Application of block copolymer in hydrocarbon fuel purification dispersant

Abstract

The invention discloses an application of a block copolymer in a hydrocarbon fuel purification dispersant, the block copolymer is polyalkyl methacrylate-acrylamide, and the block copolymer is a hyperbranched block copolymer or a linear block copolymer. Amino polar groups in the block copolymer provided by the invention can adsorb soluble oxidized macromolecular active substances, and non-polar tails can penetrate into fuel molecules to form a space barrier to prevent particle aggregation and provide oil solubility, so that the fuel molecules are uniformly dispersed in a system; the block copolymer can be rapidly prepared by utilizing photo-initiated polymerization; the molecular structure of the hyperbranched copolymer has more excellent thermal stability, and the hyperbranched copolymer can be used as a potential candidate of a hydrocarbon fuel purification dispersant in an aircraft.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrocarbon fuel detergent dispersants, and particularly relates to an application of a block copolymer in a hydrocarbon fuel detergent dispersant. BACKGROUND

[0002] A large amount of heat is generated due to friction when an aircraft is flying at high speed, resulting in excessively high temperatures of components such as lubrication systems, hydraulic systems and combustion chambers. The endothermic hydrocarbon fuel not only serves as a propellant, but also as a coolant to provide effective thermal protection. However, under high temperature (150 °C) and high pressure (1.5 MPa), the molecules in the hydrocarbon fuel will undergo chain reactions with dissolved oxygen to form soluble macromolecular oxidative active substances. These soluble macromolecular oxidative active substances further undergo dehydrogenation condensation reactions at high temperatures to form colloidal and solid deposits. During the long-term operation of the aircraft, surface deposits gradually accumulate and adhere to the inner wall of the engine pipeline, eventually forming coke. This can seriously affect the cooling efficiency of the fuel in the passage, possibly leading to fuel delivery system blockage and injection system failure, and even ultimately causing a safety accident. Therefore, the study of long-term thermal oxidative deposition inhibition of hydrocarbon fuel has important significance.

[0003] The main methods for reducing the oxidation deposition of hydrocarbon fuel include fuel refining, fuel deoxygenation, fuel system optimization and the use of additives. Among them, the use of additives, so-called detergent dispersants, can significantly reduce the formation of soluble macromolecular oxidative active substances and deposits, and is widely concerned in the industry due to its low cost, high inhibition and adsorption efficiency, simple synthesis and easy operation. So far, polyisobutylene succinimide (PIBSI) as a commercial dispersant, such as Chinese patent CN 116003657 B discloses a preparation method of a single polyisobutylene succinimide, has been widely used in the study of hydrocarbon fuel thermal oxidative deposition inhibition. However, due to the limited molecular weight of polyisobutylene succinimide (PIBSI) and the small number of polar groups in the molecule, the strength and number of active sites are limited, which greatly limits its effective adsorption of macromolecular oxidative active substances and deposits, and its dispersion efficiency is poor even at a higher concentration level. In addition, there are limited reports on hydrocarbon fuel detergent dispersants, such as Chinese patent CN101665732B (which discloses a gasoline detergent dispersant containing 60-80 parts by weight of benzoyl polyisobutylene dimethyl amino pyridine with high surface activity and 13-35 parts by weight of N, N-bis-hydroxyethyl alkyl amide) and Chinese patent CN103320183B (which discloses a bio-based methanol gasoline detergent dispersant composed of 30-40% of a surface active component, 32-35% of a dispersing peat component and 30-35% of a detergent washing component) disclose gasoline detergent dispersants, which are quite different from the application conditions of hydrocarbon fuels.

[0004] Therefore, it is currently a technical problem to be solved to simply synthesize a block copolymer with high dispersion and high adsorption efficiency. SUMMARY

[0005] The application aims to provide an application of a block copolymer in a hydrocarbon fuel detergent dispersant, which has the advantages of high efficiency in dispersing soluble macromolecular oxidative active substances in the hydrocarbon fuel, excellent thermal stability, and can be quickly prepared by photoinitiated polymerization.

[0006] To achieve the above-mentioned application purposes, the technical solution provided by the application is as follows: The application of a block copolymer in a hydrocarbon fuel detergent dispersant, wherein the block copolymer is polyalkyl methacrylate-acrylamide, and the block copolymer is a hyperbranched block copolymer or a linear block copolymer.

[0007] The technical principle of the application is that the block copolymer provided by the application is polyalkyl methacrylate-acrylamide, which has both polar and non-polar groups. The amino polar group can adsorb soluble oxidative macromolecular active substances, the non-polar tail can penetrate into the interior of the fuel molecules to form a spatial barrier to prevent particle aggregation, and provide oil solubility, so that it is uniformly dispersed in the system. The performance of the block copolymer can be adjusted by adjusting the molecular structure of the block copolymer or / and the ratio of the polar segment and the non-polar segment, so as to adapt to different application scenarios.

[0008] The molar ratio of alkyl methacrylate to acrylamide in the block copolymer is 2-4:1.

[0009] As a preferred, the block copolymer is a hyperbranched block copolymer polyalkyl methacrylate-acrylamide. The hyperbranched block copolymer has a larger molecular weight and a larger number of active sites, and has a higher adsorption efficiency of soluble oxidative macromolecular active substances. And the molecular structure of the hyperbranched copolymer has more excellent thermal stability, and can be used as a potential candidate for hydrocarbon fuel detergent dispersant in aircraft.

[0010] The preparation method of the block copolymer is that alkyl methacrylate, acrylamide and photoinitiator are mixed in an organic solvent to perform photoinitiated free radical polymerization to obtain a linear block copolymer polyalkyl methacrylate-acrylamide; or alkyl methacrylate, acrylamide, photoinitiator and branching agent are mixed in an organic solvent to perform photoinitiated free radical polymerization to obtain a hyperbranched block copolymer polyalkyl methacrylate-acrylamide.

[0011] The branching agent is pentaerythritol tetraacrylate, and the addition amount of the branching agent is 8-12 % of the total mass of alkyl methacrylate and acrylamide.

[0012] The amount of photoinitiator added is 0.5-1.5% of the total mass of alkyl methacrylate and acrylamide. The ultraviolet-visible light emission wavelength of the photoinitiated free radical polymerization reaction is 320-600 nm, and the ultraviolet-visible light irradiation time is 0.5 hours to 2 hours.

[0013] The organic solvent is toluene or xylene, and the photoinitiator is diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide.

[0014] The alkyl methacrylate has 10 to 18 alkyl groups in its side chain.

[0015] The hydrocarbon fuel is a hook-type tetrahydrodicyclopentadiene (JP-10).

[0016] Compared with the prior art, the beneficial effects of the present invention are reflected in: (1) The hyperbranched block copolymer and linear block copolymer provided by the present invention have strong oil solubility and can be quickly dissolved in JP-10; the dispersion effect of amine groups is significantly stronger than that of hydroxyl and carboxyl groups, and the dispersion efficiency increases with the increase of the proportion of amine blocks. (2) The hyperbranched block copolymers and linear block copolymers provided by the present invention have larger molecular weights and more active sites than commercial dispersants, and have higher adsorption efficiency for soluble oxidizing macromolecular active substances; and the adsorption efficiency of hyperbranched block copolymers is relatively higher. (3) The thermal stability of the hyperbranched block copolymer provided by the present invention is relatively higher than that of the linear block copolymer, and it is preferred to be used as a cleaning and dispersing agent for hydrocarbon fuels. (4) The present invention uses photo-initiated polymerization to synthesize hyperbranched block copolymers (HMC-AM) quickly, efficiently and conveniently, avoiding the limitations of traditional free radical polymerization methods that require vacuum, nitrogen, high temperature and long reaction time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the hyperbranched block copolymer polyalkyl methacrylate-acrylamide in this invention; Figure 2 Schematic diagrams of the linear block copolymers polyalkyl methacrylate-acrylamide, polyalkyl methacrylate-methallyl alcohol, and polyalkyl methacrylate-methacrylic acid; Figure 3 The ultraviolet transmittance of soluble oxidizing macromolecular active substances in the hydrocarbon fuel JP-10 oxidizing liquid of Examples 1-4 and Comparative Example 4 is shown. Figure 4The ultraviolet transmittance of soluble oxidizing macromolecular active substances in the hydrocarbon fuel JP-10 oxidizing liquid in Examples 1, 3, and Comparative Examples 2-4 is shown. Figure 5 Thermogravimetric analysis results of the copolymers obtained in Examples 1-4 and Comparative Examples 2-3 are shown in the figure. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments.

[0019] Example 1: Hyperbranched block copolymer (HMC-AM) 4.66 g of hexadecyl methacrylate, 0.36 g of acrylamide, and 0.53 g of branching agent (pentaerythritol tetraacrylate) were dissolved in 10 mL of toluene. 0.055 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, the hyperbranched block copolymer HMC-AM. The molar ratio of hexadecyl methacrylate to acrylamide was 3:1.

[0020] The structure of the amphiphilic hyperbranched block copolymer HMC-AM is as follows: Figure 1 As shown, it should be noted that since block copolymers are random copolymers, the structures shown are merely examples.

[0021] Hydrocarbon fuel JP-10 was accelerated to oxidation at 150 °C and 1.5 MPa for 70 minutes to obtain a hydrocarbon fuel oxidation liquid containing soluble macromolecular oxidizing active substances. A detergent-dispersant was added to the hydrocarbon fuel oxidation liquid to observe its dispersion performance on the soluble macromolecular oxidizing active substances.

[0022] The effects of adding different detergents and dispersants on the dispersion of soluble macromolecular oxidizing active substances were evaluated using ultraviolet spectrophotometry. Lower ultraviolet transmittance indicated that the soluble macromolecular oxidizing active substances were more uniformly dispersed in the system and had a lower degree of deposition. The morphology and ultraviolet transmittance of the untreated JP-10 oxidation solution were observed every two hours.

[0023] Example 2: Amine-containing linear block copolymer (HMC-AM-b) 4.66 g of hexadecyl methacrylate and 0.53 g of acrylamide were dissolved in 10 mL of toluene. 0.052 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, an amino-containing linear block copolymer, HMC-AM-b. The molar ratio of hexadecyl methacrylate to acrylamide was 2:1.

[0024] Amine-containing linear block copolymers HMC-AM-b, such as Figure 2 As shown.

[0025] As in Example 1, an amino-containing linear block copolymer (HMC-AM-b) was added to JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0026] Example 3: Amine-containing linear block copolymer (HMC-AM-c) 4.66 g of hexadecyl methacrylate and 0.36 g of acrylamide were dissolved in 10 mL of toluene. 0.051 g of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, a photoinitiator, was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, an amino-containing linear block copolymer, HMC-AM-c. The molar ratio of hexadecyl methacrylate to acrylamide was 3:1.

[0027] As in Example 1, an amino-containing linear block copolymer (HMC-AM-c) was added to JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0028] Example 4: Amine-containing linear block copolymer (HMC-AM-d) 3.73 g of hexadecyl methacrylate and 0.21 g of acrylamide were dissolved in 10 mL of toluene. 0.039 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, an amine-containing linear block copolymer, HMC-AM-d. The molar ratio of hexadecyl methacrylate to acrylamide was 4:1.

[0029] As in Example 1, an amino-containing linear block copolymer (HMC-AM-d) was added to JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0030] Comparative Example 1: Amine-containing linear block copolymer (HMC-AM-a) 3.11 g of hexadecyl methacrylate and 0.71 g of acrylamide were dissolved in 10 mL of toluene. 0.038 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, an amino-containing linear block copolymer, HMC-AM-a. The molar ratio of hexadecyl methacrylate to acrylamide was 1:1. Due to the high proportion of polar blocks, the copolymer's oil solubility was deteriorated, therefore it could not be used in hydrocarbon fuels.

[0031] Comparative Example 2: Hydroxyl-containing linear block copolymer (HMC-AO) 4.66 g of hexadecyl methacrylate and 0.37 g of allyl methacrylate were dissolved in 10 mL of toluene. 0.052 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, a hydroxyl-containing linear block copolymer, HMC-AO. The molar ratio of hexadecyl methacrylate to allyl methacrylate was 3:1.

[0032] The structure of the hydroxyl-containing linear block copolymer HMC-AO is as follows: Figure 2 As shown.

[0033] As in Example 1, a hydroxyl-containing linear block copolymer (HMC-AO) was added to JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0034] Comparative Example 3: Carboxyl-containing linear block copolymer (HMC-AC) 4.66 g of hexadecyl methacrylate and 0.43 g of methacrylic acid were dissolved in 10 mL of toluene. 0.051 g of photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the reaction system. The mixture was irradiated with UV-Vis light at a wavelength of 365 nm for 0.5 hours at room temperature to obtain a viscous crude product. The mixture was dialyzed for two days and circulated three times. The residual liquid in the dialysis bag was concentrated and dried to obtain the viscous product, a carboxyl-containing linear block copolymer, HMC-AC. The molar ratio of hexadecyl methacrylate to methacrylic acid was 3:1.

[0035] The structure of the carboxyl-containing linear block copolymer HMC-AC is as follows: Figure 2 As shown.

[0036] As in Example 1, a carboxyl-containing linear block copolymer (HMC-AC) was added to JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0037] Comparative Example 4: Commercial dispersant polyisobutylene succinimide (PIBSI) As in Example 1, the commercial dispersant polyisobutylene succinimide (PIBSI) was added to the JP-10 oxidation solution, and the morphology and UV transmittance of the oxidation solution were observed every two hours.

[0038] The UV transmittance of the oxidation residue containing different copolymers was tested every 2 hours (e.g., Figure 3 and Figure 4 The results showed that, after 8 hours of standing, the hyperbranched block copolymer HMC-AM containing amine groups exhibited the highest dispersion efficiency for soluble macromolecular oxidizing active substances, significantly exceeding that of linear block copolymers containing amine, hydroxyl, and carboxyl groups, as well as the commercial dispersant PIBSI. This is because the hyperbranched structure contains a greater number of functional groups than the linear structure, resulting in more active sites that can exert their effect. Under the same block ratio, amine groups contain more active hydrogens, thus forming more hydrogen bonds with soluble macromolecular oxidizing active substances, leading to stronger adsorption between the polymer and the soluble macromolecular oxidizing active substances. The soluble macromolecular oxidizing active substances can be uniformly dispersed in the fuel medium without aggregation or sedimentation, resulting in lower UV transmittance.

[0039] like Figure 5 As shown, the thermal stability of copolymers with different structures obtained in Examples 1-4 and Comparative Examples 2-3 was analyzed by thermogravimetric comparison. Hyperbranched block copolymers exhibit higher rigidity than linear structures, possessing a highly branched three-dimensional network with densely packed and interwoven side chains, which greatly restricts the thermal movement of molecular chains. This restricted movement makes the copolymers more difficult to thermally degrade at high temperatures, thus exhibiting relatively the best thermal stability. Figure 5）。

Claims

1. The application of a block copolymer in hydrocarbon fuel detergent dispersants, wherein the block copolymer is polyalkyl methacrylate-acrylamide, and the block copolymer is a hyperbranched block copolymer or a linear block copolymer.

2. The application according to claim 1, characterized in that, The molar ratio of alkyl methacrylate to acrylamide in the block copolymer is 2-4:

1.

3. The application according to claim 1, characterized in that, The block copolymer is a hyperbranched block copolymer of polyalkyl methacrylate-acrylamide.

4. The application according to claim 1, characterized in that, The block copolymer is prepared by: mixing alkyl methacrylate, acrylamide, and a photoinitiator in an organic solvent and then carrying out a photoinitiated free radical polymerization reaction to obtain a linear block copolymer polyalkyl methacrylate-acrylamide; or, mixing alkyl methacrylate, acrylamide, a photoinitiator, and a branching agent in an organic solvent and then carrying out a photoinitiated free radical polymerization reaction to obtain a hyperbranched block copolymer polyalkyl methacrylate-acrylamide.

5. The application according to claim 4, characterized in that, The branching agent is pentaerythritol tetraacrylate, and the amount of the branching agent added is 8-12% of the total mass of alkyl methacrylate and acrylamide.

6. The application according to claim 4, characterized in that, The amount of photoinitiator added is 0.5 to 1.5% of the total mass of alkyl methacrylate and acrylamide.

7. The application according to claim 4, characterized in that, The ultraviolet-visible light emitted during the photo-initiated free radical polymerization reaction has a wavelength of 320-600 nm, and the ultraviolet-visible light irradiation time is 0.5 hours to 2 hours.

8. The application according to claim 4, characterized in that, The organic solvent is toluene or xylene, and the photoinitiator is diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide.

9. The application according to claim 1, characterized in that, The alkyl methacrylate has 10 to 18 alkyl groups in its side chain.

10. The application according to claim 1, characterized in that, The hydrocarbon fuel is a hanging tetrahydrodicyclopentadiene JP-10.

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