CN105688740B - Novel cation Anionic Gemini Surfactant and preparation method thereof - Google Patents

Abstract

The invention discloses a novel cationic twinning surfactant, the chemical name of which is 1,3-propylenediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate. The productive rate of the synthesized quaternary ammonium salt cationic surfactant of the present invention is higher, and the maximum after purification is 96.2%. The synthesis steps are simple and efficient, the reaction conditions are easier to control, and the product is easy to purify. Good performance, can be used in oil field development, household care products and other fields.

Description

Novel cationic twinned surfactant and preparation method thereof

technical field

The invention belongs to the field of preparation of surfactants in colloid and interface chemistry, and in particular relates to a preparation method of a new symmetrical geminiquaternary ammonium salt cationic surfactant.

Background technique

Gemini surfactants, also known as gemini surfactants, twin surfactants or dimeric surfactants, are composed of two or more amphiphilic molecules at or near their hydrophilic head groups. It is formed by connecting a linking group through a chemical bond. It is precisely because of the special structure of this type of surfactant that it has attracted extensive attention from researchers at home and abroad. Compared with single-chain surfactants, the special structure of two head groups connected by a linking group inhibits the head group separation during the orderly aggregation process, and can better promote its "monomer" in the interface or molecular aggregation. The close arrangement in the system makes the cmc value of the system 1-2 orders of magnitude lower than that of traditional surfactants, and shows a better synergistic effect when mixed with other surfactants. Therefore, twinned surfactants can be widely used in the preparation of New materials, fungicides, inhibition of metal corrosion, fabric dyeing and finishing, cosmetics research and development, and oil exploration and other fields.

This type of surfactant is usually expressed as m-s-m', where m, m' and s represent the number of carbon atoms on the hydrophobic chains on both sides and the linking group in the middle, respectively. If m=m', it is a symmetrical gemini surfactant; if m≠m', it is an asymmetric gemini surfactant. It is precisely because of the diversity of linkers and hydrophobic chains of gemini surfactants that the types of gemini surfactants are more abundant, which has attracted a large number of researchers to study and synthesize new gemini surfactants and use them in different fields. Anionic, cationic, nonionic, and amphoteric geminal surfactants have been synthesized. Among them, the cationic quaternary ammonium salt gemini surfactants have developed rapidly because of their superior physical and chemical properties, and most of the theoretical and applied studies have also focused on this. However, the synthesis, separation and purification of twinned surfactants are difficult and expensive. Most of the products are still in the stage of laboratory synthesis and have not been industrialized. This limits the use of such surfactants in the fields of industry and daily life. The promotion and use of surfactants also hinder researchers from conducting in-depth research and extensive exploration of this class of surfactants. There are two ways to solve the above problems: first, compound with ordinary surfactants, and find some systems with good synergistic effects, that is, very low interaction parameters (β); second, from the perspective of synthesis, use cheap raw materials and adopt environmentally friendly process route. Compared with the two, the former requires a large number of experiments to find the appropriate ratio, which is time-consuming and laborious; while the latter, as long as the synthesis conditions are mild, the raw materials are cheap and easy to obtain, and the synthesis process is simple and environmentally friendly, it will help twin surfactants in my country. promotion and application. Therefore, trying to synthesize gemini surfactants with different chain lengths and different linking groups, using readily available raw materials, and exploring simple synthetic routes can provide more samples for the research and application of this type of gemini surfactants, thereby promoting its research and application.

For most of the synthetic quaternary ammonium salt type gemini surfactants, the counter ion part is generally an inorganic anion, such as Cl ^- , Br ^- , because the cationic group is an active group, and people pay more attention to it. high. However, experimental studies have shown that counter ions not only affect the surface activity of surfactants, but also play a key role in some special properties, such as the ability to form intelligent aggregation structures and solution rheological properties. The practical application of salt surfactants is very important. For these reasons, it is of great significance to research and develop new varieties. After searching, the synthesis method of 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-dihalide has been studied, but the 1 , 3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-disalicylate-type gemini cationic surfactant synthesis and performance measurement have not been reported yet.

Contents of the invention

For existing problems, the object of the present invention is to provide about Gemini quaternary ammonium salt cationic surfactant 1,3-propanediamine N, N'-two (tetradecyl N, N' dimethyl)-dihydrate Preparation method of sylate.

The present invention uses tetradecyl dimethyl tertiary amine, hydrochloric acid, epichlorohydrin and sodium salicylate as raw materials, and uses a phase transfer method to synthesize the new geminal quaternary ammonium salt cationic surfactant. Using the previously synthesized 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl)-dihalide as the basic raw material, add to the raw material at a specific temperature and ratio Sodium salicylate, after mixing well, 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-disalicylate can be synthesized by gradual cooling method. The newly synthesized gemini surfactant has higher surface activity, adding a new member to the category of cationic gemini surfactants.

The scheme of the present invention is that the geminiquaternary ammonium salt type cationic surfactant has a chemical name of 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-disalicylic acid Salt, the structural formula is as follows:

.

The present invention also provides a preparation method of the geminiquaternary ammonium salt cationic surfactant, which is synthesized by a phase transfer method using tetradecyl dimethyl tertiary amine, hydrochloric acid, epichlorohydrin, and sodium salicylate as raw materials Geminiquat cationic surfactant.

Described preparation method, the steps are:

(1) Synthesis of 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-dichloride: Add n-propanol solvent and tetradecyl to a four-neck flask For alkyl dimethyl tertiary amine, add concentrated hydrochloric acid dropwise and stir evenly. After 5-6 minutes, continue to add n-propanol dropwise and cool with cold water until the reaction solution is transparent and colorless. The pH of the solution is nearly neutral when measured with pH test paper. After the white smoke in the bottle disappears, add epichlorohydrin dropwise, turn on the cooling water, heat the flask with an electric heating mantle and allow the solvent to reflux for 10 minutes, then add tetradecyl dimethyl tertiary amine dropwise (dropping time is 20 minutes) , then add n-propanol dropwise, control the temperature at 94-102°C, keep reflux, and use a voltage of 120 volts to react for 4-5 hours. When the reaction solution turns brown, stop heating, cool down, evaporate the solvent with a rotary evaporator, and transfer to a rotary evaporator Until the solvent is not dropped, a white viscous substance is obtained for purification, and the obtained product is transferred to a vacuum drying oven and dried for 24 hours to obtain 1,3-propanediamine N, N'-bis(tetradecyl N, N 'Dimethyl)-dichloride crude product.

(2) Synthesis of 1,3-propylenediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate: 1,3-propylenediamine N,N' -Transfer the crude product of bis(tetradecyl N,N'dimethyl)-dichloride to a four-necked flask, add absolute ethanol, stir to dissolve, then add sodium salicylate, stir, and at 75-85 In a warm water bath at ℃, the reaction was refluxed for 3-4 hours; after the reaction was completed, cool and stand still, filter the precipitate, take the supernatant and transfer it to a pear-shaped bottle, and evaporate the solvent with a rotary evaporator to obtain 1,3 - crude product of propylenediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate;

(3) Purification of 1,3-propanediamine N,N'-di(tetradecyl N,N'dimethyl)-disalicylate: the 1,3-propanediamine obtained in step (2) The crude product of amine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate was transferred to a four-necked flask, and ethyl acetate/acetone 5-10 times its volume was added Mix the solvent, heat and stir to reflux, keep the temperature at 85±2°C, a precipitate appears at the bottom of the mixed solution, filter the precipitate to take the supernatant, and then transfer it to a pear-shaped bottle, evaporate the ethyl acetate/acetone mixed solvent with a rotary evaporator, A white solid was obtained, and the obtained white solid was re-solventized, recrystallized, and dried under vacuum to obtain the pure product 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-di Salicylates.

In the preparation method of the novel cationic twinned surfactant, the step (1) tetradecyl dimethyl tertiary amine: epichlorohydrin: hydrochloric acid is 0.10: 0.04: 0.04-0.05 in molar ratio (preferably, Tetradecyl dimethyl tertiary amine: epichlorohydrin: hydrochloric acid is 0.10: 0.04: 0.045 in molar ratio).

In the preparation method of the novel cationic twinned surfactant, step (1) controls the temperature at 96-100°C (preferably, controls the temperature at 98°C).

In the preparation method of the novel cationic twinned surfactant, step (1) purification treatment operation is the purification treatment operation is to transfer the white viscous substance to another three-necked flask, add acetone, and heat to reflux for 5-15 minutes , first carry out hot suction filtration, wait for the filtrate to cool and precipitate a white solid, then carry out cold suction filtration, then recrystallize again, and finally add acetone to a pear-shaped bottle filled with white viscous objects through vacuum suction filtration, and let it stand for 12 hours, then transfer the liquid to a four-necked flask, heat to boiling, and perform hot filtration, transfer the mother liquor to a beaker, cool to room temperature, obtain a white solid precipitate, and then filter under reduced pressure.

The preparation method of the novel cationic twinned surfactant, step (2) 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-dichloride: water Sodium sylate is 1:2.0-2.1 in molar ratio.

In the preparation method of the novel cationic twinned surfactant, step (2) the temperature of the warm water bath is 77-83°C (preferably, the temperature of the warm water bath is 80°C).

In the preparation method of the novel cationic twinned surfactant, step (3) the ratio of ethyl acetate to acetone in the ethyl acetate/acetone mixed solvent is 2:1.

In the preparation method of the novel cationic twinned surfactant, the solvent added in step (3) is one of acetone or ethyl acetate/ethanol mixed solution.

In the preparation method of the novel cationic twinned surfactant, the amount of solvent added in step (3) is 4-8 times the volume of the white solid (preferably, the amount of solvent added is 6 times the volume of the white solid).

The invention discloses the preparation of a novel quaternary ammonium salt gemini cationic surfactant 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl)-disalicylate method. Its synthetic route is to react tetradecyl dimethyl tertiary amine and epichlorohydrin under the condition of neutral pH value and n-propanol as solvent at 98°C±1°C for 4h-5h to obtain 1 , 3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-dichloride; then 1,3-propanediamine N, N'-bis( Tetradecyl N, N'dimethyl)-dichloride was dissolved, added sodium salicylate, reacted in a water bath at 80°C±2°C for 3-4h, filtered the precipitate, mixed with ethyl acetate and absolute ethanol Solvent (volume ratio 2:1) to recrystallize the supernatant to obtain 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-disalicylic acid Salt. The method of the invention has simple and convenient steps, easy control of the reaction conditions, high yield of the target geminiquaternary ammonium salt cationic surfactant, and easy purification of the product.

The advantages that the present invention has are as follows:

1. Use common and easy-to-buy tetradecyldimethyl tertiary amine and cheap epichlorohydrin and concentrated hydrochloric acid as raw materials, first synthesize the geminal quaternary ammonium salt cationic surfactant whose counter ion is chlorine, and then use the The activator reacts with sodium salicylate in a molar ratio of 1:1 to obtain a new type of geminiquaternary ammonium salt cationic surfactant whose counterion is salicylate. Since the structure of salicylate itself is easy to form hydrogen bonds, it can improve The surface activity of surfactants. The specific surface activity parameters are shown in Table 2. For convenience of comparison, the surface activity data of 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-dichloride is also listed together.

2. The productive rate of the synthesized quaternary ammonium salt cationic surfactant of the present invention is higher, and the highest is 96.2% after purification.

3. The synthesis steps of the present invention are simple and efficient, and the reaction conditions are easier to control.

4. The product is easy to purify.

5. The raw materials of the quaternary ammonium salt type geminal cationic surfactant studied in the present invention are cheap and easy to get, and the synthetic route is simple and efficient. Because the linking group of the surfactant contains a hydroxyl group, in the aqueous solution, the hydroxyl group can form hydrogen bonds among each other and with water molecules, so that the distance between the ion head groups of the hydroxyl-containing molecules is closer, thereby improving the Dispersion of surfactants. In addition, the active agent can also form worm-like micelles, so it can be used in oil field development, household care products and other fields.

detailed description

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

Used raw material and reagent of the present invention:

tetradecyl dimethyl tertiary amine (CP); epichlorohydrin (AR); hydrochloric acid (AR); n-propanol (AR); ethyl acetate (AR); acetone (AR); absolute ethanol (AR ).

The synthetic route is as follows:

(1)

(2)

(3)

Example 1

1,3-propanediamine N, the preparation method of N'-two (tetradecyl N, N' dimethyl) disalicylate, comprises the steps:

(1) Synthesis of 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl) dichloride

Add 20ml of n-propanol and 0.04mol (9.64g, about 13.1ml) tetradecyldimethyl tertiary amine into a 250ml four-neck flask, stir well, then add 0.045mol (about 3.8ml) of concentrated hydrochloric acid dropwise, stir well, After 5-6 minutes, after the white smoke disappears, add 20ml of n-propanol dropwise and stir, and cool with cold water until the solution is transparent and colorless. The pH value of the solution is about 6 as measured by pH test paper, and 0.04mol (about 3.2ml ) of epichlorohydrin, heated the flask with an electric heating mantle until the reaction solution refluxed, and then added 0.06mol (about 19.75ml) of excess tetradecyldimethyl tertiary amine dropwise after 10 minutes of reaction. Note that it should be within 20 minutes After the dropwise addition, add 10ml of n-propanol dropwise. In order to keep the reaction solution reflux, control the heating temperature at 98°C, keep the heating voltage at about 120V, and react for 4.5 hours until the reaction solution has a tea color and the temperature rises to nearly 100°C. , stop heating. Use a rotary evaporator to rotary evaporate the solvent in the reaction solution, and recover n-propanol to obtain a white viscous solid. Continue rotary evaporation until foaming occurs and the solvent no longer evaporates. Note that the voltage should not be too high during rotary evaporation.

Then add 60ml of acetone to the pear-shaped bottle filled with white viscous solid, let it stand for 12 hours, then transfer the liquid to a four-necked bottle, heat it to boiling, carry out hot filtration, transfer the mother liquor to a beaker, and cool to room temperature , a white solid precipitate was obtained, and the colorless crude product 14-3(OH)-14(2Cl) was obtained after suction filtration under reduced pressure, and 20.82 g of the product was obtained, and the yield was 90.5%.

(2) Synthesis of 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl) disalicylate

Transfer 20.82g of the above synthesis to a 500ml four-necked bottle, add 100ml of absolute ethanol, heat and stir to dissolve, and then follow the 1,3-propanediamine N,N'-bis(tetradecyl N,N Add sodium salicylate (about 11.59g) in a molar ratio of dimethyl)-dichloride to sodium salicylate at a ratio of 1:2, and keep the temperature in a warm water bath at 80°C and stir the solution to allow it to reflux for 3.5 After the reaction is completed, move the solution to a pear-shaped bottle, let it stand for 1 hour, filter the precipitate, take the supernatant and evaporate the absolute ethanol with a rotary evaporator to obtain 1,3- Crude product of propylenediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate.

(3) Purification of 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)disalicylate

Transfer the crude product of 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate obtained above to a four-neck flask, and add its volume of 7.5 double the ethyl acetate/acetone mixture (volume ratio of ethyl acetate/acetone is 2:1), heat and stir, keep the temperature at (85±2)°C, reflux the solution, and precipitate appears at the bottom of the mixed solution, filter the precipitate Take the supernatant, transfer it to a pear-shaped bottle, and evaporate the ethyl acetate/acetone mixed solvent with a rotary evaporator to obtain a white solid, which is mixed with ethyl acetate/absolute ethanol 6 times its volume solution (ethyl acetate/dehydrated ethanol volume ratio is 2:1), recrystallized 3-4 times, and the product was vacuum-dried to obtain 20.02 g of pure 14-3(OH)-14(2Sal).

Example 2

1,3-propanediamine N, the preparation method of N'-two (tetradecyl N, N' dimethyl) disalicylate, comprises the steps:

(1) Synthesis of 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl) dichloride

Add 25mL of n-propanol and 0.04mol (about 13.5mL) tetradecyldimethyl tertiary amine to a 250mL four-necked bottle, stir with an electromagnetic stirrer (the speed should not be too fast), and drop 0.045mol of concentrated hydrochloric acid (about 3.8 ml) white smoke appears, after 5-6 minutes, add 25mL n-propanol dropwise with a separatory funnel, and cool with cold water until the reaction solution is transparent and colorless, and its pH value is nearly neutral (pH value is about 6 or 7) , after the white smoke in the bottle disappears, add 0.04mol (about 3.1mL) epichlorohydrin dropwise, install a condenser, heat the solution with an electric heating mantle to make it reflux, and after 10 minutes, add tetradecyldimethyl Tertiary amine 0.06mol (about 20mL, add dropwise in about 20 minutes), then add dropwise 10mL of n-propanol, control the temperature (98±1)°C, voltage 120V, reaction time 4.5 hours, the reaction solution is brown, stop heating immediately , the solution was slightly cooled, and the n-propanol was rotated to evaporate until the solvent was not dropped by the rotary evaporator. At this time, more white viscous substances appeared. Transfer the white viscous substance to another three-necked flask, add 60mL of acetone, heat and reflux for 10 minutes, and perform hot suction filtration. After the filtrate cools and precipitates a white solid, perform cold suction filtration, and then recrystallize 3 times. After vacuum filtration, the white solid was 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-dichloride, with a yield of 90.7%. The product was transferred to a vacuum oven and dried for 24 hours.

(2) Synthesis of 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl)-disalicylate

Transfer the dried 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-dichloride to a four-neck flask, add absolute ethanol, stir to dissolve, and follow the Add sodium salicylate to 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-dichloride and sodium salicylate molar ratio of 1:2, stir , and in a warm water bath at (80±2)°C, react for 3.5 hours; after the reaction, cool and stand still, filter the precipitate, obtain the supernatant and transfer it to a pear-shaped bottle, evaporate the solvent with a rotary evaporator and recover , to obtain the crude product of 1,3-propanediamine N,N'-bis(tetradecyl N,N'dimethyl)-disalicylate;

(3) Purification of 1,3-propanediamine N, N'-di(tetradecyl N, N'dimethyl)-disalicylate

Transfer the crude product of 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl)-disalicylate obtained in step (2) to a four-necked flask, and add its 7.5 times the volume of ethyl acetate/acetone mixed solvent (ratio: 2:1), continue to heat, stir and reflux, keep the temperature at (85±2)°C, obtain a mixed solution containing a small amount of precipitate, filter and remove the obtained supernatant The solution was transferred to a pear-shaped bottle, and the ethyl acetate/acetone mixed solvent was continuously evaporated with a rotary evaporator to obtain a white solid, which was added with acetone 6 times its volume, stirred evenly, and recrystallized again. After drying, pure 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl) disalicylate is obtained.

The obtained product was subjected to elemental analysis and ¹ H NMR spectrum determination. The results are shown in Table 1

Table 1. NMR and elemental analysis data of 14-3(OH)-14(2Sal)

Table 2: Comparison of some surface activity parameters (for convenience of comparison, 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl) dichloride is abbreviated as 14-3( OH)-14(2Cl), 1,3-propanediamine N, N'-bis(tetradecyl N, N'dimethyl) disalicylate is abbreviated as 14-3(OH)-14( 2Sal).

Table 2. Surface activity parameters (25 ^o C)

cmc ¹ is measured by conductometric method and cmc ² is measured by surface tension method.

It can be seen from Tables 1 and 2 that compared with 14-3(OH)-14(2Cl) whose counterion is chlorine, the surface activity of the newly synthesized surfactant is improved by nearly 1% due to the introduction of organic counterion salicylate. Order of magnitude, that is, cmc is reduced from 0.316 mmol·L ^-1 to 0.0475 or 0.0482 mmol·L ^-1 . The melting point of the compound decreased from 87-88°C to 83-84°C. The surface tension γcmc decreased to 39.32 mN·mL ^-1 at the critical micelle concentration. The saturated adsorption capacity also increases about 1.6 times.

Finally, it should be noted that the embodiments are only the best specific implementation of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it is still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

This invention was funded by the National Natural Science Foundation of China (No: 21473084, 21073081), the Key Research Fund of Liaocheng University (318011402), and the key teaching and research project (311161518).

Claims (9)

1. the preparation method of cation Anionic Gemini Surfactant, it is characterised in that step is：

（1）1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）The synthesis of-dichloride：Into four-hole boiling flask, add Normal propyl alcohol solvent and dodecyldimethylamine base tertiary amine, are added dropwise concentrated hydrochloric acid, stir, after 5-6 minutes, continue that normal propyl alcohol is added dropwise, Cold water is cooled down, until reaction solution clear, colorless, solution acid alkalinity weakly acidic pH is measured with pH test paper, treats that white smoke disappears in bottle Afterwards, epoxychloropropane is added dropwise, cooling water is connected, when heating flask by solvent refluxing 10 minutes with electric jacket, myristyl is added dropwise Dimethyl tertiary amine, then normal propyl alcohol is added dropwise, 94-102 DEG C of temperature is controlled, is maintained the reflux for, 120 volts of voltage, is reacted 4-5 hours, treats anti- Answer liquid in dark brown, stop heating, cooling uses Rotary Evaporators evaporation solvent, untill Rotary Evaporators do not drip solvent, obtains white Color sticky mass does purification process, and products therefrom is transferred to vacuum drying chamber, dries 24 hours, that is, obtains 1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）- dichloride crude product；

（2）1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）The synthesis of-two salicylates：By 1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）- dichloride crude product is transferred in four-hole bottle, addition absolute ethyl alcohol, stirring and dissolving, Sodium salicylate is added, is stirred, and in 75-85 DEG C of tepidarium, reaction backflow 3-4 hours；After completion of the reaction, cool down quiet Put, precipitation is filtered, take supernatant and move in pears type bottle, solvent is evaporated with Rotary Evaporators, that is, obtains 1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）The crude product of-two salicylates；

（3）1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）The purifying of-two salicylates：By step（2）Gained 1, 3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）The crude product of-two salicylates is transferred in four-hole bottle, adds its body Ethyl acetate/acetone mixed solvent of 5-10 times of accumulated amount, heating stirring backflow, temperature is maintained at 85 ± 2 DEG C, mixed solution bottom Precipitate, filter the precipitation and take supernatant, transfer in pears type bottle, it is mixed with Rotary Evaporators evaporation of acetic acid ethyl ester/acetone Bonding solvent, obtains white solid, and gained white solid solubilizer again, recrystallization is vacuum dried, produces sterling 1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）- two salicylates；Chemical name is 1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）- two salicylates, structural formula is as follows：

。

2. preparation method as claimed in claim 1, it is characterised in that step（1）Dodecyldimethylamine base tertiary amine: epoxy chloropropionate Alkane: concentrated hydrochloric acid is using molar ratio computing as 0.10: 0.04：0.04-0.05.

3. preparation method as claimed in claim 1, it is characterised in that step（1）It is 96-100 DEG C to control temperature.

4. preparation method as claimed in claim 1, it is characterised in that step（1）Purification process operation is by thick white shape Material is transferred to another three-necked flask, adds acetone, is heated to reflux after 5-15 minutes, first carries out hot suction filtration, treats filtrate cooling analysis Go out white solid, then carry out cold suction filtration, then recrystallize again, most afterwards through depressurizing suction filtration or to the pears for filling thick white object Acetone is added in shape bottle, 12 hours are stood, then liquid is transferred in four-hole bottle, boiling is heated to, heat filtering is carried out, mother liquor is turned Move on in beaker, be cooled to room temperature, obtain white solid precipitation, then depressurize suction filtration.

5. preparation method as claimed in claim 1, it is characterised in that step（2）1,3- propane diamine N, N '-two（Myristyl N, N ' dimethyl）- dichloride: sodium salicylate is using molar ratio computing as 1: 2-2.1.

6. preparation method as claimed in claim 1, it is characterised in that step（2）Warm water bath temperature is 77-83 DEG C.

7. preparation method as claimed in claim 1, it is characterised in that step（3）Acetic acid in ethyl acetate/acetone mixed solvent Ethyl ester is 2 with acetone ratio:1.

8. preparation method as claimed in claim 1, it is characterised in that step（3）The solvent of addition be acetone or ethyl acetate/ One kind in absolute ethyl alcohol mixed liquor.

9. preparation method as claimed in claim 1, it is characterised in that step（3）The amount for adding solvent is white solid volume 4-8 times of amount.