WO2015100157A1 - Ammonia borane purifiction method - Google Patents
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- WO2015100157A1 WO2015100157A1 PCT/US2014/071426 US2014071426W WO2015100157A1 WO 2015100157 A1 WO2015100157 A1 WO 2015100157A1 US 2014071426 W US2014071426 W US 2014071426W WO 2015100157 A1 WO2015100157 A1 WO 2015100157A1
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- ammonia borane
- basic aqueous
- aqueous solution
- solubility
- organic solvent
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- JBANFLSTOJPTFW-UHFFFAOYSA-N azane;boron Chemical compound [B].N JBANFLSTOJPTFW-UHFFFAOYSA-N 0.000 title claims abstract description 166
- 238000000034 method Methods 0.000 title claims abstract description 46
- 239000007864 aqueous solution Substances 0.000 claims abstract description 63
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims abstract description 58
- 239000003960 organic solvent Substances 0.000 claims abstract description 52
- 239000000243 solution Substances 0.000 claims abstract description 41
- 239000012535 impurity Substances 0.000 claims abstract description 27
- 229910052751 metal Inorganic materials 0.000 claims description 36
- 239000002184 metal Substances 0.000 claims description 36
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- 239000006227 byproduct Substances 0.000 claims description 29
- 150000003863 ammonium salts Chemical class 0.000 claims description 28
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 24
- 238000002156 mixing Methods 0.000 claims description 19
- 238000003786 synthesis reaction Methods 0.000 claims description 14
- VQBIMXHWYSRDLF-UHFFFAOYSA-M sodium;azane;hydrogen carbonate Chemical compound [NH4+].[Na+].[O-]C([O-])=O VQBIMXHWYSRDLF-UHFFFAOYSA-M 0.000 claims description 13
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical class N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 8
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- 238000000638 solvent extraction Methods 0.000 claims description 6
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 claims description 5
- 229910001853 inorganic hydroxide Inorganic materials 0.000 claims description 5
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 4
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 claims description 4
- 230000001376 precipitating effect Effects 0.000 claims description 4
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 4
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 claims description 3
- 229960004132 diethyl ether Drugs 0.000 claims description 3
- 125000001033 ether group Chemical group 0.000 claims 3
- 238000005192 partition Methods 0.000 claims 3
- 230000000593 degrading effect Effects 0.000 claims 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims 1
- 239000000908 ammonium hydroxide Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract description 14
- 238000000354 decomposition reaction Methods 0.000 abstract description 4
- 230000007423 decrease Effects 0.000 abstract description 4
- 239000003125 aqueous solvent Substances 0.000 description 32
- 239000002904 solvent Substances 0.000 description 15
- 238000000746 purification Methods 0.000 description 14
- 239000012071 phase Substances 0.000 description 8
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 239000002244 precipitate Substances 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 239000001099 ammonium carbonate Substances 0.000 description 5
- 235000012501 ammonium carbonate Nutrition 0.000 description 5
- 239000012279 sodium borohydride Substances 0.000 description 5
- 229910000033 sodium borohydride Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- WZMUUWMLOCZETI-UHFFFAOYSA-N azane;borane Chemical compound B.N WZMUUWMLOCZETI-UHFFFAOYSA-N 0.000 description 2
- 238000010923 batch production Methods 0.000 description 2
- 239000003518 caustics Substances 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- -1 for example Chemical compound 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical compound N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 description 1
- 239000005695 Ammonium acetate Substances 0.000 description 1
- 239000012448 Lithium borohydride Substances 0.000 description 1
- 229910003203 NH3BH3 Inorganic materials 0.000 description 1
- 238000005481 NMR spectroscopy Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229940043376 ammonium acetate Drugs 0.000 description 1
- 235000019257 ammonium acetate Nutrition 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- VZTDIZULWFCMLS-UHFFFAOYSA-N ammonium formate Chemical compound [NH4+].[O-]C=O VZTDIZULWFCMLS-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 150000001642 boronic acid derivatives Chemical class 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 229940052303 ethers for general anesthesia Drugs 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000002608 ionic liquid Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 239000012454 non-polar solvent Substances 0.000 description 1
- 238000010943 off-gassing Methods 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000012066 reaction slurry Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
- 239000013638 trimer Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B35/00—Boron; Compounds thereof
- C01B35/08—Compounds containing boron and nitrogen, phosphorus, oxygen, sulfur, selenium or tellurium
- C01B35/14—Compounds containing boron and nitrogen, phosphorus, sulfur, selenium or tellurium
- C01B35/146—Compounds containing boron and nitrogen, e.g. borazoles
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Definitions
- This invention is directed to a method of purifying ammonia borane, which includes the steps of forming a mixture of (a) a solution of crude ammonia borane in an organic solvent and (b) a basic aqueous solution, at conditions under which impurities present in the crude ammonia borane, such as sodium ammonium carbonate, are substantially more soluble in the aqueous solution than is the ammonia borane. After the impurities are extracted or caused to precipitate from the organic solvent, the organic solvent containing ammonia borane is phase separated from the basic aqueous solution. Ammonia borane having a purity of 99% or greater can be recovered from the organic solvent layer.
- Ammonia borane also referred to as ammonium borane and borazane
- ammonia borane has been investigated as an energy-dense source of hydrogen, for example, for use in hydrogen related power generation.
- Methods of synthesis of ammonia borane are disclosed in amachandran et al. US 2007/0243122 Al (“Ramachandran”). Briefly, the process involves reacting a metal borohydride with an ammonia salt, in a suitable solvent. For example, sodium borohydride is reacted with ammonium carbonate in an ether solvent, such as tetrahydrofuran (“THF”) or dioxane.
- THF tetrahydrofuran
- the solution is filtered and the solvent is removed under vacuum to yield solid ammonia borane.
- the recovered ammonia borane powder may be purified by extraction with a suitable solvent, followed by removal of the solvent under reduced pressure, to yield a solid ammonia borane of relatively high purity.
- metal ammonium salts such as sodium ammonium carbonate
- metal ammonium salts are a significant byproduct of the synthesis reaction between a metal borohydride and an ammonia salt. Isolating ammonia borane from metal ammonium salts and other byproducts of the reaction has proven difficult in the past, due to the difficulty of filtering byproducts that have precipitated in the reaction slurry and due to the similar solubilities of ammonia borane and the byproducts in a range of polar and non-polar solvents.
- the utility of ammonia borane as a hydrogen storage medium is linked to its ability to release H 2 over a wide range conditions, including in the presence of ionic liquids and bases. Accordingly, purification of crude ammonia borane is limited to conditions that do not trigger decomposition of the ammonia borane and 3 ⁇ 4 release.
- An object of the invention is to provide high-purity ammonia borane, for example, ammonia borane having a purity of 99% or higher, by weight.
- Another object of the invention is to provide an ammonia borane purification method, whereby crude ammonia borane is treated to remove impurities, while the ammonia borane is dissolved in an organic solvent.
- Yet another object of the invention is provide a purification method that may be used with a solution of crude ammonia borane in the organic ether in which the ammonia borane is synthesized.
- Still another object of the invention is to employ a basic aqueous solution to extract, digest and or precipitate impurities present in crude ammonia borane, at conditions under which the solubility of ammonia borane in the aqueous solution is minimal.
- Another object of the invention is to provide a method of ammonia borane purification that is economical to operate commercially and can be adapted to either a batch or continuous process.
- the process may be employed to purify crude ammonia borane produced by any of a variety of synthetic processes.
- the crude ammonia borane may be in the form of an isolated solid, such as a dry powder or a wet filter cake, or the crude ammonia borane may be suspended in a suitable organic liquor.
- Ammonia borane can be synthesized in an organic ether, with the resulting crude ammonia borane dissolved therein.
- the crude ammonia borane solution can be advantageously used directly in the present purification process, without the need to first isolate the ammonia borane from the organic solvent.
- the crude ammonia borane can be dissolved in a suitable organic solvent and purified according to the method herein.
- the purification process is conducted with the crude ammonia borane dissolved in an organic solvent, such as an organic ether, referred to herein as the crude ammonia borane solution.
- the solution contains impurities, including byproducts from the synthesis of ammonia borane.
- the byproducts are typically metal ammonium salts, produced by the reaction of a metal borohydride and an ammonia salt in an organic ether, such as sodium ammonium carbonate, as well as unreacted starting material, dimers, trimers, and other self-condensation products, and other borates.
- the impurities exhibit a wide range of solubilities in the organic solvent, that is, a particular impurity may be insoluble, partially soluble or soluble in the organic solvent.
- the crude ammonia borane solution is mixed with a basic aqueous solution, to form a two-phase system.
- the basic aqueous solution may be an alkali metal hydroxide or an alkaline earth metal hydroxide.
- the pH may range from 8 to 14.
- the crude ammonia borane solution and the basic aqueous solution are mixed at conditions under which the impurities present in the organic solvent are separated by partitioning into the basic aqueous solvent or precipitating from the mixture.
- Another feature of the process is that some of the impurities can be decomposed by or react with the basic aqueous solvent and such reactants can also be extracted by the basic aqueous solvent, evolve as a gas or precipitate.
- the step of separating the impurities from the organic solvent is intended to include the impurities present in the crude ammonia borane solution, as well as any decomposition products or reactants derived from the impurities that are extracted into the basic aqueous solution, precipitated from or evolved from the mixture.
- the pH of the basic aqueous solvent for example the concentration of the hydroxide, the volume of the basic aqueous solvent and the temperature at which the mixing and separation step is conducted are selected to increase the solubility of the impurities in the basic aqueous solvent, especially the metal ammonium salts, and decrease the solubility of ammonia borane in the basic aqueous solution.
- the mixing and separation step may be effectively conducted at temperatures ranging from 20 to 50 °C.
- the objectives of the invention have been achieved when the mixing and separation step is conducted for 10 minutes or more.
- the mixture is allowed to phase separate and the organic solvent phase containing dissolved ammonia borane is separated from the basic aqueous solvent and precipitates.
- the ammonia borane may then be isolated from the organic solvent, by conventional methods. Ammonia borane having a purity of 99 weight % or greater may be obtained.
- Figure 1 is a chart of the solubility of ammonia borane and sodium ammonium carbonate versus the concentration of sodium hydroxide in solution, at 25 °C.
- the crude ammonia borane that is purified according to the method of the present invention may be obtained from a variety of sources.
- a metal borohydride may be reacted with an ammonia salt in an organic ether, such a tetrahydrofuran (“THF”) or dioxane.
- THF tetrahydrofuran
- Processes for synthesizing ammonia borane are disclosed in the following references:
- the metal borohydride may be selected from lithium borohydride and sodium borohydride
- the ammonia salt may be selected from ammonium sulfate, ammonium chloride, ammonium fluoride, ammonium carbonate, ammonium nitrate, ammonium acetate, or ammonium formate.
- the reaction is conducted in an organic solvent in which ammonia borane is soluble, such as an organic ether.
- Suitable organic ethers include THF, 2- methyltetrahydrofuran, diethylether and dioxane.
- the crude ammonia borane may be in the form of a solution in an organic solvent, such as an organic ether.
- an organic solvent such as an organic ether.
- the mixture may be filtered to remove insoluble by-products.
- the crude ammonia borane remains dissolved in the organic solvent in which the synthesis was conducted. Thus, it is not necessary to isolate the ammonia borane from the solvent in which it was synthesized, prior to practicing the purification process of the present invention.
- the crude ammonia borane may be in the form of isolated solids.
- the mixture is filtered to remove insoluble by-products, followed by evaporation of the organic solvent from the filtrate, for example, by stripping the solvent under vacuum. After the solvent is removed, crude ammonia borane in solid form is recovered.
- the crude ammonia borane may be dissolved in an organic solvent, to practice the present purification process.
- the crude ammonia borane may be in the form of a suspension or slurry in an organic liquor.
- an organic liquor is added to the vessel.
- the organic liquor has the properties of being water immiscible and the ammonia borane is insoluble therein.
- the organic liquor is selected to have a boiling point higher than the organic ether solvent and facilitates stripping the remaining organic ether solvent from the liquor. Then, any remaining organic ether solvent is removed from the vessel, and the crude ammonia precipitates as a suspension or slurry in the organic liquid.
- suitable organic liquors include pentane, hexane and heptane, in particular, the straight chain (n-) isomers thereof.
- the crude ammonia borane can then be dissolved in an organic solvent, to practice the present purification process. It also within the scope of the present invention for the organic liquor to be present, when the crude ammonia borane solution is mixed with the basic aqueous solvent.
- Crude ammonia borane for example, ammonia borane having a purity of less than 99%, may be purified according to the following methods.
- the crude ammonia borane may be obtained from the above described methods of synthesis and dissolved in an organic solvent.
- the impurities in the crude ammonia borane may be insoluble, partially soluble, soluble, immiscible, partially miscible, or miscible in the crude ammonia borane solution.
- the crude ammonia borane solution is mixed with a basic aqueous solvent.
- the basic aqueous solvent and the organic solvent form a two-phase system, although minor amounts, for example 10% by weight or less, of the organic solvent may be soluble in the basic aqueous solvent, especially when the system is heated.
- the pH of the basic aqueous solution that is mixed with the crude ammonia borane solution is from 8 to 14, in particular, from 8 to 13.
- Suitable basic aqueous solvents include solutions of inorganic hydroxides, such as alkali metal hydroxides and alkaline earth metal hydroxides, including sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide and calcium hydroxide.
- the crude ammonia borane solution and the basic aqueous solution are mixed at conditions under which the byproducts, and such other impurities as may be present in the organic solvent, are separated by partitioning into the basic aqueous solvent, precipitating from or evolving from the mixture.
- the pH of the basic aqueous solvent for example the
- concentration of the hydroxide, the volume of the basic aqueous solvent and the temperature at which the mixing and separation step is conducted are selected to increase the solubility of the impurities in the basic aqueous solvent, especially the metal ammonium salts, and decrease the solubility of ammonia borane in the basic aqueous solution.
- Metal ammonium salts for example sodium ammonium carbonate, are byproducts of the reaction to synthesize ammonia borane from a metal borohydride and an ammonium salt. It has been found that the relative solubility of the metal ammonium salts and ammonia borane in the basic aqueous solvent varies significantly as the concentration of hydroxides varies in the basic aqueous solvent. Referring to Figure 1, the solubility of ammonia borane and the solubility of sodium ammonium carbonate are plotted against the concentration of sodium hydroxide in solution, at 25 °C. At about 5 weight % NaOH in solution, the solubility of ammonia borane and sodium ammonium carbonate are similar.
- An important aspect of the present invention is to remove the impurities present in the crude ammonia borane solution, while minimizing the loss of ammonia borane, for example by ammonia borane partitioning into the basic aqueous phase or decomposing.
- the loss of ammonia borane can be minimized by adjusting the pH of the basic aqueous solution and the temperature of the mixing and separation step to limit the solubility of the ammonia borane in the basic aqueous solution to 200 g/kg or less, 150 g/kg or less, or even 100 g/kg or less, based on ammonia borane in the basic aqueous solvents, as determined without the byproducts and organic solvent present in the system.
- the loss of ammonia borane can also be reduced by limiting the quantity of the basic aqueous solvent mixed with the crude ammonia borane solution to the minimum amount necessary to solubilize the metal ammonium salts.
- the amount of ammonia borane that is soluble in the basic aqueous solvent is decreased, relative to the solubility of ammonia borane in the absence of the metal ammonium salt.
- the volume of the basic aqueous solvent necessary to extract the metal ammonium salt at saturation or near saturation levels can be determined by analyzing the concentration of the metal ammonium salt in the crude ammonium borane solution to be purified.
- the ratio of the volume of the basic aqueous solution to the volume of the crude ammonia borane solution may range from 1 :1 to 1 :10, in particular from 1 :3 to 1 :7, respectively.
- the mixing and separation step may be effectively conducted at temperatures ranging from 20 to 50 °C, in particular from 25 to 45 °C, more particularly from 30 to 40 °C.
- a feature of the present method is that during the mixing step certain of the impurities present in the crude ammonia borane solution are decomposed by or react with the basic aqueous solvent and such reactants can also be extracted by the basic aqueous solvent, evolve as a gas or precipitate. The rate of reaction and/or decomposition of the impurities is promoted by increasing the temperature of the mixing step, although dimim ⁇ hing returns are observed above 50 °C. Additionally, care must be exercised to avoid decomposing the ammonia borane, which becomes unstable in a basic aqueous environment at increased temperatures.
- the mixture of the crude ammonia borane solution and the basic aqueous solvent may be agitated for 10 minutes or more, in particular from 10 to 60 minutes.
- agitation of the mixture is stopped and the mixture is allowed to phase separate.
- the organic solvent phase containing ammonia borane dissolved in the organic solvent is separated from the basic aqueous solvent and precipitates present in the aqueous layer and sediment.
- the organic solvent may be filtered to remove minor amounts of insoluble impurities suspended therein.
- the organic solvent may then be removed from the ammonia borane solution by stripping the solvent under reduced pressure, for example, under vacuum at from 45 to 50 °C. When most of the solvent has been removed, for example 90 to 95%, an organic liquor, in which the ammonia borane is insoluble, is added to the remaining organic solvent and ammonia borane.
- the organic liquor facilitates stripping the remaining organic solvent from the liquor, leaving the purified ammonia borane in suspension in the organic liquor.
- suitable organic liquors include pentane, hexane and heptane, in particular, the straight chain (n-) isomers thereof.
- the ammonia borane suspension is then filtered and the ammonia borane dried.
- Other methods to isolate the ammonia borane recovered in the organic solvent phase of the mixture include spray drying and crystallization of ammonia borane after being concentrated in the organic solvent.
- the method of the present invention may be conducted as a batch process or a continuous process.
- the mixture was digested for 4 hours. Following the 4 hour digest, the pot was cooled to 25-30°C. At this time, the resulting crude ammonia borane solution, including dissolved and un-dissolved byproducts (primarily sodium ammonium carbonate) was mixed with an 18.5% NaOH aqueous caustic solution (220-230gm). The pot was allowed to warm to 30-35 during the addition. Once the caustic was in the pot, the agitation was slowed for 10 minutes and then stopped to allow the bottom aqueous layer to settle out. The bottom layer (260-270gm) was removed and the top layer was filtered at 25-35°C to remove small amounts of insoluble.
- the high-purity ammonia borane made according to the present invention has application as a storage medium for hydrogen in vehicles containing fuel cells, as well as for any other applications where reagent grade ammonia borane may be advantageously employed.
- Examples of applications for ammonia borane may be found in the following references: Mohajeri et al. US 2008/0159949 Al; Hsueh et al. 2010/0230636 Al; Chen et al. US 2010/0329974 Al; Abdur- Rashid et al. US 2011/0104046 Al; Chen et al. US 2011/0158881 Al; and Balema et al. WO 2011/02303.
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Abstract
A method of purifying ammonia borane is provided in which crude ammonia borane is dissolved in an organic solvent, such as an ether, and mixed with a basic aqueous solution to form a two-phase system. The pH of the aqueous solution and the temperature are adjusted to increase the solubility of the impurities and decrease the solubility of the ammonia borane in the basic aqueous solution, without causing decomposition of the ammonia borane. The impurities are separated from the crude ammonia borane solution, the mixture is phase-separated and the dissolved ammonia borane is isolated from the organic solvent fraction. High purity ammonia borane is obtained.
Description
AMMONIA BORANE PURIFICATION METHOD
This invention is directed to a method of purifying ammonia borane, which includes the steps of forming a mixture of (a) a solution of crude ammonia borane in an organic solvent and (b) a basic aqueous solution, at conditions under which impurities present in the crude ammonia borane, such as sodium ammonium carbonate, are substantially more soluble in the aqueous solution than is the ammonia borane. After the impurities are extracted or caused to precipitate from the organic solvent, the organic solvent containing ammonia borane is phase separated from the basic aqueous solution. Ammonia borane having a purity of 99% or greater can be recovered from the organic solvent layer.
Background of the Invention
Ammonia borane, also referred to as ammonium borane and borazane, has been investigated as an energy-dense source of hydrogen, for example, for use in hydrogen related power generation. Methods of synthesis of ammonia borane are disclosed in amachandran et al. US 2007/0243122 Al ("Ramachandran"). Briefly, the process involves reacting a metal borohydride with an ammonia salt, in a suitable solvent. For example, sodium borohydride is reacted with ammonium carbonate in an ether solvent, such as tetrahydrofuran ("THF") or dioxane. Following the reaction to form ammonia borane, the solution is filtered and the solvent is removed under vacuum to yield solid ammonia borane. The recovered ammonia borane powder may be purified by extraction with a suitable solvent, followed by removal of the solvent under reduced pressure, to yield a solid ammonia borane of relatively high purity.
A shortcoming of prior art ammonia borane purification methods is that many of the impurities present in the crude ammonia borane are also soluble in the solvent used to extract the ammonia borane. Consequently, when the solvent is evaporated from the ammonia borane solution, such impurities remain in the recovered product. Thus, despite the methods disclosed by Ramachandran and others, a need remains for an ammonia borane purification method that is economical to operate commercially and yields high-purity ammonia borane.
It can be understood that metal ammonium salts, such as sodium ammonium carbonate, are a significant byproduct of the synthesis reaction between a metal borohydride and an
ammonia salt. Isolating ammonia borane from metal ammonium salts and other byproducts of the reaction has proven difficult in the past, due to the difficulty of filtering byproducts that have precipitated in the reaction slurry and due to the similar solubilities of ammonia borane and the byproducts in a range of polar and non-polar solvents. The utility of ammonia borane as a hydrogen storage medium is linked to its ability to release H2 over a wide range conditions, including in the presence of ionic liquids and bases. Accordingly, purification of crude ammonia borane is limited to conditions that do not trigger decomposition of the ammonia borane and ¾ release.
Summary of the Invention
An object of the invention is to provide high-purity ammonia borane, for example, ammonia borane having a purity of 99% or higher, by weight. Another object of the invention is to provide an ammonia borane purification method, whereby crude ammonia borane is treated to remove impurities, while the ammonia borane is dissolved in an organic solvent. Yet another object of the invention is provide a purification method that may be used with a solution of crude ammonia borane in the organic ether in which the ammonia borane is synthesized. Still another object of the invention is to employ a basic aqueous solution to extract, digest and or precipitate impurities present in crude ammonia borane, at conditions under which the solubility of ammonia borane in the aqueous solution is minimal. Another object of the invention is to provide a method of ammonia borane purification that is economical to operate commercially and can be adapted to either a batch or continuous process. The foregoing objectives are met by one or more of the following embodiments of the present invention.
The process may be employed to purify crude ammonia borane produced by any of a variety of synthetic processes. The crude ammonia borane may be in the form of an isolated solid, such as a dry powder or a wet filter cake, or the crude ammonia borane may be suspended in a suitable organic liquor. Ammonia borane can be synthesized in an organic ether, with the resulting crude ammonia borane dissolved therein. The crude ammonia borane solution can be advantageously used directly in the present purification process, without the need to first isolate the ammonia borane from the organic solvent. Regardless of the synthetic method used to produce the crude ammonia borane or its physical state, the crude ammonia borane can be dissolved in a suitable organic solvent and purified according to the method herein.
The purification process is conducted with the crude ammonia borane dissolved in an organic solvent, such as an organic ether, referred to herein as the crude ammonia borane solution. The solution contains impurities, including byproducts from the synthesis of ammonia borane. The byproducts are typically metal ammonium salts, produced by the reaction of a metal borohydride and an ammonia salt in an organic ether, such as sodium ammonium carbonate, as well as unreacted starting material, dimers, trimers, and other self-condensation products, and other borates. The impurities exhibit a wide range of solubilities in the organic solvent, that is, a particular impurity may be insoluble, partially soluble or soluble in the organic solvent.
The crude ammonia borane solution is mixed with a basic aqueous solution, to form a two-phase system. The basic aqueous solution may be an alkali metal hydroxide or an alkaline earth metal hydroxide. The pH may range from 8 to 14.
The crude ammonia borane solution and the basic aqueous solution are mixed at conditions under which the impurities present in the organic solvent are separated by partitioning into the basic aqueous solvent or precipitating from the mixture. Another feature of the process is that some of the impurities can be decomposed by or react with the basic aqueous solvent and such reactants can also be extracted by the basic aqueous solvent, evolve as a gas or precipitate. Thus, the step of separating the impurities from the organic solvent is intended to include the impurities present in the crude ammonia borane solution, as well as any decomposition products or reactants derived from the impurities that are extracted into the basic aqueous solution, precipitated from or evolved from the mixture.
The pH of the basic aqueous solvent, for example the concentration of the hydroxide, the volume of the basic aqueous solvent and the temperature at which the mixing and separation step is conducted are selected to increase the solubility of the impurities in the basic aqueous solvent, especially the metal ammonium salts, and decrease the solubility of ammonia borane in the basic aqueous solution. By following the teachings herein, it is possible to separate the metal ammonium salts present in the crude ammonia borane solution at conditions under which the metal ammonium salts are at least two times, four times or even eight times more soluble in the basic aqueous solvent than the ammonia borane is soluble in the basic aqueous solution during the mixing step.
The mixing and separation step may be effectively conducted at temperatures ranging from 20 to 50 °C. By way of example, the objectives of the invention have been achieved when the mixing and separation step is conducted for 10 minutes or more.
In the next steps of the process, the mixture is allowed to phase separate and the organic solvent phase containing dissolved ammonia borane is separated from the basic aqueous solvent and precipitates. The ammonia borane may then be isolated from the organic solvent, by conventional methods. Ammonia borane having a purity of 99 weight % or greater may be obtained.
Brief Description of the Drawings
Figure 1 is a chart of the solubility of ammonia borane and sodium ammonium carbonate versus the concentration of sodium hydroxide in solution, at 25 °C.
Detailed Description of the Invention
Without limiting the scope of the invention, the preferred embodiments and features are hereinafter set forth. All of the United States patents and published applications, which are cited in the specification, are hereby incorporated by reference. Unless otherwise indicated, conditions are 25 °C, 1 atmosphere of pressure and 50% relative humidity and concentrations are by weight. Unless otherwise indicated, the relative solubilities of byproducts, such as the metal ammonium salts, and ammonia borane in the basic aqueous solvent are determined separately, that is, the solubility of each in the basic aqueous solvent is measured without the presence of the other. Unless otherwise indicated, the solubility in the basic aqueous solvent reported for the byproducts or ammonia borane is determined separately.
Synthesis of Crude Ammonia Borane
The crude ammonia borane that is purified according to the method of the present invention may be obtained from a variety of sources. For example, a metal borohydride may be reacted with an ammonia salt in an organic ether, such a tetrahydrofuran ("THF") or dioxane. Processes for synthesizing ammonia borane are disclosed in the following references:
Ramachandran et al. US 2007/0243122 Al; Autrey et al. US 7,897,129 B2; Yang et al. US 8,038,980 B2; Shore et al. US 2009/0104102 Al; Lukacs et al. US 2010/0272623 Al; Kaye et al. US 2011/0064640 Al; and Kikukawa Yasuo JP 2012-001419 A.
By way of example, the metal borohydride may be selected from lithium borohydride and sodium borohydride, and the ammonia salt may be selected from ammonium sulfate, ammonium chloride, ammonium fluoride, ammonium carbonate, ammonium nitrate, ammonium acetate, or ammonium formate. The reaction is conducted in an organic solvent in which ammonia borane is soluble, such as an organic ether. Suitable organic ethers include THF, 2- methyltetrahydrofuran, diethylether and dioxane. In one process for synthesizing ammonia borane, sodium borohydride and ammonium carbonate react in THF to form ammonia borane.
The synthesis reaction is represented by the equation below:
THF
NaBH4 + (NH4)2C03 5g_65oC *~ NH3BH3 + NaNH4C03 + H2
The crude ammonia borane may be in the form of a solution in an organic solvent, such as an organic ether. For example, after the synthesis reaction is complete, the mixture may be filtered to remove insoluble by-products. The crude ammonia borane remains dissolved in the organic solvent in which the synthesis was conducted. Thus, it is not necessary to isolate the ammonia borane from the solvent in which it was synthesized, prior to practicing the purification process of the present invention.
The crude ammonia borane may be in the form of isolated solids. For example, after the synthesis reaction is complete, the mixture is filtered to remove insoluble by-products, followed by evaporation of the organic solvent from the filtrate, for example, by stripping the solvent under vacuum. After the solvent is removed, crude ammonia borane in solid form is recovered. The crude ammonia borane may be dissolved in an organic solvent, to practice the present purification process.
The crude ammonia borane may be in the form of a suspension or slurry in an organic liquor. For example, after the synthesis of ammonia borane in the presence of an organic ether, most of the organic ether is stripped off and an organic liquor is added to the vessel. The organic liquor has the properties of being water immiscible and the ammonia borane is insoluble therein. Furthermore, the organic liquor is selected to have a boiling point higher than the organic ether solvent and facilitates stripping the remaining organic ether solvent from the liquor. Then, any remaining organic ether solvent is removed from the vessel, and the crude ammonia precipitates
as a suspension or slurry in the organic liquid. Examples of suitable organic liquors include pentane, hexane and heptane, in particular, the straight chain (n-) isomers thereof. The crude ammonia borane can then be dissolved in an organic solvent, to practice the present purification process. It also within the scope of the present invention for the organic liquor to be present, when the crude ammonia borane solution is mixed with the basic aqueous solvent.
Purification of Crude Ammonia Borane
Crude ammonia borane, for example, ammonia borane having a purity of less than 99%, may be purified according to the following methods. The crude ammonia borane may be obtained from the above described methods of synthesis and dissolved in an organic solvent. The impurities in the crude ammonia borane may be insoluble, partially soluble, soluble, immiscible, partially miscible, or miscible in the crude ammonia borane solution.
The crude ammonia borane solution is mixed with a basic aqueous solvent. The basic aqueous solvent and the organic solvent form a two-phase system, although minor amounts, for example 10% by weight or less, of the organic solvent may be soluble in the basic aqueous solvent, especially when the system is heated. By way of example, the pH of the basic aqueous solution that is mixed with the crude ammonia borane solution is from 8 to 14, in particular, from 8 to 13. Suitable basic aqueous solvents include solutions of inorganic hydroxides, such as alkali metal hydroxides and alkaline earth metal hydroxides, including sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide and calcium hydroxide.
The crude ammonia borane solution and the basic aqueous solution are mixed at conditions under which the byproducts, and such other impurities as may be present in the organic solvent, are separated by partitioning into the basic aqueous solvent, precipitating from or evolving from the mixture. The pH of the basic aqueous solvent, for example the
concentration of the hydroxide, the volume of the basic aqueous solvent and the temperature at which the mixing and separation step is conducted are selected to increase the solubility of the impurities in the basic aqueous solvent, especially the metal ammonium salts, and decrease the solubility of ammonia borane in the basic aqueous solution.
Metal ammonium salts, for example sodium ammonium carbonate, are byproducts of the reaction to synthesize ammonia borane from a metal borohydride and an ammonium salt. It has
been found that the relative solubility of the metal ammonium salts and ammonia borane in the basic aqueous solvent varies significantly as the concentration of hydroxides varies in the basic aqueous solvent. Referring to Figure 1, the solubility of ammonia borane and the solubility of sodium ammonium carbonate are plotted against the concentration of sodium hydroxide in solution, at 25 °C. At about 5 weight % NaOH in solution, the solubility of ammonia borane and sodium ammonium carbonate are similar. As the concentration of NaOH increases, however, the solubility of ammonia borane decreases and the solubility of sodium ammonium carbonate increases dramatically. By way of example, an aqueous solution of 15 to 20 weight % of sodium hydroxide has been shown to provide a significant difference between the solubility of ammonia borane and the metal ammonium salt byproduct.
It can be understood that by adjusting the pH of the basic aqueous liquor, for example, by varying the concentration of the inorganic hydroxide, it is possible to extract the metal borohydride salt byproducts present in the crude ammonia borane solution at conditions under which the byproducts are at least two times, four times or even eight times more soluble in the basic aqueous solvent than the ammonia borane is soluble in the basic aqueous solution.
An important aspect of the present invention is to remove the impurities present in the crude ammonia borane solution, while minimizing the loss of ammonia borane, for example by ammonia borane partitioning into the basic aqueous phase or decomposing. The loss of ammonia borane can be minimized by adjusting the pH of the basic aqueous solution and the temperature of the mixing and separation step to limit the solubility of the ammonia borane in the basic aqueous solution to 200 g/kg or less, 150 g/kg or less, or even 100 g/kg or less, based on ammonia borane in the basic aqueous solvents, as determined without the byproducts and organic solvent present in the system.
The loss of ammonia borane can also be reduced by limiting the quantity of the basic aqueous solvent mixed with the crude ammonia borane solution to the minimum amount necessary to solubilize the metal ammonium salts. By operating at conditions whereby the basic aqueous solvent is saturated or near saturated, for example, at least 75% saturated or even at least 90% saturated, with the metal ammonium salt, the amount of ammonia borane that is soluble in the basic aqueous solvent is decreased, relative to the solubility of ammonia borane in the absence of the metal ammonium salt. The volume of the basic aqueous solvent necessary to
extract the metal ammonium salt at saturation or near saturation levels can be determined by analyzing the concentration of the metal ammonium salt in the crude ammonium borane solution to be purified. By way of example, the ratio of the volume of the basic aqueous solution to the volume of the crude ammonia borane solution may range from 1 :1 to 1 :10, in particular from 1 :3 to 1 :7, respectively.
The mixing and separation step may be effectively conducted at temperatures ranging from 20 to 50 °C, in particular from 25 to 45 °C, more particularly from 30 to 40 °C. A feature of the present method is that during the mixing step certain of the impurities present in the crude ammonia borane solution are decomposed by or react with the basic aqueous solvent and such reactants can also be extracted by the basic aqueous solvent, evolve as a gas or precipitate. The rate of reaction and/or decomposition of the impurities is promoted by increasing the temperature of the mixing step, although dimim^hing returns are observed above 50 °C. Additionally, care must be exercised to avoid decomposing the ammonia borane, which becomes unstable in a basic aqueous environment at increased temperatures. During the mixing and separating step, the mixture of the crude ammonia borane solution and the basic aqueous solvent may be agitated for 10 minutes or more, in particular from 10 to 60 minutes.
In the next steps of the process, agitation of the mixture is stopped and the mixture is allowed to phase separate. The organic solvent phase containing ammonia borane dissolved in the organic solvent is separated from the basic aqueous solvent and precipitates present in the aqueous layer and sediment. The organic solvent may be filtered to remove minor amounts of insoluble impurities suspended therein. The organic solvent may then be removed from the ammonia borane solution by stripping the solvent under reduced pressure, for example, under vacuum at from 45 to 50 °C. When most of the solvent has been removed, for example 90 to 95%, an organic liquor, in which the ammonia borane is insoluble, is added to the remaining organic solvent and ammonia borane. The organic liquor facilitates stripping the remaining organic solvent from the liquor, leaving the purified ammonia borane in suspension in the organic liquor. Examples of suitable organic liquors include pentane, hexane and heptane, in particular, the straight chain (n-) isomers thereof. The ammonia borane suspension is then filtered and the ammonia borane dried. Other methods to isolate the ammonia borane recovered
in the organic solvent phase of the mixture include spray drying and crystallization of ammonia borane after being concentrated in the organic solvent.
The method of the present invention may be conducted as a batch process or a continuous process.
By following the teaching herein, it is possible to remove at least 50 weight %, at least 75 weight % or even at least 90 weight % of the byproducts from the crude ammonia borane solution. Ammonia borane having a purity of 99 weight % or greater may be obtained.
Example 1 - Synthesis of Crude Ammonia Borane and Purification
1000 g of virgin THF (Kf < 0.1%) was charged to a pot and cooled to <10°C. To the pot was then charged sodium borohydride (31.0gm, 0.819mol) and the mixture was warmed to 30-35°C. During heating, the mantle temperature was not allowed to rise above 35°C. Once the pot was in the temperature range, the ammonium carbonate (78gm, 0.81 lmol) was added over a 1 hour period, and off-gassing of hydrogen was observed. Once all of the ammonium carbonate was added, the pot was warmed to 58-60°C over 1 hour. A flow of nitrogen was used during the reaction, to dilute the hydrogen that evolved. Once the pot temperature reached 58-60°C, the mixture was digested for 4 hours. Following the 4 hour digest, the pot was cooled to 25-30°C. At this time, the resulting crude ammonia borane solution, including dissolved and un-dissolved byproducts (primarily sodium ammonium carbonate) was mixed with an 18.5% NaOH aqueous caustic solution (220-230gm). The pot was allowed to warm to 30-35 during the addition. Once the caustic was in the pot, the agitation was slowed for 10 minutes and then stopped to allow the bottom aqueous layer to settle out. The bottom layer (260-270gm) was removed and the top layer was filtered at 25-35°C to remove small amounts of insoluble. The resulting clear solution was stripped at 45-50°C with vacuum. The strip was continued until 90-95% of organic weight was removed (850-950gm). At this point, the vacuum was broken with nitrogen and to the pot was added heptane (150-200gm). The pot was restriped to remove the remainder of the THF. Once the remainder of the THF was removed, the pot was cooled to room temperature and the desire product was filtered. The resulting wet cake was dried at room temperature with vacuum to yield a white solid (17-18 grams). The yield was 68-72%. NMR analysis of this product showed > 99.2% purity.
Applications of Ammonia Borane
The high-purity ammonia borane made according to the present invention has application as a storage medium for hydrogen in vehicles containing fuel cells, as well as for any other applications where reagent grade ammonia borane may be advantageously employed. Examples of applications for ammonia borane may be found in the following references: Mohajeri et al. US 2008/0159949 Al; Hsueh et al. 2010/0230636 Al; Chen et al. US 2010/0329974 Al; Abdur- Rashid et al. US 2011/0104046 Al; Chen et al. US 2011/0158881 Al; and Balema et al. WO 2011/02303.
The invention may be further understood by reference to the following claims.
Claims
1. A method of purifying crude ammonia borane, comprising the steps of:
(a) providing a crude ammonia borane solution, comprising ammonia borane dissolved in an organic solvent and impurities comprising byproducts generated from the synthesis of the ammonia borane;
(b) providing a basic aqueous solution;
(c) mixing the crude ammonia borane solution and the basic aqueous solution, wherein the organic solvent and the basic aqueous solution form a two-phase system, and wherein the mixing is conducted at conditions under which at least some of the impurities are separated from the organic solvent by partitioning into the basic aqueous solution, degrading or precipitating;
(d) allowing the phases to partition into an organic solvent phase containing ammonia borane dissolved therein and a basic aqueous solution phase;
(e) separating the organic solvent phase from the basic aqueous solution phase; and
(f) isolating the ammonia borane in the organic solvent phase from the organic solvent.
2. The method of Claim 1 , wherein the basic aqueous solution has a pH of from 8 to 13.5.
3. The method of Claim 2, wherein the basic aqueous solution comprises an inorganic
hydroxide selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides.
4. The method of Claim 3, wherein the organic solvent is an ether and the byproducts
comprise sodium ammonium carbonate, and the solubility of sodium ammonium carbonate in the basic aqueous solution is at least four times greater than the solubility of ammonia borane in the basic aqueous solution at 25 °C.
5. The method of Claim 4, wherein the mixing step is conducted at a temperature of from 20 to 50 °C for at least 10 minutes, and at least 50 weight % of the impurities are separated from the crude ammonia borane solution.
6. The method of Claim 1, wherein the byproducts comprise metal ammonium salt, and the solubility of the metal ammonium salt in the basic aqueous solution is at least two times greater than the solubility of ammonia borane in the basic aqueous solution at 25 °C.
7. The method of Claim 1, wherein the byproducts comprise a metal ammonium salt, and the solubility of the metal ammonium salt in the basic aqueous solution is at least four times greater than the solubility of ammonia borane in the basic aqueous solution at 25 °C.
8. The method of Claim 1, wherein the byproducts comprise a metal ammonium salt, and the solubility of the metal ammonium salt in the basic aqueous solution is at least eight times greater than the solubility of ammonia borane in the basic aqueous solution at 25 °C.
9. The method of Claim 8, wherein the basic aqueous solution comprises a concentration of from 15 to 20 weight % of sodium hydroxide.
10. The method of Claim 8, wherein organic solvent is an ether and the solubility of
ammonia borane in the basic aqueous solution is 200 g per kg or less at 25 °C.
11. A method of purifying crude ammonia borane, comprising the steps of:
(a) providing a crude ammonia borane solution, comprising ammonia borane dissolved in an organic solvent and byproducts, wherein the byproducts are generated from the synthesis of ammonia borane by the reaction of a metal borohydride and an ammonia salt in an organic ether;
(b) providing a basic aqueous solution;
(c) mixing the crude ammonia borane solution and the basic aqueous solution, wherein the organic solvent and the basic aqueous solution form a two-phase system, and wherein the mixing is conducted at conditions under which at least 50 weight % of the byproducts are separated from the organic solvent by partitioning into the basic aqueous solution, degrading or precipitating;
(d) allowing the phases to partition into an organic solvent phase containing ammonia borane dissolved therein and a basic aqueous solution phase;
(e) separating the organic solvent phase from the basic aqueous solution phase; and
(f) isolating the ammonia borane in the organic solvent phase from the organic solvent.
12. The method of Claim 11, wherein the basic aqueous solution comprises an inorganic hydroxide selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides.
13. The method of Claim 12, wherein the organic solvent is an ether selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, diethylether and dioxane.
14. The method of Claim 11, wherein the byproducts comprise a metal ammonium salt and wherein the mixing step is conducted at conditions under which the solubility of the metal ammonium salt in the basic aqueous solution is at least four times greater than the solubility of ammonia borane in the basic aqueous solution.
15. The method of Claim 14, wherein the solubility of ammonia borane in the basic aqueous solution is 150 g kg or less at 25 °C.
16. A method of purifying crude ammonia borane, comprising the steps of:
(a) providing a crude ammonia borane solution, comprising ammonia borane dissolved in an organic ether and byproducts, wherein the byproducts comprise metal ammonium salts generated from the synthesis of ammonia borane;
(b) providing a basic aqueous solution;
(c) mixing the crude ammonia borane solution and the basic aqueous solution, wherein the organic ether and the basic aqueous solution form a two-phase system, and wherein the mixing is conducted at conditions under which at least 50 weight % of the metal ammonium salts are separated from the organic ether by partitioning into the basic aqueous solution;
(d) allowing the phases to partition into an organic ether phase containing ammonia borane dissolved therein and a basic aqueous solution phase;
(e) separating the organic ether phase from the basic aqueous solution phase; and
(f) isolating the ammonia borane in the organic ether phase from the organic ether, wherein the ammonia borane has a purity of 99 weight % or greater.
17. The method of Claim 16, wherein the basic aqueous solution comprises an inorganic hydroxide selected from sodium hydroxide and potassium hydroxide, and wherein the organic ether is selected from the group consisting of tetrahydrofuran, 2- methyltetrahydrofuran, diethylether and dioxane.
18. The method of Claim 16, wherein the metal ammonium hydroxide is sodium ammonium carbonate, and wherein the mixing step is conducted at conditions under which the solubility of the sodium ammonium carbonate in the basic aqueous solution is at least four times greater than the solubility of ammonia borane in the basic aqueous solution.
19. The method of Claim 16, wherein the solubility of ammonia borane in the basic aqueous solution is 150 g per kg or less at 25 °C, and the solubility of the metal ammonium salt in the basic aqueous solution is at least eight times greater than the solubility of ammonia borane in the basic aqueous solution at 25 °C.
20. The method of Claim 19, wherein the basic aqueous solution comprises a concentration of from 15 to 20 weight % of sodium hydroxide.
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Citations (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6060623A (en) * | 1999-01-08 | 2000-05-09 | Shiroi Yakuhin Co., Ltd. | Process for producing amine borane compound |
US20070128475A1 (en) | 2005-11-04 | 2007-06-07 | Blacquiere Johanna M | Base metal dehydrogenation of amine-boranes |
US20070243122A1 (en) | 2006-03-13 | 2007-10-18 | Ramachandran P V | Process for the synthesis and methanolysis of ammonia borane and borazine |
US20080159949A1 (en) | 2006-04-28 | 2008-07-03 | Nahid Mohajeri | Catalytic dehydrogenation of amine borane complexes |
US20090104102A1 (en) | 2006-04-03 | 2009-04-23 | Sheldon Gerald Shore | Methods for synthesizing ammonia borane |
US20100230636A1 (en) | 2009-03-13 | 2010-09-16 | Industrial Technology Research Institute | Solid-state hydrogen fuel with polymer matrix and fabrication methods thereof |
US20100272623A1 (en) | 2009-04-22 | 2010-10-28 | K-Energetics Corp. | Ambient temperature liquid ammonia process for the manufacture of ammonia borane |
US20100329974A1 (en) | 2007-12-05 | 2010-12-30 | National University Of Singapore | hydrogen storage material and a process for release of hydrogen |
WO2011002303A1 (en) | 2009-07-02 | 2011-01-06 | Uno Andersen | A device for the production of biogas from organic waste |
US7897129B2 (en) | 2008-05-22 | 2011-03-01 | Battelle Memorial Institute | Process for synthesis of ammonia borane for bulk hydrogen storage |
US20110064640A1 (en) | 2009-09-16 | 2011-03-17 | Wildcat Discovery Technologies | Method of preparing boron-nitrogen compounds |
US20110104046A1 (en) | 2008-05-16 | 2011-05-05 | Kamaluddin Abdur-Rashid | Method for the production of hydrogen from the dehydrocoupling of amine boranes |
US20110158881A1 (en) | 2009-12-30 | 2011-06-30 | Dalian Institute Of Chemical Physics, Chinese Academy Of Sciences | Method of synthesizing crystalline polymeric boron-nitrogen compound and dehydrogenation of boron-nitrogen-hydrogen complex |
US8038980B2 (en) | 2009-07-08 | 2011-10-18 | Ford Motor Company | Hydrogen storage materials containing ammonia borane |
JP2012001419A (en) | 2010-06-21 | 2012-01-05 | Yasuo Kikukawa | Method for producing ammonia borane |
US20130121905A1 (en) | 2010-05-21 | 2013-05-16 | Herakles | Method for obtaining borazane, suitable for obtaining highly pure and very highly pure borazane |
US20130225863A1 (en) * | 2010-07-09 | 2013-08-29 | Purdue Research Foundation | Procedures for the Synthesis of Ethylenediamine Bisborane and Ammonia Borane |
US20140186252A1 (en) * | 2012-12-28 | 2014-07-03 | Weylchem Sustainable Materials, Llc | Ammonia borane purification method |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3313603A (en) | 1964-05-29 | 1967-04-11 | Callery Chemical Co | Borane compounds and their preparation |
US3882037A (en) | 1973-02-22 | 1975-05-06 | Aldrich Boranes Inc | Stabilized borane-tetrahydrofuran solutions |
US4801439A (en) | 1986-09-15 | 1989-01-31 | Sri International | Catalytic process for making compounds having a non-Lewis acid/base bond between a group IIIA metal and group VA nonmetal |
DE4441064C1 (en) | 1994-11-18 | 1996-07-18 | Metallgesellschaft Ag | Process for the preparation of alkali aminoborohydrides and alkali aminoborohydride complexes and their use |
US6586563B1 (en) | 2001-12-18 | 2003-07-01 | Millennium Cell, Inc. | Processes for synthesizing alkali metal borohydride compounds |
US20080175781A1 (en) | 2006-09-22 | 2008-07-24 | The Regents Of The University Of California | Bootstrap synthesis of boranes |
US7695704B2 (en) | 2007-02-13 | 2010-04-13 | Gm Global Technology Operations, Inc. | Procedure for the hydrogenation of BNH-containing compounds |
US8920760B2 (en) | 2009-08-27 | 2014-12-30 | Sigma-Aldrich Co. Llc | Metal amidoborane compositions and processes for their preparation |
-
2014
- 2014-12-19 EP EP14873510.3A patent/EP3087029A4/en not_active Withdrawn
- 2014-12-19 US US14/576,296 patent/US9604850B2/en not_active Expired - Fee Related
- 2014-12-19 CA CA2937768A patent/CA2937768C/en not_active Expired - Fee Related
- 2014-12-19 WO PCT/US2014/071426 patent/WO2015100157A1/en active Application Filing
Patent Citations (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6060623A (en) * | 1999-01-08 | 2000-05-09 | Shiroi Yakuhin Co., Ltd. | Process for producing amine borane compound |
US20070128475A1 (en) | 2005-11-04 | 2007-06-07 | Blacquiere Johanna M | Base metal dehydrogenation of amine-boranes |
US20070243122A1 (en) | 2006-03-13 | 2007-10-18 | Ramachandran P V | Process for the synthesis and methanolysis of ammonia borane and borazine |
US20090104102A1 (en) | 2006-04-03 | 2009-04-23 | Sheldon Gerald Shore | Methods for synthesizing ammonia borane |
US20080159949A1 (en) | 2006-04-28 | 2008-07-03 | Nahid Mohajeri | Catalytic dehydrogenation of amine borane complexes |
US20100329974A1 (en) | 2007-12-05 | 2010-12-30 | National University Of Singapore | hydrogen storage material and a process for release of hydrogen |
US20110104046A1 (en) | 2008-05-16 | 2011-05-05 | Kamaluddin Abdur-Rashid | Method for the production of hydrogen from the dehydrocoupling of amine boranes |
US7897129B2 (en) | 2008-05-22 | 2011-03-01 | Battelle Memorial Institute | Process for synthesis of ammonia borane for bulk hydrogen storage |
US20100230636A1 (en) | 2009-03-13 | 2010-09-16 | Industrial Technology Research Institute | Solid-state hydrogen fuel with polymer matrix and fabrication methods thereof |
US20100272623A1 (en) | 2009-04-22 | 2010-10-28 | K-Energetics Corp. | Ambient temperature liquid ammonia process for the manufacture of ammonia borane |
WO2011002303A1 (en) | 2009-07-02 | 2011-01-06 | Uno Andersen | A device for the production of biogas from organic waste |
US8038980B2 (en) | 2009-07-08 | 2011-10-18 | Ford Motor Company | Hydrogen storage materials containing ammonia borane |
US20110064640A1 (en) | 2009-09-16 | 2011-03-17 | Wildcat Discovery Technologies | Method of preparing boron-nitrogen compounds |
US20110158881A1 (en) | 2009-12-30 | 2011-06-30 | Dalian Institute Of Chemical Physics, Chinese Academy Of Sciences | Method of synthesizing crystalline polymeric boron-nitrogen compound and dehydrogenation of boron-nitrogen-hydrogen complex |
US20130121905A1 (en) | 2010-05-21 | 2013-05-16 | Herakles | Method for obtaining borazane, suitable for obtaining highly pure and very highly pure borazane |
JP2012001419A (en) | 2010-06-21 | 2012-01-05 | Yasuo Kikukawa | Method for producing ammonia borane |
US20130225863A1 (en) * | 2010-07-09 | 2013-08-29 | Purdue Research Foundation | Procedures for the Synthesis of Ethylenediamine Bisborane and Ammonia Borane |
US20140186252A1 (en) * | 2012-12-28 | 2014-07-03 | Weylchem Sustainable Materials, Llc | Ammonia borane purification method |
Non-Patent Citations (1)
Title |
---|
MOURY ET AL.: "Hydrazine Borane: synthesis, characterization and applications;", PHYS. CHEM. CHEM. PHYS., vol. 14, no. 5, 1 January 2011 (2011-01-01), pages 1768 - 1777, XP055354265, DOI: 10.1039/C2CP23403C * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017046539A1 (en) * | 2015-09-18 | 2017-03-23 | Airbus Safran Launchers Sas | Method for purifying borazane |
FR3041337A1 (en) * | 2015-09-18 | 2017-03-24 | Herakles | PROCESS FOR PURIFYING BORAZANE |
US10144649B2 (en) | 2015-09-18 | 2018-12-04 | Arianegroup Sas | Method for purifying borazane |
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CA2937768C (en) | 2017-04-11 |
US9604850B2 (en) | 2017-03-28 |
US20150183646A1 (en) | 2015-07-02 |
EP3087029A1 (en) | 2016-11-02 |
EP3087029A4 (en) | 2017-06-21 |
CA2937768A1 (en) | 2015-07-02 |
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