阅读说明：本技术 一种低磷月桂酰基肌氨酸钠的生产方法 (Production method of low-phosphorus sodium lauroyl sarcosinate ) 是由 陈绍伟 于 2021-08-31 设计创作，主要内容包括：本发明提供了一种低磷月桂酰基肌氨酸钠的生产方法,包括以下步骤：S1月桂酰氯的制备、S2生物除磷、S3缩合反应、S4酸化熟化、S5中和。本发明的低磷月桂酰基肌氨酸钠的生产方法,能够减少产品中磷离子的含量。(The invention provides a production method of low-phosphorus sodium lauroyl sarcosinate, which comprises the following steps: the method comprises the following steps of S1 preparation of lauroyl chloride, S2 biological phosphorus removal, S3 condensation reaction, S4 acidification and curing, and S5 neutralization. The production method of the low-phosphorus sodium lauroyl sarcosinate can reduce the content of phosphorus ions in the product.)

1. A production method of low-phosphorus sodium lauroyl sarcosinate is characterized by comprising the following steps:

preparation of S1 lauroyl chloride: adding lauric acid and phosphorus chloride into a reaction kettle, reacting for 2.5-3 hours at the temperature of 55-60 ℃, standing and layering to obtain an upper-layer solution, wherein the upper-layer solution contains lauroyl chloride and a small amount of phosphorous acid;

s2 biological phosphorus removal: preparing a treatment tank, placing an ultrafiltration membrane in the middle of the inner side of the treatment tank, filling a carrier solution mixed with phosphorus accumulating bacteria into one side of the ultrafiltration membrane, filling the upper-layer solution obtained in the step S1 into the other side of the ultrafiltration membrane, and reducing the content of phosphorous acid in the upper-layer solution by absorbing phosphorus by the phosphorus accumulating bacteria;

s3 condensation reaction: adding sodium sarcosinate, a sodium hydroxide solution and water into another reaction kettle, slowly adding the upper-layer solution subjected to the biological phosphorus removal treatment in the step S2 while stirring, ensuring that the temperature of a reaction system is not higher than 10 ℃, continuously stirring for 20-30 min, raising the temperature to 60-70 ℃, and stirring for 20-30 min to obtain a coarsened substance containing sodium lauroyl sarcosinate;

s4 acidification and curing: placing the coarsened substance in an acidification tank, adding a hydrochloric acid solution, stirring for 20-30 min, introducing gaseous hydrogen chloride, and continuing to react for 10-20 min to obtain an acidic mixture containing lauroyl sarcosine;

s5 neutralization: and adding a sodium hydroxide solution, adjusting the pH value to 7.1-7.5, and filtering and drying to obtain sodium lauroyl sarcosinate.

2. The method for producing low-phosphorous sodium lauroyl sarcosinate according to claim 1, wherein the carrier solution is one of lauroyl chloride, sodium lauroyl sarcosinate, sodium hydroxide solution and water.

3. The method for producing sodium lauroyl sarcosinate according to claim 2, wherein the carrier solution is water, and the water is removed by subsequent distillation, drying or the like.

4. The method for producing low-phosphorus sodium lauroyl sarcosinate according to claim 1, wherein in the biological phosphorus removal of step S2, two stirring devices are further arranged at the upper side of the treatment tank, and the two stirring devices continuously stir the carrier solution and the upper layer solution at a low speed for 5-10 hours.

5. The method for producing the low-phosphorus sodium lauroyl sarcosinate according to claim 1, wherein the pore diameter of micropores in the ultrafiltration membrane is less than 5 nm.

6. The method for producing sodium lauroyl sarcosinate according to claim 1, wherein the molar mass ratio of the hydrochloric acid solution to the gaseous hydrogen chloride is 1: 0.8-0.95.

7. The method for producing sodium lauroyl sarcosinate according to claim 1, wherein a small amount of alcohol antifoaming agent is added before neutralization in step S5.

8. The method for producing sodium lauroyl sarcosinate according to claim 7, wherein said alcohol antifoaming agent is one selected from the group consisting of fatty alcohol and triethanolamine.

Technical Field

The invention relates to the technical field of surfactants, in particular to a production method of low-phosphorus sodium lauroyl sarcosinate.

Background

Sodium lauroyl sarcosinate is an anionic surfactant with mild property, strong foaming power, good water solubility and excellent hard water resistance. Sodium lauroyl sarcosinate is commonly used in bath lotion, laundry detergent, soap and other washing and care products. The synthesis of lauroyl sarcosine sodium comprises the steps of preparing lauroyl chloride through reaction of lauric acid and phosphoryl chloride, performing condensation reaction of sodium sarcosine and sodium hydroxide solution with lauroyl chloride, and finally performing acidification and neutralization reaction.

Because the generated phosphorous acid is remained in the lauroyl chloride after the lauric acid and the phosphorus chloride are subjected to acylation reaction, phosphorus ions in a final product are difficult to remove, so that the phosphorus content in the product is high, and after the lauroyl sarcosine sodium is prepared into a washing and protecting product and is discharged into a river, the phosphorus is discharged into the river to easily cause excessive growth of algae in water, so that the environmental impact is great.

Disclosure of Invention

Aiming at the problems, the invention provides a production method of low-phosphorus sodium lauroyl sarcosinate, which can reduce the content of phosphorus ions in a product.

In order to achieve the purpose, the invention is solved by the following technical scheme:

a production method of low-phosphorus sodium lauroyl sarcosinate comprises the following steps:

preparation of S1 lauroyl chloride: adding lauric acid and phosphorus chloride into a reaction kettle, reacting for 2.5-3 hours at the temperature of 55-60 ℃, standing and layering to obtain an upper-layer solution, wherein the upper-layer solution contains lauroyl chloride and a small amount of phosphorous acid;

s2 biological phosphorus removal: preparing a treatment tank, placing an ultrafiltration membrane in the middle of the inner side of the treatment tank, filling a carrier solution mixed with phosphorus accumulating bacteria into one side of the ultrafiltration membrane, filling the upper-layer solution obtained in the step S1 into the other side of the ultrafiltration membrane, and reducing the content of phosphorous acid in the upper-layer solution by absorbing phosphorus by the phosphorus accumulating bacteria;

s3 condensation reaction: adding sodium sarcosinate, a sodium hydroxide solution and water into another reaction kettle, slowly adding the upper-layer solution subjected to the biological phosphorus removal treatment in the step S2 while stirring, ensuring that the temperature of a reaction system is not higher than 10 ℃, continuously stirring for 20-30 min, raising the temperature to 60-70 ℃, and stirring for 20-30 min to obtain a coarsened substance containing sodium lauroyl sarcosinate;

s4 acidification and curing: placing the coarsened substance in an acidification tank, adding a hydrochloric acid solution, stirring for 20-30 min, introducing gaseous hydrogen chloride, and continuing to react for 10-20 min to obtain an acidic mixture containing lauroyl sarcosine;

s5 neutralization: and adding a sodium hydroxide solution, adjusting the pH value to 7.1-7.5, and filtering and drying to obtain sodium lauroyl sarcosinate.

Specifically, the carrier solution is one of lauroyl chloride, sodium lauroyl sarcosinate, sodium hydroxide solution and water.

Specifically, the carrier solution is water, and the water is removed by means of subsequent distillation, drying and the like.

Specifically, in the step S2 of biological phosphorus removal, the upper side of the treatment tank is further provided with two stirring devices, the two stirring devices continuously and slowly stir the carrier solution and the upper layer solution respectively, and the stirring time is 5-10 hours.

Specifically, the pore diameter of micropores in the ultrafiltration membrane is less than 5 nanometers.

Specifically, the molar mass ratio of the hydrochloric acid solution to the gaseous hydrogen chloride is 1: 0.8-0.95.

Specifically, a small amount of alcohol antifoaming agent is added before neutralization in step S5.

Specifically, the alcohol defoaming agent is selected from one of fatty alcohol and triethanolamine.

The invention has the beneficial effects that:

1. the production method of low-phosphorus sodium lauroyl sarcosinate provided by the invention adds a biological phosphorus removal process, and reduces the content of phosphorous acid in an upper solution by absorbing phosphorus by phosphorus-accumulating bacteria, thereby reducing the phosphorus content of a sodium lauroyl sarcosinate product;

2. in the conventional process flow, an excessive hydrochloric acid solution is usually directly added into a crude product, however, the excessive hydrochloric acid is added, so that a large amount of sodium chloride is generated after subsequent neutralization reaction, and in order to reduce the content of the sodium chloride in a subsequent product, the content of HCl is reduced to the maximum extent by matching acidification of the hydrochloric acid solution and hydrogen chloride gas;

3. because sodium lauroyl sarcosinate is a surfactant which can easily generate foam, a large amount of foam can be generated in the production process, and manual defoaming or standing defoaming is needed subsequently.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments in order to provide a further understanding of the nature and technical means of the invention, as well as the specific objects and functions attained by the invention.

Example 1

A production method of low-phosphorus sodium lauroyl sarcosinate comprises the following steps:

preparation of S1 lauroyl chloride: adding lauric acid and phosphorus chloride into a reaction kettle, reacting for 2.5 hours at the temperature of 60 ℃, standing and layering to obtain an upper-layer solution, wherein the upper-layer solution contains lauroyl chloride and a small amount of phosphorous acid;

the reactions that occur in this process are as follows: 3C₁₁H₂3COOH+PCl₃→3C₁₁H₂₃COCl+H₃PO₃；

S2 biological phosphorus removal: preparing a treatment tank, wherein an ultrafiltration membrane with a micropore diameter smaller than 5 nanometers is placed in the middle of the inner side of the treatment tank, water mixed with phosphorus-accumulating bacteria is filled into one side of the ultrafiltration membrane, the ultrafiltration membrane can prevent the phosphorus-accumulating bacteria from passing through, the upper-layer solution obtained in the step S1 is filled into the other side of the ultrafiltration membrane, two stirring devices are further arranged on the upper side of the treatment tank, the two stirring devices are used for continuously stirring the carrier solution and the upper-layer solution at a low speed for 8 hours respectively, the content of the phosphorous acid in the upper-layer solution is reduced through the absorption of the phosphorus-accumulating bacteria on the phosphorus, and the treatment tank can be arranged in an environment with high oxygen content in order to accelerate the phosphorus ion uptake speed of the phosphorus-accumulating bacteria;

s3 condensation reaction: adding sodium sarcosinate, sodium hydroxide solution and water into another reaction kettle, slowly adding the upper-layer solution subjected to the biological phosphorus removal treatment in the step S2 while stirring, ensuring that the temperature of a reaction system is not higher than 10 ℃, continuously stirring for 30min, raising the temperature to 60 ℃, and stirring for 20min to obtain a coarsened substance containing sodium lauroyl sarcosinate;

the reactions that occur in this process are as follows:

CH₃NHCH₂COONa+3C₁₁H₂₃COCl+NaOH→NaCl+H₂O+C₁₁H₂₃CON(CH₃)CH₂COONa；

s4 acidification and curing: because sodium sarcosinate generally contains a small amount of methylamine which is a harmful gas, in order to remove the residual small amount of methylamine in the product obtained after the step S3, the step is also needed to be carried out, the methylamine is removed by acidification, sodium lauroyl sarcosinate is converted into lauroyl sarcosine again by curing acid, in addition, in the conventional process flow, an excessive hydrochloric acid solution is usually directly added into the coarse product, however, the excessive hydrochloric acid is added, so that a large amount of sodium chloride is generated after the subsequent neutralization reaction, in the embodiment, in order to reduce the content of sodium chloride in the subsequent product, the content of HCl is reduced to the maximum extent by the coordination acidification of the hydrochloric acid solution and the hydrogen chloride gas, the specific operation is that the coarse product is firstly placed in an acidification tank, the hydrochloric acid solution is added, the molar mass ratio of the hydrochloric acid solution to the gaseous hydrogen chloride is 1:0.9, and after the stirring is carried out for 20min, introducing gaseous hydrogen chloride, and continuously reacting for 15min to obtain an acidic mixture containing lauroyl sarcosine;

the reactions that occur in this process are as follows:

C₁₁H₂₃CON(CH₃)CH₂COONa+HCl→NaCl+H₂O+C₁₁H₂₃CON(CH₃)CH₂COOH+NaCl；

s5 neutralization: firstly, adding a small amount of fatty alcohol, adding the fatty alcohol, effectively reducing foam generated by continuous stirring of a product in the reaction process, then adding a sodium hydroxide solution, adjusting the pH value to 7.1-7.5, and filtering and drying to obtain sodium lauroyl sarcosinate;

the reactions that occur in this process are as follows:

C₁₁H₂₃CON(CH₃)CH₂COOH+NaOH→C₁₁H₂₃CON(CH₃)CH₂COONa+H₂O。

the above examples only show 1 embodiment of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.