Organic sulfinate salts, processes for their preparation and use and compositions

Abstract

The application relates to the technical field of organic synthesis, and discloses an organic sulfinate salt composition, a preparation method and application thereof and the composition. The preparation method comprises the following steps: contacting a monovalent organic sulfinate salt shown in formula I with a divalent metal salt or a salt of a metal with a valence higher than two under the condition that a poor solvent exists; the organic sulfinate salt prepared by the method has high yield and high purity, almost no sulfinate salt by-product is generated, the method has the advantages of simple operation, safe and easily-obtained reaction raw materials, rapid reaction, no need of recrystallization, the target product can be obtained through filtration after the reaction, less solvent is used, the cost is low, etc., the composition has the beneficial effects that the composition is more stable than a corresponding sodium salt, the sulfur odor is reduced, the composition has strong reducing capacity, etc.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to an organic sulfinate, its preparation method, applications, and compositions. Background Technology

[0002] Sulfinate derivatives possess excellent reducing properties and are widely used in the coatings, textiles, and paper industries. However, sulfinate derivatives are generally unstable and decompose during storage, processing, and transportation, potentially leading to spontaneous combustion and the release of harmful substances under adverse conditions. Furthermore, the decomposition of sulfinate derivatives reduces the content of sulfuric acid derivatives in the product and releases toxic substances such as sulfur dioxide and / or hydrogen sulfide. In addition, these derivatives are not stable in aqueous solutions, especially in acidic media, thus producing a toxic "sulfur" odor in aqueous or acidic solutions while significantly reducing their reducing power. In contrast, polyvalent metal salts of sulfinates, due to their increased binding energy between metal ions and oxygen atoms, inhibit decomposition and thus exhibit strong stability in aqueous solutions.

[0003] CN100347154C discloses sulfinic acid derivatives, their preparation, and uses. This compound can form redox systems with common oxidants and is used in the primary and / or post-polymerization of emulsion polymers. As a reducing agent, this compound can reduce the residual monomer content to an acceptable level. Simultaneously, it contains no formaldehyde and does not generate formaldehyde during the reaction, making it suitable for the synthesis of low-VOC emulsions. However, the sulfinating agent zinc dithionite in the disclosed technical solution is prone to decomposition when exposed to air, and the raw materials are hazardous chemicals such as zinc powder and sulfur dioxide, requiring on-site preparation and use, making the operation complex. Therefore, there is an urgent need to study a new method for synthesizing organic sulfinate compositions, which is of great significance to the development of the coatings, textiles, and papermaking industries. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low yield and purity of organic sulfinates, a large number of sulfonate byproducts, poor stability of organic sulfinate compositions, and strong sulfur odor in the existing technology, and to provide an organic sulfinate, its preparation method, application and composition.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing an organic sulfinate, characterized in that the method comprises: reacting a monovalent organic sulfinate of Formula I with a divalent or higher metal salt in the presence of a poor solvent;

[0006]

[0007] Among them, R 1 It is an H or C1-C6 hydrocarbon group, R 2It is H or C1-C6 alkyl or M', where M and M' are the same or different and are each independently selected from NH4 or monovalent metal ions;

[0008] The unsuitable solvent is selected from solvents whose solubility for the monovalent organic sulfinate at 25°C is less than 0.01 g / 100 mL.

[0009] The second aspect of the present invention provides an organic sulfinate prepared by the method described in the first aspect of the present invention.

[0010] The third aspect of the present invention provides the application of the method described in the second aspect of the present invention in improving the yield and purity of organic sulfinates.

[0011] A fourth aspect of the present invention provides an organic sulfinate composition, characterized in that the composition comprises a monovalent organic sulfinate of formula I and a compound of formula II;

[0012]

[0013] Where s is selected from 1-3, and t is selected from 1-7;

[0014] R 1 and R 2 The definition is the same as that described in the first aspect of this invention;

[0015] The molar ratio of the monovalent organic sulfinate shown in Formula I to the compound shown in Formula II is 0.1-10:1.

[0016] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0017] The organic sulfinate composition provided by this invention is more stable than the corresponding sodium salt, has a reduced sulfur odor, and also has a strong reducing ability. The organic sulfinate composition prepared by the provided method has high yield and purity, produces almost no sulfonate byproducts, and has the advantages of simple operation, safe and readily available reaction raw materials, rapid reaction, no need for recrystallization, and the target product can be obtained by filtration after the reaction. It also uses less solvent and has low cost. Attached Figure Description

[0018] Figure 1 The results show the stability test results of sulfinates and their compositions at pH=5. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] As mentioned above, the first aspect of the present invention provides a method for preparing an organic sulfinate, characterized in that the method comprises: reacting a monovalent organic sulfinate of Formula I with a divalent or higher metal salt in the presence of a poor solvent;

[0021]

[0022] Among them, R 1 It is an H or C1-C6 hydrocarbon group, R 2 It is H or C1-C6 alkyl or M', where M and M' are the same or different and are each independently selected from NH4 or monovalent metal ions;

[0023] The unsuitable solvent is selected from solvents whose solubility for the monovalent organic sulfinate at 25°C is less than 0.01 g / 100 mL.

[0024] In some embodiments of the present invention, preferably, R 1 It is an H or C1-C3 hydrocarbon group.

[0025] In some embodiments of the present invention, preferably, R 2 It is H or C1-C6 straight-chain alkyl or M'.

[0026] In some embodiments of the present invention, preferably, M and M' are each independently selected from monovalent metal ions.

[0027] In some embodiments of the present invention, preferably, R 1 It is an H or C2-C3 alkyl group.

[0028] In some embodiments of the present invention, preferably, R 2 It is H or C1-C3 straight-chain alkyl or M'.

[0029] In some embodiments of the present invention, preferably, M and M' are each independently selected from alkali metal ions.

[0030] In some embodiments of the present invention, preferably, the monovalent organic sulfinate is selected from at least one of disodium 2-hydroxy-2-sulfinate, disodium 2-hydroxy-2-sulfinate propionate, sodium ethyl 2-hydroxy-2-sulfinate propionate, sodium 2-hydroxyphenylhydroxymethylsulfinate, sodium 4-methoxyphenylhydroxymethylsulfinate, dipotassium 2-hydroxy-2-sulfinate, dipotassium 2-hydroxy-2-sulfinate propionate, potassium ethyl 2-hydroxy-2-sulfinate propionate, potassium 2-hydroxyphenylhydroxymethylsulfinate, and potassium 4-methoxyphenylhydroxymethylsulfinate, and more preferably selected from disodium 2-hydroxy-2-sulfinate and / or dipotassium 2-hydroxy-2-sulfinate.

[0031] In some embodiments of the present invention, preferably, the divalent or higher metal salt is selected from divalent or higher inorganic metal salts, more preferably from at least one divalent or higher inorganic salt selected from alkaline earth metals, Group III metals and transition metals, further preferably from at least one inorganic salt selected from aluminum, calcium, iron, magnesium, manganese, tungsten and zinc, and more preferably from at least one inorganic salt selected from aluminum, magnesium and zinc.

[0032] In some embodiments of the present invention, preferably, the anion of the divalent or higher metal salt is selected from at least one of chloride ion, sulfate ion, sulfite ion and acetate ion.

[0033] In some embodiments of the present invention, preferably, the undesirable solvent is selected from at least one of methanol, ethanol, acetonitrile and acetone, and more preferably from methanol and / or ethanol.

[0034] In some embodiments of the present invention, preferably, the reaction is carried out in the presence of a good solvent.

[0035] In some embodiments of the present invention, preferably, the good solvent is water.

[0036] In some embodiments of the present invention, preferably, the molar ratio of the poor solvent to the good solvent is 1-20:1, which can be any value within this molar ratio range or a range between any two values. For example, it can be any value or a range between any two values ​​from 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, and 20:1.

[0037] In some embodiments of the present invention, preferably, the molar ratio of the divalent or higher metal salt to the monovalent organic sulfinate is 0.1-3:1, which can be any value within the range of this molar ratio or a range between any two values.

[0038] In some embodiments of the present invention, preferably, the molar ratio of the poor solvent to the monovalent organic sulfinate compound is 10-50:1, which can be any value within this molar ratio range or a range between any two values.

[0039] In some embodiments of the present invention, preferably, the temperature of the reaction is 0-60°C, which can be any value in this temperature range or a range between any two values. For example, it can be any value or a range between any two values ​​of 0, 10, 20, 30, 40, 50 and 60.

[0040] In some embodiments of the present invention, preferably, the reaction time is 0.5-8 hours, which can be any value within this time range or a range between any two values. For example, it can be any value or a range between any two values ​​from 0.5, 1, 2, 3, 4, 5, 6, 7 and 8.

[0041] In this invention, the reaction system obtained after the reaction is completed can be separated into solid and liquid phases to obtain the final product, a compound represented by formula II.

[0042]

[0043] In this invention, s is selected from 1-3, and t is selected from 1-7.

[0044] The preparation method of the compound described in this invention is applicable to both continuous reaction processes and batch reaction processes.

[0045] In some embodiments of the present invention, preferably, the method for preparing the monovalent organic sulfinate of Formula I includes: contacting the compound of Formula A with the compound of Formula B to carry out a nucleophilic addition reaction.

[0046]

[0047] Wherein, R1 is selected from H or C1-C6 alkyl, and R2 is selected from H, C1-C6 alkyl, or M. 1 ;

[0048] R3 and R4 are each independently H or C1-C6 alkyl groups;

[0049] M 1 Selected from NH4 or monovalent metal cations;

[0050] In some embodiments of the present invention, preferably, R1 is selected from H or C1-C5 alkyl groups.

[0051] In some embodiments of the present invention, preferably, R2 is selected from H, C1-C3 alkyl groups, or M. 1 .

[0052] In some embodiments of the present invention, preferably, R3 and R4 are each independently H or C1-C3 alkyl.

[0053] In some embodiments of the present invention, preferably, M 1 Selected from monovalent metal cations.

[0054] In some embodiments of the present invention, preferably, R1 is selected from H or C1-C3 alkyl groups.

[0055] In some embodiments of the present invention, preferably, R2 is selected from H, methyl, ethyl, or M. 1 .

[0056] In some embodiments of the present invention, preferably, R3 and R4 are each independently H, methyl or ethyl.

[0057] In some embodiments of the present invention, preferably, M 1 Selected from sodium ions or potassium ions.

[0058] In some embodiments of the present invention, preferably, the nucleophilic reaction is carried out in the presence of a basic substance.

[0059] In some embodiments of the present invention, preferably, the alkaline substance is selected from at least one of hydroxides, carbonates, bicarbonates, basic carbonates and metal oxides, and more preferably from at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, lithium hydroxide, lithium carbonate, lithium bicarbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium bicarbonate, calcium oxide, calcium hydroxide, calcium carbonate, calcium bicarbonate, zinc oxide, zinc hydroxide, zinc carbonate, aluminum oxide, aluminum hydroxide and basic aluminum carbonate.

[0060] In some embodiments of the present invention, preferably, the alkaline substance is selected from at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

[0061] In some embodiments of the present invention, preferably, the reaction is carried out in the presence of a solvent.

[0062] In some embodiments of the present invention, preferably, the solvent is water.

[0063] In some embodiments of the present invention, preferably, the molar ratio of the alkaline substance to the compound represented by formula A is 1-4.5:1, more preferably 2-2.6:1.

[0064] In some embodiments of the present invention, preferably, the molar ratio of the compound represented by formula B to the compound represented by formula A is 0.5-3.5:1, more preferably 0.8-2:1.

[0065] In some embodiments of the present invention, preferably, the conditions for the nucleophilic reaction include: a temperature of 0-90°C, preferably 10-50°C; and a time of 0.5-8h, preferably 1-6h.

[0066] In this invention, the reaction system obtained after the nucleophilic addition reaction can be separated and purified by cooling, filtration, recrystallization and drying to obtain the final product, the compound shown in Formula I.

[0067]

[0068] In some embodiments of the present invention, preferably, the cooling is to reduce the reaction system to 20-30°C.

[0069] In some embodiments of the present invention, preferably, the recrystallization temperature is -10 to 80°C.

[0070] In some embodiments of the present invention, preferably, the drying temperature is 40-65°C.

[0071] In some embodiments of the present invention, the recrystallization process can be carried out in a Y-type mixer.

[0072] The preparation method of the compound described in this invention is applicable to both continuous reaction processes and batch reaction processes.

[0073] In this invention, the reaction can be carried out in a microreactor.

[0074] The second aspect of the present invention provides an organic sulfinate prepared by the method described in the first aspect of the present invention.

[0075] The third aspect of the present invention provides the application of the method described in the first aspect of the present invention in improving the yield and purity of organic sulfinates.

[0076] A fourth aspect of the present invention provides an organic sulfinate composition, characterized in that the composition comprises a monovalent organic sulfinate of formula I and a compound of formula II;

[0077]

[0078] Where s is selected from 1-3, and t is selected from 1-7;

[0079] R 1 and R 2 The definition is the same as that described in the first aspect of this invention;

[0080] The molar ratio of the monovalent organic sulfinate shown in Formula I to the compound shown in Formula II is 0.1-10:1.

[0081] In some embodiments of the present invention, preferably, the molar ratio of the monovalent organic sulfinate represented by Formula I to the compound represented by Formula III is 0.2-5:1, preferably any value or a range between any two values ​​from 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 2:1, 3:1, 4:1 and 5:1.

[0082] The present invention will be described in detail below through examples. In the following examples, the yield of the organic sulfinate composition is calculated using the formula: Organic sulfinate composition yield = Actual mass / Theoretical mass × 100%; the purity of the organic sulfinate is calculated by iodine reduction titration; the content of each component in the organic sulfinate composition is obtained by ICP testing; reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through commercial channels.

[0083] Preparation Example 1

[0084] 110 mmol of thiourea dioxide was weighed and added to 5 mol of deionized water. 100 mmol of 50% glyoxylic acid solution was added dropwise, and the mixture was kept at 25°C. 225 mmol of 50% sodium hydroxide solution was then added dropwise. After the addition was complete, the temperature was raised to 30°C and reacted for 4 hours. After the reaction was complete, the temperature was restored to 25°C, and the mixture was filtered to obtain a crude solid product. The solid was recrystallized from water and methanol to obtain disodium 2-hydroxy-2-sulfinate acetate. The yield of disodium 2-hydroxy-2-sulfinate acetate was 82.6%, and the purity of the target product was calculated to be 73.2% by iodine reduction titration. No disodium 2-hydroxy-2-sulfinate acetate byproduct was detected by NMR spectroscopy.

[0085] Preparation Example 2

[0086] 150 mmol of thiourea dioxide was weighed and added to 3 mol of deionized water. 100 mmol of a 50% (w / w) pyruvate aqueous solution was added dropwise, maintaining the temperature at 20°C. 250 mmol of a 50% (w / w) sodium hydroxide solution was then added dropwise. After the addition was complete, the temperature was raised to 50°C and reacted for 2 hours. The temperature was then lowered back to 20°C, and the mixture was filtered to obtain a crude solid product. The solid was recrystallized from water and methanol to obtain disodium 2-hydroxy-2-sulfinic acid propionate. The yield of disodium 2-hydroxy-2-sulfinic acid acetate was 72.6%, and the purity of the target product was calculated to be 68.2% by iodine reduction titration. No disodium 2-hydroxy-2-sulfinic acid acetate byproduct was detected by NMR spectroscopy.

[0087] Example 1

[0088] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 20 mmol of zinc sulfite, add a mixture of deionized water (50 mmol) and methanol (300 mmol), and react at 25 °C for 4 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0089] The yield of the composition was 91.2%, and the purity of the organic sulfinate was 90.6% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 36.8 mol% sodium salt and 63.2 mol% zinc salt.

[0090] Example 2

[0091] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 10 mmol of zinc sulfate heptahydrate, add a mixture of deionized water (50 mmol) and methanol (300 mmol), and react at 25 °C for 4 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0092] The yield of the composition was 88.4%, and the purity of the organic sulfinate was 79.5% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 52.1 mol% sodium salt and 47.9 mol% zinc salt.

[0093] Example 3

[0094] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 5 mmol of zinc chloride, add a mixture of deionized water (50 mmol) and methanol (300 mmol), and react at 25 °C for 4 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0095] The yield of the composition was found to be 85.6%, and the purity of the organic sulfinate was calculated to be 77.4% by iodine reduction titration. ICP testing revealed that the composition contained 65.2 mol% sodium salt and 34.8 mol% zinc salt.

[0096] Example 4

[0097] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 40 mmol of zinc sulfite, add a mixture of deionized water (50 mmol) and methanol (300 mmol), and react at 50 °C for 2 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0098] The yield of the composition was 93.8%, and the purity of the organic sulfinate was 76.5% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 22.2 mol% sodium salt and 77.8 mol% zinc salt.

[0099] Example 5

[0100] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 2.5 mmol of zinc sulfite, add a mixture of deionized water (50 mmol) and methanol (500 mmol), and react at 25 °C for 4 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0101] The yield of the composition was 94.2%, and the purity of the organic sulfinate was 67.6% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 81.3 mol% sodium salt and 18.7 mol% zinc salt.

[0102] Example 6

[0103] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 5 mmol of zinc sulfite, add a mixture of deionized water (50 mmol) and ethanol (300 mmol), and keep the reaction at 10 °C for 6 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and zinc 2-hydroxy-2-sulfinate acetate.

[0104] The yield of the composition was 66.2%, and the purity of the organic sulfinate was 50.8% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 67.5 mol% sodium salt and 32.5 mol% zinc salt.

[0105] Example 7

[0106] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinate acetate from Preparation Example 1, weigh 5 mmol of magnesium chloride hexahydrate, add a mixture of deionized water (50 mmol) and methanol (300 mmol), and react at 25 °C for 4 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinate acetate and magnesium 2-hydroxy-2-sulfinate acetate.

[0107] The yield of the composition was 80.8%, and the purity of the organic sulfinate was 78.7% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 66.6 mol% sodium salt and 33.4 mol% magnesium salt.

[0108] Example 8

[0109] Weigh 10 mmol of disodium 2-hydroxy-2-sulfinic acid propionate from Preparation Example 2, weigh 5 mmol of anhydrous aluminum chloride, add a mixture of deionized water (50 mmol) and methanol (200 mmol), and keep the reaction at 40 °C for 8 h; filter to obtain a solid product consisting of disodium 2-hydroxy-2-sulfinic acid propionate and aluminum 2-hydroxy-2-sulfinic acid propionate.

[0110] The yield of the composition was 30.9%, and the purity of the organic sulfinate was 31.4% as calculated by iodine reduction titration. ICP testing revealed that the composition contained 63.3 mol% sodium salt and 36.7 mol% aluminum salt.

[0111] Comparative Example 1

[0112] Weigh 6.54 g of zinc powder, add deionized water, and pass sulfur dioxide through to produce zinc dithionite. Add 27.2 g of 50% glyoxylic acid solution dropwise. After the exothermic reaction is complete, add 15 g of zinc oxide. Precipitate the crude product present in the filtrate with methanol.

[0113] The yield of the obtained product, zinc 2-hydroxy-2-sulfinate, was 31.8%, and the purity of the organic sulfinate was calculated to be 20.6% by iodine reduction titration. NMR spectroscopy revealed a zinc sulfonate byproduct content of 48.9%.

[0114] Test Example 1

[0115] The stability of the salt solution

[0116] The change in sulfinate content over time in a 10 wt% solution containing the following salts was determined by iodine reduction titration:

[0117] A) Disodium salt of 2-hydroxy-2-sulfinic acid acetate;

[0118] B) Zinc acetate of 2-hydroxy-2-sulfinic acid;

[0119] C) The mixture of disodium 2-hydroxy-2-sulfinic acid acetate and zinc 2-hydroxy-2-sulfinic acid acetate from Example 1;

[0120] D) The mixture of disodium 2-hydroxy-2-sulfinic acid acetate and zinc 2-hydroxy-2-sulfinic acid acetate from Example 2;

[0121] E) The mixture of disodium 2-hydroxy-2-sulfinic acid acetate and zinc 2-hydroxy-2-sulfinic acid acetate in Example 3;

[0122] F) The mixture of disodium 2-hydroxy-2-sulfinate acetate and magnesium 2-hydroxy-2-sulfinate acetate of Example 7;

[0123] G) The mixture of disodium 2-hydroxy-2-sulfinic acid propionate and aluminum 2-hydroxy-2-sulfinic acid propionate of Example 8.

[0124] For comparison, the values ​​of solutions A) and B) were measured at pH 9, the pH value generated when the sodium salt was dissolved in water. The pH of solutions A) and B) was adjusted to 5 using dilute sulfuric acid. The results are as follows... Figure 1 As shown, Na-Zn, Na-Mg, and Na-Al salts exhibit improved stability compared to their corresponding sodium salts. Due to their higher stability, they possess strong and stable reducing power. The organic sulfinate compositions prepared in Examples 4-6 also achieved experimental results comparable to solutions C)-G) under the conditions of this test example, thus their solution stability is significantly better than solutions A) and B).

[0125] Test Example 2

[0126] Determination of sulfur odor

[0127] The reducing agent was provided as a solid and as a 20 wt% solution or suspension. Odor was determined by a panel of five testers and evaluated according to the grading in Table 1. The reducing agent was the salt solution given in Test Example 1 or a solid salt thereof. The results are given in Table 2.

[0128] Table 1

[0129]

[0130]

[0131] Table 2

[0132]

[0133] The compositions of this invention produce a slight sulfur odor, while the sodium salt has a very strong sulfur odor. This confirms the results given in Test Example 1, and the organic sulfinate compositions prepared in Examples 4-6 can also achieve experimental results comparable to C)-G) under the conditions of this test example.

[0134] The results above show that the method of the present invention reacts organic sulfinate compounds with inorganic zinc salts in the presence of unfavorable solvents to generate zinc sulfinate compounds. The yield and purity are high, and almost no sulfonate byproducts are produced. It also has the advantages of simple operation, safe and readily available raw materials, rapid reaction, no need for recrystallization, and the target product can be obtained by filtration after the reaction. It uses less solvent and has low cost. Furthermore, the composition is more stable than the corresponding sodium salt, has a reduced sulfur odor, and also has a strong reducing ability.

[0135] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing an organic sulfinate, characterized in that, The method includes reacting a monovalent organic sulfinate of Formula I with a divalent or higher metal salt in the presence of a poor solvent; Among them, R 1 It is an H or C1-C6 hydrocarbon group, R 2 It is H or C1-C6 alkyl or M', where M and M' are the same or different and are each independently selected from NH4 or monovalent metal ions; The unsuitable solvent is selected from solvents whose solubility for the monovalent organic sulfinate at 25°C is less than 0.01 g / 100 mL.

2. The method according to claim 1, wherein, R 1 It is an H or C1-C3 hydrocarbon group; And / or, R 2 It is H or a C1-C6 straight-chain alkyl group or M'; And / or, M and M' are each independently selected from monovalent metal ions.

3. The method according to claim 2, wherein, R 1 It is an H or C2-C3 alkyl group; And / or, R 2 It is H or C1-C3 straight-chain alkyl or M'; And / or, M and M' are each independently selected from alkali metal ions.

4. The method according to any one of claims 1-3, wherein, The monovalent organic sulfinate is selected from at least one of disodium 2-hydroxy-2-sulfinic acid acetate, disodium 2-hydroxy-2-sulfinic acid propionate, sodium ethyl 2-hydroxy-2-sulfinic acid propionate, sodium 2-hydroxyphenylhydroxymethyl sulfinate, sodium 4-methoxyphenylhydroxymethyl sulfinate, dipotassium 2-hydroxy-2-sulfinic acid acetate, dipotassium 2-hydroxy-2-sulfinic acid propionate, potassium ethyl 2-hydroxy-2-sulfinic acid propionate, potassium 2-hydroxyphenylhydroxymethyl sulfinate, and potassium 4-methoxyphenylhydroxymethyl sulfinate, preferably selected from disodium 2-hydroxy-2-sulfinic acid acetate and / or dipotassium 2-hydroxy-2-sulfinic acid acetate.

5. The method according to any one of claims 1-4, wherein, The divalent or higher metal salt is selected from divalent or higher inorganic metal salts, preferably from at least one of alkaline earth metals, Group III metals and transition metals, and more preferably from at least one of aluminum, calcium, iron, magnesium, manganese, tungsten and zinc. Preferably, the anion of the divalent or higher metal salt is selected from at least one of chloride ion, sulfate ion, sulfite ion and acetate ion.

6. The method according to any one of claims 1-5, wherein, The undesirable solvent is selected from at least one of methanol, ethanol, acetonitrile and acetone, preferably selected from methanol and / or ethanol; Preferably, the reaction is carried out in the presence of a good solvent; Preferably, the good solvent is water; Preferably, the molar ratio of the poor solvent to the good solvent is 1-20:

1.

7. The method according to any one of claims 1-6, wherein, The molar ratio of the divalent or higher metal salt to the monovalent organic sulfinate is 0.1-3:

1.

8. The method according to any one of claims 1-7, wherein, The molar ratio of the undesirable solvent to the monovalent organic sulfinate compound is 10-50:

1.

9. The method according to any one of claims 1-8, wherein, The reaction temperature is 0-60℃; Preferably, the reaction time is 0.5-8 hours.

10. The organic sulfinates prepared by the method according to any one of claims 1-9.

11. The application of the method according to any one of claims 1-9 in improving the yield and purity of organic sulfinates and reducing sulfonate byproducts.

12. An organic sulfinate composition, characterized in that, The composition comprises a monovalent organic sulfinate of Formula I and a compound of Formula III; Where s is selected from 1-3, and t is selected from 1-7; R 1 and R 2 The definition is the same as that described in any one of claims 1-3; The molar ratio of the monovalent organic sulfinate shown in Formula I to the compound shown in Formula III is 0.1-10:

1.

13. The composition according to claim 12, wherein, The molar ratio of the monovalent organic sulfinate shown in Formula I to the compound shown in Formula III is 0.2-5:1.

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