MXPA96001073A - Reagent and procedure for the synthesis of oxisulfurated organic derivatives and fluora - Google Patents

Abstract

The present invention relates to a reagent useful for the synthesis of organic oxysulfurized and fluorinated derivatives by the reaction with a sulfur acid, mainly sulfur dioxide, characterized in that it comprises: a) a fluorocarboxylic acid of the formula Ea-CF 2 -COOH, wherein Ea represents an atom or an electro-attractant group, at least partially salified by an organic or mineral cation, and b) a polar aprotic solvent, and because the amount in the liberal protons carried by its various components, including its impurities, is at most equal to half of the initial molar concentration of said fluorocarboxylic acid. This reagent can be put into practice by heating for fluorinated sulphonic or sulphonic forms

Description

REAGENT AND PROCEDURE FOR SYNTHESIS OF OXISULFURATED AND FLUORATE ORGANIC DERIVATIVES FIELD OF THE INVENTION The present invention relates to a process for the preparation of fluoroalkane sulphonic and sulphonic acids and their salts. It refers more particularly to the preparation of polyhalogensulfinic and sulphonic acids, mainly difluoro- or trifluoromethane sulphonic and sulfonic acids.

BACKGROUND OF THE INVENTION Perhalogenoalkane sulphonic acids and, more particularly, trifluoromethane sulphonic acid are used as catalysts or as intermediates in organic synthesis. Initially, the only known process for the manufacture of trifluoromethane sulfonic acid was electrochemical fluorination as described primarily by RD Howels, JD Me Cown in Chemical Reviews, 1977, 77, 69. The method of acid preparation is also known. trifluoromethanesulfinic, described in the European patent published under the number EP-165 135, which consists of putting in the presence of Sulfur dioxide - a metal chosen from zinc, aluminum, manganese, cadmium, magnesium, tin and iron, including nickel and cobalt, in a polar aprotic solvent after adding a trifluoromethyl halide under pressure greater than 10 Pa. This procedure allows to obtain a product in the form of trifluoromethane sulfinate with good yields. The sulfinate obtained is in a medium containing a significant amount of zinc salt. The separation of sulfide to and from other zinc salts poses a problem to the industrial level. On the other hand, this technique, as well as that described in the French application published under number 2 593 808, required the use of perfluoroalkyls bromides which are considered particularly harmful for the atmospheric layers, mainly because of their strong effect of greenhouse and its effect considered harmful to ozone.

DESCRIPTION OF THE INVENTION That is why one of the objects of the pre-sentate invention is to provide a reagent for the preparation of organic oxysulfurized and fluorinated derivatives, by the reaction with a sulfur oxide, which allows the use of products less harmful to the environment than trifluoromethyl bromide, which is not very expensive. Frequently it has been sought to use perfluoroalkyl radicals, in a more general form of trifluoromethyl radicals, the perfluorocarboxylic acids, by carrying out the decomposition reactions aimed at eliminating the carboxylic fragment of such acids by releasing the carbon dioxide. However, the events that had to be obtained were very mitigated and used particularly complicated catalytic systems. The perfluoroalkyl radicals or their equivalents generated by the decomposition of said perfluorocarboxylic acids were also unstable in the reaction medium and required the use of stabilizing agents. The present invention aims to avoid the drawbacks of existing processes by providing a reagent more respectful of the environment and capable of leading to the desired products with satisfactory performance. In the course of the study that has guided the present invention, it has been shown that it is possible to generate the fluoroalkyl radicals from a fluorocarboxylic acid, without catalyst and without an agent capable of stabilizing the various intermediates considered, obtained during the decomposition of different perfluorocarboxylic acids. It is evident that, in order to obtain a decarboxylation of fluorocarboxylic acids, two conditions are essential; one is the choice of solvent, and the other is the amount of impurities in the mixture constituting the reagent according to the present invention. Thus, the absolutely critical function of the quantity of labile hydrogen atoms in the system could be demonstrated"or, more exactly, of releasable protons, which must be less than the amount of fluorinated groups liberated by the decomposition of fluorocarbo-xylic acids, by a labile hydrogen atom or a releasable proton, is meant a hydrogen atom that is susceptible to In practice, protons of acidic functions that have a pKa of less than about 20 (for "approximately") are reacted by stressing that the number 20 does not present more than a significant figure.) The objectives cited above, and others that will appear later, are thus achieved through of a reagent useful for the synthesis of organic oxysulfurized and fluorinated derivatives by the reaction with a sulfur oxide, mainly with sulfur dioxide, characterized in that it comprises: a) a fluorocarboxylic acid of the formula Ea-CF_-COOH wherein Ea is an atom or an electro-attractant group, at least partially salified by an organic or mineral cation, and b) a polar aprotic solvent; and because the amount of releasable protons carried by their various components, including their impurities, is at most equal to half the initial molar concentration of said fluorocarboxylic acid. The more the amount of releasable protons will be reduced, there will be less risk of parasitic reaction and the better the performance. Thus, it is preferable that, in the reactant, the proportion of labile hydrogen atoms be at most equal to 10%, preferably 1% (in moles), relative to the initial amount of said fluorocarboxylic acid. The main impurity, carrier of labile hydrogen atoms, is in general water that is capable of releasing up to two protons per molecule.

In general, it is preferable to use reagents and solvents carefully dehydrated, so that the weight ratio in water of the reagent is at most equal to 1 to 1000, in relation to the total mass of the reagent. Depending on the set of reaction conditions, such amounts of water may be satisfactory, but in some cases, it may be interesting to operate at lower levels, for example of the order of 1 to 10 000. However, it is not necessarily essential to eliminate the All water and a water / fluorocarboxylic acid molar ratio of less than 10% can be tolerated. On the other hand, it has been shown that other elements, namely the transition elements that have two stable valence states, such as copper, may not be phantom, they may even be harmful to the invention. Although this reagent according to the invention does not need a catalyst, such metal elements can be present as impurities provided mainly by the solvent. Thus, it is preferable that the molar amount of these elements is less than 1000, advantageously at 100, preferably at 10 ppm relative to the initial amount in said fluorocarboxylic acid. To favor some substrates and favor some types of reaction, it had also been recommended several times to use elements of column VIII of the periodic classification of elements with per-fluoroacetic acid. This has been revealed without interest for the objective reaction, subsequently. For this reason, taking into account the high price of these compounds, it is preferable to use reagents that do not contain metals from column VIII, mainly metals from the platinum mine which is the group consisting of platinum, osmium, iridium, palladium / of rhodium and ruthenium. In the present description, reference is made to the supplement of the bulletin of the Chemical Society of France number 1, January 1966, in which a periodic classification of the elements has been published. Thus, it is preferable that the amount of metals in the platinum mine, including metals in column VIII, be less than 100 ppm, advantageously at 10 ppm, preferably at 1 ppm. These values are understood in relation to the starting fluorocarboxylic acid and are expressed in moles. In a more general and more empirical way, it can be pointed out that these two categories of metals, knowing the transition elements of two valence states and the elements of column VIII, should be present in the reactant at a level of overall concentration at the most equal to 1000 molar ppm, preferably at 10 molar ppm. It will be noted that the different metals present at such a level of global concentration are in extremely small amounts, and in this respect, they do not play any catalytic role. Their presence does not improve the kinetics of the reaction, even when they are present in too large quantities. The utilization, in addition to the components of the above-mentioned reagents, of alkaline fluoride or of quaternary ammonium fluoride, usually present in the reactive systems using the fluorinated carboxylates, have not proved disastrous, but they have proved of little interest, because that they produce saline effluents that are difficult to treat. However, it is noted that the presence of fluorides in the medium has tended to limit, at the same time, the transformation of the starting fluorocarboxylic acid and the decomposition of the product of arrival. Overall, this effect is shown rather positive, due to a better acid transformation performance fluorocarboxylic acid in the desired product, ie, a good selectivity of the reaction. This effect tends to be all the more important that the counter-cation of fluoride is bulky. The cations that can be considered are the cations of alkali metals of higher rank than that of sodium, in particular potassium or cesium, or the ions of the "onium" type, namely the cations formed by the elements of the columns VB and VI B (as defined in the table of periodic classification of the elements published in the bulletin supplement of the Chemical Society of France in January 1966), with 4 -or 3 hydrocarbon chains. Among the oniums derived from elements of the V B column, the preferred reactants are the tetraalkyl or tetraaryl ammonium or phosphonium. The hydrocarbon group advantageously comprises from 4 to 12 carbon atoms, preferably from 4 to 8 carbon atoms. The onios derived from column VI B are preferably derived from elements of atomic number greater than that of the oxygen. In spite of the drawbacks that have been mentioned above, the amount or proportion of fluoride ions is a parameter that can be considered. However, it may be preferable to limit this amount, in particular the initial amount, in order to facilitate the final treatment of the reaction medium. Thus, it is advantageous if the quantity or proportion of fluoride, which is qualified as ionic, that is to say, capable of being ionized in the medium that polarizes the reagent, is at most equal to the initial molar concentration in said fluorocarboxylic acid salt, advantageously half, preferably the fourth. As mentioned above, the solvent plays an important role in the present invention and must be aprotic, and advantageously polar, and comprises very few impurities carrying acid hydrogen. It is thus preferred that the usable polar aprotic solvent has a significant dipole moment. Thus, its relative dielectric constant £ is advantageously at least equal to about 5 (position zeros are not considered as significant figures in the present description unless otherwise stated). Preferably £ is less than or equal to 50 and greater than or equal to 5, and is mainly comprised between 30 and 40. It is further preferred that the solvents of the invention are capable of dissolving the cations well, which can be coded by the donor index D of these solvents. It is preferable that the index donor D of these solvents is between 10 and 30. Such donor index corresponds to the? H (enthalpy variation), expressed in kilocalorie per mole, of the association of said polar aprotic solvent with antimony pentochloride. According to the present invention, it is preferable that the reagent does not present hydrogen hydrogen in the polar solvent (s) that he himself uses-; In particular, when the polar character of the solvent (s) is ob- tained by the presence of electroatractive groups, it is desirable that they do not have alpha hydrogen of the electroatractive function. More generally, it is preferable that the pKa corresponding to the first acidification of the solven-te is at least equal to about 20 ("approximately" indicates that only the first number is significant), advantageously at least equal to about 25, preferably between 25 and 35. The acid character can also be expressed by the solvent acceptor A, as defined by Reichardt, "Solvents and solvent effects in Organic Chemistry", 2nd edition, VCH (RFA), 1990, pages 23-24. Advantageously, this acceptor index A is less than 20, in particular less than 18. It is preferable that said acid or acid salt The fluorocarboxylic acid is at least partially, preferably completely, soluble in the medium constituting the reactant. The solvents that give good results can be mainly amide type solvents. Between the amides, amides of a particular nature are also understood, such as tetrasubstituted ureas and monosubstituted lactams. The amides are preferably substituted (disubstituted by the ordinary amides). Mention may be made, for example, of pyrrolidone derivatives, such as N-methylpyrrolidone, or also N, N-dimethylformamide, or N, N-dimethylacetamide. Also advantageous are solvents such as 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) pyrimidinone (DMPU), 1,3-dimethyl-2-imidazolidinone (DMI or DMEU), or the ben-zonitrile. Another particularly interesting category of solvent is constituted by ethers, which are symmetrical or non-symmetrical, whether they are open or not. In the case of the ethers, the different derivatives of glyceryl ethers should be incorporated, such as the different glymes, the diglyme for example. In the fluorocarboxylic acid of the constituent a) of the reagent of the invention, the entity Ea which exerts an electro-attractant effect on the carbon atom difluorinate is preferably chosen among the functional groups whose Hammett constant 0 is at least equal to 0.1. Furthermore, it is preferable that the inductive component of & i C. r is at least equal to 0.2, advantageously at 0.3. In this regard, one will refer to March's work, "Advanced Organic Chemistry", third edition, John Wiley and Son, pages 242 to 250, and mainly in table 4 of this section. More particularly, the electrically active entity Ea can be chosen from halogen atoms, preferably light, mainly chlorine and fluorine atoms. The corresponding fluorocarboxylic acid is a halogenofluoroacetic acid of the formula (1) X-CF- -COOH wherein X is a halogen atom, advantageously light (chlorine or fluorine). Ea can also be advantageously chosen from the nitrile groups (with the risk as a parasitic reaction of an alpha elimination), carbonylated, sulphonated and perfluoroalkylated. Fluorocarboxylic acids of this type that can be used correspond to the formula (2) R-G-CF_-COOH wherein R-G represents a nitrile group or G represents ^^ C = O, S = 0, or - ( CF,) - where n is greater than or equal to 1, and R represents an indifferent organic or mineral residue, of preferably an organic radical such as aryl, alkyl, or aralkyl, optionally substituted. R may also represent a solid mineral to organic support, such as a resin. In the case where G represents a per-fluoroalkylene group - (CF2) is advantageously between 1 and 10, preferably between 1 and 5. In this case too, R can also represent a halogen atom, mainly fluorine Generally, except in the case where the fluorocarboxylic acid is a polymer, the total number of carbon atoms of the fluorocarboxylic acid does not advantageously exceed 50. The countercations capable of forming a salt with said fluorocarboxylic acid are Advantageously bulky, the alkali metal salts are advantageously used, advantageously wherein said metal is chosen from sodium, potassium, rubidium, cesium and francium, preferably the metal is of a period whose range is at least equal to It is also possible to improve the reaction using cations that are either naturally voluminous. as quaternary ammonium cations or quaternary p-phonium, or becoming bulky by the addition of chelating agents or preferably transformation agents, such as for example the capped ethers or the derivatives that are both aminated and oxygenated. The salts of perfluorocarboxylic acids can be advantageously used, such as the trifluoroacetate, perfluoropropionate and perfluorobutyrate of alkali metal, mainly of potassium *. "It is observed that the use of inhibitors of the type crowned ethers, accelerates markedly The transformation of the starting fluorocarboxylic acid may be used advantageously in an amount of 5 to 100 mol%, mainly 5 to 25 mol%, based on the initial amount or proportion in fluorocarboxylic acid. , some associations with the other members or elements of the reaction medium, mainly some solvents, may have a less favorable effect as regards the stability of the arrival product, and they will not be considered as advantageous. present invention is to provide a process for the synthesis of organo-oxysulfurized and fluorinated organic derivatives, mainly of you go out of sulphonic or sulphonic acids, which utilize the reagent according to the present invention. This object is achieved by: a) contacting said reagent with a sulfur oxide and b) heating the resulting mixture at a temperature comprised between 100 ° C and 200 ° C, preferably between 120 and 150 ° C, and this, for a duration of at least one half hour, advantageously of at least one hour, and at most one day, advantageously less than 20 hours. The presence or contact of the reaction with the substrate can be progressive or not, in particular it can be achieved that one of the two is at the appropriate temperature to introduce the other, this introduction can be progressive or not. The reagent can be cast into the substrate or reciprocally.The fluorocarboxylate and the substrate can be simultaneously and progressively introduced into the solvent.When said oxide is sulfur dioxide, the mixture resulting from step a ) can comprise two phases in equilibrium and thus comprise a liquid phase, in which a part of at least said acid and sulfur dioxide are dissolved in said solvent, in equilibrium with a gas phase containing sulfur dioxide. As regards the relative amounts of said initial fluorocarboxylic acid, and of sulfur oxide, preferably bioxide, it is preferable that the ratio be between 1 and 10, advantageously about two, sulfur atoms per molecule of fluorocarboxylic acid. It has been found that, all things are the same on the other hand, the performance in the objective organic derivative depends on the degree of progress of the reaction and that a very reduced final yield can be obtained despite a significant conversion of reagents Without waiting to be linked to any scientific theory, it seems that everything happens as if he himself had a kinetic of formation and a kinetic of degradation of the obtained products. In order to avoid a very important degradation of the final product, and thus ensure a good selectivity of the reaction, it is preferable not to seek to completely convert the starting fluorocarboxylic acid. The progress or development of the reaction can be controlled by the rate of transformation (TT) of the acid which is the molar ratio of the amount of acid disappeared in the amount of initial acid in the reaction medium, this rate is calculated easily after the dosage of the remaining acid in the medium. Advantageously, the reaction is conducted only to obtain a conversion rate of 40 to 80%, preferably 50 to 70%, then the reaction products will be separated. It is thus possible to achieve a selectivity of the order of 80% expressed by the molar ratio of the desired product / transformed fluorocarboxylic acid. To be placed in the optimum reaction conditions, it is possible to limit the rate of transformation by reacting both the nature of the solvent and the presence of additives which tend to limit this transformation, such as, for example, reacting at the same time in the duration of the reaction. the fluoride ions. The reaction kinetics also depends on reaction members or elements (fluorocarboxylic acid and sulfur oxide) and the appropriate reaction time can easily be adapted in case of this kinetics. In the case of sulfur dioxide, a duration of the reaction of 2 to 7 hours may be sufficient, depending on the reagent used. Once the desired transformation rate has been reached, the reaction mixture can be treated in known manner with it to separate the obtained product. the starting products can be recirculated to produce a supplemental amount of the objective organic derivative. When said sulfur oxide is sulfur dioxide, the product obtained by heating the reagent is a sulfinic acid or a salt of sulphonic acid whose counter-ion is that of the starting fluorocarboxylic acid salt. To separate the product from the reaction, an advantageous possibility consists in carrying out a supplementary transformation into a relatively volatile and easily distillable derivative. Thus, for example, in the course of the reaction between SO- and trifluoroacetic acid CF-CO-H or its salts, trifluoromethylsulfinic acid CF-.SO-H or its salts obtained can easily be converted in the presence of chlorine Cl_ into the acid chloride corresponding to an oxidation, namely CF-SO-Cl (this reaction is general for the acids * used and mainly for the perfluoroalcansulfinic acids Rf SO_H). This reaction, which does not affect the trifluoroacetic acid-based reagent, advantageously allows CF-SO-Cl to be separated by distillation leaving the mineral chlorides as well as the intact tri-fluoromethylation reagent in the reaction medium, which then it can be reused to continue the reaction with the sulfur oxide. This reaction is common to the different fluorinated sulfuric acids obtainable according to the invention. This example can be generalized for the separation of any types of fluorinated oxysulfurized organic derivatives obtained according to the invention, capable of being transformed by an appropriate reaction into more volatile products.

In order to pass from the sulfinic acid to the corresponding sulphonic acid, it is advisable to subject the reaction product or the purified reaction product to oxidation, which is known, mainly by means of hydrogen peroxide or sodium hypochlorite. A process for the purification of sodium trifluoroethyl sulphinate, and of sulfonate oxidation, applicable according to the invention, is described in the European patent application published under the number EP-A-0 396 458. The salts of sulphonic or sulphonic acids thus, they can be converted into the free acids corresponding to the acid medium. The reaction products, salts or free acids, can be easily isolated and used in the subsequent stages of organic synthesis. For example, sulfinyl chlorides obtained from fluorinated sulphonic acids can be valorised prepared according to the invention.

The following non-limiting examples illustrate the invention. The results presented in the examples are expressed in terms of three dimensions or parameters which are defined later: the rate of transformation of a reagent R (TTR) is the proportion of the amount (molar) of R de-saparecida in the course of a reaction in the amount of initial R; the actual production yield of a product P from a reagent R (RRP) is the ratio of the amount of P produced in the initial R amount; the transformation yield of R in P (RTP) which is the proportion of the amount of P produced in the quantity of R disappeared.

EXAMPLE 1 Preparation of trifluoromethyl sulfinic acid.

In a 100 ml Hastalloy reactor, stirred by a turbine, introduce 42 g of the N-methyl-pyrrolidone (NMP), then 5.32 g (35 mmol) of trifluoroacetate. of potassium and finally 4.9 g (76 mmoles) of gaseous sulfur dioxide by borbolleo in the liquid. Sulfur dioxide is fully solubilized with NMP. The molar ratio of sulfur dioxide to potassium tri-fluoroacetate is 2.1. The amount or proportion of water of the reactive mixture is 0.1% by weight relative to the weight of the mixture, that is, a ratio or molar ratio of the water with the trifluoroacetate of 0.07. The mixture is heated in the closed reactor at a temperature of 140 ° C for 6 hours under stirring. During the course of the reaction, the pressure inside the reactor brought to an ambient temperature rises by 3.5 x 10 Pa in relation to the initial pressure. The reaction medium is then recovered with water and analyzed by HPIC ion chromatography (High Performance Ionic Chromatography) in the separation mode to dose the transformation of potassium trifluoroacetate. The transformation rate (TT) of the starting potassium trifluoroacetate, expressed with the ratio or molar ratio of the amount of trifluoroacetate consumed (transformed) with the initial amount, is 61.7%.

The actual yield (RR), expressed by the molar ratio of the amount of trifluoromethylsulfi-nate formed, under the free or salified form, with the initial amount of trifluoroacetate, is 29.7%. The yield relative to the transformed product (RT), expressed by the molar ratio of the amount of trifluoromethylsulfinate formed, under the free or salified form, with the amount of the transformed trifluoroacetate, is 48.1%. The product is isolated in the form of a potassium salt.

EXAMPLE 2 Example 1 is repeated exactly, except that 8.6 g (35 mmoles) of cesium trifluoroacetate are used in the reagent. The dosage by HPIC allows to calculate that TT is 68.4%, RR is worth 21% and RT is 30.7%. The product is isolated in the form of cesium salt. Cesium trifluoroacetate is of relatively less advantageous use than the potassium salt.

EXAMPLES 3 and 4 Example 1 is repeated exactly, except that N, N-dimethylacetamide (DMAC, £ = 37.8) and N, N-dimethylformamide (DMF, é = 36.7) are used as a solvent, respectively. The progress of the reaction is dosed by HPIC and the results are reported - in table 1, where the solvent used and its donor index D are recalled for each example.

Comparative example 1 Example 1 is repeated exactly with the exception that it is operated only in the presence of an excess of sulfur dioxide without solvent (dielectric constant £ = 14). The results are shown in table 1.

TABLE 1 * SO- serves both solvent and reagent.

Comparative Example 1 demonstrates that the solvent is necessary for the transformation into the desired product.

EXAMPLE 5 This example recapitulates a series of different tests in which different solvents have been tested under conditions close to those of Example 1. Potassium trifluoroacetate (in a weight ratio CF, CO_K / solvent = 0.13) is put in the presence of about 2 molar equivalents of sulfur dioxide (molar ratio SO_ / CF3CO_K from 1.9 to 2.1). The reagent mixture is heated in the closed reactor, stirred at 1000t / min, with an elevation at the temperature of 10 ° C / min up to 140 ° C, for 6 h. The advance or development of the reaction is dosed by HPIC and the results are reported in table 2 where the solvent used is recalled for each test, its dielectric constant e, its donor index DN, its acceptor index AN and the amount of water in the middle.

TABLE 2 Yes fifteen Generally speaking, for low acid solvents (A < 19), yields evolve in the same direction as the dielectric constant £. In this respect, the DMF, the DMAC and the DMPU gave excellent results, those of the NMP are slightly lower. On the contrary, with the DMSO and CH-CN, the results are less good, in spite of the high dielectric constants, and this is to compare their acid character (A = 19.3).

EXAMPLE 6 Example 1 is repeated exactly, except that more carefully dehydrated reactive compounds are used. The amount of water in the reactive mixture is 0.05% by weight relative to the weight of the mixture, that is, a molar ratio of the water with the trifluoroacetate of 0.04. The results of the test, dosed by HPIC, are reported in table 3. The results of example 1 are also remembered in this table.

Comparative Example 2 (to compare examples 1 and 6) Contrary to the previous example, example 1 is repeated with more hydrated reagents, so that the amount or proportion of releasable protons is outside the limits of the invention. The amount of water in the reaction mixture is 0.8% by weight relative to the weight of the mixture. The molar ratio of the water with the trifluoroacetate is 0.6, the ratio of the amount of water-borne protons provided by the water to the amount of trifluoroacetate is thus 1.2. The results of the test, dosed by HPIC, are reported in table 3.

EXAMPLE 7 Example 6 is repeated exactly, except that the DMAC is used as the solvent. The results of the test are shown in Table 3, where the results of Example 3 are also reported.

TABLE 3 Examples 6 and 7 show that a reduced amount of water dramatically improves the transformation efficiency. Comparative example 2 confirms that an amount of protons liberable from the reactive system in excess of half the amount of trifluoroacetic acid salt is harmful to the formation reaction of trifluoromethylsulfinate.

EXAMPLE 8 This example recapitulates a series of tests that also show the importance of the amount of water in the reaction of sulfur dioxide with potassium trifluoroacetate in conditions close to those of example 1. Even in the NMP, potassium trifluoroacetate (in a weight ratio with respect to the solvent CF-C02K / NMP = 0.13) is placed in the presence of approximately 2 molar equivalents of sulfur dioxide (molar ratio SO- / CF3CO-K from 1.9 to 2.1). The mixture is heated in the closed reactor, stirred at 1000 t / min with a temperature rise of 10 ° C / min up to 140 ° C for 6 hours. The results are summarized in table 4 below: TABLE 4 In these tests, the formation of fluoride ions is observed with an RR yield of approximately 25%. There is a clear improvement in performance and selectivity, going from conditions a) to the conditions b). An optimum appears in the range of 2 to 8%, around 4%.

EXAMPLE 9 This example recapitulates a series of tests in which fluoride ions have been introduced into the reaction medium from the beginning of the reaction. The test 9.a was carried out in the NMP following the protocol of example 5, test d, and adding 1 mole of potassium fluoride per mole of starting trifluorocarboxylic acid. The 9.b-d tests have been carried out in the DMF following the protocol of test 5.c and adding different amounts of KF. The tests 9.e, f, g have been carried out in the same solvents using this time the cesium fluoride. The results are gathered in the following table 5: ) u. fifteen In all cases, the transformation rate of CF-CO-K is limited by the presence of fluorides and an increase in selectivity and, in general, in yields is observed.

EXAMPLE 10 In this example, we compare the results obtained in the absence and in the presence of a co-rounded ether sequestrant, the 18th crown 6. The different tests have been carried out in various solvents, following the protocol of example 6. The results are summarized in the next table.

O < < HEY WHAT In all cases, the transformation of the starting product is favored, with no notable incidence, however, in the decomposition into fluorides. This is even diminished with the NMP solvent. In trials b, c and d, the actual performance in CF-SO-K is much better when the inhibitor is used.

EXAMPLE 11 This example presents a kinetic study of the reaction of test 5.d. The transformation rate of trifluoroacetate, the actual yield and the transformation yield of trifluoromethylsulfinate, as well as the actual yield of fluoride ions, have been determined by reaction times ranging from 2 to 9h 30 min. The results are summarized in table 7 below.

TABLE A maximum of yield and selectivity is observed at about 4 hours of reaction. When the duration of the reaction increases, the yield decreases and an increasing number of fluoride ions appear, a sign of degradation of the trifluoromethyl groups in the medium.

Example 12: Preparation of pentafluoroethylsulfinic acid.

In the same reactor as that of Example 1, 40 g of NMP, 7.07 g of anhydrous C-F-COOK (35 mmoles) then 4.9 g (76 mmoles) of SO- are introduced. The mixture is heated in the closed reactor at a temperature of 140 ° C for 6 hours.

The pressure variation inside the reactor between the start and end of the reaction is 3.5 bar. The reaction medium is recovered with water then the mixture is metered by 19 F NMR. The transformation rate TT is 85%, the reaction yield RR is 73% and the transformation yield RT is 86.2,%. The product is isolated in the form of potassium salt.

EXAMPLE 13: Preparation of heptafluo-ropropylsulfinic acid.

In the same reactor as that of Example 1, 40 g of NMP, 8.8 g of anhydrous C-.F-COOK (35 mmol) are introduced then 4.9 g (76 mmol) of SO-, The mixture is heated in the closed reactor at a temperature of 140 ° C for 1 h 30. The pressure variation inside the reactor between the start and end of the reaction is 4.5 bar. The reaction medium is recovered with water then the mixture is metered by 19 F NMR. The TT transformation rate is 85%, the RR reaction yield is 70% and the yield of RT transformation is 82%. The product is isolated in the form of potassium salt.

EXAMPLE 14: Preparation of trifluoro-romethylsulfinyl chloride The potassium trifluoromethylsulphinate is prepared under the conditions of example 4. The DMF is removed from the reaction mixture by distillation under vacuum at a temperature not exceeding 55-60 ° C. The distillation residue is recovered with the acetonitrile then filtered. The filter is distilled to remove the solvent and the potassium trifluoromethyl sulfinate is isolated with a purification efficiency of 96% relative to the crude or crude reaction mixture., dosed by ion chromatography. The product resulting from this operation is recovered with toluene and thionyl chloride SO Cl_ is added in a stoichiometric amount relative to trifluoromethylsulfinate. The trifluoro-ethyl-sulfinyl chloride (CF-SOC1) is obtained with a yield of 65% EXAMPLE 15: Preparation of tri-fluoromethylsulfonyl chloride.

The potassium trifluoromethansulinate is prepared under the conditions of Example 4. The DMF is removed from the reaction mixture by distillation under vacuum at a temperature not exceeding 60 ° C. The distillation residue is recovered with water. The chlorine is bubbled into the aqueous solution in a stoichiometric amount relative to the trifluoromethylsulfinate present in the medium. The reaction temperature is 0 ° C - 5 ° C. By decanting the lower layer, the trifluoromethylsulfonyl chloride was isolated. This unrefined product is distilled, eb: 28-31 ° C. The yield is 80% in relation to the tri-fluoromethylsulfinate present in the medium.

EXAMPLE 16 Preparation of trifluoromethylsulfonic acid (triflic acid).

The aqueous solution obtained in the same conditions as those described in example 15, is oxidized with hydrogen peroxide of 30 volumes, an excess of 10% of hydrogen peroxide in relation to potassium trifluoromethylsulfinate is necessary. The reaction temperature is 5 ° C. After distillation of the water and drying, the salts obtained are acidified with 100% sulfinic acid. Triflic acid is thus separated from trifluoroacetic acid.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property

Claims (20)

1. A reagent useful for the synthesis of organic oxysulfurized and fluorinated derivatives by the reaction with a sulfur oxide, mainly sulfur dioxide, characterized in that it comprises: a) a fluorocarboxylic acid of the formula Ea-CF_-COOH, where Ea represents an atom or an electro-attractant group, at least partially salified by an organic or mineral cation, and b) a polar aprotic solvent; and because the amount of releasable protons transported by its various components, including its impurities, is at most equal to half the initial molar concentration of said fluorocarboxylic acid.

2. The reagent according to claim 1, characterized in that said amount of pro-tones is at most equal to 10% of the molar concentration in said fluorocarboxylic acid.

3. The reagent according to claim 1 or 2, characterized in that its amount or proportion in water is less than 10% of the concentration molar of said fluorocarboxylic acid.

4. The reagent according to any of the preceding claims, characterized in that its amount in transition elements having at least two stable valence conditions or conditions, is less than 1000 molar ppm, relative to said fluorocarboxylic acid.

5. The reagent according to any of the preceding claims, characterized in that its amount or proportion in elements of column VIII of the periodic classification of the elements, is less than 100 molar ppm, relative to said fluorocarboxylic acid.

6. The reagent according to any of the preceding claims, characterized in that its amount or proportion, expressed in equivalents, of ionic fluoride, is at most equal to the molar concentration of said fluorocarboxylic acid.

7. The reagent according to any of the preceding claims, characterized in that the donor index of said aprotic solvent polar, is between 10 and 30.

8. The reagent according to any of the preceding claims, characterized in that the acceptor index of said solvent is less than 20.

9. The conformance reagent according to any of the preceding claims, characterized in that the pKa corresponding to the first acidification of said solvent is at least equal to 20.

10. The reagent according to any of the preceding claims, characterized in that it itself comprises a crowned ether which inhibits or functions as a complexing agent.

11. The reagent according to any of the preceding claims, characterized in that said atom or electro-attractant group is chosen from the electro-attractant groups of which the constant of Hammet is at least equal to 0.1. P

12. The reagent according to any of the preceding claims, characterized in that said acid is chosen from the compounds of the formula (1) X-CF_-COOH, wherein X represents a halogen atom, and the compounds of the formula (2) R-G-CF-COOH, wherein R- G represents a ni-trile group or G represents Je = 0, ^. S = 0 or - (CF-) - with n greater than or equal to 1 and R is an indifferent organic or mineral residue.

13. The reagent according to any of the preceding claims, characterized in that said at least partially salified fluorocarboxylic acid is completely soluble in the reactive medium.

14. The reagent according to any of the preceding claims, characterized in that said acid is salified by an alkali metal cation chosen from sodium, potassium, rubidium, cesium and francium, or by a quaternary ammonium.

15. The reagent according to any of the preceding claims, characterized in that the solvent is chosen from amides disubstituted in N, including tetrasubstituted ureas and monosubstituted lactams, and cyclic ethers or not, and benzonitrile.

16. A process for the synthesis of a salt of an organic compound at the same time fluorinated and oxysulphurized, characterized in that it comprises the steps: a) of contacting a reagent according to any of claims 1 to 15, with a sulfur oxide; and b) heating the resulting mixture to a temperature comprised between 100 and 200 ° C, for a duration comprised between 1/2 hour and 20 hours.

17. The process according to claim 16, characterized in that said sulfur oxide is sulfur dioxide.

18. The process according to claim 17, characterized in that the liquid mixture of step a) is in equilibrium with a gas phase containing sulfur dioxide.

19. The process according to any of claims 16 to 18, characterized in that the reaction products are separated when the transformation rate of fluorocarboxylic acid It is 40 to 80%.

20. The method according to claim 18, characterized in that it comprises a step c) of oxidation of the salt of sulfinic acid obtained in step b), by contacting the product of stage b) with an oxidation reagent,