Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C313/00—Sulfinic acids; Sulfenic acids; Halides, esters or anhydrides thereof; Amides of sulfinic or sulfenic acids, i.e. compounds having singly-bound oxygen atoms of sulfinic or sulfenic groups replaced by nitrogen atoms, not being part of nitro or nitroso groups
  • C07C313/02—Sulfinic acids; Derivatives thereof
  • C07C313/04—Sulfinic acids; Esters thereof

Definitions

• the subject of the present invention is a method of treatment, in particular of enrichment and purification of salts of a sulfinic acid whose carbon carrying sulfur is perfluorinated. It is known according to the European patent application published under the
• these salts are formed in water-miscible polar aprotic solvents which it is then difficult to remove since their affinity for the salts, and in particular the alkaline or alkaline-earth salts, is such that one finds them. always, even after distillation, significant proportions in reaction products, all the more so since the anions corresponding to perfluoroalkanesulfinic acids are extremely little complexing and very dissociated.
• these solvents strongly complexing alkaline and alkaline-earth salts mention will be made of peralkylated amides and especially DMF (dimethylformamide) which, subsequently, will completely represent the complete class of these aprotic solvents polar hard to remove.
• DMF dimethylformamide
• This acid serves, on the one hand as a precursor of trifluoromethanesulfonic acid and, on the other hand, constitutes the source of a triflinyl radical (CF 3 -SO-) which plays an important role in many derivatives useful in pharmacy and in agriculture.
• CF 3 -SO- triflinyl radical
• one of the aims of the present invention is to provide a process for treating the reaction mixture which makes it possible to obtain triflinic acid, or one of its salts, with good purity.
• Another object of the present invention is to provide a process for treating any perfluorinated sulfinic acid on carbon carrying the sulfinic function, or its salts, so as to obtain a sulfinic derivative of good purity.
• Another object of the present invention is to provide a process of the above type which makes it possible to avoid the presence of polar aprotic solvents, especially when they are water-soluble, in significant proportion in the purified product (that is to say soluble in water at least 50% of the water body).
• Another object of the present invention is to provide a process which makes it possible to avoid the presence of halides in high proportion in the final sulfinic derivative obtained.
• Another object of the present invention is to provide a process of the above type which makes it possible to obtain a level of heavy halides, that is to say in the context of the present invention of bromide or iodine-iodide particularly low ; in particular, to obtain a molar ratio between the sum of heavy halides, on the one hand, and the sulfinyl radical considered, on the other hand, of at most 2%, advantageously at most 1% (the percentages are expressed as percentages of equivalents).
• Said sulfinic acid, or its salts can in particular be: ° either in the form of a crude reaction mixture or after distillation, in particular resulting from the processes described in the European patent applications specified above;
• Said basic organic phase comprises either a weak base, optionally and even advantageously salified, or else the cationic part of a strong base.
• relatively weak bases there may be mentioned amines, imines including intra-cyclic such as pyridines, phosphines and in general all bases whose pKa of the associated acid is less than 12, preferably less than 11. This pKa is advantageously greater than 4.
• this index is advantageously at least equal to 15, advantageously 20.
• neighbor is meant a value which differs only by at most 30% from the reference value.
• R represents an aliphatic radical (the connecting carbon is sp 3 ), including cycloaliphatic, aromatic (the connecting carbon is sp 2 ) and / or aliphatic.
• hydrocarbon radical should be understood to mean a radical comprising hydrogen and carbon.
• hydrocarbon radicals can in particular be alkyls (taken in the etymological sense of an alcohol from which the OH function has been removed), including aralkyls or aryls, including alkylaryl.
• esters of phosphoric acid such as tributyl phosphate (sometimes designated by its English acronym of TBP) and phosphine oxides such as , for example, trioctylphosphine oxide (sometimes referred to by its English acronym of TOPO).
• the above compounds be liposoluble.
• these compounds must have a total of at least 8 carbon atoms, preferably at least 12.
• mention should be made of the relatively heavy amines ie - Say having at least 8 carbon atoms, preferably at least 12 carbon atoms.
• amines capable of being used by the present invention mention may be made of tributylamine, tri IsoOctylAmine (sometimes designated by TiOA) and tri n-OctylAmine (TOA).
• pyridines or substituted quinoleines Mention may also be made, as basic compounds, of the derivatives of nitrogen heterocycles which cannot be considered as amines, and in particular the derivatives of pyridine. In this case too, it is preferable to use pyridines or substituted quinoleines to have at least 8 carbon atoms, preferably at least 12, and even at least 15 carbon atoms.
• the basic compounds specified above and which act as fat-soluble bases can be as heavy as desired as long as they remain liquid or soluble in a solvent. However, to avoid having to handle too large quantities of solvents, it may be desirable to limit the number of carbons reduced to the basic function to a value at most equal to 50, preferably at most equal to 35.
• phosphoniums and especially quaternary ammoniums. These compounds form a base when associated with a hydroxide ion and have the ability to extract the sulfinates according to the present invention, but the elution is more difficult.
• quaternary ammoniums or phosphoniums advantageously have a number of carbons at least equal to 12, preferably 15.
• Said basic organic phase advantageously comprises a solvent little miscible with water, that is to say a solvent whose solubility in pure water is less than 5% by mass, preferably 2% by mass.
• solvents, or diluents are advantageously chosen from those which are usually used in liquid-liquid extraction used in a field other than that of organic chemistry, namely extractive metallurgy in aqueous mode.
• aromatic hydrocarbons such as benzene
• aliphatic hydrocarbons such as hexane, cyclohexane
• halogenated hydrocarbons such as halogenated and in particular chlorinated derivatives of benzene and petroleum fractions such as those sold under the Solvesso brand or those of the kerosene type.
• the ratio between the diluent and the compound serving as a lipophilic base is generally between 1.5 and 10 by mass.
• diluents are chosen according to their boiling points with a view to possible distillation, in particular of said polar solvents and / or of an alkanoic acid including fluoroalkanoic, to prevent them from boiling at the same time as other compounds; they are chosen so that they have higher boiling points than those of the compounds to be removed.
• their boiling point under atmospheric pressure is at least equal to 100 ° C., advantageously 150 ° C.
• Said sulfinic acid to be treated as seen above can be brought into contact with said liquid basic organic phase, either in the form of a mixture of salts, or in the form of an aqueous solution, or in the form of an aqueous suspension, or finally in the form of a solution in a polar aprotic solvent.
• the recovery of sulfinic acid or sulfinate is carried out by bringing said basic organic phase into contact with an aqueous phase.
• This contacting can be carried out in any device known for liquid-liquid exchanges and in particular in decanter mixer systems.
• This counter-extraction, or elution can be carried out co-current but it can advantageously also be carried out against the current.
• This latter implementation makes it possible to obtain concentrations of acids or salts of sulfinic acid of high concentration, while limiting the volume of aqueous phase and ipso facto the amount of organic product (s) in the aqueous phase (triple effect: salting out due to the saline nature, volume of the aqueous phase, density of the aqueous phase allow a more complete decantation).
• the aqueous phase used for the elution, or against the extraction can contain high concentrations of water-soluble bases.
• water-soluble bases mention may be made of alkaline earth metals of low atomic weight such as magnesium, and especially alkali metals and water-soluble amines, that is to say the amines whose total number of carbons is reduced to the function amino and at most equal to 6, advantageously to 4.
• ammoniums or quaternary phosphoniums are used in place of the hydroxide anion, anions having a particular affinity with quaternary ammoniums can be used.
• sulfinic acid Prior to the step of bringing said basic organic phase into contact with sulfinic acid, it may be appropriate to subject the materials containing sulfinic acid, or one of its salts, to contact with a solvent insoluble in water, or sparingly soluble in water, and relatively polar.
• solvents capable of meeting these constraints, mention may in particular be made of alkyl esters such as ethyl acetate, ethers which are not soluble in water such as ethyl ether, chlorinated and hydrogenated solvents which they are aromatic or they are aliphatic such as, for example, methylene chloride or dichlorobenzene.
• This contacting makes it possible to better eliminate, on the one hand, the polar aprotic solvent which may be present and, on the other hand, the alkanoic acids which may be present in the reaction medium.
• reaction mixture 1 is introduced into a distillation device, optionally under vacuum, where the polar aprotic solvent is removed as much as possible, generally partially.
• the reaction mixture (to which an aqueous phase will generally have been added) which comprises a liquid phase and a solid phase, is filtered in a step B before or after the addition of acids, in general a strong mineral acid.
• This filtration gives, on the one hand, a solid residue which is rejected and which is represented by a double line and, on the other hand a liquid phase, which is subjected to a step C of liquid-liquid extraction by means of a water-immiscible but semi-polar diluent such as methylene chloride.
• a water-immiscible but semi-polar diluent such as methylene chloride.
• This organic phase can undergo an elution step by means of the aqueous phase ⁇ A2.
• This ⁇ A2 phase to facilitate the elution, or counter-extraction, of the alkanoic acids may contain basic compounds.
• This elution can be carried out in one or more stages and, advantageously, against the current in order to be able to recover the fluoroalkanoic acids which were used as raw material for the synthesis of sulfinic acid.
• stage D the aqueous phase resulting from stage C is subjected to the action of an organic phase ⁇ O3: usually, this basic organic phase comprises an amine, or even a substituted pyridine.
• this basic organic phase comprises an amine, or even a substituted pyridine.
• this step D can be carried out in one or more stages. However, it is preferable that this step D comprises at least two stages so as to better exhaust the aqueous phase and to better charge the organic phase with sulfinic derivatives.
• the organic phase ⁇ O3 can be subjected to an elution by means of an aqueous phase ⁇ A3.
• This elution can be carried out in one or more stages if a high concentration is desired, it is desirable to bring it in several stages.
• This aqueous phase ⁇ A3 is advantageously when using amines and pyridines loaded with basic compounds capable of releasing the amine.
• the organic phase ⁇ O3 can be subjected to a washing step using a concentrated sulfinic salt so as to avoid the presence of acidic impurities such as residual alkanoic acid after step C.
• the phase aqueous from step D, phase 4 constitutes the spent aqueous phase which can either be used to make sulfuric acid from an oleum or be recycled as an aqueous phase before step C liquid-liquid extraction.
• a purge should be provided to avoid the accumulation of mineral matter in the aqueous phase.
• elution may well understood to be carried out by a strong base in aqueous medium, soda, potash, but it can also be carried out by means of an anion having a good affinity for quaternary ammoniums.
• the same rheogram can be used by using as basic organic compound in the ⁇ O3 phase an oxygenated compound and, in particular, a phosphorus compound of the tributylphosphate or trioctylphosphine oxide type.
• an oxygenated compound and, in particular, a phosphorus compound of the tributylphosphate or trioctylphosphine oxide type.
• very little aqueous phase should be used and a large amount of strong acid, advantageously sulfuric, should be introduced.
• step D it is advisable to extract aqueous phases whose pH is at most equal to 0, advantageously to - 0.5.
• the basic compound is brought into direct contact with the reaction mixture before or after distillation of a polar aprotic solvent which may be present.
• a polar aprotic solvent which may be present.
• the reaction mixture is then subjected to distillation to remove the non-acidic organic compounds. Once these compounds have been removed, it is possible to add a medium acid or a quantity of strong acids just sufficient to release any alkanoic acids, including fluoroalkanoic acids, present in the reaction medium. Once this addition has been carried out, the distillation can be resumed to remove the various volatile alkanoic acids under the operating conditions.
• the acids which can be used in this second step are advantageously acids of medium strength such as the second acidity of sulfuric acid or the first acidity of phosphoric acid (pKa between -1 and 2, preferably about 1). These acids are advantageously non-volatile mineral acids.
• sulfuric acid can be used in a substantially equimolecular mixture with one of its salts so as to form the bisulfate which will serve as a medium acid.
• reaction mixtures exemplified in the various processes for the synthesis of sulfinic acid are essentially reaction mixtures giving salts.
• the present techniques can easily be transposed by eliminating the step of releasing the acid by adding acids, especially sulfuric.
• EA represents an electro-attractor group whose possible functions are inert under the conditions of the reaction, advantageously fluorine or a perfluorinated residue of formula C n F 2n + 1 , with n integer at most equal to 8, advantageously 5, the total number of carbon of R f being advantageously between 1 and 15, preferably between 1 and 10.
• 1,956 g of an aqueous solution composed of 263 g (1.53 mol) of potassium trifluoromethanesulfinate, 68.8 g (0.45 mol) of potassium trifluoroacetate and 126 g of dimethylformamide is acidified with 1 18 g 98.7% sulfuric acid (about 1.2 mol).
• the dimethylformamide content of the resulting aqueous phase is 0.1%.
• This aqueous phase is then subjected to a liquid-liquid extraction operation using 425 g of tributylamine (2.3 mol) dissolved in 500 g of toluene.
• the toluene phase is treated with an aqueous potassium solution corresponding to 8.7 g of potassium.
• the resulting aqueous phase is dehydrated by azeotropic entrainment with toluene to lead, after filtration to 250 g of a white solid composed of 233 g of potassium trifluoromethanesulfinate
• trimethylammonium trifluoromethanesulfinate 400 g of a reaction medium composed of 10.6 g of potassium trifluoroacetate and 27.7 g of potassium trifluoromethanesulfinate in solution in dimethylformamide is concentrated under reduced pressure so as to obtain 80 g of solution.
• This medium is diluted with 160 g of water after addition of 27.7 g of concentrated hydrochloric acid.
• the residual aqueous phase then contains a DMF level of less than 0.5% and a trifluoroacetic acid content of less than 0.5 g.
• the aqueous phase is then extracted with 29.8 g of tributylamine in solution in 55 ml of toluene.
• the toluene phase is eluted with 22.7 g of a 45% aqueous solution of trimethylamine.
• Dimethylformamide is removed by distillation under a reduced pressure of 15 mbar at 60 ° C.
• the organic phase thus obtained is extracted twice
• the aqueous phases are combined and contain 8.3 g of potassium trifluoromethanesulfinate and 1.1 g of potassium trifluoroacetate.
• the other impurities are present in trace amounts.

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• 2000
  • 2000-01-04 FR FR0000051A patent/FR2803295B1/fr not_active Expired - Fee Related
• 2001
  • 2001-01-04 CA CA002396433A patent/CA2396433A1/fr not_active Abandoned
  • 2001-01-04 AU AU33827/01A patent/AU3382701A/en not_active Abandoned
  • 2001-01-04 WO PCT/FR2001/000025 patent/WO2001049659A1/fr not_active Application Discontinuation
  • 2001-01-04 EP EP01905851A patent/EP1244618A1/de not_active Withdrawn
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