Hyperbranched chain polyether demulsifier and preparation method thereof

Abstract

The invention relates to a hyperbranched multi-branched chain polyether demulsifier and a preparation method thereof.The preparation method comprises the steps that firstly, vinyl trithiocarbonate, AIBN, p-chloromethyl styrene and MDO are added into a reaction flask, then an organic solvent is added, the materials are stirred and mixed to be uniform, inert gas is introduced for bubbling for 30 min, and then the temperature is increased for reaction under protection of the inert gas; and after the reaction is completed, removing inert gas, cooling to room temperature, supplementing the organic solvent for dilution, adding CTAB and mPEG, adding a certain amount of sodium hydroxide solution, heating for reacting overnight, cooling to room temperature, adding into absolute ether solution, filtering, and drying in vacuum to obtain the product. The hyperbranched multi-branched chain polydemulsifier with main chain polyester and branched chain polyether has the characteristics of large molecular weight, high branching degree, long molecular chain, multiple aromatic rings and the like, is high in universality, can be used for quickly demulsifying different types of crude oil, is small in dosage and easy to degrade, and can also reduce pollution to the environment.

Description

Technical Field

[0001] The invention relates to the technical field of demulsifiers, and in particular to a hyperbranched multi-chain polyether demulsifier and a preparation method thereof. Background Art

[0002] Petroleum is called "the blood of industry" and has extremely high application value in industrial development. With the continuous exploitation of crude oil in various countries, its storage volume is decreasing. At the same time, in the process of exploitation, with the promotion and application of alkali flooding, surfactant flooding, polymer flooding and other technologies, the water content of crude oil emulsion increases, the oilfield sewage is seriously emulsified, and the difficulty of demulsification increases. Chemical demulsifier is a commonly used demulsifier, including SP series, AP series, AE series and OP series. Chemical demulsifier can be molecularly designed according to the components of crude oil produced fluid from different oil fields, and a variety of special demulsifiers have been developed, but it also causes problems such as poor universality and harsh application conditions of traditional chemical demulsifiers. Among the many series of demulsifiers, polyether demulsifiers (OP series) are more widely used. They are mostly block-polymerized with ethylene oxide, propylene oxide and other components. They have the advantages of acid and alkali resistance and obvious crude oil dehydration effect, but the demulsification effect is significantly worse at high temperature, and it is difficult to degrade and easily causes secondary pollution to the environment. With the continuous development of crude oil, the performance requirements for demulsifiers are becoming higher and higher. Therefore, it is necessary to strengthen the research and development and innovation of new demulsifiers. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention aims to provide a hyperbranched demulsifier containing polyether and polyester structures, which has a special structure, rich functional groups, good demulsification properties and high universality.

[0004] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a hyperbranched multi-branched polyether demulsifier comprises the following steps: S1. Add vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane (MDO) into a reaction bottle, then add an organic solvent and stir to mix evenly, introduce inert gas bubbling for 30 minutes, then heat to 70-80°C under the protection of inert gas and react for 6-8 hours; S2. After the reaction is completed, remove the inert gas, cool to room temperature, add organic solvent for dilution, add CTAB and methoxy polyethylene glycol, add a certain amount of sodium hydroxide solution, heat to 70-80 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0005] Further, the structural formula of the vinyl trithiocarbonate is .

[0006] Furthermore, the molar ratio of the vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane is 1:0.2:30-60:40-70.

[0007] Furthermore, the organic solvent is a mixed solution of equal volumes of toluene and N,N-dimethylformamide.

[0008] Furthermore, the molecular weight of the methoxy polyethylene glycol is 400-1000, and the molar ratio of the methoxy polyethylene glycol to p-chloromethylstyrene is 1-1.5:1.

[0009] Furthermore, the mass fraction of the sodium hydroxide solution is 30%.

[0010] The present invention further provides a hyperbranched multi-branched polyether demulsifier prepared by the preparation method as described above.

[0011] Among the topological structures of many polymer chemical demulsifiers, the order of demulsification ability should be star-shaped > branch-shaped > comb-shaped > linear. Therefore, in this case, a hyperbranched polymer was prepared by SCVP-RAFT polymerization, and MDO was used as a comonomer to polymerize with p-chloromethylstyrene free radicals. p-chloromethylstyrene has a similar conjugated aromatic ring chemical structure with asphaltene, and forms a strong π-π interaction with asphaltene. It is a functional structure often introduced in the preparation of demulsifiers. In this case, p-chloromethylstyrene was selected. In addition to introducing a benzene ring structure to improve the adsorption of asphaltene, the chloromethyl group at the para position of the benzene ring can also be used as an active site to react with methoxy polyethylene glycol to form a long polyether chain on its side chain. The monomer MDO opens the ring to form a main chain polyester structure during the polymerization process, making the hyperbranched macromolecular polymer degradable and reducing the harm to the environment. The rich ester groups and polyethers have good lipophilic and hydrophilic properties, which can reduce the strength of the interfacial film, and the hyperbranched polymer chains and long side chains can be quickly adsorbed on the surface of oil droplets to achieve the purpose of rapid demulsification and oil removal.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention prepares a hyperbranched multi-branched polyether demulsifier based on the SCVP-RAFT method and combined with the chlorine substitution method, which has the characteristics of large molecular weight, high degree of branching, long molecular chain, multiple aromatic rings, etc., has high universality, can quickly demulsify different types of crude oil, uses a small amount of demulsifier and is easy to degrade, and can also reduce pollution to the environment. DETAILED DESCRIPTION

[0013] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0015] Embodiment: A hyperbranched multi-branched polyether demulsifier is prepared by the following preparation method: S1. Add vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane (MDO) into a reaction bottle, then add an organic solvent and stir to mix evenly, introduce inert gas bubbling for 30 minutes, then heat to 70-80°C under the protection of inert gas and react for 6-8 hours; S2. After the reaction is completed, remove the inert gas, cool to room temperature, add organic solvent for dilution, add CTAB and methoxy polyethylene glycol (mPEG400-1000), add a certain amount of sodium hydroxide solution, heat to 70-80 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0016] Unless otherwise specified, the raw materials used in the above reaction process can be purchased from the market, wherein the organic solvent is a mixed solution of equal volumes of toluene and N,N-dimethylformamide (DMF); the vinyl trithiocarbonate is prepared by referring to paragraph [0026-0029] of the applicant's patent 2020110194314.

[0017] Embodiment 1: S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 30 mmol of p-chloromethylstyrene and 70 mmol of MDO into a reaction flask, then add 10 ml of an organic solvent and stir to mix evenly, introduce argon gas for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 30 mmol mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0018] Embodiment 2: S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO into a reaction flask, then add 10 ml of an organic solvent and stir to mix evenly, introduce argon gas for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 50 mmol mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0019] Embodiment 3: S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 60 mmol of p-chloromethylstyrene and 40 mmol of MDO into a reaction flask, then add 10 ml of an organic solvent and stir to mix evenly, introduce argon gas for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 60 mmol mPEG400, add 40 g of 30 wt% sodium hydroxide solution, raise the temperature to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0020] Embodiment 4: S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO into a reaction flask, then add 10 ml of an organic solvent and stir to mix evenly, introduce argon gas for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 50 mmol mPEG600, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0021] Embodiment 5: S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO into a reaction flask, then add 10 ml of an organic solvent and stir to mix evenly, introduce argon gas for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 50 mmol mPEG1000, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0022] Comparative Example: S1. Add 0.2 mmol AIBN, 60 mmol p-chloromethylstyrene and 40 mmol MDO into the reaction bottle, then add the organic solvent and stir to mix evenly, introduce argon gas to bubble for 30 min, then heat to 80 °C under argon protection and react for 8 h; S2. After the reaction is completed, remove the argon gas, cool to room temperature, add 40 ml of organic solvent for dilution, add catalytic amount of CTAB and 30 mmol mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

[0023] Demulsifier performance test: The demulsifier prepared as above was used to evaluate the demulsification performance of Jiangsu Oilfield Wei 5 crude oil. According to the industry standard SY-T5281-2000 crude oil demulsifier performance test method, the water content of the oil sample was 46%, the test temperature was 50°C, and the test results were recorded in Table 1.

[0024] Table 1 As can be seen from the above table, in the present invention, a hyperbranched multi-branched polymer material of a main chain polyester and a branched polyether prepared by the SCVP-RAFT method in combination with the chlorine substitution method can quickly demulsify crude oil. Comparing Examples 1-3, it can be found that the effect is better when the molar ratio of 4-chloromethylstyrene to MDO is 1:1 during the polymerization process. The main chain ester group formed by the ring opening of MDO can increase the molecular spatial structure of the demulsifier, so that the molecular chain grows, and the random copolymer formed with 4-chloromethylstyrene can also graft more polyether chains, thereby reducing the surface tension of the crude oil emulsion, thereby achieving a good demulsification effect; comparing Examples 3 and 4-5, it can be found that the larger the molecular weight of methoxypolyethylene glycol, the stronger the surface activity of the demulsifier, and the demulsification performance of Examples 1-4 increases with the increase of the demulsifier concentration and the extension of the demulsification time, and the dehydration rate gradually increases, but the concentration of Example 5 does not change much, because the molecular chain of mPEG is longer and the hydrophilicity is higher. It is adsorbed on the oil-water interface after supersaturation to form micelles, and the dehydration rate is no longer increased. In contrast, the comparative example prepared a linear multi-branched polymer, which has no obvious effect when used as a demulsifier, and a better demulsification effect can only be obtained when the dosage is higher.

[0025] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a hyperbranched multi-branched polyether demulsifier, characterized in that: The steps include: S1. Add vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane into a reaction flask, then add an organic solvent and stir to mix evenly, introduce an inert gas to bubble for 30 minutes, then heat to 70-80°C under the protection of inert gas and react for 6-8 hours; S2. After the reaction is completed, remove the inert gas, cool to room temperature, add organic solvent for dilution, add CTAB and methoxy polyethylene glycol, add a certain amount of sodium hydroxide solution, heat to 70-80 °C and react overnight, cool to room temperature, add to anhydrous ether solution, filter and vacuum dry.

2. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, wherein The structural formula of the vinyl trithiocarbonate is .

3. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, wherein The molar ratio of the vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane is 1:0.2:30-60:40-70.

4. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, wherein The organic solvent is a mixed solution of equal volumes of toluene and N,N-dimethylformamide.

5. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, characterized in that: The molecular weight of the methoxy polyethylene glycol is 400-1000, and the molar ratio of the methoxy polyethylene glycol to p-chloromethylstyrene is 1-1.5:

1.

6. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, characterized in that: The mass fraction of the sodium hydroxide solution is 30%.

7. A hyperbranched multi-branched polyether demulsifier prepared by the preparation method according to any one of claims 1 to 6.

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