Mechanical interlocking type drag reducer based on topological structure and preparation method and application thereof

Abstract

The invention relates to the technical field of oil product drag reducer preparation, in particular to a mechanical interlocking type drag reducer based on a topological structure and a preparation method and application of the mechanical interlocking type drag reducer. The preparation method comprises the following steps: carrying out addition-condensation reaction on a carbonyl compound and a 4-aminobenzoyl compound to obtain an axial intermediate with a long conjugated skeleton; the preparation method comprises the following steps: carrying out a condensation reaction on a long-chain alkyl modified dibenzo-18-crown-6 derivative and 3, 5-bis (trifluoromethylbenzylamine), then mixing with a shaft component precursor compound obtained by carrying out an esterification reaction on a shaft intermediate with a long conjugated skeleton and phenyl p-nitrochloroformate, and carrying out a coordination-driven self-organization reaction to obtain the long-chain alkyl modified shaft component. The mechanical interlocking type drag reducer based on the topological structure is obtained. A chain segment orientation mechanism of a traditional polymer is replaced by a slippage-dissipation mechanism of a mechanical bond, and the dual technical problems that an existing drag reducer is poor in shear resistance and mechanical interlocking molecules are poor in dispersity in an oil phase are solved.

Description

Technical Field

[0001] This invention relates to the field of oil drag reducer preparation technology, specifically to a mechanically interlocking drag reducer based on topological structure, its preparation method, and its application. Background Technology

[0002] With the continued growth of global energy demand, long-distance pipeline transportation of oil and natural gas has become a crucial link in ensuring energy supply. However, the frictional resistance caused by turbulence when fluids flow in pipelines leads to significant energy losses. Statistics show that energy losses due to fluid resistance during pipeline transportation account for more than 30% of the total pumping power, which not only increases operating costs but also exacerbates carbon emissions. Therefore, oil drag reducers, as efficient and economical flow improvers, significantly enhance transportation efficiency by suppressing turbulence and reducing flow resistance, and are widely used in the petrochemical industry.

[0003] Traditional drag-reducing agents primarily rely on the "elastic stretching-relaxation" mechanism of linear polymers (such as polyalphaolefins) to reduce vortex energy dissipation through the orientation of molecular chains in turbulent flow. However, these materials suffer from poor shear resistance in applications: during pipeline transportation, the high shear forces generated when fluid passes through pumps, valves, elbows, and other areas rapidly disrupt the molecular chain structure of the linear polymer, leading to a sharp decline in drag-reduction efficiency. Experiments show that the drag reduction rate of traditional polymer drag-reducing agents decreases by more than 50% after experiencing mechanical shear.

[0004] In recent years, mechanically interlocked molecules (MIMs) have attracted much attention in the field of materials science due to their unique topological characteristics. These molecules (such as rotaxanes and sesquicarbons) achieve physical entanglement between components through mechanical bonds rather than covalent bonds, endowing the materials with excellent energy dissipation capabilities and self-healing properties. For example, the cyclic components in rotaxane molecules can absorb external mechanical energy during axial component sliding, thereby dispersing stress and preventing molecular chain breakage. However, the preparation of traditional MIMs largely relies on template-guided self-assembly techniques, which are cumbersome (5-8 steps) and difficult to meet the needs of industrial production. Furthermore, most MIMs are designed based on polar solvent systems, exhibiting poor dispersibility in non-polar oil phases, and lack molecular structure optimization for drag reduction functions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a mechanically interlocked drag-reducing agent based on topological structure, its preparation method, and its application. First, using dibenzo-18-crown-6 as a template skeleton, a long-chain alkyl side chain is introduced through a fatty alcohol etherification reaction (the long chain improves dispersibility in the non-polar oil phase), yielding a long-chain alkyl-modified dibenzo-18-crown-6 derivative with optimized oil phase dispersibility. Subsequently, a carbonyl-amine nucleophilic addition-condensation of a carbonyl compound with a 4-aminobenzoyl compound yields an shaft intermediate with a long conjugated skeleton. Under alkaline conditions, the shaft intermediate with the long conjugated skeleton is esterified with phenyl p-nitrochloroformate to obtain a shaft component precursor compound. Finally, a low-temperature coordination-driven self-organizing reaction (dynamic assembly of the long-chain alkyl-modified dibenzo-18-crown-6 derivative, the shaft component precursor compound, and 3,5-bis(trifluoromethyl)benzylamine) yields a mechanically interlocked drag-reducing agent based on topological structure. The mechanically interlocked drag reducer based on topology of the present invention has a rotaxane topology. Through the slip-dissipation mechanism of mechanical bonds, it replaces the drag reduction mechanism of traditional polymers that depend on chain segment orientation, thus overcoming the dual technical problems of poor shear resistance and poor dispersibility of mechanically interlocked molecules in the oil phase in existing drag reducers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a method for preparing a mechanically interlocked drag-reducing agent based on topology, comprising the following steps: S1. Using dibenzo-18-crown-6 and fatty alcohol as raw materials, fatty alcohol and dibenzo-18-crown-6 are subjected to etherification reaction in the presence of a catalyst, followed by crystallization and recrystallization to obtain long-chain alkyl-modified dibenzo-18-crown-6 derivatives.

[0007] S2. The carbonyl compound and the 4-aminobenzoyl compound are co-dissolved in a polar organic solvent. In the presence of a zinc / titanium tetrachloride catalyst, the carbonyl group of the carbonyl compound undergoes a nucleophilic addition-condensation reaction with the amino group of the 4-aminobenzoyl compound to obtain an axial intermediate with a long conjugated skeleton. The amino group of the 4-aminobenzoyl compound provides the nucleophilic center, while the carbonyl group of the carbonyl compound provides the carbonyl functional group for the formation of a product containing an imine structure.

[0008] S3. The shaft intermediate with a long conjugated skeleton is mixed with phenyl p-nitrochloroformate and subjected to esterification under alkaline conditions to obtain the shaft component precursor compound. Phenyl p-nitrochloroformate acts as the esterification reagent in the esterification reaction. Its carbonyl carbon exhibits high reactivity and can be nucleophilically attacked by nitrogen atoms, undergoing a nucleophilic substitution reaction to form the ester-based shaft component precursor compound. The unique structure of phenyl p-nitrochloroformate endows it with reactivity and selectivity. Pyridine acts as a base to provide alkaline conditions, neutralizing the generated HCl and preventing excessive acidity from inhibiting the reaction. Simultaneously, it acts as a nucleophilic catalyst to activate acyl chlorides, accelerating ester bond formation; it also improves reaction selectivity and reduces byproducts.

[0009] S4. Long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine are dissolved together in a nonpolar organic solvent and subjected to a condensation reaction. Then, a shaft component precursor compound is added to carry out a coordination-driven self-organizing reaction to form a rotaxane polymer, thereby obtaining a mechanically interlocking drag-reducing agent based on topology. In the coordination-driven self-organizing reaction, the host long-chain alkyl-modified dibenzo-18-crown-6 derivative (containing a macrocyclic structure) has an oxygen atom in its ring containing a lone pair of electrons, which can act as an electron donor (Lewis base); the guest axis component precursor compound contains cation sites (such as ammonium ions and pyridine ions) in its molecule, which act as an electron acceptor (Lewis acid); the oxygen atom (dipole negative end) in the host macrocyclic structure coordinates with the cation site (positive charge center) of the guest through ion-dipole interaction to form a stable host-guest inclusion compound; the long-chain skeleton of the axis component precursor compound passes through the cavity of the macrocyclic structure of the host long-chain alkyl-modified dibenzo-18-crown-6 derivative, and multiple host long-chain alkyl-modified dibenzo-18-crown-6 derivatives are arranged regularly along the axis component through the above coordination, spontaneously forming a "circumaxial" rotaxane structure, which is finally polymerized into a rotaxane polymer.

[0010] Preferably, the mass ratio of dibenzo-18-crown-6 to fatty alcohol is 1:4~9.

[0011] Preferably, in the preparation of long-chain alkyl-modified dibenzo-18-crown-6 derivatives, the etherification reaction conditions are: reaction at 50℃~70℃ for 5h~10h.

[0012] Preferably, the molar ratio of the carbonyl compound, the 4-aminobenzoyl compound, the pyridine, and the p-nitrochlorophenyl ester is 1~1.5:1~1.5:1~1.3:1.1~1.5.

[0013] Preferably, the 4-aminobenzoyl compound is selected from 4-aminobenzophenone or p-aminoacetophenone.

[0014] Preferably, the carbonyl compound is selected from aldehydes or ketones, more preferably benzophenone or benzaldehyde.

[0015] Preferably, the molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative, and 3,5-bis(trifluoromethyl)benzylamine is 1:1~5:1~5.

[0016] Preferably, the esterification reaction conditions are: reaction at -10℃ to 0℃ for 5h to 10h in an anhydrous and oxygen-free CH2Cl2 environment.

[0017] Preferably, the nucleophilic addition-condensation reaction is carried out at 40℃~80℃ for 8h~12h.

[0018] Preferably, the condensation reaction conditions are: reaction at -30℃ to -5℃ for 6h to 15h.

[0019] Preferably, the conditions for coordination-driven self-organizing reaction are: reaction at -30℃ to -5℃ for 6h to 15h.

[0020] Preferably, the zinc / titanium tetrachloride catalyst is composed of zinc and titanium tetrachloride, and the mass ratio of zinc to titanium tetrachloride is 0.5~1:1.

[0021] Preferably, the fatty alcohol is selected from 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol or 1-decanol.

[0022] Preferably, in the preparation of long-chain alkyl-modified dibenzo-18-crown-6 derivatives, the catalyst is selected from polyphosphoric acid or p-toluenesulfonic acid, and the catalyst provides protons to promote the etherification reaction.

[0023] Preferably, the nonpolar organic solvent is selected from n-heptane, toluene, dichloromethane, or acetone.

[0024] Preferably, the polar organic solvent is selected from tetrahydrofuran, N,N-dimethylformamide or dimethyl sulfoxide.

[0025] A second objective of this invention is to provide a mechanically interlocking drag reducer based on topological structure prepared by the above-described method.

[0026] The third objective of this invention is to provide the application of the above-mentioned mechanically interlocked drag-reducing agent based on topology in the preparation of fuel drag-reducing agents, wherein the application method is as follows: The mechanically interlocked drag reducer based on topology is cryogenically treated and then dissolved in fuel; wherein the mass ratio of the mechanically interlocked drag reducer based on topology to fuel is 1:40000~50000.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing a mechanically interlocked drag-reducing agent based on topological structure. Using dibenzo-18-crown-6 and a fatty alcohol as raw materials, the fatty alcohol undergoes an etherification reaction with dibenzo-18-crown-6 in the presence of a catalyst, followed by crystallization and recrystallization to obtain a long-chain alkyl-modified dibenzo-18-crown-6 derivative. A carbonyl compound and a 4-aminobenzoyl compound are co-dissolved in a polar organic solvent. In the presence of a zinc / titanium tetrachloride catalyst, the carbonyl group of the carbonyl compound undergoes a nucleophilic addition reaction with the amino group of the 4-aminobenzoyl compound. A condensation reaction yields an shaft intermediate with a long conjugated backbone. Under alkaline conditions, the hydroxyl groups of the shaft intermediate with the long conjugated backbone undergo esterification with the chloroformyl groups of phenyl p-nitrochloroformate to form ester bonds, yielding a shaft component precursor compound. A long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine are dissolved together in a nonpolar organic solvent and undergo a condensation reaction to form imine bonds. These imine bonds are then mixed with the shaft component precursor compound and undergo a coordination-driven self-organizing reaction to form a rotaxane polymer, resulting in a mechanically interlocked drag-reducing agent based on topological structure. This invention utilizes in-situ polymerization technology to simultaneously construct the polymer backbone and mechanically interlocked structure, avoiding the complexity of traditional multi-step synthesis and reducing production costs. Furthermore, by introducing rotaxane or quasi-rotaxane structures as polymer side chains, the "molecular pulley" effect of mechanical interlocking disperses shear stress, significantly improving the fracture resistance of the topologically interlocked drag-reducing agent.

[0028] Furthermore, the mechanically interlocked drag reducer based on topological structure of the present invention has a rotaxane topological structure. Through the slip-dissipation mechanism of mechanical bonds, it replaces the drag reduction mechanism of traditional polymers that relies on chain segment orientation, overcoming the dual technical challenges of poor shear resistance and poor dispersibility of mechanically interlocked molecules in the oil phase. Specifically, it consists of a "shaft assembly" (long-chain molecule) and a "wheel assembly" (macrocyclic molecule, such as dibenzo-18-crown-6 derivative). The macrocyclic molecule (wheel) is nested on the long-chain molecule (shaft), and the two ends of the shaft typically have "blocking groups" (such as nitrobenzene groups formed in the previous reaction)—the size of the blocking group is larger than the cavity size of the macrocycle, preventing the macrocycle from sliding off the shaft. This spatial entanglement relationship of "ring nested on shaft, locked at both ends" is the mechanical bond. By replacing the chain segment orientation mechanism of traditional polymers with the slip-dissipation mechanism of mechanical bonds, the dual technical challenges of poor shear resistance and poor dispersibility of mechanically interlocked molecules in the oil phase are overcome.

[0029] 2. The topologically based mechanically interlocked drag reducer rotaxane of this invention consists of a linear "axis" molecule passing through a cyclic "wheel" molecule, forming a mechanically interlocked structure. This structure allows for relatively restricted yet flexible movement among the components of the topologically based mechanically interlocked drag reducer molecule when subjected to shear forces. The sliding and rotational movement of the cyclic molecule around the axis molecule can buffer and disperse shear forces, preventing stress concentration at a single point and thus avoiding chain breakage of the topologically based mechanically interlocked drag reducer molecule. Like a sophisticated mechanical device, the various components cooperate and constrain each other, maintaining relative stability of the overall structure through dynamic adjustments under external forces.

[0030] 3. The mechanically interlocked drag reducer based on topology provided by this invention, when dissolved in diesel fuel, exhibits a significant drag reduction effect and excellent shear resistance. Compared to polyolefin mechanically interlocked drag reducers prepared by existing technologies, the mechanically interlocked drag reducer based on topology of this invention has superior shear resistance; after one shearing event, its drag reduction rate retention is approximately 2.36 times that of the polyolefin drag reducer. Attached Figure Description

[0031] Figure 1 The image shows the infrared spectrum of the mechanically interlocked drag-reducing agent based on topology structure in Embodiment 1 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased commercially or prepared by existing methods. The polyolefin drag-reducing agent was purchased from Tianjin Dekun Energy Technology Co., Ltd.

[0034] In existing technologies, traditional drag-reducing agents mainly rely on the chain segment orientation mechanism of linear polymers, which has the inherent defect of poor shear resistance. Their molecular chains are easily damaged by high shear forces, resulting in a significant decrease in drag-reducing efficiency. While mechanically interlocked molecules (MIMs) with energy dissipation advantages can disperse stress through mechanical bond slip, they are limited by the cumbersome template synthesis steps and low yield (usually less than 30%). Furthermore, the lack of hydrophobic groups such as long-chain alkyl groups in their molecular structure leads to poor compatibility with non-polar oils. These two major bottlenecks severely restrict the practical application of mechanically interlocked structures in the field of drag-reducing agents.

[0035] To address the problems existing in the prior art, this invention provides a method for preparing a mechanically interlocked drag-reducing agent based on topological structure, comprising the following steps: using dibenzo-18-crown-6 and a fatty alcohol as raw materials, the fatty alcohol and dibenzo-18-crown-6 undergo an etherification reaction in the presence of a catalyst, followed by crystallization and recrystallization to obtain a long-chain alkyl-modified dibenzo-18-crown-6 derivative; dissolving a carbonyl compound and a 4-aminobenzoyl compound together in a polar organic solvent, and in the presence of a zinc / titanium tetrachloride catalyst, the carbonyl group of the carbonyl compound undergoes a nucleophilic addition-condensation reaction with the amino group of the 4-aminobenzoyl compound to obtain an axial intermediate with a long conjugated backbone; using a carbonyl compound and a 4-aminobenzoyl compound as raw materials, the method further comprises the following steps: ... Using a shaft intermediate with a long conjugated backbone and phenyl p-nitrochloroformate as raw materials, under alkaline conditions, the hydroxyl groups of the shaft intermediate with the long conjugated backbone undergo an esterification reaction with the chloroformyl groups of phenyl p-nitrochloroformate to form ester bonds, yielding a shaft component precursor compound. Using a long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine as raw materials, in the presence of a nonpolar organic solvent, the aldehyde groups of the long-chain alkyl-modified dibenzo-18-crown-6 derivative undergo a condensation reaction with the amino groups of 3,5-bis(trifluoromethyl)benzylamine to form imine bonds, which are then mixed with the shaft component precursor compound to undergo a coordination-driven self-organizing reaction, forming a rotaxane polymer, thus obtaining a mechanically interlocked drag-reducing agent based on topological structure.

[0036] To address the problem of poor shear resistance in traditional drag-reducing agents in existing technologies, this invention introduces a rotaxane mechanical interlocking structure and utilizes the dynamic coordination assembly of long-chain alkyl-modified cyclic crown ether derivatives and shaft component precursors to construct a supramolecular network with a "molecular pulley" effect. Under shear force, the relative sliding of the ring-shaft components disperses stress concentration, overcoming the technical defect of linear polymer chains being prone to breakage and causing drag reduction efficiency to decrease.

[0037] To address the problem of cumbersome mechanical interlocking molecular synthesis steps in existing technologies, this invention adopts a modular synthesis strategy. It uses fatty alcohol etherification to modify crown ether rings to improve oil compatibility, designs fluorinated aromatic axis component precursors to enhance coordination ability, and combines low-temperature coordination-driven self-organizing reactions to reduce the traditional 5 to 8 steps of MIM synthesis to 3 key reactions, thus overcoming the technical bottlenecks of complex processes and low yields.

[0038] To address the problem of poor oil phase dispersibility in existing mechanically interlocked structures, this invention utilizes dibenzo-18-crown-6 and long-chain fatty alcohols (C6- ... 10 The etherification reaction introduces 4 to 9 alkyl side chains around the crown ether ring to form a hydrophobic protective layer, which increases the solubility of the mechanically interlocked structure in non-polar diesel systems to more than 2.5 mg / mL, overcoming the phase separation problem caused by the exposure of polar groups in traditional MIMs.

[0039] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments: Example 1 A method for preparing a mechanically interlocked drag-reducing agent based on topology includes the following steps: S1. First, add 55.7 g of polyphosphoric acid to a round-bottom flask and heat to 60°C. Continue adding 20 g of dibenzo-18-crown-6 to the flask until completely dissolved. Then add 80 g of 1-hexanol, resulting in a mass ratio of dibenzo-18-crown-6 to 1-hexanol of 1:4. React at 60°C for 10 hours until the solution turns brown. Next, slowly add an appropriate amount of water to the system to induce layering. Extract the layers using CH2Cl2 and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain a white powdery crystal, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0040] S2. Add 0.92 g of benzophenone and 0.986 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 40 °C for 12 h to obtain an axial intermediate with a long conjugated skeleton.

[0041] S3. Add 0.593g of pyridine and 1.293g of phenyl p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at 0℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0042] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -15°C for 6 h. Then, the shaft component precursor compound was added and the reaction was continued for 10 h to obtain a mechanically interlocking drag-reducing agent based on topological structure. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:1.1:1.1.

[0043] Example 2 A method for preparing a mechanically interlocking drag-reducing agent based on topological structure is the same as the preparation steps in Example 1, except that the molar ratio of benzophenone, 4-aminobenzophenone, and phenyl p-nitrochloroformate is replaced from 1:1:1.2 to 1:1:1.1, and includes the following steps: S1. First, add 55.7 g of polyphosphoric acid to a round-bottom flask and heat to 60°C. Continue adding 20 g of dibenzo-18-crown-6 to the flask until completely dissolved. Then add 80 g of 1-hexanol, resulting in a mass ratio of dibenzo-18-crown-6 to 1-hexanol of 1:4. React at 60°C for 10 hours until the solution turns brown. Next, slowly add an appropriate amount of water to the system to induce layering. Extract the layers using CH2Cl2 and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain a white powdery crystal, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0044] S2. Add 0.92 g of benzophenone and 0.986 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 80 °C for 8 h to obtain an axial intermediate with a long conjugated skeleton.

[0045] S3. Add 0.593g of pyridine and 1.185g of phenyl p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at 0℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0046] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -15°C for 6 h. Then, the shaft component precursor compound was added and the reaction was continued for 10 h to obtain a mechanically interlocking drag-reducing agent based on topological structure. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:1.1:1.1.

[0047] Example 3 A method for preparing a mechanically interlocking drag-reducing agent based on topological structure is the same as the preparation steps in Example 1, except that the molar ratio of benzophenone, 4-aminobenzophenone, and phenyl p-nitrochloroformate is replaced from 1:1:1.2 to 1:1:1.5, and includes the following steps: S1. First, add 55.7 g of polyphosphoric acid to a round-bottom flask and heat to 60°C. Then, add 20 g of dibenzo-18-crown-6 to the round-bottom flask and, after it is completely dissolved, add 80 g of 1-hexanol, i.e., the mass ratio of dibenzo-18-crown-6 to 1-hexanol is 1:4. React at 60°C for 10 hours until the solution turns brown. Next, slowly add an appropriate amount of water to the system to induce phase separation. Extract the system using CH2Cl2 and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain a white powdery crystal, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0048] S2. Add 0.92 g of benzophenone and 0.986 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 40 °C for 12 h to obtain an axial intermediate with a long conjugated skeleton.

[0049] S3. Add 0.593g of pyridine and 1.616g of phenyl p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at 0℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0050] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -15°C for 6 h. Then, the shaft component precursor compound was added and the reaction was continued for 10 h to obtain a mechanically interlocking drag-reducing agent based on topological structure. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:1.1:1.1.

[0051] Example 4 A method for preparing a mechanically interlocking drag-reducing agent based on topological structure is the same as the preparation steps in Example 1, except that the molar ratio of benzophenone, 4-aminobenzophenone, and phenyl p-nitrochloroformate is replaced from 1:1:1.2 to 1.5:1.5:1.2, and includes the following steps: S1. First, add 55.7g of polyphosphoric acid to a round-bottom flask and heat to 60℃. Add 20g of dibenzo-18-crown-6 to the round-bottom flask and, after it is completely dissolved, add 80g of 1-hexanol, i.e., the mass ratio of dibenzo-18-crown-6 to 1-hexanol is 1:4. React at 60℃ for 10h until the solution turns brown. Then, slowly add an appropriate amount of water to the system to promote the separation of the system into layers. Use CH2Cl2 for extraction and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain white powdery crystals, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0052] S2. Add 1.38 g of benzophenone and 1.497 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 40 °C for 12 h to obtain an axial intermediate with a long conjugated skeleton.

[0053] S3. Add 0.593g of pyridine and 1.293g of phenyl p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at 0℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0054] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -15°C for 6 h. Then, the shaft component precursor compound was added and the reaction was continued for 10 h to obtain a mechanically interlocking drag-reducing agent based on topological structure. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:1.1:1.1.

[0055] Example 5 A method for preparing a mechanically interlocking drag-reducing agent based on topological structure is the same as the preparation steps in Example 1, except that the molar ratio of the S4 central shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative, and 3,5-bis(trifluoromethyl)benzylamine is replaced from 1:1.1:1.1 to 1:5:5. The method includes the following steps: S1. First, add 55.7 g of polyphosphoric acid to a round-bottom flask and heat to 60°C. Next, add 20 g of dibenzo-18-crown-6 to the flask and, after complete dissolution, add 80 g of 1-hexanol, resulting in a mass ratio of dibenzo-18-crown-6 to 1-hexanol of 1:4. React at 50°C for 10 hours until the solution turns brown. Then, slowly add an appropriate amount of water to the system to induce layering. Extract the layer using CH2Cl2 and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain a white powdery crystal, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0056] S2. Add 0.92 g of benzophenone and 0.986 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 40 °C for 12 h to obtain an axial intermediate with a long conjugated skeleton.

[0057] S3. Add 0.593g of pyridine and 1.293g of phenyl p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at 0℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0058] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -30°C for 15 h. Then, the shaft component precursor compound was added and the reaction was continued for 15 h to obtain a mechanically interlocked drag-reducing agent based on topology. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:5:5.

[0059] Example 6 A method for preparing a mechanically interlocking drag-reducing agent based on topological structure is the same as the preparation steps in Example 1, except that the molar ratio of the S3 central shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative, and 3,5-bis(trifluoromethyl)benzylamine is replaced from 1:1.1:1.1 to 1:5:5. The method includes the following steps: S1. First, add 55.7 g of polyphosphoric acid to a round-bottom flask and heat to 60°C. Then, add 20 g of dibenzo-18-crown-6 to the flask until completely dissolved. Next, add 180 g of 1-hexanol, resulting in a dibenzo-18-crown-6 to 1-hexanol mass ratio of 1:9. React at 70°C for 5 hours until the solution turns brown. Then, slowly add an appropriate amount of water to the system to induce stratification. Extract the mixture using CH2Cl2 and collect the upper milky white liquid. Subsequently, the milky white liquid was washed with a 20% NaOH solution until alkaline, and then washed with water until neutral, yielding a golden-yellow opaque liquid. The golden-yellow opaque liquid was concentrated under reduced pressure to obtain a pale yellow viscous liquid. Finally, the viscous liquid was heated and dissolved in n-heptane, and then cooled and crystallized in a refrigerator to obtain a pale yellow powder. After filtering the pale yellow powder, it was recrystallized again in n-heptane, filtered, and dried to obtain a white powdery crystal, namely the long-chain alkyl-modified dibenzo-18-crown-6 derivative.

[0060] S2. Add 0.92 g of benzophenone and 0.986 g of 4-aminobenzophenone to 20 mL of tetrahydrofuran, and add 0.067 g of zinc / titanium tetrachloride catalyst. React at 40 °C for 12 h to obtain an axial intermediate with a long conjugated skeleton.

[0061] S3. Add 0.593g of pyridine and 1.293g of p-nitrochloroformate to the shaft intermediate with a long conjugated skeleton, and react at -10℃ for 10h under anhydrous and oxygen-free CH2Cl2 conditions to obtain the shaft assembly precursor compound.

[0062] S4. Using toluene as a solvent, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine were reacted at -5°C for 6 h. Then, the shaft component precursor compound was added and the reaction was continued for 6 h to obtain a mechanically interlocked drag-reducing agent based on topology. The molar ratio of the shaft component precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative and 3,5-bis(trifluoromethyl)benzylamine was controlled to be 1:1:1.

[0063] Comparative Example 1 A method for preparing a polyolefin drag-reducing agent includes the following steps: S1. α-Octene and α-Dodecene are treated separately by molecular sieve packing adsorption columns and stored under air-isolated conditions for later use.

[0064] S2. Place the fully dried polymerization reactor in a circulating cold bath and control the temperature at -5℃. Under the protection of nitrogen atmosphere, add 20g of α-octene and 100g of α-dodecene to the polymerization reactor in sequence and mix. After mixing evenly, add 0.01g of triethylaluminum. Increase the stirring speed to mix evenly. Then add 0.03g of titanium tetrachloride to the polymerization reactor and react at a cold bath temperature of -10℃ for 72h to obtain a polyolefin drag reducer.

[0065] observe Figure 1 Therefore, 3000cm -1 ~3100cm -1 For the stretching vibration of aromatic ring CH (dibenzo-18-crown-6, shaft assembly aromatic ring, 2850cm) -1 ~2960cm -1 For long-chain alkyl CH stretching vibration, 1730 cm⁻¹ -1 ~1750cm -1 The shaft assembly exhibits C=O stretching vibration due to ester bond, 1100cm. -1 ~1200cm -1 This is the CF stretching vibration of the CF3 group, 700 cm⁻¹ -1 ~900cm -1 The out-of-plane bending vibration of the aromatic ring CH was used to verify the successful preparation of the mechanically interlocked drag-reducing agent based on the topological structure.

[0066] Examples 1 to 6 of this invention all yielded mechanically interlocked drag reducers based on topological structures, and the effects were parallel. The mechanically interlocked drag reducer based on topological structures obtained in Example 1 is used as an example to be applied to diesel fuel materials and studied: A mechanically interlocking drag-reducing agent based on a topology structure was dissolved in diesel fuel at a mass ratio of 1:40000. The solution was heated at 60°C for 20 hours until completely dissolved, yielding a mechanically interlocking drag-reducing agent solution based on a topology structure. Both the 20 ppm polyolefin drag-reducing agent and the mechanically interlocking drag-reducing agent solution based on a topology structure were tested using a diesel fuel drag reduction evaluation testing system. The testing method was as follows:

[0067] Testing method: Measurements were performed using an indoor loop drag reduction testing device in accordance with industry standard SY / T6578-2016, "Technical Specification for Adding Drag Reducing Agents to Oil Pipelines". Under the same conditions, the frictional pressure drop of the indoor loop test section was measured before and after adding the drag reducing agent to the liquid. The drag reduction rate was calculated according to formula (1), and the drag reduction effect of the drag reducing agent was evaluated based on the drag reduction rate. The test results are shown in Table 1.

[0068] .

[0069] Where ∆P0 represents the frictional pressure drop of the indoor loop test section before the addition of the drag-reducing agent, ∆P DRA This indicates the frictional pressure drop of the indoor loop test section after the addition of a drag-reducing agent.

[0070] Table 1. Comparison of drag reduction shear properties between the mechanically interlocked drag-reducing agent based on topology structure in Examples 1-6 and the polyolefin drag-reducing agent in Comparative Example 1. According to the results in Table 1, the mechanically interlocked polymer drag reducer prepared in this invention has a better drag reduction effect than the polyolefin drag reducer of Comparative Example 1. Furthermore, the mechanically interlocked polymer drag reducer of this invention has good shear resistance, and its performance after one shearing is also significantly better than that of the polyolefin drag reducer of Comparative Example 1.

[0071] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for preparing a mechanically interlocked drag-reducing agent based on topological structure, characterized in that, Includes the following steps: Using dibenzo-18-crown-6 and fatty alcohol as raw materials, fatty alcohol and dibenzo-18-crown-6 are subjected to etherification reaction in the presence of a catalyst, followed by crystallization and recrystallization to obtain long-chain alkyl-modified dibenzo-18-crown-6 derivatives. A carbonyl compound and a 4-aminobenzoyl compound were co-dissolved in a polar organic solvent. In the presence of a zinc / titanium tetrachloride catalyst, the carbonyl group of the carbonyl compound and the amino group of the 4-aminobenzoyl compound underwent a nucleophilic addition-condensation reaction to obtain an axial intermediate with a long conjugated skeleton. Using an axial intermediate with a long conjugated skeleton and phenyl p-nitrochloroformate as raw materials, under alkaline conditions, the hydroxyl groups of the axial intermediate with a long conjugated skeleton react with the chloroformyl groups of phenyl p-nitrochloroformate to form ester bonds, thus obtaining the axial component precursor compound. Using long-chain alkyl-modified dibenzo-18-crown-6 derivatives and 3,5-bis(trifluoromethyl)benzylamine as raw materials, in the presence of a nonpolar organic solvent, the aldehyde group of the long-chain alkyl-modified dibenzo-18-crown-6 derivative undergoes a condensation reaction with the amino group of 3,5-bis(trifluoromethyl)benzylamine to form an imine bond. This imine bond is then mixed with a shaft component precursor compound and undergoes a coordination-driven self-organizing reaction to form a rotaxane polymer, thus obtaining a mechanically interlocking drag-reducing agent based on topological structure.

2. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The molar ratio of carbonyl compound, 4-aminobenzoyl compound and p-nitrochlorobenzoate is 1~1.5:1~1.5:1.1~1.

5.

3. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The molar ratio of the shaft assembly precursor compound, the long-chain alkyl-modified dibenzo-18-crown-6 derivative, and 3,5-bis(trifluoromethyl)benzylamine is 1:1~5:1~5.

4. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The conditions for the nucleophilic addition-condensation reaction are: reaction at 40℃~80℃ for 8h~12h.

5. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The esterification reaction conditions are: reaction at -10℃ to 0℃ for 5h to 10h in an anhydrous and oxygen-free CH2Cl2 environment.

6. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The condensation reaction conditions are: reaction at -30℃ to -5℃ for 6 to 15 hours.

7. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The conditions for coordination-driven self-organizing reaction are: reaction at -30℃ to -5℃ for 6h to 15h.

8. The method for preparing a mechanically interlocked drag-reducing agent based on topology structure according to claim 1, characterized in that, The mass ratio of dibenzo-18-crown-6 to fatty alcohol is 1:4~9.

9. A mechanically interlocking drag reducer based on topology, prepared by the method according to any one of claims 1 to 8.

10. The application of the mechanically interlocked drag-reducing agent based on topology as described in claim 9 in the preparation of fuel drag-reducing agents, characterized in that, The application method is as follows: The mechanically interlocking drag reducer based on topology is cryogenically treated and then dissolved in fuel. Among them, the mass ratio of mechanically interlocked drag reducer based on topology structure to fuel is 1:40000~50000.

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