Peracetylated polysaccharide derivative mixing accelerator as well as preparation method and application thereof

Abstract

The invention discloses a peracetylated polysaccharide derivative mixing accelerator as well as a preparation method and application thereof, and relates to the technical field of polysaccharide derivatives. Alkyl polyglucoside and glycidyl ether are subjected to etherification reaction to obtain polysaccharide derivatives; and adding acetic anhydride and an organic weak base catalyst into the polysaccharide derivative, and carrying out esterification reaction to obtain the peracetylated polysaccharide derivative. The obtained peracetylated polysaccharide derivative can be used for reducing the minimum miscible pressure of CO2 in an offshore oilfield. The polysaccharide derivative provided by the invention is simple in synthesis process, and the molecular activity of the polysaccharide derivative can be regulated and controlled by changing the number of carbon dioxide-philic groups and the length of oleophylic unsaturated hydrocarbon chains, so that the polysaccharide derivative can be used in the CO2 oil displacement process of oilfield exploitation, and the minimum miscible pressure in the CO2 oil displacement process is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of polysaccharide derivatives technology, and in particular to a fully acetylated polysaccharide derivative mixing accelerator, its preparation method, and its application. Background Technology

[0002] In recent years, with increasing emphasis on the development and utilization of biomass resources, the demand for high-performance and environmentally friendly functional materials has been growing. Polysaccharides, as an important component of natural renewable resources, have attracted much attention due to their wide availability and good biocompatibility. Preparing derivatives of natural polysaccharides through chemical modification has become a key research direction for expanding their functions and applications. For example, traditional polysaccharide derivatives such as sodium alginate and chitosan mainly acquire specific properties through modification of hydroxyl or amino groups. However, their molecular structures usually depend on the inherent linear or network framework of natural polysaccharides. This inherent characteristic limits their ability to precisely regulate complex interfacial behavior, especially under harsh environments requiring the synergistic regulation of multiple interfacial interactions.

[0003] Against this backdrop, innovative design of molecular structures has become the core of overcoming existing technological bottlenecks. Although existing polysaccharide-based surfactants have improved surface activity to some extent through hydrophobic chain modification, their single-chain structures have inherent limitations in molecular configuration: on the one hand, the simple combination of a single hydrophobic chain and hydrophilic groups results in insufficient interfacial arrangement density, reducing the mechanical strength of the interfacial film; on the other hand, this one-dimensional linear structure makes it difficult to achieve the synergistic effect of multifunctional groups, resulting in significant deficiencies in interfacial stability and functional integration. Summary of the Invention

[0004] In order to overcome the above-mentioned problems in the prior art, the present invention proposes a fully acetylated polysaccharide derivative mixing agent, its preparation method and application.

[0005] The technical solution adopted by this invention to solve its technical problem is: a fully acetylated polysaccharide derivative mixing agent, formed by glycidyl ether linking to alkyl polysaccharide glycoside and then fully acetylated, with the following general structural formula:

[0006] Where m takes the value of 1-2.5; n takes the value of 2-6; R1 is selected from any one of the straight-chain or branched alkyl groups with 8-14 carbon atoms.

[0007] A method for preparing a fully acetylated polysaccharide derivative blending agent, used to prepare the aforementioned fully acetylated polysaccharide derivative blending agent, specifically includes the following steps: Step 1: Place alkyl polysaccharide and inorganic strong base catalyst in a reactor and stir at 25°C for 1 hour. Then, heat the system to 60°C and slowly add the uniformly mixed glycidyl ether and isopropanol dropwise into the reaction system while stirring. The etherification reaction yields polysaccharide derivatives. Step 2: Acetic anhydride and the polysaccharide derivative obtained in Step 1 are placed in a reactor at a molar ratio of (8.00-10.00):1.00. Then, an organic weak base catalyst, a dehydrating agent, and an acyl transfer accelerator are added. Under a nitrogen atmosphere, the reaction system is stirred at 0°C for 1 hour. Then, the temperature is raised to 60°C to continue the esterification reaction, and finally, a fully acetylated polysaccharide derivative is obtained.

[0008] In the preparation method of the above-mentioned fully acetylated polysaccharide derivative mixing agent, the molar ratio of alkyl polysaccharide glycoside to glycidyl ether in step 1 is (2.00–2.50):1.00.

[0009] In the above-mentioned method for preparing a fully acetylated polysaccharide derivative blending agent, the amount of inorganic strong base catalyst used in step 1 is 2.00%–2.50% of the mass of the alkyl polysaccharide glycoside.

[0010] In the above-mentioned method for preparing a fully acetylated polysaccharide derivative blending agent, the amount of organic weak base catalyst used in step 2 is 2.00%-2.50% of the mass of the polysaccharide derivative.

[0011] In the above-mentioned method for preparing a fully acetylated polysaccharide derivative mixing agent, the inorganic strong base is selected from any one or more of sodium hydroxide, potassium hydroxide, sodium hydride, calcium hydroxide, and anhydrous sodium carbonate; the organic weak base is selected from any one or more of pyridine, triethylamine, diisopropylethylamine, 2,6-dimethylpyridine, and N-methylmorpholine.

[0012] The above-mentioned method for preparing a fully acetylated polysaccharide derivative mixing agent, wherein the alkyl polysaccharide is selected from any one or more alkyl glycosides having 8-14 carbon atoms.

[0013] The above-mentioned method for preparing a fully acetylated polysaccharide derivative mixing accelerator, wherein the dehydrating agent is selected from any one or more of silica gel, molecular sieve, activated carbon, and anhydrous sodium sulfate; and the acyl transfer accelerator is selected from any one or more of 4-dimethylaminopyridine, 4-pyrrolidinylpyridine, N-methylimidazolium, and triazole ionic liquids.

[0014] An application of a fully acetylated polysaccharide derivative blending agent in reducing the minimum miscibility pressure of CO2 in offshore oil fields, using a fully acetylated polysaccharide derivative blending agent as described above or a fully acetylated polysaccharide derivative blending agent prepared based on the above preparation method.

[0015] The above application is characterized in that the concentration of the fully acetylated polysaccharide derivative blending agent used for demixing is 0.3wt%-1.5wt%.

[0016] The beneficial effects of this invention are that it provides a fully acetylated polysaccharide derivative, which covalently links two alkyl polysaccharide units through a glycidyl ether linking group, constructing a novel molecule with a "polysaccharide-linking group-polysaccharide" symmetrical topological structure. The symmetry of this structure enhances the molecule's ability to arrange itself orderly at the interface, the flexible linking group imparts conformational self-adaptation properties, and the hydrophobic shell formed by the fully acetylated modification exhibits excellent carbon dioxide affinity through specific interactions with CO2 molecules. Experiments show that this derivative demonstrates excellent demixing effects in oilfield crude oil-CO2 systems, with a maximum demixing efficiency of up to 28.54% at 1.5 wt%, demonstrating significant application value in the field of carbon dioxide enhanced oil recovery (CEOR). Attached Figure Description

[0017] Figure 1 The nuclear magnetic resonance hydrogen spectrum analysis of the fully acetylated polysaccharide derivatives prepared in Example 2 of this invention; Figure 2 The nuclear magnetic resonance hydrogen spectrum analysis of the fully acetylated polysaccharide derivatives prepared in Example 3 of this invention; Figure 3 The nuclear magnetic resonance hydrogen spectrum analysis of the fully acetylated polysaccharide derivatives prepared in Example 4 of this invention; Figure 4 The nuclear magnetic resonance hydrogen spectrum analysis of the fully acetylated polysaccharide derivatives prepared in Example 5 of this invention; Figure 5 Fourier transform infrared spectroscopy analysis of the fully acetylated polysaccharide derivatives prepared in Examples 2-5 of this invention; Figure 6 The graph shows the effect of the fully acetylated polysaccharide derivatives prepared in Examples 2-5 of this invention on the minimum miscibility pressure of CO2 in an oil field. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 This embodiment discloses a fully acetylated polysaccharide derivative mixing agent, characterized in that it is formed by linking an alkyl polysaccharide glycoside to a glycidyl ether and then fully acetylifying it, with the following general structural formula:

[0020] Where m takes the value of 1-2.5; n takes the value of 2-6; R1 is selected from any one of the straight-chain or branched alkyl groups with 8-14 carbon atoms.

[0021] Example 2 This embodiment provides a method for preparing a fully acetylated polysaccharide derivative, comprising the following steps: S1. Place 32.00g of APG0810 and 0.64g of inorganic strong base catalyst in a three-necked flask and stir for 1 hour in an oil bath at 25°C. Then, heat the system to 60°C and mix 17.40g of ethylene glycol diglycidyl ether and 5.00g of isopropanol in a dropping funnel beforehand. Add the mixture slowly dropwise to the reaction system while stirring to carry out the etherification reaction. Track the reaction with infrared spectroscopy until the reaction is complete. After the reaction is complete, distill off the isopropanol under reduced pressure to obtain APG0810-EGDE.

[0022] S2. 25.00 g of APG0810-EGDE and 28.22 g of acetic anhydride were placed in a four-necked flask. Then, 0.50 g of a weak organic base was added as a catalyst, along with 5.00 g of a dehydrating agent and 0.12 g of an acyl transfer accelerator. Under a nitrogen atmosphere, the reaction system was first stirred at 0°C for 1 hour, then the temperature was increased to 60°C to continue the esterification reaction. The esterification rate was monitored periodically until it remained constant, at which point the reaction was stopped to obtain a fully acetylated polysaccharide derivative. The 1H NMR spectrum analysis of this fully acetylated polysaccharide derivative is as follows: Figure 1 As shown.

[0023] Example 3 This embodiment provides a method for preparing a fully acetylated polysaccharide derivative, comprising the following steps: S1. Place 35.80g of APG1214 and 0.72g of inorganic strong base catalyst in a three-necked flask and stir for 1 hour in an oil bath at 25°C. Then, heat the system to 60°C and mix 17.40g of ethylene glycol diglycidyl ether and 5.00g of isopropanol in a dropping funnel beforehand. Add the mixture slowly dropwise to the reaction system while stirring to carry out the etherification reaction. Track the reaction with infrared spectroscopy until the reaction is complete. After the reaction is complete, distill off the isopropanol under reduced pressure to obtain APG1214-EGDE.

[0024] S2. 25.00 g of APG1214-EGDE and 25.79 g of acetic anhydride were placed in a four-necked flask. Then, 0.50 g of a weak organic base was added as a catalyst, along with 5.00 g of a dehydrating agent and 0.12 g of an acyl transfer accelerator. Under a nitrogen atmosphere, the reaction system was first stirred at 0°C for 1 hour, then the temperature was increased to 60°C to continue the esterification reaction. The esterification rate was monitored periodically until it remained constant, at which point the reaction was stopped to obtain a fully acetylated polysaccharide derivative. The 1H NMR spectrum analysis of this fully acetylated polysaccharide derivative is as follows: Figure 2 As shown.

[0025] Example 4 This embodiment provides a method for preparing a fully acetylated polysaccharide derivative, comprising the following steps: S1. Place 32.00g of APG0810 and 0.60g of inorganic strong base catalyst in a three-necked flask and stir for 1 hour in an oil bath at 25°C. Then, heat the system to 60°C and mix 21.80g of diethylene glycol diglycidyl ether and 5.00g of isopropanol in a dropping funnel beforehand. Add the mixture slowly dropwise to the reaction system while stirring to carry out the etherification reaction. Track the reaction with infrared spectroscopy until the reaction is completed. After the reaction is completed, distill off the isopropanol under reduced pressure to obtain APG0810-DGDE.

[0026] S2. 25.00 g of APG0810-DGDE and 26.72 g of acetic anhydride were placed in a four-necked flask. Then, 0.50 g of a weak organic base was added as a catalyst, along with 5.00 g of a dehydrating agent and 0.12 g of an acyl transfer accelerator. Under a nitrogen atmosphere, the reaction system was first stirred at 0°C for 1 hour, then the temperature was raised to 60°C to continue the esterification reaction. The esterification rate was monitored periodically until it remained constant, at which point the reaction was stopped to obtain a fully acetylated polysaccharide derivative. The 1H NMR spectrum analysis of this fully acetylated polysaccharide derivative is as follows: Figure 3 As shown.

[0027] Example 5 A method for preparing a fully acetylated polysaccharide derivative includes the following steps: S1. Place 35.80g of APG1214 and 0.72g of inorganic strong base catalyst in a three-necked flask and stir for 1 hour in an oil bath at 25°C. Then, heat the system to 60°C and mix 21.80g of diethylene glycol diglycidyl ether and 5.00g of isopropanol in a dropping funnel beforehand. Add the mixture slowly dropwise to the reaction system while stirring to carry out the etherification reaction. Track the reaction with infrared spectroscopy until the reaction is complete. After the reaction is complete, distill off the isopropanol under reduced pressure to obtain APG1214-DGDE.

[0028] S2. 25.00 g of APG1214-DGDE and 24.57 g of acetic anhydride were placed in a four-necked flask. Then, 0.50 g of a weak organic base was added as a catalyst, along with 5.00 g of a dehydrating agent and 0.12 g of an acyl transfer accelerator. Under a nitrogen atmosphere, the reaction system was first stirred at 0°C for 1 hour, then the temperature was increased to 60°C to continue the esterification reaction. The esterification rate was monitored periodically until it remained constant, at which point the reaction was stopped to obtain a fully acetylated polysaccharide derivative. The 1H NMR spectrum analysis of this fully acetylated polysaccharide derivative is as follows: Figure 4 As shown.

[0029] Fourier transform infrared spectroscopy analysis of the polysaccharide derivatives prepared using the methods in Examples 2-5 is shown in the following results. Figure 5 As shown.

[0030] The performance of the polysaccharide derivatives prepared in Examples 2-5 in reducing minimum miscibility pressure was tested. Crude oil samples from an oilfield in China were used for evaluation. The Visibility Injection (VIT) method was employed. The oil phase was injected into a high-temperature, high-pressure visible cell and heated to 70°C. CO2 bubbles were suspended in the oil phase using a capillary tube. The pressure was gradually increased, and the bubble morphology was recorded and the interfacial tension was calculated. The pressure at which the interfacial tension approached zero and the bubble outline was about to dissipate was taken as the minimum miscibility pressure. The minimum miscibility pressure between pure CO2 and crude oil was first measured to be 21.90 MPa. The minimum miscibility pressure of "CO2 + 1.5 wt% fully acetylated sugar derivatives" was determined using the same method. The minimum miscibility pressures of Examples 2, 3, 4, and 5 were 17.44 MPa, 16.11 MPa, 17.23 MPa, and 15.65 MPa, respectively. Example 5 showed the best demixing effect, with a demixing efficiency of up to 28.54%. The effect of this fully acetylated polysaccharide derivative on the minimum miscibility pressure of CO2 in a certain oil field is as follows: Figure 6 As shown.

[0031] The fully acetylated polysaccharide derivatives provided by this invention achieve structural innovation through precise molecular regulation. This structure uses two alkyl polysaccharides as basic units, covalently linked by flexible linking groups constructed from glycidyl ethers, forming a unique "polysaccharide-linking group-polysaccharide" symmetrical topological architecture. Based on this, full acetylation modification forms a regular hydrophobic protective layer on the molecular periphery, successfully constructing a stable structure with both clearly defined hydrophilic regions and a hydrophobic shell.

[0032] This innovative molecular design offers three key structural advantages: First, the symmetrical topological configuration significantly enhances the molecule's ability to arrange itself in an orderly manner at the interface; second, the flexible linker provides the molecule with appropriate conformational freedom, enabling it to adapt to multiphase interface environments; and finally, the synergistic effect of acetylation modification and alkyl chains achieves a precise balance between hydrophilic and hydrophobic properties. Particularly noteworthy is the specific interaction between the densely packed acetyl groups on the periphery of the structure and supercritical carbon dioxide molecules, which gives it excellent carbon dioxide affinity.

[0033] Experimental verification shows that this polysaccharide derivative exhibits excellent interfacial activity in a crude oil-carbon dioxide system test at an oilfield, with a maximum demixing efficiency of 28.54% achieved by a 1.5 wt% fully acetylated sugar derivative. This unique performance, resulting from structural innovation, demonstrates significant application value in oil and gas development fields such as carbon dioxide enhanced oil recovery.

[0034] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its scope and spirit, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A peracetylated polysaccharide derivative facilitating agent, characterized by comprising: A glycidyl ether is connected to an alkyl polyglycoside and fully acetylated to form a structure general formula: Wherein, m is 1-2.5; n is 2-6; R1 is selected from any one of the linear or branched alkyl group with carbon number of 8-14.

2. A method for producing a total acetylated polysaccharide derivative dispersion aid, characterized by, The application relates to a preparation method of a fully acetylated polysaccharide derivative promoting agent, and particularly relates to the following steps. Step 1: alkyl polyglycoside and inorganic strong base catalyst are placed in a reactor, stirred at 25 DEG C for 1h, then the system is heated to 60 DEG C, and mixed glycidyl ether and isopropyl alcohol are slowly added dropwise into the reaction system under stirring, and etherification is carried out to obtain a polysaccharide derivative; Step 2: acetic anhydride and the polysaccharide derivative obtained in step 1 are placed in a reactor according to a molar ratio of (8.00-10.00):1.00, then an organic weak base catalyst, a water removal agent and an acyl transfer accelerator are added, the reaction system is stirred at 0 DEG C for 1h under nitrogen atmosphere protection, then the system is heated to 60 DEG C to continue esterification, and finally a fully acetylated polysaccharide derivative is obtained.

3. The method of claim 2, wherein the method is characterized by the steps of: The molar ratio of the alkyl polyglycoside to the glycidyl ether in step 1 is (2.00-2.50):1.

00.

4. The method of claim 2, wherein the method is characterized by the steps of: The amount of the inorganic strong base catalyst in step 1 is 2.00%-2.50% of the mass of the alkyl polyglycoside.

5. The method for preparing a fully acetylated polysaccharide derivative blending agent according to claim 2, characterized in that, The amount of the organic weak base catalyst in step 2 is 2.00%-2.50% of the mass of the polysaccharide derivative.

6. The method of claim 2, wherein the method is characterized by the steps of: The inorganic strong base is selected from any one or more of sodium hydroxide, potassium hydroxide, sodium hydride, calcium hydroxide and anhydrous sodium carbonate; and the organic weak base is selected from any one or more of pyridine, triethylamine, diisopropyl ethylamine, 2,6-dimethyl pyridine and N-methyl morpholine.

7. The method for preparing a fully acetylated polysaccharide derivative blending agent according to claim 2, characterized in that, The alkyl polyglycoside is selected from any one or more of alkyl glycosides with carbon number of 8-14.

8. The method of claim 2, wherein the method is characterized by the steps of: The water removal agent is selected from any one or more of silica gel, molecular sieve, activated carbon and anhydrous sodium sulfate; and the acyl transfer accelerator is selected from any one or more of 4-dimethylamino pyridine, 4-pyrrolidinyl pyridine, N-methyl imidazole and triazole ionic liquid.

9. Use of a peracetylated polysaccharide derivative miscibility enhancer to reduce the minimum miscibility pressure of CO2 in offshore oil fields, characterized in that, The fully acetylated polysaccharide derivative promoting agent is prepared by the preparation method according to any one of claims 2-8.

10. Use according to claim 9, characterized in that, The concentration of the fully acetylated polysaccharide derivative promoting agent for demixing is 0.3wt%-1.5wt%.

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