CS197793B1 - Method of producing dimethyl-alkyl-amine oxide - Google Patents

Description

The invention relates to a process for the preparation of dimethylalkylamine oxide.

Dimethylakylamine oxides have long been known foaming agents, intended not only for the formation but also for stabilization of bath foams, cosmetic shampoos, etc. , e.g., coconut oil, or is obtained chemically by oxidation of paraffin or by selective polymerization of low olefins. This alkyl can be characterized as a saturated or unsaturated hydrocarbon chain Οθ to C 1-6. Aqueous hydrogen peroxide at a concentration of 2.7 to 75% by weight is most commonly used to oxidize dimethylalkylamine to dimethylalkylamine oxide. HgOg, a less common and practically only laboratory scale oxidizing agent used are peracids, Caroic acid, sodium hypochlorite and the like. Let us denote this production method by the symbol A. A major disadvantage of process A is the intensive foaming of the reaction mixture during production, especially in large industrial volumes. The high foaming of the reaction mixture necessarily results in low reactor loading and long reaction times. (To illustrate, 700 kg of product are produced in 60 hours in a 1600 liter reactor). However, the oxidation of dimethylalkylamine to dimethylalkylamine oxide can also be carried out in an organic solvent environment such as ethanol, acetic acid, dioxane, acetone, and the like. All but the other are only laboratory, not industrial. The reaction process carried out in ethanol with an aqueous solution of hydrogen peroxide is described in German patent 664,425 (1938), patent DE 1163,850 (1964) and literature Jerchal D.

197 793

197 793

Jung G. Ber. 85 (1938). The process B is characterized in that the starting reaction mixture contains 8 to 17% fatty tertiary amine, 60 to 88% ethanol and 4 to 32% water and an aqueous solution is gradually added to the mixture. hydrogen peroxide concentration of 6 to 30%. In the case of process B, the oxidation carried out in an ethanol environment from an industrial point of view removes unbearable foaming during manufacture, but in this way a product of markedly deteriorated quality, expressed in its foaming capacity, is obtained. The product cannot be used for cosmetic purposes since it contains a considerable amount of acetic acid and by-products of the oxidation reaction. Another disadvantage of process B is the increased fire hazard associated with industrial production.

These disadvantages are overcome by the process according to the invention, which consists in using only the amount of ethanol or isopropanol which is necessary for the homogeneity of the heterogeneous fatty amine-water system at the start of the reaction. This amount is from 10 to 22% by weight, so that the starting reaction mixture contains 75 to 90% by weight, dimethylalkylamine, 10 to 22% by weight. % ethanol or isopropanol and up to 3 wt. water.

The process according to the invention makes it possible to achieve a high performance of the production equipment while maintaining the quality of the product in comparison with the known processes. The product produced by the process of the invention is fully suitable for use in all cosmetic foaming compositions.

Example 1

In a 1600 liters reactor at a temperature of about 20 DEG C., 300 kg of dimethyl cosamine (average molecular weight 230) and 60 kg of 96 wt. ethanol. The reaction mixture is heated to 68-75 ° C with stirring and 17.5 wt. hydrogen peroxide at 365 kg. The peroxide addition takes about 6 hours at 68-86 ° C. After the reaction, 370 kg of water were added. The product thus obtained had a foaming power (as measured by the Rosee-Milles method at a concentration of 1 g / l and a time of 1 min.) Of 93 ml, an analogous sample prepared by Method A 95 ml and Method B 74 ml. In comparison with process A (700 kg in 60 hours), 1,000 kg in 16 hours was produced.

Example 2

In a 1600 liters reactor at a temperature of about 20 ° C, 300 kg of dimethyl cosamine (average molecular weight 230) are mixed with 60 kg of isopropanol. The reaction mixture is heated to 68-75 ° C with stirring, and at the same temperature 365 kg of 17.5 wt. hydrogen peroxide. After the reaction, 370 kg of water were added. The product thus obtained had a foaming power (as measured by the RosseMilles method at a concentration of 1 g / l and a time of 1 min.) Of 87 ml, an analogous sample prepared by Procedure A 95 ml and Method B 68 ml. Also, compared to process A (700 kg in 60 hours), 1000 kg was produced in 16 hours.

Claims (1)

A process for the production of dimethylalkylamine oxide wherein the alkyl is a hydrocarbon chain of Οθ to (% θ saturated or unsaturated) by oxidation of dimethylakylamine, characterized in that aqueous hydrogen peroxide at a concentration of 10 to 22% by weight of H ₂ O ₂ is added to the mixture 90% by weight of dimethylakylamine, 10 to 22% by weight of ethanol or isopropanol and water in an amount of up to 3% by weight, at a temperature of 68 to 85 ° C.