DE2063421A1 - Surface-active imidazoline derivs - having high compatibility with skin - Google Patents

Abstract

Tertiary imidazolines of formula: (in which R1 is a satd. or unsatd., straight or branched chain 7-21C alkyl; and R2 represents -(CH2)n OH, where n= 2-4) are reacted with a halogenocarboxylic acid or a halogenosulphonic acid as a quaternising agent. The process is improved in that the imidazoline deriv. is heated to 40-60 degrees C (pref. 55 degrees C), and treated with the required amt. of the quaternising agent (pref. chloroacetic acid), and the pH of the reaction mixture is adjusted to 7-8 (pref. 7.5) by addition of an alkali. The products are suitable for use in body and hair treatment compsns.; they do not cause irritation.

Description

Process for the production of particularly skin-friendly imidazoline derived surfactants Imidazoline compounds derived from fats or fatty acids have achieved great practical importance in surfactant chemistry. Of the different Types that are used today are mainly characterized by the amphoteric ones their complete biodegradability, their good skin tolerance and their Miscibility with all other surfactants.

This last fact makes it possible to combine amphoteric imidazolines with nonionic, to use anion and cationic surfactants in the binary system.

Although the Imidazoline Amphotere available on the market many xxx are preferred to other surface-active products in hair and body care, because they show less irritation to the skin and especially the eyes a further reduction in the irritant effect represents a great step forward. It was therefore the aim of the applicant to create amphoteric imidazolines that previously known preparations are superior in this and also in other respects.

The main body of amphoteric imidazolines with surface-active properties is a long-chain imidazoline (Formula Ir in which R1 stands for a saturated or unsaturated, straight-chain or branched-chain alkyl radical with C7-C21, R2 and (aH2) nOH with n = 2-4.

The imidazoline derivatives can be prepared in a known manner from fatty acids or fatty esters and a primary / secondary diamine of the formula 2.

H H2 N-CH2- CH2 - N- R2 Like all tertiary bases, these bodies show a strong Aikai reaction and have a caustic and damaging effect on the skin. It must therefore be the goal of producing particularly skin-friendly preparations not only to react off all tertiary bases as much as possible through quartering, as well as the removal of other amines, some of which are still in the intermediate product from the starting material exist or, as should be shown, in compliance with the procedural rules, as detailed in U.S. Patents 2,528,378 and 2,773,068 will.

Experience has shown that the cyclization of the aminamide initially formed does not come to an end completely. There are therefore residues (approx. 3%) of a secondary amine in the reaction mixture.

The provisions of U.S. Patents 2,528,378 and 2,773 06d teach that the quaternization of the imidazolines is carried out in such a way that the tertiary amine with the quaternizing agent under strongly alkaline conditions in an aqueous medium at temperatures around 95 ° C can react. It is known (Törnquist, V Inter. Congress for surface-active substances Barcelona 1968, 1 ect A / III 16; G. Bara, Annual Neeting of the A.O.C. S New Orleans 1970) that imidazoline compounds as Easily hydrolyze amidine-like compounds and in this case a Hydroxyäthylaminoäthyifettsäureamid back down. This creates a secondary base that makes the quaternization reaction difficult is accessible.

This decomposition process naturally also causes the Gelialt the desired amphoteric imidazoline.

It is also known that e.g. chloroacetic acid or similar halogen carbon and sulfonic acids at elevated temperatures and in aqueous solution at high pH are subject to rapid hydrolysis, e.g. when using sodium hydroxide to form sodium glycolate and drive to the table salt. (1i.F. Behrenke a.

EC Britton, Ind. Eng. Chem. 38, 544, 1946.) It is also known that quarternic hydrogen reactions with haloarboxylic acids and halosulfonic acids proceed only very slowly and not quantitatively. It is therefore necessary to work with considerable excesses of halogen acids in order to achieve a tolerable tertiary amine content in the finished products. By using this large excess, however, hydroxy acid salts and metal halides accumulate in the finished products, which can cause great difficulties when formulating into ready-to-use cosmetics and therefore have to be removed separately by a cleaning process according to US Pat. No. 3,559,275 and others. The formula given in U.S. Patent 2,773,068 which is supposed to describe the compound which is supposed to result from the treatment of a fatty imidazoline derivative with 2 molecules of chloroacetic acid is absurd, since etherification requires the formation of an alkali alcoholate, which is not the case in an aqueous system. Accordingly, the products prepared according to the regulations have the same IR spectrum and the same OH number as the sample synthesized from 1 molecule of chloroacetic acid according to US Pat. minor. Dertiary amine content is different.

The procedure for carrying out the invention is known in the art in the synthesis of the cyclic tertiary amine and then quaternized by the halocarbon or halosulfonic acid salt of the base in aqueous solution and heated up to max. 500 a.

With stirring, alkali is now slowly added in such a way that the pH of the mixture is always kept around the neutral point.

The imidazoline ring is stabilized by the formation of the salt and the loss is due to hydrolysis of the halocarboxylic acid and halosulfonic acid, respectively reduced to the minimum by observing neutral conditions. Under these Conditions increases the yield of the desired amphoteric body up to 76 compared to 60 using U.S. Patent 2,528,378.

The ring system is largely retained, without significant amounts of open-chain products.

If the reaction is carried out with another under the same neutral conditions Molecule of chloroacetic acid carried on, one finds a tertiary amine content of about 7, while under the conditions of US Pat. No. 2,773,068, about 30 ffi can be found.

Chloroacetic acid pH 7.5 pH 13 1 mol $ 76% 60% 2 mol 93 ffi 70% 5 moles 97% 78% It is of course understandable that products of this type have a significant content of undesirable electrolytes.

To remove the harmful tertiary amine to the point of completion to drive, it is now clear that other and better ways must be followed, Ways that do not leave unwanted by-products, such as electrolytes, in the product. It has now been found, surprisingly, that in the presence of the condensation of one molecule of imidazoline base and one molecule of halocarboxylic acid or halosulfonic acid formed amphoteric the remainder of the remaining tertiary amine by oxidation can be removed smoothly with peroxides, preferably hydrogen peroxide. This creates the amine oxide of the tertiary imidazoline base. So far are surface-active Amine oxides produced only from the corresponding tertiary amines in aqueous solutions sometimes in the presence of small amounts of the acetic acid salt of the corresponding tertiary amine, which is said to have the function of an emulsifier. By being present of the amphoteric imidazoline already formed, the reaction of the remaining tertiary Amine smoothly in homogeneous, aqueous solution in front of you by adding a small excess deg oxidizing agent slowly added dropwise over the calculated temperature at 40-600C. A mixture of amphoteric imidazolines and amphoteric imidazolines is thus obtained in a smooth reaction Imidazoline oxides, the relative content of which can be varied within wide limits, depending on how far you are going to move forward with the quarter in the first step and how much tertiary amine is intended to remain in the mixture.

Surface-active amine oxides have recently been of great importance because it is known as a particularly skin-friendly detergent and body care product are. Numerous suggestions for the manufacture and use of this class of substances have since appeared in the literature.

Amine oxides with surfactant properties are also particularly suitable for Manufacture of mixtures with other detergents, because of their distinctive properties non-ionic character, no mixing limits are set. The invention enables it is therefore very easy to produce a random mixture of two types of surfactants, which together, as well as individually, with cationic or anionic surfactants, as can of course also be used with non-ionic binary systems.

It was already said at the beginning that in the manufacture of the tertiary Imidazoiinbasen from fatty raw materials and diamine small amounts of other amines in the Reaction mixture remain, although these impurities impair the usefulness of the Affect the end product little, they have a disruptive effect on the other chemical processes. When quartered, they consume because of, among other things their relatively low Molecular weight disproportionately high of the quaternizing agent and therefore also provide a further proportion of undesired D'electrolytes.

It has also been found that some of these impurities are slow or not convert into quaternary compounds at all. It is therefore according to the invention suggested all non-tertiary bases after careful preparation of the imidazoline remain in the reaction by adding the calculated amount of an acylating agent or the like to eliminate. This is especially important when there is an oxidation of the tertiary Amines after the quaternization is intended, as all non-tertiary amines though also react with peroxides, but do not deliver stable products. Secondary amines form unstable oxides which quickly become di-substituted. Rearrange hydroxylamines, which are then further oxidized to nitroso and nitro bodies and oximes. Some these derivatives are intensely colored and thereby change the appearance of the end product affect unfavorably.

The invention is explained below using a few examples: Example 1 94.5 kg of chloroacetic acid (1 kmol) are dissolved in 300 kg of water and in presented to a boiler with stirrer. The solution is with 268 kg of 1-hydroxyethyl-2-lauryl-imidazoline added (1 kmol). The mixture is mixed with so much caustic soda that Maintains a constant pH of 7.0-7.5 in the reaction mixture. One leaves at 550 Stir C; in between you ensure that by adding caustic soda that the The reaction mixture maintains a pH of 7.0 - 7.5.

After 24 hours, the rest of the caustic soda is added to the reaction mixture added; the total amount of caustic soda should be 40 kg (1 kmol).

Then stir until a constant Adjusts a pH value of 8.0 - 8.4.

(The pH measurements are made electrometrically in a 10% solution The analysis of the aqueous solution shows that 76% of the 4 used 1-Hydroxyäthyl-2-Lauryl-Imidazolins aich zuia Be tain have implemented. The reaction mixture is adjusted to a pH value of 5 - 6 by adding aqueous acid.

The mixture is mixed with 34 kg of hydrogen peroxide (30% strength aqueous solution 0.3 kmol) carefully added. The mixture is stirred at 500 ° C. until it is in the reaction mixture no hydrogen peroxide can be detected. Analysis of the final product results, that over 99% of the 1-hydroxyethyl-2-lauryl-imidazoline used becomes the ampholyte or N-oxide have implemented.

Example 2 196.5 kg of sodium 2-hydroxy-3-chloro-propahoulonst are used dissolved in 452 kg of water and placed in a kettle with a stirrer. The solution will be added 268 kg of 1-hydroxyethyl-2-lauryl-imidazoline (1 kmol). The mix will stained with so much caustic soda that there is a constant pH value in the reaction mixture 7.0 - 7.5 lasts. The mixture is allowed to stir at 550 ° C .; wiping through you take care of it by adding of caustic soda that a pH of 7.0-7.5 is maintained in the reaction mixture.

After 24 hours, add the rest of the caustic soda to the reaction mixture added; the total amount of soda ash should be 20 kg (0.5 kmol). Afterward Let n en continue to stir until alct sets a constant pH value of approx. 8.2.

(The pH measurements are carried out electronically in a 10% aqueous solution carried out.) An analysis of the aqueous solution shows that 80% of the used 1-Hydroxyethyl-2-lauryl-inidazolines have converted to the ampholyte.

The reaction mixture is adjusted to pH by adding acetic acid set from 5 - 6. The mixture is with 28 kg of hydrogen peroxide (30% aqueous Solution, 0.25 kmol) carefully added. The mixture is stirred at 500 C until the No hydrogen peroxide can be detected in the reaction mixture.

An analysis of the end product shows that over 99% of the used Have converted 1-hydroxyethyl-2-lauryl-imidazoline to the ampholyte or N oxide.

Example 3 66.1 kg of chloroacetic acid (0.7 kmol) are dissolved in 300 kg of water dissolved and placed in a kettle with a stirrer. The solution is mixed with 268 kg of 1 1-hydroxyethyl-2-lauryl-inidazoline (1 kmol) added. The mixture is stirred at 550 ° C. for 15 hours. Then it is heated to 900 e and stir for another two hours.

An analysis of the aqueous solution shows that it is 67% of the amount used Have implemented 1-hydroxyethyl-2-lauryl-imidazoline to betaine.

The reaction mixture is adjusted to pH by adding acetic acid set from 5 - 6. The mixture is mixed with 45.4 kg of hydrogen peroxide (30 goat Solution, 0.4 kmol) carefully added. The mixture is stirred at 550 C until the No more hydrogen peroxide can be detected in the reaction mixture. An analysis of the The end product shows that there is over 99 ffi of the 1-hydroxyethyl-2-lauryl-imidazoline used have converted to hmpholyt or N-oxide.

Claims (4)

P a t e n t a n. S p r ü c h e 1. Process for the production of particularly skin-friendly surfactants derived from imidazoline by converting tertiary imidazoline of the structure in which R1 is a saturated or unsaturated, straight-chain or branched-chain alkyl radical with C7 -R2 for - (CH2) nOII with n = 2-4, with halocarboxylic acids or halosulfonic acids as quaternizing agents, characterized in that the imidazoline is at a temperature between 40 and 600 ° C., preferably 55 ° C., with the amount of quaternizing agent, preferably chloroacetic acid, required for the desired reaction, and the reaction mixture is kept at a pH between 7 and 8, preferably at pH 7.5, by adding lye, if necessary . 2. Verabren according to claim 1, characterized in that the reaction mixture after completion of the quaternization reaction to implement the remaining residual content is oxidized on imidazoline. 3. The method according to claim 2, characterized in that the oxidation calculated by adding an imidazoli compound that is not quaternized to the tightness Amount of hydrogen perox @ d at a temperature z @ ischen 40 and 60 ° C takes place. 4. Procedure according to one of the @@ Proverbs 1 to 3, d u r c h g e k It is noted that the @@ renaturation stage - if necessary - an acy @@ eration stage is connected upstream.