Perfluoropolyether anionic-nonionic surfactant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surfactants, and particularly discloses a perfluoropolyether anionic-nonionic surfactant as well as a preparation method and application thereof, the structural formula of the perfluoropolyether anionic-nonionic surfactant is as follows: in the # imgabs0 # formula, Rf is Y-type perfluoropolyether, and the molecular weight of the Y-type perfluoropolyether is 300-2000g / mol; and x, y and z are integers from 1 to 20. The perfluoropolyether anionic-nonionic surfactant disclosed by the invention can obviously reduce oil-water interfacial tension and water surface tension, and especially has a remarkable effect when being combined with the surface of sandstone; good temperature resistance and salt resistance are achieved; the surfactant has good wettability on the sandstone surface, and can be used as a surfactant additive for oil exploitation.

Description

Technical Field

[0001] The invention relates to the technical field of surfactants, and in particular to a perfluoropolyether anionic nonionic surfactant and a preparation method and application thereof. Background Art

[0002] Fluorocarbon surfactants are surfactants in which part or all of the hydrogen atoms on the hydrocarbon chain of a common surfactant molecule are replaced by fluorine atoms. Fluorocarbon surfactants have the advantages of high surface activity, excellent heat resistance and chemical stability; they are widely used in industries such as chemistry, machinery, electronics, petroleum, as well as household products and other fields.

[0003] Fluorocarbon surfactants have been studied in depth and widely used, such as perfluorooctane carboxylic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and surfactants with various linear or branched perfluoroalkyl groups as fluorocarbon chains. However, these perfluorocarboxylates / sulfonates are currently the most difficult organic pollutants to degrade; and linear alkyl fluorocarbon surfactants have poor chain flexibility, resulting in poor solubility.

[0004] Fluorocarbon surfactants are divided into anionic, cationic, amphoteric and nonionic types according to the dissociation properties of polar groups. Anionic surfactants have the characteristics of low cost, high interfacial activity, low adsorption on sandstone surface, good temperature resistance, etc., and have important applications in chemical oil recovery. However, their salt resistance is poor and the critical micelle concentration (CMC) is high. The hydrophilic groups of non-ionic surfactants usually contain ether groups and hydroxyl groups, which have better compatibility with water and organic solvents, will not ionize in aqueous solutions, have good salt resistance, acid and alkali resistance, electrolyte resistance and good compatibility, so they are insensitive to the acidity and alkalinity of the solution and electrolytes, and due to the chemical stability of the fluorocarbon chain, they can be used in strong acid and alkaline environments. Although non-ionic compounds have strong salt resistance, they have low turbidity points and cannot be used in formations with high turbidity points, and have poor temperature resistance.

[0005] By introducing anionic groups on the basis of nonionic compounds, the salt resistance and cloud point of surfactants can be improved. However, at present, most anionic-nonionic fluorocarbon surfactants are still seriously polluting the environment, are still non-degradable, and have poor ability to reduce surface tension and interfacial tension. They cannot achieve high efficiency in small quantities when used in the field of oil extraction; they are more sensitive to inorganic salts, and their various performances will be significantly reduced in high-salt oil reservoirs. Summary of the invention

[0006] The object of the present invention is to provide a perfluoropolyether anionic-nonionic surfactant, which can effectively reduce the oil-water interfacial tension and has good temperature and salt resistance.

[0007] In addition, the present invention also provides a preparation method and application of the above-mentioned perfluoropolyether anionic-nonionic surfactant.

[0008] The present invention is achieved through the following technical solutions:

[0009] A perfluoropolyether anionic nonionic surfactant, the structural formula of which is shown below:

[0010]

[0011] In the formula, R f It is a Y-type perfluoropolyether, the molecular weight of the Y-type perfluoropolyether is 300-2000 g / mol; x, y, and z are all integers of 1-20.

[0012] The perfluoropolyether anionic-nonionic surfactant of the present invention can significantly reduce the oil-water interfacial tension and the water surface tension, and is particularly effective when applied to the surface of sandstone; it has good temperature and salt resistance; it has good wettability on the surface of sandstone, and can be used as a surfactant additive for oil extraction.

[0013] Furthermore, the perfluoropolyether anionic nonionic surfactant of the present invention uses perfluoropolyether as a fluorine-containing chain segment and is more environmentally friendly than PFOA.

[0014] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0015] S1, subjecting Y-type perfluoropolyether alcohol to an esterification reaction with 3-butene-1-ol to obtain an intermediate 1;

[0016] S2. The intermediate 1 prepared in step S1 is polymerized with sodium styrene sulfonate and dodecyl acrylate to obtain a perfluoropolyether anionic nonionic surfactant.

[0017] The present invention can be achieved by different fluorocarbon chain lengths, i.e., R f The molecular weight of the product is controlled, and the amount of sodium styrene sulfonate and dodecyl acrylate added is controlled during the preparation process to control the length of the alkyl chain, thereby achieving control of the product's hydrophilicity and lipophilicity, surface tension, and tertiary oil recovery driving oil performance.

[0018] In a preferred embodiment, the specific process of step S1 is as follows:

[0019] Mix Y-type perfluoropolyether alcohol with solvent 1, then add catalyst 1 and acid binding agent, and then drop 3-butene-1-ol; after the dropwise addition is completed, heat to the required temperature, quench the reaction, wash, and obtain intermediate 1.

[0020] Wherein, the mass ratio of Y-type perfluoropolyether alcohol, 3-butene-1-ol, catalyst 1 and acid binding agent is 1:1:0.5:0.3.

[0021] In a preferred embodiment, the solvent 1 is a non-fluorinated polar aprotic solvent; the catalyst 1 is an organic weak acid. The fluorinated polar aprotic solvent includes ethylene glycol dimethyl ether and acetonitrile; and the organic weak acid includes benzenesulfonic acid and p-toluenesulfonic acid.

[0022] In a preferred embodiment, in step S1, the reaction temperature is 70-100°C.

[0023] In a preferred embodiment, in step S1, the dropping speed of 3-butene-1-ol is 8 to 20 mL / min.

[0024] In a preferred embodiment, the specific process of step S2 is:

[0025] The intermediate 1 is dissolved in deionized water; the pH is adjusted to neutral, the catalyst 2 is added, and after stirring and heating to the required temperature, the sodium styrene sulfonate aqueous solution and the dodecyl acrylate-isopropanol solution are slowly added dropwise. After the addition is completed, the reaction and purification are carried out at a certain temperature to obtain a perfluoropolyether anionic-nonionic surfactant.

[0026] In a preferred embodiment, in step S2, the reaction temperature is 60-90°C; and the catalyst 2 comprises ammonium persulfate.

[0027] In a preferred embodiment, in step S2, the dropping speeds of the sodium styrene sulfonate aqueous solution and the lauryl acrylate-isopropanol solution are both 5 to 16 mL / min.

[0028] The invention discloses an application of a perfluoropolyether anionic nonionic surfactant in oil production, including application in high-salinity oil reservoirs.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] The perfluoropolyether anionic-nonionic structure of the present invention can wet and spread on the sandstone surface, effectively reducing the oil-water interfacial tension; has good temperature and salt resistance, can be used in high-salt and high-temperature oil production environments; and has good wettability on the sandstone surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0032] Figure 1 The infrared spectrum of the anionic-nonionic surfactant prepared in Example 1 of the present invention;

[0033] Figure 2 The hydrogen NMR spectrum (heavy water) of the anionic nonionic surfactant prepared in Example 1 of the present invention;

[0034] Figure 3 The infrared spectrum of the anionic nonionic surfactant prepared in Comparative Example 1 of the present invention;

[0035] Figure 4 The hydrogen nuclear magnetic spectrum (heavy water) of the anionic nonionic surfactant prepared in Comparative Example 1 of the present invention;

[0036] Figure 5 This is the infrared spectrum of the anionic nonionic surfactant prepared in Comparative Example 2 of the present invention;

[0037] Figure 6 The hydrogen nuclear magnetic spectrum (heavy water) of the anionic nonionic surfactant prepared in Comparative Example 2 of the present invention;

[0038] Figure 7 The infrared spectrum of the anionic nonionic surfactant prepared in Comparative Example 3 of the present invention;

[0039] Figure 8 The hydrogen nuclear magnetic spectrum (heavy water) of the anionic nonionic surfactant prepared in Comparative Example 3 of the present invention;

[0040] Fig. 9 The infrared spectrum of the anionic nonionic surfactant prepared in Comparative Example 4 of the present invention;

[0041] Fig.10 This is the H NMR spectrum (heavy water) of the anionic nonionic surfactant prepared in Comparative Example 4 of the present invention;

[0042] Fig.11 This is the infrared spectrum of the anionic nonionic surfactant prepared in Comparative Example 5 of the present invention;

[0043] Fig.12 This is the hydrogen NMR spectrum (heavy water) of the anionic nonionic surfactant prepared in Comparative Example 5 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. The schematic implementation mode of the present invention and its description are only used to explain the present invention and are not intended to limit the present invention. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0045] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details do not have to be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, known structures, materials or methods are not specifically described. The materials, instruments and reagents used in the following examples, unless otherwise specified, can be obtained from commercial sources. The technical means used in the examples, unless otherwise specified, are conventional means well known to those skilled in the art.

[0046] Example:

[0047] In order to solve the problems that the existing anionic-nonionic surfactants are non-degradable, have poor ability to reduce surface tension and interfacial tension, cannot achieve high efficiency in small quantities when used in the field of oil extraction, and are relatively sensitive to inorganic salts, this embodiment provides a perfluoropolyether anionic-nonionic surfactant, the structural formula of which is as follows:

[0048]

[0049] In the formula, R f It is a Y-type perfluoropolyether, that is Wherein, the value of m is 0-12, the value of n is 0-29; the molecular weight of the Y-type perfluoropolyether is 300-2000 g / mol; x, y, and z represent the degree of polymerization, which are all integers of 1-20.

[0050] The preparation method of the above-mentioned perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0051] S1. Under nitrogen protection, add all-Y-type fluoropolyether alcohol and solvent 1 into a flask, add catalyst 1 and acid binding agent, slowly drip 3-butene-1-ol, heat to the required temperature after dripping, quench the reaction after a certain period of reaction, wash with saturated sodium chloride solution 3 times, and recrystallize at low temperature in deionized water to remove residual sodium chloride to obtain intermediate 1. The mass ratio of Y-type perfluoropolyether alcohol, 3-butene-1-ol, catalyst 1, and acid binding agent is 1:1:0.5:0.3.

[0052] Among them, solvent 1 is at least one of non-fluorinated polar aprotic solvents ethylene glycol dimethyl ether and acetonitrile; catalyst 1 is an organic weak acid, which can be at least one of benzenesulfonic acid and p-toluenesulfonic acid; the reaction temperature is 70-100°C; the reaction pressure is normal pressure; the dripping rate of 3-butene-1-ol is 8-20mL / min, preferably 12ml / min.

[0053] S2. Dissolve the intermediate 1 in deionized water and add it to the reactor. Adjust the pH to neutral with a certain concentration of sodium hydroxide solution. Add the catalyst 2. After stirring and heating to the required temperature, slowly add a certain concentration of sodium styrene sulfonate aqueous solution and dodecyl acrylate-isopropanol solution. After the addition is completed, react at a certain temperature for a period of time. Purify the product to obtain the perfluoropolyether anionic-nonionic surfactant.

[0054] Wherein, catalyst 2 includes ammonium persulfate; the dripping rate of sodium styrene sulfonate aqueous solution is 5-16 mL / min, preferably 10 ml / min; the dripping rate of dodecyl acrylate-isopropanol solution is 5-16 mL / min, preferably 10 ml / min; the reaction temperature is 60-90° C.; and the reaction pressure is normal pressure.

[0055] The specific synthetic route is as follows:

[0056]

[0057] The perfluoropolyether anionic-nonionic surfactant prepared in this embodiment can significantly reduce the oil-water interfacial tension and the water surface tension, and is particularly effective when applied to the surface of sandstone; it has good temperature and salt resistance; it has good wettability on the sandstone surface, and can be used as a surfactant additive for oil extraction and can be used in high-salt oil reservoirs.

[0058] In order to better illustrate the performance of the perfluoropolyether anionic-nonionic surfactant of this embodiment, the following case is used for illustration.

[0059] Embodiment 1:

[0060] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0061] S1. Under nitrogen protection, 420.00 g of perfluoropolyether acyl fluoride (Mn = 400 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, and the mixture was heated to 75°C and refluxed with stirring for 5 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain intermediate 1.

[0062] 396.68 g, yield 90.56%.

[0063] S2, dissolve 396.68g of intermediate 1 in 1000mL deionized water, adjust pH to 7 with 10% mass concentration sodium hydroxide solution, add to 2L four-necked flask and stir continuously, heat to 75°C, and slowly drip 400mL (0.08mol / L) ammonium persulfate-water solution, 300mL (1.2mol / L) sodium styrene sulfonate-water solution and 60mL (4mol / L) dodecyl acrylate-isopropanol solution at the same time. After the dripping is completed, the reaction is carried out at 75°C for 5h to obtain 2284.34g of orange-red viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 430.70g of light yellow powder with a yield of 79.93%.

[0064] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this example is as follows Figure 1 As shown, the nuclear magnetic hydrogen spectrum (heavy water) is as follows Figure 2 shown.

[0065] Embodiment 2:

[0066] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0067] S1. Under nitrogen protection, 630.00 g of perfluoropolyether acyl fluoride (Mn = 600 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, and the mixture was heated to 75 °C and refluxed with stirring for 5 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain intermediate 1.

[0068] 601.45 g, yield 94.30%.

[0069] S2, dissolve 601.45g of intermediate 1 in 1000mL of deionized water, adjust to pH=7 with 10% mass concentration of sodium hydroxide solution, add to a 2L four-necked flask and stir continuously, heat to 75°C, and then slowly drip 400mL (0.08mol / L) of ammonium persulfate-water solution, 300mL (1.2mol / L) of sodium styrene sulfonate-water solution and 60mL (4mol / L) of dodecyl acrylate-isopropanol solution. After the dripping is completed, the reaction is carried out at 75°C for 5h to obtain 2434.34g of orange-yellow viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 648.22g of light yellow powder with a yield of 82.15%.

[0070] Embodiment 3:

[0071] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0072] S1. Under nitrogen protection, 1170.75 g of perfluoropolyether acyl fluoride (Mn=1115 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added into a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 15 min, the temperature was raised to 75°C, refluxed with stirring, and reacted for 5 h to obtain a yellow oily liquid. The mixture was washed three times with 800 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain 1994.2 g of the intermediate with a yield of 76.24%.

[0073] S2, dissolve 994.2g of intermediate 1 in 1500mL deionized water, adjust pH to 7 with 10% mass concentration sodium hydroxide solution, add to 5L four-necked flask and stir continuously, heat to 75°C, and slowly add 400mL (0.08mol / L) ammonium persulfate-water solution, 300mL (1.2mol / L) sodium styrene sulfonate-water solution and 60mL (4mol / L) dodecyl acrylate-isopropanol solution at the same time. After the addition is completed, react at 75°C for 8h to obtain 3201.27g of yellow viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 1133.55g of light yellow powder with a yield of 78.91%.

[0074] Embodiment 4:

[0075] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0076] S1. Under nitrogen protection, 2101.1 g of perfluoropolyether acyl fluoride (Mn=2001 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added into a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 60 min, the temperature was raised to 75°C, refluxed with stirring, and reacted for 8 h to obtain a colorless oily liquid. The liquid was washed three times with 1000 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain 11884.2 g of the intermediate with a yield of 72.12%.

[0077] S2, dissolve 1884.2g of intermediate 1 in 3000mL of deionized water, adjust to pH=7 with 10% mass concentration of sodium hydroxide solution, add to a 5L four-necked flask and stir continuously, heat to 75°C, and slowly drip 400mL (0.08mol / L) of ammonium persulfate-water solution, 300mL (1.2mol / L) of sodium styrene sulfonate-water solution and 60mL (4mol / L) of dodecyl acrylate-isopropanol solution at the same time. After the dripping is completed, the reaction is carried out at 75°C for 10h to obtain 4147.54g of colorless viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 2056.93g of light yellow powder with a yield of 77.27%.

[0078] Comparative Example 1:

[0079] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0080] Under nitrogen protection, 630.00 g of perfluoropolyether acyl fluoride (Mn = 600 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, the temperature was raised to 75°C, refluxed with stirring, and reacted for 8 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain 598.42 g of intermediate 1 with a yield of 92.67%.

[0081] The perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is intermediate 1.

[0082] The synthesis path of step S1 of this comparative example is as follows:

[0083]

[0084] Among them, m=1, n=2.

[0085] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is as follows Figure 3 As shown, the nuclear magnetic hydrogen spectrum (heavy water) is as follows Figure 4 shown.

[0086] Comparative Example 2:

[0087] A method for preparing a perfluoropolyether anionic-nonionic surfactant comprises the following steps:

[0088] S1. Under nitrogen protection, 630.00 g of perfluoropolyether acyl fluoride (Mn = 600 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, heated to 75 °C, refluxed and stirred, and reacted for 5 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain intermediate 1.

[0089] 601.45 g, yield 94.30%.

[0090] S2, dissolve 601.45g of intermediate 1 in 1000mL of deionized water, adjust to pH=7 with 10% mass concentration of sodium hydroxide solution, add to a 2L four-necked flask and stir continuously, heat to 75°C, and slowly add 400mL (0.08mol / L) of ammonium persulfate-water solution. After the addition is completed, react at 75°C for 5h to obtain 2434.34g of orange-yellow viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 532.92g of light yellow powder, with a yield of 67.27%.

[0091] The synthesis path of step S2 of this comparative example is as follows:

[0092]

[0093] R f Right now Among them, m=1, n=2, z=12.

[0094] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is as follows Figure 5 As shown, the nuclear magnetic hydrogen spectrum (heavy water) is as follows Figure 6 shown.

[0095] Comparative Example 3:

[0096] A method for preparing a perfluoropolyether nonionic surfactant comprises the following steps:

[0097] S1. Under nitrogen protection, 630.00 g of perfluoropolyether acyl fluoride (Mn = 600 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, and the mixture was heated to 75 °C and refluxed with stirring for 5 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain intermediate 1.

[0098] 587.96 g, yield 89.91%.

[0099] S2, dissolve 587.96g of intermediate 1 in 1000mL of deionized water, adjust to pH=7 with 10% mass concentration of sodium hydroxide solution, add to a 2L four-necked flask and stir continuously, heat to 75°C, and slowly drip 400mL (0.08mol / L) of ammonium persulfate-water solution and 300mL (1.2mol / L) of sodium styrene sulfonate-water solution at the same time. After the dripping is completed, the reaction is carried out at 75°C for 5h to obtain 1566.36g of light yellow liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 503.76g of light yellow powder, with a yield of 77.22%.

[0100] The synthesis path of step S2 of this comparative example is as follows:

[0101]

[0102] R f Right now Among them, m=1, n=2, x=6, y=5.

[0103] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is as follows Figure 7 As shown, the nuclear magnetic hydrogen spectrum (heavy water) is as follows Figure 8 shown.

[0104] Comparative Example 4:

[0105] A method for preparing a perfluoropolyether nonionic surfactant comprises the following steps:

[0106] S1. Under nitrogen protection, 630.00 g of perfluoropolyether acyl fluoride (Mn = 600 g / mol), 400 ml of acetonitrile, and 22.30 g (0.135 mol) of p-toluenesulfonic acid were added to a 2L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, and the mixture was heated to 75 °C and refluxed with stirring for 5 h to obtain an orange-yellow liquid. The mixture was washed three times with 500 mL of saturated sodium chloride solution, and the residual sodium chloride was removed by low-temperature recrystallization in deionized water to obtain intermediate 1.

[0107] 592.14 g, yield 90.51%.

[0108] S2, dissolve the intermediate 1 592.14 gg in 3000 mL of deionized water, adjust the pH to 7 with 10% mass concentration of sodium hydroxide solution, add it to a 5L four-necked flask and stir it continuously. After heating to 75°C, slowly add 400 mL (0.08 mol / L) of ammonium persulfate-water solution and 300 mL (1.2 mol / L) of dodecyl acrylate-isopropanol solution. After the addition is completed, react at 75°C for 10 hours to obtain 4147.54 g of colorless viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry it at 120°C to obtain 2056.93 g of light yellow powder with a yield of 77.27%.

[0109] The synthesis path of step S2 of this comparative example is as follows:

[0110]

[0111] R f Right now Among them, m=1, n=2, y=8, z=5.

[0112] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is as follows Fig. 9 As shown, the nuclear magnetic hydrogen spectrum (deuterated methanol) is as follows Fig.10 shown.

[0113] Comparative Example 5:

[0114] A method for preparing a fluorinated anionic nonionic surfactant comprises the following steps:

[0115] S1. Under nitrogen protection, 114.02 g (1 mol) of trifluoroacetic acid and 400 ml of dichloromethane were added to a 2 L strictly dried three-necked flask, and 72.11 g (1 mol) of 3-butene-1-ol was slowly added dropwise at room temperature. After the addition was completed, the mixture was stirred for 5 min, the temperature was raised to 55 ° C, refluxed with stirring, and reacted for 8 h to obtain a light brown liquid. The liquid was washed three times with 500 mL of distilled water, and after rotary evaporation at 85 ° C for 30 min, 107.91 g of intermediate 2 was obtained with a yield of 59.44%.

[0116] S2, dissolve 107.91g of intermediate 2 in 2000mL of deionized water, adjust to pH=7 with 10% mass concentration of sodium hydroxide solution, add to a 5L four-necked flask and stir continuously, heat to 75°C, and slowly drip 400mL (0.08mol / L) of ammonium persulfate-water solution and 300mL (1.2mol / L) of dodecyl acrylate-isopropanol solution at the same time. After the dripping is completed, react at 75°C for 10h to obtain 3055.21g of colorless viscous liquid. Repeat washing with acetone 3 times, place the washed sample in an oven, and dry at 120°C to obtain 788.23g of light yellow powder, with a yield of 54.11%.

[0117] The synthesis path of this comparative example is as follows:

[0118]

[0119]

[0120] Among them, x=3, y=7, z=9.

[0121] The infrared spectrum of the perfluoropolyether anionic-nonionic surfactant prepared in this comparative example is as follows Fig.11 As shown, the nuclear magnetic hydrogen spectrum (deuterated methanol) is as follows Fig.12 shown.

[0122] The product properties of Example 1 to Example 4 and Comparative Example 1 to Comparative Example 5 are shown in Table 1:

[0123] Table 1

[0124] Solubility in water Surface tension in 0.5% aqueous solution (mN / m) Critical micelle concentration (wt%) Example 1 ≥27％ 19.4 0.056 Example 2 ≥15％ 18.2 0.060 Example 3 ≥5％ 17.7 0.071 Example 4 ≥1％ 16.8 0.092 Comparative Example 1 ＜2％ 23.4 0.054 Comparative Example 2 ≤0.5％ 18.3 0.066 Comparative Example 3 ≥35％ 28.7 0.081 Comparative Example 4 ≤5％ 30.4 0.023 Comparative Example 5 ≤10％ 28.9 0.048

[0125] Test method for solubility in water: Weigh the substance to be tested with an analytical balance, and add 1.00g, 2.00g, 5.00g, 10.00g, 15.00g, 20.00g, and 25.00g of the substance to be tested into a 100mL volumetric flask in turn. Add distilled water to the volumetric flask to make up the volume, and gently shake the volumetric flask to fully dissolve the substance to be tested. Take a constant temperature water bath, place the solution in a constant temperature water bath and maintain it at 25°C. Keep it warm for a period of time until the solution stabilizes, then take out the solution from the water bath and observe the state of the solution. The solution in the bottle is clear and uniform, and there is no solute residue at the bottom of the bottle, which is completely dissolved. The mass of solute added when it is completely dissolved is the solubility, and the solubility / 100g is the solubility of the solute in water.

[0126] Test method for surface tension and critical micelle concentration of aqueous solution: William plate method

[0127] The Williams plate method is a modified DuPont ring method. It uses a rectangular plate made of platinum as a probe, which is placed horizontally on the surface of the liquid and then slowly lifted until the probe is detached from the liquid surface. In this process, the liquid forms two films on both sides of the probe, exerting a downward force on the probe. This force is proportional to the surface tension of the liquid, and the surface tension can be calculated by measuring this force. The Williams plate method is suitable for measuring the surface tension of pure liquids or dilute solutions, and can also measure the interfacial tension between two immiscible liquids. Instrument used: Biolin ThetaLite optical contact angle meter.

[0128] From the data in Table 1, we can see that:

[0129] Compared with Comparative Examples 1 to 5, the introduction of lauryl ester and sodium benzenesulfonate fragments in Examples 1 to 4 increases solubility and dispersibility and reduces surface tension. If only sodium benzenesulfonate fragments are introduced, such as in Comparative Example 3, although the solubility in water is good, the surface tension in the aqueous solution is significantly increased; if only lauryl ester is introduced, such as in Comparative Example 4, the solubility in water is sharply reduced, and the surface tension in the aqueous solution is sharply increased; if R is not introduced f The solubility of the group, such as in Comparative Example 5, in water is sharply reduced, and the surface tension in the aqueous solution is sharply increased.

[0130] As a comparison of surfactant additives for tertiary oil recovery chemical flooding: the concentration of tertiary oil recovery chemical flooding surfactant added to the example and comparative example products is 0.1% to 1%. The results are shown in Table 2:

[0131] Table 2

[0132]

[0133] Oil-water interfacial tension, surface tension and critical micelle concentration test methods:

[0134] An aqueous solution of anionic nonionic surfactant with different mass fractions (0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%) was prepared, and the same volume of crude oil was added, and the instrument was tested at 25° C. Instrument used: Biolin Theta Lite optical contact angle measuring instrument.

[0135] From the data in Table 2, we can see that:

[0136] The perfluoropolyether anionic nonionic surfactants prepared in Examples 1 to 4 of the present invention have good ability to reduce oil-water interfacial tension; compared with Comparative Examples 1 and 2, the introduction of lauryl ester and sodium benzenesulfonate fragments increases solubility and dispersibility and reduces oil-water tension; compared with Comparative Examples 3 and 4, the introduction of lauryl ester reduces oil-water tension; compared with Comparative Example 5, after replacing the fluorine-containing group, the ability to reduce interfacial tension decreases sharply.

[0137] Thermal stability test of surfactants:

[0138] The surfactant was placed under reservoir conditions, and the interfacial tension was measured regularly. The thermal stability of the surfactant was investigated based on the change in interfacial tension. A 0.5% mass concentration aqueous surfactant solution was placed in a small autoclave, and taken out regularly to measure the interfacial tension between the surfactant and the corresponding oil well crude oil. The results are shown in Table 3:

[0139] Table 3

[0140]

[0141] From the data in Table 3, we can see that:

[0142] Affected by temperature, during the 60-day investigation period, the interfacial tension of the surfactant solution increased with time, the number of free ions decreased, the interfacial activity weakened, and the interfacial tension increased, but it was still below 40mN / m, indicating good stability and strong oil displacement ability.

[0143] The test results of the water contact angle between the solution and the natural core are shown in Table 4:

[0144] Table 4

[0145]

[0146]

[0147] From the data in Table 4, we can see that:

[0148] The perfluoropolyether anionic-nonionic surfactant prepared in Examples 1 to 4 is used as a surfactant additive for tertiary oil recovery. Compared with Comparative Example 2, the water contact angle between the product and the core is reduced to below 40° after wetting for 10 seconds, indicating that it has excellent wetting reversal. The product can significantly reduce the water contact angle on the rock surface, reduce the adhesion of oil droplets on the rock surface, and facilitate stripping and emulsification.

[0149] The salt tolerance test results are shown in Table 5 and Table 6:

[0150] Table 5

[0151] 2g / L NaCl 4g / L NaCl 6g / L NaCl 8g / L NaCl 10g / L NaCl Example 1 × × × × × Example 2 × × × × × Example 3 × × × × × Example 4 × × × × × Comparative Example 1 × × × × × Comparative Example 2 × × × × × Comparative Example 3 × √ √ √ √ Comparative Example 4 × × × × × Comparative Example 5 × × × × ×

[0152] Table 6

[0153]

[0154]

[0155] Note: In Table 5 and Table 6, “×” indicates that no new phase appears, and “√” indicates that a new phase appears

[0156] Salt resistance test: prepare a NaCl solution with a mineralization degree of 2-10 g / L and a CaCl2 solution with a mineralization degree of 10-100 g / L respectively, then use the two mineralized waters to prepare the example and comparative example solutions with a mass concentration of 0.3% respectively, and observe whether there are new phases such as precipitation and floccules after standing for 2 hours to test the solubility and salt resistance of the surfactant.

[0157] From the data in Table 5 and Table 6, we can see that:

[0158] The perfluoropolyether anionic nonionic surfactants prepared in Examples 1 to 4 can be rapidly dissolved in a NaCl solution with a mineralization of 100 g / L and a CaCl2 solution with a mineralization of 8 g / L, and no new phases such as precipitation and floccules are produced. There is no change after standing for 2 hours. The product has good salt resistance and has certain applicability in medium-high salt and high-high salt reservoirs.

[0159] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A perfluoropolyether anionic nonionic surfactant, characterized in that: Its structural formula is as follows: In the formula, R f It is a Y-type perfluoropolyether, the molecular weight of the Y-type perfluoropolyether is 300-2000 g / mol; x, y, and z are all integers of 1-20.

2. The method for preparing the perfluoropolyether anionic-nonionic surfactant according to claim 1, characterized in that: The following steps are involved: S1, subjecting Y-type perfluoropolyether alcohol to an esterification reaction with 3-butene-1-ol to obtain an intermediate 1; S2. The intermediate 1 prepared in step S1 is polymerized with sodium styrene sulfonate and dodecyl acrylate to obtain a perfluoropolyether anionic nonionic surfactant.

3. The preparation method according to claim 2, characterized in that: The specific process of step S1 is: The Y-type perfluoropolyether alcohol is mixed with solvent 1, and then catalyst 1 and acid binding agent are added, and then 3-butene-1-ol is added dropwise; after the addition is completed, the temperature is raised to the required temperature, and after the reaction is completed, the reaction is quenched and washed to obtain intermediate 1.

4. The preparation method according to claim 3, characterized in that: The solvent 1 is a non-fluorinated polar aprotic solvent; and the catalyst 1 is an organic weak acid.

5. The preparation method according to claim 3, characterized in that: In step S1, the reaction temperature is 70-100°C.

6. The preparation method according to claim 3, characterized in that: In step S1, the dropping speed of the 3-butene-1-ol is 8 to 20 mL / min.

7. The preparation method according to claim 2, characterized in that: The specific process of step S2 is: The intermediate 1 is dissolved in deionized water; the pH is adjusted to neutral, the catalyst 2 is added, and after stirring and heating to the required temperature, the sodium styrene sulfonate aqueous solution and the dodecyl acrylate-isopropanol solution are slowly added dropwise. After the addition is completed, the reaction and purification are carried out at a certain temperature to obtain a perfluoropolyether anionic-nonionic surfactant.

8. The preparation method according to claim 7, characterized in that: In step S2, the reaction temperature is 60-90°C; the catalyst 2 includes ammonium persulfate.

9. The preparation method according to claim 7, characterized in that: In step S2, the dropping speeds of the sodium styrene sulfonate aqueous solution and the lauryl acrylate-isopropanol solution are both 5-16 mL / min.

10. The use of the perfluoropolyether anionic nonionic surfactant in petroleum production as claimed in claim 1, characterized in that: Including applications in high-salt reservoirs.

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