HYDROGEN STORAGE AND DELIVERY MATERIAL

Abstract

The present invention provides novel diamine-monoborane liquid organic hydrogen carriers with hydrogen storage capacities at least equivalent to prior art hydrogen carriers. The novel diamine-monoboranes of the invention provide advantages over the prior art including low cost due to the simple one-step chemical synthesis method between a diamine and a borane complex, and that the starting materials are inexpensive compared to the prior art. The novel diamine-monoboranes of the invention provide excellent dehydrogenation performance. With the presence of inexpensive and readily-available commercial catalysts, dehydrogenation occurs at ambient temperatures and pressures with high hydrogen purity. The resulting 1,3,2-diazaborolidines (cyclic diaminoboranes) are readily hydrogenated to produce the novel diamine-monoboranes of the invention. The invention also provides use of the diamine-monoboranes of the invention in a fuel cell or a portable power cell, or cell installed in conjunction with a hydrogen-burning engine. Other uses relate to transport down pipelines and in tankers.

Claims

1. A compound having a structure represented by Formula III: ##STR00015## wherein A is optional, if the A is not present, each of R.sup.1 and R.sup.2 is individually selected from H, OH, C.sub.1-C.sub.6 alkyl, substituted C.sub.1-C.sub.6 alkyl, C.sub.3-8 cycloalkyl, substituted C.sub.3-8 cycloalkyl, C.sub.1-C.sub.6 alkoxy, substituted C.sub.1-C.sub.6 alkoxy, amino with a structure NR.sup.6R.sup.7, cyano with a structure CN, carbocyclylalkyl with a structure including (CH.sub.2).sub.n-Ph in which n=0-6, halogen, C.sub.6-10 aryl, or substituted C.sub.6-10 aryl, or if the A is present, the A is selected from (CH.sub.2).sub.n in which n=1-6, O, C(O), S, S(O), or CHR.sup.8, and each of R.sup.1 and R.sup.2 is individually selected from bridging C.sub.1-C.sub.6 alkyl, bridging substituted C.sub.1-C.sub.6 alkyl, bridging C.sub.1-C.sub.6 alkoxy, bridging substituted C.sub.1-C.sub.6 alkoxy, bridging amino with a structure NR.sup.6, bridging C.sub.6-10 aryl, or bridging substituted C.sub.6-10 aryl; wherein each of R.sup.3 and R.sup.4 is individually selected from H, OH, a C.sub.1-C.sub.6 alkyl, cycloalkyl, haloalkyl, C.sub.1-C.sub.6 acyl, NH.sub.2, CN, or SiR.sup.9; wherein R.sup.5 is selected from H, C.sub.1-C.sub.6 alkyl, NH.sub.2, CN, or OH; wherein each of R.sup.6 and R.sup.7 is independently selected from H, C.sub.1-C.sub.6 alkyl, or substituted C.sub.1-C.sub.6 alkyl; wherein R.sup.8 is selected from C.sub.1-C.sub.6 alkyl, halogen, C.sub.1-C.sub.6 alkoxy, C.sub.1-C.sub.6 alkoxy-substituted C.sub.1-C.sub.6 alkyl, or amino with a structure NR.sup.6R.sup.7; wherein R.sup.9 is selected from halogen, amino with a structure NR.sup.6R.sup.7, alkoxy, or (CH.sub.2).sub.n-Ph in which n=0-6, and wherein each of X, Y and Z is independently selected from (CH.sub.2).sub.n in which n=0-6, O, C(O), S, S(O), or CHR.sup.8.

2. (canceled)

3. (canceled)

4. The compound of claim 1, having a structure represented by Formula IV: ##STR00016## wherein each of R.sup.1 and R.sup.2 is individually selected from H, OH, C.sub.1-C.sub.6 alkyl, substituted C.sub.1-C.sub.6 alkyl, C.sub.3-8 cycloalkyl, substituted C.sub.3-8 cycloalkyl, C.sub.1-C.sub.6 alkoxy, substituted C.sub.1-C.sub.6 alkoxy, amino with a structure NR.sup.6R.sup.7, cyano with a structure CN, carbocyclylalkyl with a structure including (CH.sub.2).sub.n-Ph in which n=0-6, halogen, C.sub.6-10 aryl, or substituted C.sub.6-10 aryl; wherein each of R.sup.3 and R.sup.4 is individually selected from H, OH, C.sub.1-C.sub.6 alkyl, cycloalkyl, haloalkyl, C.sub.1-C.sub.6 acyl, NH.sub.2, CN, or SiR.sup.9; wherein R.sup.5 is selected from H, C.sub.1-C.sub.6 alkyl, NH.sub.2, CN, or OH; wherein each of R.sup.6 and R.sup.7 is independently selected from H, C.sub.1-C.sub.6 alkyl, or substituted C.sub.1-C.sub.6 alkyl; wherein R.sup.8 is selected from C.sub.1-C.sub.6 alkyl, halogen, C.sub.1-C.sub.6 alkoxy, C.sub.1-C.sub.6 alkoxy-substituted C.sub.1-C.sub.6 alkyl, or amino with a structure NR.sup.6R.sup.7; wherein R.sup.9 is selected from halogen, amino, alkoxy, or (CH.sub.2).sub.n-Ph in which n=0-6; and wherein X is selected from (CH.sub.2).sub.n in which n=0-6, O, C(O), S, S(O), or CHR.sup.8.

5. (canceled)

6. The compound of claim 1, wherein at least one of: each of the R.sup.1 and the R.sup.2 is individually selected from methyl or ethyl, and each of the R.sup.3 and the R.sup.4 is individually selected from methyl or ethyl.

7. (canceled)

8. The compound of claim 1, having a structure represented by Formula I: ##STR00017## wherein each of R.sup.1 and R.sup.2 is individually selected from H, C1-C6 alkyl, C1-C6 alkoxy, NH2, cyano with a structure CN, or halogen.

9. The compound of claim 1, having a structure represented by Formula I, ##STR00018## wherein R.sup.1 and R.sup.2 are both H.

10. (canceled)

11. (canceled)

12. The compound of claim 1, wherein the compound is a liquid at 20 C. and 1 atmosphere.

13. The compound of claim 1 wherein the compound has a hydrogen capacity at a gravimetric density of between about 3.0 and 6.0 wt % or a volumetric density of at least 35 g H.sub.2/L.

14. (canceled)

15. (canceled)

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. A method of preparing a diamine-monoborane compound, the method comprising the steps of: reacting a compound having a structure represented by Formula VI with at least one of BH.sub.3, B.sub.2H.sub.6, BH.sub.3.THF, BH.sub.3.SMe.sub.2, and disiamylborane to obtain the compound having the structure represented by the Formula III according to claim 1, ##STR00019## wherein A is optional, if the A is not present, each of R.sup.1 and R.sup.2 is individually selected from H, OH, C.sub.1-C.sub.6 alkyl, substituted C.sub.1-C.sub.6 alkyl, C.sub.3-8 cycloalkyl, substituted C.sub.3-8 cycloalkyl, C.sub.1-C.sub.6 alkoxy, substituted C.sub.1-C.sub.6 alkoxy, amino with a structure NR.sup.6R.sup.7, cyano with a structure CN, carbocyclylalkyl with a structure including (CH.sub.2).sub.n-Ph in which n=0-6, halogen, C.sub.6-10 aryl, or substituted C.sub.6-10 aryl; or if the A is present, the A is selected from (CH.sub.2).sub.n in which n=1-6, O, C(O), S, S(O), or CHR.sup.8, and each of R.sup.1 and R.sup.2 is individually selected from bridging C.sub.1-C.sub.6 alkyl, bridging substituted C.sub.1-C.sub.6 alkyl, bridging C.sub.1-C.sub.6 alkoxy, bridging substituted C.sub.1-C.sub.6 alkoxy, bridging amino with a structure NR.sup.6, bridging C.sub.6-10 aryl, or bridging substituted C.sub.6-10 aryl; and wherein each of R.sup.3 and R.sup.4 is individually selected from H, OH, a C.sub.1-C.sub.6 alkyl, cycloalkyl, haloalkyl, C.sub.1-C.sub.6 acyl, NH.sub.2, CN, or SiR.sup.9; wherein each of R.sup.6 and R.sup.7 is independently selected from H, C.sub.1-C.sub.6 alkyl, or substituted C.sub.1-C.sub.6 alkyl; wherein R.sup.8 is selected from C.sub.1-C.sub.6 alkyl, halogen, C.sub.1-C.sub.6 alkoxy, C.sub.1-C.sub.6 alkoxy-substituted C.sub.1-C.sub.6 alkyl, or amino with a structure NR.sup.6R.sup.7; wherein R.sup.9 is selected from halogen, amino with a structure NR.sup.6R.sup.7, alkoxy, or (CH.sub.2).sub.n-Ph in which n=0-6; and wherein each of X, Y and Z is independently selected from (CH.sub.2).sub.n in which n=0-6, O, C(O), S, S(O), or CHR.sup.8.

21. (canceled)

22. (canceled)

23. The method of claim 20, wherein the reaction is conducted at room temperature for 24 hours.

24. A method for reversibly storing and releasing hydrogen, the method comprising the steps of: a) providing a diamine-monoborane compound having a structure represented by Formula III which is capable of reversible dehydrogenation and hydrogenation; b) contacting the diamine-monoborane compound under reaction conditions sufficient to release gaseous hydrogen from the diamine-monoborane compound and produce at least partially dehydrogenated 1,3,2-diazaborolidine; and c) recovering the gaseous hydrogen, wherein Formula III has the structure: ##STR00020## wherein A is optional, if the A is not present, each of R.sup.1 and R.sup.2 is individually selected from H, OH, C.sub.1-C.sub.6 alkyl, substituted C.sub.1-C.sub.6 alkyl, C.sub.3-8 cycloalkyl, substituted C.sub.3-8 cycloalkyl, C.sub.1-C.sub.6 alkoxy, substituted C.sub.1-C.sub.6 alkoxy, amino with a structure NR.sup.6R.sup.7, cyano with a structure CN, carbocyclylalkyl with a structure including (CH.sub.2).sub.n-Ph in which n=0-6, halogen, C.sub.6-10 aryl, or substituted C.sub.6-10 aryl; or if the A is present, the A is selected from (CH.sub.2).sub.n in which n=1-6, O, C(O), S, S(O), or CHR.sup.8, and each of R.sup.1 and R.sup.2 is individually selected from bridging C.sub.1-C.sub.6 alkyl, bridging substituted C.sub.1-C.sub.6 alkyl, bridging C.sub.1-C.sub.6 alkoxy, bridging substituted C.sub.1-C.sub.6 alkoxy, bridging amino with a structure NR.sup.6, bridging C.sub.6-10 aryl, or bridging substituted C.sub.6-10 aryl; and wherein each of R.sup.3 and R.sup.4 is individually selected from H, OH, a C.sub.1-C.sub.6 alkyl, cycloalkyl, haloalkyl, C.sub.1-C.sub.6 acyl, NH.sub.2, CN, or SiR.sup.9; wherein R.sup.5 is selected from H, C.sub.1-C.sub.6 alkyl, NH.sub.2, CN, or OH; wherein each of R.sup.6 and R.sup.7 is independently selected from H, C.sub.1-C.sub.6 alkyl, or substituted C.sub.1-C.sub.6 alkyl; wherein R.sup.8 is selected from C.sub.1-C.sub.6 alkyl, halogen, C.sub.1-C.sub.6 alkoxy, C.sub.1-C.sub.6 alkoxy-substituted C.sub.1-C.sub.6 alkyl, or amino with a structure NR.sup.6R.sup.7; wherein R.sup.9 is selected from halogen, amino with a structure NR.sup.6R.sup.7, alkoxy, or (CH.sub.2).sub.n-Ph in which n=0-6; and wherein each of X, Y and Z is independently selected from (CH.sub.2).sub.n in which n=0-6, O, C(O), S, S(O), or CHR.sup.8.

25. The method of claim 24, further comprising the steps of: d) contacting the at least partially dehydrogenated 1,3,2-diazaborolidine under conditions to hydrogenate the dehydrogenated 1,3,2-diazaborolidine to produce a diamine-monoborane compound having a structure represented by the Formula III, and e) recovering the produced diamine-monoborane compound having the structure represented by the Formula III.

26. The method of claim 24, wherein the step b) reaction conditions include heating the diamine-monoborane compound at a temperature from 20 to 150 C. to affect release of at least one dihydrogen equivalent.

27. (canceled)

28. The method of claim 24, wherein the step b) reaction conditions include a catalytic reaction to absorb or release hydrogen, the catalytic reaction comprising contacting the diamine-monoborane compound with a catalyst at a temperature from about 20 to 200 C.

29. (canceled)

30. The method of claim 28, wherein the catalyst is at least one of: a metal halide catalyst selected from CoCl.sub.2, CuCl.sub.2, NiCl.sub.2, FeCl.sub.3 and FeCl.sub.2, a catalyst comprising one or more platinum group metals selected from the group consisting of: platinum, palladium, rhodium, ruthenium, and iridium, and a catalyst comprising nickel.

31. (canceled)

32. The method of claim 28, wherein the catalyst is [RuH.sub.2(.sup.2-H.sub.2).sub.2(PCy.sub.3).sub.2].

33. The method of claim 24, wherein the dehydrogenated 1,3,2-diazaborolidine has a structure represented by Formula V: ##STR00021##

34. The method of claim 24, wherein the dehydrogenated 1,3,2-diazaborolidine is a liquid at 20 C. and 1 atmosphere, and remains in the liquid phase until being hydrogenated in step d).

35. (canceled)

36. The method of claim 24, wherein at least one of: each of the R.sup.1 and the R.sup.2 is individually selected from methyl or ethyl, and each of the R.sup.3 and the R.sup.4 is individually selected from methyl or ethyl.

37. The method of claim 24, wherein the diamine-monoborane compound in step a) has a structure represented by Formula I: ##STR00022## wherein each of R.sup.1 and R.sup.2 are individually selected from H, C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.6 alkoxy, NH.sub.2, cyano with a structure CN, or halogen.

38. The method of claim 37, wherein the R.sup.1 and the R.sup.2 are both H.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0123] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.

[0124] FIG. 1 is a .sup.1H NMR of the ethylenediamine mono-borane of the invention; and

[0125] FIG. 2 is an .sup.11B NMR of ethylenediamine mono-borane.

[0126] FIG. 3 shows the crystal structure of ethylenediamine monoborane determined by X-ray single crystal diffraction analysis: a) molecular packing in a unit cell; b) one single molecule. Atom key: large blackboron; dark greycarbon; small blacknitrogen; light greyhydrogen.

DEFINITIONS

[0127] In describing and claiming the present invention, the following terminology has been used in accordance with the definitions set out below. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.

[0128] Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of including, but not limited to.

[0129] The terms preferred and preferably refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0130] Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term about.

[0131] The recitation of a numerical range using endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0132] The term alkyl means all variants possible for each number of carbon atoms in the alkyl group i.e. methyl, ethyl, for three carbon atoms: n-propyl and isopropyl; for four carbon atoms: n-butyl, isobutyl and tertiary-butyl; for five carbon atoms: n-pentyl, 1,1-dimethyl-propyl, 2,2-dimethylpropyl and 2-methyl-butyl, etc.

[0133] Unless otherwise specified a substituted or unsubstituted alkyl group is preferably a C.sub.1 to C.sub.6-alkyl group.

[0134] Acyl refers to a group having the structure R(O)C, where R may be alkyl, or substituted alkyl. Lower acyl groups are those that contain one to six carbon atoms.

[0135] The term substituted, in e.g. substituted alkyl group means that the alkyl group may be substituted by other atoms than the atoms normally present in such a group, i.e. carbon and hydrogen. For example, a substituted alkyl group may include a halogen atom or a thiol group. An unsubstituted alkyl group contains only carbon and hydrogen atoms.

[0136] The term alkoxy refers to a straight, branched or cyclic hydrocarbon configuration that include an oxygen atom at the point of attachment. An example of an alkoxy group is represented by the formula OR, where R can be an alkyl group. Suitable alkoxy groups include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, sec-butoxy, tert-butoxy cyclopropoxy, cyclohexyloxy, and the like.

[0137] Unless otherwise specified a substituted alkyl group, a substituted cycloalkyl group, a substituted aryl group and a substituted alkoxy group are preferably substituted by one or more constituents selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tertiary-butyl, ester group, amide group, ether group, thioether group, ketone group, aldehyde group, sulfoxide group, sulfone group, sulfonate ester group, sulphonamide group, Cl, Br, I, OH, SH, CN and NO.sub.2.

[0138] The term halogen refers to fluoro, bromo, chloro and iodo substituents.

[0139] The term amino, unless defined otherwise, refers to a group of the formula NRR, where R and R can be, each independently, hydrogen or a C.sub.1-C.sub.6 alkyl.

[0140] The term carbocyclylalkyl, as used herein, refers to an alkyl group substituted with a carbocycle group.

[0141] The terms carbocycle and carbocyclyl, as used herein, refer to a non-aromatic saturated or unsaturated ring in which each atom of the ring is carbon. Preferably a carbocycle ring contains from 3 to 10 atoms, more preferably from 5 to 7 atoms.

[0142] The prior art referred to in this specification is incorporated herein by reference.

PREFERRED EMBODIMENT OF THE INVENTION

[0143] The present invention will now be described with reference to the following examples which should be considered in all respects as illustrative and non-restrictive.

Synthesis of Ethylenediamine Mono-Borane

[0144] A dry vial was charged with 1 eq ethylenediamine and then placed into an ice-bath. The compound BH.sub.3.THF (1eq) was added slowly via syringe. The reaction solution was left to stir at room temperature for 24 hours. THF was removed by evaporation at reduced pressure and the resultant oily liquid was thrice washed using hexanes. The mixture then was dissolved in chloroform. The product was analysed by .sup.1H NMR and .sup.11B NMR spectra (FIG. 1. and FIG. 2, respectively). A crystal structure of the resultant product is shown in FIG. 3.

Dehydrogenation Reaction

[0145] Dehydrogenation experiments were undertaken using commercially available catalysts, such as Pd/C, and the purity of the evolved hydrogen gas was determined via mass spectrometer and gas chromatography. When 1 wt. % Pd/C was added to the liquid ethylenediamine mono-borane of the invention, only dihydrogen molecules were detected being released from the liquid. High purity H.sub.2 was released from the liquid at temperatures below 100 C. (at 50 C.) with fast kinetics, which is highly compatible with standard hydrogen fuel cell. The hydrogen capacity of the ethylenediamine mono-borane of the invention is 5 wt %, making it an ideal candidate for long distance, large scale energy storage and delivery via the well-established fuel transportation infrastructure.

[0146] The novel compounds of the present invention possess properties which make them suitable candidates to meet at least some of the following requirements: good hydrogen-storage efficiency and capacity relative to the weight of the material; good absorption/desorption rate; good dissociation equilibrium pressure; suitable desorption temperature/pressure; good repeated absorption-desorption cycles without significant loss of its hydrogen storage capabilities (i.e. reversibility); good hydrogenation/dehydrogenation kinetics to enable hydrogen to be absorbed or desorbed in a relatively short period of time; good resistance to poisoning by contaminants to which the material may be subjected during manufacturing and utilization; little or no hysteresis issues; no phase change upon H.sub.2 desorption; a liquid under ambient conditions (e.g., at 20 C. and 1 atm pressure); and good air stability; complete or almost complete release of H.sub.2 over a wide variety of commercial catalysts.

[0147] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. In particular features of any one of the various described examples may be provided in any combination in any of the other described examples.