Cyclodextrin ionic liquid demulsifier and preparation method thereof

Abstract

The invention provides a cyclodextrin ionic liquid demulsifier and a preparation method thereof. The demulsifier takes cyclodextrin as a core, and the surface of the demulsifier is grafted with tertiary amine with long-chain alkane through chloroacetyl chloride. The preparation method comprises the following steps: S1, modifying cyclodextrin with chloroacetyl chloride to obtain chloroacetyl chloride modified cyclodextrin; and S2, grafting chloroacetyl chloride modified cyclodextrin by using tertiary amine with long-chain alkane to obtain the cyclodextrin ionic liquid demulsifying agent. The demulsifier has the characteristics of low amount, high efficiency, easiness in degradation, salt resistance, acid resistance, alkali resistance and the like, and has a good demulsification effect on oil-containing wastewater and high oil removal rate.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction and oilfield processing, and particularly relates to a cyclodextrin ionic liquid demulsifier and a preparation method thereof. Background Art

[0002] Increasing concerns about environmental safety have promoted the continuous improvement of waste treatment technologies and the development of new materials, which should meet the requirements for the quality of discharged water in various industrial fields. Oily waste is not only one of the major challenges in the oil and petrochemical industries, but also one of the major challenges in food, cosmetics, and pharmaceutical production. Although the qualitative and quantitative compositions of oily waste may vary depending on the industrial field, most of the oil always exists in an emulsified form and is ultimately often difficult to separate from the aqueous phase. Due to the very large negative impact of emulsified oil on mechanical, membrane separation, adsorption, filtration, and demulsification efficiency, demulsification of oil-in-water emulsions remains a key step in most oily waste treatment technology devices.

[0003] Currently, the raw materials of commonly used commercial demulsifiers are all petrochemical products, with high raw material costs, complex synthesis processes, and with the development of crude oil extraction technologies, existing commercial demulsifiers cannot meet the current operation requirements, and there are problems such as low demulsification efficiency and high oil content in the separated aqueous phase. Summary of the Invention

[0004] To solve the problems in the background art, the present invention provides a cyclodextrin ionic liquid demulsifier and a preparation method thereof. The cyclodextrin ionic liquid demulsifier has excellent interfacial activity and a high oil removal rate when used for demulsifying oily wastewater.

[0005] The technical solution of the present invention for solving the above technical problems is as follows:

[0006] In the first aspect, the present invention provides a cyclodextrin ionic liquid demulsifier, wherein the demulsifier takes cyclodextrin as the core, and a tertiary amine with a long-chain alkyl group is grafted on the surface through chloroacetyl chloride.

[0007] In the second aspect, the present invention provides a preparation method of the above cyclodextrin ionic liquid demulsifier, including the following steps:

[0008] S1. Modify cyclodextrin with chloroacetyl chloride to obtain chloroacetyl chloride-modified cyclodextrin;

[0009] S2. Graft the chloroacetyl chloride-modified cyclodextrin with a tertiary amine having a long-chain alkane to obtain the cyclodextrin ionic liquid demulsifier.

[0010] According to the above solution, step S1 is specifically: adding cyclodextrin to solvent I and mixing evenly, adding chloroacetyl chloride and reacting at room temperature for 10 - 24 h, and then precipitating with solvent II to obtain chloroacetyl chloride-modified cyclodextrin.

[0011] According to the above scheme, in step S1, the mass ratio of cyclodextrin to chloroacetyl chloride is 1:(1 - 5), the mass ratio of the cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):1.

[0012] According to the above scheme, step S2 is specifically as follows: adding the chloroacetyl chloride-modified cyclodextrin into solvent I and mixing evenly, adding a tertiary amine with a long-chain alkyl group, reacting at 100 - 150 °C for 10 - 24 h, and then precipitating with solvent II to obtain the cyclodextrin ionic liquid demulsifier.

[0013] According to the above scheme, the mass ratio of the tertiary amine with a long-chain alkyl group to cyclodextrin is (2 - 10):1, the mass ratio of the chloroacetyl chloride-modified cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):1.

[0014] According to the above scheme, solvent I is one or more of water, N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0015] According to the above scheme, solvent II is one or more of methanol, ethanol, ether, acetone, and tetrahydrofuran.

[0016] According to the above scheme, the cyclodextrin is one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0017] According to the above scheme, the tertiary amine with a long-chain alkyl group is one or more of dodecyldiethanolamine, N,N-dimethyldodecylamine, tetradecyldimethylamine, N,N-dimethyl-n-octylamine, octadecyldimethylamine, and octadecyldiethanolamine.

[0018] The beneficial effects of the present invention are as follows:

[0019] In the present invention, first, a small molecule chloroacetyl chloride is used as a bridging group to graft onto cyclodextrin, and then it reacts with a tertiary amine with a long-chain alkyl group to obtain a cyclodextrin ionic liquid demulsifier with cyclodextrin as the core, a quaternary ammonium salt in the middle, and a hydrophobic long-chain alkyl group on the outermost layer; this cyclodextrin ionic liquid demulsifier has amphiphilicity and excellent surface and interfacial activity, and it can quickly diffuse in the continuous aqueous phase and adsorb onto the oil-water interface, interact with the natural active component asphaltene on the interfacial film and displace the original natural active component asphaltene on the interfacial film, greatly reducing the oil-water interfacial tension, weakening the stability of the interfacial film, and inducing demulsification; in addition, the cyclodextrin ionic liquid demulsifier of the present invention has a positive charge, which can further enhance the interaction between the cyclodextrin ionic liquid demulsifier and the interfacial film through electrostatic neutralization, reduce the stability of the interfacial film, and promote the occurrence of the demulsification process;

[0020] The cyclodextrin ionic liquid demulsifier of the present invention has the characteristics of low dosage and high efficiency, easy degradation, salt resistance, acid and alkali resistance, etc. When it is used for demulsifying oily wastewater, it has a high oil removal rate. Under the condition of pH value ranging from 3 to 11, the oil removal rate of oily wastewater is above 97%. Under the high salt condition of 25 g / L, the oil removal rate of wastewater with an oil content of 1% is as high as 99%. It has excellent demulsification effect under extreme conditions such as acid, alkali and high salt. Detailed implementation manners

[0021] The principles and features of the present invention will be described below in conjunction with specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0022] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the range.

[0023] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. The reagents not specifically described in detail in this application are all conventional reagents and can be obtained commercially; the methods not specifically described in detail are all conventional experimental methods and can be known from the prior art.

[0024] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of this application are only exemplary.

[0025] The present invention provides a cyclodextrin ionic liquid demulsifier, which takes cyclodextrin as the core, and a tertiary amine with a long-chain alkyl group is grafted on the surface through chloroacetyl chloride.

[0026] The present invention provides a preparation method of the above-mentioned cyclodextrin ionic liquid demulsifier, which includes the following steps:

[0027] S1. Modify cyclodextrin with chloroacetyl chloride to obtain chloroacetyl chloride-modified cyclodextrin;

[0028] S2. Graft the chloroacetyl chloride-modified cyclodextrin with a tertiary amine having a long-chain alkane to obtain the cyclodextrin ionic liquid demulsifier.

[0029] First, use small molecule chloroacetyl chloride as a bridging group to graft onto cyclodextrin, and then react with a tertiary amine having a long-chain alkyl group to obtain a cyclodextrin ionic liquid demulsifier with cyclodextrin as the core, a quaternary ammonium salt in the middle, and a long-chain alkyl group on the outermost layer. The long-chain alkyl group on the outermost layer provides a hydrophobic chain, enabling it to interact with the natural active components at the interface. At the same time, the cyclodextrin ionic liquid demulsifier has a positive charge, which can further enhance the interaction between the cyclodextrin ionic liquid demulsifier and the interfacial film through electrostatic neutralization, reduce the interfacial film stability, and promote the occurrence of the demulsification process.

[0030] Preferably, step S1 is specifically: adding cyclodextrin to solvent I and mixing evenly, adding chloroacetyl chloride, reacting at room temperature for 10 - 24 h, and then precipitating with solvent II to obtain chloroacetyl chloride-modified cyclodextrin.

[0031] Preferably, in step S1, the mass ratio of cyclodextrin to chloroacetyl chloride is 1:(1 - 5), the mass ratio of cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):1.

[0032] Preferably, step S2 is specifically: adding chloroacetyl chloride-modified cyclodextrin to solvent I and mixing evenly, adding a tertiary amine having a long-chain alkyl group, reacting at 100 - 150 °C for 10 - 24 h, and then precipitating with solvent II to obtain a cyclodextrin ionic liquid demulsifier.

[0033] Preferably, the mass ratio of the tertiary amine having a long-chain alkyl group to cyclodextrin is (2 - 10):1, the mass ratio of chloroacetyl chloride-modified cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):1.

[0034] In some preferred embodiments, the solvent I is one or more of water, N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0035] In some preferred embodiments, the solvent II is one or more of methanol, ethanol, ether, acetone, and tetrahydrofuran.

[0036] Preferably, the cyclodextrin is one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0037] In some preferred embodiments, the tertiary amine having a long-chain alkyl group is one or more of dodecyl diethanolamine, N,N-dimethyldodecylamine, tetradecyl dimethyl tertiary amine, N,N-dimethyl n-octylamine, octadecyl dimethyl tertiary amine, and octadecyl diethanolamine.

[0038] The following further illustrates the invention through specific examples.

[0039] Example 1

[0040] This example provides a cyclodextrin ionic liquid demulsifier, which is obtained through the following steps:

[0041] Add 1 g of β-cyclodextrin to 50 mL of N,N-dimethylformamide. After mixing evenly, add 3 g of chloroacetyl chloride. React at room temperature for 24 h, and then precipitate the product with acetone to obtain chloroacetyl chloride-modified cyclodextrin. Add 1 g of chloroacetyl chloride-modified cyclodextrin to 50 mL of N,N-dimethylformamide. After mixing evenly, add 6 g of dodecyldiethanolamine. React at 130 °C for 15 h, and then precipitate the product with acetone to obtain the cyclodextrin ionic liquid demulsifier.

[0042] The connection mode of the tertiary amine with a long-chain alkyl group and the chloroacetyl chloride-modified cyclodextrin in the prepared cyclodextrin ionic liquid demulsifier is as follows, but not all grafting sites on the cyclodextrin are marked.

[0043]

[0044] Example 2

[0045] This example provides a cyclodextrin ionic liquid demulsifier, which is obtained through the following steps:

[0046] Add 1 g of β-cyclodextrin to 50 mL of N,N-dimethylformamide. After mixing evenly, add 3 g of chloroacetyl chloride. React at room temperature for 24 h, and then precipitate the product with acetone to obtain chloroacetyl chloride-modified cyclodextrin. Add 1 g of chloroacetyl chloride-modified cyclodextrin to 50 mL of N,N-dimethylformamide. After mixing evenly, add 6 g of N,N-dimethyldodecylamine. React at 130 °C for 15 h, and then precipitate the product with acetone to obtain the cyclodextrin ionic liquid demulsifier.

[0047] The connection mode of the tertiary amine with a long-chain alkyl group and the chloroacetyl chloride-modified cyclodextrin in the prepared cyclodextrin ionic liquid demulsifier is as follows, but not all grafting sites on the cyclodextrin are marked.

[0048]

[0049] Example 3

[0050] This example provides a cyclodextrin ionic liquid demulsifier, which is obtained through the following steps:

[0051] 1 g of β-cyclodextrin was added to 50 mL of N,N-dimethylformamide. After mixing evenly, 3 g of chloroacetyl chloride was added. After reacting at room temperature for 24 h, the product was precipitated with acetone to obtain chloroacetyl chloride-modified cyclodextrin. 1 g of chloroacetyl chloride-modified cyclodextrin was added to 50 mL of N,N-dimethylformamide. After mixing evenly, 6 g of octadecyl diethanolamine was added. After reacting at 130 °C for 15 h, the product was precipitated with acetone to obtain a cyclodextrin ionic liquid demulsifier.

[0052] In the prepared cyclodextrin ionic liquid demulsifier, the connection mode of the tertiary amine with a long-chain alkyl group and the chloroacetyl chloride-modified cyclodextrin is as follows, but not all grafting sites on the cyclodextrin are marked.

[0053]

[0054] Example 4

[0055] This example provides a cyclodextrin ionic liquid demulsifier, which is obtained through the following steps:

[0056] 1 g of β-cyclodextrin was added to 50 mL of N-methylpyrrolidone. After mixing evenly, 3 g of chloroacetyl chloride was added. After reacting at room temperature for 24 h, the product was precipitated with ether to obtain chloroacetyl chloride-modified cyclodextrin. 1 g of chloroacetyl chloride-modified cyclodextrin was added to 50 mL of N-methylpyrrolidone. After mixing evenly, 6 g of octadecyl dimethyl tertiary amine was added. After reacting at 130 °C for 15 h, the product was precipitated with ether to obtain a cyclodextrin ionic liquid demulsifier.

[0057] Example 5

[0058] This example provides a cyclodextrin ionic liquid demulsifier, which is obtained through the following steps:

[0059] 1 g of β-cyclodextrin was added to 50 mL of N-methylpyrrolidone. After mixing evenly, 3 g of chloroacetyl chloride was added. After reacting at room temperature for 24 h, the product was precipitated with ether to obtain chloroacetyl chloride-modified cyclodextrin. 1 g of chloroacetyl chloride-modified cyclodextrin was added to 50 mL of N-methylpyrrolidone. After mixing evenly, 6 g of N,N-dimethyl n-octylamine was added. After reacting at 130 °C for 15 h, the product was precipitated with ether to obtain a cyclodextrin ionic liquid demulsifier.

[0060] Performance test

[0061] The cyclodextrin ionic liquid demulsifiers prepared in Examples 1-5 were used for oily wastewater to determine their demulsification performance.

[0062] Test Example 1

[0063] Add 5 parts by weight of crude oil to 495 parts by weight of water, heat to 60 °C, and then stir at a speed of 11000 r / min for 20 min to obtain stable oily wastewater.

[0064] Add the cyclodextrin ionic liquid demulsifier prepared in Examples 1-5 to water to prepare a cyclodextrin ionic liquid demulsifier solution with a mass fraction of 0.2%. Add 1 volume part of the above cyclodextrin ionic liquid demulsifier solution to 20 volume parts of the oily wastewater emulsion respectively, then shake well and mix evenly, and then let it stand at room temperature for 30 min. Measure its light transmittance and measure the oil removal rate according to the regulations in the reference standard SY / T0530-2011 "Spectrophotometric Method for Determination of Oil Content in Produced Water from Oilfields". The results are shown in Table 1.

[0065] Table 1 Demulsification effects of Examples 1-5

[0066]

[0067]

[0068] As can be seen from the above table, the cyclodextrin ionic liquid demulsifier has a high demulsification efficiency in oily wastewater, with a high light transmittance of the separated water phase and a high oil removal rate.

[0069] Test Example 2

[0070] Add 5 parts by weight of crude oil to 495 parts by weight of water, heat to 60 °C, and then stir at a speed of 11000 r / min for 20 min to obtain stable oily wastewater.

[0071] Add different parts by weight of the cyclodextrin ionic liquid demulsifier prepared in Example 1 to water to prepare cyclodextrin ionic liquid demulsifier solutions with mass fractions of 0.2%, 0.15%, 0.1%, 0.05%, and 0% respectively. The obtained samples are denoted as groups 1-4; the blank group is water, and the sample is denoted as group 5.

[0072] Add 1 volume part of the above cyclodextrin ionic liquid demulsifier solution to 20 volume parts of the oily wastewater emulsion respectively, then shake well and mix evenly, and then let it stand at room temperature for 30 min. Measure its light transmittance and measure the oil removal rate according to the regulations in the reference standard SY / T0530-2011 "Spectrophotometric Method for Determination of Oil Content in Produced Water from Oilfields". The results are shown in Table 2.

[0073] Table 2 Effects of cyclodextrin ionic liquid demulsifier at different concentrations

[0074]

[0075] As can be seen from Table 2, the cyclodextrin ionic liquid demulsifier provided by the present invention has good demulsification performance. When using the cyclodextrin ionic liquid demulsifier with a concentration of 100 mg / L, after sedimentation at room temperature for 30 min, the light transmittance of the separated aqueous phase can reach 94.5%, and the oil removal rate is 99.88%.

[0076] Test Example 3

[0077] Add 5 parts by weight of crude oil to 495 parts by weight of water, adjust the pH value by adding hydrochloric acid or sodium hydroxide, heat to 60 °C, and then stir at a speed of 11,000 r / min for 20 min to obtain stable oily wastewater.

[0078] Add the cyclodextrin ionic liquid demulsifier prepared in Example 1 to water to prepare a cyclodextrin ionic liquid demulsifier solution with a mass fraction of 0.2% respectively.

[0079] Add 1 volume part of the above cyclodextrin ionic liquid demulsifier solution to 20 volume parts of oily wastewater emulsions with different pH values, then fully shake and mix evenly, and then place at room temperature for 30 min. Measure its light transmittance and measure the oil removal rate according to the regulations in the reference standard SY / T 0530-2011 "Spectrophotometric Method for Determination of Oil Content in Produced Water from Oilfields". The results are shown in Table 3.

[0080] Table 3 Effects of cyclodextrin ionic liquid demulsifier at different pH values

[0081]

[0082] As can be seen from Table 3: The cyclodextrin ionic liquid demulsifier provided by the present invention has a high demulsification efficiency under acidic or alkaline conditions.

[0083] Test Example 4

[0084] Add 5 parts by weight of crude oil to 495 parts by weight of water, adjust the salinity by adding sodium chloride, heat to 60 °C, and then stir at a speed of 11,000 r / min for 20 min to obtain stable oily wastewater.

[0085] Add the cyclodextrin ionic liquid demulsifier prepared in Example 1 to water to prepare a cyclodextrin ionic liquid demulsifier solution with a mass fraction of 0.2%.

[0086] Add 1 volume part of the above cyclodextrin ionic liquid demulsifier solution to 20 volume parts of the experimental groups 16-21 respectively, then fully shake and mix evenly, and then place at room temperature for 30 min. Measure its light transmittance and measure the oil removal rate according to the regulations in the reference standard SY / T 0530-2011 "Spectrophotometric Method for Determination of Oil Content in Produced Water from Oilfields". The results are shown in Table 4.

[0087] Table 4 Emulsifying demulsifier effect of cyclodextrin ionic liquid under different salt concentrations

[0088]

[0089]

[0090] As can be seen from Table 4, the emulsifying demulsifier of cyclodextrin ionic liquid provided by the present invention has a very high demulsification efficiency under high salinity conditions, indicating that the demulsifier has high salt resistance.

[0091] Therefore, the emulsifying demulsifier of cyclodextrin ionic liquid provided by the present invention has the characteristics of low dosage and high efficiency, easy degradation, salt resistance, acid and alkali resistance, etc.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cyclodextrin ionic liquid demulsifier, characterized in that, The demulsifier has cyclodextrin as the core, and a tertiary amine with a long-chain alkyl group is grafted on the surface through chloroacetyl chloride.

2. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 1, characterized in that, It includes the following steps: S1. Modify cyclodextrin with chloroacetyl chloride to obtain chloroacetyl chloride-modified cyclodextrin. S2. Graft the chloroacetyl chloride-modified cyclodextrin with a tertiary amine having a long-chain alkane to obtain the cyclodextrin ionic liquid demulsifier.

3. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 2, characterized in that, Step S1 is specifically: Add cyclodextrin to solvent I and mix evenly, add chloroacetyl chloride and react at room temperature for 10 - 24 h, then precipitate with solvent II to obtain chloroacetyl chloride-modified cyclodextrin.

4. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 3, characterized in that, The mass ratio of the cyclodextrin to the chloroacetyl chloride is 1:(1 - 5), the mass ratio of the cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):

1.

5. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 2, characterized in that, Step S2 is specifically: Add the chloroacetyl chloride-modified cyclodextrin to solvent I and mix evenly, add a tertiary amine having a long-chain alkyl group, react at 100 - 150 °C for 10 - 24 h, then precipitate with solvent II to obtain the cyclodextrin ionic liquid demulsifier.

6. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 5, characterized in that, The mass ratio of the tertiary amine having a long-chain alkyl group to the cyclodextrin is (2 - 10):1, the mass ratio of the chloroacetyl chloride-modified cyclodextrin to solvent I is 1:(50 - 100), and the mass ratio of solvent II to solvent I is (0.5 - 1):

1.

7. The preparation method of the cyclodextrin ionic liquid demulsifier according to any one of claims 3 to 6, characterized in that, The solvent I is one or more of water, N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

8. The preparation method of the cyclodextrin ionic liquid demulsifier according to any one of claims 3 to 6, characterized in that, The solvent II is one or more of methanol, ethanol, ether, acetone, and tetrahydrofuran.

9. The preparation method of the cyclodextrin ionic liquid demulsifier according to any one of claims 2 to 6, characterized in that, The cyclodextrin is one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

10. The preparation method of the cyclodextrin ionic liquid demulsifier according to claim 9, characterized in that, The tertiary amine having a long-chain alkyl group is one or more of dodecyldiethanolamine, N,N-dimethyldodecylamine, tetradecyldimethylamine, N,N-dimethyl-n-octylamine, octadecyldimethylamine, and octadecyldiethanolamine.

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