FR2787346A1 - Regenerating high molecular organic acid, e.g. l-camphorsulfonic acid, from aqueous salt solution, by electrodialysis using apparatus with high permeability anion exchanger dialysis membrane - Google Patents

Abstract

Regeneration of high molecular organic acids (I) from aqueous solutions of their salts is effected by electrodialysis using apparatus comprising at least one unit cell formed by three adjacent compartments, i.e. a central compartment defined by a high permeability anion exchange dialysis membrane and a cation exchange membrane and two side-compartments each bounded by a bipolar membrane. Regeneration of high molecular organic acids (I) of molecular weight 200 or more from aqueous solutions of their salts is effected by electrodialysis using apparatus comprising at least one unit cell formed by three adjacent compartments, i.e. a central compartment defined by a high permeability anion exchange dialysis membrane and a cation exchange membrane and two side-compartments each bounded by a bipolar membrane. A continuous potential difference is applied using an anode and a cathode at the ends of the device, to generate an electrical field. The (I) salt solution is circulated through the central compartment of each cell. A solution of regenerated (I) solution is recovered from the anode side compartment; and a solution of base corresponding to the cation of the salt is recovered from the cathode side compartment.

Description

The present invention relates, in general, to a method

for

  the regeneration of high molecular weight organic acids.

  In particular, the invention relates to a process for the regeneration of organic acids of high molar mass, by electrodialysis of an aqueous solution of their salts. Acids are important intermediaries for many

  chemical synthesis processes.

  After use, these acids are often found in the form of aqueous saline solutions which can be regenerated and recycled, in particular in the case of

most expensive acids.

  Bipolar membrane electrodialysis enables such regeneration to be carried out. According to this known method, electrical energy is used to dissociate the water from the saline solution and reconstitute the acid and the base separately according to the reaction:

MX + H20 - HX + MOH

acid base salt.

  In order to carry out this reaction and to keep the different compounds involved therein separated, ion-exchange membranes are used and, more particularly, bipolar membranes made up of two faces selective for anions and cations respectively. Under the effect of an electric field, these membranes allow the following reaction:

H20 -) H + + OH-

  as illustrated in Figure 1 in which (BP) represents a bipolar membrane.

  The H + and OH ions are then reassociated respectively with the X 'anions and M + cations coming from the salt of the solution, and the products obtained are kept separated by

  conventional ion exchange membranes (monopolar).

  Such a process for regenerating acids and bases from their salts has already received numerous applications, for example:

  * sulfuric acid from sodium sulfate (patent application JP 4-

  3 0 132605 and Chem. Ing. Tech. 61 (1989) N 5, pp 428-429) * hydrochloric acid from sodium chloride [CA1 17 (16): 153850m; (2): 11524u; 92 (6): 43961f and 92 (4): 25083s] * butyric acid from its sodium salt [CA 116 (18): 182 124n] * maleic acid from its ammonium salt (Chem. Ing. Tech cited above) * boric acid from borates [CA107 (4): 29755 p and CA 114 (4) 30673m] e tartaric acid from its potassium salt (patent application FR

2646421)

  * organic sulfonic acids [CA 71 (12): 564 51f and US patent 5,221,443]. If the bipolar membranes available to date do not pose any particular problems of use, on the other hand, the anion or anion exchange membranes and the cation or cation exchange membranes which are therein

  associated, must be permeable to anions and cations respectively.

  In the case of acids usually regenerated by an electrodialysis process, that is to say acids of low or medium molar mass, the permeability of the anionic membrane to the anions of the acids does not generate

particular difficulties.

  On the other hand, in the case where the acid anion is an organic anion of high molar mass, a permeability problem may arise. This can be the case, for example, of the anion of l-camphosulfonic acid or R (+) - camphosulfonic acid:

H3C CH3

A CH2 SO3H

  o this acid cannot be regenerated from its salts in an electrodialysis process using conventional membranes, in particular

  anionic membranes usually used in this type of method.

  For example, in the context of the development of the present invention, the electrodialysis process described in US Pat. No. 5,221,443 applied to the regeneration of l-camphosulfonic acid from an aqueous solution was tested. of its potassium salt by using a bipolar membrane, a cationic membrane marketed under the brand SELEMION CMV by Asahi Glass and an anionic membrane marketed under the brand NEOSEPTAe AMX by Tokuyama Soda. In this application, no results were provided, the membrane

  anion exchanger not allowing the passage of lcamphosulfonate ions.

  The process of this patent therefore appears to be suitable for the regeneration of organic acids with a molar mass of less than 150 g. mole ', as evidenced by the examples described there, but not for the acids of higher molar mass in particular the acids of molar mass greater than or equal to 200g. mole1 like l-camphosulfonic acid. The search for a method, for the regeneration of organic acids of high molar mass, in particular greater than 200, by an electrodialysis process

  therefore remains of undoubted interest.

  Now, it has now been discovered, unexpectedly, that certain so-called high permeability dialysis membranes allow the passage of large organic anions and, therefore, can be used advantageously in combination with standard cationic membranes and membranes. conventional bipolar in electrodialysis methods for the regeneration of acids corresponding to these anions, in particular acids

  organic with high molar mass, that is to say greater than or equal to 200 g. mole-

  in particular l-camphosulfonic acid.

  This observation is all the more surprising since these membranes with high permeability, generally used in acid dialysis processes independent of any electrochemical process, do not exhibit any selectivity in this application to dialysis since both hydrated protons and anions

diffuse through them.

  Consequently, the subject of the invention is a process for the regeneration of organic acids with a molar mass greater than or equal to 200 gmol from an aqueous solution of their salts, for example their alkali metal salts, process according to which: a) an electrodialysis device is constituted comprising at least one elementary cell configured in three contiguous compartments, a median delimited by a dialysis membrane anion exchange with high permeability and a cation exchange membrane and two lateral ones each bounded by a bipolar membrane, which is subjected to a continuous potential difference generated by an anode and a cathode situated at the ends so as to create an electric field, b) an aqueous solution of the organic acid salt to be regenerated is circulated in the middle compartment of each cell, c) a regenerated organic acid solution is collected in the side compartment on the anode side and in the lateral compartment on the cathode side, a solution

  basic corresponding to the cation of the regenerated organic acid salt.

  Schematically, the electrodialysis device in question, consisting of a cell or more generally of a stack of cells each configured in 3 compartments, corresponds to the sequential formula:

(BP + / A / AN / S / C + / B), I

in which:

  -BP + represents a bipolar membrane.

  A represents the compartment intended for the acid AN- represents an anionic membrane with high permeability S represents the compartment intended for the el C + represents a cationic membrane B represents the compartment intended for the base n represents the number of cells The membranes of dialysis exchangers d anions used in the process of the invention are capable of promoting the passage of anions of high molar mass in

  particular of anions originating from acids with a molar mass greater than or equal to 200 g.

  mole-, generally anions comprising one or more sulfonate or phosphonate groups so as to contribute to the regeneration of acids comprising one or

  several sulfonic or phosphonic groups.

  These are semi-permeable membranes with a thickness varying from 0.03 to 0.2 mm, generally composed of a polymer matrix, for example a polystyrene provided with crosslinking groups such as divinylbenzene groups carrying chemical functions. positively charged including

  ammonium, alkylammonium or dialkylammonium groups.

  Depending on its crosslinking rate, this polymer matrix is able to observe a certain amount of water: the lower this amount, the more the

  the membrane's capacity to swell with water is important and vice versa.

  The anion exchange membranes used in the process of the invention, being characterized by a low crosslinking rate allowing them to absorb from% to 70% of their weight of water, will therefore be of high permeability to anions of size 3 0 important since this permeability is directly linked to the amount of water capable

  to be absorbed by these membranes.

  Anionic membranes of this type can for example be the membranes sold under the brand NEOSEPTA AFX or NEOSEPTAe AFN by the company Tokuyama Soda or even under the brand RAIPORE ADM-4000 by

  Pall Rai company or the SELEMION DSV brand by Asahi Glass company.

  For example, the anion exchange membranes with high permeability below have the properties indicated: Membrane Resistance of Number of Exchange Capacity Content NEOSEPTA surface (Q cm2) transport (CI-) (meq / g) in water (%)

AFX 1.0-1.5 0.98 1.4-1.7 36.5

AFN 0.4-1.5 0.98 2.0-3.5 57.0

  By way of comparison, an anionic membrane of standard type, analogous to those appearing in US Pat. No. 5,221,443, meets the following characteristics: Membrane Resistance Number of Exchange Capacity Content NEOSEPTA surface (Q cm2) transport (CI-) ( meq / g) in water (%)

AMX 2.5-3.5 0.98 1.2-1.5 22.3

  However, the anionic membranes with high permeability of the invention being poorly crosslinked are endowed, for this reason, with a low dimensional stability which

  poses sealing problems.

  However, it has been found, in the context of the invention, that the stability of these membranes can be greatly improved, so as to avoid any subsequent deformation if they are previously treated, for example by immersion, using an aqueous solution. acid to regenerate for example an acid solution at a concentration

from 0.8 to 1M.

  As the cationic membrane, a semi-membrane is usually chosen.

  permeable conventional cation exchanger, for example a membrane sold under the brand SELEMION CMV by the company Asahi Glass or under

  the brand NEOSEPTA CMX by the company Tokuyama Soda.

  These cation exchange membranes generally have a thickness of between 0.1 and 11 mm and a pore diameter of between 1 and 30 μm. They are in fact composed of a polymer matrix, for example a polystyrene / divinylbenzene resin containing chemically linked anionic groups,

  such as carboxylate or sulfonate groups.

  The bipolar membrane, on the other hand, has an asymmetrical structure and has anionic groups on one of these faces and cationic groups

on the opposite side.

  These bipolar membranes can be produced for example by intimately juxtaposing a cationic membrane and an anionic membrane as described in patent application EP-A-193 959. However, membranes of this type can be obtained commercially for example BP1 membrane from Tokuyama Soda or AQUALYTICSE brand membrane from The company

Burn Water Systems, lnc.

  The method of the invention, using the electrodialysis device shown diagrammatically in its elementary part with sequential formula 1, consists in releasing the organic acid with a molar mass greater than or equal to 200 g. mol- ', for example a sulfonic or phosphonic acid, from an aqueous solution of its salts, generally alkali metal salts, preferably sodium or potassium salts, by passing this aqueous salt solution through the compartment center (S) of the electrodialysis cell while a solution of the regenerated acid is released in the lateral compartment (A) and a solution of the corresponding base

  the cation present in the salt is collected in the side compartment (B).

  For the implementation of this process, an aqueous solution of organic acid in question is introduced into compartment (A) of the cell of the device, generally a 0.4 to 0.8 N solution of this acid and in the compartment B an aqueous solution of the base corresponding to the cation present in the salt, usually a 0.4 to 0.8 N solution while the salt is placed, in the form of

  aqueous solution, in compartment (S).

  Using two electrodes, an anode and a cathode, the

  cell with a potential difference of up to 400 to 500 V / m2.

  In this way, an electric field necessary for electrodialysis is created, the density of electric current required for the production of this field being at

  maximum of 1000 A / m2 of cell, generally from 125 to 865 A / m2.

  These electrodes are located at the ends of the electrodialysis cell and are themselves housed in compartments, namely an anode compartment and a cathode compartment, separated from this cell by additional ion exchange membranes, preferably cationic membranes. . These cationic membranes will be of sufficient strength to avoid deterioration of the other membranes of the device due to the corrosive effect of the electrodes. It can be, in particular, a cationic membrane formed of a fluoropolymer, for example the

  membrane commercially available under the NAFION brand from the company E.l.

DUPONT DE NEMOURS & COMPANY.

  In addition, during the electrodialysis operation, the anode and cathode compartments are continuously traversed by a solution for rinsing the electrodes, for example an acid or basic solution such as a solution of the base to be formed or

acid to be recovered.

  In this process, the electrically neutral impurities possibly present in the aqueous solution of the salt of the acid to be regenerated will be retained in

  the compartment (S) of the cell of the device.

  The process of the invention can be carried out either discontinuously or semi-continuously, at a temperature between 5 C and 95 C, preferably at a temperature between room temperature and 60 C, by

  example at a temperature of the order of 40 C and under a pressure of 0.3 to 0.5 bar.

  In the case of an implementation in discontinuous phase of the process of the invention, the aqueous solution of the organic acid salt to be regenerated is circulated in a closed circuit so as to gradually deplete it during its successive passages in the middle compartments of the cells, that is to say the compartments (S). It is then possible to collect respectively a regenerated acid solution and a base solution corresponding to the cation present in the salt, either by sampling from containers situated respectively at the outlet of the lateral compartments on the anode side and lateral compartments on the cathode side of the cells of the device, 2 0 that is to say the respective compartments (A) and compartments (B), either by causing them to circulate in a closed circuit with a view to recycling them respectively in the lateral compartments on the anode side and on the lateral compartments on the cathode side of the

  cells in question to enrich them to the desired concentration.

  Likewise, in the case of an implementation in a semi-continuous phase of the process of the invention, the aqueous solution of the organic acid salt to be regenerated is advantageously circulated in a closed circuit so as to gradually deplete it over time. during its successive passages in the median compartments of the cells, that is to say the compartments (S). We can then collect respectively a regenerated organic acid solution and a base solution corresponding to the cation present in the salt, either by overflow from containers located respectively at the outlet of the lateral compartments on the anode side and lateral compartments on the cathode side of the cells of the device. receiving these solutions, that is to say the respective compartments (A) and compartments (B), or by causing them to circulate in a closed circuit with a view to recycling them respectively in the lateral compartments on the anode side and 3 5 lateral compartments on the side cathode of the cells in question to enrich them up to

the desired concentration.

  The following nonlimiting Examples illustrate the process of the invention with reference to the appended drawings in which: - Figure 2 represents a diagram of an electrodialysis device formed by a stack of 4 cells each configured in 3 compartments - Figure 3 represents a diagram of the ionic dissociation of potassium 1- camphosulfonate and the reassociation into acid and base in a cell configured in 3 compartments - Figure 4 represents a diagram of installation for the regeneration in semi-continuous phase of the acid I-camphosulfonic from an aqueous solution of

Potassium I-camphosulfonate.

EXAMPLE 1

  Regeneration of 1-camphosulphonic acid (batch process) The regeneration of l-camphosulphonic acid was carried out from an aqueous solution of potassium l-camphosulphonate by use in an electrodialysis device such as shown schematically in Figure 2

  comprising a stack of 4 elementary cells with a total area of 0.04m2.

  This stack is located between two electrodes: an anode (1) and a cathode (2) connected to a regulated direct current generator (3). In addition, the set of 20 cells is provided at its ends with two compartments (ER) and (ER ') for rinsing the electrodes, these compartments being each bounded by a cationic membrane.

resistant (N) brand NAFION.

  These compartments are supplied by a conduit (4) in which a 2.5N potassium hydroxide solution circulates, the conduit further comprising a reservoir

  (5) for the basic solution and a circulation pump (6).

  Each cell comprises a series of 3 membranes: a bipolar membrane (7) of type BP1 from the company Tokuyama Soda, generator of protons and hydroxyl groups, a high-permeability anion exchange membrane (8) of the NEOSEPTAe AFX brand, treated beforehand by immersion in a 0.8 to 1 M solution of l-camphosulfonic acid and a cation exchange membrane (9) of

SELEMION CMV brand.

  These membranes delimit 3 compartments: a lateral compartment (A) on the anode side for the l-camphosulfonic acid solution, a median compartment (S) for the potassium l-camphosulfonate solution and a compartment (B) on the cathode side.

  3 5 for the potassium hydroxide solution.

  Each compartment is provided, at its outlet, with a conduit shown here for the group of compartments (S), namely the conduit (10). This conduit, connected along its route to a reservoir (11) which successively supplies a filter (12), a contrifugal pump (13) and a flow meter (14) is connected on the other hand to the inlet of the corresponding compartment. The general conditions for implementing this device are as follows: * maximum voltage for this stack of cells 20 volts * maximum electric current for this stack 10 amps * flow rate of the electrode rinsing solution 501 / h / electrode * flow rate each reagent 90Vh * pressure at the inlet of the stack 0.4-0.5 bar The potassium l-camphosulfonate solution is first rid of the presence of its carbonate by acidification using acid l -camphosulfonic to

  125g (0.54 mole) of acid per kg of saline.

  The regeneration process is then carried out batchwise and at a temperature of 40 ° C. with at the start in compartment (B) a 0.52N potassium hydroxide solution, in compartment (A) a solution of l-camphosulfonic acid 0.28N, in compartment (S) the solution of potassium l-camphosulfonate prepared previously and in the anode and cathode compartments a

  2.5N potassium hydroxide solution.

  The high electrical resistance of the electrodialysis device, under these operating conditions, does not make it possible to apply the maximum admissible electric current density by the membranes, which in this case is 9.6A, ie 1000 A / m2. We therefore regulate at an intensity which corresponds to the maximum voltage tolerated for the device, ie 20V knowing that Vmax = 3V per cell + 8V drop in difference in

potential at the electrodes.

  Thus, the current density varies from 125 A / m2 at the start to 865 A / m2 at the end of the test. Under the effect of the electric field applied to this device, an ionic dissociation occurs followed by a reassociation as shown diagrammatically in FIG. 3 in the appendix on which the l-camphosulfonate anion (CS ') and the counter cation (K +) migrate from potassium l-camphosulfonate solution (KCS) located in compartment (S) and go to the anode or cathode respectively, the anion entering compartment (A) after having crossed the anionic membrane high permeability (AN), the cation entering the compartment (B) after passage

by the cationic membrane (C).

  Under the effect of this same electric field, the water present is in parallel dissociated into protons (H +) and hydroxyl anions (OH-) via the bipolar membrane (BP) whose proton-generating face is turned towards the cathode and the hydroxyl anion generating face towards the anode. Thus the protons (H +) migrate towards the cathode in the compartment (A) and the hydroxyl anions (OH-) move towards the anode in the compartment (B) where they combine respectively with the camphosulfonate anions (CS ' ) who migrated there or with the cations

  (K +) to form free l-camphosulfonic acid (HCS) or free base (KOH).

  The duration of this test is 15h, which allows to reach a concentration

  in potassium hydroxide of 1.78M and an acid concentration 1-

  camphor sulfonic equal to 0.96M. The faradaic acid yield at the start is close to 36% then gradually decreases to 13% at the end of the test, which corresponds to an overall faradaic yield close to 19%. Similarly, the faradic base yield, close to 57% at the start, gradually decreases to 27% in

  end of test, which corresponds to an overall faradic yield close to 35%.

  The energy consumed is equal to 2395 kWh / tonne of l-camphosulfonic acid

  and the productivity is equal to 0.91 kg / h.m2 of cell or 3.9 mole / h. m2 of cell.

  In this way, 2.5 kg of l-camphosulfonic acid are obtained which, after crystallization, has the following characteristics: Appearance: practically white crystalline powder

[(] D20: -23.0

  Acidimetric titer: 99.4% Enantiomeric purity (in gas chromatography): 99.3% S (-) - Camphosulfonic acid: trace (<< 0.2%) 2 5 A comparative test carried out under exactly the same conditions at the start of an electrodialysis device as described above comprising conventional anion exchange membranes of the brand NEOSEPTAe AMX did not make it possible to regenerate l-camphosulfonic acid from its potassium salt, the anionic membrane used neither allowing the passage of l-camphosulfonate ions

  Nor therefore the electric current.

EXAMPLE 2

  Re-regeneration of l-camphosulfonic acid (semi-continuous process) The regeneration of l-camphosulfonic acid from an aqueous solution of potassium l-camphosulfonate was carried out in an electrodialysis device. comprising a stack of 7 elementary cells of

  2dm2 each of active surface as shown in Figure 4 in the appendix.

  This stack is located between two electrodes: an anode (14) and a cathode (15) connected to a regulated direct current generator (16). In addition, the cell assembly is provided at its ends with two compartments (17) and (18) for rinsing the electrodes, these compartments being each bounded by a resistant cationic membrane (19) of the NAFION brand. These compartments are supplied by a conduit (20) in which a hydroxide solution circulates

  2.5N potassium from a reservoir (21).

  A pump (22) circulates this basic rinsing solution.

  Each cell comprises a series of 3 membranes: a bipolar membrane (23) of BP1 type from the company Tokuyama Soda, generator of protons and hydroxyl groups, a high-permeability anion exchange membrane (24) of the NEOSEPTAe AFX brand, treated beforehand by immersion in a 0.8 to 1M solution of l-camphosulfonic acid, and an exchange membrane of

  SELEMION CMV brand cations (25).

  These membranes delimit three compartments: a lateral compartment (A) on the anode side for the l-camphosulfonic acid solution, a median compartment (S) for the potassium l-camphosulfonate solution and a compartment (B) on the side

  Cathode for potassium hydroxide solution.

  The device is also equipped with conduits (26) (27) (28) which respectively supply reservoirs (29) (30) (31) intended to receive a recycled solution respectively of potassium l-camphosulfonate, of l-camphosulfonic acid and potassium hydroxide while at the outlet of each of these reservoirs conduits (32) (33) (34) equipped with circulation pumps feed the stack of

  cells in saline, acid and basic solutions respectively.

  The general conditions for using this device are as follows: * flow rate of the electrode rinsing solution 150 I / h per electrode * flow rate of the acid solution 130 I / h * flow rate of the salt solution 130 I / h * flow rate of the base solution 150Vh * pressure at the inlet of the stack 0.3-0.5 bar The potassium l-camphosulfonate solution is freed from its carbonate beforehand by acidification to pH = 3 to using l-camphosulfonic acid. This decarbonated solution, coming from the reservoir (29) via the conduit (32), is then subjected in discontinuous phase and at a temperature of 40 C to the treatment.

  electrodialysis which gradually depletes the salt. At the same time, the acid I-

  camphorsulfonic and potassium hydroxide produced are brought into reservoirs (30) and (31) respectively. They are then partially collected continuously by overflow, the acid in the tank (35) and the base in the tank (36) at concentrations of the order of 0.4 mol /! for the acid and of the order of 1 mol / l for the base, these concentrations being maintained in the reservoirs (30) and (31) by injection of demineralized water coming from the tank (37) by means of conduits (38 respectively) ) and (39) which include metering pumps (40) regulated by the concentrations of

acid and base.

  As for the acid solutions of the reservoir (30) and of basic solution of the reservoir (31) these are brought by their respective conduits (33) and (34) into the respective compartments (A) and (B) of the cells of the device o they

are recycled.

  During operation, it is regulated at a current intensity of the order of OA which corresponds to a maximum voltage tolerated for each lower cell or

  equal to 3V x 7 = 21V + 7V drop in potential difference at the electrodes.

  Under normal conditions, the faradic yield of lcamphosulfonic acid is established at a value of 13 to 15% at the start, then stabilizing during the

time at a level of 7%.

  In this way, l-camphosulfonic acid is obtained, which after crystallization has the following characteristics: Appearance: off-white powder [(a] D20: -22.4 Acidimetric titer: 99.5 - 99.7% Enantiomeric purity (in gas chromatography): 99.4% 2 5 S (-) camphosulfonic acid: <0.02%

Claims (16)

  1. Process for the regeneration of organic acids with a molar mass greater than or equal to 200 g.mole'1 from an aqueous solution of their salts, characterized in that: a) an electrodialysis device is formed comprising at least one elementary cell configured in three contiguous compartments, a median bounded by a dialysis membrane anion exchange with high permeability and a cation exchange membrane and two sides each bounded by a bipolar membrane, which is subjected to a difference of continuous potential generated by an anode and a cathode situated at the ends so as to create an electric field, b) an aqueous solution of the organic acid salt to be regenerated is circulated in the median compartment of each cell, c) I '' a regenerated organic acid solution is collected in the side compartment on the anode side and in the side compartment on the cathode side, a   basic solution corresponding to the cation of the regenerated organic acid salt.   2. Method according to Claim 1, characterized in that the membrane   High permeability anion exchange dialysis is capable of absorbing 30% to % of its weight in water.   2 0 3. Method according to Claim 1 or 2, characterized in that a dialysis membrane anion exchange with high permeability treated with   beforehand with an aqueous solution of the acid to be regenerated.   4. Method according to Claim 3, characterized in that the solution   aqueous contains 0.8 to 1 M of acid to be regenerated.   5. Method according to one of Claims 1 to 4, characterized in that the   anion exchange dialysis membrane is a branded membrane   NEOSEPTA AFX, NEOSEPTA AFN, RAIPORE ADM-4000 or SELEMION DSV.   6. Method according to one of Claims 1 to 5, characterized in that the   potential difference is 400 to 500 V / m2 of cell.   7. Method according to one of Claims 1 to 6, characterized in that the   electric field is produced from an electric current density not exceeding no 1000mA / 2 cell.   8. Method according to Claim 7, characterized in that the density of   electric current is from 125 to 865A / m2 of cell.   9. Method according to one of Claims 1 to 8, characterized in that it is   implemented at a temperature between 5 C and 95 C.   10. Method according to Claim 9, characterized in that the temperature   is between room temperature and 60 C.   11. Method according to one of Claims 1 to 10, characterized in that it   is implemented at a pressure of 0.3 to 0.5 bar.   12. Method according to one of Claims 1 to 11, characterized in that it   is implemented in a discontinuous or semi-continuous phase.   13. Method according to one of Claims 1 to 12, characterized in that it   is implemented in a semi-continuous phase by circulating in a closed circuit the aqueous solution of the organic acid salt to be regenerated so as to gradually deplete it during its successive passages in the median compartments of the cells then by collecting a solution of regenerated organic acid and a base solution corresponding to the cation of the regenerated organic acid salt, either by overflow from containers situated respectively at the outlet of the lateral compartments on the anode side and lateral compartments on the cathode side of the cells receiving these solutions, or by causing them to circulate in a closed circuit in order to recycle them respectively in the side compartments on the anode side and on the side compartments   cathode side of the cells to enrich them up to the desired concentration.   14. Method according to one of Claims 1 to 12, characterized in that it   is implemented in a discontinuous phase by circulating in a closed circuit the aqueous solution of the organic acid salt to be regenerated so as to progressively deplete it during its successive passages in the median compartments of the cells 20 then collecting a solution of regenerated acid and a base solution corresponding to the cation of the regenerated organic acid salt, either by taking from containers situated respectively at the outlet of the cells from the lateral compartments on the anode side and lateral compartments on the cathode side of the cells, or by bringing them circulate in a closed circuit in order to recycle them respectively in the side compartments on the anode side and side compartments on the cell side for   enrich them to the desired concentration.   15. Method according to one of Claims 1 to 14, characterized in that it   is used for the regeneration of organic acids with a molar mass greater than or equal to 200g.mole'1 comprising one or more sulfonic groups Or phosphonic.   16. Method according to Claim 15, characterized in that it is set   works for the regeneration of l-camphosulfonic acid.