A kind of disulfonate and its preparation method and application

Abstract

The present invention provides a double taurate, a preparation method and an application thereof, relating to the field of surfactant preparation; the preparation method is as follows: (1) reacting a fatty acid and / or an oil and fat with an alkali metal salt of taurine to obtain a reaction product containing N-acyl taurate; (2) directly reacting the reaction product obtained in step (1) with dimethyl carbonate without separation and purification to obtain N-acyl taurate and N-acyl methyl taurate. The present invention also provides the prepared double taurate and its application in the preparation of a highly foaming surfactant. Compared with the prior art, the present invention avoids the use of fatty acyl chloride and N-methyl taurate which have high use costs and simultaneously have safety and environmental protection hazards. At the same time, by using a one-pot continuous reaction, it is also possible to effectively directly obtain the double taurate with the expected mixing ratio, further improving the reaction efficiency, avoiding caking, and improving the usability of the double taurate.

Description

Technical Field

[0001] The present invention relates to the field of surfactant preparation, and specifically relates to a bis-taurinate and its preparation method and application. Background Art

[0002] N-acyl taurinate surfactants have been widely used due to their extremely low irritation, non-toxicity, and easy biodegradability. This type of surfactant has good compatibility with anionic, non-ionic, and amphoteric surfactants. It is a highly safe anionic surfactant with excellent water solubility, hard water resistance, alkali resistance, and acid resistance.

[0003] Generally, the N-acyl taurinate surfactants on the market are mainly N-acyl methyl taurinates. Currently, the industrial production of N-acyl methyl taurinates mostly adopts the Schotten-Baumann condensation process with acyl chloride as the main raw material, that is: fatty acyl chloride and N-methyl taurinate undergo an amidation reaction in water / organic solvent under alkaline conditions. This process has two problems:

[0004] 1. Using acyl chloride as the raw material introduces a large amount of chloride ions. A large amount of chlorine-containing wastewater will be generated in the subsequent desalting step, with poor environmental protection; acyl chloride belongs to dangerous materials, with poor safety; moreover, the synthesis of fatty acyl chloride increases a lot of costs, with poor economy.

[0005] 2. The preparation method of sodium N-methyl taurinate is: first, ethylene oxide reacts with sodium bisulfite to generate sodium 2-hydroxyethyl sulfonate, and then reacts with methylamine at high temperature and high pressure to generate sodium N-methyl taurinate; this method is carried out at a high temperature of 150 - 300 °C and a high pressure of 10 - 25 Mpa. The process conditions are harsh. At the same time, due to the use of methylamine, which is a gas at room temperature, there are problems in terms of its raw material source, environmental protection, and labor protection, with the disadvantages of poor environmental protection, poor safety, and poor economy.

[0006] To solve the problem of fatty acyl chloride, some researchers have tried the direct amidation condensation process with fatty acid as the main raw material, that is, fatty acid and sodium methyl taurinate are dehydrated and condensed under high temperature conditions to directly synthesize the target product in one step. For example, patents US5496959 / US2880219 / JP2002234868 / US3232968 / CN105175291 / CN201510568940.5 / CN115160189, etc. describe the direct condensation process of fatty acid and sodium methyl taurinate, but they still cannot solve the problem of sodium N-methyl taurinate.

[0007] Patent CN102875422 uses dimethyl sulfate to methylate N-acyl taurine sodium to produce N-acyl methyl taurine sodium, in which fatty acyl chloride is used. At the same time, the nature of the action of dimethyl sulfate is similar to that of phosgene, belonging to a controlled reagent, with poor safety and relatively high separation costs in the later stage.

[0008] In the previous research of the applicant of the present invention, it was found that the "double taurine salt" mixed surfactant combination of N-acyl taurine salt and N-acyl methyl taurine salt has better performance than any one of the individual surfactants, and a patent has been applied for, which is specifically described in Patent CN116098821A.

[0009] Although the preparation of the "double taurine salt" surfactant can be achieved by the method of separately producing two N-acyl taurine salts through the aforementioned method, it inevitably has problems of poor environmental protection, poor safety and poor economy.

[0010] Therefore, how to provide a simple, highly environmentally friendly, highly safe and economically good preparation method for "double taurine salts" is one of the key research issues for those skilled in the art. Summary of the Invention

[0011] In view of the problems of poor environmental protection, poor safety and poor economy in the preparation process of N-acyl taurine salt and N-acyl methyl taurine salt existing in the prior art, the present invention provides a double taurine salt and its preparation method. First, fatty acid and taurine salt are directly amidated to synthesize N-acyl taurine salt, and then dimethyl carbonate is used to methylate N-acyl taurine salt, so that "double taurine salts" mixed with N-acyl taurine salt and N-acyl methyl taurine salt in various proportions can be generated in one reactor according to requirements; at the same time, the applicant unexpectedly found in the research process of the preparation method that using the preparation method of the present invention can effectively reduce the dissolution temperature of the surfactant system composed of the prepared double taurine salts.

[0012] In the present invention, "double taurine salt" refers to N-acyl taurine salt and N-acyl methyl taurine salt, which refers to the type of compound rather than the compound itself, and is subject to the specifically prepared double taurine salt in the technical solution of the present invention.

[0013] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0014] A preparation method of double taurine salt, comprising the following steps:

[0015] (1) React fatty acid and / or oil with an alkali metal salt of taurine to obtain a reaction product containing N-acyl taurine salt;

[0016] (2) Without separation and purification, the reaction product obtained in step (1) is directly reacted with dimethyl carbonate to obtain N-acyl taurate and N-acyl methyl taurate.

[0017] Preferably, the reaction route of step (1) is as follows:

[0018]

[0019] In the formula, R is a saturated or unsaturated hydrocarbon group with 7 to 21 carbon atoms; M is selected from lithium ion, potassium ion or sodium ion among alkali metal ions.

[0020] Preferably, the reaction route of step (2) is as follows:

[0021]

[0022] In the formula, R is a saturated or unsaturated hydrocarbon group with 7 to 21 carbon atoms; M is selected from lithium ion, potassium ion or sodium ion among alkali metal ions.

[0023] Preferably, the catalyst for the reaction in step (1) is one or more of hydroxides, phosphates, phosphites, hypophosphites, carbonates, sulfates, methoxy salts, ethoxy salts and oxides of alkali metals or alkaline earth metals.

[0024] Most preferably, the mass ratio of the catalyst for the reaction in step (1) to fatty acid and / or oil is 1:200 - 330;

[0025] Preferably, the mass ratio of the fatty acid and / or oil to the alkali metal salt of taurine in step (1) is 2 - 5:1 - 3.

[0026] Preferably, the fatty acid in step (1) is selected from one or more of caprylic acid, capric acid, lauric acid, coconut fatty acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, isostearic acid, nonadecanoic acid, arachidic acid, behenic acid, α-undecenoic acid, oleic acid, linoleic acid, ricinoleic acid and arachidic acid.

[0027] Further preferably, the fatty acid is selected from coconut fatty acid and / or lauric acid.

[0028] Preferably, the oil in step (1) is selected from natural vegetable oils and / or animal oils.

[0029] Further preferably, the vegetable oil is selected from one or more of olive oil, castor oil, peanut oil, coconut oil, soybean oil, cottonseed oil, linseed oil, palm oil and corn oil; the animal oil is selected from beef tallow.

[0030] Most preferably, the vegetable oil is coconut oil.

[0031] Preferably, the alkali metal in the alkali metal salt in step (1) is selected from one or more of lithium, sodium and potassium.

[0032] More preferably, the alkali metal in the alkali metal salt in step (1) is selected from sodium.

[0033] Preferably, the reaction medium for the reaction in step (1) is selected from one or more of methanol, ethanol, isopropanol, acetone, ethyl acetate, propylene glycol, glycerol, ethylene glycol and polyethylene glycol.

[0034] More preferably, the reaction medium is selected from one or more of propylene glycol and glycerol.

[0035] Most preferably, the mass of the reaction medium in step (1) accounts for 0-99% of the total mass of all substances in the reaction system in step (1).

[0036] Preferably, the conditions for the reaction in step (1) are: temperature is 150-200 °C, and time is 2-8 h.

[0037] Preferably, the conditions for the reaction in step (2) are: reflux reaction for 1-2 h.

[0038] The present invention also provides the ditaurate salt prepared by the above preparation method.

[0039] The present invention also provides the application of the above ditaurate salt in the preparation of a surfactant with high foaming performance.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention directly uses fatty acids and / or oils and taurate salts for amidation reaction, and then conducts methylation reaction with dimethyl carbonate, avoiding the use of fatty acyl chlorides and N-methyl taurate salts with high usage costs and potential safety and environmental protection hazards, and can effectively reduce the dissolution temperature of the surfactant system containing the prepared ditaurate salt, and can maintain a liquid state within a wider temperature range, improving the usability of the ditaurate salt. At the same time, using the one-pot continuous reaction can also effectively and directly obtain the ditaurate salt with the expected mixing ratio, further improving the reaction efficiency and reducing the production cost of the product.

[0042] (2) At the same time, the inventors unexpectedly found that the ditaurate salt prepared by the present invention has better foaming property and milder detergency at low dosages compared to the ditaurate salt obtained by mixing conventional commercially available products. Detailed Embodiments

[0043] It should be noted that the raw materials used in the present invention are all ordinary commercially available products, and no specific limitation is imposed on their sources.

[0044] Example 1

[0045] Charge 200 g of lauric acid, 150 g of sodium taurate, 1 g of sodium hydroxide, and 150 g of propylene glycol into a reaction flask equipped with a stirrer, a condenser, and a feed funnel. Under nitrogen protection, heat the mixture to 190 °C and keep heating and stirring for 2 hours; cool down to 110 °C, and dropwise add 100 g of dimethyl carbonate with stirring. After the addition is complete, keep refluxing for 1 hour, and then distill out the residual solvent at 110 °C and then discharge the product.

[0046] The final product contains: sodium N-lauroylmethyl taurate: 329 g, sodium N-lauroyl taurate: 15 g.

[0047] Example 2

[0048] Charge 200 g of lauric acid, 300 g of sodium taurate, 1 g of sodium hydroxide, and 150 g of propylene glycol into a reaction flask equipped with a stirrer, a condenser, and a feed funnel. Under nitrogen protection, heat the mixture to 190 °C and keep heating and stirring for 2 hours; cool down to 110 °C, and dropwise add 45 g of dimethyl carbonate with stirring. After the addition is complete, keep refluxing for 1 hour, and then distill out the residual solvent at 110 °C and then discharge the product.

[0049] The final product contains: sodium N-lauroylmethyl taurate: 172 g, sodium N-lauroyl taurate: 166 g.

[0050] Example 3

[0051] Charge 330 g of coconut oil, 80 g of sodium taurate, 1 g of calcium oxide, and 80 g of glycerol into a reaction flask equipped with a stirrer, a condenser, and a feed funnel. Under nitrogen protection, heat the mixture to 150 °C and keep heating and stirring for 7 hours; add 20 g of dimethyl carbonate dropwise with stirring. After the addition is complete, keep refluxing for 2 hours, and then distill out the residual solvent and then discharge the product.

[0052] The final product contains: sodium N-cocoyl methyl taurate: 71 g, sodium N-cocoyl taurate: 89 g.

[0053] Example 4

[0054] Charge 400 g of coconut fatty acid, 80 g of sodium taurate, 1 g of sodium hydroxide, and 0.5 g of sodium hypophosphite into a reaction flask equipped with a stirrer, a condenser, and a feed funnel. Under nitrogen protection, heat the mixture to 200 °C and keep heating and stirring for 8 hours; cool down to 120 °C, and dropwise add 10 g of dimethyl carbonate with stirring. After the addition is complete, keep refluxing for 1 hour, and then distill out the residual solvent and then discharge the product.

[0055] The final product contains: sodium N-cocoyl methyl taurate: 35 g, sodium N-cocoyl taurate: 152 g.

[0056] Example 5

[0057] Charge 300 g of coconut fatty acid, 80 g of sodium taurate, 1 g of sodium hydroxide, and 0.5 g of sodium hypophosphite into a reaction flask equipped with a stirrer, a condenser, and a feeding funnel. Under the protection of nitrogen, heat the mixture to 200 °C and keep heating and stirring for 8 hours; cool down to 120 °C, and dropwise add 60 g of dimethyl carbonate with stirring. After the addition is completed, keep refluxing for 1 hour, and then distill out the residual solvent and discharge the product.

[0058] The final product contains: 153 g of sodium N-cocoyl methyl taurate and 12 g of sodium N-cocoyl taurate.

[0059] Effect Example 1 Performance test of the paste of the ditaurate prepared in Examples 1-5 in the preparation of cleaning compositions

[0060] The detection methods used in this effect example are as follows:

[0061] Appearance (25 °C): Place the sample at 25 °C and visually observe whether it forms a paste after maintaining the temperature for 48 hours.

[0062] Appearance (10 °C): Place the sample at 10 °C and visually observe whether it forms a paste after maintaining the temperature for 48 hours.

[0063] Dissolution temperature: Place the sample at -18 °C to form a paste, then keep the temperature at 0 °C for 24 hours, and then heat it at a rate of 5 °C / hour to observe the dissolution temperature and record the complete dissolution temperature.

[0064] Paste spreadability at 25 °C: Place the sample at 25 °C and maintain the temperature for 48 hours. Then, extrude 1 g of the sample onto a wet hand and rub it 10 times. Observe whether it spreads completely. If there are particle residues, or if there are lumps or soaps remaining, it is unqualified. If it spreads completely or dissolves completely, it is qualified.

[0065] In the effect example, while maintaining the proportion of the ditaurate in each of Examples 1-5 unchanged, add water to prepare surfactant systems with a water content of 70% respectively.

[0066] The preparation method is as follows: Add the formulated amount of water and heat it to 50 °C with stirring to dissolve, to obtain the surfactant system.

[0067] Perform performance tests on the surfactant systems prepared above, and the results are as follows:

[0068] Surfactant system Example 1 Example 2 Example 3 Example 4 Example 5 Appearance (25 °C) Transparent liquid Transparent liquid Transparent liquid Transparent liquid Transparent liquid Appearance (10 °C) White paste Transparent liquid Transparent liquid White paste White paste Dissolution temperature / °C 23.5 3.8 3.0 10.9 13.6 Spreading property of 25 °C paste ○ ○ ○ ○ ○

[0069] Among them, ○ means qualified in the paste spreadability test at 25 °C.

[0070] Comparing with the results above and the Examples A1-9 in the patent application CN116098821A, it can be seen that the method provided by the present invention further reduces the dissolution temperature of the paste and improves the usability on the basis of the data in the patent application. Specifically:

[0071] In Examples 1-5 of the present invention, the ratios of disulfonates (N-acyl taurate and N-acyl methyl taurate) are 15:329, 166:172, 89:71, 152:35, and 12:153 in sequence.

[0072] However, the data pattern in Examples A1-9 of the patent application CN116098821A is that during the change of the disulfonate ratio from 9:1 to 1:9, the dissolution temperature of the paste first decreases and then increases, with the best at 1:1, which can dissolve at 5.3 °C, and the worst at 1:9 and 9:1, which dissolve at 33.3 °C and 19.1 °C respectively.

[0073] However, according to the Examples of the present invention, the disulfonate ratio in Example 1 is less than 1:9 and close to 1:22. Unexpectedly, the dissolution temperature of Example 1 prepared by the method provided by the present invention is as low as 23.5 °C, that is, even under the unfavorable disulfonate ratio, a significantly lower dissolution temperature is still obtained.

[0074] For Examples 2 and 3 in the present invention, a disulfonate ratio close to 1:1 is adopted, and their dissolution temperatures are further decreased to 3.8 °C and 3.0 °C compared with 5.3 °C. The dissolution temperatures in Examples 4 and 5 are also as low as 10.9 °C and 13.6 °C.

[0075] At the same time, the surfactant systems prepared in each example all show good paste spreadability at 25 °C. Thanks to the improvement of the preparation process and the better disulfonate ratio, Examples 2 and 3 can also maintain a liquid state at 10 °C.

[0076] In summary, the disulfonate prepared by the preparation method provided by the present invention can significantly reduce the dissolution temperature of the surfactant in the preparation of the surfactant system.

[0077] Effect Example 2 Experience test on the use of the disulfonates prepared in Examples 1-5 in the preparation of cleaning compositions

[0078] An experience test was carried out on the disulfonates prepared in Examples 1-5. The specific test method is as follows:

[0079] A total of 20 testers were recruited to evaluate the samples prepared in Examples 1-5 in sequence. The evaluation method was as follows: the samples were placed at 25°C and kept at a constant temperature for 48 hours, then 0.3 g of the sample was extruded onto the wet and clean hands, rubbed with the hands until the whole hand was covered, and then washed with water; the opinions of the testers on the use of the samples were collected in the form of an evaluation form, and the foaming property during the washing process and the tight feeling after washing were evaluated. The results are as follows:

[0080] Surfactant system Example 1 Example 2 Example 3 Example 4 Example 5 Foaming property ▲ ▲ ▲ ▲ ▲ Tightening feeling ● ● ● ● ●

[0081] The meanings of the symbols in the table are as follows:

[0082] ▲: More than 14 testers thought the foam was rich;

[0083] △: 10-13 testers thought the foam was rich;

[0084] ▽: 7-9 testers thought the foam was rich;

[0085] ▼: 3-6 testers thought the foam was rich;

[0086] ●: More than 14 testers thought there was no tight feeling after washing;

[0087] ○: 10-13 testers thought there was no tight feeling after washing;

[0088] □: 7-9 testers thought there was no tight feeling after washing;

[0089] ■: 3-6 testers thought there was no tight feeling after washing;

[0090] At the same time, for comparison, products of sodium N-lauroyl taurate (95%), sodium N-lauroyl methyl taurate (95%), sodium N-cocoyl methyl taurate (95%), and sodium N-cocoyl taurate (95%) produced by Zhangjiagang Greentech Chemical Co., Ltd. were selected, and reference samples with the same content of N-cocoyl / lauryl taurate and N-cocoyl / lauryl methyl taurate (abbreviated as N-acyl taurate and N-acyl methyl taurate) as those in Examples 1-5 were prepared according to the same procedure for testing. The results are as follows:

[0091]

[0092] It can be seen that compared with the reference samples obtained by mixing the products of Examples 1-5 prepared by the specific method with the commercially available products, the foaming property of the products of Examples 1-5 is significantly better, and at the same time, the tight feeling of Examples 1-5 is significantly better than that of the reference samples, which fully shows that the cleaning composition prepared by the specific method of the present invention has better foaming property and appropriate detergency.

[0093] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement made by those of ordinary skill in the art to the technical solution of the present invention shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A preparation method of a ditaurate, characterized in that, it comprises the following steps: (1) React 200 g of lauric acid, 300 g of sodium taurate, 1 g of sodium hydroxide, and 150 g of propylene glycol to obtain a reaction product containing N-acyl taurate; (2) Without separation and purification, directly react the reaction product obtained in step (1) with 45 g of dimethyl carbonate, and distill off the residual solvent to obtain a ditaurate of N-acyl taurate and N-acyl methyl taurate; The conditions of the reaction in step (1) are: temperature is 190 °C, time is 2 h; The conditions of the reaction in step (2) are: reflux reaction for 1 h.

2. A preparation method of a ditaurate, characterized in that, it comprises the following steps: (1) React 330 g of coconut oil, 80 g of sodium taurate, 1 g of calcium oxide, and 80 g of glycerol to obtain a reaction product containing N-acyl taurate; (2) Without separation and purification, directly react the reaction product obtained in step (1) with 20 g of dimethyl carbonate, and distill off the residual solvent to obtain a ditaurate of N-acyl taurate and N-acyl methyl taurate; The conditions of the reaction in step (1) are: temperature is 150 °C, time is 7 h; The conditions of the reaction in step (2) are: reflux reaction for 2 h.

3. The ditaurate prepared by the preparation method according to any one of claims 1-2.

4. Use of the ditaurate prepared by the preparation method according to any one of claims 1-2 in the preparation of a surfactant with high foaming performance.

Images