DE1010970B - Process for the preparation of N-acyltaurine salts - Google Patents

Description

Process for the preparation of N-acyltaurine salts The invention relates to Improvements in the manufacture of anionic surfactants, on nitrogen taurine salts bearing higher molecular weight acyl groups.

Sales of higher molecular weight fatty acids, fatty acid chlorides and Fatty acid esters with 2-amino-alkanesulfonic acids (taurines) and their alkali salts for the production of anionic surfactants, which are used as wetting agents, Detergents, softeners and dispersants can be used can is known. In the German patent specification 655 999 there are several methods described for the production of such surfactants, but the only one Process that has hitherto been used technically is that according to which an acid chloride in an aqueous medium with a 2-aminoalkanesulfonic acid in the presence an acid neutralizing agent such as sodium hydroxide or sodium carbonate will. The preparation of the acid chloride used as an intermediate is, however Not only dangerous, but also time consuming and costly as it is on the one hand the use of phosphorus trichloride and, on the other hand, at least one more requires additional work stage. In addition, if the acid chloride with a Taurine or a taurine salt is converted into an anionic surfactant Containing a substantial amount of salt, for example sodium chloride, which, however, is very undesirable when using said surfactant is used in detergents or soaps. The presence of the Sodium chloride in such approaches they also become excessively strongly hygroscopic, moreover, its removal is very costly. Example 14 of the cited patent describes the reaction of about 1 mole of palmitic acid with about 2 moles of N-methyl-taurine in an excess of tributylamine as a solvent. The yield of the desired However, N-acyltaurine salt is relatively small and there is a tendency for the formation of decomposition products and malodorous and discolored by-products, in addition, the tributylamine, e.g. B. by salting out can be removed.

In order to remedy these disadvantages, it is necessary to produce a salt-free one Product has already been proposed (P. B. Report 70344, T. H. K. Scientific Exchange Maximum No. 154 Register No. Ho 43/4), about 1 mole of a free fatty acid to condense with 1 mole of a taurine salt, but this did not become another Advantage achieved over the acid chloride process. Rather, it turned out that one Significant decomposition of taurine occurred, ammonia or methylamine were split off from which taurine was inevitable and the yield and quality of the products did not meet expectations in terms of smell and color.

The invention relates to a new and improved method for Production of taurine salts, which are attached to nitrogen by means of higher molecular acyl groups are occupied and contain no inorganic salts.

The invention consists in that, preferably in the absence of a solvent, at least 1.2 mol of an aliphatic or alicyclic carboxylic acid having at least 8 carbon atoms with 1 mol of a taurine salt of the general formula in which R1 is hydrogen or a hydrocarbon radical with 1 to 20 carbon atoms, R is hydrogen or a low molecular weight alkyl radical and M is alkali metal, alkaline earth metal or a tertiary or sterically hindered amine, heated in a neutral atmosphere to a temperature of about 200 to 320 ° and that during water formed in the reaction is removed.

The reaction that takes place can be illustrated by the following equation, in which stearic acid is used as the acylating agent and the sodium salt of N-methyltaurine is used as the taurine salt The process according to the invention eliminates the need to first prepare the fatty acid chloride as a precursor for its subsequent reaction with the taurine, and salt-free products are obtained. It has been found that this process also requires much shorter reaction times and excellent yields of a product in the form of a solid, rather than a slurry or a thin solution, are obtained. The product thus obtained is also excellent in purity and has no discoloration or bad odor. Although the exact reason for the improved results is not known, it can be assumed that the excess of free carboxylic acid in the reaction mixture stabilizes the taurine salt, thereby reducing its decomposition, increasing yields and reducing the formation of malodorous or discolored by-products will. In most cases, too, the use of an excess of the carboxylic acid used as acylating agent brings about a very desirable reduction in the viscosity of the reaction mixture.

Since an excess of carboxylic acid is used, the final product contains free carboxylic acid, if desired, by conventional extraction or distillation processes with overheated. Steam can be removed. According to the invention, however, such Product also with an inorganic or organic base, such as alkali metals, or treated with amines, such as triethanolamine, creating a soap of the carboxylic acid is created in the mass. The resulting mixture of soap and the nitrogen tauride substituted by higher acyl radicals can either immediately or after Addition of other substances in the manufacture of detergents in liquid or solid form can be used. The use of such preparations for the manufacture of solid detergents in powder or stick form is very beneficial. These preparations can also be used in the manufacture of skin creams, lotions, ointments, in food and feed, as foaming agent and for other purposes find in which the presence of a mineral acid salt of an alkali metal, Alkaline earth metal or ammonia or an amine is undesirable.

At higher temperatures, many of the taurine salts tend to decompose, while at temperatures that are too low, such as below 180 °, the reaction proceeds too slowly. The temperature to be used in each particular case therefore depends on the in each case used acid and in particular its molecular weight, the degree of Unsaturation and responsiveness. So can with acylation with lauric acid Lower temperatures are used than when acylating with stearic acid. While working temperatures of 200 to 320 ° as the extreme limits in general can be viewed, but will be in the range of 200 to 260 ° in most Cases get good results. Temperatures within this range result from 220 to 240 ° the best results if the usual reactants are used will. The reaction is at temperatures within the above ranges usually completed in about 10 hours, although that required to complete the reaction required duration in any special case also about 1/2 to 15 hours can be.

To prevent excessive discoloration of the product, in particular when using oleic acid and other acids that contain unsaturated components, it is necessary to prevent air from entering the reaction mixture. to exclude. For this reason, a neutral atmosphere, such as Nitrogen or a vacuum, can be maintained over the mixture. Are diminished If pressures are applied, absolute pressures of 10 to 200 mm Ilg column are preferred. Column pressures below 10 mm Hg can also be applied when the acid is not is too volatile. The level of vacuum is therefore dependent on the volatility of the acid and the reaction temperature dependent. Will the neutral atmosphere by using an inert gas such as nitrogen is maintained, the gas becomes preferable continuously passed over the reaction mixture, whereby the removal of the during the reaction formed water is favored.

Under certain conditions, the reaction can also take place in suitable high-boiling conditions Solvents such as chlorobenzene, dichlorobenzene, nitrobenzene, chlorinated paraffins, Tetrachlorethylene, trichloroethane, ethylene dichloride, propylene dichloride, toluene, xylene, Alkylbenzenes, alkylnaphthalenes. The use of such However, solvent generally has the disadvantage of higher cost, namely due to the cost of the solvent itself and the cost of recovery of the solvent and the replacement of losses. It also will in many cases the rate of reaction due to the insolubility of most sulfonic acid salts adversely affected in these solvents.

It has been found that in general amounts of about 1.5 to 2 Moles of acid per mole of taurine salt are sufficient. If necessary, however, the reaction mixture also a larger excess of the acid up to 6 to 10 moles or more per mole of taurine salt included if a product with a higher content of free carboxylic acid is desired should. By treating such a product with sodium or potassium hydroxide or an organic base to convert the free carboxylic acid into a soap a detergent mixture would then be obtained, the soap and nitrogen Contains higher acyheric taurine in any desired ratio. By an increase of the excess of the carboxylic acid used in the reaction mixture, however, although to a certain extent it supports the stabilization of the taurine salt is, at the same time also the cost of the product due to the higher heat consumption and increased carboxylic acid losses.

As carboxylic acids having at least 8 carbon atoms, according to the invention can be used, those of the aliphatic or alicyclic are preferred Belong to the series, although aromatic acids can also be used. Particularly the higher fatty acids are preferred. As higher aliphatic and alicyclic Examples of carboxylic acids are: caprylic acid, pelargonic acid, capric acid, Lauric acid, myristic acid, palinitic acid, stearic acid, oleic acid, ricinoleic acid, Linseed oleic acid, undecylic acid, tall oil acid, as well as acid mixtures consisting of different natural vegetable and animal oils such as olives, tallow, Castor, peanut, coconut, soybeans, cottonseed, Ucahuba, linseed, cod, Herring, bunker, cattle claws, sperm whale, palm trees, wheat, butter, babassu, kapok, hemp, Mustard, rubber seeds, rapeseed, saffron, sesame, or acids from the oxidation fractions from petroleum or from oxoaldehydes, naphthenic acids, abietic acids and the hydrogenated Derivatives of these acids and mixtures of acids. Other acids that are also possible are alkylbenzoic acids such as dodecylbenzoic acid, nonylbenzoic acid, octylbenzoic acid, Alkyl naphthoic acid such as nonyl naphthoic acid.

In the above for the thawing salts which can be used according to the invention given formula, R can be hydrogen, Methyl, ethyl, isopropyl, R1 is hydrogen or a hydrocarbon radical of 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, butyl, heptyl, isooctyl, dodecyl, pentadecyl, stearyl, Abietinyl, oleyl, cyclohexyl, phenyl and M is an alkali metal such as sodium, potassium or lithium, an alkaline earth metal such as calcium, magnesium, barium, or a tertiary or sterically hindered amine, such as dicyclohexylamine, tributylamine, trioctylamine, Triethanolamine, N, N-diphenylmethylamine, N, N-dimethyloctadecylamine, tetraoxyethylethylenediamine mean. For example, the following 2-aminoalkanesulfonic acids can be in the form their salts are used: taurine, ditaurine, N-methyltaurine, N-methylditaurine, N-ethyl taurine, N-propyl taurine, N-isopropyl taurine, N-butyl taurine, N-isobutyl taurine, N-tert-butyl taurine, N-amyl taurine, N-hexyl taurine, N-cyclohexyl taurine, N-phenyl taurine, N-methyl-2-methyltaurine, N-methyl-2-ethyltaurine, N-methyl-1, 2-dimethyltaurine, N-octyltaurine, N-dodecyl taurine, N-stearyl taurine.

The taurine salts are preferably in the form of their dried powders or used as aqueous solutions, since the water is removed during the reaction will. Except that the viscosity of the reaction mixture is lowered in many cases As noted above, the carboxylic acid also assists in stabilization the taurine salts. Because when taurine in the absence of carboxylic acids to high temperatures are heated, amines or ammonia are easily split off and ditaurines or Tritaurine formed.

Taking into account the high yields obtained by the process according to the invention, in addition to the main reaction of the carboxylic acid with the taurine salt, the following reactions apparently also occur with ditaurine salt: Ditaurine impurity in taurine Similarly, tritaurine could react to form one molecule of amide, two molecules of ester, and one molecule of water.

The products obtained by the present process are valuable anionic surfactants that can be used in many ways. the most salient feature of these products lies in their great activity Surfaces and interfaces that are used in many technical fields enables. For example, they can be used as a wetting agent, foam or detergent the treatment and processing of textiles; for converting liquid or solid substances that are insoluble in water, such as hydrocarbons, higher Alcohols, oils, fats, waxes and resins, in creamy emulsions, clear solutions or fine stable dispersions; for carbonization; when dyeing; for pasting Dyes; in fulling, gluing, impregnating and bleaching; as a cleaning agent in hard water; in pickling and tanning processes; when dyeing acetate with insoluble Dyes; for the production of dyes in finely divided form; for dispersible Dye powder; for the production of foam for fire extinguishers; as a means of improvement the absorption capacity of fibrous materials and as an aid in soaking be used by hides and skins.

The products can also be used as emulsifiers in emulsion polymerization, as mercerising agents, wetting agents, dispersing agents, cleaning agents, Penetrants, softeners, lime soap dispersants, dishwashing detergents, antistatic agents, disinfectants, insecticides, moth repellants, bactericides, Fungicide and Biocide can be used. They can also be used as a means of protection against fogging on glass or other surfaces where the accumulation of an aqueous mist or veil is disadvantageous. Finally you can use the Silk industry as additives to the spray mass or to the spinning bath and as an aid serve in clarifying the viscose. Finally, they can also be used in hydraulic fluids Find use to improve viscosity properties. Particularly useful the products are also used to break petroleum emulsions.

They can also be used as an anti-corrosive agent, such as rust inhibitor, in the protection of metals, especially ferrous metals; in acid pickling baths; in acidic Cleaning preparations and in baths for electrical plating.

As mentioned, the products can also be used in the manufacture of skin creams, Lotions, ointments and other cosmetic preparations, such as hair wave products, shaving cream, Shampoo, toothpaste, etc. can be used. They can also be found in food as foaming agents, emulsifying agents and plasticizers.

In the following examples, parts are parts by weight if nothing other is indicated.

Example 1 In a three-necked flask with a volume of 250 ccm, which is equipped with a mechanical stirring device, a stopper and a connecting pipe for a vacuum suction device was provided, 11.8 g of dry sodium salt of N-methyl-taurine (85 () / o purity, 0.062 mol) and 35.2 g of stearic acid (0.124 mol). The flask was then in a thermostatically held at 220 ° oil bath used and in this 10 hours held under the reduced pressure of a suction device (approximately 15 to 22 mm Hg column), the mixture being stirred through.

The product melted at 220 ° was cooled and the product obtained brittle, waxy, yellowish mass removed from the flask. This product had the smell of stearic acid but not the unpleasant odor of an amine.

The weight was 45.5 g. The product contained 540/0 sodium salt of N-stearoyl-N-methyl-taurine, which corresponds to a yield of 93%, calculated on N-methyl-taurine, is equivalent to.

The product was an excellent detergent for cotton, when it is with sodium tripolyphosphate, soda ash and the reaction product of the Example 8 below. This mixture was too effective in hard water, in which case it does not produce lime soap deposits became.

Analysis of the product N-stearoyl-N-methyltaurine, sodium salt 54 0/0 (1) stearic acid ........................ 36.2 ° / 0 (2) N-methyltaurine, sodium salt ......... 1.50 / 0 (3) Neutral extractables. . . . . . . . . 3.00 /, (4) Other substances (by difference) ....... 5.30 / 0 (5) (1) Analysis according to the method described in Nature, 160, p. 759 (1947), and Trans. Faraday Soc., 44, pp. 226-239 (1948), described methylene blue methods. (2) By extraction with petroleum ether and titration of the petroleum ether residue.

(3) By titrating the solution with petroleum ether for removal the fatty acid had been extracted.

(4) From the weight of the petroleum ether residue, reduced by the Stearic acid (2). Can contain stearic anhydride and high molecular weight ketones and the like included.

(5) Includes moisture and impurities found in technical grade N-methyl-taurine are included.

The results of tests carried out in the same way as in Example 1 are given in the following table. Molar ratio tempe yield, Taurine used by acylating agent from acylating time is calculated game on taurine to taurine ° C hours o / ' 2 stearic acid N-methyltaurine, Na salt 1.5: 1 220 10 90 3 same as 1: 1 220 10 62 4 same as 2: 1 240 10 92.5 5 same as 2: 1 180 10 35 6 same as 2: 1 260 2 87 7 lauric acid like 3: 1 200 10 91.75 8 same as 2: 1 200 10 90 9 Oleic acid taurine, Na salt 2: 1 220 10 91 10 as well as 6: 1 220 10 92.6 11 Palmitic acid N-methyltaurine, Na salt 2: 1 220 10 90 12 stearic acid n-butyltaurine, sodium salt 2: 1 220 10 90 13 Oleic acid, Na salt N-methyltaurine, Na salt 1: 1 220 10 2.8 14 same as 2: 1 220 10 8 15 stearic acid 0.5 mol of NaOH per 2 mol of acid, the same 2: 1 220 10 92.8 (1.5 free Acid: 1) 16 stearic acid 1.5 moles of NaOH per 2 moles of acid, the same 2: 1 220 10 61.3 (0.5 free Acid: 1) 17 stearic acid taurine, inner salt 1.5: 1 220 10 10 18 tall oil N-methyltaurine, sodium salt 2: 1 220 10 73 19 Distilled tall oil like 2: 1 220 10 87 20 naphthenic acid fraction (mol- weight = 330 to 350) the same 2: 1 220 10 81 21 stearic acid like 2: 1 220 10 94 In Example 6, the reaction was carried out at atmospheric pressure under nitrogen which was passed through the flask in a slow stream while heating.

Examples 3, 13 and 16 have been included in the table, the importance of using an excess of carboxylic acid in the present invention Process to illustrate. The example s has been added to emphasize the importance of working in the temperature range given above. the Examples 13, 14 and 16 also illustrate the importance of using the Acylating agent in the form of the free carboxylic acid in excess of the amount of the taurine salt instead of in the form of its sodium salt. Examples 15 and 16 illustrate that the sodium salt of the fatty acid does not interfere with the conversion as long as the necessary Excess free carboxylic acid is maintained in the reaction mixture. That Example 17 has been included in the table to highlight the importance of use of taurine in the form of its salt instead of in the form of the free sulfonic acid to illustrate internal salt formation. Example 2 Using the in the example described device were 92 g (0.324 mol) oleic acid with 30 g (0.162 mol) 870/0 N-methyl-taurine (sodium salt) mixed. The mixture was stirred and in one Oil bath heated to 220 ° for 4 hours. During the first part of the heating was owing moderate foaming can be observed with the development of water. The cloudy slurry gradually turned into a clear yellow melt. The melt was on Cooled 95 ° and the excess oleic acid neutralized by a solution of 6.5 g (0.162 moles) of sodium hydroxide in a small amount of water was added. The pH value was increased by adding a small further amount of sodium hydroxide 9 brought. The paste then turned to a light yellow solid in a vacuum oven Product dried weighing 113 g. This product contained 43% N-oleyl-N-methyltaurine sodium salt, the remainder consisted mainly of sodium oleate.

The product was then passed through a kneader five times and in Soap shape into a small soap bar processes which the Containing taurine compound. This product had good foaming and cleaning properties, even if it was used in hard water.

Claims (4)

PATENT CLAIMS: 1. A process for the preparation of N-acyl-taurine salts by heating higher molecular weight carboxylic acids with taurine salts, characterized in that at least 1.2 mol of an aliphatic or alicyclic carboxylic acid with at least 8 carbon atoms with 1 mol of taurine salt of the general formula in which RI is hydrogen or hydrocarbon radicals with 1 to 20 carbon atoms, R is hydrogen or a low molecular weight alkyl radical and M is an alkali or alkaline earth metal or a tertiary or sterically hindered amine, heated in an inert atmosphere to about 200 to 320 ° and the formed during the reaction Water removed. 2. The method according to claim 1, characterized in that there is used as acylating agent a higher fatty acid, preferably stearic acid, phenitic acid, oleic acid, lauric acid or tallow acids are used. 3. The method according to claim 1 and 2, characterized in that that the sodium salt of taurine or N-methyl-taurine is used as the taurine salt. 4. The method according to claim 1 to 3, characterized in that there is excess Acylating agent neutralized in the reaction product, preferably with sodium or Potassium hydroxide.