Alcohol-soluble bio-based citronella polymers, methods of making and using the same

Abstract

This application belongs to the field of bio-based polymers, and more specifically, relates to an alcohol-soluble bio-based citronellol polymer, its preparation method, and its applications. This invention addresses the challenge that the trisubstituted olefin bonds in citronellol cannot directly participate in polymerization reactions. It utilizes a one-step strategy to convert the citronellol into olefin monomers via photo-oxidation. Then, based on room-temperature photoinduced electron transfer-reversible addition / chain scission polymerization technology, a polymer with controllable molecular weight, narrow dispersion, and abundant polar groups in the side chains is obtained. Finally, an alcohol-soluble resin-based environmentally friendly coating is developed, and the functional applications of the coating film are expanded by doping with inorganic fillers. This invention not only opens up a new green transformation pathway for the high-value utilization of citronellol containing trisubstituted olefin bonds, but also creates a high-performance, fully bio-based environmentally friendly functional coating based on this alcohol-soluble resin.

Description

Technical Field

[0001] This application belongs to the field of bio-based polymers, and more specifically, relates to an alcohol-soluble bio-based citronella polymer, its preparation method, and its application. Background Technology

[0002] Citronellol is a major component of the essential oils of more than 70 Rosaceae plants, possessing a sweet, rose-like aroma. Its structural formula is as follows: Figure 1 As shown. Although this compound has been industrially produced, its downstream industries have long been limited to basic fragrances and essential oils in the daily chemical / food industries, and it has been unable to break through the technological bottleneck of high-value utilization. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this application is to provide an alcohol-soluble bio-based citronellol polymer, its preparation method, and its application, aiming to open up a new technical path for the high-value utilization of citronellol.

[0004] To achieve the above objectives, in a first aspect, this application provides an alcohol-soluble bio-based citronella polymer having the general structural formula shown in formula (I):

[0005] Formula (1) Where n is an integer between 81 and 203.

[0006] Secondly, a method for preparing the alcohol-soluble bio-based citronella polymer is provided, comprising the following steps: (1) Citronellol is used as a raw material. Under the presence of photosensitizer and solvent, light is applied and photo-oxidation reaction occurs under the action of singlet oxygen to convert the citronellol into isopropenyl ketone monomer. (2) The alcohol-soluble bio-based citronella polymer was prepared by mixing isopropenyl ketone monomer, photosensitizer, RAFT reagent and solvent under light conditions via PET-RAFT polymerization.

[0007] Thirdly, an alcohol-soluble resin-based environmentally friendly coating based on the aforementioned bio-based citronella polymer is provided.

[0008] Preferably, the coating comprises an alcohol-soluble resin solution of the bio-based citronella polymer and an inorganic filler; the alcohol-soluble resin solution is obtained by dissolving the bio-based citronella polymer in an alcohol solvent.

[0009] More preferably, the inorganic filler is selected from one or more of oil-soluble pigments, Fe3O4 nanoparticles, rare earth particles, and Ag powder.

[0010] To establish a novel method for biomass conversion and enrich the application scenarios of bio-based materials, this invention employs a one-step strategy to convert citronellol into isopropenyl ketone monomers, and then obtains an alcohol-soluble resin through photoinduced electron transfer-reversible addition / fragmentation chain transfer (PET-RAFT) polymerization, demonstrating its potential application in the coatings field. Overall, compared with existing technologies, the above-described technical solution conceived in this application has the following beneficial effects: (1) This invention utilizes singlet oxygen to convert the chemically inert trisubstituted olefin bonds in citronellol molecules into unsaturated ketone groups in one step, thereby opening up a technical route for the conversion of the natural product citronellol into olefin monomers. Furthermore, alcohol-soluble bio-based citronellol polymers with controllable molecular weight and narrow dispersion are obtained through PET-RAFT polymerization, and the potential applications of alcohol-soluble resin / inorganic filler composites in the field of functional coatings are explored.

[0011] (2) The environmentally friendly characteristics of the alcohol-soluble resin prepared by the present invention are not only reflected in the fact that the resin and ethanol can be miscible in an infinite proportion, but also that it is a true 100% bio-based polymer material.

[0012] (3) The preparation method of the functional environmentally friendly coating described in this invention is applicable to micro-nano particles of almost any material, demonstrating good versatility. The side chains of the bio-based citronella polymer are rich in polar functional groups such as carbonyl and hydroxyl groups, thus they can be miscible with ethanol in any proportion at room temperature, significantly enhancing the environmental properties of the coating. Moreover, the above-mentioned groups also help to enhance the interaction between the paint film and the substrate, thereby improving the adhesion and durability of the paint film. In addition, there are a large number of interaction sites between the resin and the inorganic filler, so the uniform dispersion of the inorganic filler in the resin matrix can be achieved by simple high-speed vortex technology. It should be noted that micro-nano particles of different materials endow the functional paint film with flexible and adjustable physicochemical properties, which undoubtedly lays a solid foundation for customized bio-based environmentally friendly coatings. This invention clears away the technical obstacles for the development of high-performance environmentally friendly functional coatings. The preparation method has the advantages of simple process, low cost, safety and hygiene, and is expected to have broad practical prospects in the printing, construction, and home furnishing industries. Attached Figure Description

[0013] Figure 1 This is the molecular structure diagram of citronellol.

[0014] Figure 2 This is a schematic diagram of the route for synthesizing alcohol-soluble resins using citronellol as a raw material, as described in this application.

[0015] Figure 3 isopropenyl ketone monomer 1 1H NMR spectrum (solvent: deuterated chloroform).

[0016] Figure 4GPC curves, molecular weight information, and flight mass spectra of polymers P1-P3 prepared in Examples 4 to 6.

[0017] Figure 5 Photographs of the phosphorescent coating prepared in Example 7 under natural light and ultraviolet light.

[0018] Figure 6 Photograph of the magnetic coating prepared in Example 8 and its attraction by a magnet.

[0019] Figure 7 A photograph showing how the conductive coating prepared in Example 9 can replace a wire to connect a circuit.

[0020] Figure 8 A route diagram for preparing alcohol-soluble bio-based polyisopropyl ketone for Comparative Example 1. Detailed Implementation To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] This invention aims to open up a completely new technical path for the high-value utilization of citronellol. Citronellol contains trisubstituted olefin bonds (such as...) Figure 1 As shown), due to its reactivity and steric hindrance, this compound cannot directly participate in polymerization reactions as a monomer. This invention innovatively utilizes singlet oxygen to convert citronellol into isopropenyl ketone monomers (such as...) in one step. Figure 2 As shown in the figure, polymers with controllable molecular weight and narrow dispersion are obtained through PET-RAFT polymerization, and the potential applications of alcohol-soluble resin / inorganic filler composites in the field of functional coatings are explored.

[0022] Specifically, the present invention provides an alcohol-soluble bio-based citronella polymer having the general structural formula shown in formula (I):

[0023] Formula (1) Where n is an integer between 81 and 203.

[0024] The present invention also provides a method for preparing the alcohol-soluble bio-based citronella polymer, comprising the following steps: (1) Citronellol is used as a raw material. Under the presence of photosensitizer and solvent, light is applied and photo-oxidation reaction occurs under the action of singlet oxygen to convert the citronellol into isopropenyl ketone monomer. (2) The alcohol-soluble bio-based citronella polymer was prepared by mixing isopropyl ketone monomer, photosensitizer, RAFT reagent and solvent under light conditions via PET-RAFT (photoinduced electron transfer-reversible addition / chain scission) polymerization reaction.

[0025] In some embodiments, the photosensitizers described in steps (1) and (2) are each independently one or more of the following: hematoporphyrin, phenothiazine, benzoyl ether, benzoyl ketal, dialkoxyacetophenone, acetophenone oxide, acylphosphine oxide, benzophenone, 4,4'-dimethylaminobenzophenone, thiozanone, thioxanthone, camphorol, diimidazole, thiophene, aryl diazonium salt, diaryl iodide compound, triaryl sulfide, eosin, phthalocyanine, and curcumin.

[0026] In some embodiments, the molar ratio of citronellol to photosensitizer in step (1) is 50 / 1-200 / 1; the molar ratio of isopropenyl ketone monomer to photosensitizer in step (2) is 2000 / 1-10000 / 1, and the molar ratio of isopropenyl ketone monomer to RAFT reagent is 50 / 1-200 / 1.

[0027] In some embodiments, the solvents described in steps (1) and (2) are each independently one or more of the following: water, acetic acid, acetone, acetonitrile, tert-butanol, methyl tert-butyl ether, di-tert-butyl-p-cresol, chloroform, cyclohexane, dichloroethane, dichloromethane, diethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dioxane, ethanol, ethyl acetate, methyl ethyl ketone, ethylene glycol, n-hexane, hexamethylphosphoryltriamine, nitromethane, n-heptane, pyridine, tetrahydrofuran, toluene, and triethylamine.

[0028] In a preferred embodiment, the illumination in steps (1) and (2) is independently performed as follows: illumination is performed at a wavelength of 360-530 nm and an irradiation distance of 0.5-2.0 cm; wherein the photo-oxidation reaction in step (1) takes 12-48 h; and the PET-RAFT polymerization in step (2) takes 12-48 h.

[0029] In some embodiments, LED lights can be used to perform the photoreaction within the aforementioned wavelength range under dark environments and protective atmosphere conditions.

[0030] The RAFT reagent mentioned in step (2) of this invention can be 2-[(ethylthio)carbonylthio]thio]-2-methylpropionic acid, bis(carboxymethyl)trithiocarbonate, 2-[[(butylthio)thiooxymethyl]thio]propionic acid, 2,2'-[thiocarbonylbis(thionidyl)]dipropionic acid, 2-[[(2-carboxyethyl)thioalkylthiocarbonyl]-thioalkyl]propionic acid, 4-cyano-4-(((ethylthio)thiocarbonyl)thio)valerate, 3-benzylthioalkylthiocarbonylthioalkylpropionic acid, or 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid] cyanomethyl dodecyl carbonyl carbon trithiocarboxylate, 2-cyano-2-propyl dodecyl trithiocarbonate, 3,3'-[(dithionyl-1,2-dithiocarbonyl)bis(thionidyl)]dipropionic acid, 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, benzyl dodecyl trithiocarbonate, methyl 2-[[(dodecylmercapto)thiomethyl]thio]-2-methylbenzoate, 4-cyano-4-[[(dodecylthio)thionylmethyl]thio]valeric acid, 2-dodecyl thiocarbonyl thio-2-methylpropionic acid N -Hydroxysuccinimide ester, bis(dodecylthioalkylthiocarbonyl) disulfide, (2-hydroxyethyl) benzyl trithiocarbonate, 2-mercapto-S-thiobenzoylacetic acid, 2-cyano-2-propylbenzodisulfide, benzyl dithiobenzoate, 2-phenylpropane thiobenzoic acid ester, 4-cyano-4-(thiobenzoylthio)valerate, bis(thiobenzoyl) disulfide, 4-cyano-4-(phenylthiocarbonylthio)valerate- N - Succinimide ester, Rhodanine, 3-Ethyl-2-thiothiazolin-4-one, 3-Carboxymethyl rotanine, 3-(4-oxo-2-thiothiazolin-3-yl)propionic acid, Methyl(phenyl)aminodithiocarboxylic acid cyanomethyl ester, 3-Benzyl rotanine, benzyl diethyldithiocarboxylic acid ester, Tetramethylthiuram disulfide, Tetraethylthiuram disulfide, Tetraisopropylthiuram disulfide, p-phenylenedimethyl bis( N , N One or more of the following: diethyl dithiocarbamate, tetrabutylthiuram disulfide, tetrabenzylthiuram disulfide, etc.

[0031] In some embodiments, the crude product obtained after the photo-oxidation reaction in step (1) is separated by silica gel column chromatography (eluents are petroleum ether and ethyl acetate) to obtain a colorless, transparent, oily liquid. The structure and purity of the obtained isopropenyl ketone monomer are characterized using nuclear magnetic resonance (NMR). In a preferred embodiment, the volume ratio of petroleum ether to ethyl acetate is 20 / 1 to 1 / 1. The yield of the isopropenyl ketone monomer is 70%-90%.

[0032] In some embodiments, the crude product obtained from the PET-RAFT polymerization reaction in step (2) was precipitated multiple times in cold methanol, centrifuged, and vacuum dried to obtain a colorless, transparent, highly viscous liquid. The structure and molecular weight of the polymer product were characterized by time-of-flight mass spectrometry (MALDI-TOF-MS) and gel permeation chromatography (GPC), respectively. In a preferred embodiment, the yield of the bio-based citronella polymer was 70%-90%. At the beginning of the experiment, the inventors also tried to use methods such as... Figure 8 The synthetic route shown is used to synthesize alcohol-soluble bio-based polyisopropyl ketone. The preparation process involves as many as six steps, which is cumbersome and results in a very low actual yield of only 18-26%.

[0033] The present invention also provides an alcohol-soluble resin-based environmentally friendly coating based on the aforementioned bio-based citronella polymer.

[0034] The alcohol-soluble resin environmentally friendly coating provided by the present invention comprises an alcohol-soluble resin solution of the bio-based citronella polymer and an inorganic filler; the alcohol-soluble resin solution is obtained by dissolving the bio-based citronella polymer in an alcohol solvent, including but not limited to anhydrous ethanol.

[0035] In some embodiments, the alcohol-soluble resin solution has a mass fraction of 5-25%, and the alcohol solvent is ethanol. The inorganic filler is selected from one or more of oil-soluble pigments, Fe3O4 nanoparticles, rare earth particles, and Ag powder.

[0036] In some embodiments, the preparation method of the environmentally friendly coating includes the following steps: dissolving the bio-based citronella polymer in an alcohol solvent and stirring at room temperature to obtain a homogeneous solution. Subsequently, the inorganic filler is added to the aforementioned solution, and after mixing, the environmentally friendly coating is obtained.

[0037] In some embodiments, the environmentally friendly coating is obtained by mixing using a vortex mixer. This coating is then brushed onto a substrate and dried at room temperature for 24-36 hours to obtain a functional coating. The substrate material can be selected from a range of materials including plastics, glass, metals, wood, and ceramics. The film thickness is 40-60 μm.

[0038] In some embodiments, the mass ratio of the inorganic filler to the alcohol-soluble resin is 1 / 10 to 1 / 2.

[0039] The LED lamp used in this embodiment of the invention is model GCH-4; manufacturer: Wuhan Jiushang Technology Co., Ltd.

[0040] The vortex mixer used in this embodiment of the invention is model XWY-2, manufactured by Ningbo Kemai Instrument Co., Ltd.

[0041] The preparation method of the functional environmentally friendly coating described in this invention is applicable to micro-nano particles of almost any material, exhibiting excellent versatility. The side chains of the bio-based citronella polymer are rich in polar functional groups such as carbonyl and hydroxyl groups, thus allowing it to be miscible with ethanol in any proportion at room temperature, significantly enhancing the environmental properties of the coating. Furthermore, these functional groups also help enhance the interaction between the paint film and the substrate, thereby improving the adhesion and durability of the paint film. In addition, there are numerous interaction sites between the resin and the inorganic filler; therefore, the uniform dispersion of the inorganic filler in the resin matrix can be achieved using a simple high-speed vortex technique. It should be noted that micro-nano particles of different materials endow the functional paint film with flexible and adjustable physicochemical properties, which undoubtedly lays a solid foundation for customized bio-based environmentally friendly coatings. This invention clears the technical obstacles for the development of high-performance environmentally friendly functional coatings. The preparation method has advantages such as simple process, low cost, and safety and hygiene, and is expected to have broad practical prospects in industries such as printing, construction, and home furnishing.

[0042] The bio-based citronella polymer provided by this invention has the following technical advantages over commercially available products: 1) It is a 100% pure bio-based material, while most commercially available products are petrochemical-based polymer coatings. The raw material source of the bio-based citronella polymer of this invention is greener and more environmentally friendly; 2) The bio-based citronella polymer involved in this invention is alcohol-soluble, so ethanol can be used as a solvent, exhibiting excellent environmental protection properties. Commercially available products have an odor because they contain organic solvents, which are harmful to both humans and the environment; 3) The side chains of the bio-based citronella polymer involved in this invention contain a large number of ketone carbonyl groups and alcohol hydroxyl groups. These polar groups have strong interactions with the substrate material, which helps to improve the stability of the coating.

[0043] This invention addresses the challenge of citronellol's trisubstituted olefin bonds not directly participating in polymerization reactions by employing a one-step strategy using photo-oxidation to convert them into olefin monomers. Secondly, based on room-temperature photoinduced electron transfer-reversible addition / fragmentation chain transfer (PET-RAFT) polymerization technology, polymers with controllable molecular weight, narrow dispersion, and abundant polar side chains are obtained. Finally, alcohol-soluble resin-based environmentally friendly coatings are developed, and the functional applications of the coating film are expanded by doping with inorganic fillers. This invention not only opens up a new green transformation pathway for the high-value utilization of numerous terpenoid compounds containing trisubstituted olefin bonds, but also creates high-performance, fully bio-based environmentally friendly functional coatings based on alcohol-soluble resins.

[0044] The embodiments of the present invention are implemented based on the technical solution of the present invention, and detailed implementation methods and processes are given. However, the scope of protection of the present invention is not limited to the following embodiments. Process parameters in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0045] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0046] The process parameters in the following examples, unless otherwise specified, are generally performed under conventional conditions.

[0047] The analysis and testing methods involved in the embodiments of this invention are as follows: (1) Nuclear magnetic resonance hydrogen spectrum ( 1 H NMR) The isopropenyl ketone monomer was dissolved in deuterated chloroform (CDCl3), and tetramethylsilyl (TMS) was used as an internal standard for chemical shift. The sample's chemical shift was determined using a Bruker Avance 400 nuclear magnetic resonance spectrometer. 1 1H NMR (400 MHz) spectrum.

[0048] (2) Time-of-flight mass spectrometry (MALDI-TOF-MS) Matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of polymers was performed using a Bruker Ultraflextreme mass spectrometer. The spectrometer was equipped with a 355 nm Nd:YAG laser operating in positive ion linear mode. The analyzer was used at an accelerating voltage of +20 kV. The laser was focused onto the sample using an 8.02 kV lens. Pulse ion extraction was optimized to 170 ns. The sample was prepared using a THF solution (concentration 10 mg / mL). -1 ), trans THF solution of 2-[3-(4-tert-butylphenyl)-2-methyl-2-propenyl]malonidium (DCTB) (concentration 50 mg / mL) -1 ) and sodium trifluoroacetate aqueous solution (concentration 5 mg / mL) -1 The sample was mixed at a 4 / 4 / 1 volume ratio, and then 1 μL of sample was deposited onto a target plate, dried, and tested. MALDI-TOF-MS ensured detection in 10 different sample deposition areas, providing a total of 500 lenses. Data acquisition and processing were performed using FlexControl 3.4 software.

[0049] (3) Gel permeation chromatography (GPC) The number-average molecular weight of polymers was measured using a polymer laboratory gel permeation chromatography (PL GPC50) equipped with three PL gel mixing C-columns. Mn ) and dispersion ( Ð Each injection was of a polymer solution (100 μL, with a concentration of 1 mg / mL in THF). -1 ). In THF (flow rate: 1 mL min) -1 In 35 o Measurements were performed at C using a Waters 1525 binary HPLC pump equipped with a Waters 2414 refractive index detector. Several narrow-dispersion polystyrene ( M n = 1.3-900.0kDa; Ð = 1.06-1.10) was used as an internal standard, and calculations were performed using Breeze 3.30 SPA software. M n and Ð value.

[0050] The embodiments of this application are described below with reference to the accompanying drawings.

[0051] Examples 1 to 3 are examples of the synthesis and characterization of isopropenyl ketone monomers.

[0052] Example 1 Weigh 156.3 mg (1 mmol) of citronellol and 5.1 mg (10 μmol) of phthalocyanine using a precision balance, and transfer them sequentially to 25 mL straight-sided Schlenk flasks. Add 1 mL of anhydrous acetonitrile and stir to obtain a homogeneous reaction solution. Place the Schlenk flask in a photoreactor, and in the dark, turn on the LED light (…). λ = 365 nm, irradiation distance approximately 1 cm), stirred at room temperature for 24 h. The solvent was evaporated, and the crude product was separated by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1) to obtain a colorless, transparent oily liquid. Yield: 86%. The isopropenyl ketone monomer prepared in Example 1... 1 H NMR spectrum as shown Figure 3 As shown.

[0053] 1 H NMR (400 MHz, CDCl3) δ = 5.93 (s, 1H), 5.72 (s, 1H), 3.59-3.67 (m,2H), 2.66 (t, J = 10 Hz, 2H), 2.54 (s, 1H), 1.80 (s, 3H), 1.50-1.65 (m, 3H), 1.31-1.40 (m, 2H), 0.85 (d, J = 8.8 Hz, 3H). Example 2 Weigh 156.3 mg (1 mmol) of citronellol and 15.3 mg (10 μmol) of 5,10,15,20-tetra(4-trimethylamino)phenylporphyrin tetratoluenesulfonate separately using a precision balance, and transfer them sequentially to 25 mL straight-sided Schlenk flasks. Add 1 mL of anhydrous acetonitrile to each flask, and stir to obtain a homogeneous reaction solution. Place the Schlenk flask in a photoreactor, and in the dark, turn on the LED light (…). λ = 365 nm (irradiation distance approximately 1 cm), stirred at room temperature for 24 h. The solvent was evaporated, and the crude product was separated by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1) to obtain a colorless, transparent oily liquid. Yield: 75%.

[0054] Example 3 Weigh 156.3 mg (1 mmol) of citronellol and 3.7 mg (10 μmol) of curcumin using a precision balance, and transfer them sequentially to 25 mL Schlenk flasks. Add 1 mL of anhydrous acetonitrile and stir to obtain a homogeneous reaction solution. Place the Schlenk flask in a photoreactor, and in the dark, turn on the LED light (…). λ = 365 nm (irradiation distance approximately 1 cm), stirred at room temperature for 24 h. The solvent was evaporated, and the crude product was separated by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1) to obtain a colorless, transparent oily liquid. Yield: 81%.

[0055] Examples 4 to 6 are examples of the preparation and characterization of bio-based lemongrass polymers.

[0056] Example 4 85.1 mg (0.5 mmol) of isopropenyl ketone monomer and 0.1 mg (0.2 μmol) of eosin Y were weighed separately using a precision balance and transferred to 25 mL straight-sided Schlenk flasks. Under argon protection, 3.7 mg (10 μmol) of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and 0.5 mL of anhydrous dimethyl sulfoxide were added sequentially. After three cycles of freezing-vacuuming-thawing, the polymerization system was sealed. The Schlenk flask was placed in a photoreactor, and in the dark, the LED light was turned on. λ = 465nm (irradiation distance approximately 1 cm), stirred at room temperature for 24 h. After polymerization, the crude product was diluted with a small amount of dichloromethane and eosin Y was removed by passing it through an alkaline alumina column. After rotary evaporation and concentration, the resulting viscous solution was precipitated three times in cold methanol, and after centrifugation and drying, a colorless, transparent, highly viscous liquid P1 was obtained. Yield: 90%.

[0057] Example 5 170.3 mg (1 mmol) of isopropenyl ketone monomer and 0.1 mg (0.2 μmol) of eosin Y were weighed using a precision balance and transferred sequentially to 25 mL straight-sided Schlenk flasks. Under argon protection, 3.7 mg (10 μmol) of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and 0.5 mL of anhydrous dimethyl sulfoxide were added sequentially. After three cycles of freezing-vacuuming-thawing, the polymerization system was sealed. The Schlenk flask was placed in a photoreactor, and in the dark, the LED light was turned on. λ = 465nm (irradiation distance approximately 1 cm), stirred at room temperature for 24 h. After polymerization, the crude product was diluted with a small amount of dichloromethane and eosin Y was removed by passing it through an alkaline alumina column. After rotary evaporation and concentration, the resulting viscous solution was precipitated three times in cold methanol, and after centrifugation and drying, a colorless, transparent, highly viscous liquid P2 was obtained. Yield: 84%.

[0058] Example 6 340.5 mg (2 mmol) of isopropenyl ketone monomer and 0.1 mg (0.2 μmol) of eosin Y were weighed using a precision balance and transferred sequentially to 25 mL straight-sided Schlenk flasks. Under argon protection, 3.7 mg (10 μmol) of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid and 0.5 mL of anhydrous dimethyl sulfoxide were added sequentially. After three cycles of freezing-vacuuming-thawing, the polymerization system was sealed. The Schlenk flask was placed in a photoreactor, and in the dark, the LED light was turned on. λ = 465nm (irradiation distance approximately 1 cm), stirred at room temperature for 24 h. After polymerization, the crude product was diluted with a small amount of dichloromethane and eosin Y was removed by passing it through an alkaline alumina column. After rotary evaporation and concentration, the resulting viscous solution was precipitated three times in cold methanol, and after centrifugation and drying, a colorless, transparent, highly viscous liquid P3 was obtained. Yield: 78%.

[0059] GPC curves, molecular weight information, and flight mass spectra of polymers P1-P3 are shown below. Figure 4 As shown.

[0060] Depend on Figure 4 It is known that isopropyl ketone monomers can be polymerized via PET-RAFT to produce bio-based citronellol polymers with high molecular weight and narrow dispersion. The theoretical degree of polymerization of the product can be easily adjusted by controlling the ratio of monomer to chain transfer agent. Verification has shown that resin samples of different molecular weights are miscible with ethanol in any proportion at room temperature.

[0061] Examples 7 to 9 are examples of the preparation of alcohol-soluble resin-based environmentally friendly coatings.

[0062] Example 7 0.8 g of bio-based citronella polymer P3 was dissolved in 5 mL of anhydrous ethanol and stirred at room temperature for 5 min to obtain a homogeneous solution. Subsequently, 0.4 g of micron-sized particles containing terbium / europium were added to the aforementioned solution, and the mixture was vortexed for 10 min to obtain an environmentally friendly coating. This coating was brushed onto the surface of a polypropylene sheet and dried in air at room temperature for 24 h to obtain a phosphorescent coating. Figure 5 As shown, after ultraviolet light ( λ Excitation with a UV light source (365 nm) resulted in strong phosphorescence in the coating under dark conditions. After removal of the UV light source, the phosphorescence intensity gradually decreased within 3 seconds. Content (A) shows a photograph of the phosphorescent coating under natural light, and content (B) shows a photograph of the phosphorescent coating under UV light.

[0063] Example 8 0.8 g of bio-based citronella polymer P3 was dissolved in 5 mL of anhydrous ethanol and stirred at room temperature for 5 min to obtain a homogeneous solution. Subsequently, 0.16 g of Fe3O4 nanoparticles were added to the aforementioned solution, and the mixture was vortexed for 10 min to obtain an environmentally friendly coating. This coating was brushed onto the surface of a polypropylene sheet and dried in air at room temperature for 24 h to obtain a magnetic coating. Figure 6 As shown, a magnet can easily pick up the coated polymer sheet. Content (A) is a photo of the magnetic coating; content (B) shows the magnet picking up the polymer sheet.

[0064] Example 9 0.8 g of bio-based citronella polymer P3 was dissolved in 5 mL of anhydrous ethanol and stirred at room temperature for 5 min to obtain a homogeneous solution. Then, 0.24 g of Ag powder was added to the solution, and the mixture was vortexed for 10 min to obtain an environmentally friendly coating. This coating was brushed onto the surface of a polypropylene sheet and dried in air at room temperature for 24 h to obtain a conductive coating. Figure 7 As shown, after cutting the LED light's wires, connect the wire ends to both ends of the conductive coating. After turning on the power, the LED light can illuminate normally.

[0065] Comparative Example 1 This comparative example provides another method for synthesizing alcohol-soluble bio-based polyisopropyl ketones. The synthetic route is shown below. Figure 8 As shown, it includes the following steps: Figure 8 In step a, the reaction conditions are: 1.1 equivalents of tert-butyldiphenylchlorosilane and 1.5 equivalents of imidazole, in a solvent of... N , N -Dimethylformamide, reacted at room temperature for 1 hour, yielded 99%.

[0066] The reaction conditions for step b were: 1.05 equivalents of m-chloroperoxybenzoic acid, reaction at 0°C for 0.5 h, yield 93%.

[0067] The reaction conditions for step c were: 1.05 equivalents of aluminum isopropoxide, toluene as solvent, reaction at 115℃ for 8 hours; pH was adjusted to 1-2 using 1 mol / L hydrochloric acid solution, and the reaction yield was 89%.

[0068] The reaction conditions for step d were: 1.1 equivalents of o-iodobenzoic acid, with dimethyl sulfoxide and tetrahydrofuran as solvents, and the reaction was carried out at room temperature for 2 hours, with a yield of 87%.

[0069] The reaction conditions for step e were: 0.01 equivalents of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, 0.0002 equivalents of eosin Y, dimethyl sulfoxide as solvent, LED light source with a wavelength of 465 nm, room temperature, 24 h, yield 89%.

[0070] The reaction conditions for step f were: 1.5 equivalents of tetrabutylammonium fluoride, tetrahydrofuran solvent, room temperature, 24 h, with a yield of 35%.

[0071] The overall yield from steps a to f was 22%. It can be seen that the conventional approach to preparing alcohol-soluble bio-based polyisopropyl ketones is cumbersome and yields very low results.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An alcohol-soluble bio-based citronella polymer, characterized in that, It has a general structural formula as shown in equation (1): Formula (1) Where n is an integer between 81 and 203.

2. The method for preparing the alcohol-soluble bio-based citronella polymer as described in claim 1, characterized in that, Includes the following steps: (1) Citronellol is used as a raw material and is subjected to light irradiation in the presence of photosensitizer and solvent. Under the action of singlet oxygen, the photo-oxidation reaction is carried out to convert the citronellol into isopropenyl ketone monomer. (2) The alcohol-soluble bio-based citronella polymer was prepared by mixing isopropenyl ketone monomer, photosensitizer, RAFT reagent and solvent under light conditions via PET-RAFT polymerization.

3. The preparation method according to claim 2, characterized in that, The photosensitizers mentioned in steps (1) and (2) are one or more of the following: hematoporphyrin, phenothiazine, benzophenone, 4,4'-dimethylaminobenzophenone, memidazole, eosin, phthalocyanine, and curcumin.

4. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of citronellol to photosensitizer is 50:1-200:1; in step (2), the molar ratio of isopropenyl ketone monomer to photosensitizer is 2000:1-10000:1, and the molar ratio of isopropenyl ketone monomer to RAFT reagent is 50:1-200:

1.

5. The preparation method according to claim 2, characterized in that, The solvents used in steps (1) and (2) are one or more of the following: acetone, acetonitrile, tert-butanol, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dioxane, ethanol, ethyl acetate, methyl ethyl ketone, ethylene glycol, hexamethylphosphoric triamine, nitromethane, tetrahydrofuran, and toluene.

6. The preparation method according to claim 2, characterized in that, The illumination described in steps (1) and (2) is performed under the condition of a wavelength of 360-530 nm and an illumination distance of 0.5-2.0 cm; The photo-oxidation reaction in step (1) takes 12-48 hours; the PET-RAFT polymerization in step (2) takes 12-48 hours.

7. The preparation method according to claim 2, characterized in that, The RAFT reagent in step (2) is 2-[(ethylthio)carbonylthio]thio]-2-methylpropionic acid, 2-[[(butylthio)thiooxymethyl]thio]propionic acid, 2-[[(2-carboxyethyl)thioalkylthiocarbonyl]-thioalkyl]propionic acid, 4-cyano-4-(((ethylthio)thiocarbonyl)thio)valerate, 3-benzylthioalkylthiocarbonylthioalkylpropionic acid, cyanomethyl dodecyl carbonyl trithiocarboxylate, 2-cyano-2-propyl dodecyl trithiocarbonate, 2-[dodecylthio(thiocarbonyl)] The following are some of the following: [[(dodecylthio)thiomethyl]-2-methylpropionic acid, benzyl dodecyl trithiocarbonate, methyl 2-[[(dodecylthio)thiomethyl]thio]-2-methylbenzoate, 4-cyano-4-[[(dodecylthio)thionylmethyl]thio]valeric acid, (2-hydroxyethyl) benzyl trithiocarbonate, 2-mercapto-S-thiobenzoylacetic acid, 2-cyano-2-propylbenzodisulfide, benzyl dithiobenzoate, thiobenzoic acid-2-phenylpropane thioester, and 4-cyano-4-(thiobenzoylthio)valeric acid.

8. An alcohol-soluble resin-based environmentally friendly coating based on the bio-based citronella polymer as described in claim 1.

9. The coating as described in claim 8, characterized in that, The alcohol-soluble resin solution comprising the bio-based citronella polymer as described in claim 1 further comprises inorganic filler; the alcohol-soluble resin solution is obtained by dissolving the bio-based citronella polymer in an alcohol solvent.

10. The coating as described in claim 9, characterized in that, The inorganic filler is selected from one or more of oil-soluble pigments, Fe3O4 nanoparticles, rare earth particles, and Ag powder.

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