USOO6521199B2 (12) United States Patent (10) Patent No.: US 6,521,199 B2 Braun et al. (45) Date of Patent: Feb. 18, 2003

(54) REGENERATION OF ONIUM FLUORIDE-HF 5,728.884. A * 3/1998 Hahn et al...... 564/468 ADDUCTS 5,847,245 A 12/1998 Franz et al...... 570/175 5,969,199 A 10/1999 Franz et al...... 570/175 (75) Inventors: Max Braun, Wedemark (DE); Stefan Palsherm, Barsinghausen (DE) FOREIGN PATENT DOCUMENTS DE 2823969 12/1979 (73) Assignee: Solvay Fluor und Derivate GmbH, DE 19942374 5/2000 Hannover (DE) DK 2442883 3/1976 DK 2460821 6/1976 (*) Notice: Subject to any disclaimer, the term of this EP OOO5810 12/1979 patent is extended or adjusted under 35 EP O901999 3/1999 WO OO/32549 6/2000 U.S.C. 154(b) by 0 days. WO O1/17931 3/2001 (21) Appl. No.: 10/086,635 OTHER PUBLICATIONS (22) Filed: Mar. 4, 2002 Jens Chr. Norrild, et al., “A Facile and Efficient Synthesis of (65) Prior Publication Data (+)- and (-)-allo- Muscarine and Analogs”, Short Papers, Mar. 14, 1997. US 2002/0173681 A1 Nov. 21, 2002 R. F. Weinland, et al., “Over hydraulic fluorides of some, partially very weak, organic Basen Agrikulturchemisches Related U.S. Application Data Laboratorium, Oct. 1908. (63) Continuation of application No. PCT/EP00/08396, filed on Wolski, et al., Journal of American Chemistry Society, vol. Aug. 29, 2000. 72, 1950, pp. 995-997. Padma, et al., Indian Journal of Chemistry, vol. 20A, 1981, (30) Foreign Application Priority Data pp. 777-779. Sep. 4, 1999 (DE) ...... 19942 373 Franz, Journal of Fluorine Chemistry, vol. 15, 1980, pp. Nov. 24, 1999 (DE) ...... 19956 365 423-434. (51) Int. Cl." ...... C01B 7/19; CO1B 7/01; Prakash, et al., Indian Journal of Chemistry, vol. 20, 1981, B01J 38/62; B01J 20/34; CO7C 17/00 pp. 195-197. (52) U.S. Cl...... 423/483; 423/486; 423/507; * cited by examiner 502/28: 502/36; 570/163; 570/164; 570/165; 570/170 Primary Examiner Wayne A. Langel (58) Field of Search ...... 423/469, 481, ASSistant Examiner Jonas N. Strickland 423/483, 486,507; 585/904; 502/28,36; (74) Attorney, Agent, or Firm-Crowell & Moring LLP 570/123, 134, 170, 163-165 (57) ABSTRACT (56) References Cited Hydrogen fluoride adducts and ammonium fluorides are U.S. PATENT DOCUMENTS used for fluorinating acid chlorides and halocarbon com pounds Such as chloroalkanes or chloronated ethers. The 4,003,984 A 1/1977 Jones et al...... 423/168 used adducts can be regenerated and then reused in the 4,372,938 A 2/1983 Oda et al...... 423/469 fluorination reactions. 4,734,526 A * 3/1988 Albert et al...... 564/282 5,399,795 A * 3/1995 Franz et al...... 570/165 5,498,807 A * 3/1996 Schach et al...... 570/127 13 Claims, No Drawings US 6,521,199 B2 1 2 REGENERATION OF ONUM FLUORDE-HF elevated temperature ranging from 80 to 120° C., for ADDUCTS example. The HCl or HBr that is liberated can be removed from the gas phase after the autoclave is opened. AS an CROSS REFERENCE TO RELATED example, inert gas can be passed through the autoclave to APPLICATIONS remove the gas phase. It has been shown to be advantageous if Substantially all This application is a continuation of international patent the HF for the fluorination is not consumed during the application no. PCT/EP00/08396, filed Aug. 29, 2000, des fluorination reaction. Although regeneration can be carried ignating the United States of America, the entire disclosure out even if the adduct has been essentially completely of which is incorporated herein by reference. Priority is converted to ammonium chloride or onium chloride, or to claimed based on Federal Republic of Germany application the corresponding bromide, the regeneration is easier to nos. DE 19942 373.3, filed Sept. 4, 1999, and DE 19956 perform when the ratio of amine to HF does not fall below 365.9, filed Nov. 24, 1999. 1 during the fluorination reaction. Of course, the ratio of amine to hydrogen fluoride may be BACKGROUND OF THE INVENTION adjusted in the regenerated product. For many applications 15 The invention relates to a method for regenerating spent it is desirable for the ratio of amine to hydrogen fluoride in ammonium fluoride-HF adducts. Adducts of ammonium the adduct to lie between 1:1.1 and 1:3.5, preferably between fluorides and HF can be used as fluorination reagents. 1:2 and 1:3. This can be achieved, for example, by removing European patent application no. EP-A901,999, for example, the exceSS hydrogen fluoride in the regenerated product by describes the production of sevoflurane from the corre heating or distillation. sponding fluorinated ether, using HF and an amine. The According to U.S. Pat. No. 4,472,938, it is preferred to work-up is performed with the addition of water, with the used ammonium fluoride-HF adducts based on nitrogen result that the onium fluoride-HF adduct is destroyed. containing aromatic compounds, Such as pyridinium U.S. Pat. No. 4,372,938 describes the production of SF fluoride-HF adducts, in the production of Sulfur tetrafluo using ammonium fluoride adducts. The spent onium 25 ride. In the regeneration method without addition of acid fluoride-HF adducts are regenerated by contacting with according to the present invention, an embodiment provides hydrogen fluoride and are reused in the production of SF. for the use of spent trialkylammonium fluoride-HF adducts The amines used are nitrogen-containing, heterocyclic aro or HF adducts of cyclic Saturated amines. Such compounds matic compounds. are advantageously used in the regeneration method, in that it has been determined that spent trimethylammonium SUMMARY OF THE INVENTION fluoride-HF or triethylammonium fluoride-HF adducts, and thus adducts of amines containing short alkyl chains, readily The object of the present invention is to provide an liberate HCl during regeneration. Spent trialkylammonium improved regeneration method. fluoride-HF adducts containing alkyl groups that have at It is also an object of the invention to provide a regener least three carbon atoms are leSS prone to form Solids. ated NH or amine-HF adduct product. 35 Naturally, this is an advantage for regeneration without the These and other objects are achieved by providing an addition of acid. In addition, spent HF adducts of amines in improved process for producing fluorine-containing com which the nitrogen is contained in a Saturated 5- or pounds from chlorine-containing or bromine-containing 6-member ring System and which also contain heteroatoms compounds by chlorine-fluorine exchange or bromine Such as oxygen-adducts of piperidine or pyrrolidine, for fluorine exchange using an onium fluorid-HF adduct as a 40 example-can be regenerated in this manner. reagent or catalyst, in which spent onium fluoride-HF adduct When acid is not added, the regeneration of spent is regenerated using HF in the presence of a liquid carboxy trimethylamine-HF adducts, triethylamine-HF adducts, lic acid; or a spent trialkly ammonium fluoride-HF adduct or tripropylamine-HF adducts, and tributylamin-HF adducts is a spent HF adduct of a cyclic Saturated amine is regenerated 45 especially preferred. using HF. In accordance with one variant of the process of the According to the inventive method for producing invention, the spent adducts are regenerated by the addition fluorine-containing compounds from chlorine-containing or of a liquid carboxylic acid (this term also includes dicar bromine-containing compounds by chlorine-fluorine boxylic acids and tricarboxylic acids). Carboxylic acids, eXchange or bromine-fluorine exchange using onium 50 especially those containing a total of 2 to 4 carbon atoms, are fluoride-HF adducts as reagent or catalyst, spent onium preferably Substituted by halogen atoms, in particular fluo fluoride-HF adducts are regenerated continuously or batch rine atoms. Trifluoroacetic acid is especially preferred as an wise using HF in the presence of a liquid carboxylic acid, additive. and/or spent trialklyammonium fluoride-HF adducts or Adducts containing short-chain alkyl groups have a ten spent HF adducts of cyclic Saturated amines are regenerated 55 dency to form Solids; this can be counteracted by using a using HF. liquid carboxylic acid, particularly trifluoroacetic acid. For AS used herein, the term "spent’ means that the ratio of spent adducts of amines containing long-chain alkyl groups, amine to HF has become unacceptably high and/or the HCl it is necessary to expel the contained HCl when the operation or HBr content has become unacceptably high. In the involves addition of a carboxylic acid. It is often sufficient regeneration, the content of HCl (or HBr) in particular is 60 to add up to 10 mol % of the acid, relative to the spent reduced to an acceptable level-for example, to less than 1 onium-HF adduct calculated as 100 mol%. Of course, even mole HCl per mole amine or NH. In this respect, the HF more acid may be added, up to 20 mol % or more, for content can be brought to the desired level by the addition, example. 80 mol % is regarded as the upper limit, Since Side evaporation, or admixture of adducts with Suitable concen reactions may occur when more than 80 mol % acid is trations. 65 added. It is advantageous to carry out the regeneration in an According to a very particularly preferred embodiment, autoclave or pressurized vessel with the addition of HF at an spent trialkylammonium fluoride-HF adducts, independent US 6,521,199 B2 3 4 of the length of the alkyl groups on the nitrogen, are demonstrate that not only HF adducts with varying HCl regenerated by adding a liquid carboxylic acid, preferably content, but also even pure hydrogen chloride may be trifluoroacetic acid. The reduced tendency toward formation regenerated. A complete regeneration in the Sense that HCl of Solids and the easy expulsion of HCl gas are advanta is completely eliminated is not necessary, but it is possible. geous. Working examples show that also HF adducts with residual The method according to the invention with the addition HCl content can in fact be used as a fluorination catalyst or of acid can generally be used to regenerate HF adducts of fluorination agent. ammonia and amines. These amines may be primary, Secondary, or tertiary amines. The Substituents are prefer The invention also relates to a regenerated product cor ably linear or branched alkyl groups containing 1 to 12 responding to the formula NH-x(1.1-9) HFx(0.001-1) HCl carbon atoms. Adducts of cyclic amines Such as pyrrolidine, or aminex(1.1-9) HFx(0.001-1) HC1. A product containing N-methylpyrrolidine, or piperidine may be used as well. In 1.1 to 3 HF and 0.001 to 0.5 HCl is preferred. “Amine” addition, amines with aromatic Substituents Such as aniline, Stands for NR, where R=C to C alkyl groups. or amines containing nitrogen in an aromatic ring System Such as pyridine, may be regenerated. The regeneration EXAMPLE 1. method is particularly well Suited for HF adducts of the 15 aforementioned cyclic or aromatic amines as well as for Recycling of NBux1.7 HCl to NBu3XY HF using little Secondary and tertiary amines, especially when these Sec HF ondary and tertiary amines are Substituted with 1 to 5, preferably 2 to 4 carbon atoms per Substituent. Methyl, 1OO C. ethyl, n-propyl, i-propyl, n-butyl, and i-butyl are preferred Tributylamine x 1.7 HCI+|HF - Tributylamine x Y HF-Z HCI Substituents. The method according to the invention allows the reuse of Charge spent HF adducts of ammonia and amines from fluorination reactions. The regeneration method according to the inven tion may be used to regenerate spent adducts from the 25 production of, for example, acid fluorides from acid Substance Molar mass Mass in g Mole(s) chlorides, Such as the production of carboxylic acid fluorides Tributylamine x 1.7 HCl 247.34 82.17 O.33 or sulfuryl fluoride from the corresponding chlorides. This HF 2O.O1 50 2.5 applies also to spent adducts originating from the production of fluoroalkyl groups from chloroalkyl groups. Examples of Such reactions include the production of fluoro(hydro) Tributylaminex 1.7 HCl was placed in a laboratory auto carbons, fluorochloro(hydro)carbons, and the analogous clave. After the autoclave was sealed, 50 g HF was added, bromine derivatives from the corresponding chlorine com and the reagents were refluxed for approximately 3 hours at pounds obtained by fluorine-chlorine exchange or fluorine an internal reactor temperature of 100° C. The autoclave was bromine exchange. Another example of Such reactions is the then cooled to an internal reactor temperature of approxi production of fluoroalkyl ethers from the corresponding 35 mately 60 C., and the gas phase at or below atmospheric chloro- or bromoalkyl ethers. preSSure in the autoclave was conducted into a wash bottle containing water. Aparticular embodiment relates to regeneration for multi According to the chloride and fluoride analysis of the Step fluorination methods. For many multi-step fluorination wash bottle, the catalyst remaining in the autoclave had a methods, the conditions for the required reaction medium 40 are different. This is the case for the production of Sulfuryl composition of tributylaminex0.62 HClx7.3 HF. fluoride from sulfuryl chloride, for example. It has been This example shows that even HF adduct that is com found that the Second fluorination Step, that of converting the pletely spent during the formation of hydrochloride can be sulfuryl chlorofluoride to Sulfuryl fluoride, proceeds satis regenerated. It was possible to reuse the regenerated catalyst in the fluorination reaction. The following example shows factorily only if the Sulfuryl chlorofluoride starting com 45 pound is obtained from an adduct of onium fluoride and HF that the HCl content of this product can be reduced even in which the ratio of amine to hydrogen fluoride does not further. exceed 1:3.5. In contrast, the first step involving the fluo EXAMPLE 2 rination of sulfuryl chloride to produce sulfuryl chlorofluo Further reduction of the HCl content in ride is independent of the hydrogen fluoride content in the 50 reaction medium. NBux0.62 HClx7.3 HF to NBuxY HF using an excess of In accordance with one Specific embodiment of the HF invention, it is proposed to Simultaneously perform the 1OO C. regeneration of spent adduct in cases where the hydrogen Tributylamine x 0.62 HCl -- Tributylamine x Y HF-Z HCI fluoride content in the reaction medium is not important. For 55 the production of Sulfuryl fluoride, spent adduct is regener ated in a first reactor using a large excess of HF while the Charge Sulfuryl chloride present in the reactor is simultaneously fluorinated to produce sulfuryl chloride fluoride. In this regard, it is not necessary to convert all the Sulfuryl chloride. 60 After regeneration, the hydrogen fluoride is distilled off to Substance Molar mass Mass in g Mole(s) bring the amine to HF ratio to the desired value of less than Tributylamine x 0.62 HCl x 7.3 HF 354.3 116.83 O.33 1:3.5. The reactor contents can either be further reacted to HF 2O.O1 107 5.35 produce Sulfuryl fluoride or transferred to another reactor to carry out this reaction. 65 To the remaining mixture of tributylaminex0.62 HClx7.3 The following examples are intended to further illustrate HF was added anew 107 g HF, and the reagents were heated the invention without limiting its Scope. The examples overnight at approximately 100° C. The autoclave was then US 6,521,199 B2 S 6 cooled to an internal reactor temperature of approximately EXAMPLES 5 and 6 60° C., and the gas phase at or below atmospheric pressure Variation of the duration of regeneration was conducted into a wash bottle containing water. Calcu lated according to the chloride and fluoride analysis of the EXAMPLE 5 wash bottle, the catalyst remaining in the autoclave had a 1OO C. composition of tributylaminex0.005 HClx4.89 HF. This Triethylaminex HCI+HF - I - Triethylaminex Y HF-HCl composition was confirmed by direct analysis of the remain ing residue in the autoclave, showing that the HCl had been essentially completely driven off. Decomposition products Charge of the amine were not detected. The resulting composition was of excellent quality for use as a fluorination reagent and fluorination catalyst. Substance Molar mass Mass in g Mole(s) EXAMPLE 3 15 Tributylamine x HCl 137.65 1O.OO O.O7 Recycling of NEtx1.0 HCl to NEtxY HF using an excess HF 2O.O1 16.5 O.82 of HF Procedure 1OO C. Triethylaminex HCl+HF -- Triethylamine x Y HF-Z HCI Triethylamine hydrochloride was placed in a laboratory autoclave which was then sealed. HF was then added, and the reagents were heated for 1/4 hours at a reactor tempera Charge ture of approximately 100° C. (the autoclave was preheated for 15 minutes). The gas phase was then discharged into a Stationary oil bath over a period of 15 minutes and analyzed (sample 1). The reactor contents (18.07 g) were transferred Substance Molar mass Mass in g Mole(s) 25 to a PFA flask and flushed with nitrogen for 5 minutes (18.02 Tributylamine x HCl 137.65 37.93 O.28 g). 1.54 g was taken from this Solution and brought to 1 L HF 2O.O1 107.7 5.38 by filling with distilled water, then analyzed by wet chemical methods (sample 2). According to the analytical data the catalyst composition WS Procedure NEtx5.75 HFx0.08 HC1. Triethylamine hydrochloride was placed in a laboratory EXAMPLE 6 autoclave which was then sealed. HF was then added, and the reagents were heated overnight at an internal reactor 1OO C. temperature of 100° C. At a reactor temperature of 100 C., 35 Triethylaminex HCI+HF - Triethylaminex HF-HCl the gas phase at or below atmospheric preSSure was then conducted into a wash bottle filled with water. Calculated Charge according to the chloride and fluoride analysis of the wash bottle, the catalyst remaining in the autoclave had a com position of triethylaminex0.09 HClx5.35 HF. This compo 40 Sition was confirmed by direct analysis of the remaining Substance Molar mass Mass in g Mole(s) residue in the autoclave, showing that the HCl had been Tributylamine x HCl 137.65 10.44 O.08 essentially completely driven off. Decomposition products HF 2O.O1 21.3 1.06 of the amine were not detected. 45 EXAMPLE 4 Procedure Triethylamine hydrochloride was placed in a laboratory Adjustment of the amine/HF ratio of the catalyst mixture autoclave which was then sealed. HF was then added, and of Example 3 to 2.8-Removal 50 the reagents were heated for 30 minutes at a reactor tem perature of approximately 100 C. (the autoclave was pre Procedure heated for 15 minutes). The autoclave was then taken from the oil bath, and the gas phase was discharged over a period The triethylaminex0.09 HClx5.35 HF mixture obtained in of 15 minutes and analyzed (sample 1). The reactor contents Example 3 was introduced into a PFA (perfluoroalkyl) flask 55 (20.96 g) were transferred to a PFA flask and flushed with with frits, and the excess HF was driven off with dry nitrogen for 5 minutes (20.64 g). 1.1 g was taken from this nitrogen. After the weight of the flask had remained constant solution and brought to 1 L by filling with distilled water, for 30 minutes, the flask was placed under a vacuum of 10 then analyzed by ion chromatography (sample 2). According mbar for 10 minutes to completely remove all residual HF. to the analytical data the catalyst composition was According to chloride, fluoride, and amine analysis, the 60 Triethylaminex8.48 HFx0.14 HC1. resulting catalyst had a composition of triethylaminex2.8 The foregoing description and examples have been Set HF. HCl was no longer detectable. This clearly demonstrates forth merely to illustrate the invention and are not intended the recyclability of the catalyst. to be limiting. Since modifications of the described embodi The adjustment of the amine to HF ratio restored the ments incorporating the Spirit and Substance of the invention nucleophilic properties of the adduct. The product was of 65 may occur to perSons skilled in the art, the invention should excellent quality for use as a reagent in the production of be construed broadly to include all variations falling within SOF from SOCl. the Scope of the appended claims and equivalents thereof. US 6,521,199 B2 7 8 What is claimed is: 7. A process according to claim 1, wherein the ratio of 1. In a proceSS for producing fluorine-containing com amine to HF during regeneration is adjusted to a value pounds from chlorine-containing or bromine-containing between 1:1.1 and 1:3.5. compounds by chlorine-fluorine exchange or bromine 8. A process according to claim 1, wherein the spent fluorine exchange using an onium fluoride-HF adduct as a 5 reagent or catalyst, the improvement comprising regenerat onium fluoride-HF adduct originates from production of an ing spent onium fluoride-HF adduct using HF in the pres acid fluoride from a corresponding acid chloride. ence of a liquid carboxylic acid; or regenerating a spent 9. A process according to claim 1, wherein the spent trialklyammonium fluoride-HF adduct or a spent HF adduct onium fluoride-HF adduct originates from the production of of a cyclic Saturated amine using HF. a fluoroalkanes from a chloroalkane. 2. A process according to claim 1, wherein the regener 10. A process according to claim 1, wherein the spent ating is carried out continuously. onium fluoride-HF adduct originates from production of a 3. A process according to claim 1, wherein the regener fluorinated ether from a chlorinated ether. ating is carried out batchwise. 11. A proceSS according to claim 1, wherein the regen 4. A proceSS according to claim 1, wherein a spent onium 15 eration is carried out Simultaneously with a fluorination fluoride-HF adduct which contains HCl or HBr is regenerated, and the HCl or HBr is driven off during the reaction using HF as fluorination reagent. regeneration. 12. A proceSS according to claim 1, wherein the regen 5. A process according to claim 4, wherein the HCl or HBr eration is carried out in the presence of a halogenated is carried off by passing an inert gas through or over the carboxylic acid. spent adduct. 13. A process according to claim 12, wherein the regen 6. A proceSS according to claim 1, wherein the regenera eration is carried out in the presence of trifluoroacetic acid. tion is carried out at a temperature in the range from -20 to 200° C.