CN102319550B - Low-concentration viscoelastic surfactant solution and preparation method thereof - Google Patents

Abstract

The invention relates to a preparation method of a low-concentration viscoelastic surfactant solution. The structure of an active ingredient is shown in the specifications. The preparation method of the surfactant solution comprises the following steps of: synthesizing an oleic acid-based Gemini quaternary ammonium salt surfactant in the ratio 18:(1-2)-18:1; performing ion exchange; neutralizing with acid and alkali; and compounding. The surfactant solution is characterized in that: the surfactant solution shows higher viscoelasticity at an extremely low concentration, and can be applied to oil field fracturing fluids, drag reduction agents and daily detergent formulas. The invention contributes to facilitating the application of oleic acid to a surfactant viscoelastic system.

Description

A kind of low concentration viscoelastic surfactant solution and preparation method thereof

technical field

The invention relates to a viscoelastic surfactant solution, in particular to a low-concentration viscoelastic surfactant solution using natural product oleic acid as a raw material and a preparation method thereof.

Background technique

Surfactant viscoelastic solutions are widely used in daily life and industrial production, such as fracturing fluid for oil recovery in oil fields, drag reducer and daily cleaning agent formulations, etc. A common surfactant viscoelastic solution can be obtained by adding a large amount of inorganic or organic salts to a single-headed, single-tailed surfactant solution. This kind of system usually requires a high concentration of surfactant, which increases the cost on the one hand, and causes unnecessary pollution to the system on the other hand, increasing the difficulty of post-processing.

The viscoelasticity of the surfactant solution is related to the molecular structure of the surfactant, the type and concentration of the counter ion, and so on. Gemini surfactants can exhibit strong viscoelasticity at lower concentrations, which has aroused widespread interest (Zana, R. Adv. Colloid Interface Sci. 2002, 97, 205-253). Using the molecular skeleton of Gemini, and by adjusting the type and length of the hydrophobic chain and the type and ratio of counter ions, it is expected to obtain molecular species with better viscoelasticity.

Oleic acid exists widely in nature in the form of glyceride and is easy to obtain. After separating and purifying oleic acid from natural products, oleyl alcohol can be obtained through transesterification, esterification and reduction. After oleyl alcohol is halogenated, it can be widely used in the preparation process of surfactants.

Contents of the invention

In order to solve the problem that a large amount of salt needs to be added to the solution in the prior art, the concentration of the surfactant is relatively high, and the post-treatment is difficult, the invention provides a method for preparing a low-concentration viscoelastic surfactant solution. Based on the Gemini surfactant prepared with oleyl alcohol, the surfactant solution obtained after compounding has high viscoelasticity at a very low concentration.

The technical scheme of the present invention is: a low-concentration viscoelastic surfactant solution, which is obtained by compounding active ingredients of surfactants and inorganic salts, wherein the active ingredients of surfactants are oleic acid-based Gemini quaternary ammonium salt surface active Agent 18:1-2-18:1·2NO ₃ , the structural formula is as follows:

The inorganic salt is sodium nitrate, and the molar ratio of the active ingredient of the surfactant to the sodium nitrate is 1:1-5.

A kind of preparation method of described viscoelastic surfactant solution, firstly prepare Gemini surfactant, then process with strong basic ion exchange resin to obtain corresponding quaternary ammonium base, then obtain surfactant through acid-base neutralization The active ingredient is finally compounded with an inorganic salt to obtain the viscoelastic surfactant; wherein, the inorganic salt is sodium nitrate, and the Gemini surfactant is an oleic acid-based Gemini surfactant 18:1-2 -18:1 is obtained by the following reaction:

The solvent is any one of ethanol, isopropanol, acetonitrile, acetone, etc. or any number of mixed solvents in any proportion.

The acid used in acid-base neutralization is nitric acid.

The molar ratio of oleyl alcohol to p-toluenesulfonyl chloride is 1:1 to 3, and the reaction temperature is -20°C to -5°C.

The p-toluenesulfonyl chloride is first dissolved in methylene chloride and then reacted with oleyl alcohol.

The molar ratio of p-toluenesulfonate of oleyl alcohol to lithium bromide is 1:1-5, and the reaction temperature is room temperature.

While adding lithium bromide, anhydrous acetone was added as a reaction solvent.

Beneficial effect:

The obtained surfactant viscoelastic solution has better viscoelasticity at 1.7wt% when the active ingredient concentration of the surfactant is lower, which can significantly reduce the use cost.

Description of drawings

Figure 1 Dynamic shear diagram of surfactant viscoelastic solution (0.023mol/L, G’(●), G”(○)).

Fig. 2 Steady-state shear diagram of surfactant viscoelastic solution (0.023mol/L, 1.7wt%).

Detailed ways

A low-concentration viscoelastic surfactant solution is obtained by compounding active ingredients of surfactants and inorganic salts, and the structural formula of the active ingredients is as follows:

为油酸基Gemini季铵盐表面活性剂18∶1-2-18∶1·2NO₃，所述的无机盐为硝酸钠，表面活性剂有效成分与硝酸钠的摩尔比为1∶1～5。

It is an oleic acid-based Gemini quaternary ammonium salt surfactant 18:1-2-18:1·2NO ₃ , the inorganic salt is sodium nitrate, and the molar ratio of the active ingredient of the surfactant to sodium nitrate is 1:1-5 .

A method for preparing a low-concentration viscoelastic surfactant solution, first preparing a Gemini surfactant, then treating it with a strong basic ion exchange resin to obtain the corresponding quaternary ammonium base, and then obtaining the surfactant through acid-base neutralization The active ingredient is finally compounded with an inorganic salt to obtain the viscoelastic surfactant; wherein, the inorganic salt is sodium nitrate, and the Gemini surfactant is an oleic acid-based Gemini surfactant 18:1-2 -18:1 is obtained by the following reaction:

Among them, oleyl alcohol can be directly purchased from the market, or can be prepared from natural product oleic acid through esterification and reduction. The preparation reaction formula is as follows:

In the alcohol bromination step, oleyl alcohol is first reacted with p-toluenesulfonyl chloride, and then reacted with anhydrous lithium bromide. The molar ratio of oleyl alcohol to p-toluenesulfonyl chloride is 1:1-3, and the molar ratio of anhydrous lithium bromide is 1:1-5.

In the quaternization step, the molar ratio of N,N,N',N'-tetramethylethylenediamine to 1-bromo-cis-9-octadecene is 1:2-5. The solvent is any one of ethanol, isopropanol, acetonitrile, acetone, n-butanol, N,N-dimethylformamide or several mixed solvents in any proportion, and the reaction time is 24 to 120 at 80-100°C Hour.

Taking oleic acid as a starting material to prepare the low-concentration viscoelastic surfactant solution, the specific reaction can be as follows:

Esterification of oleic acid:

Mix oleic acid and 10 times the mole number of methanol, and reflux at 80-90°C for 5-8 hours under the catalysis of concentrated sulfuric acid. After removing methanol, washing with water and drying, distilled under reduced pressure to obtain methyl oleate.

Reduction of methyl oleate to oleyl alcohol:

Methyl oleate was reacted with an equimolar amount of lithium aluminum hydride in anhydrous tetrahydrofuran at -15 to 0°C for 3 to 10 hours. After post-processing and drying, oleyl alcohol is obtained. The described lithium aluminum hydride can also be a reductant that does not reduce the double bond, such as red aluminum, but only reduces the ester group.

Bromination of oleyl alcohol:

The molar ratio of oleyl alcohol to p-toluenesulfonyl chloride is 1:1-3, in the presence of 2-10 times the molar amount of triethylamine, react at -20-5°C for 2-15 hours. After washing with water and drying, the p-toluenesulfonate of oleyl alcohol is obtained. The molar ratio of p-toluenesulfonate to anhydrous lithium bromide is 1:1-5, and the reaction is carried out at room temperature for 2-50 hours. After filtration, solvent removal and column chromatography, 1-bromo-cis-9-octadecene was obtained.

Quaternization:

The molar ratio of N,N,N',N'-tetramethylethylenediamine to 1-bromo-cis-9-octadecene is 1:2~5, use ethanol as solvent, and reflux at 90°C for 96 hours . After cooling, the solvent was evaporated, recrystallized three times with ethanol-ethyl acetate, and vacuum-dried to obtain the product oleic acid-based Gemini surfactant 18:1-2-18:1. The solvent is any one of ethanol, isopropanol, acetonitrile, acetone, etc. or any number of mixed solvents in any proportion.

Ion exchange:

The strongly basic ion exchange resin is processed by acid immersion-water washing-sodium hydroxide solution washing-water washing-acid washing-water washing-sodium hydroxide solution washing-water washing. 3 g of oleic acid-based Gemini surfactant 18:1-2-18:1 was dissolved in 20 mL of distilled water, added to an ion exchange column, and eluted with distilled water at a flow rate of 5 mL/min. Tested with phenolphthalein test solution, began to collect when the effluent turned phenolphthalein red, and obtained quaternary ammonium alkali solution of oleic acid-based Gemini surfactant 18:1-2-18:1.

Acid-base neutralization and compounding:

Prepare a certain concentration of nitric acid solution, and use potentiometric titration to determine the exact concentration of quaternary ammonium base and nitric acid solution. The acid and alkali are neutralized according to the molar ratio of 1:1, and then compounded with a certain proportion of sodium nitrate to obtain the surfactant viscoelastic solution.

Example 1

(1) Synthesis of methyl oleate

Add oleic acid (120 g), anhydrous methanol (120 g) and concentrated sulfuric acid (1 g) into a 500 mL single-necked bottle, and stir and reflux at 82° C. for 6 hours. After cooling, the low boiling point substances were removed, and the organic layer was washed with dilute sodium bicarbonate solution until neutral. Add anhydrous magnesium sulfate and dry overnight. After filtration, the crude product was distilled under reduced pressure to obtain methyl oleate. 176～178℃/6mmHg(uncorrected) Yield: 90.0%

¹ H NMR (300 MHz, CDCl ₃ , Me ₄ Si) δ (ppm): 5.35 (m, 2H, CH=CH), 3.66 (s, 3H, OCH ₃ ), 2.30 (t, 2H, CH ₂ COOCH ₃ ) , 2.02(t, 4H, CH ₂ CH=CHCH ₂ ), 1.62(t, 2H, CH ₂ CH ₂ COOCH ₃ ), 1.30～1.27(m, 20H, CH ₃ (CH ₂ ) ₆ CH ₂ CH=CHCH ₂ (CH ₂ ) ₄ ), 0.88(t, 3H, CH ₃ )

(2) Synthesis of oleyl alcohol

Add methyl oleate (52 g) and tetrahydrofuran (207 g) after sodium-benzophenone reflux to remove water into a 500 mL single-necked bottle. Put the single-necked bottle into a low-temperature reactor, and control the temperature below -10°C. Lithium aluminum hydride (8 g) was added slowly and more gas evolution began. Stir for half an hour after the addition, and then transfer to room temperature to continue the reaction for 4 hours. The mixture was cooled to -15°C, firstly mixed, and 8mL of water was slowly added thereto, and then 8mL of 10%wt sodium hydroxide solution was added. After the addition, stir at room temperature for half an hour, and filter with suction to obtain a clear filtrate. Dry the filtrate with anhydrous magnesium sulfate, filter and remove the solvent under reduced pressure to obtain the product oleyl alcohol. Yield: 86.3%

¹ H NMR (400 MHz, CDCl ₃ , Me ₄ Si) δ (ppm): 5.34 (t, 2H, CH=CH), 3.63 (t, 2H, CH ₂ OH), 2.00 (d, 4H, CH ₂ CH= CHCH ₂ ), 1.85 (s, 1H, OH), 1.58～1.21 (m, 24H, CH ₃ (CH ₂ ) ₆ CH ₂ CH=CHCH ₂ (CH ₂ ) ₆ ), 0.88 (t, 3H, CH ₃ )

(3) Synthesis of 1-bromo-cis-9-octadecene:

Add oleyl alcohol (70.4 g, 0.26 mol), triethylamine (53 g, 0.52 mol) and 100 mL of dichloromethane into a 500 mL three-necked flask, and cool to -10°C. While stirring, a dichloromethane solution of p-toluenesulfonyl chloride (65 g, 0.34 mol) was slowly added dropwise, during which white turbidity occurred. After the addition was complete, it was stirred at room temperature for 5 hours. The reaction solution was first washed with dilute hydrochloric acid solution, and then washed with distilled water until neutral. Dry with anhydrous magnesium sulfate, and filter with suction to obtain a light yellow filtrate; remove the solvent to obtain a dark yellow liquid. The liquid was transferred to a 500 mL single-necked bottle, and 300 mL of anhydrous acetone and anhydrous lithium bromide (35 g, 0.4 mol) were added at the same time, and stirred at room temperature for 32 hours. Evaporate acetone to dryness, add 200 mL of petroleum ether, and let stand at -5°C for 4 hours. The precipitate was filtered to obtain a clear filtrate, and the solvent was evaporated to obtain the initial product. The primary product was purified by silica gel column chromatography, and the eluent was petroleum ether. The final product is a colorless transparent liquid. Yield: 51.2%.

¹ H NMR (300 MHz, CDCl ₃ ) δ5.35 (d, 2H, CH=CH), 3.39 (t, 2H, CH ₂ Br), 2.01 (d, 4H, CH ₂ CH=CHCH ₂ ), 1.90～1.77 (m, 2H, CH ₂ CH ₂ Br), 1.35 (m, 22H, CH ₃ (CH ₂ ) ₆ CH ₂ CH=CHCH ₂ (CH ₂ ) ₆ ), 0.88 (t, 3H, CH ₃ ).

(4) Synthesis of oleic acid-based Gemini surfactant 18:1-2-18:1

Add 1-bromo-cis-9-octadecene (44 g, 0.13 mol), tetramethylethylenediamine (7 g, 0.06 mol) and 200 mL of ethanol into a 500 mL single-necked bottle and reflux for 96 hours. After cooling, the solvent was distilled off, recrystallized three times with ethanol-ethyl acetate, and dried in vacuo to obtain the product as a white waxy solid. Yield: 25.1%.

¹ H NMR (300MHz, CDCl ₃ ) δ5.34(s, 4H), 4.76(s, 4H), 3.71(s, 4H), 3.52(s, 12H), 2.01(m, 8H), 1.82(m, 4H), 1.37～1.27(m, 44H), 0.88(t, 6H).

(5) Preparation of quaternary ammonium base

Treatment of strong basic ion exchange resin: Soak 400g of 717-type anion-exchange resin (chlorine type) in dilute hydrochloric acid solution for two days, put it into the column, and wash it with distilled water until neutral. Use 1mol/L sodium hydroxide solution for the first exchange, with a flow rate of 10mL/min, until the silver nitrate solution acidified with nitric acid is tested for no precipitation. After washing with distilled water until neutral, exchange it with 1mol/L hydrochloric acid solution at a flow rate of 20mL/min, and then wash with distilled water until neutral. Finally, exchange with 1.5mol/L sodium hydroxide solution at a flow rate of 10mL/min until the silver nitrate solution acidified with nitric acid has no precipitation. Wash with distilled water until neutral, and the treatment is complete.

3 g of oleic acid-based Gemini surfactant 18:1-2-18:1 was dissolved in 100 mL of distilled water, added to an ion exchange column, and eluted with distilled water at a flow rate of 5 mL/min. Test with phenolphthalein test solution, collect when the effluent turns phenolphthalein red, and obtain a quaternary ammonium alkali solution of 18:1-2-18:1.

(6) Acid-base neutralization and compounding

Prepare a certain concentration of nitric acid solution, and use sodium carbonate standard solution to calibrate the exact concentration. The exact concentration of the quaternary ammonium alkali solution is calibrated with a standard solution of potassium hydrogen phthalate. Take a certain volume of nitric acid solution and quaternary ammonium alkali solution and dilute with distilled water respectively, mix according to the ratio of acid-base neutralization 1:1, the concentration of the active ingredient of the viscoelastic surfactant obtained at last is 0.023mol/L (1.7wt%) . After weighing 3 times the amount of solid sodium nitrate (0.6wt%) into the solution and dissolving, the low-concentration viscoelastic surfactant solution is obtained.

(7) The resulting solution is subjected to dynamic and steady-state rheological measurements at room temperature to obtain relevant data. The specific data are shown in Fig. 1 and Fig. 2. As can be seen from Fig. 1, the solution shows obvious viscoelastic properties, showing Characteristics of Maxwell fluids. It can be seen from Figure 2 that the zero-shear viscosity of the solution can reach 7.4 Pa·s, which is much higher than the viscosity of common surfactant solutions at similar concentrations.

The contrast of table 1 embodiment and common CTAB-inorganic salt system

Control system r: Candau, S.J., Hirsch, E., Zana, R., Delsanti, M.Langmuir 1989, 5, 1225.

It can be clearly seen from the above table that the system of the present invention can have very good zero-shear viscosity at a very low concentration, and the amount of inorganic salt is also very low.

Example 2

Synthesis of 1-bromo-cis-9-octadecene:

Using commercially available oleyl alcohol, take 50g oleyl alcohol and 36g p-toluenesulfonyl chloride, the molar ratio of the two is 1:1, and react at -20°C for 15 hours in the presence of 10 times the molar amount of triethylamine. After washing with water and drying, the p-toluenesulfonate of oleyl alcohol is obtained. 80 g of anhydrous lithium bromide was added in a 5-fold molar amount, and acetone was added at the same time, and the reaction was carried out at room temperature for 2 hours. Acetone was evaporated to dryness, petroleum ether was added, and after standing at -5°C, 1-bromo-cis-9-octadecene was obtained by filtration, solvent removal, and column chromatography with a yield of 21.5%.

Quaternization:

1-Bromo-cis-9-octadecene (40g, 0.12mol), N,N,N',N'-tetramethylethylenediamine (5g, 0.04mol), the molar ratio of the two is 3: 1. Add 150mL of anhydrous acetonitrile into a 500mL single-necked bottle and reflux for 100 hours. After cooling, the solvent was distilled off, recrystallized three times with ethanol-ethyl acetate, and dried in vacuo to obtain the product as a white waxy solid. Yield: 38.5%.

Example 3

Synthesis of 1-bromo-cis-9-octadecene:

Add oleyl alcohol (50 g, 0.186 mol), triethylamine (56 g, 0.56 mol) and 220 mL of dichloromethane into a 500 mL three-necked flask, and cool to -10°C. Under stirring, a dichloromethane solution of p-toluenesulfonyl chloride (71 g, 0.37 mol) was slowly added dropwise. The molar ratio of oleyl alcohol to p-toluenesulfonyl chloride was 1:2, and white turbidity occurred during the dropping process. Stir at room temperature for 15 hours after addition. The reaction solution was first washed with dilute hydrochloric acid solution, and then washed with distilled water until neutral. Dry with anhydrous magnesium sulfate, and filter with suction to obtain a light yellow filtrate; remove the solvent to obtain a dark yellow liquid. Transfer the liquid to a 500 mL single-necked bottle, add 300 mL of anhydrous acetone and anhydrous lithium bromide at the same time, the molar ratio of p-toluenesulfonate to anhydrous lithium bromide is 1:3, and stir at room temperature for 50 hours. Evaporate acetone to dryness, add 200 mL of petroleum ether, and let stand at -5°C for 4 hours. The precipitate was filtered to obtain a clear filtrate, and the solvent was evaporated to obtain the initial product. The primary product was purified by silica gel column chromatography, and the eluent was petroleum ether. The final product is a colorless transparent liquid with a yield of 64.8%.

Quaternization:

1-Bromo-cis-9-octadecene (66.3g, 0.2mol), N,N,N',N'-tetramethylethylenediamine (5g, 0.04mol), the molar ratio of the two was 5 : 1, 150mL of isopropanol was added into a 500mL single-necked bottle and refluxed for 100 hours. After cooling, the solvent was distilled off, recrystallized three times with ethanol-ethyl acetate, and dried in vacuo to obtain the product as a white waxy solid. Yield: 25.3%.

Claims (4)

1. the preparation method of a viscoelastic surfactant solution, first prepare Gemini surfactant, and then process and obtain corresponding quaternary ammonium base with strong basic ion exchange resin, through acid-base neutralization, obtain surfactant active ingredient again, last viscoelastic surfactant described in obtaining with inorganic salts are composite, is characterized in that, described inorganic salts are sodium nitrate, described Gemini surfactant is oleic acid base Gemini surfactant 18:1-2-18:1, is to obtain by following formula reaction:

solvent described in quaternized step is the mixed solvent of any one or any several arbitrary proportions of ethanol, isopropyl alcohol, acetonitrile, acetone;

During acid-base neutralization, acid used is nitric acid;

The mol ratio of oleyl alcohol and paratoluensulfonyl chloride is 1:1～3, and reaction temperature is-20 ℃～-5 ℃;

The viscoelastic surfactant solution of described low concentration is by surfactant active ingredient and inorganic salts are composite obtains, and wherein the active ingredient of surfactant is oleic acid base Gemini quaternary surfactant 18:1-2-18:12NO ₃, structural formula is as follows:

the mol ratio of surfactant active ingredient and sodium nitrate is 1:1～5.

2. the preparation method of viscoelastic surfactant solution according to claim 1, is characterized in that, described paratoluensulfonyl chloride reacts with oleyl alcohol after being first dissolved in carrene again.

3. the preparation method of viscoelastic surfactant solution according to claim 1, is characterized in that, the p-methyl benzenesulfonic acid ester of oleyl alcohol and the mol ratio of lithium bromide are 1:1～5, and reaction temperature is room temperature.

4. the preparation method of viscoelastic surfactant solution according to claim 1, is characterized in that, adds anhydrous propanone as reaction dissolvent when adding lithium bromide.

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