A hyperbranched multi-branched polyether demulsifier and its preparation method

Abstract

The present invention relates to a hyperbranched multi-branched polyether demulsifier and a preparation method thereof. First, vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and MDO are added into a reaction flask, and then an organic solvent is added and stirred to mix evenly. An inert gas is introduced for bubbling for 30 minutes, and then the reaction is carried out under the protection of the inert gas by heating. After the reaction is completed, the inert gas is removed, and the temperature is lowered to room temperature. The organic solvent is added for dilution, CTAB and mPEG are added, a certain amount of sodium hydroxide solution is added, and the reaction is carried out overnight by heating. After the temperature is lowered to room temperature, it is added into an anhydrous ether solution, filtered and dried under vacuum to obtain the product. The present invention prepares a hyperbranched multi-branched polyether demulsifier with a main chain polyester and branched polyethers, which has the characteristics of large molecular weight, high degree of branching, long molecular chain, multiple aromatic rings, etc. It has high universality, can quickly demulsify different types of crude oil, has a small dosage of the demulsifier and is easy to degrade, and can also reduce environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of demulsifiers, and more particularly to a hyperbranched multi-branched polyether demulsifier and a preparation method thereof. Background Art

[0002] Petroleum is known as 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 is decreasing day by day. At the same time, in the exploitation process, with the popularization and application of technologies such as alkali flooding, surfactant flooding, and polymer flooding, the water content of crude oil emulsions increases, and the emulsification of oilfield sewage is serious, resulting in increased demulsification difficulty. Chemical demulsifiers are a commonly used type of demulsifying agent, including SP series, AP series, AE series, and OP series, etc. Chemical demulsifiers can be molecularly designed according to the components of crude oil produced fluids in different oilfields to develop a variety of special demulsifiers, but this also causes problems such as poor universality and harsh application conditions of traditional chemical demulsifiers. Among many series of demulsifiers, polyether demulsifiers (OP series) are more widely used. They are mostly formed by block polymerization of ethylene oxide, propylene oxide, and other components, and have advantages such as acid and alkali resistance and obvious crude oil dehydration effect. However, the demulsification effect deteriorates significantly at high temperatures, and they are difficult to degrade and easily cause secondary pollution to the environment. With the continuous development of crude oil, the performance requirements for demulsifiers are getting higher and higher. Therefore, it is necessary to strengthen the research and innovation of new demulsifiers. Summary of the Invention

[0003] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a hyperbranched demulsifier containing polyether and polyester structures, which has a special structure, rich functional groups, good demulsification performance and high universality.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A preparation method of a hyperbranched multi-branched polyether demulsifier, comprising the following steps:

[0006] S1. Add vinyl trithiocarbonate, AIBN, p-chloromethylstyrene, and 2-methylene-1,3-dioxepane (MDO) into a reaction flask, then add an organic solvent and stir to mix evenly. Bubble an inert gas for 30 min, and then heat to 70 - 80 °C under the protection of the inert gas and react for 6 - 8 h;

[0007] S2. After the reaction is completed, remove the inert gas, cool to room temperature, add an organic solvent for dilution, add CTAB and methoxypolyethylene glycol, add a certain amount of sodium hydroxide solution, heat to 70 - 80 °C and react overnight. After cooling to room temperature, add it to an anhydrous ether solution, filter and dry under vacuum.

[0008] Further, the structural formula of the vinyl trithiocarbonate is 。

[0009] Further, the molar ratio of the vinyl trithiocarbonate, AIBN, p-chloromethylstyrene, and 2-methylene-1,3-dioxepane is 1:0.2:30-60:40-70.

[0010] Further, the organic solvent is a mixed solution of toluene and N,N-dimethylformamide in equal volumes.

[0011] Further, the molecular weight of the methoxypolyethylene glycol is 400-1000, and the molar ratio thereof to p-chloromethylstyrene is 1-1.5:1.

[0012] Further, the mass fraction of the sodium hydroxide solution is 30%.

[0013] The present invention further provides a hyperbranched multi-branched polyether demulsifier prepared by the preparation method as described above.

[0014] Among the topological structures of numerous polymer chemical demulsifiers, the order of demulsification ability should be star-shaped > dendritic > comb-shaped > linear. Therefore, in this case, a hyperbranched polymer was prepared by the SCVP-RAFT polymerization method. Using MDO as a comonomer to carry out free radical polymerization with p-chloromethylstyrene, p-chloromethylstyrene has a similar conjugated aromatic ring chemical structure to asphaltene and forms a strong π-π interaction with asphaltene, which is a functional structure often introduced in the preparation of demulsifiers. In this case, the selection of p-chloromethylstyrene not only introduces a benzene ring structure to improve the adsorption effect on asphaltene, but also the chloromethyl group in the para position of the benzene ring can serve as an active site to react with methoxypolyethylene glycol to form a polyether long chain on its side chain. While the monomer MDO opens the ring during the polymerization process to form a main chain polyester structure, enabling the hyperbranched macromolecular polymer to have degradability and reducing the harm to the environment; the rich ester groups and polyethers have good lipophilicity and hydrophilicity, which can reduce the strength of the interfacial film, and the hyperbranched polymer chain and long side chain can quickly adsorb on the surface of the oil droplets to achieve the purpose of rapid demulsification and oil removal.

[0015] 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 with a main chain polyester and side chain polyether based on the SCVP-RAFT method and combined with the chlorine substitution method. It has characteristics such as a large molecular weight, a high degree of branching, a long molecular chain, and multiple aromatic rings. It has high universality, can rapidly demulsify different types of crude oil, has a small dosage of the demulsifier and is easily degradable, and can also reduce environmental pollution. Specific embodiments

[0016] 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 the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] Example: A hyperbranched multi-branched polyether demulsifier is prepared by the following preparation method:

[0019] S1. Add vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane (MDO) into a reaction flask, then add an organic solvent and stir to mix evenly. Bubble with an inert gas for 30 min, and then heat to 70-80 °C under the protection of the inert gas and react for 6-8 h;

[0020] S2. After the reaction is completed, remove the inert gas, cool to room temperature, add an organic solvent for dilution, add CTAB and methoxypolyethylene glycol (mPEG400-1000), add a certain amount of sodium hydroxide solution, heat to 70-80 °C and react overnight. After cooling to room temperature, add it to an anhydrous ether solution and filter and vacuum dry.

[0021] The raw materials used in the above reaction process can be purchased from the market without special instructions. Among them, the organic solvent is a mixed solution of toluene and N,N-dimethylformamide (DMF) with equal volume; the vinyl trithiocarbonate is prepared according to paragraphs [0026-0029] of the applicant's patent 2020110194314.

[0022]

[0023] Example 1:

[0024] 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. Bubble with argon for 30 min, and then heat to 80 °C under the protection of argon and react for 8 h;

[0025] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 30 mmol of mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0026] Example 2:

[0027] S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO to the reaction flask. Then add 10 ml of organic solvent and stir to mix evenly. Bubble with argon for 30 min, and then heat to 80 °C under argon protection and react for 8 h;

[0028] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 50 mmol of mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0029] Example 3:

[0030] S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 60 mmol of p-chloromethylstyrene and 40 mmol of MDO to the reaction flask. Then add 10 ml of organic solvent and stir to mix evenly. Bubble with argon for 30 min, and then heat to 80 °C under argon protection and react for 8 h;

[0031] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 60 mmol of mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0032] Example 4:

[0033] S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO to the reaction flask. Then add 10 ml of organic solvent and stir to mix evenly. Bubble with argon for 30 min, and then heat to 80 °C under argon protection and react for 8 h;

[0034] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 50 mmol of mPEG600, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0035] Example 5:

[0036] S1. Add 1 mmol of vinyl trithiocarbonate, 0.2 mmol of AIBN, 50 mmol of p-chloromethylstyrene and 50 mmol of MDO to a reaction flask. Then add 10 ml of organic solvent and stir to mix evenly. Bubble with argon for 30 min, and then heat to 80 °C under argon protection and react for 8 h.

[0037] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 50 mmol of mPEG1000, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0038] Comparative example:

[0039] S1. Add 0.2 mmol of AIBN, 60 mmol of p-chloromethylstyrene and 40 mmol of MDO to a reaction flask. Then add organic solvent and stir to mix evenly. Bubble with argon for 30 min, and then heat to 80 °C under argon protection and react for 8 h.

[0040] S2. After the reaction is completed, remove argon, cool to room temperature, add 40 ml of organic solvent for dilution, add a catalytic amount of CTAB and 30 mmol of mPEG400, add 40 g of 30 wt% sodium hydroxide solution, heat to 70 °C and react overnight. After cooling to room temperature, add it to anhydrous ether solution, filter and dry under vacuum.

[0041] Demulsifier performance test:

[0042] Use the demulsifier prepared above to evaluate the demulsification performance of Wei 5 crude oil in Jiangsu Oilfield. According to the industry standard SY-T5281-2000 Detection method for the use performance of crude oil demulsifiers, the water content of the oil sample is 46%, the detection temperature is 50 °C, and the detection results are recorded in Table 1.

[0043] Table 1

[0044]

[0045] As can be seen from the above table, in the present invention, a hyperbranched multi-branched polymer material with a main-chain polyester and a branched-chain polyether, prepared based on the SCVP-RAFT method in combination with the chlorine substitution method, can rapidly demulsify crude oil. By comparing Examples 1-3, it can be found that when the molar ratio of chloromethylstyrene to MDO is 1:1 during the polymerization process, the effect is better. The main-chain ester group formed by the ring-opening of MDO can increase the molecular spatial structure of the demulsifier, make the molecular chain longer, and the random copolymer formed with chloromethylstyrene can graft more polyether chains, reducing the surface tension of the crude oil emulsion, so the demulsification effect is good. By comparing Example 3 with Examples 4-5, it can be found that the larger the molecular weight of methoxypolyethylene glycol, the stronger the surface activity of the demulsifier. The demulsification performance of Examples 1-4 gradually increases with the increase of the demulsifier concentration and the extension of the demulsification time, but the change of Example 5 with the increase of concentration is not significant. Because the molecular chain of mPEG is longer and has higher hydrophilicity, micelles are formed after adsorption at the oil-water interface becomes supersaturated, and the dehydration rate no longer increases. In contrast, the polymer prepared in the comparative example is a linear multi-branched polymer, and the effect is not obvious when used as a demulsifier, and a better demulsification effect can only be obtained when the dosage is relatively high.

[0046] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated and described examples here.

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 anhydrous ether solution, filter and vacuum dry; The structural formula of the vinyl trithiocarbonate is ; The molar ratio of the vinyl trithiocarbonate, AIBN, p-chloromethylstyrene and 2-methylene-1,3-dioxepane is 1:0.2:30-60:40-70; 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.

2. 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.

3. The method for preparing a hyperbranched multi-branched polyether demulsifier according to claim 1, wherein The mass fraction of the sodium hydroxide solution is 30%.

4. A hyperbranched multi-branched polyether demulsifier prepared by the preparation method as described in any one of claims 1 to 3.

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