CN104801233A - Viscoelastic solution containing trimeric anionic surfactant component and preparation method thereof - Google Patents

Abstract

The invention relates to a preparation method of a viscoelastic surfactant solution obtained by compounding anionic and cationic surfactants containing a trimeric anionic surfactant component, wherein the structure of the main component anionic surfactant is as follows: Wherein the cationic surfactant can be dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) or cetyltrimethylammonium bromide (CTAB) any kind. The longer the hydrophobic chain length of the cationic surfactant, the better the effect of the viscoelastic solution formed with the trimeric anionic surfactant. The preparation of the surfactant solution includes two main processes of synthesis and compounding of the trimeric surfactant. The compounded surfactant solution exhibits the characteristics of elasticity at a low concentration, and the solution can be gel-like, which can be applied to oil field fracturing fluid, drag reducer and daily cleaning agent formulation.

Description

A kind of viscoelastic solution containing trimeric anionic surfactant component and preparation method thereof

technical field

The invention relates to a viscoelastic surfactant solution obtained by compounding anion and cation, in particular to a viscoelastic solution containing a trimeric anion surfactant component and a preparation method thereof, belonging to the field of surfactant science.

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. Oligomeric surfactants can exhibit strong viscoelasticity at lower concentrations, which has attracted widespread interest. Utilizing the molecular skeleton of oligomeric surfactants, and adjusting the type and length of hydrophobic chains and the type and ratio of counter ions, it is expected to obtain a surfactant solution system with better viscoelasticity.

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, and the concentration of the surfactant is relatively high, and the post-treatment is difficult, the present invention provides a viscoelastic surface obtained by compounding anionic and cationic surfactants A method for the preparation of an active agent solution. The trimeric surfactant prepared from phloroglucinol is used as the main component, and after compounding with a small amount of cationic surfactant, a surfactant viscoelastic solution with gel characteristics can be obtained.

The technical scheme of the present invention is: a kind of surfactant solution with viscoelasticity is obtained by compounding an anionic trimeric surfactant and a cationic surfactant, wherein the structural formula of the anionic trimeric surfactant is as follows:

The synthetic route of this anionic trimeric surfactant is as follows:

The obtained trimeric surfactant is made into a solution with a certain concentration, and then compounded with a cationic surfactant in a certain proportion to obtain a surfactant viscoelastic solution with gel characteristics.

Beneficial effect

After compounding the anionic trimeric surfactant solution with a small amount of cationic surfactant at a low concentration, a solution with good viscoelasticity can be obtained, which can significantly reduce the cost of use, and can be applied to oilfield fracturing fluid, drag reducer and daily Cleanser formulation.

Description of drawings

Fig. 1 Macroscopic picture of surfactant viscoelastic solution (the molar ratio of anionic and cationic surfactants is 1:0.2, and the concentration of anionic surfactant is 50mmol/L) stabilized for 48 hours.

Fig. 2 Dynamic shear diagrams of viscoelastic solutions of three surfactants (trimeric anionic surfactant concentration is 50mmol/L; G′ is storage modulus, solid symbols; G″ is loss modulus, hollow symbols).

The steady-state shear figure of three kinds of surfactant viscoelastic solutions of Fig. 3 (trimeric anionic surfactant concentration is 50mmol/L).

Detailed ways

Embodiment 1: the synthesis of α-bromotetradecanoic acid methyl ester. Add tetradecanoic acid (150g, 0.6568mol) into a 500ml three-necked flask, melt at 65°C, slowly add thionyl chloride (106.6g, 0.821mol) dropwise under stirring, raise the temperature to 90°C after the dropwise addition, add A little elemental iodine was used as an initiator, and liquid bromine (131.2g, 0.821mol) dried by concentrated sulfuric acid was slowly added dropwise, stirred and refluxed for 12 hours, and the temperature was lowered to 65°C, and anhydrous methanol (52.6g, 1.64mol) was added dropwise with stirring. mol), reflux for 2-4 hours after the addition. After cooling, wash with water 3-4 times, then wash the organic layer with 50 ml of saturated sodium sulfite solution until neutral, and finally wash with water 3-4 times. The organic layer was dried overnight by adding anhydrous magnesium sulfate. After filtration, the crude product was distilled under reduced pressure to obtain α-bromotetradecanoic acid methyl ester. 175～180℃.

Embodiment 2: the synthesis of anionic trimeric surfactant. Add phloroglucinol (2g, 0.016mol)\activated molecular sieve-treated N,N-dimethylformamide (30ml) into a 250ml three-necked flask, and nitrogen atmosphere prevents phenol oxidation. Add anhydrous potassium carbonate (18g, 0.13mol) and N,N-dimethylformamide (20ml), heat up to 60°C, add α-bromotetradecanoic acid methyl ester (17.8g, 0.056) in one go (dissolved In N,N-dimethylformamide), after 4h, the temperature was raised to 85°C, and the reaction was carried out for 24 hours. After cooling, a yellow filtrate was obtained by suction filtration, and N,N-dimethylformamide in the filtrate was removed under reduced pressure. Transfer the filtrate to a separatory funnel, first add 30ml of petroleum ether, and then add 50ml of ice water each time to extract the organic layer for 3-4 times. Add anhydrous magnesium sulfate to dry, remove petroleum ether under reduced pressure after filtration, and separate by column chromatography. The eluent starts with pure petroleum ether, and later uses a mixture of petroleum ether and ethyl acetate (volume ratio: 10:1). Add the above-mentioned terpolymer (10.8 g, 0.0127 mol), sodium hydroxide (1.78 g, 0.0446 mol) and 60 mL of absolute ethanol into a 250 mL three-necked flask. Stir at 70°C for 3-6 hours, during which white turbidity gradually occurs. After cooling, centrifuge, pour off the supernatant, wash the lower white solid with ethanol three times, and dry to obtain the product as white powder.

Embodiment 3: the preparation of viscoelastic surfactant solution. Prepare 3ml of trimeric surfactant solution of 50mmol/L, add appropriate amount of cationic surfactant solid to it respectively, make the molar ratio of anionic surfactant and cationic surfactant reach 1:0.1, 1:0.2 and 1 respectively :0.3, a series of viscoelastic surfactant solutions are obtained after dissolving.

Embodiment 4: the viscoelasticity measurement of cationic surfactant solution. The resulting viscoelastic surfactant solution was left to stand at 30°C for 48h, and the rheological properties were tested at 30°C. Before the dynamic scanning, the stress scanning is carried out to determine the linear viscoelastic region of the test sample, and the tests of the samples are all carried out in the linear viscoelastic region. See Figure 1 and Figure 2 for specific data. Figure 1 is the dynamic shear diagram of the test sample. It can be seen that within the tested frequency range, the elastic modulus of the sample is always greater than the viscous modulus, indicating that the sample has good elasticity. Figure 2 is the steady-state shear diagram of the sample. With the increase of the molar ratio of the cationic surfactant, the zero-shear viscosity of the sample increases sharply, up to 4×10 ⁴ Pa·s.

Claims (6)

1. A viscoelastic surfactant solution compounded by anionic and cationic surfactants is obtained by compounding a trimeric anionic surfactant and a cationic surfactant, wherein the structure of the anionic surfactant as follows: 2. A viscoelastic surfactant solution compounded by anionic and cationic surfactants is obtained by compounding trimeric anionic surfactants and cationic surfactants, wherein the cationic surfactants can be twelve Any one of alkyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) or cetyltrimethylammonium bromide (CTAB). The longer the hydrophobic chain length of the cationic surfactant, the better the effect of the viscoelastic solution formed with the trimeric anionic surfactant. 3. a kind of preparation method of viscoelastic surfactant solution as claimed in claim 1, is characterized in that, described trimerization anion surfactant is to obtain by following formula reaction: 4. the preparation method of viscoelastic surfactant solution according to claim 1 is characterized in that, the reaction of phloroglucinol and α-brominated fatty acid methyl ester will be carried out under the condition of cutting off air, used in the reaction The solvent is N,N-dimethylformamide or acetonitrile, and the molar weight of anhydrous potassium carbonate is 6-10 times that of phloroglucinol. 5. The preparation method of the viscoelastic surfactant solution according to claim 1, characterized in that the concentration range of the anionic surfactant in the compounded system is 30mmol/L～80mmol/L. 6. the preparation method of viscoelastic surfactant solution according to claim 1 is characterized in that, when anionic and cationic surfactants are compounded to prepare surfactant viscoelastic solution, the mole of cationic surfactant and anionic surfactant The ratio is 0.05:1 to 0.3:1.