A CO2-based extended surfactant and preparation method thereof

Abstract

The invention discloses a CO2-based extended surfactant and a preparation method thereof, and relates to the technical field of oilfield chemistry. The preparation method comprises the following steps: adding fatty alcohol polyoxyethylene ether, a catalyst, a co-catalyst and a small molecule epoxide to a reactor, injecting CO2 and reacting, after the reaction is completed, removing the gas in the reactor, terminating the reaction, and separating and purifying to obtain an intermediate; taking the intermediate and dissolving it, adding an aqueous solution of chloroacetic acid or its salt and an aqueous solution of sodium hydroxide, reacting at 20-60°C, after the reaction is completed, adjusting the pH to neutral, and separating and purifying it to obtain the intermediate. The invention uses a certain proportion of CO2 to prepare an extended surfactant, and realizes the conversion of CO2 into an extended nonionic surfactant with high interfacial activity; the surfactant has a lower CMC value and higher interfacial activity; the molecular structure of the surfactant is adjustable, the molecular weight is relatively low, and the molecular weight distribution is narrow.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry, in particular to a CO2-based extended surfactant and a preparation method thereof. Background Art

[0002] Surfactants are widely used in the fields of petroleum industry, daily chemicals, food processing, agriculture and pharmaceuticals. Nonionic surfactants such as fatty alcohol polyoxyethylene ethers (AEO) prepared from natural oils are high-quality raw materials for the preparation of environmentally friendly surfactants. In recent years, derivatives of AEO have also developed rapidly. Extended surfactants are a new type of anionic-nonionic surfactants. Their molecular structure contains one or more polyoxyethylene (EO) or polyoxypropylene (PO) segments, which are located between the hydrophobic chain and the hydrophilic head group. Through this structural extension, extended surfactants are different from traditional surfactants in nature and have the following characteristics: high interfacial activity over a wide temperature range, high salt tolerance, ability to generate ultra-low interfacial tension, low cost, low toxicity and environmental protection. At present, the preparation process of most extended surfactants requires the use of petroleum-based raw materials, and the production process involves harmful by-products, which have a certain impact on the environment and human health.

[0003] Carbon dioxide is a greenhouse gas, but also a cheap, abundant and stable carbon resource. The resource utilization of carbon dioxide for the preparation of high value-added chemicals is one of the current hot research topics in the field of chemistry. However, existing research on the use of carbon dioxide to prepare surfactants is basically blank. Summary of the invention

[0004] To solve at least one of the above problems, the present invention provides a CO2-based extended surfactant and a preparation method thereof.

[0005] The technical solution of the present invention is: a method for preparing a CO2-based extended surfactant, comprising the following steps:

[0006] S1, add fatty alcohol polyoxyethylene ether, catalyst (R,R)-(salcy)-CoOBzF5, co-catalyst PPN-Cl and small molecule epoxide into a reactor, inject CO2 and maintain the pressure in the reactor at 2-15MPa, react at 30-60°C for 12-24h, after the reaction is completed, remove the gas in the reactor, add chloroform to purify it, and terminate the reaction with 5% HCl methanol solution, and then separate and purify it to obtain an intermediate; in parts by mass, the amount of the fatty alcohol polyoxyethylene ether added is 2000-3000 parts, and the amount of the small molecule epoxide added is 400-870 parts;

[0007] S2, taking the intermediate and dissolving it, adding an aqueous solution of chloroacetic acid or its salt and an aqueous solution of sodium hydroxide, reacting at 20-60° C. for 2-4 hours, adjusting the pH to neutral after the reaction, and then separating and purifying it; in terms of molar ratio, the addition ratio of the intermediate, the chloroacetic acid or its salt and the sodium hydroxide is 1:1.2-1.8:1.2-2.0.

[0008] One embodiment of the present invention is that in S1, the molecular weight of the fatty alcohol polyoxyethylene ether is 360-1100. Too large a molecular weight will reduce its surface activity.

[0009] One embodiment of the present invention is that, by weight, the amount of the catalyst added is 0.5 to 1 part, and the amount of the co-catalyst added is 0.5 to 1 part. This is the conventional amount of the catalyst and the co-catalyst added.

[0010] An embodiment of the present invention is that the small molecule epoxide is at least one of ethylene oxide and propylene oxide.

[0011] One embodiment of the present invention is that, in S1, the amount of chloroform added is at least 3 times the total amount of the reaction product of the reaction solution added; the amount of the 5% HCl methanol solution added is 1.1 to 1.4 times the total mass of the reaction monomers. The unreacted monomers in the reaction solution are extracted and separated by the added chloroform, and the reaction is terminated by the added 5% HCl methanol solution to avoid excessive molecular weight.

[0012] One embodiment of the present invention is that in S1, the separation and purification step is as follows: take the reaction product, separate it and take the non-chloroform layer, add excess pentane, and after a precipitate is generated at 2-5°C, take the precipitate and dry it.

[0013] One embodiment of the present invention is that in S2, an aqueous solution of chloroacetic acid or a salt thereof and an aqueous solution of sodium hydroxide are alternately added dropwise to the intermediate solution, and the alternating addition is to first dropwise add a few drops or a few milliliters of an aqueous solution of chloroacetic acid or a salt thereof, and then dropwise add an input or a few milliliters of an aqueous solution of sodium hydroxide, and the steps are performed alternately. In this process, the amount of the aqueous solution of chloroacetic acid or a salt thereof and the aqueous solution of sodium hydroxide added each time should not be too much, and usually does not exceed 1.5 mL.

[0014] One embodiment of the present invention is that in S2, the separation and purification step is as follows: adding chloroform to extract it, after the extraction is completed, taking the non-chloroform layer, and removing the solvent by distillation under reduced pressure to obtain the product.

[0015] One embodiment of the present invention is that in S2, the solvent of the intermediate is water, ethanol or N , N -One of the dimethylformamides.

[0016] Another object of the present invention is to provide a CO2-based extended surfactant, which is prepared by any of the above methods. The ideal structural formula of the surfactant finally prepared is as follows:

[0017]

[0018] In the formula, the range of n is 4-10, the range of a is 0-8, the range of m is 0-8, and a+m<12. Beneficial Effects

[0019] (1) The present invention utilizes a certain proportion of CO2 to prepare an extended surfactant, thereby converting CO2 into an extended nonionic surfactant with high interfacial activity;

[0020] (2) It has a lower CMC value and higher interfacial activity;

[0021] (3) The molecular structure of the extended part is adjustable, the molecular weight is relatively low, and the molecular weight distribution is narrow; BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the H NMR spectrum of the product of Example 1. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention will be described clearly and completely below with reference to examples and drawings. Obviously, the described examples are only some embodiments of the present invention, rather than all embodiments.

[0024] In the following examples, unless otherwise specified, the drugs used are conventional commercial products.

[0025] In the following examples, unless otherwise specified, all methods used are routine operations in the art.

[0026] Example 1: S1. Take 5 mg of catalyst (R,R)-(salcy)-CoOBzF5, 5 mg of co-catalyst PPN-Cl, 4.15 g of propylene oxide and 20 g of dry polyoxyethylene fatty alcohol ether and add them to a reactor, inject CO2 gas into the reactor and pressurize it to 10 MPa, adjust the temperature of the reactor to 30°C, and react for 18 hours. After the reaction is completed, reduce the pressure to discharge the gas in the reactor, then add chloroform to the reactor, and use 5% HCl methanol solution to terminate the reaction; then add the reaction solution to pentane to induce polymer precipitation, take the precipitated product, and dry it under reduced pressure. The yield is measured to be 85%.

[0027] S2, take 5g of the product of S1 and dissolve it in N , N- dimethylformamide (DMF), then alternately add (15 drops each, alternately) 2.6g of chloroacetic acid and 3.2g of sodium hydroxide aqueous solution, which can avoid the problem of product color deepening and side reactions, adjust the temperature to 40°C and react for 4h. After the reaction, add dilute hydrochloric acid to adjust the pH of the reaction solution to 6. Add chloroform to extract the above product several times. After extraction, take the chloroform layer, and remove the solvent by vacuum distillation to obtain a surfactant.

[0028] Example 2: S1. Take 6 mg of catalyst (R,R)-(salcy)-CoOBzF5, 6 mg of co-catalyst PPN-Cl, 4.98 g of propylene oxide, 1.77 g of ethylene oxide (converted to mass) and 25 g of dry polyoxyethylene fatty alcohol ether and add them to a reactor. Inject CO2 gas into the reactor and pressurize it to 12 MPa. Adjust the temperature of the reactor to 35°C and react for 12 hours. After the reaction is completed, reduce the pressure to discharge the gas in the reactor. Then add chloroform to the reactor and terminate the reaction with 5% HCl in methanol. Then add the reaction solution to pentane to induce precipitation of the polymer. Take the precipitated product and dry it under reduced pressure. The yield is measured to be 88%.

[0029] S2, take 5g of the product of S1 and dissolve it in N,N-dimethylformamide (DMF), then alternately add (15 drops each, alternately) 2.6g of chloroacetic acid and 3.2g of sodium hydroxide aqueous solution, which can avoid the problem of product color deepening and side reactions, adjust the temperature to 40°C and react for 4h. After the reaction, add dilute hydrochloric acid to adjust the pH of the reaction solution to 6. Add chloroform to extract the above product several times. After extraction, take the chloroform layer, and remove the solvent by vacuum distillation to obtain a surfactant.

[0030] Example 3: S1. Take 5 mg of catalyst (R,R)-(salcy)-CoOBzF5, 5 mg of co-catalyst PPN-Cl, 4.98 g of propylene oxide and 20 g of dry polyoxyethylene fatty alcohol ether and add them to a reactor, inject CO2 gas into the reactor and pressurize it to 8 MPa, adjust the temperature of the reactor to 30°C, and react for 16 hours. After the reaction is completed, reduce the pressure to discharge the gas in the reactor, then add chloroform to the reactor, and use 5% HCl methanol solution to terminate the reaction; then add the reaction solution to pentane to induce polymer precipitation, take the precipitated product, and dry it under reduced pressure. The yield is measured to be 83%.

[0031] S2, take 5g of the product of S1 and dissolve it in N , N- dimethylformamide (DMF), then alternately add (15 drops each, alternately) 2.6g of chloroacetic acid and 3.2g of sodium hydroxide aqueous solution, which can avoid the problem of product color deepening and side reactions, adjust the temperature to 40°C and react for 4h. After the reaction, add dilute hydrochloric acid to adjust the pH of the reaction solution to 6. Add chloroform to extract the above product several times. After extraction, take the chloroform layer, and remove the solvent by vacuum distillation to obtain a surfactant.

[0032] Example 4: S1. Take 7 mg of catalyst (R,R)-(salcy)-CoOBzF5, 7 mg of co-catalyst PPN-Cl, 4.15 g of propylene oxide, 1.3 g of ethylene oxide (converted to mass) and 30 g of dry polyoxyethylene fatty alcohol ether and add them to a reactor. Inject CO2 gas into the reactor and pressurize it to 15 MPa. Adjust the temperature of the reactor to 30°C and react for 20 hours. After the reaction is completed, reduce the pressure to discharge the gas in the reactor. Then add chloroform to the reactor and terminate the reaction with 5% HCl in methanol. Then add the reaction solution to pentane to induce polymer precipitation. Take the precipitated product and dry it under reduced pressure. The yield is measured to be 90%.

[0033] S2, take 5g of the product of S1 and dissolve it in N , N - dimethylformamide (DMF), then alternately add 2.6g of chloroacetic acid and 3.2g of sodium hydroxide aqueous solution, which can avoid the problem of product color deepening and side reactions, adjust the temperature to 40°C and react for 4h. After the reaction, add dilute hydrochloric acid to adjust the pH of the reaction solution to 6. Add chloroform to extract the above product several times. After extraction, take the chloroform layer, and remove the solvent by vacuum distillation to obtain a surfactant.

[0034] Example 5: S1. Take 6 mg of catalyst (R,R)-(salcy)-CoOBzF5, 6 mg of co-catalyst PPN-Cl, 4.15 g of propylene oxide and 20 g of dry polyoxyethylene fatty alcohol ether and add them to a reactor, inject CO2 gas into the reactor and pressurize it to 10 MPa, adjust the temperature of the reactor to 35°C, and react for 20 hours. After the reaction is completed, reduce the pressure to discharge the gas in the reactor, then add chloroform to the reactor, and use 5% HCl methanol solution to terminate the reaction; then add the reaction solution to pentane to induce polymer precipitation, take the precipitated product, and dry it under reduced pressure. The yield is measured to be 88%.

[0035] S2, take 5g of the product of S1 and dissolve it in N , N- dimethylformamide (DMF), then alternately add (15 drops each, alternately) 2.6g of chloroacetic acid and 3.2g of sodium hydroxide aqueous solution, which can avoid the problem of product color deepening and side reactions, adjust the temperature to 40°C and react for 4h. After the reaction, add dilute hydrochloric acid to adjust the pH of the reaction solution to 6. Add chloroform to extract the above product several times. After extraction, take the chloroform layer, and remove the solvent by vacuum distillation to obtain a surfactant.

[0036] In order to further illustrate the effect of the embodiment of the present invention, a specific method is used to test it below.

[0037] 1. Characterization

[0038] The surfactant prepared in Example 1 was measured using a Bruker 400M nuclear magnetic resonance spectrometer. The final test results are as follows: Figure 1 As shown, from Figure 1 It can be seen that the synthesized surfactant contains characteristic peaks of hydrogen connected to the ether bond and the carboxylic acid group at the positions of 5.2 and 3.7 ppm, indicating that the synthesized substance is the target product.

[0039] 2. Performance Testing

[0040] The surfactants prepared in Examples 1 to 5 were tested for their physical and chemical properties, wherein the oil-water interfacial tension was determined by the spinning drop method (the crude oil was Changqing crude oil), the CMC value was determined by the hanging plate method, and the molecular weight and molecular weight distribution were determined by size exclusion chromatography. The final results are shown in Table 1.

[0041] Table 1 Physical and chemical properties test results of surfactants in embodiments of the present invention

[0042]

[0043] As can be seen from Table 1, the surfactant prepared in the embodiment of the present invention has a lower CMC value and a lower oil-water interfacial tension, and has a relatively low molecular weight and a narrow molecular weight distribution.

[0044] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a CO2-based extended surfactant, characterized in that: The following steps are involved: S1. Add fatty alcohol polyoxyethylene ether, catalyst (R,R)-(salcy)-CoOBzF5, co-catalyst PPN-Cl and small molecule epoxide into a reactor, inject CO2 and maintain the pressure in the reactor at 2-15MPa, react at 30-60°C for 12-24h, remove the gas in the reactor after the reaction, add chloroform to purify it, terminate the reaction with 5% HCl methanol solution, and then separate and purify it to obtain an intermediate; in parts by mass, the amount of the fatty alcohol polyoxyethylene ether is 2000-3000 parts, the amount of the small molecule epoxide is 400-870 parts, the amount of the catalyst is 0.5-1 part, and the amount of the co-catalyst is 0.5-1 part; the small molecule epoxide is at least one of ethylene oxide and propylene oxide; S2, take the intermediate and dissolve it, add an aqueous solution of chloroacetic acid or its salt and an aqueous solution of sodium hydroxide, react at 20-60° C. for 2-4 hours, adjust the pH to neutral after the reaction, and then separate and purify it; in terms of molar ratio, the addition ratio of the intermediate, the chloroacetic acid or its salt and the sodium hydroxide is 1:1.2-1.8:1.2-2.0; alternately add the aqueous solution of chloroacetic acid or its salt and the aqueous solution of sodium hydroxide dropwise to the intermediate solution.

2. The method according to claim 1, characterized in that In S1, the molecular weight of the fatty alcohol polyoxyethylene ether is 360-1100.

3. The method according to claim 1, characterized in that In S1, the amount of chloroform added is at least 3 times the total amount of the reaction product of the reaction solution added; the amount of the 5% HCl methanol solution added is 1.1-1.4 times the total mass of the reaction monomers.

4. The method according to claim 1, characterized in that In S1, the separation and purification steps are as follows: take the reaction product, separate it and take the non-chloroform layer, add excess pentane, and after precipitation is generated at 2-5°C, take the precipitate and dry it.

5. The method according to claim 1, characterized in that In S2, the separation and purification steps are as follows: adding chloroform to extract it, after the extraction is completed, taking the non-chloroform layer, and distilling under reduced pressure to remove the solvent to obtain the product.

6. The method according to claim 1, characterized in that In S2, the solvent of the intermediate is water, ethanol or N , N -One of the dimethylformamides.

7. A CO2-based extendable surfactant, prepared by the method described in any one of claims 1 to 6.

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