Efficient compound quaternary ammonium salt reverse demulsifier and preparation method thereof

Abstract

The invention relates to an efficient compound quaternary ammonium salt reverse demulsifier and a preparation method thereof, and belongs to the technical field of oil field chemicals. According to the efficient compound quaternary ammonium salt reverse demulsifier, the nanoscale quaternary ammonium salt modified titanium dioxide and the network polymer quaternary ammonium salt are compounded, and the nanoscale quaternary ammonium salt modified titanium dioxide has a high specific area and can be integrated with the network polymer quaternary ammonium salt through intermolecular acting force, hydrogen bonds and the like to play a node role; the spreading degree of the network polymer quaternary ammonium salt is improved, so that the flexible network polymer quaternary ammonium salt with a longitudinal polyepichlorohydrin quaternary ammonium salt main chain and a transverse four-segment polyepichlorohydrin quaternary ammonium salt chain segment structure has relatively high distribution density and distribution uniformity of the quaternary ammonium salt at relatively low consumption and relatively low temperature; the transverse and longitudinal polyepichlorohydrin quaternary ammonium salt chain segments cooperate with each other to jointly play a demulsification role, so that the demulsification effect is improved, and oil products and suspended solids are effectively removed.

Description

Technical Field

[0001] The invention relates to a high-efficiency composite quaternary ammonium salt reverse demulsifier and a preparation method thereof, belonging to the technical field of oilfield chemicals. Background Art

[0002] With the exploitation of oilfield resources, most oilfields have entered the middle and late stages of high water content exploitation. The output of produced water from oil-in-water emulsions has increased, the water quality has changed, and the difficulty of treatment has increased. The water quality is becoming more and more complex, showing problems such as high mineralization, high oil emulsification, high small particle size suspended matter, high bacterial content, high corrosion rate, and low pH, low oil-water density difference, stable phase state, and great difficulty in oil-water separation, which limits the development of oil production technology. Therefore, the requirements for demulsification of produced water from oil-in-water emulsions are gradually increasing.

[0003] At present, the reverse demulsifiers used for demulsification of water-in-oil emulsions mainly include low molecular electrolytes, alcohols, surfactants, and high molecular polymers. Among them, polyquaternary ammonium salt demulsifiers have the advantages of good water solubility and fast diffusion rate, and have been widely studied. Chinese patent document CN112584910B discloses a hyperbranched quaternary ammonium salt reverse demulsifier prepared by aza-Michael addition reaction of polyamine (Michael donor) and activated olefin (Michael acceptor), but the quaternary ammonium salt chain segments in its structure are distributed in a disorderly manner, resulting in a general demulsification effect, and a better demulsification effect needs to be obtained at a higher temperature, which wastes energy and has a high processing cost. Summary of the invention

[0004] The invention aims to provide a high-efficiency composite quaternary ammonium salt reverse demulsifier and a preparation method thereof, so as to solve the problems of large addition amount and high demulsification temperature when the quaternary ammonium salt reverse demulsifier is used for demulsification of oil field produced water.

[0005] The invention provides a high-efficiency composite quaternary ammonium salt reverse demulsifier, which is composed of a polymer quaternary ammonium salt and a quaternary ammonium salt-modified nano titanium dioxide, wherein the mass ratio of the polymer quaternary ammonium salt to the quaternary ammonium salt-modified nano titanium dioxide is 18-20:1; the quaternary ammonium salt-modified nano titanium dioxide is prepared by reacting nano titanium dioxide and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride; The preparation method of the polymer quaternary ammonium salt is as follows: (1) reacting 2-hydroxy-1,3-propanediamine and bromopropane in a molar ratio of 1:2 to obtain a secondary amine compound; (2) reacting the secondary amino group in the secondary amine compound with di-tert-butyl dicarbonate to obtain an amine ester compound; (3) reacting the hydroxyl group in the amine ester compound with the terminal acyl chloride polyepichlorohydrin to obtain a polyepichlorohydrin bridged amine ester compound; the molar ratio of the amine ester compound to the terminal acyl chloride polyepichlorohydrin is 2:1, and the terminal acyl chloride polyepichlorohydrin is obtained by subjecting the product obtained by the reaction of polyepichlorohydrin diol and succinic anhydride to chlorination reaction; the polyepichlorohydrin diol is obtained by subjecting ethylene glycol and epichlorohydrin in a molar ratio of 0.2 to 0.3:1 to cationic ring-opening polymerization; (4) deprotecting the tert-butyloxycarbonyl group in the polyepichlorohydrin-bridged amine ester compound to obtain a polyepichlorohydrin-bridged secondary amine compound; (5) reacting the secondary amino group in the polyepichlorohydrin-bridged secondary amine compound with epichlorohydrin to obtain a polyepichlorohydrin-bridged four-arm chlorohydrin compound; then subjecting the polyepichlorohydrin-bridged four-arm chlorohydrin compound and epichlorohydrin to a cationic ring-opening polymerization to obtain a polyepichlorohydrin-bridged four-arm polyepichlorohydrin; in the cationic ring-opening polymerization, the molar ratio of epichlorohydrin to the polyepichlorohydrin-bridged secondary amine compound used to prepare the polyepichlorohydrin-bridged four-arm chlorohydrin compound is 0.1 to 0.2:1; (6) A tertiary amino group in the polyepichlorohydrin bridged four-arm polyepichlorohydrin is subjected to a quaternization reaction with an alkyl bromide to obtain an ammonium bromide bridged product; a chlorine atom in the ammonium bromide bridged product is subjected to a quaternization reaction with triethylamine to obtain a polymer quaternary ammonium salt; the alkyl bromide is dodecane bromide, undecane bromide, n-decane bromide, n-butane bromide, n-pentane bromide, n-hexane bromide, n-heptane bromide, n-octane bromide, or n-nonane bromide.

[0006] Preferably, in step (1) of the method for preparing a polymer quaternary ammonium salt, sodium hydroxide is used as a catalyst when 2-hydroxy-1,3-propylenediamine and bromopropane react, and the molar ratio of 2-hydroxy-1,3-propylenediamine, bromopropane and sodium hydroxide is 1:2:2.3-2.5; the reaction temperature of 2-hydroxy-1,3-propylenediamine and bromopropane is 60-70°C, and the reaction time is 2-3h.

[0007] Preferably, in step (2) of the method for preparing the polymer quaternary ammonium salt, the molar ratio of di-tert-butyl dicarbonate to the secondary amine compound is 2:1.

[0008] Preferably, in step (3) of the method for preparing the polymer quaternary ammonium salt, boron trifluoride etherate complex is used as a catalyst during the cationic ring-opening polymerization reaction, and the mass of the boron trifluoride etherate complex is 0.15-0.2% of the sum of the masses of ethylene glycol and epichlorohydrin; the temperature of the cationic ring-opening polymerization reaction is 0-5°C and the time is 3-4 hours; the temperature of the reaction of polyepichlorohydrin diol and succinic anhydride is 50-60°C and the time is 5-8 hours, and the molar ratio of polyepichlorohydrin diol to succinic anhydride is 1:2; and the acyl chloride reaction in step (3) is to mix the product obtained by the reaction of polyepichlorohydrin diol and succinic anhydride with dichlorothionyl in a mass ratio of 10:50-60 and then reflux for 24-30 hours.

[0009] Preferably, in step (4) of the method for preparing the polymer quaternary ammonium salt, the method for deprotecting the tert-butyloxycarbonyl group in the polyepichlorohydrin bridged amine ester compound is as follows: adding a dioxane solution of the polyepichlorohydrin bridged amine ester compound to a dioxane solution of hydrogen chloride, mixing and reacting for 4 to 5 hours, then adding sodium hydroxide, and adjusting the pH of the reaction solution to 7.5 to 8; the concentration of the dioxane solution of hydrogen chloride is 2 mol / L, and the mass ratio of the dioxane solution of the polyepichlorohydrin bridged amine ester compound to the dioxane solution of hydrogen chloride is 1:2 to 2.5.

[0010] Preferably, in step (5) of the method for preparing a polymer quaternary ammonium salt, when preparing a polyepichlorohydrin-bridged four-arm chlorohydrin compound, the molar ratio of the polyepichlorohydrin-bridged secondary amine compound to epichlorohydrin is 1:4-4.1, the reaction temperature is 58-65° C., and the reaction time is 5-7 h. In step (5), boron trifluoride etherate complex is used as a catalyst during the cationic ring-opening polymerization reaction, and the mass of the boron trifluoride etherate complex is 0.15-0.2% of the sum of the masses of the polyepichlorohydrin-bridged secondary amine compound and epichlorohydrin.

[0011] Preferably, in step (6) of the method for preparing a polymer quaternary ammonium salt, when the tertiary amino group in the polyepichlorohydrin-bridged four-arm polyepichlorohydrin and the alkyl bromide are subjected to a quaternization reaction, the molar ratio of the polyepichlorohydrin-bridged four-arm polyepichlorohydrin and the alkyl bromide is 1:4.5-5, the reaction temperature is 85-90°C, and the reaction time is 6-8h; the molar ratio of the chlorine element and triethylamine in the ammonium bromide bridging product is 1:1.1-1.3, and the temperature for the quaternization reaction of the chlorine atom in the ammonium bromide bridging product and the triethylamine is 85-90°C, and the reaction time is 6-8h.

[0012] Preferably, the mass ratio of the nano titanium dioxide and dimethyl octadecyl [3- (trimethoxysilyl) propyl] ammonium chloride is 1:4-5, and the reaction temperature of the nano titanium dioxide and dimethyl octadecyl [3- (trimethoxysilyl) propyl] ammonium chloride is 70-80° C. and the reaction time is 28-30 hours.

[0013] Preferably, the average particle size of the nano titanium dioxide is 25-40 nm.

[0014] The present invention also provides a method for preparing the above-mentioned high-efficiency composite quaternary ammonium salt reverse demulsifier, comprising the following steps: uniformly mixing the polymer quaternary ammonium salt and the quaternary ammonium salt modified nano titanium dioxide.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The high-efficiency composite quaternary ammonium salt reverse demulsifier of the present invention first connects four transverse sections of polyepichlorohydrin quaternary ammonium salt segments through a longitudinal polyepichlorohydrin quaternary ammonium salt main chain to form a dense polymeric quaternary ammonium salt molecule with dense quaternary ammonium salt long chain segments in both the longitudinal and transverse directions. The dense quaternary ammonium salt long chain segments in the longitudinal and transverse directions can form a regular flexible network structure through the fixation of chemical bonds and tension constraints, thereby avoiding the entanglement of the quaternary ammonium salt long chain segments, ensuring that the demulsifier can effectively improve the distribution density of the quaternary ammonium salt at a lower dosage and lower temperature. The uniformity of distribution is improved, and then the polymer quaternary ammonium salt and the quaternary ammonium salt modified nano titanium dioxide with a long fatty chain are compounded. The nano-scale quaternary ammonium salt modified titanium dioxide has a high specific area and can form a whole with the network polymer quaternary ammonium salt through intermolecular forces and hydrogen bonds, play a node role, and further improve the spreading degree of the network polymer quaternary ammonium salt, so that the horizontal and vertical polyepichlorohydrin quaternary ammonium salt chain segments of the polymer quaternary ammonium salt cooperate with each other to jointly play a demulsification effect, improve the demulsification effect, and effectively remove oil products and suspended matter.

[0016] (2) The present invention ensures that the molecular weight of the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment of the polymer quaternary ammonium salt is within an appropriate range by adjusting the molar ratio of ethylene glycol and epichlorohydrin, and ensures that the molecular weight of the polyepichlorohydrin quaternary ammonium salt segment grafted on the transverse four arms is within an appropriate range by adjusting the molar ratio of epichlorohydrin and the polyepichlorohydrin bridging secondary amine compound. This can prevent the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment from being entangled or the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment from overlapping, entangled and kinked in the wastewater, and ensures that the longitudinal main chain quaternary ammonium salt segment and the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment are stretched and opened, so that the longitudinal main chain quaternary ammonium salt segment and the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment cooperate with each other, thereby improving the demulsification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the H NMR spectrum of the polyepichlorohydrin bridged secondary amine compound prepared in the method for preparing a polymer quaternary ammonium salt in Example 1 of the present invention. DETAILED DESCRIPTION

[0018] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention.

[0019] The specific embodiments of the high-efficiency composite quaternary ammonium salt reverse demulsifier and its preparation method of the present invention are as follows: Example 1

[0020] The high-efficiency composite quaternary ammonium salt reverse demulsifier of this embodiment is composed of polymer quaternary ammonium salt and quaternary ammonium salt modified nano titanium dioxide, and the mass ratio of the polymer quaternary ammonium salt to the quaternary ammonium salt modified nano titanium dioxide is 18:1.

[0021] Wherein, the preparation method of polymer quaternary ammonium salt comprises the following steps: (1) 2-Hydroxy-1,3-propanediamine was added to a reaction kettle, and then bromopropane was added dropwise to the reaction kettle at 30°C. After the addition was completed, a 35% sodium hydroxide solution was added dropwise to the reaction kettle. After the addition was completed, the materials in the reaction kettle were heated to 60°C, stirred for reaction for 2 hours, cooled to room temperature, and the reaction product was extracted with dichloromethane. The organic phase obtained by extraction was then rotary evaporated to obtain a concentrate, and then the concentrate was purified by column chromatography (the eluent was composed of methanol and dichloromethane in a volume ratio of 1:20) to obtain a secondary amine compound. The molar ratio of 2-hydroxy-1,3-propanediamine, bromopropane and sodium hydroxide was 1:2:2.3. The structural formula of the secondary amine compound is as follows: .

[0022] (2) Add di-tert-butyl dicarbonate and ethyl acetate to a reactor and stir evenly to obtain a di-tert-butyl dicarbonate solution with a mass fraction of 45%; then cool the di-tert-butyl dicarbonate solution to -5°C, and under stirring, dropwise add a 40% mass fraction of a secondary amine compound in ethyl acetate solution to the reactor. After the dropwise addition is completed, the materials in the reactor are stirred and reacted at room temperature for 18 hours, and then water is added to quench the reaction, and then the reaction product is extracted with ethyl acetate, and the organic phase obtained by extraction is rotary evaporated to obtain a concentrate, and then the concentrate is purified by column chromatography (the eluent is composed of petroleum ether and ethyl acetate in a volume ratio of 3:1) to obtain an amine ester compound. Among them, the molar ratio of di-tert-butyl dicarbonate to the secondary amine compound is 2:1. The structural formula of the amine ester compound is as follows: .

[0023] (3) 40 parts by mass of 1,2-dichloroethane was added to the reactor, and nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, ethylene glycol and boron trifluoride ether complex catalyst were added to the reactor. After stirring, the materials in the reactor were cooled to 0°C. Then, under stirring conditions, 1,2-dichloroethane solution containing 50 parts by mass of epichlorohydrin (mass fraction of 60%) was added dropwise to the reactor. After the addition was completed, stirring was continued at 0°C for 3 hours. After the reaction was completed, water was added to the reactor for extraction, and the organic phase obtained by extraction was distilled under reduced pressure to obtain polyepichlorohydrin diol. Among them, the molar ratio of ethylene glycol to epichlorohydrin is 0.2:1, and the mass of the boron trifluoride ether complex catalyst is 0.15% of the sum of the masses of ethylene glycol and epichlorohydrin. The structural formula of polyepichlorohydrin diol is as follows: .

[0024] (4) Add polyepichlorohydrin diol and succinic anhydride into a reaction kettle, then add chloroform, heat to 50°C, stir and react for 5 hours, and remove the chloroform in the reaction kettle by reduced pressure distillation to obtain carboxyl-terminated polyepichlorohydrin; the molar ratio of polyepichlorohydrin diol to succinic anhydride is 1:2, and the mass of chloroform is 40% of the sum of the mass of polyepichlorohydrin diol and succinic anhydride.

[0025] Then, thionyl chloride was added to the reactor, heated to reflux, stirred and refluxed for 24 hours, and the excess thionyl chloride in the reactor was removed by vacuum distillation to obtain terminal acyl chloride polyepichlorohydrin; the mass ratio of carboxyl terminal polyepichlorohydrin to thionyl chloride was 10:50. The structural formula of terminal acyl chloride polyepichlorohydrin is as follows: .

[0026] (5) Add amine ester compounds and dichloromethane to the reactor, stir evenly, and obtain a 30% by mass amine ester compound solution; add terminal acyl chloride polyepichlorohydrin and dichloromethane to the reactor, stir evenly, and obtain a 20% by mass terminal acyl chloride polyepichlorohydrin solution; then, under stirring and 0°C, add the terminal acyl chloride polyepichlorohydrin solution dropwise to the amine ester compound solution. After the addition is completed, add triethylamine, continue to stir and react at room temperature for 12 hours, filter, and rotary evaporate the filtrate to obtain a polyepichlorohydrin bridged amine ester compound. The molar ratio of amine ester compounds, terminal acyl chloride polyepichlorohydrin and triethylamine is 2:1:1.2. The structural formula of the polyepichlorohydrin bridged amine ester compound is as follows: .

[0027] (6) Under stirring and 0°C, a 45% by mass fraction of a polyepichlorohydrin bridged amine ester compound in dioxane was added dropwise to a 2 mol / L solution of hydrogen chloride in dioxane. After the addition was completed, the reaction was continued to stir at room temperature for 4 h. Then, sodium hydroxide was added to adjust the pH of the reaction solution to 7.5. Then, water and ethyl acetate were added to the reaction solution for extraction. The organic phase obtained by extraction was distilled under reduced pressure and dried to obtain a polyepichlorohydrin bridged secondary amine compound (H NMR spectrum shown in FIG. Figure 1 As shown). The mass ratio of the dioxane solution of the polyepichlorohydrin bridged amine ester compound to the dioxane solution of hydrogen chloride is 1:2. The structural formula of the polyepichlorohydrin bridged secondary amine compound is as follows: .

[0028] (7) Add a polyepichlorohydrin-bridged secondary amine compound and 1,2-dichloroethane into a reaction kettle, stir evenly and heat to 58°C, then add epichlorohydrin dropwise into the reaction kettle under stirring conditions. After the addition is completed, continue stirring and reacting for 5 hours to generate a polyepichlorohydrin-bridged four-arm chlorohydrin compound in the reaction kettle; wherein the molar ratio of the polyepichlorohydrin-bridged secondary amine compound to epichlorohydrin is 1:4, and the mass of 1,2-dichloroethane is 50% of the sum of the masses of the polyepichlorohydrin-bridged secondary amine compound and epichlorohydrin.

[0029] Then, nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, a boron trifluoride ether complex catalyst was added to the reactor. After stirring evenly, the materials in the reactor were cooled to 0°C. Then, under stirring conditions, a 1,2-dichloroethane solution of epichlorohydrin (mass fraction of 60%) was added dropwise to the reactor. After the addition was completed, the reaction was continued to be stirred at 0°C for 3 hours. After the reaction was completed, water was added to the reactor for extraction. The organic phase obtained by the extraction was distilled under reduced pressure to obtain polyepichlorohydrin bridged four-arm polyepichlorohydrin. Among them, the molar ratio of epichlorohydrin and polyepichlorohydrin bridged secondary amine compound was 0.1:1, and the mass of the boron trifluoride ether complex catalyst was 0.15% of the sum of the mass of the polyepichlorohydrin bridged secondary amine compound and epichlorohydrin. The structural formula of polyepichlorohydrin bridged four-arm polyepichlorohydrin is as follows: .

[0030] (8) Add polyepichlorohydrin bridged four-arm polyepichlorohydrin and butanol into a reactor, stir evenly, then add alkyl bromide dropwise into the reactor at 85°C under stirring conditions, continue stirring and reflux reaction at 85°C for 6 hours after the addition is completed, then perform vacuum distillation to remove the solvent butanol and unreacted alkyl bromide to obtain an ammonium bromide bridged product. The molar ratio of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide is 1:4.5, the alkyl bromide is decane bromide, and the mass of butanol is 60% of the sum of the mass of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide.

[0031] (9) Add the ammonium bromide bridged product and butanol into a reactor, stir evenly, then dropwise add triethylamine into the reactor at 85°C under stirring conditions, continue stirring and reflux reaction at 85°C for 6 hours after the dropwise addition, then perform reduced pressure distillation to remove the solvent butanol and unreacted triethylamine, and obtain a polymer quaternary ammonium salt. The molar ratio of chlorine element to triethylamine in the ammonium bromide bridged product is 1:1.1, and the mass of butanol is 60% of the sum of the mass of the ammonium bromide bridged product and triethylamine.

[0032] The preparation method of quaternary ammonium salt modified nano titanium dioxide comprises the following steps: Nano titanium dioxide (average particle size of 25 nm) was dispersed in water to obtain a dispersion with a mass fraction of 0.7%, and then dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added to the dispersion, heated to 70°C, stirred for reaction for 30 hours, filtered, and the filter cake was washed with water and ethanol respectively, and dried to obtain quaternary ammonium salt modified nano titanium dioxide; the mass ratio of nano titanium dioxide to dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was 1:5.

[0033] Example 2

[0034] The high-efficiency composite quaternary ammonium salt reverse demulsifier of this embodiment is composed of polymer quaternary ammonium salt and quaternary ammonium salt modified nano titanium dioxide, and the mass ratio of the polymer quaternary ammonium salt to the quaternary ammonium salt modified nano titanium dioxide is 19:1.

[0035] Wherein, the preparation method of polymer quaternary ammonium salt comprises the following steps: (1) 2-Hydroxy-1,3-propanediamine was added to a reaction kettle, and then bromopropane was added dropwise to the reaction kettle at 32°C. After the addition was completed, a 38% sodium hydroxide solution was added dropwise to the reaction kettle. After the addition was completed, the materials in the reaction kettle were heated to 65°C, stirred for reaction for 2.5 hours, cooled to room temperature, and the reaction product was extracted with dichloromethane. The organic phase obtained by extraction was then rotary evaporated to obtain a concentrate, and then the concentrate was purified by column chromatography (the eluent was composed of methanol and dichloromethane in a volume ratio of 1:20) to obtain a secondary amine compound. The molar ratio of 2-hydroxy-1,3-propanediamine, bromopropane and sodium hydroxide was 1:2:2.4. The structural formula of the secondary amine compound is as follows: .

[0036] (2) Add di-tert-butyl dicarbonate and ethyl acetate to a reactor and stir evenly to obtain a di-tert-butyl dicarbonate solution with a mass fraction of 47%; then cool the di-tert-butyl dicarbonate solution to -3°C, and under stirring, dropwise add a 45% mass fraction of a secondary amine compound in ethyl acetate solution to the reactor. After the dropwise addition is completed, the materials in the reactor are stirred and reacted at room temperature for 20 hours, and then water is added to quench the reaction, and then the reaction product is extracted with ethyl acetate, and the organic phase obtained by extraction is rotary evaporated to obtain a concentrate, and then the concentrate is purified by column chromatography (the eluent is composed of petroleum ether and ethyl acetate in a volume ratio of 3:1) to obtain an amine ester compound. Among them, the molar ratio of di-tert-butyl dicarbonate to the secondary amine compound is 2:1. The structural formula of the amine ester compound is as follows: .

[0037] (3) 40 parts by mass of 1,2-dichloroethane was added to the reactor, and nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, ethylene glycol and boron trifluoride ether complex catalyst were added to the reactor. After stirring, the materials in the reactor were cooled to 2°C. Then, under stirring conditions, 1,2-dichloroethane solution containing 50 parts by mass of epichlorohydrin (mass fraction of 65%) was added dropwise to the reactor. After the addition was completed, stirring was continued at 2°C for 3.5 hours. After the reaction was completed, water was added to the reactor for extraction, and the organic phase obtained by extraction was distilled under reduced pressure to obtain polyepichlorohydrin diol. Among them, the molar ratio of ethylene glycol to epichlorohydrin is 0.25:1, and the mass of the boron trifluoride ether complex catalyst is 0.18% of the sum of the masses of ethylene glycol and epichlorohydrin. The structural formula of polyepichlorohydrin diol is as follows: .

[0038] (4) Add polyepichlorohydrin diol and succinic anhydride into a reaction kettle, then add chloroform, heat to 55°C, stir and react for 7 hours, and remove the chloroform in the reaction kettle by reduced pressure distillation to obtain carboxyl-terminated polyepichlorohydrin; the molar ratio of polyepichlorohydrin diol to succinic anhydride is 1:2, and the mass of chloroform is 45% of the sum of the mass of polyepichlorohydrin diol and succinic anhydride.

[0039] Then, thionyl chloride was added to the reactor, heated to reflux, stirred and refluxed for 26 hours, and the excess thionyl chloride in the reactor was removed by vacuum distillation to obtain terminal acyl chloride polyepichlorohydrin; the mass ratio of carboxyl terminal polyepichlorohydrin to thionyl chloride was 10:55. The structural formula of terminal acyl chloride polyepichlorohydrin is as follows: .

[0040] (5) Add amine ester compounds and dichloromethane to the reactor and stir evenly to obtain a 40% by mass amine ester compound solution; add terminal acyl chloride polyepichlorohydrin and dichloromethane to the reactor and stir evenly to obtain a 28% by mass terminal acyl chloride polyepichlorohydrin solution; then, under stirring and 3°C, add the terminal acyl chloride polyepichlorohydrin solution dropwise to the amine ester compound solution. After the addition is completed, add triethylamine, continue to stir and react at room temperature for 14 hours, filter, and rotary evaporate the filtrate to obtain a polyepichlorohydrin bridged amine ester compound. The molar ratio of amine ester compounds, terminal acyl chloride polyepichlorohydrin and triethylamine is 2:1:1.3. The structural formula of the polyepichlorohydrin bridged amine ester compound is as follows: .

[0041] (6) Under stirring and 2°C, a 48% by mass solution of polyepichlorohydrin bridged amine ester compound in dioxane was added dropwise to a solution of hydrogen chloride in dioxane (concentration 2 mol / L). After the addition was completed, the reaction was continued to stir at room temperature for 4.5 hours, and then sodium hydroxide was added to adjust the pH of the reaction solution to 7.5. Then, water and ethyl acetate were added to the reaction solution for extraction. The organic phase obtained by extraction was distilled under reduced pressure and dried to obtain a polyepichlorohydrin bridged secondary amine compound. The mass ratio of the polyepichlorohydrin bridged amine ester compound in dioxane to the hydrogen chloride in dioxane solution was 1:2.3. The structural formula of the polyepichlorohydrin bridged secondary amine compound is as follows: .

[0042] (7) Add a polyepichlorohydrin-bridged secondary amine compound and 1,2-dichloroethane into a reaction kettle, stir evenly and heat to 60°C, then add epichlorohydrin dropwise into the reaction kettle under stirring conditions. After the addition is completed, continue stirring and react for 6 hours to generate a polyepichlorohydrin-bridged four-arm chlorohydrin compound in the reaction kettle; wherein the molar ratio of the polyepichlorohydrin-bridged secondary amine compound to epichlorohydrin is 1:4.05, and the mass of 1,2-dichloroethane is 55% of the sum of the masses of the polyepichlorohydrin-bridged secondary amine compound and epichlorohydrin.

[0043] Then, nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, a boron trifluoride ether complex catalyst was added to the reactor. After stirring evenly, the temperature of the materials in the reactor was cooled to 3°C. Then, under stirring conditions, a 1,2-dichloroethane solution of epichlorohydrin (mass fraction of 65%) was added dropwise to the reactor. After the addition was completed, the reaction was continued to be stirred at 2°C for 3.5 hours. After the reaction was completed, water was added to the reactor for extraction. The organic phase obtained by the extraction was distilled under reduced pressure to obtain polyepichlorohydrin bridged four-arm polyepichlorohydrin. Among them, the molar ratio of epichlorohydrin and polyepichlorohydrin bridged secondary amine compound was 0.15:1, and the mass of the boron trifluoride ether complex catalyst was 0.18% of the sum of the mass of the polyepichlorohydrin bridged secondary amine compound and epichlorohydrin. The structural formula of polyepichlorohydrin bridged four-arm polyepichlorohydrin is as follows: .

[0044] (8) Add polyepichlorohydrin bridged four-arm polyepichlorohydrin and butanol into a reactor, stir evenly, then add alkyl bromide dropwise into the reactor at 88°C under stirring conditions, continue stirring and reflux reaction at 87°C for 7 hours, then perform vacuum distillation to remove the solvent butanol and unreacted alkyl bromide, and obtain an ammonium bromide bridged product. The molar ratio of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide is 1:4.7, the alkyl bromide is decane bromide, and the mass of butanol is 70% of the sum of the mass of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide.

[0045] (9) Add the ammonium bromide bridged product and butanol into a reactor, stir evenly, then dropwise add triethylamine into the reactor at 88°C under stirring conditions, continue stirring and reflux reaction at 88°C for 7 hours after the dropwise addition, then perform reduced pressure distillation to remove the solvent butanol and unreacted triethylamine, and obtain a polymer quaternary ammonium salt. The molar ratio of chlorine element to triethylamine in the ammonium bromide bridged product is 1:1.2, and the mass of butanol is 70% of the sum of the mass of the ammonium bromide bridged product and triethylamine.

[0046] The preparation method of quaternary ammonium salt modified nano titanium dioxide comprises the following steps: Nano titanium dioxide (average particle size of 30 nm) was dispersed in water to obtain a dispersion with a mass fraction of 0.8%, and then dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added to the dispersion, heated to 75°C, stirred for reaction for 29 hours, filtered, and the filter cake was washed with water and ethanol respectively, and dried to obtain quaternary ammonium salt modified nano titanium dioxide; the mass ratio of nano titanium dioxide to dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was 1:4.5.

[0047] Example 3

[0048] The high-efficiency composite quaternary ammonium salt reverse demulsifier of this embodiment is composed of polymer quaternary ammonium salt and quaternary ammonium salt modified nano titanium dioxide, and the mass ratio of the polymer quaternary ammonium salt to the quaternary ammonium salt modified nano titanium dioxide is 20:1.

[0049] Wherein, the preparation method of polymer quaternary ammonium salt comprises the following steps: (1) 2-Hydroxy-1,3-propanediamine was added to a reaction kettle, and then bromopropane was added dropwise to the reaction kettle at 35°C. After the addition was completed, a 40% sodium hydroxide solution was added dropwise to the reaction kettle. After the addition was completed, the materials in the reaction kettle were heated to 70°C, stirred for reaction for 3 hours, cooled to room temperature, and the reaction product was extracted with dichloromethane. The organic phase obtained by extraction was then rotary evaporated to obtain a concentrate, and then the concentrate was purified by column chromatography (the eluent was composed of methanol and dichloromethane in a volume ratio of 1:20) to obtain a secondary amine compound. The molar ratio of 2-hydroxy-1,3-propanediamine, bromopropane and sodium hydroxide was 1:2:2.5. The structural formula of the secondary amine compound is as follows: .

[0050] (2) Add di-tert-butyl dicarbonate and ethyl acetate to a reactor and stir evenly to obtain a di-tert-butyl dicarbonate solution with a mass fraction of 50%; then cool the di-tert-butyl dicarbonate solution to 0°C, and under stirring, dropwise add a 50% mass fraction ethyl acetate solution of a secondary amine compound to the reactor. After the dropwise addition is completed, the materials in the reactor are stirred and reacted at room temperature for 24 hours, and then water is added to quench the reaction, and then the reaction product is extracted with ethyl acetate, and the organic phase obtained by extraction is rotary evaporated to obtain a concentrate, and then the concentrate is purified by column chromatography (the eluent is composed of petroleum ether and ethyl acetate in a volume ratio of 3:1) to obtain an amine ester compound. Among them, the molar ratio of di-tert-butyl dicarbonate to the secondary amine compound is 2:1. The structural formula of the amine ester compound is as follows: .

[0051] (3) 40 parts by mass of 1,2-dichloroethane was added to the reactor, and nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, ethylene glycol and boron trifluoride ether complex catalyst were added to the reactor. After stirring, the materials in the reactor were cooled to 5°C. Then, under stirring conditions, 1,2-dichloroethane solution containing 50 parts by mass of epichlorohydrin (mass fraction of 70%) was added dropwise to the reactor. After the addition was completed, stirring was continued at 5°C for 4 hours. After the reaction was completed, water was added to the reactor for extraction, and the organic phase obtained by extraction was distilled under reduced pressure to obtain polyepichlorohydrin diol. Among them, the molar ratio of ethylene glycol to epichlorohydrin is 0.3:1, and the mass of the boron trifluoride ether complex catalyst is 0.2% of the sum of the masses of ethylene glycol and epichlorohydrin. The structural formula of polyepichlorohydrin diol is as follows: .

[0052] (4) Add polyepichlorohydrin diol and succinic anhydride into a reaction kettle, then add chloroform, heat to 60°C, stir and react for 8 hours, and remove the chloroform in the reaction kettle by reduced pressure distillation to obtain carboxyl-terminated polyepichlorohydrin; the molar ratio of polyepichlorohydrin diol to succinic anhydride is 1:2, and the mass of chloroform is 50% of the sum of the mass of polyepichlorohydrin diol and succinic anhydride.

[0053] Then, thionyl chloride was added to the reactor, heated to reflux, stirred and refluxed for 30 hours, and the excess thionyl chloride in the reactor was removed by vacuum distillation to obtain terminal acyl chloride polyepichlorohydrin; the mass ratio of carboxyl terminal polyepichlorohydrin to thionyl chloride was 10:60. The structural formula of terminal acyl chloride polyepichlorohydrin is as follows: .

[0054] (5) Add amine ester compounds and dichloromethane to the reactor, stir evenly, and obtain a 45% by mass amine ester compound solution; add terminal acyl chloride polyepichlorohydrin and dichloromethane to the reactor, stir evenly, and obtain a 35% by mass terminal acyl chloride polyepichlorohydrin solution; then, under stirring and 5°C, add the terminal acyl chloride polyepichlorohydrin solution dropwise to the amine ester compound solution. After the addition is completed, add triethylamine, continue to stir and react at room temperature for 15 hours, filter, and rotary evaporate the filtrate to obtain a polyepichlorohydrin bridged amine ester compound. The molar ratio of amine ester compounds, terminal acyl chloride polyepichlorohydrin and triethylamine is 2:1:1.4. The structural formula of the polyepichlorohydrin bridged amine ester compound is as follows: .

[0055] (6) Under stirring and 5°C, a 50% by mass solution of polyepichlorohydrin bridged amine ester compound in dioxane was added dropwise to a solution of hydrogen chloride in dioxane (concentration of 2 mol / L). After the addition was completed, the reaction was continued to stir at room temperature for 5 hours, and then sodium hydroxide was added to adjust the pH of the reaction solution to 8. Then water and ethyl acetate were added to the reaction solution for extraction. The organic phase obtained by extraction was distilled under reduced pressure and dried to obtain a polyepichlorohydrin bridged secondary amine compound. The mass ratio of the polyepichlorohydrin bridged amine ester compound in dioxane to the hydrogen chloride in dioxane solution was 1:2.5. The structural formula of the polyepichlorohydrin bridged secondary amine compound is as follows: .

[0056] (7) Add a polyepichlorohydrin-bridged secondary amine compound and 1,2-dichloroethane into a reaction kettle, stir evenly and heat to 65°C, then add epichlorohydrin dropwise into the reaction kettle under stirring conditions. After the addition is completed, continue stirring and reacting for 7 hours to generate a polyepichlorohydrin-bridged four-arm chlorohydrin compound in the reaction kettle; wherein the molar ratio of the polyepichlorohydrin-bridged secondary amine compound to epichlorohydrin is 1:4.1, and the mass of 1,2-dichloroethane is 60% of the sum of the masses of the polyepichlorohydrin-bridged secondary amine compound and epichlorohydrin.

[0057] Then, nitrogen was introduced into the reactor. After the air in the reactor was completely replaced, a boron trifluoride ether complex catalyst was added to the reactor. After stirring evenly, the temperature of the materials in the reactor was lowered to 5°C. Then, under stirring conditions, a 1,2-dichloroethane solution of epichlorohydrin (mass fraction of 70%) was added dropwise to the reactor. After the addition was completed, the reaction was continued to be stirred at 5°C for 4 hours. After the reaction was completed, water was added to the reactor for extraction. The organic phase obtained by the extraction was distilled under reduced pressure to obtain polyepichlorohydrin bridged four-arm polyepichlorohydrin. Among them, the molar ratio of epichlorohydrin and polyepichlorohydrin bridged secondary amine compound was 0.2:1, and the mass of the boron trifluoride ether complex catalyst was 0.2% of the sum of the mass of the polyepichlorohydrin bridged secondary amine compound and epichlorohydrin. The structural formula of polyepichlorohydrin bridged four-arm polyepichlorohydrin is as follows: .

[0058] (8) Add polyepichlorohydrin bridged four-arm polyepichlorohydrin and butanol into a reactor, stir evenly, then add alkyl bromide dropwise into the reactor at 90°C under stirring conditions, continue stirring and reflux reaction at 90°C for 8 hours after the addition is completed, then perform vacuum distillation to remove the solvent butanol and unreacted alkyl bromide to obtain an ammonium bromide bridged product. The molar ratio of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide is 1:5, the alkyl bromide is decane bromide, and the mass of butanol is 80% of the sum of the mass of polyepichlorohydrin bridged four-arm polyepichlorohydrin and alkyl bromide.

[0059] (9) Add the ammonium bromide bridging product and butanol into a reactor, stir evenly, then dropwise add triethylamine into the reactor at 90°C under stirring conditions, continue stirring and reflux reaction at 90°C for 8 hours after the dropwise addition, then perform reduced pressure distillation to remove the solvent butanol and unreacted triethylamine, and obtain a polymer quaternary ammonium salt. The molar ratio of chlorine element to triethylamine in the ammonium bromide bridging product is 1:1.3, and the mass of butanol is 80% of the sum of the mass of the ammonium bromide bridging product and triethylamine.

[0060] The preparation method of quaternary ammonium salt modified nano titanium dioxide comprises the following steps: Nano titanium dioxide (average particle size of 40 nm) was dispersed in water to obtain a dispersion with a mass fraction of 1%, and then dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added to the dispersion, heated to 80°C, stirred for reaction for 28 hours, filtered, and the filter cake was washed with water and ethanol respectively, and dried to obtain quaternary ammonium salt modified nano titanium dioxide; the mass ratio of nano titanium dioxide to dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was 1:4.

[0061] Example 4

[0062] The only difference between the efficient composite quaternary ammonium salt reverse demulsifier of this embodiment and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the bromoalkane in step (8) of the method for preparing the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this embodiment is n-butyl bromide.

[0063] Example 5

[0064] The only difference between the efficient composite quaternary ammonium salt reverse demulsifier of this embodiment and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the bromoalkane in step (8) of the method for preparing the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this embodiment is dodecane bromide.

[0065] The preparation method of the high-efficiency composite quaternary ammonium salt reverse demulsifier of Example 1-5 is as follows: the polymer quaternary ammonium salt and the quaternary ammonium salt modified nano titanium dioxide are stirred evenly to obtain.

[0066] Comparative Example 1 The difference between the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the preparation method of the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example comprises the following steps: (1) 2-Hydroxy-1,3-propanediamine was added to a reaction kettle, and then bromopropane was added dropwise to the reaction kettle at 30°C. After the addition was completed, a 35% by mass sodium hydroxide solution was added dropwise to the reaction kettle. After the addition was completed, the materials in the reaction kettle were heated to 60°C, stirred for reaction for 2 hours, cooled to room temperature, and the reaction product was extracted with dichloromethane. The organic phase obtained by extraction was then subjected to rotary evaporation to obtain a concentrate, and then the concentrate was purified by column chromatography (the eluent was composed of methanol and dichloromethane in a volume ratio of 1:20) to obtain a secondary amine compound. The molar ratio of 2-hydroxy-1,3-propanediamine, bromopropane and sodium hydroxide was 1:2:2.3.

[0067] (2) A secondary amine compound and 1,2-dichloroethane are added to a reaction kettle, stirred evenly and heated to 58°C, and then epichlorohydrin is added dropwise to the reaction kettle under stirring. After the addition is completed, the stirring reaction is continued for 5 hours to generate a chlorohydrin compound in the reaction kettle; wherein the molar ratio of the secondary amine compound to epichlorohydrin is 1:2, and the mass of 1,2-dichloroethane is 50% of the sum of the masses of the secondary amine compound and epichlorohydrin.

[0068] Then, nitrogen is introduced into the reactor. After the air in the reactor is completely replaced, a boron trifluoride ether complex catalyst is added into the reactor. After stirring evenly, the materials in the reactor are cooled to 0°C. Then, under stirring conditions, a 1,2-dichloroethane solution of epichlorohydrin (mass fraction of 60%) is added dropwise into the reactor. After the addition is completed, stirring and reacting is continued at 0°C for 3 hours. After the reaction is completed, water is added into the reactor for extraction, and the organic phase obtained by extraction is distilled under reduced pressure to obtain polyepichlorohydrin. Among them, the molar ratio of epichlorohydrin to the secondary amine compound is 0.1:1, and the mass of the boron trifluoride ether complex catalyst is 0.15% of the sum of the mass of the secondary amine compound and epichlorohydrin.

[0069] (3) Add polyepichlorohydrin and butanol into a reaction kettle, stir evenly, then add alkyl bromide dropwise into the reaction kettle at 85°C under stirring conditions, continue stirring and reflux reaction at 85°C for 6 hours after the addition is completed, then perform vacuum distillation to remove the solvent butanol and unreacted alkyl bromide to obtain ammonium bromide product. The molar ratio of polyepichlorohydrin to alkyl bromide is 1:2.5, the alkyl bromide is n-decane bromide, and the mass of butanol is 60% of the sum of the masses of polyepichlorohydrin and alkyl bromide.

[0070] (4) Add the ammonium bromide product and butanol into a reactor, stir evenly, then dropwise add triethylamine into the reactor at 85°C under stirring conditions, continue stirring and reflux reaction at 85°C for 6 hours, then perform reduced pressure distillation to remove the solvent butanol and unreacted triethylamine, and obtain a polymer quaternary ammonium salt. The molar ratio of chlorine element to triethylamine in the ammonium bromide product is 1:1.1, and the mass of butanol is 60% of the sum of the mass of the ammonium bromide product and triethylamine.

[0071] Comparative Example 2 The difference between the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the preparation method of the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example comprises the following steps: (1) 40 parts by mass of 1,2-dichloroethane are added to a reactor, and nitrogen is introduced into the reactor. After the air in the reactor is completely replaced, ethylene glycol and boron trifluoride ether complex catalyst are added to the reactor, and the temperature of the materials in the reactor is lowered to 0°C after stirring. Then, under stirring conditions, 1,2-dichloroethane solution containing 50 parts by mass of epichlorohydrin (mass fraction of 60%) is added dropwise to the reactor. After the addition is completed, stirring is continued at 0°C for 3 hours. After the reaction is completed, water is added to the reactor for extraction, and the organic phase obtained by extraction is distilled under reduced pressure to obtain polyepichlorohydrin diol. The molar ratio of ethylene glycol to epichlorohydrin is 0.2:1, and the mass of the boron trifluoride ether complex catalyst is 0.15% of the sum of the masses of ethylene glycol and epichlorohydrin.

[0072] (2) Add polyepichlorohydrin diol and butanol into a reaction kettle, stir evenly, then add triethylamine dropwise into the reaction kettle at 85°C under stirring conditions, continue stirring and reflux reaction at 85°C for 6 hours after the addition is completed, then perform reduced pressure distillation to remove the solvent butanol and unreacted triethylamine to obtain a polymer quaternary ammonium salt. The molar ratio of chlorine element to triethylamine in polyepichlorohydrin diol is 1:1.1, and the mass of butanol is 60% of the sum of the mass of polyepichlorohydrin diol and triethylamine.

[0073] Comparative Example 3 The only difference between the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency composite quaternary ammonium salt reverse demulsifier of Example 1 is that the molar ratio of ethylene glycol to epichlorohydrin in step (3) of the preparation method of the polymer quaternary ammonium salt in the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example is 0.1:1.

[0074] Comparative Example 4 The only difference between the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency composite quaternary ammonium salt reverse demulsifier of Example 1 is that the molar ratio of ethylene glycol to epichlorohydrin in step (3) of the preparation method of the polymer quaternary ammonium salt in the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example is 0.4:1.

[0075] Comparative Example 5 The only difference between the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency composite quaternary ammonium salt reverse demulsifier of Example 1 is that in step (7) of the preparation method of the polymer quaternary ammonium salt in the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example, the molar ratio of epichlorohydrin and polyepichlorohydrin bridged secondary amine compound is adjusted from 0.1:1 to 0.05:1.

[0076] Comparative Example 6 The only difference between the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency composite quaternary ammonium salt reverse demulsifier of Example 1 is that in step (7) of the preparation method of the polymer quaternary ammonium salt in the high-efficiency composite quaternary ammonium salt reverse demulsifier of this comparative example, the molar ratio of epichlorohydrin and polyepichlorohydrin bridged secondary amine compound is adjusted from 0.1:1 to 0.3:1.

[0077] Comparative Example 7 The only difference between the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the preparation method of the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example comprises the following steps: the polymer quaternary ammonium salt prepared in comparative example 1 and the polymer quaternary ammonium salt prepared in comparative example 2 are stirred uniformly in a mass ratio of 4:1 to obtain the polymer quaternary ammonium salt.

[0078] Comparative Example 8 The only difference between the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that the preparation method of the polymer quaternary ammonium salt in the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example comprises the following steps: adding 70 g of (3-acrylamidopropyl)trimethylammonium chloride and 20 g of water into a reactor, then dropping 10 g of pentaethylenehexamine into the reactor under room temperature and stirring conditions, then stirring the reaction at 80°C for 12 hours, removing water by distillation under reduced pressure, and obtaining the efficient composite quaternary ammonium salt reverse demulsifier after drying.

[0079] Comparative Example 9 The only difference between the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example and the efficient composite quaternary ammonium salt reverse demulsifier of Example 1 is that in the preparation method of the quaternary ammonium salt modified nano titanium dioxide in the efficient composite quaternary ammonium salt reverse demulsifier of this comparative example, dimethyloctadecyl [3- (trimethoxysilyl) propyl] ammonium chloride is replaced by trimethyl [3- (trimethoxysilyl) propyl] ammonium chloride.

[0080] Comparative Example 10 The only difference between the high-efficiency compound quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency compound quaternary ammonium salt reverse demulsifier of Example 1 is that the amount of quaternary ammonium salt modified nano titanium dioxide in the high-efficiency compound quaternary ammonium salt reverse demulsifier of this comparative example is 0.

[0081] Comparative Example 11 The only difference between the high-efficiency compounded quaternary ammonium salt reverse demulsifier of this comparative example and the high-efficiency compounded quaternary ammonium salt reverse demulsifier of Example 1 is that the amount of polymer quaternary ammonium salt in the high-efficiency compounded quaternary ammonium salt reverse demulsifier of this comparative example is 0.

[0082] Effect example In order to investigate the comprehensive performance of the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared in each embodiment and comparative example, the simulated oily wastewater was added to a conical flask, and the experimental temperature (the experimental temperature was 30°C or 80°C) was kept constant for 30 minutes, and then the high-efficiency composite quaternary ammonium salt reverse demulsifier (dosage was 50 mg / L) was added to the conical flask, magnetically stirred for 3 minutes, and left to stand for 45 minutes, and the lower layer of clear liquid was taken, and the oil concentration and suspended matter concentration of the clear liquid were tested according to the provisions of the standard SY / T5329-1994 "Recommended Indicators and Analysis Methods for Water Quality of Clastic Reservoirs". Then, according to the oil concentration and suspended matter concentration of the simulated oily wastewater, the oil removal rate and suspended matter removal rate in the demulsification process were calculated, and the oil removal rate = (the oil concentration of the simulated oily wastewater-the oil concentration of the clear liquid) / the oil concentration of the simulated oily wastewater, and the suspended matter removal rate = (the suspended matter concentration of the simulated oily wastewater-the suspended matter concentration of the clear liquid) / the suspended matter concentration of the simulated oily wastewater. Among them, the oil concentration of simulated oily wastewater is 700 mg / L, and the suspended matter concentration is 175 mg / L.

[0083] The oil removal rate and suspended solids removal rate corresponding to the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared in each embodiment and comparative example are shown in Table 1.

[0084] Table 1 Oil removal rate and suspended solids removal rate corresponding to the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared in each embodiment and comparative example

[0085] It can be seen from the test results of Table 1 that when the addition amount of the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared by the present invention in oily sewage is 50 mg / L, the oil removal rate and the suspended solid removal rate in sewage at 80° C. are both more than 89%, and the oil removal rate and the suspended solid removal rate in sewage at 30° C. are both more than 81%. Among them, the oil removal rate and the suspended solid removal rate corresponding to the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared by Examples 1-3 at 80° C. are both more than 93%, and the oil removal rate and the suspended solid removal rate corresponding to 30° C. are both more than 90%, indicating that the high-efficiency composite quaternary ammonium salt reverse demulsifier prepared by the present invention has a good removal rate for oil products and suspended solids in sewage at both low and high temperatures. The above experimental results show that the high-efficiency composite quaternary ammonium salt reverse demulsifier of the present invention is compounded by nano-scale quaternary ammonium salt modified titanium dioxide and network polymer quaternary ammonium salt. The nano-scale quaternary ammonium salt modified titanium dioxide has a high specific area and can be integrated with the network polymer quaternary ammonium salt through intermolecular forces and hydrogen bonds, etc., to play a node role, improve the spreading degree of the network polymer quaternary ammonium salt, so that the flexible network polymer quaternary ammonium salt with a longitudinal polyepichlorohydrin quaternary ammonium salt main chain and a transverse four-segment polyepichlorohydrin quaternary ammonium salt segment structure has a higher quaternary ammonium salt distribution density and distribution uniformity at a lower dosage and a lower temperature. The transverse and longitudinal polyepichlorohydrin quaternary ammonium salt segments cooperate with each other to jointly play a demulsifying effect, improve the demulsifying effect, and effectively remove oil products and suspended matter.

[0086] As shown in Example 1 and Example 4-5, when the bromohydrocarbon that tertiary amine is carried out quaternization is replaced with the longer dodecane bromide of carbon chain to prepare polymer quaternary ammonium salt, the quaternary ammonium salt segment length of the transverse four-arm of the polymer quaternary ammonium salt of preparation can cover lipophilic butyrate esterified segment, affects the lipophilicity of the longitudinal main chain poly-epichlorohydrin quaternary ammonium salt segment of demulsifier, causes demulsification effect variation.When the bromohydrocarbon that tertiary amine is carried out quaternization is replaced with the shorter n-butyl bromide of carbon chain, the hydrophobicity variation of the quaternary ammonium salt segment of the transverse four-arm of the polymer quaternary ammonium salt of preparation, affects the lipophilicity of the transverse four-arm poly-epichlorohydrin quaternary ammonium salt segment of demulsifier, causes demulsification effect variation.Therefore, in order to effectively improve the demulsification effect at low and high temperatures, it is necessary to make the bromohydrocarbon fatty chain remain on suitable length.

[0087] It can be seen from Example 1, Comparative Examples 1-2 and Comparative Example 7 that when the longitudinal main chain polyepichlorohydrin quaternary ammonium salt demulsifier prepared in Comparative Example 1 and the polyepichlorohydrin quaternary ammonium salt segment prepared in Comparative Example 2 are simply compounded by physical mixing, due to the lack of chemical bond fixation and tension constraint, the two cannot form a regular network structure, and will be entangled and twisted together in the wastewater, reducing the uniformity and distribution range of the quaternary ammonium salt, resulting in a demulsification effect, and the demulsification effect after the two are mixed is worse than the demulsification effect of using one of the two alone.

[0088] As shown in Example 1 and Comparative Examples 3-4, when the molecular weight of the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment is changed by adjusting the mol ratio of ethylene glycol and epichlorohydrin, when the molecular weight of the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment is too large, it is easily entangled with a kink in waste water, which is unfavorable for the stretching and opening of the longitudinal main chain quaternary ammonium salt segment, and then affects the demulsification effect; when the molecular weight of the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment is too small, the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment cannot effectively stretch, causing overlapping winding kink, which is unfavorable for the stretching and opening of the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment, and then affects the demulsification effect. Therefore, in order to cooperate with the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment, the mol ratio of ethylene glycol and epichlorohydrin during the preparation of the longitudinal main chain polyepichlorohydrin quaternary ammonium salt segment needs to be controlled in a suitable range.

[0089] It can be seen from Example 1 and Comparative Examples 5-6 that when the molecular weight of the polyepichlorohydrin quaternary ammonium salt segment grafted on the transverse four arms is changed by adjusting the molar ratio of epichlorohydrin and the polyepichlorohydrin bridging secondary amine compound, when the molecular weight of the polyepichlorohydrin quaternary ammonium salt segment grafted on the transverse four arms is too large, it will overlap, entangle and kink in the wastewater, which is not conducive to the stretching and opening of the transverse four-arm polyepichlorohydrin quaternary ammonium salt segment, thereby affecting the demulsification effect; when the molecular weight of the polyepichlorohydrin quaternary ammonium salt segment grafted on the transverse four arms is too small, the overall quaternary ammonium salt density of the demulsifier is reduced, resulting in a poor demulsification effect.

[0090] It can be seen from Example 1 and Comparative Example 8 that, compared with conventional hyperbranched polymer quaternary ammonium salts, the present invention has better demulsification effect, especially demulsification effect at low temperature, by preparing a polymer quaternary ammonium salt with a regular structure.

[0091] It can be seen from Example 1 and Comparative Example 9 that when nano titanium dioxide modified with long fatty chains is used, its long fatty chains can be better overlapped on the network polymer quaternary ammonium salt matrix to form a stable composite structure, thereby improving the synergistic effect of the two.

[0092] It can be seen from Example 1 and Comparative Examples 10-11 that when quaternary ammonium salt-modified nano titanium dioxide or polymer quaternary ammonium salt is used alone, the demulsification effect of the reverse demulsifier deteriorates. This is because when network polymer quaternary ammonium salt and quaternary ammonium salt-modified nano titanium dioxide are used alone, a demulsifier with a regular network structure cannot be formed, resulting in a deterioration in the distribution density and uniformity of the quaternary ammonium salt group, and a demulsification effect.

Claims

1. A highly efficient composite quaternary ammonium salt reverse demulsifier, characterized in that: The invention is composed of a polymer quaternary ammonium salt and a quaternary ammonium salt-modified nano titanium dioxide, wherein the mass ratio of the polymer quaternary ammonium salt to the quaternary ammonium salt-modified nano titanium dioxide is 18-20:1; the quaternary ammonium salt-modified nano titanium dioxide is prepared by reacting nano titanium dioxide and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride; The preparation method of the polymer quaternary ammonium salt is as follows: (1) reacting 2-hydroxy-1,3-propanediamine and bromopropane in a molar ratio of 1:2 to obtain a secondary amine compound; (2) reacting the secondary amino group in the secondary amine compound with di-tert-butyl dicarbonate to obtain an amine ester compound; (3) reacting the hydroxyl group in the amine ester compound with the terminal acyl chloride polyepichlorohydrin to obtain a polyepichlorohydrin bridged amine ester compound; the molar ratio of the amine ester compound to the terminal acyl chloride polyepichlorohydrin is 2:1, and the terminal acyl chloride polyepichlorohydrin is obtained by subjecting the product obtained by the reaction of polyepichlorohydrin diol and succinic anhydride to chlorination reaction; the polyepichlorohydrin diol is obtained by subjecting ethylene glycol and epichlorohydrin in a molar ratio of 0.2 to 0.3:1 to cationic ring-opening polymerization; (4) deprotecting the tert-butyloxycarbonyl group in the polyepichlorohydrin-bridged amine ester compound to obtain a polyepichlorohydrin-bridged secondary amine compound; (5) reacting the secondary amino group in the polyepichlorohydrin-bridged secondary amine compound with epichlorohydrin to obtain a polyepichlorohydrin-bridged four-arm chlorohydrin compound; then subjecting the polyepichlorohydrin-bridged four-arm chlorohydrin compound and epichlorohydrin to a cationic ring-opening polymerization to obtain a polyepichlorohydrin-bridged four-arm polyepichlorohydrin; in the cationic ring-opening polymerization, the molar ratio of epichlorohydrin to the polyepichlorohydrin-bridged secondary amine compound used to prepare the polyepichlorohydrin-bridged four-arm chlorohydrin compound is 0.1 to 0.2:1; (6) A tertiary amino group in the polyepichlorohydrin bridged four-arm polyepichlorohydrin is subjected to a quaternization reaction with an alkyl bromide to obtain an ammonium bromide bridged product; a chlorine atom in the ammonium bromide bridged product is subjected to a quaternization reaction with triethylamine to obtain a polymer quaternary ammonium salt; the alkyl bromide is dodecane bromide, undecane bromide, n-decane bromide, n-butane bromide, n-pentane bromide, n-hexane bromide, n-heptane bromide, n-octane bromide, or n-nonane bromide.

2. The highly efficient composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: In step (1) of the method for preparing a polymer quaternary ammonium salt, sodium hydroxide is used as a catalyst when 2-hydroxy-1,3-propylenediamine and bromopropane react, and the molar ratio of 2-hydroxy-1,3-propylenediamine, bromopropane and sodium hydroxide is 1:2:2.3-2.5; the temperature of the reaction of 2-hydroxy-1,3-propylenediamine and bromopropane is 60-70°C, and the reaction time is 2-3 hours.

3. The highly efficient composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: In step (2) of the method for preparing the polymer quaternary ammonium salt, the molar ratio of di-tert-butyl dicarbonate to the secondary amine compound is 2:

1.

4. The highly efficient composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: In step (3) of the method for preparing a polymer quaternary ammonium salt, boron trifluoride etherate complex is used as a catalyst during the cationic ring-opening polymerization reaction, and the mass of the boron trifluoride etherate complex is 0.15-0.2% of the sum of the masses of ethylene glycol and epichlorohydrin; the temperature of the cationic ring-opening polymerization reaction is 0-5°C, and the time is 3-4 hours; the temperature of the reaction of polyepichlorohydrin diol and succinic anhydride is 50-60°C, and the time is 5-8 hours, and the molar ratio of polyepichlorohydrin diol to succinic anhydride is 1:2; and the acyl chloride reaction in step (3) is to mix the product obtained by the reaction of polyepichlorohydrin diol and succinic anhydride with dichlorothionyl in a mass ratio of 10:50-60, and then reflux for reaction for 24-30 hours.

5. The high-efficiency composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: The method for deprotecting the tert-butyloxycarbonyl group in the polyepichlorohydrin bridged amine ester compound in step (4) of the method for preparing the polymer quaternary ammonium salt is as follows: adding a dioxane solution of the polyepichlorohydrin bridged amine ester compound to a dioxane solution of hydrogen chloride, mixing and reacting for 4 to 5 hours, then adding sodium hydroxide, and adjusting the pH of the reaction solution to 7.5 to 8; the concentration of the dioxane solution of hydrogen chloride is 2 mol / L, and the mass ratio of the dioxane solution of the polyepichlorohydrin bridged amine ester compound to the dioxane solution of hydrogen chloride is 1:2 to 2.

5.

6. The highly efficient composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: In the step (5) of the method for preparing a polymer quaternary ammonium salt, when preparing a polyepichlorohydrin-bridged four-arm chlorohydrin compound, the molar ratio of the polyepichlorohydrin-bridged secondary amine compound to epichlorohydrin is 1:4-4.1, the reaction temperature is 58-65° C., and the reaction time is 5-7 hours. In the cationic ring-opening polymerization reaction in step (5), boron trifluoride etherate complex is used as a catalyst, and the mass of the boron trifluoride etherate complex is 0.15-0.2% of the sum of the masses of the polyepichlorohydrin-bridged secondary amine compound and epichlorohydrin.

7. The high-efficiency composite quaternary ammonium salt reverse demulsifier according to claim 1, characterized in that: In step (6) of the method for preparing a polymer quaternary ammonium salt, when the tertiary amino group in the polyepichlorohydrin-bridged four-arm polyepichlorohydrin and the alkyl bromide are subjected to a quaternization reaction, the molar ratio of the polyepichlorohydrin-bridged four-arm polyepichlorohydrin and the alkyl bromide is 1:4.5-5, the reaction temperature is 85-90°C, and the reaction time is 6-8 hours; the molar ratio of the chlorine element and triethylamine in the ammonium bromide bridging product is 1:1.1-1.3, and the temperature for the quaternization reaction of the chlorine atom in the ammonium bromide bridging product and the triethylamine is 85-90°C, and the reaction time is 6-8 hours.

8. The highly efficient composite quaternary ammonium salt reverse demulsifier according to any one of claims 1 to 7, characterized in that: The mass ratio of the nano titanium dioxide and dimethyl octadecyl [3- (trimethoxysilyl) propyl] ammonium chloride is 1:4-5, and the reaction temperature of the nano titanium dioxide and dimethyl octadecyl [3- (trimethoxysilyl) propyl] ammonium chloride is 70-80° C. and the reaction time is 28-30 hours.

9. The high-efficiency composite quaternary ammonium salt reverse demulsifier according to claim 8, characterized in that: The average particle size of the nano titanium dioxide is 25-40 nm.

10. A method for preparing a highly efficient composite quaternary ammonium salt reverse demulsifier as claimed in claim 1, characterized in that: The following steps are involved: The polymer quaternary ammonium salt and the quaternary ammonium salt modified nano titanium dioxide are mixed evenly.

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