WO2023093560A1 - Method for preparing n-fatty acyl amino acid surfactant by means of high-temperature melting and direct condensation - Google Patents

Abstract

The present invention discloses a method for preparing an N-fatty acyl amino acid surfactant by means of high-temperature melting and direct condensation. The method of the present invention comprises: mixing a fatty acid, a catalyst and an amino acid, heating same to a molten state for a reaction, and then subjecting same to dehydration condensation to obtain the N-fatty acyl amino acid surfactant. The method avoids the use of acyl chloride as in the traditional method; the resulting product does not contain any salt; and the method has the advantages of a simple operation, an excellent product performance, environmental friendliness, etc.

Description

A kind of high-temperature melting direct condensation prepares the method for N-fatty acyl amino acid surfactant technical field

The invention relates to the field of chemical synthesis, in particular, the invention relates to a method for preparing N-fatty acyl amino acid surfactant through direct condensation at high temperature.

Background technique

N-fatty acyl amino acid type anionic surfactant has a hydrophilic amino acid group, which is a safe surfactant with excellent water solubility, foaming property, acid and alkali resistance, and fatty acid Better hard water stability than soap. The pH value of N-fatty acyl amino acid surfactant is close to neutral and slightly acidic, which is very close to the pH value of human skin, which can make the skin feel comfortable and soft. It is widely used in various liquids, creams, facial cleansers, masks, In various daily chemical products such as skin care products, toothpaste, shampoo, shower gel, etc., it is especially suitable for children's safe washing hygiene products and detergents for fruits, protein fibers, and tableware.

The preparation of N-fatty acyl amino acid surfactants has two kinds of indirect method and direct method. The indirect method is to adopt the Schotton-Bowman condensation reaction to obtain products from fatty acid chlorides and amino acid salts under alkaline conditions. It is a commonly used method in current industrial production. At the same time, a large amount of salt is difficult to recycle, which will cause product loss during multiple recrystallization and purification processes. The direct method is the direct dehydration condensation of fatty acids and amino acids (salts) to obtain products. The preparation process does not require acyl chloride reaction, and the product does not need desalination treatment. The process cycle is short, green and safe, and the loss of materials is small. It has a good prospect for industrial production.

The direct method is the direct dehydration condensation of fatty acids (esters, anhydrides, etc.) and amino acids (salts) to obtain products. With the concept of "green chemistry" being put forward, people require chemical products to be produced with green and environmentally friendly processes in terms of reaction and design. The direct method has a good prospect for industrial production because the preparation process does not require acyl chloride reaction, and the product does not need desalination treatment, the process cycle is short, green and safe, and the loss of materials is small. At present, the direct method research is based on the direct condensation method of fatty acid raw materials. In related research, such as patent CN105175290A, molten paraffin is used as the reaction solvent to prepare sodium lauroyl methyl taurate through the direct condensation method of lauric acid. This method has the difficulty of paraffin separation. Problem; adopt microwave heating method direct condensation to prepare N-acyl-N-methyl taurate in the patent CN106588710A, although have avoided the use of solvent, microwave heating has also limited its suitability for industrialized production; In the method, all materials need to be subjected to separation steps such as crystallization, filtration, and centrifugation at high temperatures, which have very high requirements for equipment and safety, and long-term high-temperature operation consumes a lot of energy and is prone to side reactions, and the color of the obtained product is relatively yellow.

In order to overcome the shortcomings of the prior art, it is urgently needed in this field to find a preparation method of N-fatty acyl amino acid surfactants with simple operation, high yield, convenient post-treatment, green safety, and suitability for industrialized production, so as to promote such Wide application of technology in daily chemical field.

Contents of the invention

The purpose of the present invention is to provide a method for preparing N-fatty acyl amino acid surfactant by high-temperature melting direct condensation.

A first aspect of the present invention provides a method for preparing N-fatty acyl amino acid surfactants through direct condensation of high-temperature melting, comprising the steps of:

(a) providing a raw material mixture containing raw materials (i) fatty acids, (ii) amino acids or salts thereof, and (iii) catalysts;

(b) reacting the raw material mixture in a molten state to obtain a reaction mixture containing N-fatty acyl amino acid surfactant;

In the formula,

R ₁ is an alkyl group of C ₆ -C ₂₂ saturated or unsaturated, linear or branched fatty acid;

R ₂ is H or CH ₃ ;

R ₃ is H, C1-C6 branched or straight-chain alkanes, hydroxyl-substituted C ₁ -C ₃ alkanes, or COOH;

n is a positive integer ranging from 1 to 5;

X is COONa, COOK, COOH, SO ₃ Na, SO ₃ K, SO ₃ H, or SO ₃ NH ₃ ;

(c) reducing the temperature of the reaction mixture, thereby forming a crude product containing N-fatty acyl amino acid surfactant, which is a bulk crude product; and

(d) performing a subsequent purification treatment on the crude product, thereby obtaining a purified N-fatty acyl amino acid surfactant;

Wherein, described N-fatty acyl amino acid surfactant is as shown in formula I:

In the formula, R ₁ , R ₂ , R ₃ , X and n are as defined above.

In another preferred example, the raw amino acid or its salt is in the form of an aqueous solution of the amino acid or its salt.

In another preferred example, the amino acid or its salt in the raw amino acid or its salt accounts for ≥20% by weight; preferably ≥30%, more preferably ≥40%.

In another preferred example, the "consisting essentially of (i) raw fatty acids, (ii) amino acids or salts thereof, and (iii) catalysts" indicates that components (i), (ii) and (iii) account for The total weight of the mixture is ≥95%, preferably ≥98%, more preferably ≥99%.

In another preferred embodiment, in step (a), the raw amino acid or its salt is slowly added dropwise to the molten fatty acid and catalyst.

In another preferred example, the molten state is 120-300°C.

In another preferred example, in step (b), the reaction in the molten state is carried out under nitrogen.

In another preferred embodiment, in step (c), the temperature of the reaction mixture is lowered, thereby forming the lumpy crude product.

In another preferred example, in step (c), the mass of the lumpy crude product is 20-50000g, preferably 30-20000g, more preferably 1000-15000g.

In another preferred embodiment, the reaction mixture is cooled to room temperature (eg, 4-25° C.).

In another preferred embodiment, in step (d), the crude product is washed with a first solvent to obtain a purified N-fatty acyl amino acid surfactant.

In another preferred embodiment, in step (d), the crude product is recrystallized with the first solvent to obtain a purified N-fatty acyl amino acid surfactant.

In another preferred example, in step (d), it also includes drying the purified N-fatty acyl amino acid surfactant to obtain a dried N-fatty acyl amino acid surfactant product.

In another preferred example, the purity of the N-fatty acyl amino acid surfactant is ≥90%; preferably ≥93%.

In another preferred example, the dried N-fatty acyl amino acid surfactant product is in powder form.

In another preferred example, in step (c), the cooling is natural cooling for 1-2 hours.

In another preferred embodiment, in step (d), the purification treatment is selected from the group consisting of washing, recrystallization, or a combination thereof.

In another preferred example, in step (d), the purification process uses a first solvent selected from the group consisting of water, C ₂ -C ₆ alcohol solvents, C ₄ -C ₆ alkanes solvents, or combination.

In another preferred example, the C ₂ -C ₆ alcohol solvent is selected from the group consisting of ethanol, isopropanol, or combinations thereof.

In another preferred example, the C ₄ -C ₆ alkane solvent is selected from the group consisting of n-hexane, dichloromethane, or combinations thereof.

In another preferred embodiment, the first solvent is selected from the group consisting of water, isopropanol, petroleum ether, or combinations thereof.

In another preferred example, the first solvent is water.

In another preferred example, the first solvent is isopropanol.

In another preferred example, the first solvent is petroleum ether.

In another preferred example, the purification treatment is to wash the crude product with isopropanol.

In another preferred embodiment, the purification treatment is to recrystallize the crude product with water

In another preferred embodiment, in step (a), the catalyst is selected from the group consisting of metal oxides, metal chlorides, boric acid-based catalysts, phosphorus-based catalysts, or combinations thereof.

In another preferred embodiment, the metal oxide is selected from the group consisting of zinc oxide, calcium oxide, or a combination thereof.

In another preferred embodiment, the metal chloride is selected from the group consisting of ferric chloride, magnesium chloride, or a combination thereof.

In another preferred embodiment, the boric acid-based catalyst is selected from the group consisting of boric acid, 2-chlorophenylboronic acid, or a combination thereof.

In another preferred embodiment, the phosphorus-based catalyst is selected from the group consisting of hypophosphorous acid, sodium hypophosphite, phosphoric acid, or combinations thereof.

In another preferred embodiment, in step (a), the fatty acid R ₁ COOH is selected from the group consisting of oleic acid, lauric acid, stearic acid, palmitoleic acid, myristic acid, coconut oil acid, or combinations thereof.

In another preferred example, in step (a), the amino acid or its salt is selected from the group consisting of sodium glycinate, sodium glutamate, sodium alanine, sodium sarcosinate, or combinations thereof.

In another preferred example, in step (a), the molar ratio of fatty acid to amino acid is 0.5-3.5:0.5-3.5, preferably, 0.7-2:0.7-2.

In another preferred example, the mass ratio of the fatty acid to the catalyst is 1:0.001-0.1, preferably 1:0.006-0.06.

In another preferred example, in step (b), the reaction time is 3-15 hours, preferably, the reaction time is 4-10 hours.

In another preferred example, the reaction temperature is 120°C-300°C, preferably, the reaction temperature is 250°C±5°C.

It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (such as embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, we will not repeat them here.

Description of drawings

Fig. 1 has shown the physical picture of the crude product of sodium cocoyl methyl taurate prepared in embodiment 1 of the present invention.

Fig. 2 has shown the physical picture of the sodium cocoyl methyl taurate purification product prepared in embodiment 1 of the present invention.

Detailed ways

After extensive and in-depth research and a large number of screenings, the present inventors first developed a method for preparing N-fatty acyl amino acid surfactants with simple process flow, simple subsequent purification treatment, high yield and high purity. The preparation method of the invention has the advantages of simple operation, low energy consumption, environmental protection, high yield and is suitable for large-scale industrial production. The present invention has been accomplished on this basis.

The test shows that, adopting the method of the present invention, the bulk crude product is obtained by lowering the temperature after the reaction is finished. After crushing, washing or recrystallization in a solvent and drying, a powder product with a purity of more than 95% is obtained, which is suitable for large-scale preparation of high-purity N-fatty acyl amino acid surfactants.

high temperature melting direct condensation method

A method for preparing N-fatty acyl amino acid surfactant through high-temperature melting direct condensation, comprising the steps of:

(a) providing a raw material mixture containing raw materials (i) fatty acids, (ii) amino acids or salts thereof, and (iii) catalysts;

(b) reacting the raw material mixture in a molten state to obtain a reaction mixture containing N-fatty acyl amino acid surfactant;

In the formula,

R ₁ is an alkyl group of C ₆ -C ₂₂ saturated or unsaturated, linear or branched fatty acid;

R ₂ is H or CH ₃ ;

R ₃ is H, C ₁ -C ₆ branched or straight-chain alkane, hydroxyl-substituted C ₁ -C ₃ alkane, or COOH;

n is a positive integer ranging from 1 to 5;

X is COONa, COOK, COOH, SO ₃ Na, SO ₃ K, SO ₃ H, or SO ₃ NH ₃ ;

(c) reducing the temperature of the reaction mixture, thereby forming a crude product containing N-fatty acyl amino acid surfactant, which is a bulk crude product; and

(d) performing a subsequent purification treatment on the crude product, thereby obtaining a purified N-fatty acyl amino acid surfactant;

Wherein, described N-fatty acyl amino acid surfactant is as shown in formula I:

In the formula, R ₁ , R ₂ , R ₃ , X and n are as defined above.

In one embodiment, the raw amino acid or its salt is in the form of an aqueous solution of the amino acid or its salt.

In another embodiment, the amino acid or its salt in the raw amino acid or its salt accounts for ≥20% by weight; preferably ≥30%, more preferably ≥40%.

In another embodiment, said "consisting essentially of (i) raw fatty acids, (ii) amino acids or salts thereof, and (iii) catalysts" indicates that components (i), (ii) and (iii) account for The total weight of the mixture is ≥95%, preferably ≥98%, more preferably ≥99%.

In another embodiment, in step (a), the raw amino acid or its salt is slowly added dropwise into the molten fatty acid and the catalyst.

In another embodiment, said molten state is 120-300°C.

In another embodiment, in step (b), said reaction in molten state is carried out under nitrogen.

In another embodiment, in step (c), the temperature of the reaction mixture is lowered to form the lumpy crude product.

In another embodiment, in step (c), the mass of the lumpy crude product is 20-50000g, preferably 30-20000g, more preferably 1000-15000g.

In another embodiment, the reaction mixture is cooled to room temperature (eg, 4-25°C).

In another embodiment, in step (d), the crude product is washed with a first solvent to obtain a purified N-fatty acylamino acid surfactant.

In another embodiment, in step (d), the crude product is recrystallized from the first solvent to obtain a purified N-fatty acyl amino acid surfactant.

In another embodiment, in step (d), further comprising drying the purified N-fatty acyl amino acid surfactant to obtain a dried N-fatty acyl amino acid surfactant product.

In another embodiment, said N-fatty acylamino acid surfactant has a purity > 90%; preferably > 93%.

In another embodiment, the dried N-fatty acyl amino acid surfactant product is in powder form.

In another embodiment, in step (c), the cooling is natural cooling for 1-2 hours.

In another embodiment, in step (d), the purification treatment is selected from the group consisting of washing, recrystallization, or a combination thereof.

In another embodiment, in step (d), the purification process uses a first solvent selected from the group consisting of water, C ₂ -C ₆ alcohol solvents, C ₄ -C ₆ alkanes solvents, or combination.

Compared with prior art, the advantages of the present invention:

(1) The method of the present invention avoids the use of acid chlorides in traditional methods, and is environmentally friendly

(2) The crude product prepared by the present invention does not contain or basically does not contain salt, and the post-treatment is more convenient and efficient.

(3) The catalyst of the inventive method is cheap and easy to get, safe and harmless.

(4) The method of the present invention is simple to operate, the process flow time is short, and the safety performance is high.

(5) The method of the present invention can obtain high-yield, high-purity N-fatty acyl amino acid surfactants.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed. Percentages and parts are by weight unless otherwise indicated.

In the examples, room temperature refers to 25°C.

The raw materials and reagents used in the examples are all commercially available products.

Example 1

Add coconut oil acid (25g) and boric acid (1g) in the preheating still, under stirring, gradually add sodium methyl taurate aqueous solution (40g, concentration 40%) dropwise, after fully stirring, the temperature of reaction solution is gradually warming up to Make it melt completely at 250°C and react for 7 hours to obtain a reaction mixture (liquid state) containing sodium cocoyl methyl taurate.

After the reaction was completed, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a light yellow lumpy crude product (40 g). The purity of sodium cocoyl methyl taurate in the crude product was 87% (yield 91%).

After the crude product is pulverized, it is recrystallized and dried in water (the mass ratio of solid to liquid is 1:2) to obtain purified sodium cocoyl methyl taurate (32g) as a white powder (purity 98% , yield 90%).

Example 2

Add oleic acid (25g) and calcium oxide (0.25g) in the preheating kettle, gradually dropwise add sodium glutamate aqueous solution (30g, concentration 40%) under stirring, gradually the temperature of reaction solution is warming up to 250 ℃, make it melt completely, and react for 5 hours to obtain a reaction mixture (liquid state) containing sodium oleoyl glutamate.

After the reaction, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a light yellow lumpy crude product (35 g), as shown in FIG. 1 . The purity of sodium oleoyl glutamate in the crude product was 83% (yield 88%).

After the crude product was pulverized, it was washed (about 20 minutes) and dried in isopropanol (solid-to-liquid mass ratio of 1:3) to obtain purified sodium oleoyl glutamate (27 g), as shown in Figure 2 It is shown as white powder (purity 95%, yield 89%).

Example 3

Add oleic acid (25g) and boric acid (1g) in the preheating still, gradually dropwise add sodium sarcosinate aqueous solution (30g, concentration 40%) under stirring, the temperature of reaction solution is gradually warming up to 250 ℃ after fully stirring, It was completely melted and reacted for 8 hours to obtain a reaction mixture (liquid state) containing sodium oleoyl sarcosinate.

After the reaction was completed, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a light yellow lumpy crude product (42 g). The purity of sodium oleoyl sarcosinate in the crude product was 88% (yield 89%).

After crushing the crude product, it was washed and dried in cyclohexane (solid-to-liquid mass ratio: 1:2) to obtain purified sodium oleoyl sarcosinate (35 g) as a white powder (purity 97%, yield rate of 92%).

Example 4

Add oleic acid (25g) and zinc oxide (0.5g) in the preheating kettle, gradually add dropwise sodium glycinate aqueous solution (30g, concentration 40%) under stirring, the temperature of reaction solution is gradually warming up to 250 ℃ after fully stirring, It was completely melted and reacted for 10 hours to obtain a reaction mixture (liquid state) containing sodium oleoyl glycinate.

After the reaction was completed, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a light yellow blocky crude product (37 g). The purity of sodium oleoyl glycinate in the crude product was 85% (yield 92%).

After pulverizing the crude product, it was washed and dried in isopropanol (solid-to-liquid mass ratio: 1:3) to obtain purified sodium oleoyl glycinate (30 g) as a white powder (purity 97%, yield 93 %).

Example 5

Add stearic acid (12.5g), lauric acid (12.5g) and calcium oxide (0.75g) in the preheating kettle, gradually add dropwise sodium alanine aqueous solution (20g, concentration 40%) under stirring, after fully stirring Gradually raise the temperature of the reaction liquid to 250° C. to make it melt completely, and react for 6 hours to obtain a reaction mixture (liquid state) containing sodium stearoyl lauroyl alanine.

After the reaction was completed, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a crude product (32 g) in the form of light yellow lumps. The purity of sodium stearoyl lauroyl alaninate in the crude product was 84% (yield 89%).

After the crude product was pulverized, it was washed and dried in isopropanol (solid-to-liquid mass ratio of 1:3) to obtain purified sodium stearoyl lauroyl alaninate (25 g) as a white powder (purity 96 %, yield 91%).

Example 6

Add stearic acid (25g) and boric acid (0.75g) in the preheating still, gradually dropwise add sodium glycinate aqueous solution (30g, concentration 40%) under stirring, the temperature of reaction solution is gradually warming up to 250 ℃ after fully stirring, It was completely melted and reacted for 10 hours to obtain a reaction mixture (liquid state) containing sodium stearyl glycinate.

After the reaction was completed, the reaction mixture was naturally cooled to room temperature (about 1 hour) to obtain a crude product (32 g) in the form of light yellow lumps. The purity of sodium stearyl glycinate in the crude product was 87% (yield 89%).

After pulverizing the crude product, it was washed and dried in isopropanol (the mass ratio of solid to liquid was 1:3) to obtain purified sodium stearyl glycinate (26 g) as a white powder (purity 97%, yield 90%).

Example 7

Preparation of 5-10kg grade

Add stearic acid (6200g) and boric acid (124g) in the preheating kettle, gradually add dropwise the aqueous solution (concentration 40%) of sodium alanine (7083.1g) under stirring, gradually the temperature of reaction solution is heated up after fully stirring Melt it completely at 250° C. and react for 6 hours to obtain a reaction mixture (liquid state) containing sodium stearyl alanine.

After the reaction was finished, the reaction mixture was naturally cooled to room temperature (about 2 hours) to obtain a light yellow block crude product (10025g). The purity of sodium stearyl alaninate in the crude product was 85% (yield 89%).

After the crude product was pulverized, it was recrystallized in water (solid-liquid mass ratio was 1:2) and dried to obtain purified sodium stearyl alaninate (8166.2 g) as a white powder (purity 96%, Yield 92%).

Example 8

The purified products of the above-mentioned Examples 1-7 were recrystallized and dried again in water (the mass ratio of solid to liquid was 1:2) to obtain secondary purified products with a purity of over 99%.

The raw material consumption of Examples 1-7 and the properties of prepared products are listed in Table 1.

Table 1 Different fatty acid, amino acid (salt) and catalyst consumption and product performance

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (14)

1. A method for preparing N-fatty acyl amino acid surfactant by direct condensation of high temperature melting, is characterized in that, comprises the steps:

   (a) providing a raw material mixture containing raw materials (i) fatty acids, (ii) amino acids or salts thereof, and (iii) catalysts;

   (b) reacting the raw material mixture in a molten state to obtain a reaction mixture containing N-fatty acyl amino acid surfactant;

   

   In the formula,

   R ₁ is an alkyl group of a C6-C22 saturated or unsaturated, linear or branched fatty acid;

   R ₂ is H or CH ₃ ;

   R ₃ is H, C1-C6 branched or straight-chain alkane, hydroxyl-substituted C1-C3 alkane, or COOH;

   n is a positive integer ranging from 1 to 5;

   X is COONa, COOK, COOH, SO ₃ Na, SO ₃ K, SO ₃ H, or SO ₃ NH ₃ ;

   (c) reducing the temperature of the reaction mixture, thereby forming a crude product containing N-fatty acyl amino acid surfactant, the crude product being a bulk crude product; and

   (d) performing a subsequent purification treatment on the crude product, thereby obtaining a purified N-fatty acyl amino acid surfactant;

   Wherein, described N-fatty acyl amino acid surfactant is as shown in formula I:

   

   In the formula, R ₁ , R ₂ , R ₃ , X and n are as defined above.
2. The method according to claim 1, characterized in that the raw material amino acid or its salt is slowly added dropwise into the molten fatty acid and the catalyst.
3. The method according to claim 1, characterized in that the molten state is 120-300°C.
4. The method according to claim 1, characterized in that, in step (c), said cooling is natural cooling for 1-2 hours.
5. The method according to claim 1, wherein in step (d), the purification treatment is selected from the group consisting of washing, recrystallization, or a combination thereof.
6. [Corrected under Rule 26 28.11.2022]
   The method according to claim 1, characterized in that, in step (d), the purification process uses a first solvent selected from the group consisting of water, C ₂ -C ₆ alcohol solvents, C ₄ -C ₆ Alkanes, or combinations thereof.
7. The method according to claim 6, wherein the first solvent is selected from the group consisting of water, isopropanol, petroleum ether, or combinations thereof.
8. The method according to claim 1, characterized in that, in step (a), the catalyst is selected from the group consisting of metal oxides, metal chlorides, boric acid catalysts, phosphorus-based catalysts, or combinations thereof.
9. The method of claim 8, wherein the metal oxide is selected from the group consisting of zinc oxide, calcium oxide, or combinations thereof.
10. The method according to claim 8, wherein the boric acid-based catalyst is selected from the group consisting of boric acid, 2-chlorophenylboronic acid, or a combination thereof.
11. The method according to claim 1, wherein in step (a), the fatty acid R ₁ COOH is selected from the group consisting of oleic acid, lauric acid, stearic acid, palmitoleic acid, myristic acid, coconut oil acid, or a combination thereof.
12. The method according to claim 1, wherein in step (a), the amino acid or its salt is selected from the group consisting of sodium glycinate, sodium glutamate, sodium alanine, sodium sarcosinate, or combination.
13. The method according to claim 1, characterized in that, in step (a), the molar ratio of the fatty acid to the amino acid is 0.5-3.5:0.5-3.5, preferably 0.7-2:0.7-2; and/ or

    The mass ratio of the fatty acid to the catalyst is 1:0.001-0.1, preferably 1:0.006-0.06.
14. The method according to claim 1, characterized in that, in step (b), the reaction time is 3-15 hours, preferably, the reaction time is 4-10 hours.

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