A silicone branched supercritical carbon dioxide thickener and a method for preparing the same

Abstract

The present application relates to oil-based drilling cuttings harmless treatment field, specifically, it relates to a kind of siloxane branched supercritical carbon dioxide thickening agent and its preparation method, and preparation raw material is: 2-allyl glyoxal, acetaldehyde, benzoic acid, triisopropoxy silane and trimethyl silicate.The supercritical carbon dioxide thickening agent provided in the present application has good solubility in supercritical carbon dioxide, has excellent thickening performance, can make the viscosity of supercritical carbon dioxide expand to 171 times, the average extraction rate of oil phase in oil-based drilling cuttings can reach 99.90%, and the cost is low, raw material is easy to obtain, and can realize scale application.

Description

Technical Field

[0001] The present invention relates to the field of harmless treatment of oil-based drill cuttings, and in particular to a supercritical carbon dioxide thickener and a preparation method thereof. Background Art

[0002] Oil-based drill cuttings are produced during the drilling process using oil-based drilling fluid. Oil-based drill cuttings are hazardous waste. To decontaminate them and collect the oil phase for recycling, pyrolysis is currently the most commonly used method. However, this method produces VOCs, causing secondary pollution, and it is difficult to meet local hazardous waste treatment standards. Supercritical fluid extraction is a clean, safe, and efficient separation technology. Extracting oil-based drill cuttings with supercritical carbon dioxide can effectively extract the oil phase from the cuttings, with good environmental, economic, and social benefits. However, supercritical carbon dioxide has a low viscosity, is easily dissipated during use, and the extraction effect is unstable. Therefore, it is necessary to solve the problem of low carbon dioxide viscosity and study supercritical carbon dioxide thickeners.

[0003] Current carbon dioxide thickeners can be roughly divided into three categories based on the elements contained in the active groups: (1) Fluorine-containing thickeners. Fluorine-containing compounds can dissolve well in supercritical carbon dioxide, allowing the thickener to better play a thickening role, but fluorine-containing compounds are expensive and pollute the environment. (2) Siloxane thickeners. Siloxane thickeners have poor solubility in supercritical carbon dioxide and often require the use of cosolvents, which are expensive. (3) Hydrocarbon and its derivative thickeners. The thickening effect of this type of thickener is also not ideal. For example, CN108003349B discloses a method for preparing a supercritical carbon dioxide thickener. The final product is a polymer containing silicone, phenyl and amide groups. This type of polymer has a certain thickening effect, but its thickening effect is still not significant. Therefore, it is an urgent problem to develop a supercritical carbon dioxide thickener with good solubility and thickening properties. Summary of the Invention

[0004] The present invention provides a supercritical carbon dioxide thickener and a preparation method thereof, which can effectively solve the above problems.

[0005] The first aspect of the present invention provides a method for preparing a supercritical carbon dioxide thickener, comprising the following steps:

[0006] S1. Add 2-allyl malondialdehyde (CAS No.: 861244-75-9) into a three-necked flask, then add acetaldehyde, and then add a 10% alkaline solution. Stir and react at 3-8° C. for 1-2 hours. After the reaction, fractionate and purify to obtain the product intermediate A. The molar ratio of acetaldehyde to 2-allyl malondialdehyde is (5-15):1.

[0007] S2. Add the intermediate A obtained in step S1 to a reaction vessel, then add thionyl chloride, and then dropwise add alcohol dissolved with benzoic acid, and stir at 20-30° C. for 2-4 hours. After the reaction, distill under reduced pressure, wash with water, and purify to obtain the intermediate B;

[0008] S3, dissolving the intermediate B obtained in step S2 in tetrahydrofuran, stirring and heating to 60-100° C., then adding chloroplatinic acid as a catalyst for activation for 1-3 hours, then adding triisopropoxysilane, and reacting under a nitrogen atmosphere at a temperature of 70-90° C. for 8-12 hours to perform a hydrosilylation reaction. After the reaction, distilling under reduced pressure, washing with water, and drying to obtain the intermediate C;

[0009] S4. Tetrahydrofuran was added to a three-necked flask, and then trimethyl silicate (CAS No.: 18230-57-4) was added, and the mixture was stirred at 20-30° C. to dissolve them mutually. Then, the intermediate C obtained in step S3 was added, and the mixture was heated and stirred under a nitrogen atmosphere. The reaction was carried out at a temperature of 160-190° C. for 2-4 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain the supercritical carbon dioxide thickener containing siloxane branches.

[0010] Wherein: the alkaline solution in step S1 is one of sodium hydroxide solution and potassium hydroxide solution.

[0011] The benzoic acid substance in step S2 is one of (4-methoxyphenyl)acetic acid (CAS No.: 104-01-8), 4-ethoxyphenylacetic acid (CAS No.: 4919-33-9), and 4-(1-methylethoxy)phenylacetic acid (CAS No.: 55784-07-1).

[0012] The alcohol in step S2 is one of methanol and ethanol.

[0013] The second aspect of the present invention provides a novel supercritical carbon dioxide thickener prepared by the above preparation method.

[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0015] The novel carbon dioxide thickener provided by the present invention has an ester group that improves its solubility in carbon dioxide, and the siloxane has good chain flexibility, which has a good thickening effect on supercritical carbon dioxide. The introduction of phenyl groups also improves its thickening effect. The present invention not only has a good thickening effect on supercritical carbon dioxide, but is also low in price and has readily available raw materials, making it suitable for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is one of the product structural formulas of the present invention.

[0017] Figure 2 It is one of the product structural formulas of the present invention.

[0018] Figure 3 It is one of the product structural formulas of the present invention. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Where specific conditions are not specified in the embodiments, the process shall be carried out under conventional conditions or the conditions recommended by the manufacturer. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work shall fall within the scope of protection of the present invention.

[0020] The embodiments of the present invention are as follows:

[0021] Example 1

[0022] S1. 16.82 g of 2-allylmalondialdehyde (CAS No.: 861244-75-9) was added to a three-necked flask, followed by 88.12 g of acetaldehyde. A 10% aqueous sodium hydroxide solution was then added dropwise to adjust the pH of the mixture to 8. The flask was placed in an ice-water bath and stirred at 5°C for 1 h. After completion of the reaction, the intermediate A was obtained by fractional distillation and purification.

[0023] S2. Add 332.38 g of (4-methoxyphenyl)acetic acid (CAS No.: 104-01-8) into a three-necked flask containing 50 mL of anhydrous methanol, then add 4 g of thionyl chloride, and then add 70 g of the intermediate A obtained in step S1. Stir and react at 25°C for 3 hours. After the reaction, evaporate under reduced pressure, wash with water, and purify to obtain the intermediate B.

[0024] S3. Dissolve 280 g of the intermediate B obtained in step S2 in tetrahydrofuran, stir and heat to 80 ° C, then add 4 g of chloroplatinic acid to activate for 2 hours, then add 20.64 g of triisopropoxysilane, and react under a nitrogen atmosphere while maintaining the temperature at 80 ° C for 10 hours to carry out a hydrosilylation reaction. After the reaction, distill under reduced pressure, wash with water, and dry to obtain the intermediate C.

[0025] S4. Tetrahydrofuran was added to a three-necked flask, followed by 41.47 g of trimethyl silicate (CAS No.: 18230-57-4), and the mixture was stirred at 25° C. to dissolve the mixture. 200 g of the intermediate C obtained in step S3 was then added, and the mixture was heated and stirred under a nitrogen atmosphere. The mixture was stirred and reacted at a temperature of 180° C. for 2 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain the supercritical carbon dioxide thickener containing siloxane side chains.

[0026] Example 2

[0027] S1. 16.82 g of 2-allylmalondialdehyde (CAS No.: 861244-75-9) was added to a three-necked flask, followed by 44.06 g of acetaldehyde. A 10% aqueous sodium hydroxide solution was then added dropwise to adjust the pH of the mixture to 8. The flask was placed in an ice-water bath and stirred at 5°C for 1 h. After completion of the reaction, the intermediate A was obtained by fractional distillation and purification.

[0028] S2. Add 332.38 g of (4-methoxyphenyl)acetic acid (CAS No.: 104-01-8) into a three-necked flask containing 50 mL of anhydrous ethanol, then add 4 g of thionyl chloride, and then add 40 g of the intermediate A obtained in step S1. Stir and react at 25°C for 3 hours. After the reaction, evaporate under reduced pressure, wash with water, and purify to obtain the intermediate B.

[0029] S3. Dissolve 250 g of the intermediate B obtained in step S2 in tetrahydrofuran, stir and heat to 80° C., then add 4 g of chloroplatinic acid to activate for 2 hours, then add 20.64 g of triisopropoxysilane, and react under a nitrogen atmosphere while maintaining the temperature at 80° C. for 10 hours to carry out a hydrosilylation reaction. After completion of the reaction, distill under reduced pressure, wash with water, and dry to obtain the intermediate C.

[0030] S4. Tetrahydrofuran was added to a three-necked flask, followed by 41.47 g of trimethyl silicate (CAS No.: 18230-57-4), and the mixture was stirred at 25°C to dissolve them. 180 g of the long-chain compound with silicon-oxygen bonds obtained in step S3 was then added, and the mixture was heated and stirred under a nitrogen atmosphere. The mixture was stirred and reacted at a temperature of 180°C for 2 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain the supercritical carbon dioxide thickener containing silicone branches.

[0031] Example 3

[0032] S1. 16.82 g of 2-allylmalondialdehyde (CAS No.: 861244-75-9) was added to a three-necked flask, followed by 88.12 g of acetaldehyde. A 10% aqueous sodium hydroxide solution was then added dropwise to adjust the pH of the mixture to 8. The flask was placed in an ice-water bath and stirred at 5°C for 1 h. After completion of the reaction, the intermediate A was obtained by fractional distillation and purification.

[0033] S2. Add 388.5 g of 4-(1-methylethoxy)phenylacetic acid (CAS No.: 55784-07-1) to a three-necked flask containing 50 mL of anhydrous methanol, then add 4 g of thionyl chloride, and then add 70 g of the intermediate A obtained in step S1. Stir and react at 25° C. for 3 hours. After the reaction, evaporate under reduced pressure, wash with water, and purify to obtain the intermediate B.

[0034] S3. 310 g of the intermediate B obtained in step S2 was dissolved in tetrahydrofuran, stirred and heated to 80° C., then 4 g of chloroplatinic acid was added for activation for 2 hours, and then 20.64 g of triisopropoxysilane was added thereto. Under a nitrogen atmosphere, the temperature was maintained at 80° C. for 10 hours to carry out a hydrosilylation reaction. After completion of the reaction, the mixture was distilled under reduced pressure, washed with water, and dried to obtain the intermediate C.

[0035] S4. Tetrahydrofuran was added to a three-necked flask, followed by 41.47 g of trimethyl silicate (CAS No.: 18230-57-4), and the mixture was stirred at 25°C to dissolve the mixture. 230 g of the intermediate C obtained in step S3 was then added, and the mixture was heated and stirred under a nitrogen atmosphere. The mixture was stirred and reacted at a temperature of 180°C for 2 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain the supercritical carbon dioxide thickener containing siloxane side chains.

[0036] Example 4

[0037] S1. 16.821 g of 2-allylmalondialdehyde (CAS No.: 861244-75-9) was added to a three-necked flask, followed by 88.12 g of acetaldehyde. A 10% aqueous sodium hydroxide solution was then added dropwise to adjust the pH of the mixture to 8. The flask was placed in an ice-water bath and stirred at 5°C for 1 h. After completion of the reaction, the intermediate A was obtained by fractional distillation and purification.

[0038] S2. Add 228.22 g of 4-ethoxyphenylacetic acid (CAS No.: 4919-33-9) to a three-necked flask containing 50 mL of anhydrous ethanol, then add 4 g of thionyl chloride, and then add 70 g of the intermediate A obtained in step S1. Stir and react at 25° C. for 3 hours. After the reaction, evaporate under reduced pressure, wash with water, and purify to obtain the intermediate B.

[0039] S3. Dissolve 200 g of the intermediate B obtained in step S2 in tetrahydrofuran, stir and heat to 80 ° C, then add 4 g of chloroplatinic acid to activate for 2 hours, then add 20.64 g of triisopropoxysilane, and react under a nitrogen atmosphere while maintaining the temperature at 80 ° C for 10 hours to carry out a hydrosilylation reaction. After the reaction, distill under reduced pressure, wash with water, and dry to obtain the intermediate C.

[0040] S4. Tetrahydrofuran was added to a three-necked flask, followed by 41.47 g of trimethyl silicate (CAS No.: 18230-57-4), and the mixture was stirred at 25° C. to dissolve the mixture. 150 g of the intermediate C obtained in step S3 was then added, and the mixture was heated and stirred under a nitrogen atmosphere. The mixture was stirred and reacted at a temperature of 180° C. for 2 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with ethanol, and dried to obtain the supercritical carbon dioxide thickener containing siloxane branches.

[0041] Comparative Example 1

[0042] Comparative Example 1 is polydimethylsiloxane purchased from Beijing Bailingwei Technology Co., Ltd.

[0043] The final products of Examples 1 to 4 and Comparative Example 1 were added to supercritical carbon dioxide at a mass volume ratio of 1%, 2%, 3%, and 4%, respectively (for example, 1 g, 2 g, 3 g, and 4 g of thickener were added to 100 mL of supercritical carbon dioxide, respectively). The viscosity was tested using a VISCOlab PVT viscometer at 35° C. and 10 MPa. The viscosity ratio (compared to pure supercritical carbon dioxide) data is shown in Table 1.

[0044] As can be seen from Table 1, the present invention has a significant thickening effect. When the mass volume ratio is 3%, a good thickening effect can be achieved, which can be up to 171 times compared to pure supercritical carbon dioxide. Under the same test conditions, the viscosity ratios of Examples 1-4 are significantly higher than those of the comparative examples, indicating that the present invention has a good thickening ability for supercritical carbon dioxide. Under the same test conditions, the viscosity ratio of Example 2 is lower than that of the other examples, indicating that the thickening effect of the thickener on supercritical carbon dioxide is affected by the degree of polymerization. As the mass volume ratio of the thickener to supercritical carbon dioxide increases from 1% to 3%, the thickening effect is significantly improved. When the mass volume ratio is increased to 4%, the thickening effect does not change significantly. Example 1 is the best embodiment of the present invention.

[0045] Table 1 Thickening effect evaluation results

[0046]

[0047]

[0048] The final products of Examples 1 to 4 and Comparative Example 1 were mixed with supercritical carbon dioxide at a mass volume ratio of 1%, 2%, 3%, and 4% (for example, 1 g, 2 g, 3 g, and 4 g of thickener were added to every 100 mL of supercritical carbon dioxide). At 35° C. and 10 MPa, each mixture was subjected to three supercritical carbon dioxide extraction experiments on oil-based drill cuttings in a reactor. The average extraction rate data are shown in Table 2.

[0049] As can be seen from Table 2, the present invention has a significant extraction effect, and the average extraction rate can reach 99.90%. Under the same test conditions, the extraction effects of Examples 1-4 are significantly higher than those of the comparative example, indicating that the present invention has good extraction capabilities for the oil phase in oil-based drill cuttings. A very good extraction effect can be achieved when the mass volume ratio is added at 3%. As the mass volume ratio of the thickener to supercritical carbon dioxide increases from 1% to 3%, the extraction rate increases significantly, and when the mass volume ratio increases to 4%, the extraction rate does not change significantly. The improvement in the extraction effect also reflects that the thickening effect of the present invention is significant. Example 1 is the best embodiment of the present invention.

[0050] Table 2 Extraction effect evaluation results

[0051]

[0052]

[0053] In summary, the present invention has a significant thickening effect. The viscosity of relatively pure supercritical carbon dioxide can reach 171 times, and the average extraction rate of the oil phase in oil-based drill cuttings can reach 99.90%, which can meet local hazardous waste treatment standards. Compared with the pyrolysis method, it has obvious technical advantages, is safe, efficient, environmentally friendly, low-cost, and can be applied on a large scale.

[0054] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modification, equivalent change, and modification made by any technician familiar with the present profession to the above embodiment based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a supercritical carbon dioxide thickener containing siloxane branches, characterized in that: The raw materials of the material are mainly: 2-allyl malondialdehyde, acetaldehyde, benzoic acid, triisopropoxysilane, and trimethyl silicate. The preparation includes the following steps: S1. Add 10-20 mole parts of 2-allyl malondialdehyde (CAS No.: 861244-75-9) to a three-necked flask, then add 100-250 mole parts of acetaldehyde, and then add a 10% alkaline solution. Stir and react at 3-8°C for 1-2 hours. After the reaction, fractionate and purify to obtain the product intermediate A. The molar ratio of acetaldehyde to 2-allyl malondialdehyde is (5-15):

1. S2. Add the intermediate A obtained in step S1 to a reaction vessel, then add thionyl chloride, and then dropwise add 100-250 mol parts of alcohol containing benzoic acid, and stir at 20-30° C. for 2-4 hours. After the reaction, distill under reduced pressure, wash with water, and purify to obtain the intermediate B. S3, dissolving the intermediate B obtained in step S2 in tetrahydrofuran, stirring and heating to 60-100° C., then adding chloroplatinic acid as a catalyst for activation for 1-3 hours, then adding 5-15 mol parts of triisopropoxysilane, and reacting under a nitrogen atmosphere at a temperature of 70-90° C. for 8-12 hours to carry out a hydrosilylation reaction. After the reaction, distilling under reduced pressure, washing with water, and drying to obtain the intermediate C; S4. Add tetrahydrofuran to a three-necked flask, then add 20-40 molar parts of trimethyl silicate (CAS No.: 18230-57-4), stir at 20-30° C. to dissolve them, then add the intermediate C obtained in step S3, heat and stir under a nitrogen atmosphere, and react at a temperature of 160-190° C. for 2-4 hours. After the reaction is completed, distill under reduced pressure, wash with ethanol, and dry to obtain the supercritical carbon dioxide thickener containing siloxane branches; The benzoic acid substance in step S2 is one of (4-methoxyphenyl)acetic acid (CAS No.: 104-01-8), 4-ethoxyphenylacetic acid (CAS No.: 4919-33-9), and 4-(1-methylethoxy)phenylacetic acid (CAS No.: 55784-07-1).

2. The method for preparing a carbon dioxide thickener according to claim 1, wherein The alkaline solution in step S1 is one of sodium hydroxide solution and potassium hydroxide solution.

3. The method for preparing a carbon dioxide thickener according to claim 1, wherein: The alcohol in step S2 is one of methanol and ethanol.

4. A supercritical carbon dioxide thickener prepared by the method for preparing a carbon dioxide thickener according to any one of claims 1 to 3.

Images