CN116789881A

CN116789881A - Method for synthesizing olefin functional polymer by plasma initiation

Info

Publication number: CN116789881A
Application number: CN202310759156.7A
Authority: CN
Inventors: 张留乔; 丁克鸿; 王根林; 王铖; 冯青宇; 史青
Original assignee: Jiangsu Yangnong Chemical Group Co Ltd
Current assignee: Jiangsu Yangnong Chemical Group Co Ltd
Priority date: 2023-06-26
Filing date: 2023-06-26
Publication date: 2023-09-22

Abstract

The invention provides a method for synthesizing an olefin functional polymer by plasma initiation, which comprises the following steps: introducing low-carbon olefin into a reactor, raising the temperature and the pressure, adding raw material liquid prepared from functional monomers and a solvent into the reactor, introducing plasma into the reactor, and performing polymerization reaction; and (3) carrying out gas-solid-liquid separation on the materials after the polymerization reaction, recovering the low-carbon olefin, and carrying out solid-liquid separation on the rest materials to obtain the solid-phase olefin functional polymer and the liquid-phase material. The invention realizes the same-chain alternate copolymerization of the low-carbon gaseous olefin and the functional monomer through the pressurized reaction of the low-carbon gaseous olefin and the functional monomer, and adopts a heterogeneous polymerization mode to improve the monomer concentration and the raw material utilization rate; the invention adopts plasma to initiate polymerization, so that the polymer is purer and easy to prepare the polymer with high molecular weight; the method is simple to operate, mild in reaction condition, easy to separate and purify, energy-saving and environment-friendly.

Description

Method for synthesizing olefin functional polymer by plasma initiation

Technical Field

The invention belongs to the technical field of organic polymerization, and relates to a method for synthesizing an olefin functional polymer by plasma initiation.

Background

The olefin functional polymer is used as a functional high polymer material, has wide application in the aspects of engineering plastic chain extension, high-performance composite material, nylon infiltration, ink dispersion, microencapsulation, filtration membrane film formation and the like, and is greatly concerned. The molecular chain of the olefin functional polymer has a large number of active groups, and can react with various functional groups, such as hydroxyl-terminated or amino-terminated nylon products, so that the molecular weight of nylon is improved, the mechanical property is improved, and the viscosity value of nylon is regulated; in addition, the olefin functional polymer can be used for preparing microcapsules, and has good application prospects in the fields of pesticides, fragrances and medicines.

The synthetic raw materials of the olefin functional polymer mainly comprise olefin and functional monomers, and currently available polymerization methods comprise emulsion polymerization, suspension polymerization and precipitation polymerization, wherein a large amount of stabilizer is needed to be used in the former two methods, and the stabilizer is remained on polymer particles in a physical adsorption or chemical adsorption mode to influence the performance of the polymer particles; although the precipitation polymerization does not need to add a stabilizer, the concentration of a polymerization monomer in the traditional precipitation polymerization system is low, so that the polymerization efficiency is low, and the polymerization method needs to be improved; since the synthesis of polymers generally requires initiation of free radicals generated by the initiation reaction, the initiation means include photoinitiation, thermal initiation, initiator initiation, etc., initiator initiation is most commonly employed at present. In recent years, plasma initiation technology has also been attracting attention based on the characteristics of high-energy particles, and the study of polymerization initiated by plasma has been increasing, possibly being more advantageous in some reactions.

Depending on the kind of olefin or functional monomer in the kind of olefin functional polymer synthesis raw material, a corresponding synthesis process is required. CN 101235117a discloses a method for styrene/maleic anhydride copolymerization, which comprises dissolving maleic anhydride monomer, styrene, initiator organic peroxide or azo compound in medium under nitrogen protection, reacting with 60-90 deg.c for 0.25-12 h to obtain dispersion system of polymer microsphere. CN 102212166a discloses a new method for copolymerization of dicyclopentadiene and maleic anhydride, which is to add monomer and initiator into organic medium to dissolve under nitrogen protection, react for 2-12 h at 60-90 deg.c to obtain self-stable dispersion system of monodisperse microsphere of alternating copolymer, and then centrifugally separate and dry to obtain white solid of alternating copolymer of dicyclopentadiene/maleic anhydride. In the above patents, maleic anhydride is used as a functional monomer to polymerize with an olefin, but the olefin used is usually an olefin of at least C4, and is usually a liquid olefin such as a diene, a cycloolefin or an isoolefin, but the polymerization of a gaseous olefin of at most C4 is not involved, and an initiator is used to initiate the reaction.

The plasma initiated polymerization was first carried out in laboratory by Bell. A.T et al, and a series of vinyl monomers such as an aqueous alkene solution, an aqueous acrylic acid solution, methyl methacrylate, etc. were successfully polymerized, because the initiated polymerization is mainly based on free radicals generated by the interaction of plasma and monomers, and no external free radical initiator is added, the polymer is purer, and the molecular weight of the polymer is more than 10, which is characterized in that ⁷ The advent of this method has led to tremendous research enthusiasm.

CN 101531730a discloses a method for preparing styrene-maleic anhydride copolymer by plasma initiation, which comprises ionizing air into plasma under normal pressure, introducing the plasma into acetone solution of styrene monomer and maleic anhydride for polymerization, wherein the air flow is 20-80 ml/min, the discharge time is 10-30 min, adding absolute ethanol precipitant after polymerization for 1-2 h to terminate the reaction, repeatedly washing with absolute ethanol, and vacuum drying to obtain copolymer; although the reaction is initiated by plasma, the polymerization of liquid olefins is still not involved in the polymerization of C4 or less gaseous olefins with functional monomers.

In summary, for the synthesis of olefin functional polymers, especially the polymerization of lower olefins with carbon numbers below C4 and functional monomers, a proper initiation mode and synthesis process are also required to be selected according to the characteristics of the raw materials, so as to improve the production efficiency, simplify the separation process, and reduce the raw materials and process costs.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention aims to provide a method for synthesizing an olefin functional polymer by plasma initiation, which realizes the same-chain alternate copolymerization of low-carbon gaseous olefin and functional monomer by the pressurized reaction of the low-carbon gaseous olefin and the functional monomer, adopts a heterogeneous polymerization mode to improve the monomer concentration and the raw material utilization rate, synthesizes a solid olefin functional polymer, and adopts the plasma initiation polymerization to realize cleaner process and purer polymer, so that the polymer with high molecular weight is easier to prepare; the post-reaction treatment process is simple, easy to separate and purify, energy-saving and cost-reducing.

To achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for synthesizing an olefin functional polymer by plasma initiation, which comprises the following steps:

(1) After the low-carbon olefin is introduced into the reactor, the temperature and the pressure are raised, and after the reaction temperature and the reaction pressure are reached, the raw material liquid prepared by the functional monomer and the solvent is added into the reactor, and meanwhile, the plasma is introduced into the reactor to carry out polymerization reaction;

(2) And (3) carrying out gas-solid-liquid separation on the material obtained after the polymerization reaction in the step (1), recovering the low-carbon olefin, discharging the rest material, and carrying out solid-liquid separation to obtain the solid-phase olefin functional polymer and the liquid-phase material.

In the invention, for the synthesis of olefin functional polymers, the selection of olefin and functional monomers has an important influence on the performance of the polymers, the invention selects low-carbon gaseous olefin to react with liquid functional monomers, the difference of the phases of the low-carbon gaseous olefin and the liquid functional monomers leads the difficulty to be relatively higher when the low-carbon gaseous olefin and the functional monomers are liquid, and the low-carbon gaseous olefin generally does not contain side chains and has higher reaction difficulty compared with the liquid olefin; meanwhile, the invention adopts plasma to initiate polymerization, does not contain free radical initiator, has purer polymer, is easy to prepare high molecular weight polymer, has controllable polymer microsphere particle size and uniform distribution; the method is simple to operate, mild in reaction condition, recyclable in raw materials, simple in post-treatment process, easy to separate and purify, low in energy consumption, low in cost and environment-friendly.

The following technical scheme is a preferred technical scheme of the invention, but is not a limitation of the technical scheme provided by the invention, and the technical purpose and beneficial effects of the invention can be better achieved and realized through the following technical scheme.

As a preferred embodiment of the present invention, the low-carbon olefin in step (1) includes any one or a combination of at least two of ethylene, propylene, butene or butadiene, and typical, but non-limiting examples of the combination are: a combination of ethylene and propylene, a combination of propylene and butene, a combination of butene and butadiene, a combination of ethylene, propylene and butene, and the like.

Preferably, before the light olefins are introduced in the step (1), the reactor is vacuumized and then is replaced by a shielding gas.

Preferably, the evacuation and aeration processes are alternated, at least three times, for example three, four or five times, etc.

Preferably, the pressure in the reactor is atmospheric pressure by introducing a shielding gas each time, wherein the shielding gas comprises nitrogen.

Preferably, the reactor of step (1) comprises any one of a tank reactor, a tubular reactor, a microchannel reactor, a tower reactor, a fluidized bed reactor or an ebullated bed reactor.

As a preferred embodiment of the present invention, the functional monomer in step (1) includes any one or a combination of at least two of maleic anhydride, maleimide, maleic acid or methyl maleate, and typical but non-limiting examples of such combinations are: a combination of maleic anhydride and maleimide, a combination of maleimide and maleic acid, a combination of maleic acid and methyl maleate, a combination of maleic anhydride, maleimide and maleic acid, and the like.

Preferably, the solvent of step (1) comprises any one or a combination of at least two of organic alkanoates, alkanes or aromatics, typical but non-limiting examples of which are: a combination of an organic alkanoate compound and an alkane compound, a combination of an alkane compound and an aromatic hydrocarbon compound, a combination of an organic alkanoate compound, an alkane compound and an aromatic hydrocarbon compound, and the like.

Preferably, the alkanes include any one or a combination of at least two of n-hexane, cyclohexane, n-heptane, n-pentane, n-octane, or n-decane, typical but non-limiting examples of such combinations being: a combination of n-hexane and cyclohexane, n-hexane and n-heptane, a combination of cyclohexane and n-heptane, a combination of n-hexane, cyclohexane and n-heptane, and the like.

Preferably, the aromatic compounds include any one or a combination of at least two of benzene, toluene, ethylbenzene or xylene, typical but non-limiting examples of which are: benzene and ethylbenzene, benzene and toluene, ethylbenzene and xylene, benzene, ethylbenzene and xylene, and the like.

Preferably, the structural general formula of the organic alkyl acid ester compound isWherein R1 is any one of H, C-C20 alkyl or C6-C10 aryl, R2 is any one of C1-C20 alkyl or C6-C10 aryl, R1COOR2, R1 is any one of H, C-C10 alkyl or C1-C10 aryl, and R2 is any one of C1-C10 alkyl or C1-C10 aryl.

Preferably, the organic alkanoate compound includes any one or a combination of at least two of ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, amyl 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, or isoamyl phenylacetate, as typical but non-limiting examples: a combination of ethyl acetate and butyl acetate, a combination of butyl acetate and isobutyl acetate, a combination of butyl acetate and isoamyl acetate, and the like.

In a preferred embodiment of the present invention, the mass ratio of the solvent to the functional monomer in the step (1) is (2-50): 1, for example, 2:1, 5:1, 10:1, 20:1, 25:1, 30:1, 35:1, 40:1 or 50:1, etc., but the present invention is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.

Preferably, the raw material liquid in the step (1) is subjected to impurity removal and preheating before being added into a reactor.

In the invention, the raw material liquid needs to be preheated before feeding so as to ensure that monomers in the system are fully dissolved and are not separated out; meanwhile, the preheating temperature is not easy to be too high, so that the initiator is decomposed and consumed prematurely. If undissolved impurities exist after mixing, the undissolved impurities are removed by adopting operations such as filtration and the like.

Preferably, the raw material liquid in the step (1) is pumped into the reactor at a constant speed after being pressurized by a delivery pump.

As a preferred technical scheme of the invention, the plasma in the step (1) is generated by ionizing nitrogen by a DBD plasma generator.

Preferably, the DBD plasma generator is disposed outside the reactor.

In the invention, a DBD plasma generator is arranged outside a reactor, nitrogen is continuously injected into a pipeline of which an electrode plate is connected with the reactor for discharge ionization, and generated plasma is introduced into the reactor.

Preferably, the power of the DBD plasma generator is 0.5 to 2000W, for example, 0.5W, 5W, 20W, 50W, 100W, 250W, 500W, 800W, 1000W, 1200W, 1500W, 1800W or 2000W, etc., but not limited to the recited values, and other non-recited values within the range of values are equally applicable; the frequency is 0.5 to 400MHz, for example, 0.5MHz, 2MHz, 10MHz, 50MHz, 100MHz, 150MHz, 200MHz, 250MHz, 300MHz or 400MHz, etc., but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the mass ratio of the plasma to the functional monomer is (0.001-1): 1, for example, 0.001:1, 0.002:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.2:1, 0.5:1, 0.8:1 or 1:1, etc., but not limited to the recited values, other non-recited values within the range of values are equally applicable.

In the invention, the power and frequency parameters of the plasma generator can influence the monomer conversion rate, the molecular weight and the particle size of a polymerization product, wherein the frequency is increased along with the increase of the power of equipment, and the increase of the frequency can accelerate the polymerization speed in the reaction process, but the too high speed can influence the molecular weight and the particle size of the polymerization product. After the plasma is added, the plasma can interact with the functional monomer to form nitrogen free radicals, and the difference of the mass ratio of the plasma to the functional monomer can lead to the difference of the concentration of the free radicals of the system, thereby influencing the polymerization effect.

In a preferred embodiment of the present invention, the polymerization reaction in the step (1) is carried out at a temperature of 30 to 80 ℃, for example, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃ or the like, but the polymerization reaction is not limited to the above-mentioned values, and other values not shown in the above-mentioned value range are similarly applicable.

In the invention, because the plasma is adopted to initiate the polymerization reaction, the reaction can be initiated without too high reaction temperature compared with the initiation of the polymerization reaction by the initiator based on the characteristics of large kinetic energy and active chemical property of the plasma particles; the initiator in the initiator initiation polymerization is easily interfered by external temperature, humidity and other factors, so that the initiator loses initiation capability, and the polymerization is influenced; and the plasma-initiated polymerization reaction is not easily affected by the environment, and the plasma equipment continuously generates plasma to initiate polymerization.

Preferably, the pressure of the polymerization reaction in the step (1) is 0.1 to 10MPa, for example, 0.1MPa, 0.5MPa, 1MPa, 3MPa, 5MPa, 6MPa, 8MPa or 10MPa, etc., but the polymerization reaction is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.

Preferably, the residence time of the raw material liquid in step (1) is 0.01 to 10 hours, for example, 0.01 hours, 0.1 hours, 0.5 hours, 1 hour, 3 hours, 5 hours, 6 hours, 8 hours or 10 hours, etc., but is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.

Preferably, in the polymerization reaction process in the step (1), the pressure is maintained by continuously introducing the low-carbon olefin.

According to the preferred technical scheme, the low-carbon olefin is discharged in the gas-solid-liquid separation process in the step (2) for recycling, and nitrogen is used for replacement.

Preferably, the residual materials after the low-carbon olefin is recovered in the step (2) are discharged in a solid-liquid mode.

Preferably, the discharged low-carbon olefin is pressurized and returned to the step (1) for reuse.

As a preferred embodiment of the present invention, the solid-liquid separation method of step (2) comprises any one or a combination of at least two of decantation, filtration or centrifugation, and typical but non-limiting examples of such combinations are: a combination of decantation and filtration, a combination of filtration and centrifugation, etc., preferably press filtration.

Preferably, the residual materials are subjected to filter pressing by adopting a protective gas, and the obtained filter cake is washed, dried and crushed.

Preferably, the washing is performed with the solvent of step (1), and furthermore ether compounds comprising any one or a combination of at least two of C1-C10 saturated ether compounds, preferably diethyl ether and/or propyl ether, may also be used.

Preferably, the olefin functional polymer in the step (2) is a microspheroidal particle having a particle diameter of 10 to 50. Mu.m, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, etc., but not limited to the values recited, and other values not recited in the range are equally applicable.

As a preferable technical scheme of the invention, the liquid phase material in the step (2) is separated, and the obtained recovered solvent is returned to the step (1) for reuse.

Preferably, the liquid phase material separation process comprises any one or a combination of at least two of distillation, membrane separation, washing or extraction, typical but non-limiting examples of which are: a combination of distillation and membrane separation, a combination of distillation and extraction, a combination of distillation, membrane separation and washing, and the like, preferably distillation, and more preferably rectification.

Preferably, the recovered solvent in step (3) is returned to step (1) and/or step (2) is reused, raw material liquid is prepared and/or filter cake is washed.

As a preferred technical solution of the present invention, the method comprises the steps of:

(1) The method comprises the steps of introducing low-carbon olefin into a reactor, heating and boosting the pressure, vacuumizing the reactor and introducing nitrogen into normal pressure before introducing the low-carbon olefin, wherein the vacuumizing and introducing nitrogen are alternately carried out, the process is repeated at least twice, the low-carbon olefin comprises any one or a combination of at least two of ethylene, propylene, butylene and butadiene, the reactor comprises any one of a kettle type reactor, a tubular reactor, a micro-channel reactor, a tower type reactor, a fluidized bed reactor or a boiling bed reactor, the mass ratio of the solvent to the functional monomer (2-50): 1, the plasma generated by a DBD plasma generator is introduced into the reactor at the same time, the polymerization frequency of the plasma generated by the DBD plasma generator is 0.001-0.01 MHz, the polymerization frequency of the plasma generated by the DBD plasma generator is 0.01-0.01 MHz, the pressure of the plasma generated by the polymerization is kept at the time of 0.0.0-0.0.01 MHz, and the continuous time is kept at the plasma generated by the polymerization frequency of 0.0-0.0.01 MHz, and the pressure of the plasma generated by the DBD plasma generator is kept at the polymerization time is kept at the pressure of 0.0-0.0.01-0.0.001 MHz;

(2) The material after the polymerization reaction in the step (1) is subjected to gas-solid-liquid separation, low-carbon olefin is recovered, discharged low-carbon olefin is pressurized and returned to the step (1) for reuse, the rest material is discharged in a solid-liquid mode and subjected to solid-liquid separation, filter pressing is carried out by adopting protective gas, and the obtained filter cake is washed, dried and crushed to obtain a solid-phase olefin functional polymer and a liquid-phase material, wherein the olefin functional polymer is microspherical particles with the particle size of 10-50 mu m;

(3) Separating the liquid phase material obtained in the step (2), wherein the separation method comprises any one or a combination of at least two of distillation, membrane separation, washing or extraction, and the obtained recovered solvent is returned to the step (1) and/or used in the step (2) again for preparing raw material liquid and/or washing filter cakes.

Compared with the prior art, the invention has the following beneficial effects:

(1) The method realizes the same-chain alternating copolymerization of the low-carbon gaseous olefin and the functional monomer through the pressurized reaction of the low-carbon gaseous olefin and the functional monomer, adopts a heterogeneous polymerization mode, improves the monomer concentration and the raw material utilization rate, and synthesizes the solid olefin functional polymer with high reaction efficiency;

(2) The invention adopts plasma to initiate polymerization, does not contain free radical initiator, has purer polymer, is easy to prepare high molecular weight polymer, has controllable polymer microsphere particle size and uniform distribution, has simple post-treatment process, is easy to separate and purify, and can recycle raw materials;

(3) The method disclosed by the invention is simple to operate, mild in reaction condition, low in cost and environment-friendly, and saves energy consumption.

Detailed Description

For better illustrating the present invention, the technical scheme of the present invention is convenient to understand, and the present invention is further described in detail below. The following examples are merely illustrative of the present invention and are not intended to represent or limit the scope of the invention as defined in the claims.

The present invention provides in part a method for plasma initiated synthesis of functional olefin polymers, the method comprising the steps of:

The following are exemplary but non-limiting examples of the invention:

example 1:

the present embodiment provides a method for synthesizing an olefin functional polymer by plasma initiation, comprising the following steps:

(1) Heating and boosting the low-carbon olefin after the low-carbon olefin is introduced into a tubular reactor, vacuumizing the reactor and introducing nitrogen to normal pressure before the low-carbon olefin is introduced, alternately performing vacuumizing and introducing nitrogen for three times, pumping raw material liquid prepared from functional monomers and solvent into the tubular reactor at a constant speed after the reaction temperature and the reaction pressure are reached, wherein the functional monomers are maleic anhydride, the solvent is ethyl acetate and butyl acetate with the volume ratio of 1:1, the mass ratio of the solvent to the functional monomers is 20:1, simultaneously introducing plasma generated by ionizing nitrogen by a DBD plasma generator into the reactor, performing polymerization reaction, wherein the power of the DBD plasma generator is 60W, the frequency is 30MHz, the mass ratio of the plasma to the functional monomers is 0.01:1, the temperature of the polymerization reaction is 50 ℃, the pressure is 5MPa, the retention time is 5h, and continuously introducing the low-carbon olefin to maintain the pressure during the polymerization reaction;

(2) Carrying out gas-solid-liquid separation on the materials obtained after the polymerization reaction in the step (1), recovering low-carbon olefin, pressurizing the discharged low-carbon olefin, returning to the step (1) for reuse, discharging the rest materials in a solid-liquid mode, carrying out filter pressing by adopting nitrogen, washing and drying the obtained filter cake, crushing, and obtaining solid-phase olefin functional polymer and liquid-phase material by using normal hexane as a solvent for washing, wherein the olefin functional polymer is microspherical particles;

(3) And (3) rectifying and separating the liquid phase material obtained in the step (2), wherein the distilled overhead fraction is recovered component solvents, and the recovered component solvents are returned to the step (1) and the step (2) for reuse and are used for preparing raw material liquid and washing filter cakes.

Example 2:

(1) Heating up and boosting after low-carbon olefin is introduced into a microchannel reactor, wherein the low-carbon olefin is ethylene, before the low-carbon olefin is introduced, the reactor is vacuumized and then nitrogen is introduced to normal pressure, the vacuumizing and nitrogen introducing processes are alternately carried out for three times, after the reaction temperature and the reaction pressure are reached, raw material liquid prepared from functional monomers and solvent is pumped into the reactor at a constant speed, the functional monomers are maleic anhydride, the solvent is butyl acetate, the mass ratio of the solvent to the functional monomers is 4:1, meanwhile, plasma generated by ionizing nitrogen by a DBD plasma generator is introduced into the reactor for polymerization reaction, the power of the DBD plasma generator is 250W, the frequency is 100MHz, the mass ratio of the plasma addition amount to the functional monomers is 0.1:1, the temperature of the polymerization reaction is 30 ℃, the pressure is 10MPa, the retention time is 1h, and the low-carbon olefin is continuously introduced in the polymerization process for maintaining the pressure;

(2) Carrying out gas-solid-liquid separation on the materials obtained after the polymerization reaction in the step (1), recovering low-carbon olefin, pressurizing the discharged low-carbon olefin, returning to the step (1) for reuse, discharging the rest materials in a solid-liquid mode, carrying out pressure filtration by adopting nitrogen, washing and drying the obtained filter cake, crushing, and obtaining solid-phase olefin functional polymer and liquid-phase material by using butyl acetate as a washing solvent, wherein the olefin functional polymer is microspherical particles;

(3) Distilling the liquid phase material obtained in the step (2), and returning the distilled overhead fraction to the step (1) for reuse to prepare a raw material liquid.

Example 3:

(1) Heating and boosting after low-carbon olefin is introduced into a kettle type reactor, wherein the low-carbon olefin is ethylene, before the low-carbon olefin is introduced, the reactor is vacuumized and then nitrogen is introduced to normal pressure, the vacuumizing and nitrogen introducing processes are alternately carried out for two times, after the reaction temperature and the reaction pressure are reached, raw material liquid prepared from functional monomers and solvent is pumped into the kettle type reactor at a constant speed, the functional monomers are maleic anhydride, the solvent is ethyl acetate, the mass ratio of the solvent to the functional monomers is 50:1, meanwhile, plasma generated by ionizing nitrogen by a DBD plasma generator is introduced into the reactor for polymerization reaction, the power of the DBD plasma generator is 1W, the frequency is 2MHz, the mass ratio of the plasma adding amount to the functional monomers is 0.005:1, the temperature of the polymerization reaction is 80 ℃, the pressure is 6MPa, the retention time is 10h, and the low-carbon olefin is continuously introduced into the reactor for maintaining the pressure in the polymerization process;

(2) Separating gas from solid and liquid of the materials obtained after the polymerization reaction in the step (1), recovering low-carbon olefin, pressurizing the discharged low-carbon olefin, returning to the step (1) for reuse, discharging the rest materials in a solid-liquid mode, performing filter pressing by adopting nitrogen, washing and drying the obtained filter cake, crushing, and obtaining solid-phase olefin functional polymer and liquid-phase material by using ethyl acetate as a washing solvent, wherein the olefin functional polymer is microspherical particles;

(3) And (3) distilling and separating the liquid phase material obtained in the step (2), and returning the distilled overhead fraction to the step (1) and the step (2) for reuse, so as to prepare raw material liquid and wash filter cakes.

Example 4:

(1) Heating and boosting the low-carbon olefin after the low-carbon olefin is introduced into a tubular reactor, vacuumizing the reactor and introducing nitrogen to normal pressure before the low-carbon olefin is introduced, alternately performing vacuumizing and introducing nitrogen for three times, pumping raw material liquid prepared from functional monomers and solvent into the tubular reactor at a constant speed after the reaction temperature and the reaction pressure are reached, wherein the functional monomers are maleimide, the solvent is benzene and dimethylbenzene with the volume ratio of 1:1, the mass ratio of the solvent to the functional monomers is 10:1, simultaneously introducing plasma generated by ionizing nitrogen by a DBD plasma generator into the reactor, performing polymerization reaction, wherein the power of the DBD plasma generator is 100W, the frequency is 200MHz, the mass ratio of the plasma addition amount to the functional monomers is 0.05:1, the temperature of the polymerization reaction is 60 ℃, the pressure is 1MPa, the residence time is 6h, and continuously introducing the low-carbon olefin to maintain the pressure during the polymerization reaction;

(3) And (3) rectifying and separating the liquid phase material obtained in the step (2), wherein the distilled overhead fraction is recovered component solvents, and the recovered component solvents are returned to the step (1) and the step (2) for reuse respectively and are used for preparing raw material liquid and washing filter cakes.

Example 5:

(1) Introducing low-carbon olefin into a fluidized bed reactor, heating and boosting the temperature, wherein the low-carbon olefin is propylene, vacuumizing the reactor and introducing nitrogen to normal pressure before introducing the low-carbon olefin, alternately carrying out vacuumizing and introducing nitrogen four times, pumping raw materials prepared from functional monomers and solvents into the fluidized bed reactor after reaching the reaction temperature and the reaction pressure, wherein the functional monomers are maleic acid, the solvents are ethylbenzene, the mass ratio of the solvents to the functional monomers is 30:1, introducing plasma generated by ionizing nitrogen by a DBD plasma generator into the reactor to carry out polymerization reaction, wherein the power of the DBD plasma generator is 1000W, the frequency is 300MHz, the mass ratio of the plasma addition amount to the functional monomers is 0.2:1, the temperature of the polymerization reaction is 40 ℃, the pressure is 8MPa, the retention time is 0.1h, and continuously introducing the low-carbon olefin in the polymerization reaction process to maintain the pressure;

(2) Separating gas from solid and liquid of the materials obtained after the polymerization reaction in the step (1), recovering low-carbon olefin, pressurizing the discharged low-carbon olefin, returning to the step (1) for reuse, discharging the rest materials in a solid-liquid mode, performing filter pressing by adopting nitrogen, washing and drying the obtained filter cake, crushing, and obtaining solid-phase olefin functional polymer and liquid-phase material by using butyl acetate as a washing solvent, wherein the olefin functional polymer is microspherical particles;

Example 6:

(1) Heating and boosting after low-carbon olefin is introduced into a kettle type reactor, wherein the low-carbon olefin is ethylene, the reactor is vacuumized and then nitrogen is introduced into the reactor to normal pressure before the low-carbon olefin is introduced, the vacuumizing and nitrogen introducing processes are alternately carried out for three times, after the reaction temperature and the reaction pressure are reached, raw materials prepared from functional monomers and solvents are pumped into the kettle type reactor, the functional monomers are maleic anhydride, the solvents are butyl acetate and cyclohexane in a volume ratio of 5:1, the mass ratio of the solvents to the functional monomers is 15:1, meanwhile, plasma generated by ionizing nitrogen by a DBD plasma generator is introduced into the reactor to carry out polymerization, the power of the DBD plasma generator is 2000W, the frequency is 400MHz, the mass ratio of the plasma to the functional monomers is 1:1, the temperature of the polymerization reaction is 70 ℃, the pressure is 3MPa, the residence time is 2h, and the low-carbon olefin is continuously introduced into the reactor to maintain the pressure during the polymerization process;

(2) Separating gas from solid and liquid of the materials obtained after the polymerization reaction in the step (1), recovering low-carbon olefin, pressurizing the discharged low-carbon olefin, returning to the step (1) for reuse, discharging the rest materials in a solid-liquid mode, performing filter pressing by adopting nitrogen, washing and drying the obtained filter cake, crushing, and obtaining solid-phase olefin functional polymer and liquid-phase material by using cyclohexane as a solvent, wherein the olefin functional polymer is microspherical particles;

Comparative example 1:

this comparative example provides a process for the synthesis of an olefin functional polymer, with reference to the process in example 1, with the difference that: in the step (1), plasma initiation is not adopted, namely a plasma generating device is not adopted, but an initiator benzoyl peroxide is adopted for initiation, and the molar ratio of the initiator to the functional monomer is 0.01:1; the reaction temperature was 80 ℃.

The conversion of the functional monomer, the yield of the olefin functional polymer and the acid anhydride value were calculated from the tests of the raw material monomer and the olefin functional polymer in the above examples and comparative examples, and the particle diameter and the weight average molecular weight of the polymer were tested and calculated, and the results are shown in table 1.

TABLE 1 data on the results of the polymerization reactions in examples 1-6 and comparative example 1

As can be seen from Table 1, the conversion rate of the functional monomer can reach more than 90% and the yield of the polymer can reach more than 90%, the anhydride value of the polymer is more than 69%, the particle size range is between 10 and 50 μm, the weight average molecular weight can reach more than 70000, in the embodiment, by using plasma as the initiator, the polymerization is initiated by the initiator in comparative example 1, the polymer with relatively high molecular weight is more easily synthesized, and meanwhile, the side reaction is less because the plasma is not easy to decompose, and the reaction selectivity is relatively improved.

It can be seen from the above examples and comparative examples that the method of the invention realizes the same-chain alternating copolymerization of the low-carbon gaseous olefin and the functional monomer by the pressurized reaction of the two, adopts a heterogeneous polymerization mode, improves the monomer concentration and the raw material utilization rate, and synthesizes the solid olefin functional polymer with high reaction efficiency; the invention adopts plasma to initiate polymerization, does not contain free radical initiator, has purer polymer, is easy to prepare high molecular weight polymer, has controllable polymer microsphere particle diameter and uniform distribution, has simple post-treatment process, is easy to separate and purify, can recycle raw materials, and improves the conversion rate of the raw materials and the yield of products; the method is simple to operate, mild in reaction condition, low in cost and environment-friendly, and energy consumption is saved.

The present invention is described in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e., it does not mean that the present invention must be practiced depending on the above detailed methods. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions for the method of the present invention, addition of auxiliary steps, selection of specific modes, etc., are within the scope of the present invention and the scope of the disclosure.

Claims

1. A method for plasma initiated synthesis of an olefin functional polymer, the method comprising the steps of:

2. The method of claim 1, wherein the low carbon olefin of step (1) comprises any one or a combination of at least two of ethylene, propylene, butene, or butadiene;

preferably, before the light olefins are introduced in the step (1), the reactor is vacuumized and then is replaced by a protective gas;

preferably, the vacuumizing and shielding gas introducing processes are alternately performed, and the process is repeated for at least three times;

preferably, the protective gas is introduced each time until the pressure in the reactor is normal pressure, wherein the protective gas comprises nitrogen;

3. The method of claim 1 or2, wherein the functional monomer of step (1) comprises any one or a combination of at least two of maleic anhydride, maleimide, maleic acid, or methyl maleate;

preferably, the solvent in the step (1) comprises any one or a combination of at least two of organic alkanoate compounds, alkane compounds or aromatic hydrocarbon compounds;

preferably, the structural general formula of the organic alkyl acid ester compound isWherein R1 is any one of H, C1-C20 alkyl or C6-C10 aryl, and R2 is any one of C1-C20 alkyl or C6-C10 aryl;

preferably, the alkane compound comprises any one or a combination of at least two of n-hexane, cyclohexane, n-pentane, n-heptane, n-octane or n-decane;

preferably, the aromatic hydrocarbon compound comprises any one or a combination of at least two of benzene, toluene, ethylbenzene or xylene.

4. A process according to any one of claims 1 to 3, wherein the mass ratio of solvent to functional monomer in step (1) is (2 to 50): 1;

preferably, the raw material liquid in the step (1) is subjected to impurity removal and preheating before being added into a reactor;

5. The method of any one of claims 1-4, wherein the plasma of step (1) is generated by ionizing nitrogen gas by a DBD plasma generator;

preferably, the DBD plasma generator is disposed outside the reactor;

preferably, the power of the DBD plasma generator is 0.5-2000W, and the frequency is 0.5-400 MHz;

preferably, the mass ratio of the plasma added to the functional monomer in the polymerization reaction in the step (1) is (0.001-1): 1.

6. The process of any one of claims 1-5, wherein the temperature of the polymerization reaction of step (1) is 30-80 ℃;

preferably, the pressure of the polymerization reaction in the step (1) is 0.1-10 MPa;

preferably, the retention time of the raw material liquid in the step (1) is 0.01-10 h;

7. The method according to any one of claims 1 to 6, wherein the low-carbon olefin is discharged for recovery in the gas-solid-liquid separation process of step (2);

preferably, the residual materials after the low-carbon olefin is recovered in the step (2) are discharged in a solid-liquid mode;

8. The process according to any one of claims 1 to 7, wherein the solid liquid separation process of step (2) comprises any one or a combination of at least two of decantation, filtration or centrifugation, preferably filter pressing;

preferably, the residual materials are subjected to filter pressing by adopting a protective gas, and the obtained filter cake is crushed after washing and drying;

preferably, the olefin functional polymer in the step (2) is microspherical particles with the particle size of 10-50 μm.

9. The method according to any one of claims 1 to 8, wherein the liquid phase material of step (2) is separated and the recovered solvent obtained is returned to step (1) for reuse;

preferably, the liquid phase material separation method comprises any one or at least two of distillation, membrane separation, washing or extraction, preferably distillation, further preferably rectification;

preferably, the recovered solvent is returned to step (1) and/or step (2) for reuse, raw material liquid is prepared and/or filter cake is washed.

10. The method according to any one of claims 1-9, characterized in that the method comprises the steps of:

(1) The method comprises the steps of introducing low-carbon olefin into a reactor, heating and boosting the pressure, vacuumizing the reactor and introducing nitrogen into normal pressure before introducing the low-carbon olefin, wherein the vacuumizing and introducing nitrogen are alternately carried out, the process is repeated for at least three times, the low-carbon olefin comprises any one or a combination of at least two of ethylene, propylene, butylene and butadiene, the reactor comprises a kettle type reactor, a tubular type reactor, a micro-channel reactor, a tower type reactor, a fluidized bed reactor or a boiling bed reactor, the mass ratio of the solvent to the functional monomer (2-50): 1, the plasma generated by a DBD plasma generator is introduced into the reactor at the same time, the polymerization frequency of the plasma generated by the DBD plasma generator is 0.001-0.01 MHz, the polymerization frequency of the plasma generated by the DBD plasma generator is 0.01-0.10 MHz, and the retention time is 0.0.01-0.10 MHz, and the pressure of the plasma generated by the polymerization is maintained at the same time is 0.0-0.0.0.0 MHz, and the pressure of the plasma generated by the polymerization is maintained at the polymerization reactor is maintained at the same time;