Self-stabilization precipitation polymerization method of Fischer-Tropsch synthesis product

Abstract

The invention relates to a self-stabilization precipitation polymerization method of a Fischer-Tropsch synthesis product. The self-stabilizing precipitation polymerization method comprises the following steps: carrying out self-stabilizing precipitation polymerization on a reaction system containing a Fischer-Tropsch synthesis product, an electron-accepting monomer, a polar monomer, an initiator and a solvent; the polar monomer is selected from at least one of vinyl acetate, glycidyl methacrylate and methyl methacrylate; the Fischer-Tropsch synthesis product comprises alpha-olefin. The method is simple in process and low in cost, the product can be obtained through direct centrifugation or filtration subsequently, the product yield is high, and engineering amplification is easy; polymerization products are uniform and stable microsphere particles, and later modification and application are facilitated; allowing polymerization at higher and wider ranges of monomer concentrations; the environment is protected.

Description

Technical Field

[0001] The invention belongs to the field of polymer synthesis, and in particular relates to a self-stabilizing precipitation polymerization method for a Fischer-Tropsch synthesis product. Background Art

[0002] Indirect coal liquefaction technology uses coal as a raw material, first reacting it with oxygen and water vapor to reduce its sulfur and carbon content, thereby converting it into clean synthesis gas (CO and H2). This is then processed through Fischer-Tropsch synthesis to produce hydrocarbons. This is then further hydrorefined and separated in an oil processing unit to produce fuel oils such as gasoline and diesel, or other chemical products. Therefore, indirect coal liquefaction is also known as Fischer-Tropsch synthesis technology.

[0003] Fischer-Tropsch synthesis products primarily include naphtha fractions, heavy oil fractions, and heavy waxes. They are composed of long-chain mixed α-olefins of varying carbon numbers (approximately 60%), normal alkanes, and oxygenates. They have extremely low sulfur and nitrogen content and are essentially free of cycloalkanes and aromatics. Their composition differs significantly from conventional petroleum. Traditionally, these olefins in Fischer-Tropsch synthesis products have been directly hydrotreated (hydrorefining, hydrocracking, separation, light oil recovery, etc.) to produce petrochemical feedstocks or transportation fuels that meet usage specifications. However, this development model has a single overall structure and directly competes with petrochemical and refining companies. It lacks the competitive advantage over petrochemical companies in the short term.

[0004] Patent document 1 discloses a method and system for producing diesel and lubricating oil base oils using Fischer-Tropsch synthesis products, wherein the full fraction of the Fischer-Tropsch synthesis product is hydrotreated to obtain diesel-I, naphtha and heavy oil; the heavy oil is hydroisomerized and cracked, hydrofined and stabilized, and distilled to obtain diesel-II and lubricating oil base oil.

[0005] Patent document 2 discloses an apparatus and method for hydrotreating Fischer-Tropsch synthesis products, which sequentially connects a separator, a reaction chamber, and a heavy oil tank from top to bottom to maximize the yield of high-quality fuel oil.

[0006] Extraction and separation of individual α-olefins is also an important way to increase the value of Fischer-Tropsch synthesis products. Key technologies include adsorption, extractive distillation, membrane separation, cryogenic separation, and molecular distillation. The most widely used individual α-olefins in industry are 1-butene, 1-hexene, and 1-octene, primarily copolymerized with ethylene to produce high-density polyethylene and linear low-density polyethylene to improve mechanical properties. Some C6-C10 α-olefins are used to produce plasticizer alcohols, C8-C12 α-olefins are used to generate synthetic base oils for polyα-olefin (PAO) lubricants, C10-C16 α-olefins are used to produce detergent alcohols and surfactants, and C16-C18 α-olefins are used as oilfield chemicals.

[0007] Patent documents 3 and 4 respectively disclose methods for preparing polymerization-grade 1-heptene and 1-octene from Fischer-Tropsch oil-washed naphtha, wherein the oil-washed naphtha is subjected to distillation, deoxygenation, etherification, distillation, and deoxygenation to obtain polymerization-grade 1-heptene; and high-purity 1-octene is obtained through secondary fractionation and cutting, extraction separation, water washing, adsorption, and distillation separation.

[0008] Patent Documents 5 and 6 disclose methods for separating 1-decene and 1-dodecene from Fischer-Tropsch stable heavy oil, respectively, wherein 1-decene and 1-dodecene are obtained by performing narrow fraction splitting, reaction, separation, reverse reaction, etc.

[0009] The energy barrier for free radical initiation of α-olefins is high, and the hydrogen atoms on the allylic groups of α-olefin monomers readily react with active centers to form chain transfer reactions, making it difficult to form high molecular weight polymers. α-olefins are electron-donating monomers that readily form charge-transfer complexes with electron-accepting monomers, enabling alternating copolymerization. Maleic anhydride is a typical electron-accepting monomer, and extensive research has been conducted on the free radical copolymerization of single α-olefins with maleic anhydride. The anhydride group is also a highly reactive functional group that can react with alcohols, amines, and other molecules to modify copolymers, expanding their application.

[0010] In non-patent documents 1 to 4, 1-hexene-maleic anhydride, 1-octene-maleic anhydride, 1-decene-maleic anhydride, 1-dodecene-maleic anhydride, 1-tetradecene-maleic anhydride, and 1-hexadecene-maleic anhydride copolymers are prepared by using initiators such as dibenzoyl peroxide and azobisisobutyronitrile, dioxane, toluene, acetone, etc. as reaction solvents, reacting at 65 to 70° C. for 4 to 12 hours, and using precipitants such as methanol and n-hexane.

[0011] Patent document 7 proposes that the electron-donating monomer and the electron-accepting monomer in the unseparated Fischer-Tropsch synthesis product be polymerized under the action of an initiator, thereby overcoming the problems of the complex composition, close boiling points and difficulty in separation of the Fischer-Tropsch synthesis product.

[0012] In Patent Document 8, low-carbon olefins, ethylene and / or propylene are used as the third monomer to increase the solubility parameters of the polymer, thereby realizing self-stabilizing precipitation polymerization of the Fischer-Tropsch synthesis product. Solid-liquid separation can be achieved through simple treatment, and the solvent in the supernatant obtained after separation can be recycled, and the remainder is unreacted long-chain alkanes.

[0013] References:

[0014] Patent Literature:

[0015] Patent Document 1: CN 110016363A;

[0016] Patent Document 2: CN 116064131A;

[0017] Patent Document 3: CN 118388311A;

[0018] Patent Document 4: CN 114409496A;

[0019] Patent Document 5: CN 114685235A;

[0020] Patent Document 6: CN 114644543A;

[0021] Patent Document 7: CN 117417481A;

[0022] Patent Document 8: CN 119285852A;

[0023] Non-patent literature:

[0024] Non-patent document 1: Maz1H et al., “Bioengineering functional copolymers. IX. poly[(maleic anhydride-co-hexene-1)-g-poly(ethylene oxide)]”, Macromolecular Bioscience, 2006, 6(4): 311-321.

[0025] Non-patent document 2: F et al., "Copolymerization of maleic anhydride with styrene and α-olefins. molecular and thermal characterization", Journal of Macromolecular Science, Part A, 2005, 42(8): 1063-1072.

[0026] Non-patent document 3: Amirilargani M et al., "Poly(maleic anhydride-alt-1-alkenes) directly grafted to γ-alumina for high-performance organic solvent nanofiltration membranes", Journal of Membrane Science, 2018, 564: 259-266.

[0027] Non-patent document 4: D et al., "Preparation of poly(MA-alt-α-olefin-C6,8,12,18) / silica nanohybrids via in situ generated nanofillers for use as a dualfunction organonanofiller", Journal of Chemical Sciences, 2015, 127(11): 1993-2003. Summary of the Invention

[0028] Problems to be solved by the invention

[0029] In non-patent documents 1 to 4 and patent document 7, due to the presence of long-chain α-olefins, the cohesive energy density of the polymer is low, and the polymerization process can only be solution polymerization. Alkyl alcohol must be used as a precipitant to separate the product, which is not conducive to large-scale production.

[0030] The polymerization reaction equipment in Patent Document 8 requires the use of a high-pressure reactor, which has high equipment costs and high requirements.

[0031] Furthermore, the inventors found in their previous studies that when copolymerizing α-olefins in the Fischer-Tropsch synthesis product with electron-accepting monomers, it was not possible to convert the copolymerization into precipitation polymerization by changing the solvent solubility parameters, monomer concentration, and increasing the molecular weight.

[0032] The object of the present invention is to provide a self-stabilizing precipitation polymerization method for α-olefins in Fischer-Tropsch synthesis products and electron-accepting monomers.

[0033] Solutions for solving problems

[0034] In response to the above problems, the present inventors conducted long-term and in-depth research and found that self-stabilizing precipitation polymerization of Fischer-Tropsch synthesis products can be achieved by introducing a specific polar monomer as the third monomer.

[0035] Specifically, the present invention solves the problems of the present invention by the following means.

[0036] [1] A self-stabilizing precipitation polymerization method comprising the following steps:

[0037] subjecting a reaction system comprising a Fischer-Tropsch synthesis product, an electron-accepting monomer, a polar monomer, an initiator, and a solvent to self-stabilizing precipitation polymerization;

[0038] The polar monomer is at least one selected from vinyl acetate, glycidyl methacrylate, and methyl methacrylate;

[0039] The Fischer-Tropsch synthesis product comprises α-olefins.

[0040] [2] The self-stabilizing precipitation polymerization method according to [1], wherein

[0041] The electron-accepting monomer is one or a combination of two or more selected from maleic anhydride, maleimide, itaconic anhydride and their derivatives;

[0042] The Fischer-Tropsch synthesis product is Fischer-Tropsch synthesis oil and / or Fischer-Tropsch synthesis wax;

[0043] The initiator is one or more selected from azo compound initiators and peroxide initiators;

[0044] The solvent is an organic solvent.

[0045] [3] The self-stabilizing precipitation polymerization method according to [2], wherein

[0046] The electron-accepting monomer is selected from maleic anhydride, itaconic anhydride, maleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-(1-naphthyl)maleimide, or a combination of two or more thereof;

[0047] The Fischer-Tropsch synthetic oil is Fischer-Tropsch synthetic oil-washed naphtha and / or Fischer-Tropsch synthetic stable heavy oil; the content of α-olefin in the Fischer-Tropsch synthetic product is 1 to 70% by mass;

[0048] The solvent is one or a combination of two or more selected from hydrocarbon solvents, ketone solvents, carboxylic acid ester solvents and ether solvents;

[0049] The azo compound initiator is azobisisobutyronitrile or azobisisoheptanenitrile;

[0050] The peroxide initiator is dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, or dicyclohexyl peroxydicarbonate.

[0051] [4] The self-stabilizing precipitation polymerization method according to any one of [1] to [3], wherein the solvent is one or more selected from amyl acetate, isoamyl acetate, acetone, butanone, methyl butyl ether, methyl isobutyl ether, methyl tert-butyl ether, methyl isoamyl ether, methyl tert-amyl ether, n-hexane, cyclohexane, toluene, and xylene.

[0052] [5] The self-stabilizing precipitation polymerization method according to any one of [1] to [3], wherein the total mass concentration of the α-olefin, the electron-accepting monomer, and the polar monomer in the reaction system is 10 to 70% by mass, preferably 20 to 60% by mass;

[0053] Based on the total mass of the α-olefin, the electron-accepting monomer and the polar monomer as 100%, the mass fraction of the polar monomer is 14 to 40 mass%, preferably 23 to 35 mass%;

[0054] The mass ratio of the electron-accepting monomer to the Fischer-Tropsch synthesis product is 1:30 to 5:1, preferably 1:8 to 2:1;

[0055] Based on the total mass of the α-olefin, the electron-accepting monomer and the polar monomer as 100%, the amount of the initiator used is 0.05 to 10% by mass, preferably 1 to 5% by mass.

[0056] [6] The self-stabilizing precipitation polymerization method according to any one of [1] to [3], wherein the electron-accepting monomer, initiator and solvent are mixed, and then the Fischer-Tropsch synthesis product and polar monomer are added, so that the resulting reaction system undergoes self-stabilizing precipitation polymerization.

[0057] [7] The self-stabilizing precipitation polymerization method according to any one of [1] to [3], wherein the self-stabilizing precipitation polymerization is carried out in an inert gas, the polymerization reaction temperature is 50 to 120° C., and the polymerization reaction time is 1 to 24 hours.

[0058] [8] The self-stabilizing precipitation polymerization method according to any one of [1] to [3], further comprising a step of post-treating the reaction system after the self-stabilizing precipitation polymerization, wherein the post-treatment preferably comprises one or a combination of two or more of solid-liquid separation, washing or drying.

[0059] [9] A copolymer obtained by the self-stabilizing precipitation polymerization method according to any one of [1] to [8].

[0060]

[10] The copolymer according to [9] is characterized in that the copolymer is copolymer microspheres with a number average particle size of 0.1 to 10 μm and a particle size distribution coefficient of 1.001 to 1.2.

[0061] Effects of the Invention

[0062] The method of the present invention has simple process and low cost. The product can be directly obtained by centrifugation or filtration, with high product yield and easy engineering scale-up. The polymerization product is uniform and stable microsphere particles, which are conducive to later modification and application. The method allows polymerization at higher and wider monomer concentrations and is environmentally friendly.

[0063] Specifically, the method of the present invention has the following beneficial effects:

[0064] 1. The method of the present invention is simple, the reaction conditions are mild, and the self-stabilizing precipitation polymerization of the Fischer-Tropsch synthesis product can be achieved by adding a small amount of specific polar monomers. The separation of the polymerization product is simple and the yield is high. The conversion rate of α-olefin is high, and the content of α-olefin units in the polymerization product is high.

[0065] 2. In the method of the present invention, the solvent, unreacted α-olefins and alkanes in the supernatant after separation can be recycled again, realizing green preparation.

[0066] 3. The method of the present invention can obtain polymer microspheres with controllable size, regular shape and high particle size uniformity. The yield and size of the microspheres can be adjusted by adjusting the monomer ratio, reaction time, monomer concentration, initiator concentration, etc.

[0067] 4. The preparation method of the present invention directly uses the Fischer-Tropsch synthesis product without further separation as raw material, and does not require refining and separation, and directly converts the mixed α-olefin fraction into a functional high-value polyolefin product, overcoming the problems of complex composition, close boiling points and difficult separation of the Fischer-Tropsch synthesis product, thereby greatly reducing costs.

[0068] 5. The copolymer obtained by the method of the present invention has a high content of functional groups brought by the electron-accepting monomer and the polar monomer, and the copolymer has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 1.

[0070] Figure 2 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 2.

[0071] Figure 3 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 3.

[0072] Figure 4 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 10.

[0073] Figure 5 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 14.

[0074] Figure 6 This is a scanning electron microscope photograph of the copolymer microspheres obtained in Example 15.

[0075] Figure 7 This is a scanning electron microscope photograph of the lower precipitate of Comparative Example 2.

[0076] Figure 8 This is a scanning electron microscope photograph of the lower precipitate of Comparative Example 3.

[0077] Figure 9 This is a scanning electron microscope photograph of the lower precipitate of Comparative Example 4.

[0078] Figure 10 The NMR carbon spectrum of the copolymer obtained in Example 1 is shown in FIG.

[0079] Figure 11 The DSC charts of the copolymers obtained in Examples 1 and 10 are shown.

[0080] Figure 12 (A) is a photograph of the copolymer obtained in Example 10.

[0081] Figure 12 (B) is a photograph of the copolymer obtained in Example 1. DETAILED DESCRIPTION

[0082] The following describes the technical features of the present invention in detail. The technical features described below are described based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples.

[0083] Terms and Definitions

[0084] In this specification, "Fischer-Tropsch synthesis product" refers to a product obtained by Fischer-Tropsch synthesis technology.

[0085] In this specification, "self-stabilized precipitation polymerization" refers to a polymerization method in which no stabilizer is used in the system and the polymerization product is stably dispersed in the system by "static polymerization".

[0086] In this specification, "particle size" refers to the number average particle size of the particles being described, which can be obtained by the method described in the Examples section.

[0087] In this specification, "electron-accepting monomer" refers to a monomer having an electron-withdrawing group on the carbon-carbon double bond that participates in the polymerization reaction.

[0088] In the present specification, unless otherwise specifically stated, "alkyl" means both straight-chain and branched-chain alkyl groups.

[0089] In this specification, the "reaction system" refers to a system consisting of an electron-accepting monomer, a Fischer-Tropsch synthesis product, a polar monomer, an initiator, and a solvent.

[0090] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0091] In this specification, unless otherwise specified, "%" means mass or weight percentage.

[0092] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0093] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0094] In this specification, "optionally" or "optional" is used to indicate that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0095] In this specification, the unit names used are all international standard unit names, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0096] In this specification, references to "preferred embodiments," "embodiments," and the like mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in any suitable manner in the various embodiments.

[0097] Self-stabilizing precipitation polymerization method

[0098] An object of the present invention is to provide a self-stabilizing precipitation polymerization method, characterized in that it comprises the following steps:

[0099] subjecting a reaction system comprising a Fischer-Tropsch synthesis product, an electron-accepting monomer, a polar monomer, an initiator, and a solvent to self-stabilizing precipitation polymerization;

[0100] The polar monomer is at least one selected from vinyl acetate, glycidyl methacrylate, and methyl methacrylate;

[0101] The Fischer-Tropsch synthesis product comprises α-olefins.

[0102] The reaction system of the self-stabilizing precipitation polymerization method of the present invention comprises a Fischer-Tropsch synthesis product, an electron-accepting monomer, a polar monomer, an initiator and a solvent.

[0103] The method of the present invention introduces a specific polar monomer as a third monomer into the reaction system, thereby allowing the Fischer-Tropsch synthesis product to be directly converted into copolymer microspheres with controllable particle size, uniform distribution, and functional groups through a self-stabilizing precipitation polymerization method. The method of the present invention does not require any separation or purification of the Fischer-Tropsch synthesis product, the polymerization method is simple, the reaction conditions are mild, and after the reaction is completed, the copolymer microspheres can be obtained through simple steps such as solid-liquid separation and drying. The supernatant after solid-liquid separation can be recycled, and the unreacted α-olefins and alkanes that do not participate in the reaction can also be recovered, which has the characteristics of green polymerization. The method of the present invention provides a new way to high-value resource utilization of Fischer-Tropsch synthesis products.

[0104] Each aspect of the self-stabilizing precipitation polymerization of the present invention is described in detail below.

[0105] <Polar Monomer>

[0106] In the present invention, the polar monomer is at least one selected from vinyl acetate, glycidyl methacrylate, and methyl methacrylate.

[0107] The present invention introduces a specific polar monomer with similar polymerization activity to that of α-olefins into the reaction system to increase the cohesive energy density of the copolymer, thereby allowing the α-olefins in the Fischer-Tropsch synthesis product to directly undergo self-stabilizing precipitation polymerization, and directly converting the mixed α-olefin fraction in the Fischer-Tropsch synthesis product that is not easily homopolymerized by free radicals into functionalized high-value polymer microspheres, while ensuring a high precipitation yield and a high α-olefin conversion rate.

[0108] In addition to achieving self-stabilizing precipitation polymerization, the use of polar monomers can also introduce functional groups into the copolymer. Depending on the polar monomer, the functional groups can be, for example, epoxy groups, carboxylate groups, etc.

[0109] <Fischer-Tropsch synthesis products>

[0110] Fischer-Tropsch synthesis products are the products of Fischer-Tropsch synthesis technology. Their components include normal alkanes, normal olefins, branched alkanes, branched olefins and normal alcohols, among which normal alkanes and normal olefins are the main components, and the olefin components are mostly α-olefins.

[0111] The composition of the Fischer-Tropsch synthesis product is not particularly limited in the present invention, as long as it includes an α-olefin capable of copolymerizing with an electron-donating monomer and an electron-accepting monomer. Persons skilled in the art can select the composition as needed. The Fischer-Tropsch synthesis product can be an unfractionated Fischer-Tropsch synthesis oil, different fractions of the Fischer-Tropsch synthesis oil, or a Fischer-Tropsch synthesis wax, as long as it contains α-olefins.

[0112] Preferably, the mass content of α-olefins in the Fischer-Tropsch synthesis product is 1-70%, preferably 5-65%, more preferably 20-65%, such as 30%, 40%, 50%, 60%, etc.

[0113] Preferably, the α-olefin is one or a combination of two or more selected from α-olefins having 4 to 40 carbon atoms, preferably selected from 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentacosene, 1-hexacosene, 1-heptacosene, 1-octacosene, 1-nonacosene, 1-triacont ...

[0114] In one embodiment, the Fischer-Tropsch synthesis product is a Fischer-Tropsch synthesis oil and / or a Fischer-Tropsch synthesis wax, wherein the Fischer-Tropsch synthesis oil is preferably a Fischer-Tropsch synthesis oil washed naphtha and / or a Fischer-Tropsch synthesis stable heavy oil. The Fischer-Tropsch synthesis oil washed naphtha mainly contains components from C4 to C14, of which about 60 to 70% are α-olefins. The Fischer-Tropsch synthesis stable heavy oil mainly contains components from C8 to C30, of which about 55 to 65% are α-olefins. The Fischer-Tropsch synthesis heavy wax mainly contains components with higher carbon numbers (above C30), of which about 1 to 10% are α-olefins.

[0115] The inventors have discovered that components other than α-olefins in the Fischer-Tropsch synthesis product, such as normal alkanes, branched alkanes, and other components, can serve as the medium (solvent) in the reaction system. These media can also be separated after polymerization and used as products such as gasoline and diesel.

[0116] <Electron-accepting monomer>

[0117] In the present invention, an electron-accepting monomer is used to polymerize with the α-olefin in the Fischer-Tropsch synthesis product to obtain a functional copolymer having functional groups. The electron-accepting monomer can also introduce functional groups, such as anhydride groups and imide groups, into the copolymer.

[0118] In one embodiment, the electron-accepting monomer is one or a combination of two or more selected from maleic anhydride, maleimide, itaconic anhydride, and derivatives thereof. Here, a derivative refers to a compound obtained by replacing the hydrogen atoms on carbon atoms or nitrogen atoms of maleic anhydride, maleimide, or itaconic anhydride with other groups (e.g., alkyl groups, aromatic hydrocarbon groups, halogen atoms, etc.).

[0119] Preferably, the electron-accepting monomer is one or a combination of two or more selected from maleic anhydride, itaconic anhydride, maleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, and N-(1-naphthyl)maleimide.

[0120] <Monomer Composition>

[0121] In one embodiment, the total mass concentration of the α-olefin, the electron-accepting monomer, and the polar monomer in the reaction system (hereinafter also referred to as the "total monomer concentration") is 10 to 70% by mass, preferably 20 to 60% by mass, for example, 25% by mass, 30% by mass, 35% by mass, 40% by mass, 45% by mass, 50% by mass, 55% by mass, etc. By adjusting the total monomer concentration within this range, the polymerization reaction can proceed better.

[0122] In one embodiment, the mass ratio of the electron-accepting monomer to the Fischer-Tropsch synthesis product is 1:30 to 5:1, preferably 1:8 to 2:1, for example: 1:25, 1:20, 1:15, 1:10, 1:5, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, etc.

[0123] In one embodiment, based on the total mass of α-olefin, electron-accepting monomer and polar monomer as 100%, the mass fraction of polar monomer is 14-40% by mass, preferably 23-35% by mass, for example, 20%, 22%, 25%, 27%, 30%, 33%, 37%, etc.

[0124] <Initiator>

[0125] In the present invention, an electron-accepting monomer, a polar monomer, and an α-olefin in the Fischer-Tropsch synthesis product are polymerized using an initiator. In one embodiment, the initiator is one or more selected from azo compound initiators and peroxide initiators. Preferably, the peroxide initiator is dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, or dicyclohexyl peroxydicarbonate; and the azo compound initiator is azobisisobutyronitrile or azobisisoheptonitrile.

[0126] In one embodiment, based on the total weight of the α-olefin, the electron-accepting monomer, and the polar monomer as 100%, the content of the initiator is 0.05 to 10 wt%, preferably 0.5 to 5 wt%, and more preferably 1 to 5 wt%. For example, 0.1 wt%, 0.5 wt%, 1 wt%, 2.5 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 7 wt%, 9 wt%, etc. When the initiator content is 0.05 to 10 wt%, the desired copolymer can be obtained.

[0127] <Solvent>

[0128] The present invention does not particularly limit the solvent, and can be a commonly used solvent in the art. Specifically, the solvent is an organic solvent, preferably, the organic solvent includes one or a combination of two or more selected from hydrocarbon solvents, ketone solvents, carboxylic acid ester solvents and ether solvents.

[0129] The carboxylate compound may have a structure as shown in the following formula (I):

[0130]

[0131] In formula (I), R4 is a hydrogen atom, a C1-C6 alkyl group or a C6-C10 aryl group, and R5 is a C1-C8 alkyl group or a C6-C10 aryl group; specifically, the C6-C10 aryl group can be a phenyl group, a benzyl group, a phenethyl group, or the like.

[0132] Specific examples of the carboxylic acid ester compound may be ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, ethyl isobutyrate, ethyl isovalerate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, ethyl phenylacetate, propyl phenylacetate, butyl phenylacetate, isoamyl phenylacetate, and the like, or an ester solvent selected from the group consisting of one or a combination of two or more thereof.

[0133] The ketone compound can be selected from one or a combination of two or more of acetone, butanone, cyclohexanone, methyl isobutyl ketone, methyl isopropyl ketone, etc.

[0134] The ether solvent can be selected from one or a combination of two or more of dimethyl ether, methyl ethyl ether, ethyl ether, ethyl propyl ether, dipropyl ether, dibutyl ether, methyl propyl ether, methyl butyl ether, methyl isobutyl ether, methyl tert-butyl ether, methyl isopentyl ether, methyl tert-amyl ether, methyl cyclopentyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, etc.

[0135] The hydrocarbon solvent may be at least one selected from an alkane solvent and an aromatic hydrocarbon solvent, and is preferably one or a combination of two or more selected from n-hexane, cyclohexane, benzene, toluene, and xylene.

[0136] Preferably, the solvent includes at least one ether solvent, preferably selected from the ether solvents described above. Because a low-boiling-point ether solvent is used, the copolymer obtained by solid-liquid separation contains less solvent entrapped, resulting in a clean surface for the polymer microspheres. Preferably, the total content of the ether solvent in the solvent is 80% by mass or greater, preferably 90% by mass or greater, for example 95% by mass, or even 100% by mass.

[0137] The present invention does not impose any particular limitation on the amount of solvent used, and it can be added as needed, as long as the electron-accepting monomer, Fischer-Tropsch synthesis product, polar monomer, and initiator can be fully dissolved and the polymerization product is insoluble in the solvent.

[0138] Preferably, the mass ratio of the solvent to the electron-accepting monomer is (10-0.1):1, preferably (9-0.2):1, for example, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 0.8:1, 0.5:1, etc.

[0139] Preferably, the solubility parameter of the copolymer as the polymerization product is 1 to 7 MPa greater than the solubility parameter of the organic solvent by selecting the solvent. 1 / 2 , preferably 2~5MPa 1 / 2 .

[0140] The solubility parameter of a polymer has the usual meaning in the art and can be calculated using the indirect method, i.e., the contribution of each group in the molecular structure, as follows:

[0141] δ=ρ∑F i / M

[0142] Where, δ is the solubility parameter of the polymer; F i is the molar attraction constant of each group component in the polymer molecule; ρ is the density of the polymer; M is the chain molecular weight of the polymer.

[0143] For the solubility parameters of solvents, those skilled in the art can find them in technical manuals or public literature in this field. For example, the solubility parameters of various solvents are recorded in "Polymer Physics" (Hua Youqing, Jin Riguang, Chemical Industry Press, 2013, page 83).

[0144] <Polymerization Process>

[0145] In the present invention, there is no particular limitation on the order and method of mixing the components in the reaction system, and the components can be mixed in any appropriate manner and order.

[0146] Preferably, after the electron-accepting monomer, initiator and solvent are mixed, the Fischer-Tropsch synthesis product and polar monomer are added, so that the resulting reaction system undergoes self-stabilizing precipitation polymerization.

[0147] In some specific embodiments, the polymerization reaction is initiated by heating the reaction system to a polymerization reaction temperature, which can be 50-120° C., preferably 60-110° C., for example, 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., 90° C., 95° C., 100° C., 105° C., 110° C., 115° C., etc.

[0148] Preferably, the polymerization reaction time is 1 to 24 hours, for example, 2 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, etc.

[0149] Preferably, the polymerization reaction can be carried out under the protection of an inert gas. Specifically, the inert gas can be nitrogen or argon.

[0150] Based on the characteristics of the self-stabilizing precipitation polymerization reaction method itself, the reaction medium (solvent) has a good dissolving effect on the electron-accepting monomer, initiator and Fischer-Tropsch synthesis product, and is miscible with the polar monomer to ensure that it is a homogeneous system before the reaction. However, the reaction medium cannot dissolve the generated copolymer. When the polymer molecular chain reaches a certain critical length, it precipitates out of the reaction medium. However, the precipitated polymer cannot precipitate in the form of powder or lump as in precipitation polymerization, but is stably suspended in the reaction medium in the form of microspheres or particles, forming a stable dispersion system similar to a polymer emulsion.

[0151] <Post-processing>

[0152] In a specific embodiment, the self-stabilizing precipitation polymerization method of the present invention further comprises a step of post-treating the reaction system after the self-stabilizing precipitation polymerization, wherein the post-treatment preferably comprises one or a combination of two or more of solid-liquid separation, washing or drying.

[0153] Based on the characteristics of the self-stabilizing precipitation polymerization method itself, the reaction system obtained after polymerization is a dispersed system of copolymer microspheres. Therefore, there is no need to use a precipitant, and the copolymer microspheres can be separated only by solid-liquid separation.

[0154] More specifically, after the polymerization reaction, the reaction system is subjected to solid-liquid separation, and the separated solid (copolymer microspheres) is optionally dried.

[0155] Solid-liquid separation can be carried out by known methods, such as filtration, centrifugation, solvent evaporation and the like.

[0156] The washing can be performed by rinsing the separated solid with a washing solvent, dispersing the separated solid in a washing solvent and then performing solid-liquid separation again, etc. The washing solvent is preferably the solvent used in the reaction.

[0157] Drying can be carried out by methods known in the art, such as heating to evaporate the residual solvent. The drying temperature can be 40 to 150° C., such as 40 to 100° C., and the drying time can be 1 to 48 hours, such as 4 to 40 hours or 8 to 30 hours.

[0158] Copolymer

[0159] The present invention also relates to a copolymer (microsphere) obtained by the method of the present invention, which is a terpolymer of α-olefin, electron-accepting monomer and polar monomer. The copolymer of the present invention has a high content of functional groups.

[0160] The average particle size of the copolymer microspheres of the present invention is 0.1-10 μm, preferably 0.2-8 μm, more preferably 0.3-5 μm, further preferably 0.4-3 μm, and the particle size distribution coefficient is 1.001-1.2, preferably 1.002-1.15, more preferably 1.003-1.1, for example 1.004-1.06.

[0161] In the copolymer microspheres of the present invention, the content of residual solvent is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less, and even 1% by mass or less.

[0162] In one embodiment, the copolymer of the present invention may have a number average molecular weight of 1,000 to 100,000, for example, 1,500 to 10,000, as measured by gel permeation chromatography.

[0163] Example

[0164] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0165] The composition of the Fischer-Tropsch oil-washed naphtha (also referred to as "oil-washed naphtha") used in the following examples is shown in Table 1 below:

[0166] Table 1

[0167]

[0168] The composition of the Fischer-Tropsch stable heavy oil (also referred to as "stable heavy oil") used in the following examples is shown in Table 2 below:

[0169] Table 2

[0170]

[0171] The composition of the Fischer-Tropsch wax used in the following examples (average carbon number is 22.13) is shown in Table 3 below:

[0172] Table 3

[0173] type content α-olefins 10.53％ Internal olefins 13.19％ normal alkanes 76.28％

[0174] In the following examples, the post-treatment after the polymerization reaction was performed as follows:

[0175] The polymerization reaction system was centrifuged at 7000 rpm for 5 minutes to obtain a precipitate and a supernatant. The precipitate was washed with the solvent used in the polymerization reaction and centrifuged three times. The supernatant was added to petroleum ether for precipitation to obtain a small amount of precipitate product. This was then centrifuged, washed with petroleum ether, and centrifuged three times to obtain a supernatant product. Both the precipitate and supernatant products were vacuum dried to constant weight to obtain two copolymer products. The supernatant yield and total yield described below were calculated based on the weights of the two copolymer products obtained.

[0176] Example 1

[0177] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in 1.68 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.97 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 13%, and the total yield was 85%.

[0178] Comparative Example 1

[0179] 0.61g of maleic anhydride and 0.052g of dibenzoyl peroxide were dissolved in 1.22g of methyl tert-butyl ether (MTBE) solvent, sonicated, and mixed to obtain a transparent solution. 0.70g of Fischer-Tropsch stabilized heavy oil was then added, nitrogen was purged through the system for 10 minutes, and the reaction was maintained at 80°C for 8 hours to obtain a homogeneous solution polymerization system. The reaction solution was added to petroleum ether for precipitation to obtain a precipitated product. The precipitated product was centrifuged at 7000 rpm for 5 minutes, washed with petroleum ether, and centrifuged three times. Finally, the product was vacuum dried to constant weight to obtain 0.67g of a Fischer-Tropsch stabilized heavy oil-maleic anhydride copolymer with a yield of 65%.

[0180] Example 2

[0181] 0.67 g of maleic anhydride and 0.069 g of dibenzoyl peroxide were dissolved in 1.85 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.39 g of Fischer-Tropsch stable heavy oil and 0.47 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 1.21 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 6%, and the total yield was 94%.

[0182] Example 3

[0183] 0.58 g of maleic anhydride and 0.068 g of dibenzoyl peroxide were dissolved in 1.64 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.85 g of Fischer-Tropsch stable heavy oil and 0.26 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.83 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 19%, and the total yield was 80%.

[0184] Example 4

[0185] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in 5.04 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.82 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 10%, and the total yield was 71%.

[0186] Example 5

[0187] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in 0.56 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 1.05 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 14%, and the total yield was 92%.

[0188] Example 6

[0189] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in a mixed solvent of 1.01 g of isoamyl acetate and 0.67 g of n-hexane, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes, and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.87 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 30%, and the total yield was 95%.

[0190] Example 7

[0191] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in a mixed solvent of 0.34 g of butanone and 1.34 g of cyclohexane, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes, and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.93 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 22%, and the total yield was 91%.

[0192] Example 8

[0193] 0.61 g of maleic anhydride and 0.067 g of dibenzoyl peroxide were dissolved in a mixed solvent of 1.68 g of xylene, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes, and the system was kept at a constant temperature of 80°C for 8 hours to obtain a dispersed system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.96 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 16%, and the total yield was 88%.

[0194] Example 9

[0195] 0.61 g of maleic anhydride and 0.067 g of azobisisobutyronitrile were dissolved in 1.68 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at a constant temperature of 70°C for 8 hours to obtain a dispersed system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.99 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 19%, and the total yield was 93%.

[0196] Example 10

[0197] 0.57 g of maleic anhydride and 0.054 g of dibenzoyl peroxide were dissolved in 1.43 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.40 g of Fischer-Tropsch synthetic oil-washed naphtha and 0.26 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum-dried at 80°C for 24 hours to constant weight to obtain 0.86 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 2%, and the total yield was 78%.

[0198] Comparative Example 2

[0199] 0.57g of maleic anhydride and 0.054g of dibenzoyl peroxide were dissolved in 1.05g of methyl tert-butyl ether (MTBE) solvent, sonicated, and mixed to obtain a transparent solution. 0.40g of Fischer-Tropsch oil-washed naphtha was then added, nitrogen was purged through the system for 10 minutes, and the mixture was kept at 80°C for 8 hours, resulting in a layered system consisting of a hard precipitate and a supernatant. The hard precipitate was removed and dried to constant weight, yielding 0.48g of Fischer-Tropsch oil-washed naphtha-maleic anhydride copolymer, representing a precipitate yield of 58%. The supernatant was then added to petroleum ether for precipitation, yielding a small amount of supernatant precipitate. The precipitate was centrifuged at 7000 rpm for 5 minutes, washed with petroleum ether, centrifuged three times, and dried under vacuum to constant weight, yielding 0.05g of Fischer-Tropsch oil-washed naphtha-maleic anhydride copolymer, representing a supernatant yield of 6% and a total yield of 64%.

[0200] Example 11

[0201] 0.57 g of maleic anhydride and 0.054 g of dibenzoyl peroxide were dissolved in a mixed solvent of 0.86 g of isoamyl acetate and 0.57 g of n-hexane, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.40 g of Fischer-Tropsch oil-washed naphtha and 0.26 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes, and the system was kept at 80° C. for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum-dried at 80° C. for 24 hours to constant weight to obtain 0.66 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 15%, and the total yield was 73%.

[0202] Example 12

[0203] 0.77 g of itaconic anhydride and 0.079 g of dibenzoyl peroxide were dissolved in 2.02 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.38 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of itaconic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.81 g of itaconic anhydride, vinyl acetate and α-olefin copolymer microspheres as a white solid powder. The yield in the supernatant was 16%, and the total yield was 67%.

[0204] Example 13

[0205] 0.60 g of maleimide and 0.067 g of dibenzoyl peroxide were dissolved in 1.68 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.32 g of vinyl acetate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleimide, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.67 g of maleimide, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 21%, and the total yield was 71%.

[0206] Example 14

[0207] 0.43 g of maleic anhydride and 0.056 g of dibenzoyl peroxide were dissolved in 1.36 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch synthesis stable heavy oil and 0.27 g of glycidyl methacrylate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at a constant temperature of 80°C for 8 hours to obtain a dispersion system of maleic anhydride, glycidyl methacrylate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.58 g of maleic anhydride, glycidyl methacrylate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 8%, and the total yield was 60%.

[0208] Example 15

[0209] 0.53 g of maleic anhydride and 0.063 g of dibenzoyl peroxide were dissolved in 1.55 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.70 g of Fischer-Tropsch stable heavy oil and 0.31 g of methyl methacrylate were added. Nitrogen was passed through the system for 10 minutes and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, methyl methacrylate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.52 g of maleic anhydride, methyl methacrylate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 20%, and the total yield was 61%.

[0210] Comparative Example 3

[0211] 0.61g of maleic anhydride and 0.067g of dibenzoyl peroxide were dissolved in 1.68g of methyl tert-butyl ether solvent, sonicated, and mixed to obtain a transparent solution. 0.70g of Fischer-Tropsch stabilized heavy oil and 0.32g of methyl acrylate were then added. Nitrogen was purged through the system for 10 minutes, and the reaction was maintained at 80°C for 8 hours, resulting in a layered system consisting of a hard precipitate and a supernatant. The hard precipitate was removed and dried to constant weight, yielding 0.52g of a terpolymer of maleic anhydride, methyl acrylate, and α-olefin, representing a precipitate yield of 39%. The supernatant was then added to petroleum ether for precipitation, yielding a small amount of supernatant precipitate. The precipitate was centrifuged at 7000 rpm for 5 minutes, washed with petroleum ether, centrifuged three times, and dried under vacuum to a constant weight, yielding 0.47g of the terpolymer, representing a supernatant yield of 35% and a total yield of 74%.

[0212] Comparative Example 4

[0213] 0.49g of maleic anhydride and 0.061g of dibenzoyl peroxide were dissolved in 1.49g of methyl tert-butyl ether solvent, sonicated, and mixed to obtain a transparent solution. 0.70g of Fischer-Tropsch stabilized heavy oil and 0.29g of ethyl methacrylate were then added. Nitrogen was purged through the system for 10 minutes, and the reaction was maintained at 80°C for 8 hours, resulting in a layered system consisting of a hard precipitate and a supernatant. The hard precipitate was removed and dried to constant weight, yielding 0.47g of a terpolymer of maleic anhydride, ethyl methacrylate, and α-olefin, representing a precipitate yield of 38%. The supernatant was then added to petroleum ether for precipitation, yielding a small amount of supernatant precipitate. The precipitate was centrifuged at 7000 rpm for 5 minutes, washed with petroleum ether, centrifuged three times, and dried under vacuum to constant weight, yielding 0.43g of the terpolymer, representing a supernatant yield of 36% and a total yield of 74%.

[0214] Comparative Example 5

[0215] 0.43g of maleic anhydride and 0.057g of dibenzoyl peroxide were dissolved in 1.36g of methyl tert-butyl ether (MTBE) solvent and sonicated to dissolve and mix thoroughly to obtain a transparent solution. 0.70g of Fischer-Tropsch stabilized heavy oil and 0.27g of n-butyl methacrylate were then added. Nitrogen was purged through the system for 10 minutes and the reaction was maintained at 80°C for 8 hours to obtain a homogeneous solution polymerization system. The reaction solution was added to petroleum ether for precipitation to obtain a precipitated product. The precipitated product was centrifuged at 7000 rpm for 5 minutes, washed with petroleum ether, and centrifuged three times. Finally, the product was vacuum dried to constant weight to obtain 0.74g of a terpolymer of maleic anhydride, n-butyl methacrylate, and α-olefin in a yield of 66%.

[0216] Example 16

[0217] 4.0 g of Fischer-Tropsch wax, 0.56 g of maleic anhydride and 0.063 g of dibenzoyl peroxide were dissolved in 0.11 g of methyl tert-butyl ether solvent, dissolved and mixed uniformly by ultrasonication to obtain a transparent solution, and then 0.29 g of vinyl acetate was added. Nitrogen was passed through the system for 10 minutes, and the system was kept at 80°C for 8 hours to obtain a dispersion system of maleic anhydride, vinyl acetate and α-olefin terpolymer microspheres. The system was then centrifuged and vacuum dried at 80°C for 24 hours to constant weight to obtain 0.23 g of maleic anhydride, vinyl acetate and α-olefin copolymer microspheres in the form of a white solid powder. The yield in the supernatant was 10%, and the total yield was 28%.

[0218] <Testing and Evaluation>

[0219] SEM analysis

[0220] Use a toothpick to take a small amount of dried copolymer solid powder and evenly apply it on the conductive glue. Use an ear bulb to blow away the unadhered powder to ensure that the powder is distributed in a single layer. After gold spraying, the morphology of the copolymer is observed using a field emission scanning electron microscope (produced by JEOL, model: JSM7401) to obtain SEM photos. The SEM photos of the copolymer microspheres of Examples 1, 2, 3, 10, 14 and 15 are shown respectively. Figures 1 to 6 As shown; SEM photos of the copolymers of the lower precipitates of Comparative Examples 2 to 4 are as follows Figures 7-9 shown.

[0221] Figures 1 to 6 The results show that the product obtained by the polymerization of specific polar monomers in the present invention is microspheres with uniform particle size distribution, and the particle size and distribution of the microspheres can be controlled by changing the amount of polar monomer added. Figures 7-9 This indicates that self-stabilizing precipitation polymerization cannot be performed using polar monomers that do not conform to the present invention, and polymer microspheres cannot be obtained.

[0222] Particle size analysis

[0223] The particle size and distribution data of copolymer microspheres were obtained by the following method:

[0224] First, the particle size and particle size distribution of the microspheres in the scanning electron microscope photograph are measured using measurement statistics software, and the particle size and distribution of the measured microspheres can be calculated using formulas (1)-(3).

[0225]

[0226] U=D w / D n Formula (3)

[0227] in:

[0228] Dn ——Number average particle size of polymer microspheres;

[0229] D w ——Weight average particle size of polymer microspheres:

[0230] D i ——the particle size of the i-th microsphere;

[0231] N——total number of microspheres;

[0232] U - dispersion coefficient of microsphere particle size.

[0233] The particle size and distribution data of the copolymer microspheres obtained in Examples 1 to 16 are shown in Table 4. As shown in Table 4, the particle size of the copolymer microspheres obtained in Examples 1 to 16 is 0.7 to 2.5 μm, the particle size distribution coefficient is small, and the particle size uniformity is high.

[0234] NMR carbon spectrum ( 13 C-NMR)

[0235] The copolymer solid powder obtained in Example 1 was dissolved in CD3CN solvent and heated at room temperature. 13 C-NMR test, such as Figure 10 The test results show the presence of alkyl carbon atoms (13 ppm, 22-37 ppm), anhydride carbon atoms (40 ppm, 49 ppm), and ester carbon atoms (20 ppm, 68 ppm) in the copolymer. This indicates that α-olefin, maleic anhydride, and vinyl acetate are incorporated into the copolymer.

[0236] DSC analysis

[0237] 10 mg of the copolymer solid powder obtained in Example 1 and Example 10 were weighed into a crucible and placed in the sample position of the instrument for measurement. After eliminating the thermal history, the temperature was raised from 30°C to 200°C at a rate of 10°C / min. During this process, the glass transition temperature (Tg) of the copolymer was observed. Figure 11 As shown in Figure 2, both the naphtha copolymer and the heavy oil copolymer have only one glass transition temperature. This indicates that the resulting copolymer is a terpolymer rather than a mixture of two copolymers.

[0238] Molecular weight test

[0239] Using tetrahydrofuran as eluent, a copolymer sample solution with a concentration of 5 mg / mL was accurately prepared, and the molecular weight of the copolymer was measured using gel permeation chromatography. The various properties and evaluation results of the copolymer microspheres obtained in Examples 1 to 16 and Comparative Examples 1 to 5 are shown in Table 4.

[0240] As shown in Table 4, the number average molecular weight of the copolymer is about 2200-4700 g / mol. The molecular weight can be adjusted by changing the amount of polar monomer added, the total monomer concentration, the reaction solvent, the Fischer-Tropsch synthesis product and the type of polar monomer.

[0241] Table 4

[0242]

[0243] Industrial applicability

[0244] The method of the present invention can be widely used in industry to prepare functional copolymer microspheres.

Claims

1. A self-stabilizing precipitation polymerization method, characterized in that: The following steps are involved: subjecting a reaction system comprising a Fischer-Tropsch synthesis product, an electron-accepting monomer, a polar monomer, an initiator, and a solvent to self-stabilizing precipitation polymerization; The polar monomer is at least one selected from vinyl acetate, glycidyl methacrylate, and methyl methacrylate; The Fischer-Tropsch synthesis product comprises α-olefins.

2. The self-stabilizing precipitation polymerization method according to claim 1, characterized in that The electron-accepting monomer is one or a combination of two or more selected from maleic anhydride, maleimide, itaconic anhydride and their derivatives; The Fischer-Tropsch synthesis product is Fischer-Tropsch synthesis oil and / or Fischer-Tropsch synthesis wax; The initiator is one or more selected from azo compound initiators and peroxide initiators; The solvent is an organic solvent.

3. The self-stabilizing precipitation polymerization method according to claim 2, characterized in that The electron-accepting monomer is selected from maleic anhydride, itaconic anhydride, maleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-(1-naphthyl)maleimide, or a combination of two or more thereof; The Fischer-Tropsch synthetic oil is Fischer-Tropsch synthetic oil-washed naphtha and / or Fischer-Tropsch synthetic stable heavy oil; the content of α-olefin in the Fischer-Tropsch synthetic product is 1 to 70% by mass; The solvent is one or a combination of two or more selected from hydrocarbon solvents, ketone solvents, carboxylic acid ester solvents and ether solvents; The azo compound initiator is azobisisobutyronitrile or azobisisoheptanenitrile; The peroxide initiator is dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, or dicyclohexyl peroxydicarbonate.

4. The self-stabilizing precipitation polymerization method according to any one of claims 1 to 3, characterized in that The solvent is one or more selected from amyl acetate, isoamyl acetate, acetone, butanone, methyl butyl ether, methyl isobutyl ether, methyl tert-butyl ether, methyl isoamyl ether, methyl tert-amyl ether, n-hexane, cyclohexane, toluene, and xylene.

5. The self-stabilizing precipitation polymerization method according to any one of claims 1 to 3, characterized in that In the reaction system, the total mass concentration of α-olefin, electron-accepting monomer and polar monomer is 10 to 70% by mass, preferably 20 to 60% by mass; Based on the total mass of the α-olefin, the electron-accepting monomer and the polar monomer as 100%, the mass fraction of the polar monomer is 14 to 40 mass%, preferably 23 to 35 mass%; The mass ratio of the electron-accepting monomer to the Fischer-Tropsch synthesis product is 1:30 to 5:1, preferably 1:8 to 2:1; Based on the total mass of the α-olefin, the electron-accepting monomer and the polar monomer as 100%, the amount of the initiator is 0.05 to 10% by mass, preferably 1 to 5% by mass.

6. The self-stabilizing precipitation polymerization method according to any one of claims 1 to 3, characterized in that After the electron-accepting monomer, initiator and solvent are mixed, the Fischer-Tropsch synthesis product and polar monomer are added, so that the obtained reaction system undergoes self-stabilizing precipitation polymerization.

7. The self-stabilizing precipitation polymerization method according to any one of claims 1 to 3, characterized in that The self-stabilizing precipitation polymerization is carried out in an inert gas, the polymerization reaction temperature is 50 to 120° C., and the polymerization reaction time is 1 to 24 hours.

8. The self-stabilizing precipitation polymerization method according to any one of claims 1 to 3, characterized in that The method further comprises a step of post-treating the reaction system after the self-stabilizing precipitation polymerization, wherein the post-treatment preferably comprises one or a combination of two or more of solid-liquid separation, washing or drying.

9. A copolymer obtained by the self-stabilizing precipitation polymerization method according to any one of claims 1 to 8.

10. The copolymer according to claim 9, characterized in that The copolymer is copolymer microspheres with a number average particle size of 0.1 to 10 μm and a particle size distribution coefficient of 1.001 to 1.2.

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