Processes for synthesizing borohydride compounds

• US 6,670,444 B2
• Filed: 12/27/2002
• Issued: 12/30/2003
• Est. Priority Date: 11/08/2000
• Status: Expired due to Fees

• Current Assignee: Millennium Cell Inc.
• Original Assignee: Millennium Cell Inc.
• Inventors: Wu, Ying, Ortega, Jeffrey V., Kelly, Michael T., Amendola, Steven C.
• Primary Examiner(s): Truong, Duc
• Application Number:
  US10/331,674
• Publication Number:
  US 20030092877A1
• Time in Patent Office: 368 Days
• Field of Search: 528/394, 528/240, 528/241, 528/482, 528/486, 528/488, 528/493, 528/495, 528/503
• US Class Current: 528/394
• CPC Class Codes: C01B 2203/0227 containing a catalytic reforming step
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 3/34 by reaction of hydrocarbons with gasifying agents
• CPC Class Codes: C01B 6/13 Addition complexes of monoborane or diborane, e.g. with phosphine, arsine or hydrazine
• CPC Class Codes: C01B 6/19 Preparation from other compounds of boron
• CPC Class Codes: C01B 6/21 Preparation of borohydrides of alkali metals, alkaline earth metals, magnesium or beryllium; Addition complexes thereof, e.g. LiBH4.2N2H4, NaB2H7
• CPC Class Codes: F17C 11/005 for hydrogen
• CPC Class Codes: Y02E 60/32 Hydrogen storage
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials

Abstract

The present invention relates to processes for producing borohydride compounds. In particular, the present invention provides efficient processes and compositions for the large-scale production of borohydride compounds of the formula YBH₄ by the reaction of a boron-containing compound represented by the formula BX₃ with hydrogen or an aldehyde to obtain diborane and HX, and reacting the diborane with a Y-containing base selected from those represented by the formula Y₂O, YOH and Y₂CO₃ to obtain YBH₄ and YBO₂. Y is selected from the group consisting of the alkali metals, pseudo-alkali metals, alkaline earth metals, an ammonium ion, and quaternary amines of the formula NR₄⁺, wherein each R is independently selected from hydrogen and a straight- or branched-chain C_1-4 alkyl group, and X is selected from the group consisting of halide ions, —OH, —R′ and —OR′ groups, chalcogens, and chalcogenides, wherein R′ is a straight- or branched-chain C_1-4 alkyl group.

Claims

1. A process for producing borohydride compounds represented by the formula YBH₄, comprising:

(A) reacting a boron-containing compound represented by the formula BX₃ with hydrogen or an aldehyde selected from the group consisting of formaldehyde, benzaldehyde, acetaldehyde, and mixtures thereof to obtain diborane; and

(B) reacting the diborane with a Y-containing base selected from those represented by the formula Y₂O, YOH and Y₂CO₃ to obtain YBH₄ and YBO₂,

wherein Y is selected from the group consisting of the alkali metals, pseudo-alkali metals, alkaline earth metals, an ammonium ion, and quaternary amines of the formula NR₄⁺, wherein each R is independently selected from hydrogen and a straight- or branched-chain C_1-4 alkyl group; and

wherein X is selected from the group consisting of halide ions, —

OH, —

R′ and

—

OR′

groups, chalcogens, and chalcogenides, wherein R′

is a straight- or branched-chain C_1-4 alkyl group.

2. A process in accordance with claim 1, wherein Y is selected from the group consisting of Na⁺, Li₊, K⁺, Mg₊₊ and Ca⁺⁺ and X is selected from the group consisting of a halide ion and —

OR′

.

3. A process in accordance with claim 1, wherein the Y-containing base represented by the formula Y₂O, and the boron-containing compound of formula BX₃ are obtained by a process comprising:

reacting a borate of the formula YBO₂ with CO₂ and an alcohol to obtain YHCO₃ and BX₃; and

converting the YHCO₃ to Y₂O by heating to a temperature from about 400°

to about 1000°

C.,

wherein X is an −

OR′

group.

4. A process in accordance with claim 3, wherein Y is sodium and said borate is represented by the formula Na₂O·

xB₂O₃·

yH₂O, wherein x is 1 to 5 and y is 0 to 10.

5. A process in accordance with claim 1, wherein the Y-containing base is represented by the formula Y₂CO₃, and the boron-containing compound of formula BX₃ are obtained by the process comprising:

reacting a borate of the formula YBO₂ with CO₂ and an alcohol to obtain YHCO₃ and BX₃; and

converting the YHCO₃ to Y₂CO₃ at a temperature from about 50°

to about 120°

C. wherein X is an —

OR′

group.

6. A process in accordance with claim 5, wherein Y is sodium and said borate is represented by the formula Na₂O·

xB₂O₃·

yH₂O, wherein x is 1 to 5 and y is 0 to 10.

7. A process in accordance with claim 1, wherein, in step (A), BX₃ is reacted with hydrogen.

8. A process in accordance with claim 1, wherein in step (B), said base is Y₂CO₃, the reaction is carried out in an aqueous solution of said base at a temperature of from about −

5°

C. to about 20°

C. and said solution contains from about 0.1 to 10 molar equivalents of said base for every molar equivalent of diborane present.

10. A process in accordance with claim 8 further comprising agitating the gaseous diborane and the base during the reaction.

11. A process in accordance with claim 10, wherein said gaseous diborane and said base are agitated in a ball mill during said reaction.

9. A process for producing borohydride compounds represented by the formula YBH₄, comprising reacting gaseous diborane in the absence of solvent with a Y-containing base selected from those represented by the formula Y₂O, YOH and Y₂CO₃ to obtain YBH₄ and YBO₂, wherein Y is selected from the group consisting of the alkali metals, pseudo-alkali metals, alkaline earth metals, an ammonium ion and quaternary amines of the formula NR₄⁺, wherein each R is independently selected from hydrogen and a straight- or branched-chain C_1-4 alkyl group.

12. A process in accordance with claim 9, wherein Y is selected from the group consisting of Na⁺, Li⁺, K⁺, Mg⁺⁺ and Ca⁺⁺.

13. A process in accordance with claim 9, wherein diborane and said base are reacted at a temperature between about −

5°

C. and about 100°

C. for from about 30 seconds to about 100 hours.

14. A process in accordance with claim 9, wherein from about 0.1 and about ten molar equivalents of said base are present for every molar equivalent of diborane.

15. A process in accordance with claim 9, wherein diborane and said base are reacted at a pressure between about 14 psi and about 200 psi.

16. A process for producing borohydride compounds represented by the formula YBH₄, comprising reacting gaseous diborane with a Y-containing base in suspension in a nonaqueous aprotic solvent or a nonaqueous polar solvent, said base being selected from those represented by the formula Y₂O, YOH and Y₂CO₃ to obtain YBH₄ and YBO₂, wherein Y is selected from the group consisting of the alkali metals, pseudo-alkali metals, alkaline earth metals, an ammonium ion and quaternary amines of the formula NR₄⁺, wherein each R is independently selected from hydrogen and a straight- or branched-chain C_1-4 alkyl group.

17. A process in accordance with claim 16 further comprising agitating said suspension during the reaction.

18. A process in accordance with claim 17, wherein said suspension is agitated in a ball mill during said reaction.

19. A process in accordance with claim 16, wherein Y is selected from the group consisting of Na⁺, Li⁺, K⁺, Mg⁺⁺ and Ca⁺⁺.

20. A process in accordance with claim 16, wherein diborane and said base are reacted at a temperature between about −

30°

C. and about 80°

C. for from about 30 seconds to about 70 hours.

21. A process in accordance with claim 16, wherein from about 0.1 and about ten molar equivalents of said base are present for every molar equivalent of diborane.

22. A process in accordance with claim 16, wherein the non-aqueous solvent is a glyme.