Preparation method and application of oil-soluble reverse demulsifier

Abstract

The invention provides a preparation method and application of an oil-soluble reverse demulsifier, and the preparation method comprises the following steps: step 1, carrying out ring-opening polymerization reaction on azodinitrile and epoxypropane to obtain an azo polyether oil head; step 2, carrying out copolymerization on the azo polyether oil head, ethylene oxide and epoxypropane to obtain block azo polyether; 3, carrying out a cross-linking reaction on the block azo polyether under the action of a cross-linking agent to obtain cross-linked polyether; and step 4, carrying out a reaction on the crosslinked polyether and quaternary ammonium salt under heating to obtain the oil-soluble reverse demulsifier. The oil-soluble reverse demulsifier provided by the invention has the characteristics of good oil-water layering effect of the nonionic polyether and high oil removal rate of the polyquaternary ammonium salt, and can quickly break the balance of double electric layers of an oil-water interface, promote oil droplet coalescence, realize efficient and deep demulsification and remarkably improve the oil-water separation effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of petrochemical engineering, and particularly relates to a preparation method and application of an oil-soluble reverse demulsifier. Background Art

[0002] At present, domestic refineries all adopt the propylene ammoxidation process to produce acrylonitrile. During the production process, unreacted ammonia discharged from the reactor enters the quench tower and is neutralized by sulfuric acid, thus generating a large amount of dilute ammonium sulfate solution. Production enterprises often use the evaporation crystallization method to treat the dilute ammonium sulfate solution. During the evaporation crystallization process, crystalline solids, evaporation condensate, and evaporation concentrate are generated. The crystalline solid ammonium sulfate can be used as a fertilizer; the organic matter and ammonia nitrogen content in the evaporation condensate are relatively low, and it can be recycled or discharged after treatment; the evaporation concentrate is of the O / W type, which contains high-concentration oil substances (polymers) and an almost saturated ammonium sulfate solution, has a high viscosity, and the organic matter, ammonium sulfate, and water are mixed and adhered together, making it difficult to separate. At present, the evaporation concentrate mostly uses gravity sedimentation (vertical oil removal tank) to separate the oil and water phases. The oil phase is treated by incineration, and the water phase is recycled to the evaporator. However, due to the poor separation effect of gravity sedimentation, the water content in the oil phase is high, and the ammonium sulfate concentration is as high as about 20%, resulting in problems such as an increase in the differential pressure of the bag filter in the wastewater incineration unit, crystallization blockage, and frequent tripping of the incinerator. At the same time, it also leads to a large amount of oil in the circulating water phase and a deepening of the color of the crystalline ammonium sulfate product.

[0003] From the perspective of sewage treatment, due to the presence of various complex components such as polyacrylonitrile, aromatic compounds, and carbonyl compounds in the evaporation concentrate, it is difficult to achieve oil-water separation by conventional gravity sedimentation means. Using a reverse demulsifier can significantly improve the oil-water separation speed and effect. However, the agent will dissolve in the water phase and affect the quality of the ammonium sulfate product. Therefore, developing an oil-soluble and highly efficient reverse demulsifier is a necessary means to solve the above problems.

[0004] At present, the reverse demulsifiers developed for O / W type emulsions at home and abroad are mainly cationic and non-ionic reverse demulsifiers. The cationic type is mainly quaternary ammonium salts. This type of reverse demulsifier has a high cationicity, can quickly break the oil-water double electric layer balance, promote the aggregation of oil droplets, and then form two-phase stratification. However, it is easy to cause the flocs to be compact, wall hanging, and the emulsion layer of the concentrate gradually thickens due to the gradual accumulation of flocs in the device. The non-ionic reverse demulsifier is mainly block polyethers. This type of reverse demulsifier can reduce the interfacial film strength, realize the coalescence of oil beads, and has the characteristics of high oil removal efficiency, good oil-water interface, and non-sticking to the wall, but the oil removal speed is relatively slow. The reverse demulsifier system formed by compounding quaternary ammonium salt-based and polyether-based reverse demulsifiers can effectively improve the floc morphology and enhance the oil-water separation effect when used together. However, conventional polyethers and quaternary ammonium salts are both water-soluble and not suitable for treating ammonium sulfate wastewater. Moreover, the solvent systems of the two have poor compatibility, are easy to stratify when mixed, and it is difficult to form an effective composite system.

[0005] CN115814469A discloses a preparation method of a composite reverse demulsifier. Specifically, a straight-chain triblock amino polyether is synthesized using C12-C18 fatty amine as the initiator. The amino polyether, pH regulator, aqueous solution, and solubilizer are mixed to prepare a polyether solution. A cationic polymer is added thereto, and after mixing and stirring, it is allowed to stand and discharged to obtain a nonionic-ionic composite reverse demulsifier system. This method improves the miscibility of the polyether and the cationic polymer by adding a solubilizer (glycol ether), and enhances the oil-water separation ability of the demulsifier.

[0006] CN112300379A discloses a crosslinked polyether reverse demulsifier and its preparation method. Specifically, a poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) triblock polyether using pyridinol as the initiator is used as the raw material, and epichlorohydrin is used as the crosslinking agent. Under the action of an alkaline catalyst, a water-soluble crosslinked polyether reverse demulsifier is obtained. This reverse demulsifier is used to treat high-water-content crude oil produced liquid. Its composition is a single-component polyether, which cannot reduce the absolute value of the negative charge at the oil-water interface, and the oil removal speed is relatively slow.

[0007] CN113444237A discloses a quaternized polyether reverse demulsifier and its preparation method. Specifically, a polyether, epichlorohydrin, and trimethylamine are used as raw materials, and a reverse demulsifier containing a cationic polyether is synthesized by a one-step method.

[0008] CN112300340A discloses a nonionic-cationic copolymer containing a polyether branch chain and its preparation method. Specifically, a polyether polyol is modified with maleic anhydride, and then copolymerized with a cationic macromolecule to obtain a reverse demulsifier. This demulsifier has both demulsification and flocculation functions, and has the advantages of fast separation rate and good separated water quality for high-water-content or ultra-high-water-content crude oil emulsions.

[0009] CN106866954A discloses a cationic polyether reverse demulsifier and its preparation method. Specifically, a polyamino polyether with a certain degree of polymerization reacts with acryloyloxyethyl trimethylammonium chloride (DAC) or methacryloyloxyethyl trimethylammonium chloride (DMC) by Michael addition reaction to obtain a cationic polyether reverse demulsifier. This demulsifier contains a cationic polar group with a relatively high positive charge and has a moderate molecular weight, and has a significant effect on high-oil-content and high-suspended-solid sewage produced by chemical flooding. This reverse demulsifier is water-soluble and is mainly used to treat oily sewage with low requirements for separated water quality, and is not suitable for treating ammonium sulfate wastewater.

[0010] CN112745890A discloses an oil-soluble demulsifier for oil fields and its preparation method. Specifically, polyoxyethylene polyoxypropylene octadecanol ether and / or polyoxyethylene polyoxypropylene polyether are used as the dry agent, and polyoxymethylene dimethyl ether with a polymerization degree of 3 and / or polyoxymethylene dimethyl ether with a polymerization degree of 4 are used as the solvent. This demulsifier system can solve the problems that the existing demulsifiers have poor dispersion performance in produced fluids with complex components, high oil-water emulsification degree, and strong emulsification stability, resulting in slow oil-water separation speed and incomplete separation; and the problems of low flash point, being flammable and explosive during transportation, storage, and use in summer, and low safety; and high freezing point, unable to be used normally in severe winter. However, the structure of this demulsifier is a single-structure polyether, which cannot effectively neutralize the negative charge at the oil-water interface and break the double-layer balance, and is inferior to the compound demulsifier in terms of oil removal speed and depth.

[0011] Therefore, there is still a need in the art to further study the reverse demulsifier applicable to acrylonitrile ammonium sulfate wastewater. Summary of the Invention

[0012] The main object of the present invention is to provide a preparation method and application of an oil-soluble reverse demulsifier to overcome the defects that the reverse demulsifier for acrylonitrile ammonium sulfate wastewater in the prior art is easily soluble in water and cannot exist stably.

[0013] To achieve the above object, the present invention provides a preparation method of an oil-soluble reverse demulsifier, including the following steps:

[0014] Step 1, subject azodinitrile to ring-opening polymerization reaction with propylene oxide to obtain an azo polyether oil head;

[0015] Step 2, subject the azo polyether oil head, ethylene oxide, and propylene oxide to copolymerization to obtain a block azo polyether;

[0016] Step 3, subject the block azo polyether to cross-linking reaction under the action of a cross-linking agent to obtain a cross-linked polyether;

[0017] Step 4, react the cross-linked polyether with a quaternary ammonium salt under heating to obtain an oil-soluble reverse demulsifier.

[0018] In the preparation method of the oil-soluble reverse demulsifier of the present invention, the azodinitrile is one of azobisisobutyronitrile, azodiisovaleronitrile, and azodiisoheptonitrile; the reaction of the azodinitrile with propylene oxide is carried out in an oil-soluble solvent under the action of a ring-opening polymerization catalyst, and the ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide; the oil-soluble solvent is one of acetone, methyl ethyl ketone, methyl isobutyl ketone, and tetrahydrofuranone.

[0019] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the mass ratio of azodinitrile to propylene oxide is 2:1 - 8:1, and the dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of azodinitrile and propylene oxide; the reaction temperature of azodinitrile and propylene oxide is 100 - 120 °C, and the reaction time is 1 - 3 h.

[0020] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the reaction of the azo polyether oil head, ethylene oxide and propylene oxide is carried out under the action of a ring-opening polymerization catalyst, and the ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide. The dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of the azo polyether oil head, ethylene oxide and propylene oxide.

[0021] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the reaction temperature of the azo polyether oil head, ethylene oxide and propylene oxide is 110 - 120 °C, the mass ratio of the azo polyether oil head to ethylene oxide is 1:2 - 1:5, and the mass ratio of the azo polyether oil head to propylene oxide is 1:8 - 1:12.

[0022] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the cross-linking agent is epichlorohydrin, and the mass ratio of the block azo polyether to the cross-linking agent is 500:1 - 600:1.

[0023] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the temperature of the cross-linking reaction is 60 - 80 °C, and the time is 1 - 3 h.

[0024] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the quaternary ammonium salt is one of dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium bromide, and hexadecyl trimethyl ammonium chloride, and the dosage of the quaternary ammonium salt is 20 - 30% of the mass of the cross-linked polyether.

[0025] The preparation method of the oil-soluble reverse demulsifier of the present invention, wherein the heating temperature in step 4 is 80 - 95 °C, and the reaction time is 3 - 5 h; the reaction mixture of the cross-linked polyether and the quaternary ammonium salt is subjected to oil-water separation, and the obtained oil phase is distilled to obtain the oil-soluble reverse demulsifier.

[0026] In order to achieve the above object, the present invention also provides the application of the oil-soluble reverse demulsifier obtained by the above preparation method in the recovery of acrylonitrile ammonium sulfate wastewater.

[0027] The beneficial effects of the present invention:

[0028] The oil-soluble reverse demulsifier provided by the present invention has the characteristics of good oil-water separation effect of non-ionic polyether and fast oil removal rate of polyquaternary ammonium salt. It can quickly break the double-layer electric charge balance at the oil-water interface, promote the coalescence of oil droplets, achieve efficient and deep demulsification, and significantly improve the oil-water separation effect.

[0029] The reverse demulsifier provided by the present invention has good oil solubility and better solubility in the upper oil phase of acrylonitrile ammonium sulfate wastewater. When used to treat ammonium sulfate wastewater, it dissolves in the oil phase and enters the incinerator with the oil phase, without causing pollution to the water phase, and ensuring the quality of ammonium sulfate products on the basis of achieving efficient demulsification and oil removal.

[0030] The reverse demulsifier provided by the present invention is homogeneous and stable in the solution without stratification, and can fully exhibit the advantages of non-ionic polyether and cationic reverse demulsifier. Specific Embodiments

[0031] The technical solutions of the present invention are described in detail below. The following embodiments are implemented on the premise of the technical solutions of the present invention, and the detailed implementation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. For the structures or experimental methods without specific conditions noted in the following embodiments, they are usually in accordance with conventional conditions.

[0032] Refineries generally use the propylene ammoxidation process to produce acrylonitrile. During the production process, the unreacted ammonia discharged from the reactor enters the quench tower and is neutralized by sulfuric acid, thus generating a large amount of dilute ammonium sulfate solution. Acrylonitrile production enterprises often use the evaporation crystallization method to treat the dilute ammonium sulfate solution. During the evaporation crystallization process, an O / W type evaporation concentrate is generated, which contains high-concentration oil substances (polymers) and an almost saturated ammonium sulfate solution, with high viscosity. The organic matter, ammonium sulfate, and water are mixed and adhered together, making it difficult to separate. In addition, the high ammonium sulfate content in the separated oil phase leads to problems such as increased pressure difference of the bag filter in the wastewater incineration unit, crystallization blockage, and frequent tripping of the incinerator. At the same time, there are also problems such as high oil content in the circulating water phase and colored ammonium sulfate products obtained by evaporation crystallization.

[0033] The oil-soluble reverse demulsifier of the present invention can be used for the recovery of acrylonitrile ammonium sulfate wastewater. Specifically, it can be used for the oil-water separation of the above-mentioned evaporation concentrate. The azo-crosslinked polyether-quaternary ammonium salt demulsifier of the present invention forms a homogeneous and stable demulsification system by the electrostatic attraction of the azo group with strong power supply ability to the cationic quaternary ammonium salt, so that the non-ionic polyether and the cationic polyquaternary ammonium salt are miscible. This demulsifier system has the characteristics of good oil-water separation effect of polyether and fast oil removal rate of polyquaternary ammonium salt. It can quickly break the double-layer electric charge balance at the oil-water interface, promote the coalescence of oil droplets, achieve efficient and deep demulsification, and significantly improve the oil-water separation effect. The azo structure in the structure of the reverse demulsifier of the present invention gives it good oil solubility. After oil-water separation, it will enter the incineration unit with the oil phase, ensuring the quality of ammonium sulfate products while achieving efficient oil-water separation.

[0034] The present invention provides a preparation method of an oil-soluble reverse demulsifier. An azo-type initiator is used to initiate the copolymerization of epoxides to generate polyethers, and then a high-molecular-weight crosslinked polyether is obtained under the action of a crosslinking agent epichlorohydrin. The high-molecular-weight crosslinked polyether has good lipophilic-hydrophobic properties and has a high solubility in common organic solvents. The high-molecular-weight crosslinked polyether is dissolved in an oil-soluble solvent, and a cationic quaternary ammonium salt is added to the solution. The strong electron-donating effect of azo has an electrostatic attraction on the cationic quaternary ammonium salt, so that an azo-crosslinked polyether-quaternary ammonium salt reverse demulsifier is obtained. Moreover, the demulsifier forms a stable and uniform composite reverse demulsification system in the solvent, combining the advantages of polyether-type and cationic-type reverse demulsifiers, which can quickly sweep oil droplets, accelerate the oil-water separation speed, achieve efficient demulsification, and the reverse demulsifier has extremely low water solubility and will not return to the evaporation crystallizer with the aqueous phase, affecting the quality of ammonium sulfate products.

[0035] Specifically, the preparation method of the oil-soluble reverse demulsifier of the present invention includes the following steps:

[0036] Step 1, subject azodinitrile to ring-opening polymerization reaction with propylene oxide to obtain an azo polyether oil head;

[0037] Step 2, subject the azo polyether oil head, ethylene oxide and propylene oxide to copolymerization to obtain a block azo polyether;

[0038] Step 3, subject the block azo polyether to crosslinking reaction under the action of a crosslinking agent to obtain a crosslinked polyether;

[0039] Step 4, react the crosslinked polyether and the quaternary ammonium salt under heating to obtain an oil-soluble reverse demulsifier.

[0040] In Step 1, azodinitrile is used as the initiator and propylene oxide is used as the monomer. In one embodiment, the azodinitrile is one of azobisisobutyronitrile, azodiisovaleronitrile, azodiisoheptonitrile, and preferably azodiisoheptonitrile; the reaction of azodinitrile and propylene oxide is carried out under the action of a ring-opening polymerization catalyst and in an oil-soluble solvent. The ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, and preferably one of sodium hydroxide and potassium hydroxide; the oil-soluble solvent is, for example, an oil-soluble ketone, more specifically one of acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuranone, and preferably one of methyl ethyl ketone and methyl isobutyl ketone.

[0041] In another embodiment, the mass ratio of azodinitrile to propylene oxide is 2:1 - 8:1, preferably 3:1 - 5:1, the dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of azodinitrile and propylene oxide, preferably 0.1 - 0.2%; the reaction temperature of azodinitrile and propylene oxide is 100 - 120 °C, and the reaction time is 1 - 3 h.

[0042] In yet another embodiment, the ring-opening polymerization reaction in step 1 is carried out in a reaction kettle. An initiator azodinitrile and an oil-soluble solvent are added to the kettle, and stirred at 40 - 60 °C for 10 min to mix evenly. The dosage of the initiator is 20 - 60% of the mass of the solvent, preferably 30 - 50%. Then, a ring-opening polymerization catalyst is added, and vacuum dehydration is carried out at 90 - 100 °C. The dehydration time is, for example, 20 - 40 min. Then, propylene oxide is added, and the polymerization reaction is carried out at 100 - 120 °C, controlling the pressure at 0 - 0.4 Mpa. The reaction time is 0.5 - 3 h, preferably 1 - 3 h. After the reaction, the filter residue is filtered off to obtain an azo polyether oil head solution.

[0043] Among them, the reaction kettle is a stainless-steel reaction kettle with an operating pressure of 2 - 5 Mpa.

[0044] The azo polyether oil head obtained by the present invention has, for example, the following structure of formula 1:

[0045]

[0046] Among them, R is selected from one of methylene, ethylene, and isobutylene.

[0047] Step 2 is the preparation of block polyether. Specifically, an azo polyether oil head, ethylene oxide, and propylene oxide are used as raw materials, and the three components are copolymerized to form a block-structured polyether. The copolymerization reaction is carried out in a reaction kettle. First, the azo polyether oil head and the ring-opening polymerization catalyst are added to the kettle, and vacuum dehydration is carried out at 90 - 100 °C for 30 min. Then, the temperature is raised to 110 - 120 °C and the first copolymerization component ethylene oxide is introduced, controlling the pressure at 0 - 0.4 MPa and reacting for 0.5 - 3 h. Then, the second copolymerization component propylene oxide is introduced, controlling the pressure at 0 - 0.4 MPa and maintaining the temperature to react for 0.5 - 3 h. After filtration, block azo polyether is obtained.

[0048] In one embodiment, the ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide, preferably one of sodium hydroxide and potassium hydroxide. The dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of the azo polyether oil head, ethylene oxide, and propylene oxide, preferably 0.1 - 0.2%.

[0049] In another embodiment, the reaction temperature of the azo polyether oil head, ethylene oxide, and propylene oxide is 110 - 120 °C. The mass ratio of the azo polyether oil head to ethylene oxide is 1:2 - 1:5, preferably 1:2 - 1:3. The mass ratio of the azo polyether oil head to propylene oxide is 1:8 - 1:12.

[0050] Step 3 is the preparation of crosslinked polyether. Specifically, using block azo polyether as the monomer and epichlorohydrin as the crosslinking agent, reacting at 60 - 80 °C for 1 - 3 h, and then adding the oil-soluble solvent used in synthesizing the oil head of azo polyether for dilution to obtain a crosslinked polyether solution.

[0051] In one embodiment, first heat the block azo polyether to 60 - 80 °C, and then add the crosslinking agent for reaction.

[0052] In another embodiment, the mass ratio of block azo polyether to the crosslinking agent is 500:1 - 600:1. In the obtained crosslinked polyether solution, the mass of the solvent is 200 - 400% of the total mass of block azo polyether and epichlorohydrin.

[0053] Step 4 is the preparation of an oil-soluble reverse demulsifier. Specifically, dropwise add an aqueous solution of quaternary ammonium salt to the crosslinked polyether solution over a period of 0.5 - 3 h while keeping stirring. After the addition is completed, heat the above reaction system to 80 - 95 °C, stir and react for 3 - 5 h, then take out the mixed liquid, let it stand for 3 - 5 h, and separate the upper oil phase. Remove the solvent by vacuum distillation to obtain an azo crosslinked polyether - quaternary ammonium salt reverse demulsifier.

[0054] The quaternary ammonium salt is a long-chain quaternary ammonium salt, such as one having 10 - 20 carbons, such as dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, preferably dodecyltrimethylammonium chloride and tetradecyltrimethylammonium bromide. The dosage of the quaternary ammonium salt is 20 - 30% of the mass of the crosslinked polyether. In the aqueous solution of quaternary ammonium salt, the concentration of the quaternary ammonium salt is 20 - 40 wt%.

[0055] The reverse demulsifier of the present invention comprises azo polyether and cationic quaternary ammonium salt. The high content of nitrogen element in the azo polyether endows it with extremely strong power supply ability, forming a strong electrostatic attraction to the high-cationicity quaternary ammonium salt, enabling the non-ionic polyether and cationic polyquaternary ammonium salt to form a stable composite system in the solution, and being able to fully exhibit the advantages of non-ionic polyether and cationic reverse demulsifier.

[0056] In addition, the oil-soluble azo dinitrile structure, long-chain block polyether structure and long-chain quaternary ammonium salt structure in the reverse demulsifier provided by the present invention increase the non-polarity of the system, endowing the reverse demulsifier with good lipophilic and hydrophobic properties. Especially for acrylonitrile ammonium sulfate wastewater, the oil phase in this wastewater is mainly polyacrylonitrile. And the azo dinitrile in the structure of the reverse demulsifier of the present invention contains a certain amount of nitrile groups. According to the principle of similar solubility, the solubility of this demulsifier in the oil phase of acrylonitrile wastewater is excellent.

[0057] The technical solution of the present invention will be further described in detail through specific examples below. Unless otherwise specified, the following "%" refers to mass percentage.

[0058] Sources of raw materials or equipment: Ammonium sulfate evaporation concentrate, ammonium sulfate unit in the acrylonitrile workshop of Daqing Petrochemical; SP169 polyether demulsifier, 99%, Jiangsu Haian Petrochemical Factory; Dodecyl trimethyl ammonium chloride, 99%, Shanghai Aladdin Biochemical Technology Co., Ltd.; Cetyl trimethyl ammonium chloride, 99%, Shanghai Aladdin Biochemical Technology Co., Ltd.; Methyl isobutyl ketone, 99%, Macklin Reagent; 2,2'-Azobis(2-methylpropionitrile), 98%, Shanghai Aladdin Biochemical Technology Co., Ltd.; 2,2'-Azobis(2,4-dimethylpentanenitrile), 98%, Shanghai Aladdin Biochemical Technology Co., Ltd.; 2,2'-Azobis(2,4-dimethylheptanenitrile), 98%, Shanghai Aladdin Biochemical Technology Co., Ltd.; KOH, 99%, Liaoning Quanrui; Propylene oxide, 99%, Hunan Qilu New Materials Technology Co., Ltd.; Ethylene oxide, 99%, Hunan Qilu New Materials Technology Co., Ltd.; Reactor, 500 ml, Beijing Century Senlang.

[0059] Comparative Example 1

[0060] (1) Add 50 ml of methyl isobutyl ketone and 20 g of 2,2'-azobis(2-methylpropionitrile) to the reactor, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 1 h, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0061] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH to the reactor, conduct vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 propylene oxide and control the pressure at 0.2 Mpa, maintain the temperature for reaction for 12 h, and then filter to obtain a block azo polyether solution.

[0062] (3) Add the block azo polyether solution prepared in the above step to the kettle reactor, heat up to 80 °C, then add 0.68 g of crosslinking agent epichlorohydrin, maintain the temperature for reaction for 1 h. After the reaction, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution, numbered Demulsifier 1.

[0063] Example 1

[0064] (1) Add 50 ml of methyl isobutyl ketone and 20 g of 2,2'-azobis(2-methylpropionitrile) to the reactor, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 1 h, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0065] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, raise the temperature to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to be 0.2 Mpa, keep the temperature for reaction for 12 h, and then obtain the block azo polyether solution after filtration.

[0066] (3) Add the block azo polyether solution prepared in the above step into the kettle reactor, heat to 80 °C, then add 0.68 g of epichlorohydrin as the cross-linking agent, keep the temperature for reaction for 1 h, after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain the cross-linked polyether solution.

[0067] (4) Dropwise add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) into the cross-linked polyether solution obtained in the above step, the dropping time is 2 h, keep stirring during the dropping process, after the dropping is completed, raise the temperature of the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain the nonionic-cationic composite reverse demulsifier, numbered demulsifier 2.

[0068] Example 2

[0069] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into the reaction kettle, raise the temperature to 50 °C and stir for 10 min to completely dissolve the initiator, then add 25 mg of NaOH, raise the temperature to 90 °C for vacuum dehydration for 30 min, then add 5 g of propylene oxide, raise the temperature to 100 - 120 °C for reaction and control the pressure to be 0.2 Mpa, after the reaction for 1 h is completed, filter to remove the filter residue to obtain the azo polyether oil head solution.

[0070] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of NaOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, raise the temperature to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to be 0.2 Mpa, keep the temperature for reaction for 12 h, and then obtain the block azo polyether solution after filtration.

[0071] (3) Add the block azo polyether solution prepared in the above step into the kettle reactor, heat to 80 °C, then add 0.68 g of epichlorohydrin as the cross-linking agent, keep the temperature for reaction for 1 h, after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain the cross-linked polyether solution.

[0072] (4) 30 mL of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) was added dropwise to the crosslinked polyether solution obtained in the above step over a period of 2 h while stirring. After the addition was complete, the reaction system was heated to 95 °C and stirred for 3 h. The mixture was then taken out, allowed to stand for 5 h, and the upper oil phase was separated. The solvent was removed by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, designated as Demulsifier 3.

[0073] Example 3

[0074] (1) 50 mL of methyl isobutyl ketone and 20 g of azobisisobutyronitrile were added to a reaction kettle. The temperature was raised to 50 °C and stirred for 10 min to completely dissolve the initiator. Then, 25 mg of MgOH was added, and the temperature was raised to 90 °C for vacuum dehydration for 30 min. Next, 5 g of propylene oxide was added, and the temperature was raised to 100 - 120 °C for reaction while controlling the pressure at 0.2 Mpa. After the reaction ended after 1 h, the filter residue was removed by filtration to obtain an azo polyether oil head solution.

[0075] (2) The azo polyether oil head solution prepared in the above step and 0.3 g of MgOH were added to the reaction kettle. Vacuum dehydration was carried out at 90 °C for 30 min, the temperature was raised to 110 °C, and 75 g of ethylene oxide was introduced while controlling the pressure to be less than 0.4 Mpa. The temperature was maintained for reaction for 0.5 - 3 h. Then, 270 g of propylene oxide was added and the pressure was controlled at 0.2 Mpa. After reacting for 12 h while maintaining the temperature, the solution was filtered to obtain a block azo polyether solution.

[0076] (3) The block azo polyether solution prepared in the above step was added to a kettle reactor, heated to 80 °C, and then 0.68 g of epichlorohydrin as a crosslinking agent was added. The reaction was carried out while maintaining the temperature for 1 h. After the reaction ended, 30 mL of methyl isobutyl ketone was added for dilution to obtain a crosslinked polyether solution.

[0077] (4) 30 mL of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) was added dropwise to the crosslinked polyether solution obtained in the above step over a period of 2 h while stirring. After the addition was complete, the reaction system was heated to 95 °C and stirred for 3 h. The mixture was then taken out, allowed to stand for 5 h, and the upper oil phase was separated. The solvent was removed by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, designated as Demulsifier.

[0078] Example 4

[0079] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into the reaction kettle, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of CaOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 1 h, filter to remove the filter residue to obtain the azo polyether oil head solution.

[0080] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of CaOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure at 0.2 Mpa. After keeping the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0081] (3) Add the block azo polyether solution prepared in the above step into the autoclave reactor, heat up to 80 °C and then add 0.68 g of epichlorohydrin as the crosslinking agent, keep the temperature for reaction for 1 h. After the reaction, add 30 ml of methyl isobutyl ketone for dilution to obtain the crosslinked polyether solution.

[0082] (4) Dropwise add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) into the crosslinked polyether solution obtained in the above step, and the dropping time is 2 h. Keep stirring during the dropping process. After the dropping is completed, heat up the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain the non-ionic - cationic composite reverse demulsifier, numbered demulsifier 5.

[0083] Example 5

[0084] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into the reaction kettle, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 3 h, filter to remove the filter residue to obtain the azo polyether oil head solution.

[0085] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure at 0.2 Mpa. After keeping the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0086] (3) Add the block azo polyether solution prepared in the above steps into a kettle reactor, heat it to 80 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h, and after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0087] (4) Add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) dropwise to the crosslinked polyether solution obtained in the above steps. The dropping time is 2 h, and stirring is maintained during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 6.

[0088] Example 6

[0089] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into a reaction kettle, heat it to 50 °C and stir for 10 min to completely dissolve the initiator, then add 25 mg of KOH, heat it to 90 °C for vacuum dehydration for 30 min, then add 5 g of propylene oxide, heat it to 100 - 120 °C for reaction and control the pressure to 0.2 Mpa. After the reaction is completed in 3 h, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0090] (2) Add the azo polyether oil head solution prepared in the above steps and 0.3 g of KOH into the reaction kettle, conduct vacuum dehydration at 90 °C for 30 min, heat it to 120 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to 0.2 Mpa, maintain the temperature for reaction for 12 h, and then obtain a block azo polyether solution after filtration.

[0091] (3) Add the block azo polyether solution prepared in the above steps into a kettle reactor, heat it to 80 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h, and after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0092] (4) Add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) dropwise to the crosslinked polyether solution obtained in the above steps. The dropping time is 2 h, and stirring is maintained during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 7.

[0093] Example 7

[0094] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into the reaction kettle, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure to 0.2 Mpa. After the reaction for 3 h, filter to remove the residue to obtain the azo polyether oil head solution.

[0095] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to 0.2 Mpa. After keeping the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0096] (3) Add the block azo polyether solution prepared in the above step into the autoclave reactor, heat up to 60 °C and then add 0.68 g of epichlorohydrin as the crosslinking agent, keep the temperature for reaction for 1 h. After the reaction, add 30 ml of methyl isobutyl ketone for dilution to obtain the crosslinked polyether solution.

[0097] (4) Dropwise add 30 ml of aqueous solution of dodecyltrimethylammonium chloride (40 wt%) into the crosslinked polyether solution obtained in the above step, and the dropping time is 2 h. Keep stirring during the dropping process. After the dropping is completed, heat up the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain the non-ionic - cationic composite reverse demulsifier, numbered demulsifier 8.

[0098] Example 8

[0099] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azobisisobutyronitrile into the reaction kettle, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure to 0.2 Mpa. After the reaction for 3 h, filter to remove the residue to obtain the azo polyether oil head solution.

[0100] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, keep the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to 0.2 Mpa. After keeping the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0101] (3) Add the block azo polyether solution prepared in the above step into a kettle reactor, heat it to 60 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 3 h, and after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0102] (4) Dropwise add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step. The dropping time is 2 h, and stirring is maintained during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 9.

[0103] Example 9

[0104] (1) Add 50 ml of methyl isobutyl ketone and 24 g of azodiisovaleronitrile into a reaction kettle, heat it to 50 °C and stir for 10 min to completely dissolve the initiator, then add 25 mg of KOH, heat it to 90 °C for vacuum dehydration for 30 min, then add 5 g of propylene oxide, heat it to 100 - 120 °C for reaction and control the pressure to 0.2 Mpa. After the reaction is completed in 1 h, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0105] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, perform vacuum dehydration at 90 °C for 30 min, heat it to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure to 0.2 Mpa, maintain the temperature for reaction for 12 h, and then filter to obtain a block azo polyether solution.

[0106] (3) Add the block azo polyether solution prepared in the above step into a kettle reactor, heat it to 80 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h, and after the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0107] (4) Dropwise add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step. The dropping time is 2 h, and stirring is maintained during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 10.

[0108] Example 10

[0109] (1) Add 50 ml of methyl isobutyl ketone and 30 g of azodiisooctanenitrile to the reactor, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 1 h, filter to remove the residue to obtain the azo polyether oil head solution.

[0110] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH to the reactor, conduct vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure at 0.2 Mpa. After maintaining the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0111] (3) Add the block azo polyether solution prepared in the above step to the autoclave reactor, heat up to 80 °C and then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h. After the reaction, add 30 ml of methyl isobutyl ketone for dilution to obtain the crosslinked polyether solution.

[0112] (4) Dropwise add 30 ml of an aqueous solution of dodecyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step over 2 h, keep stirring during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, and separate the upper oil phase. Remove the solvent by vacuum distillation to obtain the nonionic-cationic composite reverse demulsifier, numbered demulsifier 11.

[0113] Example 11

[0114] (1) Add 50 ml of methyl isobutyl ketone and 20 g of azodiisobutyronitrile to the reactor, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C for vacuum dehydration for 30 min, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction for 1 h, filter to remove the residue to obtain the azo polyether oil head solution.

[0115] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH to the reactor, conduct vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure at 0.2 Mpa. After maintaining the temperature for reaction for 12 h, filter to obtain the block azo polyether solution.

[0116] (3) Add the block azo polyether solution prepared in the above steps and 10 mg of KOH into a kettle reactor, heat it to 80 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h. After the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0117] (4) Dropwise add 30 ml of an aqueous solution of cetyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step over 2 h, keep stirring during the dropping process. After the dropping is completed, raise the temperature of the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 12.

[0118] Example 12

[0119] (1) Add 50 ml of methyl isobutyl ketone and 24 g of azodiisovaleronitrile into a reaction kettle, raise the temperature to 50 °C and stir for 10 min to completely dissolve the initiator, then add 25 mg of KOH, raise the temperature to 90 °C for vacuum dehydration for 30 min, then add 5 g of propylene oxide, raise the temperature to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After the reaction is completed in 1 h, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0120] (2) Add the azo polyether oil head solution prepared in the above steps and 0.3 g of KOH into the reaction kettle, conduct vacuum dehydration at 90 °C for 30 min, raise the temperature to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h, then add 270 g of propylene oxide and control the pressure at 0.2 Mpa, maintain the temperature for reaction for 12 h, and then obtain a block azo polyether solution through filtration.

[0121] (3) Add the block azo polyether solution prepared in the above steps into a kettle reactor, heat it to 80 °C, then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h. After the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0122] (4) Dropwise add 30 ml of an aqueous solution of cetyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step over 2 h, keep stirring during the dropping process. After the dropping is completed, raise the temperature of the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, separate the upper oil phase, and remove the solvent by vacuum distillation to obtain a nonionic-cationic composite reverse demulsifier, numbered demulsifier 13.

[0123] Example 13

[0124] (1) Add 50 ml of methyl isobutyl ketone and 24 g of azodiisooctanenitrile into a reaction kettle, heat up to 50 °C and stir for 10 min to completely dissolve the initiator. Then add 25 mg of KOH, heat up to 90 °C and carry out vacuum dehydration for 30 min. Next, add 5 g of propylene oxide, heat up to 100 - 120 °C for reaction and control the pressure at 0.2 Mpa. After 1 h of reaction, filter to remove the filter residue to obtain an azo polyether oil head solution.

[0125] (2) Add the azo polyether oil head solution prepared in the above step and 0.3 g of KOH into the reaction kettle, carry out vacuum dehydration at 90 °C for 30 min, heat up to 110 °C and introduce 75 g of ethylene oxide, control the pressure to be less than 0.4 Mpa, maintain the temperature for reaction for 0.5 - 3 h. Then add 270 g of propylene oxide and control the pressure at 0.2 Mpa, maintain the temperature for reaction for 12 h, and then obtain a block azo polyether solution after filtration.

[0126] (3) Add the block azo polyether solution prepared in the above step into a kettle reactor, heat up to 80 °C and then add 0.68 g of epichlorohydrin as the crosslinking agent, maintain the temperature for reaction for 1 h. After the reaction is completed, add 30 ml of methyl isobutyl ketone for dilution to obtain a crosslinked polyether solution.

[0127] (4) Dropwise add 30 ml of an aqueous solution of cetyltrimethylammonium chloride (40 wt%) to the crosslinked polyether solution obtained in the above step, and the dropping time is 2 h. Keep stirring during the dropping process. After the dropping is completed, heat the above reaction system to 95 °C, stir and react for 3 h, then take out the mixed solution, let it stand for 5 h, and separate the upper oil phase. Remove the solvent by vacuum distillation to obtain a nonionic - cationic composite reverse demulsifier, numbered demulsifier 14.

[0128] Example 14

[0129] The difference between this example and Example 13 is that the solvents in steps (1) and (3) are replaced with methyl ethyl ketone, and finally demulsifier 15 is obtained.

[0130] Example 15

[0131] The difference between this example and Example 13 is that the solvents in steps (1) and (3) are replaced with acetone, and finally demulsifier 16 is obtained.

[0132] Example 16

[0133] The difference between this example and Example 13 is that the amount of ethylene oxide in step 2 is adjusted to 54 g, and finally demulsifier 17 is obtained.

[0134] Example 17

[0135] The difference between this example and Example 6 is that the dosage of ethylene oxide in Step 2 is adjusted to 135 g, and finally demulsifier 18 is obtained.

[0136] Example 18

[0137] The difference between this example and Example 13 is that the dosage of propylene oxide in Step 2 is adjusted to 216 g, and finally demulsifier 19 is obtained.

[0138] Example 19

[0139] The difference between this example and Example 13 is that the dosage of propylene oxide in Step 2 is adjusted to 324 g, and finally demulsifier 20 is obtained.

[0140] Example 20

[0141] The difference between this example and Example 13 is that the dosage of epichlorohydrin in Step 3 is adjusted to 0.62 g, and finally demulsifier 21 is obtained.

[0142] Example 21

[0143] The difference between this example and Example 13 is that the dosage of epichlorohydrin in Step 3 is adjusted to 0.75 g, and finally demulsifier 22 is obtained.

[0144] Different types of demulsifiers including the present invention are used to demulsify ammonium sulfate wastewater samples. The specific operation is to add a certain amount of demulsifier into the water sample, then manually shake the water sample 20 times to mix evenly, and then heat the wastewater bottle to 80 °C for demulsification. The dosage of the demulsifier and the demulsification time are adjusted according to the situation. No reverse demulsifier is added in No. 1, commercial demulsifier SP169 is used in No. 2a and 2b, crosslinked polyether without quaternary ammonium salt is used as the demulsifier in No. 3a and 3b, and the composite reverse demulsifier provided by the present invention is used in No. 4 - 26. Among them, the dosage of the demulsifier is adjusted in No. 25 - 26. The oil content in the aqueous phase and the interface situation after demulsification are shown in Table 1.

[0145] Analysis method:

[0146] (1) The oil content in the aqueous phase obtained after demulsifying ammonium sulfate evaporation concentrate with demulsifiers 1 - 7 prepared in the examples and demulsifier SP169 is determined according to "HJ637 - 2018 Water Quality - Determination of Petroleum and Animal Oils by Infrared Spectrophotometry".

[0147] (2) The oil - water interface situation when demulsifying ammonium sulfate evaporation concentrate with demulsifiers 1 - 7 prepared in the examples and demulsifier SP169 is determined according to "SY / T5797 - 93 Evaluation Method for the Performance of Demulsifiers for Oil - in - Water Emulsions". The oil - water interface condition is recorded with the following words:

[0148] A: Clear; B: Blurry (with bubbles or lace); C: With an emulsion layer

[0149] Table 1 Demulsification of ammonium sulfate wastewater

[0150]

[0151]

[0152] As can be seen from the data in Table 1, when no demulsifier is added, the wastewater is severely emulsified, there is no obvious stratification, and the oil content is as high as 235 mg / L; when using the SP169 demulsifier, the oil content in the water is 145 - 150 mg / L, and the oil-water interface is blurry; when using Demulsifier 1, the oil content in the water is 75 - 102 mg / L, and the oil-water interface is blurry; when using the demulsifier of the present invention, the oil content in the water is significantly reduced, the water phase is clear, and the oil-water interface is clear. This shows that the oil-soluble reverse demulsifier prepared by the present invention has high oil removal efficiency, good oil-water stratification effect, and good oil solubility, and does not pollute the water phase.

[0153] Of course, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of an oil-soluble reverse demulsifier, characterized in that, it comprises the following steps: Step 1, subject azodinitrile to ring-opening polymerization reaction with propylene oxide to obtain an azo polyether oil head; Step 2, subject the azo polyether oil head, ethylene oxide and propylene oxide to copolymerization to obtain a block azo polyether; Step 3, subject the block azo polyether to cross-linking reaction under the action of a cross-linking agent to obtain a cross-linked polyether; Step 4, react the cross-linked polyether with a quaternary ammonium salt under heating to obtain an oil-soluble reverse demulsifier.

2. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, the azodinitrile is one of azobisisobutyronitrile, azodiisovaleronitrile, azodiisoheptonitrile; the reaction of the azodinitrile with propylene oxide is carried out under the action of a ring-opening polymerization catalyst and in an oil-soluble solvent, and the ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide; the oil-soluble solvent is one of acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuranone.

3. The preparation method of the oil-soluble reverse demulsifier according to claim 2, characterized in that, in Step 1, the mass ratio of the azodinitrile to propylene oxide is 2:1 - 8:1, and the dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of the azodinitrile and propylene oxide; the reaction temperature of the azodinitrile and propylene oxide is 100 - 120°C, and the reaction time is 1 - 3 h.

4. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, the reaction of the azo polyether oil head, ethylene oxide and propylene oxide is carried out under the action of a ring-opening polymerization catalyst, the ring-opening polymerization catalyst is one of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, and the dosage of the ring-opening polymerization catalyst is 0.05 - 0.3% of the total mass of the azo polyether oil head, ethylene oxide and propylene oxide.

5. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, in Step 2, the reaction temperature of the azo polyether oil head, ethylene oxide and propylene oxide is 110 - 120°C, the mass ratio of the azo polyether oil head to ethylene oxide is 1:2 - 1:5, and the mass ratio of the azo polyether oil head to propylene oxide is 1:8 - 1:

12.

6. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, the cross-linking agent is epichlorohydrin, and the mass ratio of the block azo polyether to the cross-linking agent is 500:1 - 600:

1.

7. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, the temperature of the cross-linking reaction is 60 - 80°C, and the time is 1 - 3 h.

8. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, the quaternary ammonium salt is one of dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and the dosage of the quaternary ammonium salt is 20 - 30% of the mass of the cross-linked polyether.

9. The preparation method of the oil-soluble reverse demulsifier according to claim 1, characterized in that, The temperature for heating in Step 4 is 80 - 95 °C, and the reaction time is 3 - 5 h; the reaction mixture of the crosslinked polyether and the quaternary ammonium salt is subjected to oil-water separation, and the obtained oil phase is distilled to obtain an oil-soluble reverse demulsifier.

10. Application of the oil-soluble reverse demulsifier obtained by the preparation method according to any one of claims 1 - 9 in the recovery of acrylonitrile ammonium sulfate wastewater.

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