CN103804462B - The preparation method of tea saponin laurate tensio-active agent and product - Google Patents

Abstract

The invention discloses a preparation method of a tea saponin laurate surfactant, comprising: adding a catalyst, tea saponin and lauric acid chloride into an organic solvent, and carrying out an esterification reaction until the reaction is complete; post-processing to obtain tea Saponin Laurate Surfactant. The present invention also provides a surfactant prepared by the above preparation method. The preparation process of the invention is simple and environment-friendly, and the tea saponin laurate surfactant prepared by the method has better surface activity and better market prospects.

Description

Preparation method and product of tea saponin laurate surfactant

technical field

The invention relates to the technical field of surfactant preparation, in particular to a preparation method and product of a tea saponin laurate surfactant.

Background technique

Surfactants have the properties of dispersion, penetration, solubilization, and foaming, and are widely used in food, medicine, pesticides, daily chemicals, mineral processing, oil fields, etc., and their types and consumption are increasing day by day. However, people have been using artificially synthesized surfactants for a long time, which poses a greater threat to human health and the environment. Non-toxic, easily degradable surfactants have attracted more and more attention. Carboxylate surfactants can be synthesized from natural raw materials and are easy to biodegrade, so they have always been favored by people. However, common carboxylate anionic surfactants have the disadvantages of being unstable or even losing surface activity under acidic conditions.

Tea saponin, also known as tea saponin, is a class of oleanane-type pentacyclic triterpenoid saponins, composed of saponins, sugar bodies and organic acids, widely present in the roots, stems, leaves, and In flowers and fruits. Tea saponin is a natural surfactant with good performance. It can be widely used in light industry, chemical industry, pesticide, feed, breeding, textile, oil extraction, mining, building materials and highway construction and other fields. It is used to manufacture emulsifiers, Detergents, pesticide auxiliaries, feed additives, protection agents for crab and shrimp farming, textile auxiliaries, oilfield foam agents, mining flotation agents, air-entrained concrete foam stabilizers and concrete admixtures - antifreeze, etc. The output of camellia oleifera seeds in my country ranks first in the world. The content of tea saponin in the by-product camellia seed meal after extraction of tea oil can reach about 10%. Fully promoting the deep processing of tea saponin is very important for the comprehensive utilization of camellia oleifera resources. social and economic value.

Tea saponin is a natural nonionic surfactant with good performance. It has the properties of reducing the surface tension of water, emulsifying, dispersing, and wetting. The formed emulsion particles are small, evenly distributed, and stable; in addition, tea saponin It has strong foaming ability and good foam stabilizing performance. There are a large number of modifiable groups such as hydroxyl groups in the tea saponin molecule, which can expand its application range through chemical modification and overcome the deficiencies in the use of tea saponin. At present, there are more and more researches on the chemical modification of tea saponin. For example, the patent document with application publication number CN102030806A discloses a preparation method of tea saponin higher fatty acid ester, in the presence of a catalyst, tea saponin and higher fatty alcohol are mixed and reacted, and the catalyst is separated to obtain tea saponin higher fatty acid ester. fatty esters. The tea saponin higher fatty ester prepared by the above method is non-toxic and easy to degrade raw materials; more importantly, as a surfactant, it has stronger foaming power and foam stabilizing performance at high temperature and in oil; The existing tea saponin has the defects of poor foaming power and foam stabilizing performance in high temperature and oily environment. However, the above method uses a relatively expensive mixture of N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine as a catalyst, and the preparation cost is relatively high. The patent literature with the application publication number CN102030803A discloses a method for preparing tea saponin derivatives, which is prepared by the following steps: (1) react triphenylchloromethane with tea saponin; then, add benzyl bromide and tea saponin reaction; (2) react phosphorus tribromide with sugar; The deprotecting agent is reacted; then, in the presence of a catalyst, the benzyl deprotecting agent is added and reacted to obtain tea saponin derivatives. The tea saponin derivative prepared by the above preparation method is used as a surfactant, and has stronger foaming power and foam stabilizing performance in a high-salt and high-temperature environment. However, this method uses triphenylchloromethane, phosphorus tribromide and benzyl bromide, which are irritating and toxic, and has relatively high requirements on equipment, and the process is relatively complicated, so it is not suitable for industrial production.

To sum up, the above two modification methods for tea saponin have complicated processes and high preparation costs, and the prepared modified surfactants cannot meet the current various demands for surfactants. Therefore, it is of great significance to develop a multifunctional and environmentally friendly surfactant.

Contents of the invention

The invention provides a method for preparing a tea saponin laurate surfactant. The method has a simple preparation process and is environmentally friendly, and the tea saponin laurate surfactant prepared by the method has higher surface activity. It is suitable for separation and extraction of descaling agents and biofilm proteins and as emulsifier, and the reaction conditions are easy to control, and can be used for industrial production.

A preparation method of a tea saponin laurate surfactant, comprising: adding a catalyst, tea saponin and lauric acid chloride into an organic solvent to carry out an esterification reaction, and after the reaction is completed, post-processing to obtain tea saponin lauric acid ester surfactants.

In order to realize the separation of the final product tea saponin laurate, various post-treatment methods can be selected, for example, the product in the system can be separated by adjusting the pH value of the system liquid; for ease of operation, as a preferred technology Scheme, described post-processing method comprises:

(1) Acidify the reaction solution after the esterification reaction, adjust the pH value of the reaction solution to be less than or equal to 5, extract and remove unreacted lauric acid with a mixed solvent of petroleum ether and ethyl acetate, and then add the macroporous resin to the esterification In the reaction system after the reaction is completed, the macroporous resin is used to adsorb the tea saponin laurate therein, and after the adsorption is completed, filter to obtain the macroporous resin adsorbed with the tea saponin laurate;

(2) Dissolving the macroporous resin adsorbed with tea saponin laurate into a resolving agent, carrying out a resolving reaction, filtering, and removing the solvent in the resolving solution to obtain a tea saponin laurate surfactant.

Catalyst described in the present invention can be selected one or more in the commonly used acidic catalyst of esterification or basic catalyst; Commonly used acidic catalyst can be selected inorganic acid or organic acid, for example can select dilute hydrochloric acid, dilute sulfuric acid, acetic acid etc. Commonly used basic catalysts can be inorganic bases or organic bases, such as potassium carbonate, sodium carbonate, sodium hydroxide, sodium alkoxide, etc. for inorganic bases, and triethylamine, pyridine, or diethylamine for organic bases. Preferably, the catalyst is one or more of potassium carbonate, sodium carbonate and sodium hydroxide.

In the present invention, the organic solvent can be selected from a variety of solvents with good solubility for the reaction substrate. In order to facilitate the rapid reaction, the preferred organic solvents include N,N-dimethylformamide (DMF), One or more of dimethyl sulfoxide (DMSO), acetone, etc.

In the present invention, the temperature of the esterification reaction can be carried out at normal temperature, or can be properly heated. For the convenience of control, the temperature of the esterification reaction is preferably 20-30 degrees Celsius. If the temperature is too high, side reactions will easily occur, and high temperature conditions will increase the preparation cost and control difficulty. The reaction time of the esterification reaction varies according to the actual reaction substrate, and can be determined according to actual needs.

In the present invention, the molar weights of the added lauric acid chloride and the catalyst can be determined according to actual needs, and the degree of substitution of carboxyl groups on the tea saponin can be changed by controlling the addition of the above two, so as to obtain partial esterification or complete esterification. Sexual tea saponin esterification products to meet the needs of different use occasions. In order to avoid waste of raw materials and reduce the production cost of the tea saponin laurate surfactant, the molar ratio of the tea saponin, lauric acid chloride and catalyst is preferably 1:0.5-50:0.5-50. In order to further save raw materials, as a further preference, the molar ratio of the tea saponin, lauric acid chloride and catalyst added is preferably 1:1-20:1-20, and at normal temperature, the molar ratio of tea saponin and lauric acid chloride When the ratio reaches about 1:20, the reaction of the highly active hydroxyl group on the tea saponin is basically completed. Therefore, in order to avoid waste of raw materials, the molar ratio of the tea saponin, lauric acid chloride and catalyst is further preferably 1:5-15:5-20.

Macroporous resin, also known as fully porous resin, is prepared by polymerizing monomers and additives such as crosslinking agents, porogens, and dispersants. After the polymer is formed, the porogen is removed and remains in the resin. Holes of different sizes and shapes that interpenetrate with each other. Therefore, the macroporous resin has a relatively high porosity inside the dry state, and the pore diameter is relatively large, between 100-1000nm. In order to improve the adsorption efficiency of the macroporous resin to the target product, in the post-treatment process, the macroporous resin is generally selected from non-polar macroporous resin. Preferred non-polar macroporous resins include AB-8 type macroporous adsorption resin, which can selectively absorb tea saponin laurate obtained by the reaction, and the subsequent analysis process is efficient, easy to control. The quality of the added macroporous resin needs to be determined according to the actual adsorption effect. Generally, the complete adsorption of tea saponin laurate in the system shall prevail. The adsorption process can be monitored in real time by TLC until the adsorption is completed. When the concentration of the reaction solution after the esterification reaction is high, before adding the macroporous resin, the concentration of the reaction solution obtained by the esterification reaction can be properly diluted by adding water, so as to facilitate the uniform adsorption of the macroporous resin. Prevent impurities from being adsorbed synchronously due to excessive concentration. In the post-treatment process, the adsorption temperature is generally 20-35 degrees Celsius, which can be adjusted according to actual conditions.

In the post-processing process, the desorption temperature can be selected at room temperature, or can be properly heated. For the convenience of control, the desorption temperature is preferably 20-40 degrees Celsius, and it is more preferably carried out at room temperature. The analysis time can be determined according to the actual situation, and the complete analysis of the modified tea saponin shall prevail. In the post-processing process, the analytical agent needs to choose a pure solvent or a mixed solvent with good solubility for the tea saponin esterification product, for example, alcohol solvents or acetone and their aqueous solutions can be used, according to the tea saponin esterification product itself The characteristic of preferred resolving agent is one or more in ethanol aqueous solution, methanol aqueous solution or acetone aqueous solution, and ethanol aqueous solution, methanol aqueous solution, acetone aqueous solution all have higher affinity to polar group and non-polar group, As a further preference, the concentration of the solute in the described resolving agent is 50-95%; further preferably 70-90%, when the resolving agent of this concentration is selected, the resolving efficiency of the modified tea saponin is higher, simultaneously with the adoption of Compared with pure analytical agent, it reduces the cost of analytical agent and the pollution to the environment. The amount of resolving agent is generally 2-4 times the volume of the macroporous resin adsorbed with the esterification product of tea saponin, so as to facilitate the thorough analysis of the esterification product of tea saponin; in order to avoid waste of raw materials, as a further preference, the analysis The dosage of the agent is twice the volume of the macroporous resin adsorbed with the tea saponin esterification product, and when the resolution agent of this volume is selected, it can ensure that almost all the tea saponin esterification products are resolved. The decomposed macroporous resin can be recycled according to needs, further reducing the preparation cost.

In the post-treatment process, dilute hydrochloric acid, dilute sulfuric acid or acetic acid can generally be used to acidify the reaction liquid after the esterification reaction. The adjusted pH value is further preferably 4-5. When the pH value is 4-5, it can ensure that the unreacted lauric acid chloride is completely removed in the form of lauric acid, avoiding the waste of acidic reagents, and reducing waste liquid treatment. Difficulty, cost savings.

The present invention also provides a tea saponin laurate surfactant prepared by the above method. The surfactant is non-toxic and easy to degrade. Part or all of the hydroxyl groups are changed to ester groups, so that the tea saponin laurate surfactant of the present invention has the characteristics of nonionic surfactant and anionic surfactant, and overcomes the common carboxylate anionic surfactant in acidic conditions. For the defects of poor surface activity, the effect of foaming or defoaming can also be achieved by changing the pH value of the solution to meet the requirements of different industries.

Commercially available products can be used for the raw materials or reagents used in the present invention. The reaction process or post-treatment process can be carried out at room temperature unless otherwise specified.

Compared with the prior art, the present invention has the following advantages and effects:

(1) The tea saponin laurate surfactant of the present invention has better surface activity than tea saponin, and is suitable for the separation and extraction of scale removers and biofilm proteins and as emulsifiers.

(2) The tea saponin laurate surfactant of the present invention comes from natural raw materials, is non-toxic, and is easy to degrade.

(3) The preparation process of the present invention is simple, the reaction conditions are easy to control, and can be used in industrial production.

detailed description

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1

Add 1 mmol of tea saponin, 6 mmol of lauric acid chloride, and 12 mmol of anhydrous potassium carbonate to 10 ml of N,N-dimethylformamide, and stir and react at 25 degrees Celsius for 12 hours. After the reaction, add 10ml of water to the reaction solution for dilution, add 0.1N dilute hydrochloric acid, adjust the pH value of the reaction solution to 4-5, and use 10ml of petroleum ether and ethyl acetate mixed solvent (volume ratio: 1.5:2) to extract Three times to remove lauric acid; add AB-8 macroporous adsorption resin to absorb tea saponin laurate, the adsorption time is 5 hours, TLC detection until the adsorption is complete. Remove the adsorption liquid by suction filtration, add 2 times the volume of 80% ethanol aqueous solution to analyze the esterification product of tea saponin in the AB-8 type macroporous adsorption resin adsorbed with tea saponin laurate, and filter to remove the AB-8 after analysis. Type 8 macroporous adsorption resin, concentrated analytical solution by rotary evaporation, and then vacuum freeze-dried to obtain solid tea saponin laurate surfactant.

The infrared spectrum of the product shows that the absorption peak at 1750-1725cm ^-1 becomes stronger obviously, indicating that the C=O group is introduced, the absorption peak in the range of 1300-1000cm ^-1 is caused by the stretching vibration of the CO bond, and the absorption peak at 950-900cm ^-1 is The out-of-plane deformation vibration of -OH on the carboxyl group is formed. In summary, it can be preliminarily determined that the lauric acid group has been connected to the tea saponin molecule, and the product is a tea saponin laurate surfactant substituted by the lauric acid group.

Example 2

Add 1 mmol of tea saponin, 8 mmol of lauric acid chloride, and 16 mmol of anhydrous sodium carbonate into 10 ml of N,N-dimethylformamide, and stir and react at 25 degrees Celsius for 12 hours. After the reaction, add 10ml of water to the reaction solution for dilution, add 0.1N dilute hydrochloric acid, adjust the pH value of the reaction solution to 4-5, and use 10ml of petroleum ether and ethyl acetate mixed solvent (volume ratio: 1.5:2) to extract Three times to remove lauric acid; add AB-8 macroporous adsorption resin to absorb tea saponin laurate, the adsorption time is 5 hours, TLC detection until the adsorption is complete. Remove the adsorption solution by suction filtration, add 2 times the volume of 75% methanol aqueous solution to analyze the esterification product of tea saponin in the AB-8 type macroporous adsorption resin with tea saponin laurate, and filter to remove the AB-8 after analysis. Type 8 macroporous adsorption resin, concentrated analytical solution by rotary evaporation, and then vacuum freeze-dried to obtain solid tea saponin laurate surfactant. Infrared detection data are the same as in Example 1.

Example 3

1 mmol of tea saponin, 8 mmol of lauric acid chloride, and 15 mmol of sodium hydroxide were added to 10 ml of dimethyl sulfoxide, and stirred and reacted at 25 degrees Celsius for 12 hours. After the reaction, add 10ml of water to the reaction solution for dilution, add 0.1N dilute hydrochloric acid, adjust the pH value of the reaction solution to 4-5, and use 10ml of petroleum ether and ethyl acetate mixed solvent (volume ratio: 1.5:2) to extract Three times to remove lauric acid; add AB-8 macroporous adsorption resin to absorb tea saponin laurate, the adsorption time is 5 hours, TLC detection until the adsorption is complete. Remove the adsorption liquid by suction filtration, add 90% acetone aqueous solution of 2 times the volume to the AB-8 type macroporous adsorption resin adsorbed with tea saponin laurate to analyze the esterification product of tea saponin, and filter to remove the AB-8 after analysis. Type 8 macroporous adsorption resin, concentrated analytical solution by rotary evaporation, and then vacuum freeze-dried to obtain solid tea saponin laurate surfactant. Infrared detection data are the same as in Example 1.

Example 4

Add 1 mmol of tea saponin, 6 mmol of lauric acid chloride, and 12 mmol of anhydrous potassium carbonate to 10 ml of N,N-dimethylformamide, and stir and react at 25 degrees Celsius for 12 hours. After the reaction, add 10ml of water to the reaction solution for dilution, add 0.1N dilute hydrochloric acid, adjust the pH value of the reaction solution to 4-5, and use 10ml of petroleum ether and ethyl acetate mixed solvent (volume ratio: 1.5:2) to extract Three times to remove lauric acid; add AB-8 macroporous adsorption resin to absorb tea saponin laurate, the adsorption time is 5 hours, TLC detection until the adsorption is complete. Remove the adsorption solution by suction filtration, add 2 times the volume of 70% ethanol aqueous solution to analyze the esterification product of tea saponin in the AB-8 type macroporous adsorption resin with tea saponin laurate, and filter to remove the AB-8 after analysis. Type 8 macroporous adsorption resin, concentrated analytical solution by rotary evaporation, and then vacuum freeze-dried to obtain solid tea saponin laurate surfactant. Infrared detection data are the same as in Example 1.

Surface activity test:

The critical micelle concentration (cmc) of the tea saponin laurate surfactant target product prepared in Examples 1-4 was measured by the platinum plate method at 20°C, and the test results are shown in Table 1:

Table 1

Example Critical micelle concentration (cmc), unit: g/L 1 0.45 2 0.44 3 0.43 4 0.46

As can be seen from the test results in Table 1, the critical micelle concentration (cmc) of the tea saponin laurate surfactant prepared by the method of the present invention is about 0.45g/L, which is higher than that of the corresponding tea saponin (cmc=0.5g/L L) The activity is increased by 1.1 times, and it is suitable for the separation and extraction of detergents and biofilm proteins and as emulsifiers. At the same time, compared with the prior art, the preparation method of the present invention has simple process and mild process conditions, and is suitable for industrial production.

Claims (6)

1. a preparation method of tea saponin laurate surfactant, comprising: catalyzer, tea saponin and lauric acid chloride are added in the organic solvent, carry out esterification reaction, after reaction finishes, aftertreatment obtains tea saponin Lauric acid ester surfactant; described catalyst is one or more in potassium carbonate, sodium carbonate, sodium hydroxide; The molar ratio of described tea saponin, lauric acid chloride and catalyst is 1:1-20 : 1-20; the temperature of the esterification reaction is 20-30 degrees Celsius. 2. the preparation method of tea saponin laurate surfactant according to claim 1, is characterized in that, described aftertreatment method comprises: (1) The macroporous resin is added to the reaction system after the esterification reaction is completed, and the tea saponin laurate is absorbed by the macroporous resin. After the adsorption is completed, filter to obtain the macropores adsorbed with the tea saponin laurate resin; (2) dissolving the macroporous resin adsorbed with tea saponin laurate into a resolving agent, performing a resolving reaction, filtering, removing the solvent in the resolving solution, and obtaining a tea saponin laurate surfactant. 3. the preparation method of tea saponin laurate surfactant according to claim 2, is characterized in that, described resolving agent is one or more in ethanol aqueous solution, methanol aqueous solution, acetone aqueous solution. 4. the preparation method of tea saponin laurate surfactant according to claim 3 is characterized in that, the concentration of solute is 50-95% in the described resolving agent, and the consumption of described resolving agent is adsorption There are 2-4 times the volume of macroporous resin with tea saponin laurate. 5. the preparation method of tea saponin laurate surfactant according to claim 1, is characterized in that, described organic solvent is N,N-dimethylformamide, dimethyl sulfoxide, acetone one or more of . 6. A tea saponin laurate surfactant, characterized in that it is prepared by the preparation method of the tea saponin laurate surfactant described in any one of claims 1-5.