Surfactants, methods of electrochemically synthesizing surfactants, and applications of surfactants

Abstract

This invention relates to the field of surfactant synthesis technology, specifically to a surfactant, a method for electrochemically synthesizing a surfactant, and the application of the surfactant. The surfactant comprises a non-polymeric molecule containing both hydrophilic and hydrophobic groups, and has a PDI of 1.05-1.15. The surfactant of this invention exhibits excellent thermal stability and salt resistance.

Description

Technical Field

[0001] This invention relates to the field of surfactant synthesis technology, specifically to a surfactant, a method for electrochemically synthesizing a surfactant, and the application of the surfactant. Background Technology

[0002] With the continued growth of global energy demand and the gradual depletion of conventional oil reservoirs, the development and utilization of heavy oil resources has increasingly become a focus of the petroleum industry. However, heavy oil development faces enormous technical challenges, mainly due to its extremely high viscosity and complex composition. These characteristics result in extremely poor fluidity of heavy oil under formation conditions, and traditional extraction techniques encounter numerous difficulties in developing heavy oil reservoirs.

[0003] Surfactants play a crucial role in heavy oil development, reducing oil-water interfacial tension, improving rock wettability, and enhancing oil displacement efficiency. However, existing surfactant synthesis technologies suffer from numerous problems: Complex synthetic routes: Conventional chemical synthesis methods usually require multiple reaction steps, which are cumbersome and difficult to separate and purify intermediate products, resulting in high overall synthesis difficulty and low product yield.

[0004] High production costs: Traditional synthesis processes are energy-intensive and material-intensive, especially in terms of catalysts and separation media, which seriously affect the economic viability of the products.

[0005] Environmental pollution: Traditional organic synthesis reactions generally involve the emission of "three wastes", especially when synthesizing surfactants containing nitrogen and sulfur and other heteroatoms, which does not conform to the development concept of green chemistry.

[0006] Product performance limitations: Existing synthesis methods make it difficult to precisely control the molecular structure of surfactants, resulting in products that cannot meet the stringent requirements of heavy oil development in terms of key performance indicators such as temperature resistance and salt resistance.

[0007] High dependence on raw materials: Traditional synthesis methods rely heavily on petroleum-based raw materials, and fluctuations in raw material prices have a significant impact on production costs, which is not conducive to the long-term stable development of the industry.

[0008] Therefore, developing a new, green, efficient, and low-cost method for synthesizing surfactants is of significant practical importance for promoting the efficient development of heavy oil resources. This new method should not only simplify the synthesis route and reduce production costs, but also minimize environmental pollution while improving product performance to meet the specific needs of heavy oil development.

[0009] Globally, numerous major chemical companies and research institutions are actively exploring green synthesis technologies for surfactants. For example, BASF in Germany has proposed a bio-based surfactant synthesis route based on renewable raw materials, Dow Chemical in the United States has developed a microreactor continuous flow synthesis technology, and Kao Corporation in Japan has made breakthrough progress in enzyme-catalyzed surfactant synthesis. These studies indicate that surfactant synthesis technology is at a critical juncture of innovation.

[0010] The development of novel surfactant synthesis methods is not only crucial for the efficient utilization of heavy oil resources but will also have a profound impact on the entire fine chemical industry. It may provide new insights into the design and synthesis of high-performance, multifunctional surfactants, driving technological advancements in related application areas such as enhanced oil recovery, environmental remediation, and biomedicine. Therefore, innovation in surfactant synthesis technology will have a far-reaching impact on global energy security, the sustainable development of the chemical industry, and the progress of related materials science. Summary of the Invention

[0011] The purpose of this invention is to overcome the problems of unstable performance of small molecule surfactant products, complex synthesis routes, high production costs, and serious environmental pollution in the prior art, and to provide a surfactant, a method for electrochemically synthesizing surfactant, and the application of surfactant, which has excellent stability.

[0012] To achieve the above objectives, the first aspect of the present invention provides a surfactant comprising a nonpolymeric molecule containing hydrophilic and hydrophobic groups, wherein the surfactant has a PDI of 1.05-1.15.

[0013] A second aspect of the present invention provides a method for electrochemically synthesizing surfactants, the method comprising: electrolyzing an electrolyte containing a hydrophobic precursor, a hydrophilic precursor, a supporting electrolyte, and a solvent using an electrode; wherein the electrode comprises a cathode and an anode, the anode being titanium coated with a coating material, and the cathode being stainless steel and / or carbon material, wherein the coating material comprises noble metal oxides and / or Group IVA metal oxides.

[0014] A third aspect of the present invention provides a surfactant prepared by the method described in the second aspect.

[0015] The fourth aspect of the present invention provides an application of a surfactant in the development of heavy oil, wherein the surfactant used in the application is the surfactant described in the first aspect and / or the surfactant described in the third aspect.

[0016] Through the above technical solution, the present invention has the following advantages: The surfactant of this invention has excellent thermal stability and salt resistance.

[0017] The surfactant synthesis method of this invention enables precise control of the molecular weight distribution of the product, which is far superior to traditional synthesis methods. Furthermore, the synthesis time is significantly reduced, greatly improving production efficiency and product yield. It is simple and efficient. Compared to traditional methods, this invention is not only applicable to petroleum-based raw materials but also successfully achieves surfactant synthesis using bio-based oil derivatives as raw materials, providing a new avenue for the development of bio-based surfactants. It reduces raw material costs and energy consumption, lowers equipment investment, and greatly enhances the economic viability of the product. This invention completely avoids the use of organic solvents, reducing solid waste generation and carbon emissions, achieving near-zero emission clean production.

[0018] The method of this invention can achieve a production scale of 100 L / h, laying the foundation for large-scale industrial production. During the scale-up process, all technical indicators remain stable, demonstrating good scalability.

[0019] In summary, the electrochemical synthesis method of this invention has achieved remarkable results in improving synthesis efficiency, reducing production costs, reducing environmental pollution, and enhancing product performance. It has opened up new avenues for the green manufacturing of surfactants and is of great significance for promoting technological progress in heavy oil development and upgrading the fine chemical industry. Attached Figure Description

[0020] Figure 1 This is a flow chart of the electrolysis reactor system of the present invention; Figure 2 This is a schematic diagram of the electrolytic reactor structure according to a preferred embodiment of the present invention; Figure 1 In the diagram, ① is the hydrophobic precursor tank, ② is the hydrophilic tank, ③ is the supporting electrolyte tank, ④ is the mixer, ⑤ is the preheater, ⑥ is the electrolytic reactor, ⑦ is the temperature controller, ⑧ is the pressure controller, ⑨ is the pH controller, ⑩ is the flow controller, ⑪ is the extractor, ⑫ is the distillation apparatus, ⑬ is the crystallizer, ⑭ is the filter, and ⑮ is the dryer; ac is the process of conveying raw materials to the mixer, d is the process of conveying the mixed liquid to the preheater, e is the process of the preheated liquid entering the reactor, f is the process of the reaction liquid entering the separation system, gj is the separation and purification process, and k is the control signal; Figure 2 In the diagram, ① is the feed inlet, ② is the electrode assembly area, ③ is the guide plate, ④ is the anode, ⑤ is the cathode, ⑥ is the temperature sensor, ⑦ is the pH sensor, ⑧ is the nitrogen inlet, and ⑨ is the discharge outlet. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The present invention provides a surfactant comprising a nonpolymeric molecule containing hydrophilic and hydrophobic groups, wherein the surfactant has a PDI of 1.05-1.15.

[0023] The surfactant of this invention has excellent thermal stability and salt resistance.

[0024] According to a preferred embodiment of the present invention, the PDI of the surfactant is 1.05-1.10.

[0025] According to a preferred embodiment of the present invention, the purity of the non-polymeric molecules in the surfactant is not less than 99%, preferably 99.5-99.9%. By adopting the aforementioned preferred embodiment, the thermal stability and salt resistance of the surfactant can be further improved.

[0026] In this invention, residual impurities in surfactants mainly include: unreacted raw materials, intermediates, and inorganic salt byproducts, the specific substances of which are usually determined by the type of raw materials.

[0027] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the selection of hydrophobic groups in non-polymeric molecules. Conventional hydrophobic groups in the art are all acceptable. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the hydrophobic groups in the non-polymeric molecules are selected from C10-C18 alkyl and / or aryl groups.

[0028] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the selection of hydrophilic groups in non-polymeric molecules. Conventional hydrophilic groups in the art are all acceptable. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the hydrophilic group in the non-polymeric molecule is selected from at least one of sulfonic acid groups, carboxylic acid groups, ether groups, and amine groups.

[0029] This invention provides a method for electrochemically synthesizing surfactants, the method comprising: electrolyzing an electrolyte containing a hydrophobic precursor, a hydrophilic precursor, a supporting electrolyte, and a solvent using an electrode; the electrode comprising a cathode and an anode, the anode being titanium coated with a coating material, and the cathode being stainless steel and / or carbon material, wherein the coating material comprises noble metal oxides and / or Group IVA metal oxides.

[0030] The surfactant synthesis method of this invention enables precise control of the molecular weight distribution of the product, which is far superior to traditional synthesis methods. Furthermore, the synthesis time is significantly reduced, greatly improving production efficiency and product yield. Compared to traditional methods, this invention is not only applicable to petroleum-based raw materials but also successfully achieves surfactant synthesis using bio-based oil derivatives as raw materials, providing a new avenue for the development of bio-based surfactants. This reduces raw material costs and energy consumption, lowers equipment investment, and greatly enhances the economic viability of the product. The method of this invention completely avoids the use of organic solvents, reducing solid waste generation and carbon emissions, achieving near-zero emission clean production.

[0031] According to a preferred embodiment of the present invention, the coating material includes at least one selected from RuO2, IrO2, and PbO2, preferably PbO2. By adopting the aforementioned preferred embodiment, the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0032] In this invention, there are no special requirements for the thickness of the coating on the titanium plate. According to a preferred embodiment of this invention, the coating thickness is 80-120 μm, and the active area must be completely covered, while a transition area can be left at the edge.

[0033] According to a preferred embodiment of the present invention, the stainless steel is selected from at least one of 316L stainless steel, 304 stainless steel, 310 stainless steel, and 317 stainless steel, preferably 316L stainless steel. By adopting the aforementioned preferred embodiment, the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0034] According to a preferred embodiment of the present invention, the carbon material is graphite.

[0035] According to a preferred embodiment of the present invention, the electrolysis conditions include a current density of 18-22 mA / cm², preferably 19.5-20.5 mA / cm². By adopting the aforementioned preferred scheme, a high product yield can be ensured, and the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0036] According to a preferred embodiment of the present invention, the electrolysis conditions include a voltage of 4.5-5.5 volts, preferably 4.9-5.1 volts. By adopting the aforementioned preferred scheme, a high product yield can be ensured, and the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0037] According to a preferred embodiment of the present invention, the electrolysis conditions include a temperature of 45-55 degrees Celsius, preferably 49-51 degrees Celsius. By adopting the aforementioned preferred scheme, a high product yield can be ensured, and the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0038] According to a preferred embodiment of the present invention, the electrolysis conditions include a time of 100-140 minutes, preferably 118-122 minutes. By adopting the aforementioned preferred scheme, a high product yield can be ensured, and the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0039] According to a preferred embodiment of the present invention, the pH value of the electrolyte is 7.0-8.0, preferably 7.4-7.6. By adopting the aforementioned preferred embodiment, a high product yield can be ensured, and the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0040] According to a preferred embodiment of the present invention, the hydrophobic group precursor is a C8-C18 alkyl halide.

[0041] According to a preferred embodiment of the present invention, the hydrophilic precursor is at least one selected from sulfonates, carboxylates, ether compounds, and amine compounds.

[0042] According to a preferred embodiment of the present invention, the supporting electrolyte is sodium sulfate.

[0043] According to a preferred embodiment of the present invention, the hydrophobic precursor is a C8-C18 alkyl bromide.

[0044] According to a preferred embodiment of the present invention, the hydrophilic precursor is sodium sulfite.

[0045] According to a preferred embodiment of the present invention, the molar ratio of the hydrophobic precursor, the hydrophilic precursor, and the supporting electrolyte in the electrolyte is (2-3):1:(0.04-0.06). By adopting the aforementioned preferred embodiment, the thermal stability and salt resistance of the electrosynthesized surfactant can be further improved.

[0046] In this invention, each raw material is fed in the form of a solution, wherein the concentration of the hydrophobic group precursor is 1.58-1.62 mol / L, the concentration of the hydrophilic group precursor is 1.08-1.12 mol / L, and the concentration of the supporting electrolyte is 0.215-0.225 mol / L.

[0047] According to a preferred embodiment of the present invention, the electrolysis includes: maintaining a continuous flow of inert gas during the electrolysis process, with a flow rate of 0.165-0.175 liters / minute.

[0048] According to a preferred embodiment of the present invention, the method further includes: purifying and separating the electrolyte obtained by electrolysis, wherein the purification and separation method includes: sequentially extracting, distilling, crystallizing, washing, drying, grinding and sieving the electrolyte.

[0049] In this invention, the extraction, distillation, crystallization, washing, drying, grinding, and sieving are all conventional methods in the art and will not be described in detail here. For example, hexane is used as the extractant; the vacuum distillation temperature is 40-50℃ and the pressure is 30-50 mmHg; the crystallization temperature is 0-5℃ and the time is 4-6 hours; anhydrous ethanol is used as the washing agent; and the drying is carried out under vacuum at 40-50℃ and 10-20 mmHg for 10-20 hours.

[0050] According to a preferred embodiment of the present invention, the electrolysis includes: performing electrolysis on the electrolyte 2-8 times in sequence.

[0051] The present invention provides a surfactant prepared by the method described above.

[0052] The surfactant prepared by the aforementioned method of the present invention has excellent thermal stability and salt resistance.

[0053] This invention provides an application of a surfactant in heavy oil development, wherein the surfactant used in this application is the surfactant described above.

[0054] The surfactant described above in this invention enables the efficient utilization of heavy oil resources.

[0055] like Figure 1 As shown, this invention provides a system for the electrochemical synthesis of surfactants. The system includes a raw material supply system, a reactor system, a control system, and a separation system. The raw material supply system, including raw material storage tanks and mixers, is capable of controlling the mixing and feeding ratio of each raw material component; The reactor system includes a preheater and an electrolysis reactor in sequence along the material flow direction, which preheat the mixture from the mixer before reacting; The control system can achieve real-time monitoring of temperature, pressure, pH and flow rate during the reaction; The separation system, along the material flow direction, includes an extractor, a distiller, a crystallizer, a filter, and a dryer in sequence, to complete the continuous separation and purification of the product.

[0056] like Figure 2The diagram shows a schematic of a preferred embodiment of an electrolytic reactor equipped with a single electrode assembly. The reactor has a feed inlet and outlet, and includes an inert gas protection system surrounding the electrode assembly and motor assembly. The electrode assembly adopts a parallel plate structure, with an electrode spacing of 4-6 cm, preferably adjustable within the range of 4.9-5.1 cm. A guide plate is provided between the electrodes. The electrolytic reactor is equipped with an in-situ monitoring system, including a temperature sensor, a pH sensor, and a pressure sensor.

[0057] In this invention, a single-electrode electrolytic reactor is used as an example to illustrate the advantages of the invention. However, it should be noted that the single-electrode electrolytic reactor is merely an exemplary illustration. The invention can also achieve multi-stage continuous electrolysis of the electrolyte by setting multiple electrode assemblies in one electrolytic reactor; or by setting multiple electrolytic reactors in series to achieve multi-stage continuous electrolysis of the electrolyte. When setting multiple electrode assemblies, each electrode assembly is equipped with an independent current control and monitoring device. The reaction control parameters are: electrolyte flow rate 2-3 L / min, single-layer residence time 10-50 min, and outlet conversion rate of each layer ≥80%. Multiple online monitoring points are set to track pH value, temperature, and conversion rate in real time.

[0058] The present invention will be described in detail below through examples. Unless otherwise specified, all raw materials are commercially available products.

[0059] In the following embodiments, the parameters were measured using the following methods: Product yield: Calculated by weight method, yield (%) = (actual yield / theoretical yield) × 100%.

[0060] Product purity: determined using a Waters Alliance e2695 high-performance liquid chromatograph. Column: Waters XBridge C18 column (4.6×250mm, 5μm); Mobile phase: methanol-water (80:20, v / v); Flow rate: 1.0 mL / min; Detection wavelength: 215 nm.

[0061] Thermal stability: The sample was sealed in a 10mL ampoule and stored in a DHG-9070A constant temperature drying oven (130±1℃) for 3 months. The mass loss was measured monthly.

[0062] Interfacial tension: Measured using a TX500C rotating drop interfacial tension meter at a temperature of 25±0.1℃ and a rotation speed of 4500rpm.

[0063] PDI: Measured using a Waters Alliance GPC 2000 system with tetrahydrofuran as the mobile phase, a flow rate of 1.0 mL / min, and a column temperature of 35 °C.

[0064] Raw material sources: Anode (PbO2 / Ti): Custom-made by the Institute of Electrochemistry, Chinese Academy of Sciences; Cathode (316L stainless steel): Shanghai Baosteel, model 316L-2B; Dodecyl bromide: Aladdin, purity 99.8%, item number D141457; Sodium sulfite: Sinopharm Group, analytical grade, item number 30168428; Sodium sulfate: Merck, analytical grade, item number 1.06649.

[0065] Example 1 use Figure 1 and Figure 2 The system and apparatus shown were used in the experiment, with a 316L stainless steel sheet (20cm × 10cm) as the cathode and a lead dioxide-coated (100μm thick) titanium plate (20cm × 10cm) as the anode. The electrodes were spaced 5cm apart and placed in a 50L polypropylene electrolytic cell. A magnetic stirrer was installed at the bottom, and the stirring speed was set to 100rpm.

[0066] Electrolytic synthesis: Mix 360 ml of dodecyl bromide (1.5 mol / L), 210 ml of sodium sulfite (1.0 mol / L), and 57 ml of sodium sulfate (0.2 mol / L), add deionized water to a total volume of 20 L, and stir at 400 rpm for 25 minutes. Transfer the solution to a 25 L plastic container and adjust the pH to 7.5. Filter through a 0.45 μm filter membrane. Preheat the prepared electrolyte to 50 °C in a preheater, then pass it into the electrolysis reactor. Connect a DC power supply, set the current density to 20 mA / cm², the voltage to 5 V, and the temperature to 50 °C. Purge with nitrogen gas at a flow rate of 0.15 L / min. Electrolyze for 120 minutes, taking samples every 30 minutes for monitoring. Stop electrolysis when the conversion rate reaches 97%.

[0067] Product separation and purification: The electrolyte was extracted three times with 22 L of n-hexane in a 45 L separatory funnel, each time for 18 minutes. The organic phase was collected, and the n-hexane was recovered by vacuum distillation (40 mmHg) at 45 °C. The residue was crystallized at 2 °C for 5 hours, and the crystals were collected by filtration and washed three times with 75 mL of pre-cooled anhydrous ethanol. The solution was then dried under vacuum at 45 °C and 15 mmHg for 14 hours.

[0068] Results: The yield of sodium dodecyl sulfate was 93%, and the purity of sodium dodecyl sulfate in the product was 99.5% (HPLC), with a PDI of 1.06. Thermal stability testing showed that the mass loss was less than 2% after 3 months at 130℃. Oil-water interfacial tension testing showed that the interfacial tension could be reduced to 0.007 mN / m under a salinity of 250,000 ppm.

[0069] Example 2 use Figure 1 and Figure 2 The system and apparatus shown were used in the experiment, with a 316L stainless steel sheet (21cm × 10.5cm) as the cathode and a lead dioxide-coated (105μm thick) titanium plate (21cm × 10.5cm) as the anode. The electrode spacing was 5.5cm, and the apparatus was placed in a 52L polypropylene electrolytic cell. A magnetic stirrer was installed at the bottom, and the stirring speed was set to 110rpm.

[0070] Electrolytic synthesis: Mix 384 ml of dodecyl bromide (1.6 mol / L), 231 g / ml of sodium sulfite (1.1 mol / L), and 63 ml of sodium sulfate (0.22 mol / L), add deionized water to a total volume of 20 L, and stir at 450 rpm for 25 minutes. Transfer the solution to a 25 L plastic container and adjust the pH to 7.2. Filter through a 0.45 μm filter membrane. Preheat the prepared electrolyte to 52 °C in a preheater, then pass it into the electrolysis reactor. Connect a DC power supply, set the current density to 21 mA / cm², the voltage to 5.2 V, and the temperature to 52 °C. Purge with nitrogen gas at a flow rate of 0.18 L / min. Electrolyze for 115 minutes, taking samples every 30 minutes for monitoring. Stop electrolysis when the conversion rate reaches 98%.

[0071] Product separation and purification: The electrolyte was extracted three times with 23 L of n-hexane in a 48 L separatory funnel, each time for 20 minutes. The organic phase was collected, and the n-hexane was recovered by vacuum distillation (35 mmHg) at 48 °C. The residue was crystallized at 1 °C for 5.5 hours, and the crystals were collected by filtration and washed twice with 80 mL of pre-cooled anhydrous ethanol. The solution was then dried under vacuum at 48 °C and 12 mmHg for 15 hours.

[0072] Results: The yield of sodium dodecyl sulfate was 94.5%, and the purity of sodium dodecyl sulfate in the product was 99.7% (HPLC), with a PDI of 1.05. Thermal stability testing showed a mass loss of less than 1.8% after 3 months at 135℃. Oil-water interfacial tension testing indicated that the interfacial tension could be reduced to 0.006 mN / m under a salinity of 270,000 ppm.

[0073] Example 3 use Figure 1 and Figure 2 The system and apparatus shown were used in the experiment, with a graphite felt (22cm × 11cm) as the cathode and a platinum-coated (110μm thick) titanium mesh (22cm × 11cm) as the anode. The electrode spacing was 5.2cm, and the apparatus was placed in a 55L polypropylene electrolytic cell. A magnetic stirrer was installed at the bottom, and the stirring speed was set to 115rpm.

[0074] Electrolytic synthesis: Mix 400 ml of hexadecyl chloride (1.6 mol / L), 245 ml of potassium sulfite (1.1 mol / L), and 65 ml of sodium chloride (0.22 mol / L), add deionized water to a total volume of 22 L, and stir at 420 rpm for 22 minutes. Transfer the solution to a 30 L plastic container and adjust the pH to 7.4. Filter through a 0.45 μm filter membrane. Preheat the prepared electrolyte to 51 °C in a preheater, then pass it into the electrolysis reactor. Connect a DC power supply, set the current density to 21 mA / cm², the voltage to 5.3 V, and the temperature to 51 °C. Purge with nitrogen gas at a flow rate of 0.17 L / min. Electrolyze for 118 minutes, taking samples every 30 minutes for monitoring. Stop electrolysis when the conversion rate reaches 96%.

[0075] (4) Product separation and purification: The separation and purification were carried out using the same method as in Example 1.

[0076] Results: The yield of potassium hexadecyl sulfate was 92%, the product purity was 99.3% (HPLC), and the PDI was 1.08. Thermal stability testing showed a mass loss of less than 2.2% after 3 months at 133℃. Oil-water interfacial tension testing indicated that the interfacial tension could be reduced to 0.008 mN / m under a salinity of 230,000 ppm.

[0077] Example 4 Similar to Example 1, except that the current density is set to 35 mA / cm² in the electrolytic synthesis step.

[0078] Results: The yield of sodium dodecyl sulfate was 85%, and the purity of sodium dodecyl sulfate in the product was 96.3% (HPLC), with a PDI of 1.13. Thermal stability testing showed a mass loss of 3.8% after 3 months at 130℃. Oil-water interfacial tension testing indicated that, under a salinity of 250,000 ppm, the interfacial tension could only be reduced to 0.012 mN / m.

[0079] Example 5 Same as Example 1, except that in the electrolytic synthesis step, dodecyl bromide is replaced with an equal volume of octadecyl bromide (1.5 mol / L).

[0080] Results: The yield of sodium octaalkyl sulfinate was 87%, with a product purity of 96.8% (HPLC) and a PDI of 1.12. Thermal stability testing showed a mass loss of 3.2% after 3 months at 130℃. Oil-water interfacial tension testing indicated that the interfacial tension could only be reduced to 0.011 mN / m under a salinity of 250,000 ppm.

[0081] Comparative Example 1 Similar to Example 1, except that a lead plate (20cm × 10cm) is used as the anode in the electrolytic reactor.

[0082] Results: The yield of sodium dodecyl sulfate was 82%, and the purity of sodium dodecyl sulfate in the product was 95.2% (HPLC), with a PDI of 1.17. Thermal stability testing showed a mass loss of 4.5% after 3 months at 130℃. Oil-water interfacial tension testing indicated that under a salinity of 250,000 ppm, the interfacial tension could only be reduced to 0.015 mN / m.

[0083] Comparative Example 2 Similar to Example 1, except that a graphite sheet (20cm×10cm) is used as the cathode in the electrolytic reactor.

[0084] Results: The yield of sodium dodecyl sulfate was 78%, with a product purity of 94.5% (HPLC) and a PDI of 1.18. Thermal stability testing showed a 5.2% mass loss after 3 months at 130℃. Oil-water interfacial tension testing indicated that, under a salinity of 250,000 ppm, the interfacial tension could only be reduced to 0.018 mN / m.

[0085] Comparative Example 3 (1) Preparation of reaction solution: In a 3L beaker, add 360g of dodecyl bromide (1.5mol / L), 210g of sodium sulfite (1.0mol / L), and 57g of sodium sulfate (0.2mol / L), along with 0.5% ammonium persulfate as an initiator. Add deionized water to a total volume of 20L, and stir at 400rpm for 25 minutes. Transfer the solution to a 25L plastic container and adjust the pH to 7.5 with 1mol / L NaOH solution. Filter through a 0.45μm filter membrane.

[0086] (2) Device assembly: Use a 5L four-necked flask equipped with a reflux condenser, and purge with nitrogen for protection. Install a magnetic stirrer at the bottom and set the stirring speed to 100 rpm.

[0087] (3) Reaction synthesis: Add 18 L of the prepared reaction solution, heat to 75°C, and maintain the temperature for 6 hours. Take samples hourly during this period. Stop the reaction when the conversion rate reaches 85%.

[0088] (4) Product separation and purification: The reaction solution was extracted three times with 22 L of n-hexane in a 45 L separatory funnel, each time for 18 minutes. The organic phase was collected, and the n-hexane was recovered by vacuum distillation (40 mmHg) at 45 °C. The residue was crystallized at 2 °C for 5 hours, and the crystals were collected by filtration and washed three times with 75 mL of pre-cooled anhydrous ethanol. The solution was then dried under vacuum at 45 °C and 15 mmHg for 14 hours.

[0089] Results: The yield of sodium dodecyl sulfate was 81%, with a product purity of 95.8% (HPLC) and a PDI of 1.35. Thermal stability testing showed a mass loss of 4.8% after 3 months at 130℃. Oil-water interfacial tension testing indicated that, under a salinity of 250,000 ppm, the interfacial tension could only be reduced to 0.016 mN / m.

[0090] Comparative Example 4 (1) Preparation of the synthesis solution: In a 3L beaker, add 360g of dodecyl alcohol (1.5mol / L) and 220g of chlorosulfonic acid (1.2mol / L). Add chloroform as a solvent to a total volume of 20L, and stir at 400rpm for 25 minutes. Transfer the solution to a 25L plastic container and neutralize to pH 7.5 with 1mol / L NaOH solution. Filter through a 0.45μm filter membrane.

[0091] (2) Device assembly: Use a 5L four-necked flask equipped with a reflux condenser. Attach a magnetic stirrer to the bottom and set the stirring speed to 100 rpm.

[0092] (3) Reaction synthesis: Add 18 L of the prepared reaction solution, cool to 5°C, and slowly add chlorosulfonic acid dropwise, controlling the temperature to not exceed 10°C. After the addition is complete, raise the temperature to 25°C and react for 4 hours. Take samples hourly during this period. Stop the reaction when the conversion rate reaches 83%.

[0093] (4) Product separation and purification: The reaction solution was extracted three times with 22 L of n-hexane in a 45 L separatory funnel, each time for 18 minutes. The organic phase was collected, and the solvent was recovered by vacuum distillation (40 mmHg) at 45 °C. The residue was crystallized at 2 °C for 5 hours, and the crystals were collected by filtration and washed three times with 75 mL of pre-cooled anhydrous ethanol. The solution was then dried under vacuum at 45 °C and 15 mmHg for 14 hours.

[0094] Results: The yield of sodium dodecyl sulfate was 80%, with a product purity of 94.8% (HPLC) and a PDI of 1.28. Thermal stability testing showed a mass loss of 4.5% after 3 months at 130℃. Oil-water interfacial tension testing indicated that, under a salinity of 250,000 ppm, the interfacial tension could only be reduced to 0.017 mN / m.

[0095] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A surfactant, characterized in that, The surfactant comprises a nonpolymeric molecule containing both hydrophilic and hydrophobic groups, and the surfactant has a PDI of 1.05-1.

15.

2. The surfactant according to claim 1, characterized in that, The surfactant has a PDI of 1.05-1.10; and / or The purity of the non-polymeric molecules in the surfactant is not less than 99%, preferably 99.5-99.9%.

3. The surfactant according to claim 1, characterized in that, The hydrophobic groups in the non-polymeric molecule are selected from C10-C18 alkyl and / or aryl groups; and / or The hydrophilic group in the non-polymeric molecule is selected from at least one of sulfonic acid group, carboxylic acid group, ether group and amine group.

4. A method for electrochemically synthesizing surfactants, characterized in that, The method includes: electrolyzing an electrolyte containing a hydrophobic precursor, a hydrophilic precursor, a supporting electrolyte, and a solvent using an electrode; the electrode includes a cathode and an anode, the anode being titanium coated with a coating material, and the cathode being stainless steel and / or carbon material, wherein the coating material includes noble metal oxides and / or Group IVA metal oxides.

5. The method according to claim 4, characterized in that, The coating material includes at least one of RuO2, IrO2, and PbO2; and / or The stainless steel is selected from at least one of 316L stainless steel, 304 stainless steel, 310 stainless steel and 317 stainless steel; The carbon material is graphite.

6. The method according to claim 4, characterized in that, The coating material is PbO2; and / or The stainless steel is 316L stainless steel.

7. The method according to claim 4, characterized in that, The conditions for electrolysis include: The current density is 18-22 mA / cm²; and / or The voltage is 4.5-5.5 volts; and / or Temperature: 45-55 degrees Celsius; and / or The duration is 100-140 minutes.

8. The method according to claim 4, characterized in that, The electrolyte has a pH value of 7.0-8.

0.

9. The method according to claim 4, characterized in that, The hydrophobic precursor is a C8-C18 alkyl halide; and / or The hydrophilic precursor is at least one of sulfonates, carboxylates, ethers, and amines; and / or The supporting electrolyte is sodium sulfate.

10. The method according to claim 9, characterized in that, The hydrophobic precursor is a C8-C18 alkyl bromide; and / or The hydrophilic group precursor is sodium sulfite.

11. The method according to claim 4, characterized in that, The molar ratio of the hydrophobic precursor, the hydrophilic precursor, and the supporting electrolyte in the electrolyte is (2-3):1:(0.04-0.06).

12. The method according to claim 4, wherein, The electrolysis includes maintaining a continuous flow of inert gas during the electrolysis process.

13. The method according to claim 4, wherein, The method further includes: purifying and separating the electrolyte obtained by electrolysis. The purification and separation method includes: the electrolyzed solution is sequentially extracted, distilled, crystallized, washed, dried, ground, and sieved.

14. The method according to claim 4, wherein, The electrolysis includes: performing electrolysis on the electrolyte 2-8 times in sequence.

15. A surfactant, characterized in that, The surfactant is prepared by the method described in any one of claims 4-14.

16. The application of a surfactant in heavy oil development, characterized in that, The surfactant used in this application is the surfactant described in any one of claims 1-3 and / or the surfactant described in claim 15.

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