Dihydrogen Production Process

Abstract

The present invention relates to a process for producing dihydrogen from formic acid. It also relates to the use of the dihydrogen produced by the process of the invention, in a fuel cell, in a combustion engine, in the production of ammonia and methanol, in oil refining, and in the metallurgy, electronics and food sectors. The invention also relates to an energy production process comprising a step of producing dihydrogen from formic acid by the process according to the invention.

Claims

1. A process fey of producing dihydrogen from formic acid, wherein formic acid is brought into contact: with at least one catalyst (i) said catalyst being a Lewis acid selected from organic or inorganic boron compounds selected from BF.sub.3, BF.sub.3(Et.sub.2O), BCl.sub.3, diphenyl hydroborane, dicyclohexyl hydroborane, chlorodicyclohexylborane, 9-iodo-9-borabicyclo[3.3.1]nonane (BBNI), B-chlorocatecholborane, B(C.sub.6F.sub.5).sub.3, B-methoxy-9-borabicyclo[3.3.1]nonane (B-methoxy-9-BBN), B-benzyl-9-borabicyclo[3.3.1]nonane, Me-TBD-BBN.sup.+I.sup., Me-TBD-BBN.sup.+CF.sub.3SO.sub.3.sup., (TDB-BBN).sub.2, TBD-BBN-CO.sub.2, TBD-BBN-BBN, [TBDH.sup.+ BBN(OCHO).sub.2.sup.], [Et.sub.3NH.sup.+Cy.sub.2B(OCHO).sub.2.sup.]; organic or inorganic silicon compounds selected from SiCl.sub.4, Me.sub.3SiCl, Et.sub.3Si.sup.+and Me.sub.3Si.sup.+; divalent or tetravalent organic or inorganic germanium compounds selected from GeCl.sub.2, GeBr.sub.2, GeCl.sub.4, Ge(OEt.sub.2).sub.4, Me.sub.3GeCl, Me.sub.2ClGe.sup.+, Et.sub.3Ge.sup.+and Me.sub.3Ge.sup.+; organic or inorganic tin compounds with oxidation state +IV or +II selected from SnCl.sub.2, SnCl.sub.4, nBu.sub.2SnCl.sub.2, Cy.sub.3SnCl, Bu.sub.3SnH, tBu.sub.2SnCl.sub.2, nBuSnCl.sub.3, Me.sub.2SnCl, SnBu.sub.4, tetraisopropoxystannane, tetrakis(acetyloxy)stannane, Me.sub.3SnCl, Et.sub.3Sn.sup.+and Me.sub.3Sn.sup.+; oxoniums selected from (CH.sub.3).sub.3O.sup.+and (CH.sub.3CH.sub.2).sub.3O.sup.+; carbocations selected from the trityl cation ((C.sub.6H.sub.5).sub.3C.sup.+), tropylium (C.sub.7H.sub.7).sup.+, the benzyl cation (C.sub.6H.sub.5CH.sub.2.sup.+), allyl cation (CH.sub.3CH.sup.+CHCH.sub.2), methylium (CH.sub.3.sup.+) and cyclopropylium (C.sub.3H.sub.5.sup.+); with the anionic counterion of the silylium cations, oxoniums, carbocations, stannic cations and germanium cations being a halide selected from F.sup., Cl.sup., Br.sup. and I.sup., or an anion selected from BF.sub.4.sup., SbF.sub.6.sup., B(C.sub.6F.sub.5).sub.4.sup., B(C.sub.6H.sub.5).sub.4.sup., CF.sub.3SO.sub.3.sup. or TfO.sup. and P F.sub.6.sup.; with at least one compound selected from (ii) an organic base selected from nitrogen-containing organic bases, phosphorus-containing organic bases, carbon-containing bases, and oxygen-containing organic bases; and/or (iii) a halide salt.

2. The process as claimed in claim 1, wherein (i) the Lewis acid is selected from a derivative of formula R.sub.2BX where R is a saturated linear, branched or cyclic alkyl group, optionally substituted, comprising 1 to 12 carbon atoms, and X is selected from the halides Cl.sup., Br.sup., I.sup., the alkoxides such as methoxide OMe or ethoxide OEt, OTf, NTf.sub.2 or else H; BF.sub.3, BF.sub.3(Et.sub.2O), BCl.sub.3, diphenyl hydroborane, dicyclohexyl hydroborane, chlorodicyclohexylborane, 9-iodo-9-borabicyclo[3.3.1]nonane (BBNI), B-chlorocatecholborane, B(C.sub.6F.sub.5).sub.3, B-methoxy-9-borabicyclo[3.3.1]nonane (B-methoxy-9-BBN), B-benzyl-9-borabicyclo[3.3.1]nonane, Me-TBD-BBN.sup.+I.sup., Me-TBD-BBN.sup.+CF.sub.3SO.sub.3.sup.', (TDB-BBN).sub.2, TBD-BBN-CO.sub.2, TBD-BBN-BBN, [TBDH.sup.+, BBN(OCHO).sub.2.sup.], [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.]; SnCl.sub.2, SnCl.sub.4, nBu.sub.2SnCl.sub.2, Cy.sub.3SnCl, Bu.sub.3SnH, tBu.sub.2SnCl.sub.2, nBuSnCl.sub.3, Me.sub.2SnCl, SnBu.sub.4, tetraisopropoxystannane, tetrakis(acetyloxy)stannane, Me.sub.3SnCl, Et.sub.3Sn.sup.+ and Me.sub.3Sn.sup.+; with the anionic counterion of the stannic and stannous cations being a noncoordinating anion selected from BF.sub.4.sup., SbF.sub.6.sup., B(C.sub.6F.sub.5).sub.4.sup., B(C.sub.6H.sub.5).sub.4.sup., CF.sub.3SO.sub.3.sup. or TfO.sup. and PF.sub.6.sup., or a halide selected from F.sup., Cr.sup., Br.sup. and I.sup..

3. The process as claimed in claim 1, wherein (ii) the organic base is selected from: - nitrogen-containing organic bases which are secondary or tertiary amines selected from triazabicyclodecene (TBD); N-methyltriazabicyclodecene (Me-TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), trimethylamine, triethylamine, piperidine, 4-dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), proline, phenylalanine, a thiazolium salt, N-diisopropylethylamine (DIPEA or DIEA); phosphorus-containing organic bases which are alkyl or aryl phosphines selected from triphenylphosphine, 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP), triisopropylphosphine, 1,2-bis(diphenylphosphino)ethane (dppe), tricyclohexylphosphine (PCy.sub.3); alkyl and aryl phosphonates selected from diphenylphosphate, triphenylphosphate (TPP), tri(isopropylphenyl)phosphate (TIPP), cresyldiphenyl phosphate (CDP), tricresylphosphate (TCP); alkyl and aryl phosphates selected from di-n-butylphosphate (DBP), tris-(2-ethylhexyl)phosphate, triethyl phosphate; alkyl and aryl phosphinites and phosphonites selected from methyldiphenylphosphinite and methyldiphenylphosphonite, the aza-phosphines selected from 2,8,9-thisopropyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (BV.sup.Me) and 2,8,9-thisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (BV.sup.IBI; carbon-containing bases selected from N-heterocyclic carbenes derived from an imidazolium salt, said carbenes being selected from the salts of 1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-3-ium, 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-1H-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 4,5-dichloro-1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-3-ium, 1,3 di tert butyl 1H 1,3-di-tert-butyl-4,5-dihydro-1H-imidazol-3-ium, said salts being in the form of chloride salts; oxygen-containing bases selected from hydrogen peroxide; benzoyl peroxide; pyridine oxide (PyO), N-methylmorpholine oxide and 1-A.sup.1-oxidanyl-2,2,6,6-tetramethylpiperidine.

4. The process as claimed in claim 1, wherein (ii) the organic base is a nitrogen-containing organic base selected from triazabicyclodecene (TBD); N-methyltriazabicyclodecene (Me-TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), trimethylamine, triethylamine, piperidine, 4-dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), proline, phenylalanine, a thiazolium salt, N-diisopropylethylamine (DIPEA or DIEA).

5. The process as claimed in claim 1, wherein (iii) the halide salt is selected from the chloride, bromide, iodide and fluoride salts, said halide salts being selected from NaF, NaCl, NaBr, Nal, KCl, LiCl, [(n-Bu.sub.4)N.sup.+,F.sup.], [(n-Bu.sub.4)N.sup.+, Cl.sup.], [(n-Bu.sub.4)N.sup.+,Br.sup.], [(n-Bu.sub.4)N.sup.+,I.sup.], [PPh.sub.4.sup.+,F.sup.], [PPh.sub.4.sup.+,Cl.sup.], [PPh.sub.4.sup.+,Br.sup.] and [PPh.sub.4.sup.+,I.sup.].

6. The process as claimed in claim 1, wherein formic acid is brought into contact with (i) a Lewis acid as defined in one of claim 1 or 2 selected from: a derivative of formula R.sub.2BX where R is a saturated linear, branched or cyclic alkyl group, optionally substituted, comprising 1 to 12 carbon atoms, and X is selected from the halides Cl.sup., Br.sup., I.sup., the alkoxides such as methoxide OMe or ethoxide OEt, OTf, NTf.sub.2 or else H; BF.sub.3, BF.sub.3(Et.sub.2O), BCl.sub.3, diphenyl hydroborane, dicyclohexyl hydroborane, chlorodicyclohexylborane, 9-iodo-9-borabicyclo[3.3.1]nonane (BBNI), B-chlorocatecholborane, B(C.sub.6F.sub.5).sub.3, B-methoxy-9-borabicyclo[3.3.1]nonane (B-methoxy-9-BBN), B-benzyl-9-borabicyclo[3.3.1]nonane, Me-TBD-BBN.sup.30I.sup., Me-TBD-BBN.sup.+CF.sub.3SO.sub.3.sup., (TDB-BBN).sub.2, TBD-BBN-CO.sub.2, TBD-BBN-BBN, [TBDH.sup.+, BBN(OCHO).sub.2.sup.], [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.]; SnCl.sub.2, SnCl.sub.4, nBu.sub.2SnCl.sub.2, Cy.sub.3SnCl, Bu.sub.3SnH, tBu.sub.2SnCl.sub.2, nBuSnCl.sub.3, Me.sub.2SnCl, SnBu.sub.4, tetraisopropoxystannane, tetrakis(acetyloxy)stannane, Me.sub.3SnCl, Et.sub.3Sn.sup.+and Me.sub.3Sn.sup.+; with the anionic counterion of the stannic and stannous cations being a noncoordinating anion selected from BF.sub.4.sup., SbF.sub.6.sup., B(C.sub.6F.sub.5).sub.4.sup., B(C.sub.6H.sub.5).sub.4.sup., CF.sub.3SO.sub.3.sup. or TfO.sup. and PF.sub.6.sup., or a halide selected from F.sup., Cl.sup., Br.sup. and I.sup.,and (ii) an organic base selected from triazabicyclodecene (TBD); N-methyltriazabicyclodecene (Me-TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), trimethylamine, triethylamine, piperidine, 4-dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), proline, phenylalanine, a thiazolium salt, N-diisopropylethylamine (DIPEA or DIEA), and (iii) a halide salt selected from the chloride, bromide, iodide and fluoride salts, said halide salts being selected from NaF, NaCl, NaBr, Nal, KCl, LiCl, [(n-Bu.sub.4)N.sup.+,F.sup.], [(n-Bu.sub.4)N.sup.+, Cl.sup.], [(n-Bu.sub.4)N.sup.+,Br.sup.], [(n-Bu.sub.4)N.sup.+,I.sup.], [PPh.sub.4.sup.+,F.sup.], [PPh.sub.4.sup.+,Cl.sup.], [PPh.sub.4.sup.+,Br.sup.] and [PPh.sub.4.sup.+,I.sup.].

7. The process as claimed in claim 1, additionally using at least one basic additive selected from organic amines selected from triethylamine, piperidine and 4-dimethylaminopyridine, ammonia and ammonium, carbon-containing inorganic bases selected from carbonate salts CO.sub.3.sup.2 and hydrogen carbonate salts HCO.sub.3.sup., said carbonate salts CO.sub.3.sup.2 and hydrogen carbonate salts HCO3 being selected from CaCO.sub.3 and NaHCO.sub.3, oxygen-containing inorganic bases selected from the hydroxide salts HO.sup., said hydroxide salts being selected from KOH and NaOH.

8. The process as claimed in claim 1, wherein the amount of basic additive used is from 0.1 to 1 molar equivalent, inclusive, relative to the number of moles of formic acid.

9. The process as claimed in claim 1, wherein production of dihydrogen takes place at a pressure of CO.sub.2, H.sub.2, dinitrogen (N.sub.2), argon or a mixture of at least two of these gases.

10. The process as claimed in claim 1, wherein production of dihydrogen takes place at a pressure between 0.1 and 75 bar.

11. The process as claimed in claim 1, wherein the temperature of the reaction of formic acid with the catalyst is between 15 and 150 C.

12. The process as claimed in claim 1, wherein the duration of the reaction of formic acid with the catalyst optionally in the presence of a basic additive is from 5 minutes to 200 hours,

13. The process as claimed in claim 1, wherein the reaction is carried out in a solvent or a mixture of at least two solvents selected from: water; ethanol or ethylene glycol; diethyl ether, or THF; benzene, or toluene; pyridine, or acetonitrile; dimethylsulfoxide; chloroform, or methylene chloride; supercritical CO.sub.2.

14. The process as claimed in claim 1, wherein the amount of catalyst is from 0.0001 to 1 molar equivalent, relative to the number of moles of formic acid.

15. (canceled)

16. A process of producing energy, wherein it comprises a step of producing dihydrogen from formic acid by the process as claimed in claim 1.

17. The process as claimed in claim 10, wherein production of dihydrogen takes place at a pressure between 0.1 and 30 bar.

18. The process as claim in claim 10, wherein production of dihydrogen takes place at a pressure between 0.1 and 10 bar.

19. The process as claimed in claim 11, wherein the temperature of the reaction of formic acid with the catalyst is between 15 and 130 C.

20. The process as claimed in claim 12, wherein the duration of the reaction of formic acid with the catalyst optionally in the presence of a basic additive is from 10 minutes to 48 hours.

21. The process as claimed in claim 14, wherein the amount of catalyst is from 0.001 to 1 molar equivalent, relative to the number of moles of formic acid.

22. The process as claimed in claim 14, wherein the amount of catalyst is from 0.001 to 0.5 molar equivalent, relative to the number of moles of formic acid.

Description

EXAMPLES

[0155] The catalytic reaction of dehydrogenation of formic acid, presented in scheme 5, may be carried out according to the following experimental protocol: [0156] 1. Under an inert atmosphere of argon or dinitrogen, in a glove box, formic acid, the precatalyst (from 1 to 0.001 equivalent) and, optionally, the solvent and the basic additive are put in a Schlenk tube, which is then sealed with a J. Young tap. The order of introducing the reactants is not important. [0157] 2. The Schlenk is then heated at a temperature between 25 and 140 C. until there is complete conversion of formic acid (from 5 minutes to 150 hours of reaction). [0158] 3. The gases emitted may be collected during the reaction by a system of burets or else a system connected to a device using the gases that are emitted, such as a PEMFC fuel cell. Alternatively, the gases may be stored in the sealed reaction chamber if the latter is able to withstand the gas pressure generated.

##STR00008##

TABLE-US-00001 additif basique basic additive catalyseur catalyst (solvant) (solvent) temprature temperature

[0159] Various catalysts, additives, solvents and temperatures were tested for the reaction.

[0160] The catalysts Me-TBD-BBN.sup.+I.sup., (TDB-BBN).sub.2, TBD-BBN-CO.sub.2, TBD-BBN-BBN, [TBDH.sup.+, BBN(OCHO).sub.2.sup.] and [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.] were prepared according to the following protocols:

[0161] Synthesis of (TBD-BBN).sub.2

[0162] A 20-mL flask equipped with a magnetized bar and sealed with a J. Young stopper is charged with TBD (163.1 mg, 1.17 mmol, 1 eq), the dimer (9-BBN).sub.2 (143.0 mg, 0.59 mmol, 0.5 eq) and tetrahydrofuran (3.5 mL). The flask is sealed and the solution is stirred for one hour at 70 C. The reaction mixture is cooled to room temperature and then the solid is filtered on a frit and washed with diethyl ether. A white solid is recovered and is dried under reduced pressure, obtaining the product (TBD-BBN).sub.2 in a yield of 75% (194.9 mg).

[0163] Synthesis of TBD-BBN-CO.sub.2

[0164] A 20-mL flask equipped with a magnetized bar and sealed with a J. Young stopper is charged with (TBD-BBN).sub.2 (71.0 mg, 0.14 mmol) and tetrahydrofuran (4 mL). The reaction mixture is put under an atmosphere of CO.sub.2 (1 bar). The flask is sealed and the solution is stirred for 75 minutes at 100 C. The white solid in the reaction mixture gradually dissolves during heating. The reaction mixture is cooled to room temperature (about 20 C.) and then the solvent is evaporated under reduced pressure in order to recover TBD-BBN-C.sub.2 in the form of a white solid in quantitative yield (84.0 mg).

[0165] Synthesis of TBD-BBN-BBN

[0166] A 20-mL flask equipped with a magnetized bar and sealed with a J. Young stopper is charged with (TBD-BBN).sub.2 (100.0 mg, 0.19 mmol, 1 eq), the dimer (9-BBN).sub.2 (51.0 mg, 0.21 mmol, 1.1 eq) and tetrahydrofuran (5 mL). The flask is sealed and the solution is stirred for 150 minutes at 100 C. The white solid in the reaction mixture gradually dissolves during heating. The reaction mixture is cooled to room temperature and then the solvent is partially evaporated from the reaction mixture to about 0.5 mL. During evaporation of the solvent, a white solid appears. The solid is filtered on a frit and washed with cold diethyl ether (40 C.). The solid is recovered and is dried under reduced pressure, obtaining the product TBD-BBN-BBN in a yield of 76% (110.5 mg).

[0167] Synthesis of Me-TBD-BBN.sup.+I.sup.

[0168] A 20-mL flask equipped with a magnetized bar and sealed with a J. Young stopper is charged with Me-TBD (53.1 mg, 0.35 mmol, 1 eq) and tetrahydrofuran (3.5 mL). The solution is stirred and a 1M solution of 9-iodo-9-borabicyclo[3.3.1]nonane in hexane (350 L, 0.35 mmol, 1 eq) is added to the reaction mixture. A white precipitate forms immediately after adding 9-iodo-9-borabicyclo[3.3.1]nonane solution. The flask is sealed and the solution is stirred for 30 minutes at room temperature (about 20 C.). The solid is filtered on a frit and washed with diethyl ether. The solid is recovered and is dried under reduced pressure, obtaining the product Me-TBD-BBN.sup.+I.sup. in a yield of 81% (112.0 mg). [0169] .sup.1H NMR (200 MHz, CD.sub.2Cl.sub.2): 4.13 (m, 1H), 3.95 (m, 1H), 3.75 (m, 2H), 3.48 (m, 4H), 3.10 (s, 3H), 2.49-1.18 (m, 18H) ppm. [0170] .sup.C NMR (50 MHz, CD.sub.2Cl.sub.2): 158.7, 48.7, 48.4, 43.4, 41.2, 36.1, 35.5, 31.5, 30.9, 25.9, 24.9, 20.9, 20.4 ppm. [0171] .sup.11B NMR (64 MHz, CD.sub.2Cl.sub.2): 57.2 ppm. [0172] Elemental analysis: calc. for C.sub.16H.sub.29BIN.sub.3 (M 401.14 g.mol.sup.1): C: 47.91, H: 7.29, N: 10.48. Found: C: 48.26, H 6.96; N 11.63.
ORTEP View of Me-TBD-BBN.sup.+I.sup. Obtained by X-ray Diffraction.

[0173] Synthesis of [TBDH.sup.+, BBN(OCHO).sub.2.sup.].

[0174] A 25-mL flask equipped with a magnetized bar and a J-Young tap is charged with the dimer 9-BBN (342 mg, 1.4 mmol, 0.5 equiv.) and 5 mL of toluene. The suspension obtained is stirred until the solid has dissolved completely and then formic acid (258 mg, 211 L, 5.6 mmol, 2 equiv) is added using a syringe, followed by TBD (390 mg, 2.8 mmol, 1 equiv) in one go. Considerable evolution of hydrogen gas is observed. The reaction is then stirred for 2 h at room temperature and then pentane (5 mL) is added. A white solid precipitates, and the latter is then recovered by filtration and washed with pentane (32 mL). The white solid thus recovered is dried under reduced pressure, obtaining [TBDH.sup.+, BBN(OCHO).sub.2.sup.] (930 mg) in a yield of 93%. The latter can be recrystallized from a saturated toluene solution. [0175] .sup.1H NMR (200 MHz, CD.sub.3CN) 8.40 (s, 2H), 6.94 (bs, 2H), 3.23 (dd, J=11.3, 5.3 Hz, 8H), 2.06-1.21 (m, 16H), 0.72 (bs, 2H). [0176] .sup.13C NMR (50 MHz, CD.sub.3CN) 167.23, 152.07, 47.43, 38.74, 32.07, 25.62, 21.16. [0177] .sup.11B NMR (64 MHz, CD.sub.3CN) 8.87. [0178] Elemental analysis: calc. (%) for C.sub.17H.sub.30BN.sub.3O.sub.4 (351.25 g.mol.sup.1): C 58.13, H 8.61, N 11.96; found: C 58.12, H 8.58 N 12.16.
ORTEP View of [TBDH.sup.+, BBN(OCHO).sub.2.sup.] Obtained by X-Ray Diffraction.

[0179] Synthesis of [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.]

[0180] Dicyclohexylborane Cy.sub.2BH is synthesized according to a procedure described in the literature and is used without special purification.

[0181] A 25-mL flask, equipped with a magnetized bar and a J-Young tap, is charged with Cy.sub.2BH (481 mg, 2.7 mmol, 1 equiv.) and 5 mL of toluene. The suspension obtained is stirred until the solid has dissolved completely, and then formic acid (204 4, 5.4 mmol, 2 equiv) is added using a syringe, followed by Et.sub.3N (377 4, 2.7 mmol, 1 equiv) in one go. Considerable evolution of hydrogen gas is observed. The reaction is then stirred for 2 h at room temperature and then the solvent is evaporated to dryness, leaving a very viscous oil. After multiple additions of pentane and trituration of the oil in hexane, the oil crystallizes and a white solid is obtained; the latter is then recovered by filtration and washed with pentane (3 33 2 mL) and ether (32 mL). The white solid thus recovered is dried under reduced pressure, obtaining [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.] (901 mg) in a yield of 90%. .sup.1H NMR (200 MHz, CD.sub.3CN) 8.77 (s, 1H, NH), 8.29 (s, 2H, HC(O)O), 3.13 (t, J=7.2 Hz, 6H), 1.65 (d, J=4.3 Hz, 4H), 1.50 (d, J=12.8 Hz, 4H), 1.24 (t, J=7.3 Hz, 9H), 1.12 (d, J=7.6 Hz, 4H), 1.01-0.73 (m, 4H), 0.48 (tt, J=12.0 Hz, 2H, CH-B) ppm. [0182] .sup.13C NMR (50 MHz, CD.sub.3CN) 166.43, 47.39, 29.38, 28.50, 9.06 ppm. [0183] .sup.11B NMR (64 MHz, CD.sub.3CN) 11.17 ppm. [0184] Elemental analysis: calc. (%) for C.sub.20H.sub.40BNO.sub.4 (369.30 g.mol.sup.1): C 65.04, H 10.92, N 3.79; found: C 63.05, H 11.03, N 3.41.

[0185] A set of results is presented below in Table 1, giving examples of production of dihydrogen from formic acid. In all the tests carried out, CO.sub.2 is also obtained. The amount of formic acid used in all the tests is 0.2 mmol. Various catalysts were also tested.

TABLE-US-00002 TABLE 1 Amount of Reaction Conversion to catalyst Additive Temperature time H.sub.2 and CO.sub.2 TON Catalyst (mol %) Solvent (mmol) ( C.) (hours) (%) (TOF, h.sup.1) [Me-TBD- 10 THF 150 120 100 10 (0.08) BBN.sup.+I.sup.] [Me-TBD- 5 THF 130 67 100 20 (0.3) BBN.sup.+I.sup.] [Me-TBD- 2 THF 130 67 66 33 (0.5) BBN.sup.+I.sup.] [Me-TBD- 2 THF 130 91 92 46 (0.5) BBN.sup.+I.sup.] [DBU- 5 THF 130 63 95 19 (0.3) BBN.sup.+, I.sup.] BBNI 5 THF MTBD 130 18 30 7 (0.38) (0.02) PPh.sub.3 + THF 130 96 68 7 (0.07) BBNI [Me-TBD- 5 THF Et.sub.3N 130 25 52 10.4 (0.41) BBN.sup.+I.sup.] (0.08) [Me-TBD- 5 THF Et.sub.3N 130 43 100 20 (0.46) BBN.sup.+, I.sup.] (0.08) [Me-TBD- 5 MeCN Et.sub.3N 130 19 89 18 (0.94) BBN.sup.+, I.sup.] (0.08) [DBU- 5 THF Et.sub.3N 130 40 47 9 (0.23) BBN.sup.+, I.sup.] (0.08) tBu3P + 5 THF Et.sub.3N 130 22 20 4 (0.18) BBNI.sup. (0.08) BBNI 5 THF Et.sub.3N 130 19 48 9.6 (0.51) (0.08) BBNI 5 MeCN Et.sub.3N 130 19 84 16.8 (0.88) (0.08) BBNI 5 MeCN Et.sub.3N 120 19 18 3.6 (0.19) (0.08) BBN-OTf 5 MeCN Et.sub.3N 130 19 59 11.8 (0.62) (0.08) BBNOMe 5 MeCN Et.sub.3N 130 19 88 17.5 (0.92) (0.08) [TBDH.sup.+BBN 5 MeCN Et.sub.3N 130 19 67 13.4 (0.71) (OCHO).sub.2.sup.] (0.08) [TBDH.sup.+BBN 2 MeCN Et.sub.3N 130 19 59 23.6 (1.24) (OCHO).sub.2.sup.] (0.08) BBNH 5 MeCN Et.sub.3N 130 19 52 10.4 (0.55) (0.08) Cy.sub.2BI 10 MeCN Et.sub.3N 130 4.5 >99 10 (2.2) (0.08) Cy.sub.2BI 5 MeCN Et.sub.3N 130 19 >99 20 (0.52) (0.08) Cy.sub.2BI 1 MeCN Et.sub.3N 130 19 79 79 (4.16) (0.08) Cy.sub.2BI 1 MeCN Et.sub.3N 130 40 100 100 (2.5) (0.08) Cy.sub.2BCl 5 MeCN Et.sub.3N 130 19 >99 20 (0.52) (0.08) Cy.sub.2B-OTf 5 MeCN Et.sub.3N 130 19 >99 20 (0.52) (0.08) (Et.sub.3NH.sup.+, Cy.sub.2B 5 MeCN Et.sub.3N 130 8 >99 20 (2.50) (OCHO).sub.2.sup.] (0.08) (Et.sub.3NH.sup.+, Cy.sub.2B 2.5 MeCN Et.sub.3N 130 9 >99 40 (4.44) (OCHO).sub.2.sup.] (0.08) [Et.sub.3NH.sup.+, Cy.sub.2B 1 MeCN Et.sub.3N 130 19 78 78 (4.11) (OCHO).sub.2.sup.] (0.08) [Et.sub.3NH.sup.+, Cy.sub.2B 1 MeCN Et.sub.3N 130 26 100 100 (3.84) (OCHO).sub.2.sup.] (0.08) BCl.sub.3 5 MeCN Et.sub.3N 130 19 44 8.8 (0.46) (0.08) nBu.sub.2SnCl.sub.2 5 MeCN Et.sub.3N 130 18 60 12 (0.67) (0.08) nBu.sub.2SnCl.sub.2 5 MeCN Et.sub.3N 330 25 82 16.4 (0.66) (0.08) Cy.sub.3SnCl 5 MeCN Et.sub.3N 130 45 35 7 (0.16) (0.08) nBu.sub.2SnH 5 MeCN Et.sub.3N 130 45 29 5.8 (0.13) (0.08) tBuSnCl.sub.2 5 MeCN Et.sub.3N 130 45 95 19 (0.42) (0.08) nBuSnCl.sub.3 5 MeCN Et.sub.3N 130 15 40 8 (0.53) (0.08) nBuSnCl.sub.3 5 MeCN Et.sub.3N 130 25 66 13.2 (0.53) (0.08) Me.sub.2SnCl 5 MeCN Et.sub.3N 130 15 34 6.8 (0.45) (0.08) Me.sub.2SnCl 5 MeCN Et.sub.3N 130 25 41 8.2 (0.33) (0.08) SnCl.sub.2 5 MeCN Et.sub.3N 130 16 83 16.6 (1.03) (0.08)

[0186] The catalysts [TBDH.sup.+, BBN(OCHO).sub.2.sup.] and [Et.sub.3NH.sup.+, Cy.sub.2B(OCHO).sub.2.sup.] may be represented as follows:

##STR00009##

[0187] As already noted, formic acid may be converted to H.sub.2, or to a mixture of H.sub.2 and CO.sub.2, which can be separated by the methods known by a person skilled in the art, for example H.sub.2/CO.sub.2 separation by adsorption of the CO.sub.2 on ethanolamines or by cryogenic separation.

[0188] When the process of the invention results in a mixture of dihydrogen and carbon dioxide, the amount of each gas in the mixture can be determined, for example, by collecting the gases in a buret and analyzing the composition of the mixture by gas chromatography. These techniques are techniques that are commonly used in this field and are familiar to a person skilled in the art. In the above table, the yields in conversion of formic acid shown correspond to the yields in conversion of formic acid to an equimolar mixture of H.sub.2 and CO.sub.2.

[0189] At 130 C., the maximum TOF observed is 4.44 h.sup.1 and the maximum TON measured is 100 (with [Et.sub.3NH.sup.+,Cy.sub.2B(OCHO).sub.2.sup.].sup. as catalyst). These results demonstrate, for the first time, that catalysts that do not employ group IIA alkaline-earth metals, group IIIA metals, transition metals of group IB to VIIIB, rare earths or actinides may be used for promoting the production of dihydrogen from formic acid.