KR19980051819A - Process for preparing N-acyl-N-alkyl polyhydroxy fatty acid amide - Google Patents

Abstract

The present invention relates to an improved process for the preparation of N-acyl-N-alkyl polyhydroxy fatty acid amides which are natural nonionic surfactants. More specifically, the present invention reacts an N-alkyl polyhydroxy amine with a fatty acid alkyl ester in the presence of an alkali catalyst and, after completion of the reaction, adds ω-haloalkanoate in a dilution step to give an unreacted N-alkyl polyhydroxy. By treating the amines and removing the fatty acid alkyl esters by hydrolysis with the catalyst used, N-acyl-N-alkyl polyhydroxy fatty acid amides with significantly reduced content of residual N-alkyl polyhydroxy amines and fatty acid alkyl esters are prepared. It is about how to.

Description

Process for preparing N-acyl-N-alkyl polyhydroxy fatty acid amide

The present invention relates to a process for the preparation of N-acyl-N-alkyl polyhydroxy fatty acid amides which are natural nonionic surfactants.

More specifically, the present invention reacts an N-alkyl polyhydroxy amine with a fatty acid alkyl ester in the presence of an alkali catalyst and then removes unreacted N-alkyl polyhydroxy amine with ω-haloalkanoate to remove the odor of the amine. And unreacted fatty acid alkyl esters are hydrolyzed with an alkali catalyst used as catalyst to produce a high quality N-acyl-N-alkyl polyhydroxy fatty acid amide which is odorless and almost unreacted.

In general, since conventional surfactants pollute the environment and exhibit high irritation to the human body, there is a limit of petroleum-based resources as demand increases, and interest in natural-based surfactants is greatly increased due to the growth of natural oil and fat industry. It's happening. Therefore, in the field of surfactants, much effort is invested in the development of surfactants that are biodegradable, have very low irritation to the environment and the human body, and have excellent performance. Especially, surfactants using glucose, which are present in nature, and alkyl polyglucose Seeds and N-acyl-N-alkyl polyhydroxy fatty acid amides are receiving great attention as next generation nonionic surfactants. The present invention relates to the preparation of N-acyl-N-alkyl polyhydroxy fatty acid amides that are drawing attention as such next generation surfactants.

This natural N-acyl-N-alkyl polyhydroxy fatty acid amide is biodegradable as a nonionic surfactant, and has a higher foaming power and detergency than other nonionic surfactants. It can be used as a substitute for conventional surfactants in products with much contact with soaps, systemic detergents, baby products, shampoos, kitchen products, powder detergents and cosmetics.

N-acyl-N-alkyl polyhydroxy fatty acid amides are generally prepared by an amidation reaction in which N-alkyl polyhydroxy amines are reacted with fatty acid alkyl esters to obtain N-acyl-N-alkyl polyhydroxy fatty acid amides. With regard to, N-acyl-N-alkyl polyhydroxy fatty acid amides, a number of patents describe their use. For example, US Pat. No. 2,965,576 (1960) describes detergent compositions using N-acyl-N-alkyl polyhydroxy fatty acid amides, and US Pat. No. 3,654,166 (1972) uses softeners in detergent compositions. US Patent No. 4,021,539 (1977) describes cosmetic compositions comprising up to 25% by weight of N-acyl-N-alkyl polyhydroxy fatty acid amides as skin care or skin protectants.

Recently, there have been a number of patents relating to the preparation of N-acyl-N-alkyl polyhydroxy fatty acid amides, for example WO 92-06070 and U.S. Patents 5,338,487 (1994) and U.S. Patent 5,338,486 (1994). Describes a method of using an alkali catalyst in the reaction of N-alkyl polyhydroxy amines with fatty acid alkyl esters, an amidation reaction, in the preparation of N-acyl-N-alkyl polyhydroxy fatty acid amides. Alkaline catalysts used in this method are trilithium phosphate, trisodium phosphate, tripotassium phosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, pentasodium tripolyphosphate, pentapotassiumtripolyphosphate, lithium hydroxide, sodium hydroxide, potassium Hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, disodium tartrate, dipotassium tartrate, sodium potassium tartrate, trisodium citrate, tripotassium citrate, basic sodium silicate, basic potassium silicate Basic sodium aluminosilicate, basic potassium aluminosilicate and the like. However, this method uses an alkali catalyst and a solvent having a hydroxy group, for example, a solvent such as methanol, ethanol, propanol, isopropanol, 2,3-dipropanol, propylene glycol, etc., thus removing the solvent after the reaction is completed. There is a disadvantage that this is necessary.

U.S. Pat.Nos. 5,380,891 (1995) and WO 92-06071 and WO 92-06072 also use N-alkyl polyhydroxys using phase transfer catalysts such as fatty alcohol polyethoxylates, alkyl polyglycosides and lucamides, and the like. A method for producing N-acyl-N-alkyl polyhydroxy fatty acid amides in high yield by reacting amines with fatty acid alkyl esters is described. However, also in this method, since the reaction is carried out using a solvent having a hydroxyl group, the removal of the solvent is inevitable after the reaction is completed, and the treatment of the residual alkyl polyhydroxy amine is required.

As a method for the treatment of such residual alkyl polyhydroxy amines, Connor et al. In WO 94-06754 proposed a method for treating residual alkyl polyhydroxy amines with acetic anhydride. This method can effectively treat unreacted N-alkyl polyhydroxy amines, but has the disadvantage of producing an acetate equivalent to the equivalent ratio of acetic anhydride used after the reaction and having a strong smell of acetic acid.

In addition, a method of preparing N-acyl-N-alkyl polyhydroxy fatty acid amides by directly reacting N-alkyl polyhydroxy amines with fatty acid alkyl esters in the absence of a solvent in the presence of alkali catalysts has been described in a number of US patents and international patents. have.

As described above, various prior art methods for preparing N-acyl-N-alkyl polyhydroxy fatty acid amides have been proposed, but the N-acyl-N-alkyl polyhydroxy fatty acid amides prepared by such prior art methods are the color of the product. N-acyl due to solubility problems due to the residual of fatty acid alkyl esters and N-alkyl polyhydroxy amines used as reactants in the product as well as odors due to the residual of fatty acid alkyl esters and N-alkyl polyhydroxy amines in the product. There is a disadvantage that it is difficult to use in the product by reducing the excellent interfacial properties and environmental friendliness of the -N-alkyl polyhydroxy fatty acid amide.

Therefore, the present inventors conducted intensive research to find a means for solving the problems caused by the residual of fatty acid alkyl esters and N-alkyl polyhydroxy amines in preparing N-acyl-N-alkyl polyhydroxy fatty acid amides. As a result, after reacting the N-alkyl polyhydroxy amine with the fatty acid alkyl ester under an alkali catalyst, the unreacted N-alkyl polyhydroxy amine is treated by adding ω-haloalkanoate and the unreacted fatty acid alkyl ester is The present invention has been completed by discovering that high-quality N-acyl-N-alkyl polyhydroxy fatty acid amides free of odor and no unreactant can be prepared by hydrolysis with an alkali catalyst used as a catalyst.

Therefore, the present invention is to react the fatty acid alkyl ester and the N-alkyl polyhydroxy amine in the presence of an alkali catalyst, and then treat the remaining unreacted N-alkyl polyhydroxy amine by adding ω-haloalkanoate in the dilution step. The remaining unreacted fatty acid alkyl esters are hydrolyzed by the alkali catalyst used in the reaction to be converted to alkanoate (soap), resulting in extremely low content of residual fatty acid alkyl esters and N-alkyl polyhydroxy amines and A process for producing a good quality N-acyl-N-alkyl polyhydroxy fatty acid amide with a color of Gardner 1 or less.

The N-acyl-N-alkyl polyhydroxy fatty acid amides prepared according to the process of the invention as described above are preferably compounds represented by the following general formula (1):

In the above formula,

R represents straight or branched chain alkyl or alkenyl having 7 to 17 carbon atoms,

R 'represents alkyl or hydroxyalkyl having 1 to 4 carbon atoms,

Z represents straight chain polyhydroxy alkyl having 3 or more hydroxy groups.

Hereinafter, a method for preparing N-acyl-N-alkyl polyhydroxy fatty acid amide according to the present invention will be described in detail.

First, an alkali catalyst, a fatty acid alkyl ester, and an N-alkyl polyhydroxy amine are put into a reactor and heated to perform an amidation reaction. At this time, methanol generated during the reaction is continuously removed.

After the reaction is completed, an aqueous solution of ω-haloalkanoate is added to the reaction mixture to treat the remaining N-alkyl polyhydroxy amine, and at the same time, the remaining fatty acid alkyl ester is hydrolyzed by an alkali catalyst used in the reaction. By conversion to soap, N-acyl-N-alkyl polyhydroxy fatty acid amides having a very low content of N-alkyl polyhydroxy amines and fatty acid alkyl esters are in the proportion of 30 to 60% by weight of the total weight of the reaction mixture. Manufacture.

Fatty acid alkyl esters in the process of the invention are preferably used higher fatty acid alkyl esters having straight or branched chain alkyl groups having from 7 to 17 carbon atoms, specific examples of which are methyloctanoate, methyldecanoate, methyldodecano 8, methyltetradecanoate, methylhexadecanoate or methyloctadecanoate or mixtures thereof.

The N-alkyl polyhydroxy amines used as another reactant in the process of the invention are preferably alkyl or hydroxy alkyl groups having 1 to 4 carbon atoms and straight chain polyhydroxy alkyl groups comprising at least 3 hydroxy groups N-alkyl polyhydroxy amines having, for example, N-methyl, ethyl, propyl or butyl glucamine or N-methyl, ethyl, propyl or butyl maltamine or mixtures thereof can be used. In this reaction, N-alkyl polyhydroxy amine is suitably used in the ratio of 0.8-1.3 equivalents, preferably 0.9-1.1 equivalents to 1 equivalent of fatty acid alkyl ester. When the N-alkyl polyhydroxy amine is used in a ratio of 0.8 equivalent or less, the residual amount of fatty acid alkyl ester becomes too large, and when it is used in a ratio of 1.3 equivalent or more, the residual amount of N-alkyl polyhydroxy amine is too large, which is not preferable. .

Alkali catalysts in this reaction are preferably sodium carbonate, potassium carbonate, sodium methoxide, potassium methoxide, sodium hydroxide and the like. The amount of the alkali catalyst is preferably 0.1 to 5% by weight, preferably 0.5 to 2% by weight of the total weight of the reaction mixture. If the amount is less than 0.1% yield is not good because the reaction rate is slow, even if more than 5% yield is not economical because it does not increase any more.

The amidation reaction according to the present invention can be carried out by both a direct method using no solvent and a solvent method using a solvent. When the reaction is carried out by a solvent method using a solvent, methanol is preferably used as the solvent. The amount of solvent is suitably 5 to 80% by weight, preferably 20 to 60% by weight of the total weight of the reaction mixture. In the case of the solvent method, the reaction temperature is a temperature for refluxing methanol, that is, 65 to 80 ° C. In the case of the direct method without using a solvent, the melting temperature of the N-alkyl polyhydroxy amine generally used is, for example, 80 to 80 ° C. 160 degreeC, Preferably it is suitable to be 130-150 degreeC. The reaction time generally takes 1 to 5 hours.

After carrying out the amidation reaction, upon completion of the reaction, ω-haloalkanoate is added to the reaction mixture to treat the remaining unreacted N-alkyl polyhydroxy amine, and at the same time, the remaining unreacted fatty acid alkyl esters It is converted to alkanoate (soap) by hydrolysis by the alkali catalyst used in the reaction without adding acid. This makes it possible to prepare N-acyl-N-alkyl polyhydroxy fatty acid amides with little residual unreacted fatty acid alkyl esters and N-alkyl polyhydroxy amines in the reaction mixture.

Examples of ω-haloalkanoates that can be used for the above purposes are preferably sodium 2-chloroacetate, sodium 3-chloropropionate, potassium 2-chloroacetate, potassium 3-chloropropionate, and the like. Included. ω-haloalkanoate is used in an amount of 0.01 to 0.05 equivalents to 1 equivalent of N-alkyl polyhydroxy amine when the fatty acid alkyl ester is used in an amidation reaction, and the excess of N-alkyl polyhydroxy amine is used. When used, it is used in ratio of 0.05-0.1 equivalent with respect to 1 equivalent of N-alkyl polyhydroxy amine.

According to the method of the present invention as described above, since there is little residual amount of unreacted N-alkyl polyhydroxy amine and fatty acid alkyl ester, there is no odor resulting therefrom, and the desired N-acyl-N-alkyl polyhydroxy There is no influence on the physical properties of the fatty acid amide as a surfactant so that a high quality natural N-acyl-N-alkyl polyhydroxy fatty acid amide surfactant can be obtained.

The present invention will be described in more detail based on the following examples, but these examples are only to aid the understanding of the present invention, and the scope of the present invention is not limited thereto by any means.

Example 1

In a four-necked flask equipped with a mechanical stirrer, a thermometer, and a condenser, 195 g of N-methylglucamine and 214 g of methyl dodecanoate were added thereto. . As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. At this time, the condenser was removed and a distillation apparatus was installed to continuously remove methanol and heated to 130-140 ° C. If methanol is not generated, the reaction is considered to be terminated, and the reaction mixture is diluted with 500 g of 1% by weight aqueous sodium 2-chloroacetate (ClCH ₂ COONa) solution to form N-methyl-N-dodecanoylglucamide in the reaction mixture. Obtained in the ratio of 40-50 weight%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 2

215 g of N-methylglucamine and 242 g of methyl tetradecanoate were added to the same apparatus as in Example 1, 200 g of methanol was added thereto, 7 g of potassium carbonate was added thereto, and the mixture was heated to reflux. As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. At this time, the condenser was removed and a distillation apparatus was installed to continuously remove methanol and heated to 130-140 ° C. If methanol is not generated, the reaction is considered to be terminated, and the reaction mixture is diluted with 500 g of 3.4% by weight aqueous sodium 2-chloroacetate solution to form N-methyl-N-tetradecanoyl lucamide in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 3

195 g of N-methylglucamine and 297 g of methylhexadecanoate were added to the same apparatus as in Example 1, 230 g of methanol was added thereto, 6 g of sodium methoxide was added thereto, and the mixture was heated to reflux. As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. At this time, the condenser was removed and a distillation apparatus was installed to continuously remove methanol and heated to 130-140 ° C. If methanol is not generated, the reaction is considered to be terminated, and the reaction mixture is diluted with 800 g of 1% by weight aqueous sodium 2-chloroacetate solution to form N-methyl-N-hexadecanoylglucamide in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 4

195 g of N-methylglucamine and 298 g of methyloctadecanoate were added to the same apparatus as in Example 1, 250 g of methanol was added thereto, 6 g of potassium carbonate was added thereto, and the mixture was heated to reflux. As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. At this time, the condenser was removed and a distillation apparatus was installed to continuously remove methanol and heated to 130-140 ° C. If no methanol is generated, the reaction is considered to be terminated, and the reaction mixture is diluted with 900 g of 1% by weight aqueous sodium 2-chloroacetate solution to form N-methyl-N-octadecanoylglucamide in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 5

In a 4-necked flask equipped with a mechanical stirrer, thermometer, and distillation apparatus, 205 g of N-methylglucamine, 214 g of methyl dodecanoate, and 5 g of potassium carbonate were heated to 120-150 ° C. Removal was continued. As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. If methanol is not generated, the reaction is considered to be terminated, and the reaction mixture is diluted with 500 g of 2.3% by weight aqueous sodium 2-chloroacetate solution to form N-methyl-N-dodecanoyl lucamide in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 6

195 g of N-methylglucamine, 266 g of methyl tetradecanoate, and 8 g of sodium methoxide were added to the same apparatus as in Example 5, and methanol generated during the reaction was continuously removed using a distillation apparatus while heating to 120-150 ° C. . As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. If no methanol is generated, the reaction is considered to be terminated, the reaction mixture is distilled off with 500 g of 1% by weight aqueous sodium 2-chloroacetate solution, and N-methyl-N-tetradecanoylglucamide is 40-50 weight in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 7

215 g of N-methylglucamine, 270 g of methyl hexadecanoate and 8 g of potassium carbonate were added to the same apparatus as in Example 5, and methanol generated during the reaction was continuously removed using a distillation apparatus while heating to 120-150 ° C. As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. If methanol is not generated, the reaction is considered to be terminated, and the reaction mixture is distilled off with 800 g of 2.3% by weight aqueous sodium 2-chloroacetate solution, and N-methyl-N-hexadecanoylglucamide is 30 to 40 weight in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

Example 8

215 g of N-methylglucamine, 298 g of methyloctadecanoate and 7 g of sodium methoxide were added to the same apparatus as in Example 5, and methanol generated during the reaction was continuously removed using a distillation apparatus while heating to 120-150 ° C. . As the reaction proceeded gradually, the reaction became a pale yellow transparent liquid. If methanol is not generated, the reaction is considered to be terminated, the reaction mixture is distilled off with 900 g of 2% by weight aqueous sodium 2-chloroacetate solution, and N-methyl-N-octadecanoylglucamide is 30 to 40 weight in the reaction mixture. Obtained at a rate of%. The content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in this reaction mixture was less than 1% by weight.

As described above, according to the method of the present invention, in the dilution step, ω-haloalkanoate is added to treat unreacted N-alkyl polyhydroxy amine and the unreacted fatty acid alkyl ester is hydrolyzed by the alkali catalyst used in the reaction. This results in a very small content of N-alkyl polyhydroxy amines and fatty acid alkyl esters remaining in the final reaction mixture, which results in no odor and is a surfactant of the desired N-acyl-N-alkyl polyhydroxy fatty acid amides. There is no influence on physical properties as well, so that a high quality natural N-acyl-N-alkyl polyhydroxy fatty acid amide surfactant can be obtained.

Claims (17)

After the N-alkyl polyhydroxy amine is reacted with the fatty acid alkyl ester under an alkali catalyst, ω-haloalkanoate is added to treat the unreacted N-alkyl polyhydroxy amine, and the unreacted fatty acid alkyl ester is added to the alkali catalyst. A method for producing N-acyl-N-alkyl polyhydroxy fatty acid amides having a very low residual amount of unreacted N-alkyl polyhydroxy amines and fatty acid alkyl esters, characterized by hydrolysis to convert to alkanoates. The method according to claim 1, wherein the N-acyl-N-alkyl polyhydroxy fatty acid amide prepared is a compound represented by the following general formula (1): [Formula 1] In the above formula, R represents straight or branched chain alkyl or alkenyl having 7 to 17 carbon atoms, R 'represents alkyl or hydroxyalkyl having 1 to 4 carbon atoms, Z represents a straight chain polyhydroxyalkyl having three or more hydroxy groups. The method of claim 1 wherein the fatty acid alkyl ester is a fatty acid alkyl ester having a straight or branched chain alkyl group having 7 to 17 carbon atoms. 4. The process of claim 3 wherein the fatty acid alkyl ester is methyloctanoate, methyldecanoate, methyldodecanoate, methyltetradecanoate, methylhexadecanoate or methyloctadecanoate or mixtures thereof. The method of claim 1 wherein the N-alkyl polyhydroxy amine is N-methyl, ethyl, propyl or butyl glucamine or N-methyl, ethyl, propyl or butyl maltamine or mixtures thereof. The process according to claim 1, wherein the N-alkyl polyhydroxy amine is used in a ratio of 0.8 to 1.3 equivalents to 1 equivalent of fatty acid alkyl ester. 7. The process according to claim 6, wherein the N-alkyl polyhydroxy amine is used in a ratio of 0.9 to 1.1 equivalents to 1 equivalent of fatty acid alkyl ester. The process of claim 1 wherein the alkali catalyst is selected from sodium carbonate, potassium carbonate, sodium methoxide, potassium hydroxide and sodium hydroxide. The method of claim 1, wherein the alkali catalyst is used in a proportion of 0.1 to 5% by weight of the total weight of the reaction mixture. 10. The process according to claim 9, wherein the alkali catalyst is used in a proportion of 0.5 to 2% by weight of the total weight of the reaction mixture. The process of claim 1 wherein the reaction is carried out in the presence of a solvent. The process according to claim 11, wherein methanol is used as a solvent in a proportion of 5 to 80% by weight of the total weight of the reaction mixture. The method of claim 11, wherein the reaction is carried out at a temperature of 65-80 ° C. for 1-5 hours. The process according to claim 1, wherein the reaction is carried out for 1 to 5 hours at a reaction temperature of 80 to 160 ° C in the absence of a solvent. The process according to claim 1, wherein sodium 2-chloroacetate, sodium 3-chloropropionate, potassium 2-chloroacetate or potassium 3-chloropropionate is used as ω-haloalkanoate. The method according to claim 1, wherein after the reaction is carried out using an excess of fatty acid alkyl ester relative to N-alkyl polyhydroxy amine, ω-haloalkanoate is 0.01 to 0.05 for 1 equivalent of N-alkyl polyhydroxy amine. Method of use in ratio of equivalents. 2. The reaction according to claim 1, wherein the reaction is carried out using an excess of N-alkyl polyhydroxy amine compared to fatty acid alkyl ester, and then ω-haloalkanoate is 0.05 to 0.1 for 1 equivalent of N-alkyl polyhydroxy amine. Method of use in the ratio of equivalents.