Process for producing hydrogen bis(chlorosulfonyl)imide

Abstract

The present invention relates to a process for the production of hydrogen bis(chlorosulfonyl)imide (HCSI), said process comprising the following steps: (i) providing to a reactor a composition (H) comprising an amount (CSI-1) of chlorosulfonyl isocyanate, an amount (CSA-1) of chlorosulfonic acid, and at most 20% by weight, based on the total weight of the composition (H), of an amount (HCSI-1) of HCSI; and (ii) heating said composition (H). The present invention also relates to a method for recycling a composition (H) as defined above, said method comprising feeding said composition (H) to a reactor and heating said composition (H) at a temperature below 150°C.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to European Patent Application No. 22305803.3, filed before June 1, 2022, the entire content of which is incorporated herein by reference for all purposes.

[0002] This disclosure relates to a process for the production of hydrogen (chlorosulfonyl) imide (HCSI).

Background Art

[0003] Hydrogen bis(fluorosulfonyl) imide (HFSI), its corresponding salts, and ionic liquids containing the FSI anion have been shown to be useful in a variety of applications, such as but not limited to as electrolytes in lithium - ion batteries and ultracapacitors. Hydrogen bis(fluorosulfonyl) imide is a relatively strong acid and forms various stable metal salts. The lithium salt of bis(fluorosulfonyl) imide (LiFSI) is particularly useful in batteries and ultracapacitors. Hydrogen bis(chlorosulfonyl) imide (HCSI) is known to be the most important starting material for the production of HFSI.

[0004] There are many processes for producing HCSI. One of the known processes is called the "isocyanate route", which includes (i) reacting chlorosulfonyl isocyanate with chlorosulfonic acid to prepare a reaction mixture containing HCSI, a heavy fraction, and a light fraction, and (ii) distilling the reaction mixture to separate each of the light fraction, HCSI, and the heavy fraction.

[0005] The isolated light fraction, as obtained at the end of this process, is a dangerous waste because it is highly corrosive. Therefore, the waste management cost of the current isocyanate route is relatively high.

[0006] Chinese Patent Application No. 106044728 (in the name of QUZHOU CHEMSPEC CHEMICAL CO., LTD.) teaches a method for preparing imide-disulfuryl fluoride lithium salt. Example 4 shows that HCSI was produced by the isocyanate route. Specifically, chlorosulfonic acid was mixed with concentrated sulfuric acid, and the mixture was heated to 105 - 115 °C. Then, chlorosulfonyl isocyanate was added dropwise. After the addition, the temperature was gradually raised to 120 - 130 °C. Only the excess chlorosulfonyl isocyanate was separated from the main fraction for recycling, and most of the fraction was left untreated after the reaction.

[0007] International Publication No. WO 2009 / 123328 pamphlet (Nippon Shokubai Co., Ltd.) provides a method for producing fluorosulfonylimide such as N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide, di(fluorosulfonyl)imide and its salts, said method comprising a fluorination step of a chlorinated precursor. Example 2 of this document teaches a method for preparing hydrogen bis(chlorosulfonyl)imide (HCSI) by the reaction of chlorosulfonic acid (CSA) and chlorosulfonyl isocyanate (CSI), while the target hydrogen bis(chlorosulfonyl)imide (HCSI) is isolated from the reaction medium by distillation under reduced pressure.

SUMMARY OF THE INVENTION

[0008] The applicant recognized that there is still a need for an improved environmentally friendly manufacturing process for HCSI that features high HCSI yield, easy handling and recycling of light fractions, and low production of non-recyclable / unrecyclable products and low waste management costs.

[0009] It has now been discovered that the waste stream after isolation from the reaction mixture of the above isocyanate route and the composition (H) containing chlorosulfonyl isocyanate, chlorosulfonic acid and HCSI, which was previously thought to be, can be used for the production of HCSI.

[0010] The Applicant has unexpectedly found that the recycling of such a composition (H) for the synthesis of HCSI successfully increases the final yield of HCSI. Advantageously, the Applicant has found that the composition (H) can either be recycled to a complement of fresh chlorosulfonyl isocyanate and chlorosulfonic acid or used as such to produce HCSI without the use of further reactants.

Brief Description of the Drawings

[0011]

Figure 1

Modes for Carrying Out the Invention

[0012] In the present application: - The expression “... to...” should be understood to include the limit values; - Any description, even if described in relation to a particular embodiment, is applicable to and interchangeable with other embodiments of the present invention; - The expression “isocyanate route” is intended to denote a reaction comprising at least (i) a step of reacting chlorosulfonyl isocyanate with chlorosulfonic acid to prepare a reaction mixture containing HCSI, a heavy fraction and a light fraction, and (ii) a step of distilling the reaction mixture to separate each of the light fraction, HCSI and the heavy fraction; - When an element or component is said to be included in and / or selected from a list of enumerated elements or components, in the relevant embodiments explicitly considered herein, the element or component can be any one of the individual enumerated elements or components, or can also be selected from a group consisting of any two or more of the explicitly enumerated elements or components; it should be understood that any element or component enumerated in the list of elements or components can be omitted from such a list; - Any recitation herein of a numerical range by endpoints includes all numbers within the recited range, as well as the endpoints and equivalents.

[0013] In a first aspect, the present invention is a process for producing hydrogen bis(chlorosulfonyl)imide (HCSI), the process comprising the following steps: (i) providing to a reactor a composition (H) comprising chlorosulfonyl isocyanate in an amount (CSI-1), chlorosulfonic acid in an amount (CSA-1), and HCSI in an amount (HCSI-1) of at most 20% by weight, based on the total weight of the composition (H); (ii) heating the composition (H) to thereby obtain a mixture (M1) comprising HCSI in an amount (HSCI-2), where (HCSI-2) is more than (HCSI-1); The process relates to a process comprising.

[0014] Preferably, the molar ratio of the amount (CSI-1) of chlorosulfonyl isocyanate to the amount (CSA-1) of chlorosulfonic acid is equal to, for example, 1.00:1.01, 1.00:1.02, 1.00:1.03, 1.00:1.04, 1.00:1.05, 1.00:1.06, 1.00:1.07, 1.00:1.08, 1.00:1.09, 1.00:1.10 or any range between these values.

[0015] Preferably, the composition (H) contains HCSI in an amount (HCSI-1) of at most 15% by weight, more preferably at most 12% by weight, at most 10% by weight, at most 8% by weight, at most 5% by weight, at most 2% by weight or at most 1% by weight, based on the total weight of the composition (H).

[0016] Preferably, the composition (H) contains HCSI in an amount (HCSI-1) of at least 0.01% by weight, more preferably at least 0.05% by weight, based on the total weight of the composition (H).

[0017] The presence and amount of CSA, CSI and HCSI in the composition (H) and in the other compositions described in this description can be measured using spectroscopic analysis techniques such as Raman or near-IR, for example.

[0018] Advantageously, the composition (H) is isolated from one or more reaction mixtures of the isocyanate route as defined above. The composition (H) is also referred to as a "light fraction". Thus, advantageously, in the process according to the present disclosure, the separated light fraction is recycled and reused, thus significantly reducing the waste management costs of the isocyanate route.

[0019] The composition (H) can be heated in the presence or absence of an additional catalyst in step (ii).

[0020] Optionally, the composition (H) is heated in the presence of a catalyst.

[0021] The catalyst is not particularly limited. The catalyst can be an acid, preferably a protonic acid and / or a Lewis acid. A Lewis acid is generally based on the Lewis acid-base theory and generally refers to a substance that accepts an electron pair. The Lewis acid can be selected from the group consisting of NiCl2, FeCl2, FeCl3, CoCl3, ZnCl2 and MnCl2. A protonic acid generally refers to a molecule or ion that can release a proton (hydrogen ion, H+). The protonic acid can be concentrated sulfuric acid and / or fuming sulfuric acid. Concentrated sulfuric acid generally refers to a sulfuric acid solution having a mass percentage of 70% or more, more particularly a sulfuric acid solution having a mass percentage of 98% or more. Fuming sulfuric acid (HSO4·xSO3) generally refers to a sulfuric acid solution of sulfur trioxide, more particularly a sulfuric acid solution of sulfur trioxide having a mass percentage of 20% or more.

[0022] According to an embodiment, the catalyst can be added to the composition (H). For example, the catalyst is added to the composition (H) in step (i) or before starting step (ii).

[0023] Alternatively, the catalyst can be generated in situ. For example, the catalyst is generated subsequently as step (ii) proceeds.

[0024] Optionally, at least one additional substance can be present in step (ii). For example, such at least one additional substance can promote the synthesis of HCSI. According to one embodiment, the at least one additional substance can be added in step (ii). Alternatively or simultaneously, the at least one additional substance is in admixture with the starting materials, preferably with the CSI and / or CSA provided under step (ii).

[0025] The amount of the at least one additional substance is not limited. Preferably, the amount of the at least one additional substance is calculated based on the reaction conditions and the selected starting materials.

[0026] According to a preferred embodiment, said at least one additional substance is water. Such water can be present in trace amounts in the reactor and / or in one or more of the starting materials, in particular in chlorosulfonic acid (CSA).

[0027] Preferably, the weight ratio of water to the composition (H) is from 0.0001:1 to 0.001:1.

[0028] Without being bound by any theory, the Applicant believes that the presence of water in the reactor generates sulfuric acid which functions sequentially as a catalyst, optionally in the presence of other by-products.

[0029] Preferably, step (ii) is carried out by heating at a temperature of at least 40 °C and at most 150 °C, preferably at least 60 °C, more preferably at least 80 °C. More preferably, said heating is carried out at a temperature of 115 °C to 145 °C, even more preferably 120 °C to 140 °C.

[0030] The heating time of step (ii) is not limited. Advantageously, the heating time is determined by monitoring the conversion rate of chlorosulfonyl isocyanate according to methods known in the art.

[0031] According to a preferred embodiment, the process for producing hydrogensulfide bis(chlorosulfonyl)imide (HCSI) according to the invention, after step (ii), (iii) treating said mixture (M1) to recover a composition (C2) comprising an amount (HCSI-3) of HCSI, an amount (CSI-4) of chlorosulfonyl isocyanate, an amount (CSA-4) of chlorosulfonic acid, and an amount (HCSI-4) of HCSI of at most 20% by weight, based on the total weight of the composition (C2), wherein the amount (HCSI-3) is greater than the amount (HCSI-4).

[0032] At the end of step (iii), it will be understood that the sum of the amounts HCSI-3 and HCSI-4 is equal to the amount HCSI-2 at the end of step (ii) ± 1 wt% or less.

[0033] Preferably, steps (ii) and (iii) are carried out simultaneously. Alternatively, steps (ii) and (iii) are carried out successively. For example, the heating in step (ii) is stopped before starting step (iii).

[0034] In step (iii), the method for recovering the composition (C2) and optionally HCSI from the mixture (M1) obtained in step (ii) is not particularly limited.

[0035] A preferred method can be distillation.

[0036] Optimal distillation conditions (such as pressure and temperature) and equipment can be appropriately selected to recover the composition (C2) containing CSI-4 and CSA-4 with a maximum of 20 wt% of HCSI.

[0037] If necessary depending on the situation, two or more distillation steps can be carried out to recover the composition (C2) and optionally HCSI.

[0038] For example, good results have been obtained by carrying out at least one distillation under reduced pressure to recover the composition (C2).

[0039] More preferably, the at least one distillation is carried out at a pressure of 40 - 5 mbar absolute (4000 Pa - 500 Pa). More preferably, the at least one distillation is carried out by maintaining the distillation device at a temperature of 30°C - 140°C.

[0040] For example, two or more distillation steps are carried out in step (iii).

[0041] According to this embodiment, the first distillation is carried out at a pressure of 40 to 20 mbar absolute (4000 Pa to 2000 Pa).

[0042] Preferably, the further distillation is carried out at a pressure of 30 to 5 mbar absolute (3000 Pa to 500 Pa).

[0043] Preferably, the first distillation is carried out by maintaining the distillation device at a temperature of 30 to 130 °C.

[0044] Preferably, the further distillation is carried out by maintaining the distillation device at a temperature of 40 to 160 °C.

[0045] The optimal distillation conditions (e.g., pressure and temperature) and apparatus can be appropriately selected to recover HCSI.

[0046] For example, good results have been obtained by carrying out distillation at least once under reduced pressure to recover HCSI. Preferably, the at least one distillation is carried out at a pressure of 1 to 10 mbar absolute (100 Pa to 1000 Pa). Preferably, the at least one distillation is carried out by maintaining the distillation device at a temperature of 100 °C to 160 °C.

[0047] For example, good results are obtained in the present invention when at least one distillation step is carried out to recover the composition (C2) and at least one distillation step is carried out to recover HCSI.

[0048] Preferably, in step (ii), the composition (H) is heated in the presence of chlorosulfonyl isocyanate and chlorosulfonic acid. It will be understood that chlorosulfonyl isocyanate and chlorosulfonic acid are newly added in the process of the present invention and in total up to the amount of chlorosulfonyl isocyanate and chlorosulfonic acid already present in the reactor.

[0049] According to this embodiment, step (ii) includes supplying an amount (CSI-2) of chlorosulfonyl isocyanate and an amount (CSA-2) of chlorosulfonic acid to the reactor.

[0050] According to this embodiment, the weight ratio of the composition (H) to the total of the amount (CSI-2) of chlorosulfonyl isocyanate and the amount (CSA-2) of chlorosulfonic acid is at least 0.001:1 before heating.

[0051] Preferably, the weight ratio of the composition (H) to the total of the amount (CSI-2) of chlorosulfonyl isocyanate and the amount (CSA-2) of chlorosulfonic acid is at least 0.005:1, preferably at least 0.01:1, more preferably at least 0.035:1 before heating.

[0052] Preferably, the weight ratio of the composition (H) to the total of the amount (CSI-2) of chlorosulfonyl isocyanate and the amount (CSA-2) of chlorosulfonic acid is at most 1:1, preferably at most 0.75:1, preferably at most 0.50:1, more preferably 0.35:1 before heating.

[0053] Advantageously, the weight ratio of the composition (H) to the total of the amount (CSI-2) of chlorosulfonyl isocyanate and the amount (CSA-2) of chlorosulfonic acid is in the range of 0.02:1 to 0.4:1, preferably 0.05:1 to 0.25:1 before heating.

[0054] Preferably, the molar ratio of the amount (CSI-2) of chlorosulfonyl isocyanate to the amount (CSA-2) of chlorosulfonic acid is 1:1 to 1:20, preferably 1:1 to 1:10, more preferably 1:1 to 1:5, still more preferably 1:1 to 1:2, and most preferably 1:1 to 1:1.1.

[0055] When chlorosulfonyl isocyanate and chlorosulfonic acid are present in step (ii), the process according to the invention preferably comprises the step: (ii-a) Adding chlorosulfonic acid in an amount (CSA-2) to the composition (H) to obtain a mixture (M*); (ii-b) Adding chlorosulfonyl isocyanate in an amount (CSI-2) to the mixture (M*); and the method includes the above steps.

[0056] Preferably, the mixture (M*) is heated before step (ii-b).

[0057] Preferably, the heating is carried out at a temperature of 100°C to 120°C.

[0058] Preferably, the temperature is maintained at 100°C to 120°C in step (ii-b).

[0059] Step (ii-a) can be carried out by adding chlorosulfonic acid either all at once (also referred to as the "batch mode") or gradually (also referred to as the "feed mode").

[0060] Step (ii-b) can be carried out by adding chlorosulfonyl isocyanate either all at once or gradually.

[0061] The process of the present disclosure can be adapted to batch, feed, or continuous modes.

[0062] Some or all of the steps of the process according to the present invention are preferably carried out in a reactor that can withstand the corrosion of the reaction medium. For this reason, a corrosion-resistant material is selected for the part of the reactor that comes into contact with the reaction medium.

[0063] Preferably, the corrosion-resistant material is an alloy based on molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon, and tungsten, such as Hastelloy® C276, which is commercially available under the trade name Hastelloy®; an alloy of nickel, chromium, iron, and manganese, such as Inconel® 600, 625, or 718, which is commercially available under the trade name Inconel® or Monel TM and is selected from those with copper and / or molybdenum added thereto.

[0064] The corrosion-resistant material can be selected from stainless steels, more specifically, stainless steels such as 304, 304L, 316, or 316L stainless steel. Preferably, steel having a nickel content of at most 22 wt%, preferably 6 wt% - 20 wt%, more preferably 8 wt% - 14 wt% is used. 304 and 304L steels have a nickel content that varies from 8 wt% - 12 wt%, and 316 and 316L steels have a nickel content that varies from 10 wt% - 14 wt%. More preferably, 316L steel is selected.

[0065] The corrosion-resistant material can be a polymeric material that is resistant to corrosion of the reaction medium and provides a coating on the part of the reactor that contacts the reaction medium. Examples include PTFE (polytetrafluoroethylene, i.e., Teflon) or PFA (perfluoroalkyl resin).

[0066] As an alternative and more preferably, the corrosion-resistant material is selected from glass, glass-lined, and enamel devices.

[0067] Preferably, before step (i), the following step: 0-a) contacting chlorosulfonyl isocyanate with chlorosulfonic acid to thus obtain a mixture (M) containing HCSI, chlorosulfonyl isocyanate, and chlorosulfonic acid; 00-a) treating the mixture (M) to thus obtain HCSI and a composition (H) as defined above is carried out.

[0068] In such step 0-a), chlorosulfonyl isocyanate and chlorosulfonic acid are preferably brought into contact under heating.

[0069] Preferably, the heating is carried out at a temperature of 100°C to 160°C.

[0070] Step 0-a) and step 00-a) can be carried out at the same temperature.

[0071] Alternatively, step 0-a) is carried out at a temperature of 110°C to 130°C, and step 00-a) is carried out at a temperature of 120°C to 160°C. According to an embodiment, the temperature is raised to, for example, 120°C to 160°C before starting step 00-a).

[0072] Preferably, step 00-a) is carried out by maintaining the temperature at 100°C to 160°C.

[0073] Preferably, the step 00-a) is carried out by distillation.

[0074] According to an embodiment, the composition (C2) obtained in step (iii) is recovered and can be fed to the reactor in step (i) or step (ii), and as a result, the composition (C2) is recycled. It will be understood that such a composition (C2) is used as the composition (H) in the process of the present invention.

[0075] According to this embodiment, the process according to the present invention, after step (iii), has the following steps: (iv) feeding the composition (C2) to the reactor; (v) Heating the composition (C2) to thereby obtain a mixture (M2) comprising an amount (HCSI-5) of HCSI, an amount (CSI-5) of chlorosulfonyl isocyanate, and an amount (CSA-5) of chlorosulfonic acid, wherein HCSI-5 is more than HCSI-4, CSI-5 is less than CSI-4, and CSA-5 is less than CSA-4; (vi) Treating the mixture (M2) to recover the composition (C3) comprising an amount (CSI-7) of chlorosulfonyl isocyanate, an amount (CSA-7) of chlorosulfonic acid, and, based on the total weight of the composition (C3), an amount (HCSI-7) of HCSI of at most 20% by weight, and optionally an amount HCSI-6 of HCSI, wherein HCSI-7 is less than HCSI-5; (vii) Optionally, repeating steps (iv), (v), and (vi) at least once by feeding the composition (C3) to a reactor, heating it, and recovering the composition (Cx) comprising an amount (CSI-x) of chlorosulfonyl isocyanate, an amount (CSA-x) of chlorosulfonic acid, and, based on the total weight of the composition (Cx), an amount (HCSI-x) of HCSI of at most 20% by weight, and optionally HCSI; comprising; provided that HCSI is recovered in at least one of steps (vi) or (vii), wherein "x" in (Cx), (CSI-x), and (CSA-x) represents different amounts for each compound obtained each time steps (iv) to (vi) are repeated.

[0076] It will be understood that at the end of step (vi), the sum of the amounts HCSI-6 and HCSI-7 is equal to the amount HCSI-5 at the end of step (v) ± 1% by weight or less.

[0077] Each of steps (ii), (v), and (vii) can be carried out independently in the presence of chlorosulfonyl isocyanate and chlorosulfonic acid.

[0078] Preferably, the said step (v) of heating is carried out in the presence of an amount (CSI-6) of chlorosulfonyl isocyanate and an amount (CSA-6) of chlorosulfonic acid.

[0079] Preferably, the weight ratio of the composition (C2) to the total of the amount (CSI-6) of chlorosulfonyl isocyanate and the amount (CSA-6) of chlorosulfonic acid is at least 0.001:1 before heating.

[0080] According to an alternative embodiment, the composition (C2) obtained in step (iii) is recovered and fed into a suitable container. According to this embodiment, any of the different compositions - in particular, the composition (H), the composition (C2), the composition (C3), and the composition (Cx) recovered from different reactions or reaction mixtures of the isocyanate route - are fed into the same container or into different containers. Such compositions can then be combined together and fed under step (i) of the process of the invention as the composition (H).

[0081] The parameters of the process according to the invention can be suitably selected and optimized based on, for example, the starting materials (in particular, the amounts of other compounds in the starting CSI and CSA, such as their purity) and the scale at which the process is carried out, for example, whether the process is carried out on an industrial scale or on a laboratory scale.

[0082] In a second aspect, the present invention relates to a method for recycling a composition comprising chlorosulfonyl isocyanate, chlorosulfonic acid, and up to 20% by weight of HCSI, the method comprising feeding the composition into a reactor and heating the composition at a temperature of at least 40°C and at most 150°C, optionally in the presence of chlorosulfonyl isocyanate and chlorosulfonic acid.

[0083] Preferably, the heating is carried out at a temperature of 115°C to 145°C, more preferably 120°C to 140°C.

[0084] Advantageously, the HCSI obtained at the end of the process according to the invention is suitable for use in subsequent manufacturing processes of bis(fluorosulfonyl)imide or a salt thereof or a salt of bis(chlorosulfonyl)imide.

[0085] Preferably, said salt is an ammonium salt or a salt with an alkali metal or alkaline earth metal.

[0086] According to a preferred embodiment, said salt of bis(fluorosulfonyl)imide or bis(chlorosulfonyl)imide is selected from ammonium, sodium or lithium.

[0087] The present disclosure will hereinafter be described in connection with the following examples, the purpose of which is merely illustrative and is not intended to limit the scope of the invention.

[0088] If the disclosure of any patent, patent application, and publication incorporated herein by reference conflicts with the description of this application to the extent that it may obscure a term, the description shall control.

Examples

[0089] Raw materials Chlorosulfonyl isocyanate (ClSO2NCO): CAS No. 1189 - 71 - 5, commercially available from Lonza Ltd. or synthesized according to known procedures. Chlorosulfonic acid (ClSO3H): CAS No. 7790 - 94 - 5, commercially available from Sigma - Aldric. Composition "light fraction": internally synthesized within Solvay.

[0090] Test methods Differential Scanning Calorimetry (DSC): For purity measurement by DSC, the measurement conditions were optimized to some extent and followed ASTM E928-19. The 20 samplings of HCSI must be carried out under a strictly inert atmosphere using crucibles made of stainless steel or gold-coated with excellent pressure resistance. DSC is performed using samples in the range of 10 - 30 mg. The melting peaks obtained after at least 2 and in some cases up to 4 melting / crystallization cycles are integrated by the DSC software. As an example, the DSC method used was defined as follows: 1 cycle (-30°C to 150°C at 5°C / min) (4 melts / 3 crystallizations) (duration 4 hours 12 minutes) under a 25 N2 gas flow of 50 mL / min. As another example, a DSC device manufactured by Mettler Toledo was used for analytical development. In this device, the software that commands the device to perform data analysis was also STARe software, version 11.00a (Build 4393), manufactured by Mettler Toledo. Other DSC devices can be used similarly. The crucibles and membranes used for HCSI DSC analysis can be selected from 30 various reference numbers such as the following manufactured by Mettler Toledo: - Crucible made of HP steel: 51140404 - HP gold-coated crucible: 51140405 - Gold-coated disposable membrane: 51140403

[0091] The molar purity can be estimated by the "Purity" or "Purity Plus" function of the software that applies the Van't Hoff law formula. The DSC purity determination can be regarded as a super melting point determination. The DSC purity determination is based on the fact that impurities lower the eutectic melting point.

Number

[0092] The simplified formula is

Number

[0093] In both cases, the reciprocal of the melting rate (1 / F) is given by the following equation: [Number] (where A part is the partial area of the DSC peak; A tot is the total area of the peak, and c is the linear approximation coefficient) is given by.

[0094] Example 1: Synthesis of HCSI via the isocyanate route (comparison) Chlorosulfonic acid (CSA - 145.70 g) was charged at room temperature into a pre-inactivated mechanically stirred double-jacketed 0.25 L glass stirred tank reactor equipped with a baffle, a four-blade stirring shaft, a double-jacketed distillation head connected to a fraction separator with a double jacket, and two temperature probes, and the whole setup was connected to a basic scrubber. The vessel was heated at 120 °C (condenser at -10 °C). Chlorosulfonyl isocyanate (CSI - 167.50 g) was added using a syringe pump over 4 hours and 15 minutes. The mixture was heated from 120 °C to 140 °C and maintained for 17 hours. The mixture was pre-distilled under reduced pressure (T ボイラー=92~117 °C; P = 30~8.5 mbar absolute = 3000~8500 Pa), and after about 2 hours, 18.10 g of the light fraction [Composition (H)] (T ヘッド =25~72 °C) was isolated. The resulting mixture was further distilled, and after about 5 to 6 hours, two HCSI fractions (T ボイラー =120~145 °C; T ヘッド =115~118 °C, P = about 2~4 mbar absolute = 200~400 Pa) were isolated.

[0095] The mass of the isolated HCSI was 196.50 g (77.6%).

[0096] The remaining heavy fraction (17.13 g) was separated and treated.

[0097] Example 2: Synthesis of HCSI by the isocyanate route doped with about 10% of the composition (H) according to the present invention The same protocol found in Example 1 was reproduced using chlorosulfonic acid (148 g) finished with 29.2 g of the light fraction [Composition (H)] (obtained from the previous trial). Chlorosulfonyl isocyanate (170.10 g) was added at 120 °C over 4 h, and the protocol was continued as described in Example 1. The resulting mixture was pre-distilled under reduced pressure (T ボイラー =88~118 °C; P = 28~8 mbar absolute = 2800~800 Pa), and after about 2 hours, 32.60 g of the light fraction (T ヘッド =35~70 °C) was isolated. The resulting mixture was further distilled, and after about 5 to 6 hours, two HCSI fractions (T ボイラー =110~129 °C; T ヘッド =74~106 °C, P = 4 mbar absolute = 400 Pa) were isolated.

[0098] The mass of the isolated HCSI was 212.20 g (82.7%).

[0099] The remaining heavy fraction (12.83 g) was separated and treated.

[0100] Compared with Example 1, the yield of HSCI increased by 5.1 wt% when doped with 10% light fraction, and the remaining heavy fraction decreased by about 30 wt%.

[0101] The quality of HSCI was acceptable as shown in Figure 1.

[0102] Example 3: Synthesis of HCSI by the isocyanate route doped with about 20% of the composition (H) according to the present invention The same protocol found in Example 1 was reproduced using chlorosulfonic acid (143 g) finished with 62.80 g of light fraction [composition (H)] (combined from three different pre-trials). Chlorosulfonyl isocyanate (165.40 g) was added at 120 °C over 4 h, and the protocol was continued as described in Example 1. The resulting mixture was pre-distilled under reduced pressure (T ボイラー = 83~115 °C; P = 29~7 mbar absolute = 2900~700 Pa) and after about 2 h, 41.00 g of light fraction (T ヘッド = 31~78 °C) was isolated. The resulting mixture was further distilled and after about 5~6 h, two HCSI fractions (T ボイラー = 110~111 °C; T ヘッド = 91~102 °C, P = 3~5 mbar absolute = 300~500 Pa) were isolated.

[0103] The mass of the isolated HCSI was 226.60 g (90.8%).

[0104] The remaining heavy fraction (16.90 g) was separated and treated.

[0105] Compared with Example 1, the yield of HSCI increased by 13.2 wt% when doped with 10% light fraction, and the remaining heavy fraction decreased by about 6 wt%.

[0106] The quality of HSCI was acceptable as shown in Figure 1.

[0107] Example 4: Synthesis of HCSI from 100% composition (H) according to the present invention In the same vessel as described in Example 1, 336.3 g of a combined light fraction (combined from three different pre-trials) was heated according to the same temperature ramp as in Example 1. The resulting mixture was pre-distilled under reduced pressure and after about 2 hours, the first light fraction (143.4 g, T ボイラー = 50 - 97 °C, T ヘッド = 31 - 78 °C, P = 30 mbar absolute = 3000 Pa) and the second light fraction (14.9 g, T ボイラー = 96 - 120 °C, T ヘッド = 40 - 50 °C, P = 7 - 20 mbar absolute = 700 - 2000 Pa) were isolated. The resulting mixture was further distilled and after about 5 - 6 hours, the first HCSI fraction (12.3 g, T ボイラー = 113 °C; T ヘッド = 106 °C, P = 4 mbar absolute = 400 Pa) and the second fraction (10.6 g, T ボイラー = 110 - 121 °C; T ヘッド = 96 - 104 °C, P = 4 mbar absolute = 400 Pa) were isolated. The mass of the isolated HCSI was 118.3 g. The remaining heavy fraction (9.1 g) was separated and treated separately.

[0108] The quality of HSCI was acceptable as shown in Figure 1 and thus could be used directly for the synthesis of NH4FSI as exemplified by Example 5.

[0109] Example 5: Synthesis of NH4FSI from the HCSI of Example 4 A pre-dried 0.5 L mechanically stirred reactor made of PTFE, equipped with a 4-blade stirring shaft, four baffles, a PTFE condenser, a PFA-based internal piping system connected to a thermostat (for internal heating purposes), and a heat-insulating outer layer, was charged with NH4F (76.9 g) and anhydrous EMC (303.1 g) under a nitrogen stream. The resulting slurry was preheated at 60 °C. The HCSI (101.5 g) obtained according to Example 4 was preheated at 60 °C and introduced in a molten form at a constant flow rate over 1 h. After the addition, the mixture was maintained at 84 °C for 3 h and then cooled to room temperature. The suspension was transferred to a Buchner-type filter equipped with a 0.22-μm PTFE membrane under a nitrogen stream. The emptied reactor was washed with additional EMC (154.5 g) and further used to wash the solid cake. The combined filtrate obtained (472.1 g) 19 showed a yield of 96.3% of NH4FSI (88.9 g) as measured by 19F NMR (Bruker Avance 400 NMR).

Claims

1. A method for producing hydrogen bis(chlorosulfonyl)imide (HCSI), wherein the method comprises the following steps: (i) Providing a reactor with a composition (H) comprising a quantity of (CSI-1) chlorosulfonyl isocyanate, a quantity of (CSA-1) chlorosulfonic acid, and a maximum of 20% by weight of (HCSI-1) HCSI based on the total weight of composition (H), (ii) The step of heating the composition (H) to obtain a mixture (M1) containing an amount of (HCSI-2) of HCSI, wherein (HCSI-2) is greater than (HCSI-1), and Methods that include...

2. The above composition (H) is - A maximum of 15% by weight, more preferably a maximum of 12% by weight, based on the total weight of composition (H); and / or - Based on the total weight of composition (H), at least 0.01% by weight, preferably at least 0.05% by weight The method according to claim 1, comprising HCSI in an amount of (HCSI-1).

3. The method according to claim 1, wherein step (ii) is performed at a temperature of 40 to 150°C.

4. After step (ii), (iii) A step of processing the mixture (M1) to recover a composition (C2) containing an amount of (HCSI-3) of HCSI, an amount of (CSI-4) of chlorosulfonyl isocyanate, an amount of (CSA-4) of chlorosulfonic acid, and an amount of (HCSI-4) of HCSI that is at most 20% by weight of the total weight of composition (C2), wherein the amount of (HCSI-3) is greater than the amount of (HCSI-4). The method according to claim 1, including the method described in claim 1.

5. The method according to claim 4, wherein in step (iii), at least one distillation under reduced pressure is performed to recover the composition (C2).

6. The method according to claim 5, wherein the at least one distillation is carried out at a pressure of 40 to 5 mbar (absolute pressure) (4000 Pa to 500 Pa) and / or by maintaining the distillation device at a temperature of 30°C to 140°C.

7. The method according to claim 4, wherein in step (iii), at least two distillation steps are performed to recover composition (C2).

8. - The first distillation is carried out at a pressure of 40 to 20 mbar (absolute pressure) (4000 Pa to 2000 Pa) and / or by maintaining the distillation device at a temperature of 30 to 130°C, - At least further distillation is carried out at a pressure of 30 to 5 mbar (absolute pressure) (3000 Pa to 500 Pa) and / or by maintaining the distillation device at a temperature of 40 to 160°C. The method according to claim 7.

9. The method according to claim 4, wherein in step (iii), at least one distillation under reduced pressure is performed to recover the HCSI, preferably the at least one distillation is performed at a pressure of 1 to 10 mbar (absolute pressure) (100 Pa to 1000 Pa) and / or the distillation device is kept at a temperature of 100 to 160°C.

10. The method according to claim 1, wherein step (ii) is carried out by supplying an amount (CSI-2) of chlorosulfonyl isocyanate and an amount (CSA-2) of chlorosulfonic acid.

11. The method according to claim 10, wherein the weight ratio of composition (H) to the total amount of chlorosulfonyl isocyanate (CSI-2) and chlorosulfonic acid (CSA-2) is at least 0.001:1 before heating.

12. The weight ratio of composition (H) to the total amount of chlorosulfonyl isocyanate (CSI-2) and chlorosulfonic acid (CSA-2) is, - Before heating, the ratio is at least 0.005:1, preferably 0.01:1, more preferably 0.035:1; and / or - Before heating, the ratio is at most 1:1, preferably 0.75:1, preferably 0.50:1, and more preferably 0.35:

1. The method according to claim 10.

13. The method according to claim 10, wherein the molar ratio of (CSI-2) chlorosulfonyl isocyanate to (CSA-2) chlorosulfonic acid is 1:1 to 1:20, preferably 1:1 to 1:

10.

14. Before step i), step: 0-a) The step of contacting chlorosulfonyl isocyanate with chlorosulfonic acid to obtain a mixture (M*); 00-a) The step of processing the mixture (M*) to obtain HCSI, a composition (H) containing (CSI-1) chlorosulfonyl isocyanate, a (CSA-1) chlorosulfonic acid, and at most 20% by weight of (HCSI-1) HCSI based on the total weight of composition (H), The method according to claim 1, including the method described in claim 1.

15. After step (iii), follow these steps: (iv) The step of supplying the composition (C2) to the reactor; (v) Heat the composition (C2) to obtain a mixture (M2) comprising (HCSI-5) of HCSI, (CSI-5) of chlorosulfonyl isocyanate and (CSA-5) of chlorosulfonic acid, wherein the amount of HCSI-5 is greater than that of HCSI-4, the amount of CSI-5 is less than that of CSI-4, and the amount of CSA-5 is less than that of CSA-4; (vi) A step of processing the mixture (M2) to recover composition (C3) containing an amount of (CSI-7) chlorosulfonyl isocyanate, an amount of (CSA-7) chlorosulfonic acid, and an amount of (HCSI-7) of HCSI that is at most 20% by weight of the total weight of composition (C3), and optionally an amount of HCSI-6 of HCSI, wherein HCSI-7 is less than HCSI-5; (vii) optionally supply composition (C3) to a reactor, heat it, and recover composition (Cx) containing (CSI-x) chlorosulfonyl isocyanate, (CSA-x) chlorosulfonic acid, and at most 20% by weight of (HCSI-x) HCSI based on the total weight of composition (Cx), and optionally the HCSI, thereby repeating steps (iv), (v), and (vi) at least once. Including; However, provided that HCSI is recovered in at least one of step (vi) or (vii), Here, "x" in (Cx), (CSI-x), and (CSA-x) indicates that the amount of each compound obtained differs each time steps (iv) to (vi) are repeated. The method according to claim 4.

16. The method according to claim 15, wherein, in step (v), composition (C2) is heated in the presence of a quantity of (CSI-6) chlorosulfonyl isocyanate and a quantity of (CSA-6) chlorosulfonic acid, and the weight ratio of composition (C2) to the total of (CSI-6) chlorosulfonyl isocyanate and (CSA-6) chlorosulfonic acid is at least 0.001:1 before heating.

17. A method for recycling a composition comprising chlorosulfonyl isocyanate, chlorosulfonic acid, and at most 20% by weight of HCSI, the method comprising supplying the composition to a reactor and optionally heating the composition at a temperature of 40°C to 150°C in the presence of chlorosulfonyl isocyanate and chlorosulfonic acid.

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