DD299056A5 - PROCESS FOR THE PREPARATION OF 2-CARBOXYMETHYLSULFONYL-PROPANE-1,3-DISULFONATE - Google Patents

Abstract

The invention relates to a process for the preparation of * (sulfonylcarboxylic acid) of the general formula * which can be used as intermediates and as hydrotropes in microemulsion systems. According to the present invention, molar amounts of sodium allylsulfonate are reacted with chloroacetic acid and twice the molar amount of sodium bisulfite in the presence of a catalytic amount of peroxodisulfate, and the resulting reaction solution is converted to sulfonylcarboxylic acids of general formula (I) after addition of a catalytic iodide amount by heating. Formula (I) {* sulfonylcarboxylic acid; Intermediates; Hydrotropes in microemulsion systems; sodium allyl sulfonate; chloroacetic acid; sodium bisulfite; Peroxodisulfate as a catalyst; Iodide as a catalyst}

Description

in which

M is a cation, preferably Na ⁺ and

R is hydrogen or an alkyl radical having 1 to 14 carbon atoms, characterized in that allyl sulphonates, preferably sodium allyl sulphonate, of the general formula (II)

..3 «M CD

in the

M has the abovementioned meaning,

with molar amounts of an α-halocarboxylic acid, preferably α-chlorocarboxylic acid of the general formula (IiI),

Cl

CO ₂ H

(III)

in the

R has the abovementioned meaning,

and the double-molar amount of a Mexailhydrogensulfits, preferably sodium bisulfite, reacted in the presence of a catalytic amount of a peroxodisulfate in the first process step and in the second process step, the resulting reaction solution after addition of a catalytic amount of iodide until heated to boiling until the sulfate content of the reacting solution Zero has dropped.

2. The method according to claim 1, characterized in that in the first process step 1 to 5 mol% peroxodisulfate, based on the allylsulfonate used, are added as a catalyst.

3. The method according to claim 1 and 2, characterized in that the pesoxodisulfate in two portions of 2 mol%, based on the allyl sulfonate, is added.

4. The method according to claim!, Characterized in that in the second step 5 to 50 mmol of sodium, potassium or ammonium iodide / mol allylsulfonate are added as a catalyst.

Field of application of the invention

The invention relates to a process for the preparation of 2-carboxymethylsulfonyl-propane-1,3-disulfonates (sulfonylcarboxylic acids) of the general formula (I)

MO ₃ S

SO ₃ M

(I)

in which

M is a cation, preferably Na ⁺ and

R represents hydrogen or an alkyl radical having 1 to 14 carbon atoms.

The new sulfonylcarboxylic acids of the formula 1), as organic intermediates, represent a reactive building block for further syntheses or can be used as hydrotropes in microemulsion systems.

Characteristic of the known state of the art

2-Carboxymethylsulfonyl-propane-1,3-disulfonates of the general formula (I), as well as processes for their preparation are not yet known. Other alkyl or aryl-α-sulfonylcarboxylic acids have been known for a long time (A. Schöberl and A. Wagner in "Methoden der organischen Chemie", Houben-Weyl, Vol. IX, p.227ff. (19551 and M. Quaedvlieg , ibid., p. 298) According to S.Gabriel, Bar., Engl., Ges., 14, 833 (1881), for example, by heating sodium benzenesulfinate with sodium chloroacetate in aqueous solution according to the following equation

Aromatic-SOjNa + CICH ₂ CO ₂ Na- ArOiTiAl-SO ₂ CH ₂ CO ₂ Na + NaCl

initially obtained the sodium salt of benzenesulfonylacetic acid. From the salt, the sulfonylacetic acid can then be released by addition of a mineral acid,

In contrast, studies by A.Courtin, H.-R.von Tobel and G.Auerbach, HeIv. Chim. Acta 63,1412 (1980), according to which when 24 hours of heating 1 mol of 2-nitrobenzenesulfinic acid, 2 mol of bromoacetic acid and 2 mol of sodium hydroxide in aqueous solution under reflux in 91% yield only the methyl (2-nitrophenyl) sulfone is obtained.

Officially, under the acidic reaction conditions, the resulting carboxymethyl arylsulfone is immediately decarboxylated to methylarylsulfone.

Recently, the salts of 1,3-disulfonato-propane-2-sulfinic acid as potential starting materials for the synthesis of new substituted sulfonylcarboxylic acids of the general formula (I) as technically readily available compounds available. For example, such sodium sulfinates are obtained by free-radically initiated sulfosulfination of sodium allylsulfonate also present on an industrial scale with sodium hydrogen sulfite according to DD 225992 A1 or EP 163320A3.

However, attempts failed, which were carried out according to the prior art, for. B. trisodium-1,3-disulfonato-2-sulfinatopropan with Nairiumchloracetat to appropriately substituted a-sulfonyl acetate to carboxymethylate. The resulting reaction solution, which consisted of a complex mixture of starting materials, secondary products and also Hern target product, could not work up to the desired sulfonylacetic acid due to the polar character of the starting and reaction products.

Thus, starting from the salts of 1,3-disulfinatopropane-2-sulfinic acid, there is no process to convert this to pure sulfonylcarboxylic acid.

Furthermore, no two-stage synthesis process has become known, which is accessible directly from the salts of 1,3-disulfinato-propane-2-sulfinic acid substituted a-sulfonylcarboxylic acids prepared in situ from allyl sulfonates and hydrogen sulfites in the presence of α-halocarboxylic acids.

Object of the invention

It is the object of the invention to find a simple two-stage synthesis process for the preparation of substituted sulfonylcarboxylic acids from readily available and technically available starting materials, such as sodium allylsulfonate, hydrogen sulfite and a-halocarboxylic acids, which allows the process steps without formation of by-products with simultaneously high purity and yield the target product.

Explanation of the essence of the invention

The object of the invention is to develop a simple two-stage process which makes it possible to economically synthesize t-carboxymethylsulfonyl-propane-I.S-disulfonates.

According to the invention, the object is achieved by reacting allyl sulphonates, preferably sodium allyl sulphonate, of the general formula (II)

in the

M has the abovementioned meaning,

with molar amounts of an α-halocarboxylic acid, preferably α-chlorocarboxylic acid of the general formula (III),

(III)

in the

R has the abovementioned meaning,

and the double molar amount of a Metallhydrogensulfit, preferably sodium bisulfite, in the presence of a catalytic amount of a peroxodisulfate in a first process step and in the subsequent second process step, the resulting reaction solution after addition of a catalytic amount of a soluble in the reaction medium jocid boil until the sulfinate Content of the reacting solution has dropped to practically zero.

The overall reaction, the radically initiated sulfosulfination of the allyl sultonate with coupled carboxyalkylation of the in situ formed salt of 1,3-disulfonato-propane-2-sulfinic acid9 in two process steps, illustrates the following scheme:

2 NaHSO ₃ + Cl. ^ COgH

(ID R

(III)

2. J ~

SO ₃ Na + MaCl + H ₂ O

The sulfosulfination of an allylsulfonate proceeds according to DD 225992 A1 only with maximum yield of Sulfosulfinierungsprodukt when pH conditions are maintained by 2. Adjustment to this pH is achieved by adding a mineral ore to the mixture of allylammonium salt and hydrogen sulfite. Corresponding pH value settings have not hitherto been carried out with an α-halocarboxylic acid. It can therefore be regarded as a surprising finding that, for example, the addition of 1 mole of chloroacetic acid to a mixture of 1 mole of allylsulfonate and 2 moles of sodium bisulfite technical solution gives the optimum starting pH of 2; ie conditions as they correspond to the above objective. The order of combining the reactants is irrelevant to the reaction call.

Depending on the quality of the Nc triumhydrogensulfitlösung used, small pH fluctuations may occur. They are to be corrected by either adding a small amount of a mineral acid or starting the reaction with a partial amount of the halocarboxylic acid and adding the residual amount of the halogenated carboxylic acid only after the first roast step.

For the starting solution prepared in this way, which should have a temperature between 20 and 30 ° C., 1 to 5 mol% peroxodisulfate, based on the allyl sulfonate used, is added to carry out the first process step, in order to trigger the sulfosulfination reaction.

It has proved to be useful to add the peroxodisulfate in zwoi portions to achieve the fullest possible sales, with mostly amounts of 2mdl 2 mol%, based on the allyl sulfonate, are completely sufficient. Suitable peroxodisulfates are sodium, potassium or ammonium peroxodisulfate, which can be used either as a solution or in powder form. The initially pale yellow starting solution turns red to blood-red after the addition of peroxodisulfate, but clearens shortly after passing through the maximum temperature. To initiate the second process step, a catalytic amount of a soluble iodide, for. For example, sodium, potassium or ammonium iodide, optionally iodoacetic acid, added and as long as under boiling cooling further heated until the reaction solution by bromatometric titration of a sample no sulfinate can be detected.

With a starting amount of 5 to 50 mmol of sodium, potassium or ammonium iodide / mol of allylsulfonate complete conversions are achieved over the course of one to two hours. While amounts below 3 mmol of the o.g. Iodides no longer show catalytic activity, larger amounts than 50 mmol accelerate the reaction further; later, however, discolor the crystalline target products significantly.

When the carboxymethylation of the sulfosulfination product is carried out without addition of iodide, the desired reaction takes place in the initial phase, but it slows down as the reaction progresses, so that subsequent reactions do not fail to isolate the desired reaction product, since this too decomposes under continuous thermal stress becomes.

Surprising in this second process step is also the fact that the sulfosulfination product of allylsulfonate, 1,3-disulfonato-propane-2-sulfinic acid can be carboxyalkylated at low pH in the boiling heat, although it is known (W.Jeblick and W.Bunge in "Ullmanns Encyklopadie der technischen Chemie", Vol.22 [1982], p.315) that under such conditions - low pH and high temperatures - sulfinic acids preferentially disproportionate to thiosulforic acid S-esters and sulfonic acids.

On the other hand, it was considered necessary in the prior art to obtain α-sulfonylcarboxylic acids by reacting the metal salts of sulfinic acid or (!) -Halocarboxylic acids, although side reactions such as decarboxylation of the target product could not be ruled out in all cases.

In contrast, in a particular embodiment of the method, it is also possible to carry out the second synthesis step separately. For this purpose, either molar amounts of isolated 1,3-disulfonatopropane-2-sulfinic acid and α-halocarboxylic acid may be added to one mole equivalent of a base or the metal salt of one acid may be reacted with the other acid.

The reaction products thus obtained are identical to those obtained by the two-step synthesis method. This route offers no principal advantage in terms of process, since the necessary starting sulfonates must first be prepared from the allyl sulfonates.

Compared to the Aibeitsweise of the prior art, however, the free a-sulfonylcarboxylic acids are advantageously obtained directly, whereby only the neutralization and after the reaction, the release of the carboxylic acid function is avoided. In addition, side reactions are prevented in this procedure, which is why it must be regarded as much more economical.

In summary, the advantage of the invention in a simple synthesis, which makes directly accessible without the isolation of intermediates, the previously unknown 2-carboxymethylsulfonylmothyl-propane-1,3-disulfonates of the general formula (I) of allylsulfonates. The starting materials used are intermediates which are available on an industrial scale and which can be reacted with simple means in short reaction times. The invention will be explained in more detail by the following examples.

Ausführungsbelsplele example 1

Disodium ^ -carboxymethylsulfonyl-propane-I.S-disulfonate

a) 200 g (1 mol) of 72% technical grade sodium allysulfonate powder containing 25% sodium chloride and 3% sodium sulfate, 539 g (1), in a 1.51 spirit flask fitted with a stirrer, thermometer, reflux condenser and a heating source. 2.02 mol) of 39% technical sodium hydrogen sulfite solution and 118.1 g (1 mol) of 80% aqueous solution of chloroacetic acid and mixed with stirring.

This gives a lemon yellow, completely homogeneous solution of pH 2.15, which is already on dissolution of the sodium allylsulfonate from room temperature to 31 ⁰ C heated. First, 4.56 g (2 mol%) of ammonium peroxodisulfate are added and, another 30 seconds later, another 2 mol% of ammonium peroxydisulfate are added, which triggers the reaction. After only one minute, the reaction temperature maximum of 65'C is reached. To the now blt.troten, clear transparent reaction solution (the red color is caused by iron (lll) -1,3-disulfonato-2-sulfinatopropan, which consists of the reaction intermediate, 1, S-Disulfonato ^ -sulfinato-propane, and the in the technical hydrogen sulfite existing auto salt traces used arises) is added 1.05 g (7 mmol) of sodium iodide and until (2 hours) warmed to reflux at 110 ⁰ C until the content of the intermediate product, 1, S-disulphonato ^ -sulfinato-propane, to zero has fallen off. The sulfinate content is tested by bromatometric titration of a sample of the reaction solution.

The now amber roaction solution contains the target product; the implementation is quantitative. A sample of the reaction solution or a sample of disodium-carboxymethylsulfonyl-propane-IS-disulfonate isolated by storage of the reaction solution in the refrigerator and thus recrystallized from water (F: 229-23ΓΟ show an identical C-NMR spectrum (H ₂ O , external standard tetramothylsilane -TMS, δ = 0.0ppm.) The numbers on the atomic symbols correspond to the chemical shifts of the signals in ppm:

49.6 49.6 53.8

168.2 59.3

On the other hand, a ¹³ C-NMR spectrum recorded in D ₂ O shows that the methylene group between the carboxyl and sulfone groups has a pronounced CH-acidic character, which can be seen by a strong reduction in the intensity of the signal at 59.3 ppm due to H / D exchange is.

b) In a 75ü in! Sulfier flask equipped with a stirrer, thermometer, Rückfhßkühler and a heat source, 388.3 g (1 mol) of trisodium-IS-sulfonato ^ -sulfinatopropan trihydrate, prepared from sodium allylsulfonate and sodium bisulfite according to DD 225991 A1, Example 1 b, 118th , 1 g (1 mol) of 80% aqueous chloroacetic acid, 1.8 g (12 mmol) of sodium iodide and 170 g of water, mixed with stirring and heated. The thick pulp dissolves after reaching the boiling point (113T). Already 15 minutes later, the starting sulfinate can no longer be detected bromatometrically in the virtually colorless solution; d. H. the implementation is over. Already on cooling the reaction solution, the target product begins to crystallize and can be isolated in over 90% yield in crystalline form.

The ¹³ C-NMR spectrum of the resulting crystalline product is completely identical to the product prepared according to Example 1 a.

Example 2

Disodium 2- (1'-carboxyethvlsulfonyl) propane-1,3-disulfonate

The procedure is as described in Example 1, but instead of chloroacetic acid, 2-bromopropionic acid and 5.1 g (34 mmol) of sodium iodide are used for the reaction. Both process variants a) and b) provide identical reaction products which precipitate out of the reaction solution in crystalline form after a relatively long service life. Alcohol wash of the isolated substance gives white crystals;

"C-NMR spectrum (D ₂ O; external standard TMS; δ = 0.0 ppm):

50.2 49.3 57.6

MaO ₃ p

170.9

11.6 The -CH ₂ SO? Na groups are not equivalent, causing signal doubling (49.3 and 50.2 ppm, respectively).

Example 3

Disodium ^ -M 'carboxypropylsulfonyD-propane-I.S-disulfonate

The procedure is as described in Example 1, but instead of chloroacetic acid, 2-bromobutyric acid and 7.5 g (50 mmol) of sodium iodide are used for the reaction. Both variants a) and b) provide identical reaction products which precipitate out of the reaction solution in crystalline form after a relatively long service life, faster after concentration. By alcoholic washing of the isolated substance have been white crystals (hold.

¹³ C-NMR spectrum (D ₂ O, external standard TMS, δ = O.Oppm):

49.9 49.9 57.8

WaO ₃ S

18.9; 21.0

CO ₉ H 170.4

12.5

Claims (2)

claims: 1. Process for the preparation of 2-carboxymethylsulfonyl-propane-1,3-disulfonates of the general formula (I) MO ₃ S ' "SOgM O ₂ S (I)