阅读说明：本技术 双(氟磺酰基)亚胺的纯化 (Purification of bis (fluorosulfonyl) imide ) 是由 马修·H·卢利 伯纳德·E·庞德纳 于 2020-04-14 设计创作，主要内容包括：本发明提供了一种产生纯化的双(氟磺酰基)亚胺的方法,该方法包括提供包含双(氟磺酰基)亚胺和氟磺酸的液体混合物,并且然后使该液体混合物与气态氨接触。气态氨与氟磺酸反应以产生氟硫酸铵。该方法还包括将液体混合物与氟硫酸铵分离。(The present invention provides a method of producing purified bis (fluorosulfonyl) imide, the method comprising providing a liquid mixture comprising bis (fluorosulfonyl) imide and fluorosulfonic acid, and then contacting the liquid mixture with gaseous ammonia. The gaseous ammonia reacts with the fluorosulfonic acid to produce ammonium fluorosulfonate. The method further comprises separating the liquid mixture from the ammonium fluorosulfate.)

1. A method of producing a purified bis (fluorosulfonyl) imide, said method comprising:

providing a liquid mixture comprising bis (fluorosulfonyl) imide and fluorosulfonic acid;

contacting the liquid mixture with gaseous ammonia, wherein the gaseous ammonia reacts with the fluorosulfonic acid to produce ammonium fluorosulfonate; and

separating the liquid mixture from the ammonium fluorosulfate.

2. The method of claim 1, wherein contacting the liquid mixture with gaseous ammonia comprises introducing the gaseous ammonia into a headspace of a vessel containing the liquid mixture.

3. The method of claim 2, wherein the gaseous ammonia is supplied at a pressure between about 100kPa and about 200 kPa.

4. The method of claim 1, wherein contacting the liquid mixture with gaseous ammonia comprises bubbling the gaseous ammonia into the liquid mixture.

5. The method of claim 1, wherein contacting the liquid mixture with gaseous ammonia comprises flowing the gaseous ammonia and the liquid mixture in a reflux column.

6. The method of claim 1, wherein separating the liquid mixture from the ammonium fluorosulfate comprises filtering the ammonium fluorosulfate from the liquid mixture.

7. The method of claim 1, wherein separating the liquid mixture from the ammonium fluorosulfate comprises flashing the bis (fluorosulfonyl) imide from the ammonium fluorosulfate.

8. The method of claim 1, wherein the concentration of the bis (fluorosulfonyl) imide in the liquid mixture is about 90 mol% to about 99.95 mol% after separating the ammonium fluorosulfonate from the liquid mixture.

9. The method of claim 1, further comprising:

providing the liquid mixture after separating the liquid mixture from the ammonium fluorosulfate, the liquid mixture comprising the bis (fluorosulfonyl) imide and residual fluorosulfonic acid;

contacting the liquid mixture with gaseous ammonia, wherein the gaseous ammonia reacts with the residual fluorosulfonic acid in the liquid mixture to produce additional ammonium fluorosulfate; and

separating the liquid mixture from the additional ammonium fluorosulfate.

10. The method of claim 9, wherein the concentration of the bis (fluorosulfonyl) imide in the liquid mixture is about 98 mol% to about 99.95 mol% after separating the additional ammonium fluorosulfate from the liquid mixture.

Technical Field

The present disclosure relates to a method for removing fluorosulfonic acid from a liquid mixture of fluorosulfonic acid and bis (fluorosulfonyl) imide.

Background

Bis (fluorosulfonyl) imide (HFSI) is a key raw material for the production of lithium bis (fluorosulfonyl) imide (LiFSI) for use in lithium ion batteries. HFSI can be prepared by several methods. For example, HFSI can be prepared by the reaction of urea with fluorosulfonic acid, as shown in formula 1:

equation 15 HSO₃F+2CO(NH₂)₂→HN(SO₂F)₂+2CO₂+3NH₄SO₃F。

In another example, HFSI can be prepared by reacting fluorosulfonic acid with fluorosulfonic acid, as shown in equation 2:

equation 2HSO₃F+FSO₂NCO→HN(SO₂F)₂+CO₂。

In the reactions of equations 1 and 2, as well as other reactions to produce HFSI, HFSI is typically contaminated with excess fluorosulfonic acid. HFSI and fluorosulfonic acid boil at 170 ℃ and 165 ℃, respectively, and therefore distillation purification is both difficult and expensive due to the columns required to separate the two species. There is a need for an improved process for removing fluorosulfonic acid from HFSI to provide high purity HFSI for use as a starting material in the production of lithium bis (fluorosulfonyl) imide.

Disclosure of Invention

The present disclosure provides methods for producing purified bis (fluorosulfonyl) imide using gaseous ammonia.

In one form thereof, the present disclosure provides a method for producing a purified bis (fluorosulfonyl) imide. The method includes providing a liquid mixture comprising bis (fluorosulfonyl) imide and fluorosulfonic acid, and then contacting the liquid mixture with gaseous ammonia. The gaseous ammonia reacts with the fluorosulfonic acid to produce ammonium fluorosulfonate. The method further comprises separating the liquid mixture from the ammonium fluorosulfate.

Drawings

FIG. 1 shows crude HFSI¹⁹F NMR spectrum.

FIG. 2 illustrates a schematic representation of a system according to the present disclosure¹⁹F NMR spectrum comprising a portion of the spectrum of the purified HFSI amplified 128 fold after the first treatment of the crude HFSI of figure 1 with ammonia.

FIG. 3 illustrates a method according to the present disclosure¹⁹F NMR spectrum comprising a portion of the purified HFSI amplified 512 times after the second treatment of the purified HFSI of figure 2 with ammonia.

Detailed Description

The present disclosure provides a process for removing fluorosulfonic acid from a liquid mixture comprising fluorosulfonic acid and bis (fluorosulfonyl) imide (HFSI) to purify HFSI. Ammonia has been found to be useful for easily and inexpensively separating fluorosulfonic acid from HFSI. In the presence of HFSI, ammonia preferentially reacts with fluorosulfonic acid to produce ammonium fluorosulfonate according to formula 3:

equation 3: NH (NH)₃+HSO₃F→NH₄SO₃F。

Importantly, in some cases, such as when HFSI is produced by the reaction of urea with fluorosulfonic acid as shown in equation 1, the purification process does not introduce any new by-products into the product stream, as ammonium fluorosulfate has been produced in the synthesis of HFSI according to equation 1.

The concentration of fluorosulfonic acid in a liquid mixture comprising HFSI and fluorosulfonic acid prior to purification can be as low as about 0.001 mol% (mol%), about 0.002 mol%, about 0.005 mol%, about 0.01 mol%, about 0.02 mol%, about 0.05 mol%, about 0.1 mol%, about 0.2 mol%, about 0.5 mol%, about 1 mol%, about 2 mol%, about 5 mol%, or about 10 mol%, or as high as about 15 mol%, 20 mol%, about 25 mol%, about 30 mol%, about 35 mol%, about 40 mol%, about 45 mol%, about 50 mol%, about 55 mol%, about 60 mol%, about 65 mol%, or about 70 mol%, or within any range defined between any two of the foregoing values, such as, for example, about 0.001 mol% to about 70 mol%, about 0.002 mol% to about 65 mol%, about 0.005 mol% to about 60 mol%, about 0.01 mol% to about 55 mol%, about 0.02 mol% to about 50.05 mol%, about 0.05 mol% to about 40 mol%, about 0.002 mol%, about 65 mol% to about 45 mol%, or about 0.5 mol%, about 1 mol%, about 2 mol%, about 5 mol%, about 1 mol%, about 2 mol%, or about 5 mol%, or about 1 mol%, about 2 mol%, or about 5 mol%, or about 15 mol%, or about 30 mol%, or about 70 mol%, or about 0.0.0.0.0.0.0.0.0.0 mol%, or more, About 0.2 mol% to about 35 mol%, about 0.5 mol% to about 30 mol%, about 1 mol% to about 25 mol%, about 2 mol% to about 20 mol%, about 5 mol% to about 15 mol%, about 0.5 mol% to about 50 mol%, about 1 mol% to about 40 mol%, about 2 mol% to about 30 mol%, about 5 mol% to about 20 mol%, about 1 mol% to about 10 mol%, or about 0.1 mol% to about 20 mol%.

Removing fluorosulfonic acid from HFSI includes contacting a liquid mixture comprising HFSI and fluorosulfonic acid with gaseous ammonia, such that the gaseous ammonia reacts with fluorosulfonic acid to produce ammonium fluorosulfonate, as shown in equation 3. Contacting the liquid mixture with gaseous ammonia can include introducing gaseous ammonia into a headspace of a vessel containing the liquid mixture, and optionally agitating the mixture. When ammonia reacts with fluorosulfonic acid, the pressure in the vessel will decrease. When the pressure in the vessel no longer decreased, indicating that the reaction was substantially complete. The temperature of the reaction is not critical.

Alternatively or additionally, contacting the liquid mixture with gaseous ammonia may comprise bubbling gaseous ammonia through the liquid mixture. Alternatively or additionally, contacting the liquid mixture with gaseous ammonia may comprise flowing the liquid mixture and gaseous ammonia through a reflux column.

The gaseous ammonia may be supplied to the reaction at an absolute pressure as low as about 100 kilopascals (kPa), about 110kPa, about 120kPa, about 130kPa, or about 140kPa, or as high as about 150kPa, about 160kPa, about 170kPa, about 180kPa, about 190kPa, or about 200kPa, or any range defined between any two of the foregoing values, such as, for example, from about 100kPa to about 200kPa, from about 110kPa to about 190kPa, from about 120kPa to about 180kPa, from about 130kPa to about 170kPa, from about 140kPa to about 160kPa, from about 140kPa to about 150kPa, or from about 150kPa to about 160 kPa.

Separating the liquid mixture from the ammonium fluorosulfate can include filtering solid ammonium fluorosulfate from the liquid mixture. Alternatively or additionally, separating the liquid mixture from the ammonium fluorosulfate can include spray drying solid ammonium fluorosulfate from the liquid mixture. Alternatively or additionally, separating the liquid mixture from the ammonium fluorosulfate can include flashing HFSI from the ammonium fluorosulfate, leaving solid ammonium fluorosulfate.

After separating the ammonium fluorosulfate from the liquid mixture, the concentration of HFSI in the liquid mixture may be as low as about 90 mol%, about 92 mol%, about 94 mol%, about 95 mol%, about 96 mol%, or about 97 mol%, or as high as about 98 mol%, about 98.5 mol%, about 99 mol%, about 99.5 mol%, about 99.7 mol%, or about 99.9 mol%, or within any range defined between any two of the foregoing values, such as, for example, about 90 mol% to about 99.9 mol%, about 92 mol% to about 99.7 mol%, about 94 mol% to about 99.5 mol%, about 95 mol% to about 99 mol%, about 96 mol% to about 98.5 mol%, about 97 mol% to about 98 mol%, or about 98.5 mol% to about 99.9 mol%.

Optionally, the process of contacting the liquid mixture comprising HFSI and fluorosulfonic acid with gaseous ammonia and then separating the liquid mixture from ammonium fluorosulfate as described above can be repeated as many times as necessary to eliminate residual fluorosulfonic acid and to separate additional ammonium fluorosulfate to further purify HFSI.

The concentration of residual fluorosulfonic acid in the liquid mixture comprising HFSI and fluorosulfonic acid can be as low as about 0.005 mole percent (mol%), about 0.007 mol%, about 0.01 mol%, about 0.02 mol%, about 0.03 mol%, about 0.04 mol%, about 0.5 mol%, about 0.06 mol%, about 0.08 mol%, about 0.1 mol%, about 0.15 mol%, or about 0.2 mol%, or as high as about 0.3 mol%, about 0.5 mol%, about 1 mol%, about 1.5 mol%, about 2 mol%, about 3 mol%, about 5 mol%, about 10 mol%, about 15 mol%, or about 20 mol%, or within any range defined between any two of the foregoing values, such as, for example, about 0.005 mol% to about 20 mol%, about 0.007 mol% to about 15 mol%, about 0.01 mol% to about 10 mol%, about 0.02 mol% to about 5 mol%, about 0.03 mol% to about 0.04 mol%, about 0.04 mol% to about 2 mol%, about 0.05 mol% to about 2 mol%, about 0.5 mol%, about 0.06 mol%, or about 0.15 mol%, or about 0.2 mol%, or about 20 mol%, or more, or less, or more, of the foregoing values, or less, or more, or less, or more, of the like, or less, or more, or less, or more, or less, or more, or less, or more, or less, or more, of the presence or more, or less, or more, or less, or more, or less, or more, or less, or more, or less, or more, or less, or, About 0.08 mol% to about 0.5 mol%, about 0.1 mol% to about 0.3 mol%, about 0.15 mol% to about 0.2 mol%, or about 0.1 mol% to about 2 mol%.

After separating the additional ammonium fluorosulfate from the liquid mixture, the concentration of HFSI in the liquid mixture may be as low as about 95 mol%, about 96 mol%, or about 97 mol%, about 98 mol%, or about 98.5 mol%, or as high as about 99 mol%, about 99.5 mol%, about 99.7 mol%, about 99.9 mol%, or about 99.95 mol%, or within any range defined between any two of the foregoing values, such as, for example, about 95 mol% to about 99.95 mol%, about 96 mol% to about 99.9 mol%, about 97 mol% to about 99.7 mol%, about 98 mol% to about 99.5 mol%, about 98.5 mol% to about 99 mol%, or about 99.5 mol% to about 99.95 mol%.

The process described herein is more energy efficient and capital efficient than processes known in the art that rely solely on distillation to remove fluorosulfonic acid from HFSI. Furthermore, unlike methods known in the art, the methods described herein do not introduce any additional water or organic solvent into the system. Thus, the present invention represents a significant improvement in the removal of fluorosulfonic acid from HFSI as compared to methods known in the art.

In some embodiments, the process may comprise distilling the liquid mixture comprising fluorosulfonic acid and HFSI prior to providing a mixture for purification according to the above process. If the distillation process only needs to produce a moderately pure HFSI, rather than relying on the processes described herein to further purify the HFSI to the desired quality, the energy and capital costs of removing fluorosulfonic acid from HFSI by distillation are significantly reduced.

The concentration of fluorosulfonic acid in the liquid mixture comprising HFSI and fluorosulfonic acid after distillation and before purification can be as low as about 0.1 mol%, about 0.5 mol%, about 1 mol%, about 2 mol%, about 4 mol%, or about 6 mol%, or as high as about 8 mol%, about 10 mol%, about 15 mol%, or about 20 mol%, or within any range defined between any two of the foregoing values, such as, for example, from about 0.1 mol% to about 20 mol%, from about 2 mol% to about 15 mol%, from about 4 mol% to about 10 mol%, from about 6 mol% to about 8 mol%, or from about 8 mol% to about 10 mol%.

As used herein, the phrase "within any range defined between any two of the preceding values" literally means that any range can be selected from any two values listed before such phrase, whether such values are in the lower portion of the list or in the upper portion of the list. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value. As used herein, the singular forms "a", "an" and "the" include the plural reference unless the context clearly dictates otherwise.

With respect to imprecise terms, the terms "about" and "approximately" are used interchangeably to refer to a measurement that includes the measurement and also includes any measurement that is reasonably close to the measurement. As understood and readily determined by one of ordinary skill in the relevant art, measurement values reasonably close to the measurement deviate from the measurement values by a relatively small amount. For example, such deviations may be attributable to measurement errors or minor adjustments to optimize performance. Where one of ordinary skill in the relevant art will not readily determine a value for such a relatively small difference, the terms "about" and "approximately" will be understood to refer to ± 10% of the stated value.

It should be understood that the above description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.

Examples

Example 1 removal of fluorosulfonic acid from HFSI Using Ammonia

In this example, the purification of a mixture of HFSI and fluorosulfonic acid using gaseous ammonia as described above is demonstrated. The starting mixture of HFSI and fluorosulfonic acid was analyzed by fluorine-19 nuclear magnetic resonance spectroscopy and was found to contain about 92.6 mol% HFSI and about 7.4 mol% fluorosulfonic acid.¹⁹The F NMR spectrum is shown in FIG. 1. The mixture was purified by introducing gaseous ammonia at an absolute pressure between about 130kPa and about 150kPa into the headspace of a flask containing a mixture of HFSI and fluorosulfonic acid. Using coated Teflon^TMThe magnetic stir bar of (a) stirs the contents of the flask. While monitoring the pressure, the flask was allowed to stand at room temperature. The reaction was observed to be exothermic, as the flask would heat up depending on the amount of fluorosulfonic acid present. After a pressure drop to a residual pressure of less than about 3kPa was observed and the flask was cooled to the ringAfter ambient pressure, another portion of gaseous ammonia was introduced into the headspace of the flask and the contents were stirred while monitoring the pressure. The process of refilling the headspace with gaseous ammonia and stirring is repeated until the pressure stabilizes well above the residual pressure level, indicating that the reaction is substantially complete. The mixture in the flask was flashed and the first distillate was recovered. The first distillate was a clear colorless liquid. The solid white powder remaining in the flask was analyzed by infrared spectroscopy and was confirmed to be ammonium fluorosulfate.

The first distillate was analyzed by fluorine-19 nuclear magnetic resonance spectroscopy and was found to contain about 98.8 mol% HFSI and about 1.2 mol% fluorosulfonic acid. FIG. 2 shows¹⁹F NMR spectrum, and a 128-fold magnification to enable accurate visualization of the portion of the spectral inset indicating the peak of fluorosulfonic acid. The first distillate was purified by introducing gaseous ammonia into the flask headspace comprising the first distillate at an absolute pressure between about 130kPa and about 150 kPa. Using coated Teflon^TMThe magnetic stir bar of (a) stirs the contents of the flask. While monitoring the pressure, the flask was allowed to stand at room temperature. After a pressure drop to a residual pressure of less than about 3kPa was observed and the flask was cooled to ambient pressure, another portion of gaseous ammonia was introduced into the headspace of the flask and the contents were stirred while monitoring the pressure. The process of refilling the headspace with gaseous ammonia and stirring is repeated until the pressure stabilizes well above the residual pressure level, indicating that the reaction is substantially complete. The first distillate in the flask was flashed and the second distillate was recovered. The second distillate was a clear colorless liquid.

The second distillate was analyzed by fluorine-19 nuclear magnetic resonance spectroscopy and was found to contain HFSI and no observable fluorosulfonic acid. FIG. 3 shows¹⁹F NMR spectrum, and 512-fold magnification to enable accurate visualization of the inset portion of the spectrum indicating the peak of fluorosulfonic acid. The absence of a peak indicative of fluorosulfonic acid indicates that no residual fluorosulfonic acid was observed even at 512-fold magnification of the spectrum.

Aspect(s)

Aspect 1 is a method of producing a purified bis (fluorosulfonyl) imide. The method comprises providing a liquid mixture comprising bis (fluorosulfonyl) imide and fluorosulfonic acid; contacting the liquid mixture with gaseous ammonia, wherein the gaseous ammonia reacts with the fluorosulfonic acid to produce ammonium fluorosulfonate; and separating the liquid mixture from the ammonium fluorosulfate.

Aspect 2 is the method of aspect 1, wherein in the step of providing, the concentration of the fluorosulfonic acid in the liquid mixture is about 0.001 mol% to about 70 mol%.

Aspect 3 is the method of aspect 1 or aspect 2, wherein contacting the liquid mixture with gaseous ammonia comprises introducing the gaseous ammonia into a headspace of a vessel containing the liquid mixture.

Aspect 4 is the method of aspect 3, wherein the gaseous ammonia is supplied at a pressure between about 100kPa and about 200 kPa.

Aspect 5 is the method of any one of aspects 1 to 4, wherein contacting the liquid mixture with gaseous ammonia comprises bubbling the gaseous ammonia into the liquid mixture.

Aspect 6 is the method of any one of aspects 1 to 4, wherein contacting the liquid mixture with gaseous ammonia comprises flowing the gaseous ammonia and the liquid mixture in a reflux column.

Aspect 7 is the method of any one of aspects 1 to 6, wherein separating the liquid mixture from the ammonium fluorosulfate comprises filtering the ammonium fluorosulfate from the liquid mixture.

Aspect 8 is the method of any one of aspects 1 to 6, wherein separating the liquid mixture from the ammonium fluorosulfate comprises flashing the bis (fluorosulfonyl) imide from the ammonium fluorosulfate.

Aspect 9 is the method of any one of aspects 1 to 8, wherein the concentration of bis (fluorosulfonyl) imide in the liquid mixture is about 90 mol% to about 99.95 mol% after separating the ammonium fluorosulfonate from the liquid mixture.

Aspect 10 is the method of any one of aspects 1 to 9, further comprising:

providing the liquid mixture after separating the liquid mixture from the ammonium fluorosulfate, the liquid mixture comprising the bis (fluorosulfonyl) imide and residual fluorosulfonic acid;

contacting the liquid mixture with gaseous ammonia, wherein the gaseous ammonia reacts with the residual fluorosulfonic acid in the liquid mixture to produce additional ammonium fluorosulfate; and separating the liquid mixture from the additional ammonium fluorosulfate.

Aspect 11 is the method of aspect 10, wherein in the step of providing, the concentration of residual fluorosulfonic acid in the liquid mixture is about 0.005 mol% to about 20 mol%.

Aspect 12 is the method of aspect 10 or aspect 11, wherein contacting the liquid mixture with gaseous ammonia comprises introducing the gaseous ammonia into a headspace of a vessel containing the liquid mixture.

Aspect 13 is the method of aspect 12, wherein the gaseous ammonia is supplied at a pressure between about 100kPa and about 200 kPa.

Aspect 14 is the method of aspect 10 or aspect 11, wherein contacting the liquid mixture with gaseous ammonia comprises bubbling the gaseous ammonia into the liquid mixture.

Aspect 15 is the method of aspect 10 or aspect 11, wherein contacting the liquid mixture with gaseous ammonia comprises flowing the gaseous ammonia and the liquid mixture in a reflux column.

Aspect 16 is the method of any one of aspects 10-15, wherein separating the liquid mixture from the ammonium fluorosulfate comprises filtering the ammonium fluorosulfate from the liquid mixture.

Aspect 17 is the method of any one of aspects 10 to 15, wherein separating the liquid mixture from the ammonium fluorosulfate comprises flashing the bis (fluorosulfonyl) imide from the ammonium fluorosulfate.

Aspect 18 is the method of any one of aspects 10 to 17, wherein the concentration of bis (fluorosulfonyl) imide in the liquid mixture is about 98 mol% to about 99.95 mol% after separating the additional ammonium fluorosulfonate from the liquid mixture.

Aspect 19 is the method of any one of aspects 10 to 18, further comprising distilling the liquid mixture comprising bis (fluorosulfonyl) imide and fluorosulfonic acid prior to the providing step.

Aspect 20 is the method of aspect 19, wherein in the step of providing, the concentration of fluorosulfonic acid in the liquid mixture is about 1 mol% to about 20 mol%.