane, hfacac = hexafluoroacetylacetonate) as catalysts for CO2 hydrogenation: correlations between solid state structures, 103Rh NMR shifts and catalytic activities , 1995 .

[87]  T. Schmidt,et al.  Carbon Dioxide and Formic Acid - The couple for an environmental-friendly hydrogen storage? , 2010 .

[88]  K. Wagner Reactions with Addition Compounds Containing Activated Formic Acid , 1970 .

[89]  A. Behr Carbon Dioxide Activation by Metal Complexes , 1988 .

[90]  W. Leitner,et al.  Mechanistic Aspects of the Rhodium-Catalyzed Hydrogenation of CO2 to Formic AcidA Theoretical and Kinetic Study†,‖ , 1997 .

[91]  Olivier Jacquet,et al.  A diagonal approach to chemical recycling of carbon dioxide: organocatalytic transformation for the reductive functionalization of CO2. , 2012, Angewandte Chemie.

[92]  B. Rieger,et al.  Umwandlung von Kohlendioxid mit Übergangsmetall‐Homogenkatalysatoren: eine molekulare Lösung für ein globales Problem? , 2011 .

[93]  G. Laurenczy,et al.  Formation and characterization of water-soluble hydrido-ruthenium(II) complexes of 1,3,5-triaza-7-phosphaadamantane and their catalytic activity in hydrogenation of CO2 and HCO3- in aqueous solution. , 2000, Inorganic chemistry.

[94]  J. Cole,et al.  Rhodium nitrosyl catalysts for CO2 hydrogenation to formic acid under mild conditions , 2012 .

[95]  J. Dietrich,et al.  Kinetische Untersuchungen zur Hydrierung von Kohlendioxid zu Ameisensäure mit einem Rhodiumkomplex als Katalysator , 2008 .

[96]  B. Han,et al.  Hydrogenation of CO2 to formic acid promoted by a diamine-functionalized ionic liquid. , 2009, ChemSusChem.

[97]  Kwok‐yin Wong,et al.  Promoting Effect of Water in Ruthenium-Catalyzed Hydrogenation of Carbon Dioxide to Formic Acid , 2001 .

[98]  S. Fukuzumi,et al.  Mechanistic investigation of CO2 hydrogenation by Ru(II) and Ir(III) aqua complexes under acidic conditions: two catalytic systems differing in the nature of the rate determining step. , 2006, Dalton transactions.

[99]  D. Darensbourg,et al.  Anionic group 6B metal carbonyls as homogeneous catalysts for carbon dioxide/hydrogen activation: the production of alkyl formates , 1984 .

[100]  G. Laurenczy,et al.  Homogeneous hydrogenation of aqueous hydrogen carbonate to formate under exceedingly mild conditions—a novel possibility of carbon dioxide activation† , 1999 .

[101]  Y. Chang,et al.  Effect of pH on the extraction characteristics of succinic and formic acids with Tri-n-octylamine dissolved in 1-octanol , 2001 .

[102]  C. Y. Tsang,et al.  Phase equilibria in the H2/CO2 system at temperatures from 220 to 290 K and pressures to 172 MPa , 1981 .

[103]  Takeshi Kobayashi,et al.  Unusually large tunneling effect on highly efficient generation of hydrogen and hydrogen isotopes in pH-selective decomposition of formic acid catalyzed by a heterodinuclear iridium-ruthenium complex in water. , 2010, Journal of the American Chemical Society.

[104]  C. Bo,et al.  Carbon dioxide interaction with pentacarbonylhydridochromate(1-): theoretical study of the thermodynamic aspects , 1989 .

[105]  A. Behr,et al.  Applied Homogeneous Catalysis , 2012 .

[106]  P. Jessop,et al.  Reactions of transition metal dihydrogen complexes , 1992 .

[107]  C. Lau,et al.  Ruthenium-Catalyzed Hydrogenation of Carbon Dioxide to Formic Acid in Alcohols , 2004 .

[108]  F. Kühn,et al.  Recycling CO2? Computational Considerations of the Activation of CO2 with Homogeneous Transition Metal Catalysts , 2012 .

[109]  M. Beller,et al.  Catalytic hydrogenation of carbon dioxide and bicarbonates with a well-defined cobalt dihydrogen complex. , 2012, Chemistry.

[110]  C. King,et al.  Solvent equilibriums for extraction of carboxylic acids from water , 1978 .

[111]  M. Klein,et al.  Hydrogen evolution from formic acid in an ionic liquid solvent: a mechanistic study by ab initio molecular dynamics. , 2011, The journal of physical chemistry. B.

[112]  M. Beller,et al.  Ruthenium-catalyzed hydrogenation of bicarbonate in water. , 2010, ChemSusChem.

[113]  M. Saito,et al.  Homogeneous Hydrogenation of Carbon Dioxide to Methanol Catalyzed by Ruthenium Cluster Anions in the Presence of Halide Anions , 1995 .

[114]  Elisabetta Alberico,et al.  Asymmetric transfer hydrogenation: chiral ligands and applications. , 2006, Chemical Society reviews.

[115]  A. Behr Verwendung von Kohlendioxid bei technischorganischen Synthesen , 1985 .

[116]  Jun Zhang,et al.  Homogeneous catalytic synthesis of formic acid (salts) by hydrogenation of CO2 with H2 in the presence of ruthenium species , 1996 .

[117]  M. Beller,et al.  Ein wohldefinierter Eisenkatalysator für die Reduktion von Bicarbonaten und Kohlendioxid zu Formiaten, Alkylformiaten und Formamiden , 2010 .

[118]  S. B. Halligudi,et al.  Reduction of CO2 by molecular hydrogen to formic acid and formaldehyde and their decomposition to CO and H2O , 1989 .

[119]  Y. Inoue,et al.  CATALYTIC FIXATION OF CARBON DIOXIDE TO FORMIC ACID BY TRANSITION-METAL COMPLEXES UNDER MILD CONDITIONS , 1976 .

[120]  M. Haga,et al.  Selective formation of HCO2– and C2O42– in electrochemical reduction of CO2 catalyzed by mono- and di-nuclear ruthenium complexes , 1998 .

[121]  Liang Zhao,et al.  Decomposition of Formic Acid in Supercritical Water , 2010 .

[122]  Atsushi Urakawa,et al.  Carbon dioxide hydrogenation catalyzed by a ruthenium dihydride: a DFT and high-pressure spectroscopic investigation. , 2007, Chemistry.

[123]  Xinzheng Yang Hydrogenation of Carbon Dioxide Catalyzed by PNP Pincer Iridium, Iron, and Cobalt Complexes: A Computational Design of Base Metal Catalysts , 2011 .

[124]  Iwao Omae,et al.  Aspects of carbon dioxide utilization , 2006 .

[125]  P. Dyson,et al.  Direct, in situ determination of pH and solute concentrations in formic acid dehydrogenation and CO(2) hydrogenation in pressurised aqueous solutions using (1)H and (13)C NMR spectroscopy. , 2013, Dalton transactions.

[126]  A. Behr,et al.  Rhodium-catalysed synthesis of branched fatty compounds in temperature-dependent solvent systems , 2003 .

[127]  I. Willner,et al.  Artificial photosynthetic model systems using light-induced electron transfer reactions in catalytic and biocatalytic assemblies , 1991 .

[128]  Ning Yan,et al.  Selective formic acid decomposition for high-pressure hydrogen generation: a mechanistic study. , 2009, Chemistry.

[129]  T. Hirose,et al.  Interconversion between formic acid and H(2)/CO(2) using rhodium and ruthenium catalysts for CO(2) fixation and H(2) storage. , 2011, ChemSusChem.

[130]  E. V. Slivinskii,et al.  Hydrogenation of CO2 to formic acid in the presence of the Wilkinson complex , 2002 .

[131]  G. Fachinetti,et al.  Conversion of Syngas into Formic Acid , 2012 .

[132]  P. Jessop,et al.  Hydrogenation of carbon dioxide catalyzed by ruthenium trimethylphosphine complexes: the accelerating effect of certain alcohols and amines. , 2002, Journal of the American Chemical Society.

[133]  W. Leitner,et al.  σ Metathesis as a Critical Step for the Transition Metal Catalyzed Formation of Formic Acid from CO2 and H2? An Ab Initio Investigation , 1995 .

[134]  Y. Diskin‐Posner,et al.  Low-pressure hydrogenation of carbon dioxide catalyzed by an iron pincer complex exhibiting noble metal activity. , 2011, Angewandte Chemie.

[135]  Frederick W. Williams,et al.  Heterogeneous catalytic CO2 conversion to value-added hydrocarbons , 2010 .

[136]  B. Brunschwig,et al.  Mechanistic and kinetic studies of cobalt macrocycles in a photochemical CO2 reduction system: Evidence of Co-CO2 adducts as intermediates , 1995 .

[137]  G. Laurenczy,et al.  Towards an easy carbon dioxide reduction in aqueous solution , 2000 .

[138]  W. Leitner,et al.  [()2RhH]‐ und [()2 Rh] [O2 CH]‐Komplexe als Modelle für die Katalytisch aktiven Zwischenstufen der Rh‐Katalysierten Hydrierung von CO2 zu HCOOH , 1993 .

[139]  K. Weissermel,et al.  Industrial Organic Chemistry , 1978 .

[140]  M. Beller,et al.  Continuous Hydrogen Generation from Formic Acid: Highly Active and Stable Ruthenium Catalysts , 2009 .

[141]  R. Ludwig,et al.  Efficient Dehydrogenation of Formic Acid Using an Iron Catalyst , 2011, Science.

[142]  A. Baiker,et al.  Ruthenium-catalysed formylation of amines with dense carbon dioxide as C1-source , 2003 .

[143]  A. Behr,et al.  Scale‐up durch Miniplant‐Technik: Anwendungsbeispiele aus der homogenen Katalyse , 2012 .

[144]  Zhongyuan Zhou,et al.  Synthesis, characterization and reactivity of heterobimetallic complexes (η5-C5R5)Ru(CO)(μ-dppm)M(CO)2(η5-C5H5)(R = H, CH3; M = Mo, W). Interconversion of hydrogen/carbon dioxide and formic acid by these complexes , 2003 .

[145]  G. Süss-Fink,et al.  Arene ruthenium oxinato complexes: Synthesis, molecular structure and catalytic activity for the hydrogenation of carbon dioxide in aqueous solution , 2009 .

[146]  H. Sugihara,et al.  Half-Sandwich Complexes with 4,7-Dihydroxy-1,10-phenanthroline: Water-Soluble, Highly Efficient Catalysts for Hydrogenation of Bicarbonate Attributable to the Generation of an Oxyanion on the Catalyst Ligand , 2004 .