Method for synthesizing olefin functional polymer under assistance of microwave irradiation

Abstract

The invention provides a microwave irradiation-assisted olefin functional polymer synthesis method, which comprises: (1) introducing low-carbon olefin into a reactor until a reaction pressure is reached, adding a raw material liquid prepared from a functional monomer and a solvent into the reactor, and carrying out microwave irradiation on the reactor to carry out a polymerization reaction; (2) cooling and depressurizing the system after the polymerization reaction to discharge low-carbon olefin, returning the discharged low-carbon olefin to the step (1) for reuse, and performing solid-liquid separation on the residual material to obtain a solid-phase olefin functional polymer and a liquid-phase material; and (3) rectifying the liquid-phase material, and returning the rectified fraction to the step (1) for reuse. The microwave irradiation is adopted to assist in initiating polymerization, the heating speed is high, side reactions are few, the polymer is pure, the polymer with high molecular weight is easy to prepare, the particle size of the polymer microspheres is controllable, distribution is uniform, the aftertreatment process is simple, separation and purification are easy, and raw materials can be recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of organic polymerization and relates to a method for synthesizing olefin functional polymers assisted by microwave irradiation. Background Art

[0002] As functional polymer materials, olefin functional polymers have a wide range of uses in engineering plastic chain extension, high-performance composite materials, nylon impregnation, ink dispersion, microencapsulation, and filter membrane formation, and have received great attention. There are a large number of active groups on the molecular chain of olefin functional polymers, which can react with a variety of functional groups, such as the terminal hydroxyl or terminal amino groups of nylon products, to increase the molecular weight of nylon, improve the mechanical properties, and adjust the viscosity of nylon; in addition, olefin functional polymers can be used in the preparation of microcapsules, and also have good application prospects in the fields of pesticides, fragrances, and medicines.

[0003] The synthetic raw materials of olefin functional polymers are mainly olefins and functional monomers. The currently available polymerization methods include emulsion polymerization, suspension polymerization and precipitation polymerization. The former two require the use of a large amount of stabilizers, which remain on the polymer particles through physical adsorption or chemical adsorption and affect their performance. Although precipitation polymerization does not require the addition of stabilizers, the concentration of polymerized monomers in the traditional precipitation polymerization system is low, resulting in low polymerization efficiency, and therefore the polymerization method needs to be improved.

[0004] Therefore, in the art, it is desired to develop a method for synthesizing olefin functional polymers with simple process, high polymerization efficiency, few side reactions and pure polymers. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for synthesizing olefin functional polymers assisted by microwave irradiation. The method realizes the same-chain alternating copolymerization of low-carbon gaseous olefins and functional monomers through a pressurized reaction, and adopts a heterogeneous polymerization method to improve the monomer concentration and raw material utilization rate, synthesize solid olefin functional polymers, and adopts microwave irradiation to assist in initiating polymerization, so that the process is cleaner, the side reactions are less, the polymer is pure, and it is easier to prepare high molecular weight polymers; the post-reaction treatment process is simple, easy to separate and purify, save energy consumption, and reduce costs.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0008] (1) introducing a low carbon olefin into a reactor until the reaction pressure is reached, and then adding a raw material solution prepared by a functional monomer and a solvent into the reactor until the two are fully mixed; and then irradiating the reactor with microwaves to cause a polymerization reaction;

[0009] (2) cooling and depressurizing the system after the polymerization reaction in step (1) to discharge the light olefins, returning the discharged light olefins to step (1) for reuse, and performing solid-liquid separation of the remaining materials to obtain a solid-phase olefin functional polymer and a liquid-phase material;

[0010] (3) The liquid phase material obtained in step (2) is distilled, and the distilled fraction is returned to step (1) for reuse.

[0011] In the present invention, for the synthesis of olefin functional polymers, the selection of olefins and functional monomers has an important influence on the performance of the polymers. The present invention selects low-carbon gaseous olefins to react with liquid functional monomers. The difference in phase between the two makes it relatively difficult to react with the olefins and the functional monomers when both are liquid. In addition, low-carbon gaseous olefins usually do not contain side chains, and are more difficult to react with than liquid olefins. The present invention improves the monomer concentration and reaction rate, improves the raw material conversion rate and product yield through pressurized reaction and heterogeneous polymerization, and realizes the same-chain alternating copolymerization of gaseous olefin monomers and functional monomers. At the same time, the present invention adopts microwave irradiation to assist in initiating polymerization, has a fast heating speed, is selective for heating materials, is easy to prepare high-molecular-weight polymers, and has controllable and uniformly distributed polymer microspheres. The method is simple to operate, mild reaction conditions, recyclable raw materials, simple post-processing process, easy to separate and purify, saves energy consumption, has low cost, and is green and environmentally friendly.

[0012] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0013] Preferably, the low-carbon olefin in step (1) comprises any one of ethylene, propylene, butene or butadiene, or a combination of at least two of them. Typical but non-limiting examples of the combination include: 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, etc.

[0014] Preferably, before the light olefin is introduced in step (1), the reactor is first evacuated and then replaced with a protective gas.

[0015] Preferably, the protective gas comprises nitrogen or argon.

[0016] Preferably, the reactor in step (1) comprises any one of a tank reactor, a tubular reactor, a microchannel reactor or a tower reactor.

[0017] Preferably, the reaction pressure in step (1) is 0.1 to 10 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 3 MPa, 5 MPa, 6 MPa, 8 MPa or 10 MPa, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the functional monomer in step (1) comprises any one of maleic anhydride, maleimide, maleic acid or methyl maleate, or a combination of at least two of them. Typical but non-limiting examples of the combination include: 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, etc.

[0019] Preferably, the solvent in step (1) comprises any one of organic alkanoate compounds, alkane compounds or aromatic compounds, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of organic alkanoate compounds and alkane compounds, a combination of alkane compounds and aromatic compounds, a combination of organic alkanoate compounds, alkane compounds and aromatic compounds, etc.

[0020] 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, 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 or isoamyl phenylacetate. Typical but non-limiting examples of the combination include: 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.

[0021] Preferably, the alkane compound includes any one of cyclohexane, n-hexane or n-heptane, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of cyclohexane and n-hexane, a combination of n-hexane and n-heptane, a combination of cyclohexane, n-hexane and n-heptane, etc.

[0022] Preferably, the aromatic hydrocarbon compound includes any one of benzene, ethylbenzene or xylene, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of benzene and ethylbenzene, a combination of ethylbenzene and xylene, a combination of benzene, ethylbenzene and xylene, etc.

[0023] Preferably, the mass ratio of the solvent to the functional monomer in 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, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the raw material liquid in step (1) is firstly decontaminated and preheated before being added to the reactor.

[0025] As a preferred technical solution of the present invention, the raw material liquid needs to be preheated before feeding to ensure that the monomers in the system are fully dissolved and not precipitated. If there are undissolved impurities after mixing, they need to be removed by filtering or other operations.

[0026] Preferably, the raw material liquid in step (1) is pressurized by a delivery pump and then pumped into the reactor at a uniform speed.

[0027] In the present invention, since the low-carbon olefins are first introduced into the reactor and pressurized, the raw material liquid also needs to be pressurized in advance before it can be introduced.

[0028] Preferably, the microwaves used in the microwave irradiation in step (1) are generated by a microwave generator.

[0029] Preferably, the microwave generator is arranged outside the reactor.

[0030] In the present invention, the microwave generator generates microwaves to irradiate the reactor and increase the temperature of the polymerization system to initiate the reaction.

[0031] Preferably, the power of the microwave generator is 0.5-2000 W, for example 0.5 W, 5 W, 20 W, 50 W, 100 W, 250 W, 500 W, 800 W, 1000 W, 1200 W, 1500 W, 1800 W or 2000 W, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In the present invention, the power parameter of the microwave generator will affect the monomer conversion rate, the molecular weight and the particle size of the polymerized product.

[0033] Preferably, the polymerization reaction temperature in step (1) is 30-80°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] In the present invention, since microwave irradiation is used to assist in initiating the polymerization reaction, based on the energy transfer property of microwave irradiation, compared with the traditional polymerization method, the reaction can be initiated without other heat sources.

[0035] Preferably, the pressure of the polymerization reaction in step (1) is 0.1 to 10 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 3 MPa, 5 MPa, 6 MPa, 8 MPa or 10 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the microwave irradiation time in step (1) is 0.01 to 10 h, for example, 0.01 h, 0.1 h, 0.5 h, 1 h, 3 h, 5 h, 6 h, 8 h or 10 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, during the polymerization reaction in step (1), light olefins are continuously introduced to maintain the pressure.

[0038] Preferably, during the cooling and pressure reduction process in step (2), light olefins are discharged and replaced with protective gas, and the protective gas includes nitrogen or argon.

[0039] Preferably, the low-carbon olefins discharged in step (2) are pressurized and returned to step (1) for reuse.

[0040] Preferably, the pressure of the low-carbon olefins discharged in step (2) after pressurization is 0.1 to 10 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 3 MPa, 5 MPa, 6 MPa, 8 MPa or 10 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the solid-liquid separation in step (2) comprises filtration, preferably filter pressing.

[0042] Preferably, the remaining material is filter-filtered using protective gas, and the obtained filter cake is washed, dried and then crushed.

[0043] Preferably, the solid phase olefin functional polymer in step (2) is in the form of microspherical particles having a particle size of 10 to 60 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the top temperature of the distillation in step (3) is 40-150°C, for example, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C, 140°C or 150°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable; the pressure is 0.1-101 kPa, for example, 0.1 kPa, 1 kPa, 5 kPa, 10 kPa, 30 kPa, 50 kPa, 60 kPa, 80 kPa or 101 kPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0045] In the present invention, the selection of the distillation temperature is mainly based on the boiling point of the solvent under a specific pressure.

[0046] Preferably, the top fraction after distillation in step (3) is returned to step (1) and reused to prepare the raw material liquid.

[0047] As a preferred technical solution of the present invention, the method comprises the following steps:

[0048] (1) introducing a low-carbon olefin into a reactor, wherein the low-carbon olefin includes any one of ethylene, propylene, butene or butadiene or a combination of at least two thereof, and the reactor includes any one of a kettle reactor, a tubular reactor, a microchannel reactor or a tower reactor, and after the reaction pressure reaches 0.1 to 10 MPa, pumping a raw material liquid prepared from a functional monomer and a solvent into the reactor, wherein the functional monomer includes any one of maleic anhydride, maleimide, maleic acid or methyl maleate or a combination of at least two thereof, and the solvent includes organic alkanoates, alkane compounds or any one or a combination of at least two of aromatic hydrocarbon compounds, the mass ratio of the solvent to the functional monomer is (2-50):1, and then the reactor is subjected to microwave irradiation, the microwave used in the microwave irradiation is generated by a microwave generator, the power of the microwave generator is 0.5-2000W, the microwave irradiation time is 0.01-10h, a polymerization reaction occurs, the polymerization reaction temperature is 30-80°C, and is adjusted by the microwave power, the pressure is 0.1-10MPa, and low-carbon olefins are continuously introduced during the polymerization reaction to maintain the pressure;

[0049] (2) cooling and depressurizing the system after the polymerization reaction in step (1) to discharge the light olefins, and returning the discharged light olefins to step (1) for reuse after pressurization, wherein the pressure of the light olefins after pressurization is 0.1 to 10 MPa, and the remaining materials are separated into solid and liquid, and the remaining materials are filtered by 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 solid-phase olefin functional polymer is a microspherical particle with a particle size of 10 to 60 μm;

[0050] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 40-150° C. and the pressure is 0.1-101 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) The method of the present invention realizes the same-chain alternating copolymerization of low-carbon gaseous olefins and functional monomers through a pressurized reaction, and adopts a heterogeneous polymerization method to improve the monomer concentration and raw material utilization rate, synthesize solid olefin functional polymers, and have high reaction efficiency;

[0053] (2) The present invention uses microwave irradiation to assist initiation of polymerization, which has a fast heating speed, few side reactions, relatively pure polymers, and is easy to prepare high molecular weight polymers. The particle size of polymer microspheres is controllable and evenly distributed. The post-processing process is simple, easy to separate and purify, and the raw materials can be recycled;

[0054] (3) The method of the present invention is simple to operate, has mild reaction conditions, saves energy, has low cost, and is environmentally friendly. DETAILED DESCRIPTION

[0055] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0056] Example 1

[0057] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0058] (1) introducing a low-carbon olefin into a tubular reactor and increasing the pressure to a specified pressure, wherein the low-carbon olefin is ethylene and nitrogen is first introduced before the low-carbon olefin is introduced. After reaching the reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the tubular reactor, wherein the functional monomer is maleic anhydride, and the solvent is ethyl acetate and butyl acetate in a volume ratio of 1:1, and the mass ratio of the solvent to the functional monomer is 20:1. The reactor is irradiated with microwaves, wherein the microwaves are generated by a microwave generator, and the power of the microwave generator is 200 W. A polymerization reaction occurs, wherein the temperature of the polymerization reaction is 50° C., the pressure is 5 MPa, and the residence time is 5 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0059] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged light olefins to 5 MPa and returning to step (1) for reuse, filtering the remaining materials with nitrogen, washing, drying and crushing the obtained filter cake to obtain a solid phase olefin functional polymer and a liquid phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0060] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 80° C. and the pressure is 50 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0061] Example 2

[0062] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0063] (1) A low-carbon olefin is introduced into a microchannel reactor and then the pressure is increased to a specified pressure, wherein the low-carbon olefin is ethylene and nitrogen is first introduced before the low-carbon olefin is introduced. After reaching the reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the reactor, wherein the functional monomer is maleic anhydride and the solvent is butyl acetate, and the mass ratio of the solvent to the functional monomer is 4:1. The reactor is irradiated with microwaves, wherein the microwaves are generated by a microwave generator with a power of 150 W, and a polymerization reaction occurs. The polymerization reaction temperature is 30° C., the pressure is 10 MPa, and the residence time is 1 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0064] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged light olefins to 10 MPa and returning to step (1) for reuse, filtering the remaining materials with nitrogen, washing, drying and crushing the obtained filter cake to obtain a solid phase olefin functional polymer and a liquid phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0065] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 126° C. and the pressure is 101 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0066] Example 3

[0067] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0068] (1) After a low-carbon olefin is introduced into a reactor and the pressure is increased to a specified pressure, the low-carbon olefin is ethylene, and nitrogen is first introduced before the low-carbon olefin is introduced. After reaching the reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the reactor, the functional monomer is maleic anhydride, the solvent is ethyl acetate, and the mass ratio of the solvent to the functional monomer is 50:1, and the reactor is irradiated with microwaves, the microwaves are generated by a microwave generator, the power of the microwave generator is 300 W, and a polymerization reaction occurs. The polymerization reaction temperature is 80° C., the pressure is 2 MPa, and the residence time is 8 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0069] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged low-carbon olefins to 2 MPa and returning to step (1) for reuse, filtering the remaining materials with nitrogen, washing, drying and crushing the obtained filter cake to obtain a solid-phase olefin functional polymer and a liquid-phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0070] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 70° C. and the pressure is 30 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0071] Example 4

[0072] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0073] (1) A low-carbon olefin is introduced into a tubular reactor and then the pressure is increased to a specified pressure, wherein the low-carbon olefin is propylene, and argon is first introduced before the low-carbon olefin is introduced. After reaching the reaction temperature and reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the tubular reactor, wherein the functional monomer is maleimide, and the solvent is benzene and xylene in a volume ratio of 1:1, and the mass ratio of the solvent to the functional monomer is 10:1. The reactor is irradiated with microwaves, wherein the microwaves are generated by a microwave generator, and the power of the microwave generator is 225 W, and a polymerization reaction occurs. The polymerization reaction temperature is 60° C., the pressure is 1 MPa, and the residence time is 6 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0074] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged low-carbon olefins to 1 MPa and returning to step (1) for reuse, filtering the remaining materials with argon gas, washing, drying and crushing the obtained filter cake to obtain a solid-phase olefin functional polymer and a liquid-phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0075] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 140° C. and the pressure is 90 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0076] Example 5

[0077] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0078] (1) A low-carbon olefin is introduced into a tubular reactor and then the pressure is increased to a specified pressure. The low-carbon olefin is propylene. Argon is first introduced before the low-carbon olefin is introduced. After reaching the reaction temperature and reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the tubular reactor. The functional monomer is maleic acid, and the solvent is ethylbenzene. The mass ratio of the solvent to the functional monomer is 30:1. The reactor is irradiated with microwaves. The microwaves are generated by a microwave generator. The power of the microwave generator is 175 W. A polymerization reaction occurs. The polymerization reaction temperature is 40° C., the pressure is 8 MPa, and the residence time is 0.5 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0079] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged low-carbon olefins to 8 MPa and returning to step (1) for reuse, filtering the remaining material with argon gas, washing, drying and crushing the obtained filter cake to obtain a solid-phase olefin functional polymer and a liquid-phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0080] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 100° C. and the pressure is 40 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0081] Example 6

[0082] This embodiment provides a method for synthesizing olefin functional polymers assisted by microwave irradiation, the method comprising the following steps:

[0083] (1) After a low-carbon olefin is introduced into a reactor and the pressure is increased to a specified pressure, the low-carbon olefin is ethylene, and nitrogen is first introduced before the low-carbon olefin is introduced. After reaching the reaction temperature and reaction pressure, a raw material liquid prepared by a functional monomer and a solvent is pumped into the reactor, the functional monomer is maleic anhydride, the solvent is butyl acetate and ethyl acetate in a volume ratio of 5:1, and the mass ratio of the solvent to the functional monomer is 15:1. The reactor is irradiated with microwaves, the microwaves are generated by a microwave generator, the power of the microwave generator is 250 W, and a polymerization reaction occurs. The polymerization reaction temperature is 70° C., the pressure is 3 MPa, and the residence time is 2 h. During the polymerization reaction, the low-carbon olefin is continuously introduced to maintain the pressure;

[0084] (2) cooling and depressurizing the system after the polymerization reaction in step (1), pressurizing the discharged low-carbon olefins to 3 MPa and returning to step (1) for reuse, filtering the remaining materials with nitrogen, washing, drying and crushing the obtained filter cake to obtain a solid-phase olefin functional polymer and a liquid-phase material, wherein the olefin functional polymer is in the form of microspherical particles;

[0085] (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 80° C. and the pressure is 10 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

[0086] Comparative Example 1

[0087] This comparative example provides a method for synthesizing an olefin functional polymer, which refers to the method in Example 1, except that: in step (1), microwave assisted initiation is not used, that is, a microwave generator is not used to irradiate the device, but a jacket is used to heat the reactor, and an initiator (benzoyl peroxide) and a functional monomer and a solvent are added to prepare a raw material liquid, and the molar ratio of the initiator to the functional monomer is 0.01:1; the reaction temperature is 80°C.

[0088] According to the tests of the raw material monomers and olefin functional polymers in the above embodiments and comparative examples, the functional monomer conversion rate, the yield of the olefin functional polymer and the anhydride value were calculated, and the particle size and weight average molecular weight of the polymer were tested and calculated. The relevant test methods are as follows:

[0089] (1) Acid anhydride value: The test method is titration. The sample is dissolved and digested, and then titrated with sodium hydroxide solution to test the acid anhydride content.

[0090] (2) D50 and D90 particle sizes: tested by laser particle size tester;

[0091] (3) Weight average molecular weight: measured by gel permeation chromatography (GPC).

[0092] The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095] As can be seen from Table 1, by adopting the method of the present invention to synthesize olefin functional polymers, the conversion rate of functional monomers can reach more than 90%, the yield of olefin functional polymers can also reach more than 90%, the anhydride value of the polymer is more than 72%, the particle size range is between 10 and 60 μm, and the weight-average molecular weight can reach more than 70,000. In the embodiment, the polymerization is assisted by microwave irradiation, which is easier to synthesize a relatively high molecular weight polymer compared with the traditional jacket heating and initiator-initiated polymerization in Comparative Example 1. At the same time, due to the fast microwave heating speed and selectivity for the heated material, the side reactions are less and the reaction selectivity is relatively improved.

[0096] It can be seen from the above embodiments and comparative examples that the method of the present invention realizes the same-chain alternating copolymerization of low-carbon gaseous olefins and functional monomers through the pressurized reaction of the two, and adopts a heterogeneous polymerization method to improve the monomer concentration and raw material utilization rate, synthesize solid olefin functional polymers, and have high reaction efficiency; the present invention adopts microwave irradiation to assist in initiating polymerization, has fewer side reactions, and the polymer is relatively pure, and it is easy to prepare high molecular weight polymers. The particle size of polymer microspheres is controllable and evenly distributed, the post-processing process is simple, and it is easy to separate and purify, the raw materials can be recycled, and the conversion rate of the raw materials and the product yield are improved; the method is simple to operate, the reaction conditions are mild, energy consumption is saved, the cost is low, and it is green and environmentally friendly.

[0097] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the method for synthesizing olefin functional polymers assisted by microwave irradiation, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for synthesizing olefin functional polymers assisted by microwave irradiation, characterized in that: The method comprises the following steps: (1) introducing a low carbon olefin into a reactor until the reaction pressure is reached, then adding a raw material solution prepared by a functional monomer and a solvent into the reactor, and then irradiating the reactor with microwaves to cause a polymerization reaction; (2) cooling and depressurizing the system after the polymerization reaction in step (1) to discharge the light olefins, returning the discharged light olefins to step (1) for reuse, and performing solid-liquid separation of the remaining materials to obtain a solid-phase olefin functional polymer and a liquid-phase material; (3) The liquid phase material obtained in step (2) is distilled, and the distilled fraction is returned to step (1) for reuse.

2. The method according to claim 1, characterized in that: The light olefin in step (1) includes any one of ethylene, propylene, butene or butadiene, or a combination of at least two thereof; Preferably, before the light olefin is introduced in step (1), the reactor is first evacuated and then replaced with a protective gas; Preferably, the reactor in step (1) comprises any one of a tank reactor, a tubular reactor, a microchannel reactor or a tower reactor; Preferably, the reaction pressure in step (1) is 0.1-10 MPa.

3. The method according to claim 1 or 2, characterized in that: The functional monomer in step (1) comprises any one of maleic anhydride, maleimide, maleic acid or methyl maleate, or a combination of at least two thereof; Preferably, the solvent in step (1) comprises any one or a combination of at least two of an organic alkanoate compound, an alkane compound or an aromatic compound; Preferably, the organic alkanoate compound comprises any one of 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 or isoamyl phenylacetate, or a combination of at least two thereof; Preferably, the alkane compound includes any one of cyclohexane, n-hexane or n-heptane, or a combination of at least two thereof; Preferably, the aromatic hydrocarbon compound includes any one of benzene, ethylbenzene or xylene, or a combination of at least two thereof; Preferably, in step (1), the mass ratio of the solvent to the functional monomer is (2-50):

1.

4. The method according to any one of claims 1 to 3, characterized in that The raw material liquid in step (1) is firstly removed from impurities and preheated before being added to the reactor; Preferably, the raw material liquid in step (1) is pressurized by a delivery pump and then pumped into the reactor at a uniform speed.

5. The method according to any one of claims 1 to 4, characterized in that The microwaves used in the microwave irradiation in step (1) are generated by a microwave generator; Preferably, the microwave generator is arranged outside the reactor; Preferably, the power of the microwave generator is 0.5-2000W.

6. The method according to any one of claims 1 to 5, characterized in that The polymerization reaction temperature in step (1) is 30 to 80° C. Preferably, the polymerization reaction pressure in step (1) is 0.1 to 10 MPa; Preferably, the microwave irradiation time in step (1) is 0.01 to 10 h; Preferably, during the polymerization reaction in step (1), light olefins are continuously introduced to maintain the pressure.

7. The method according to any one of claims 1 to 6, characterized in that During the cooling and pressure reduction process in step (2), the light olefins are discharged and replaced with a protective gas, wherein the protective gas includes nitrogen or argon; Preferably, the discharged low-carbon olefins in step (2) are pressurized and then returned to step (1) for reuse; Preferably, the pressure of the discharged light olefins after pressurization in step (2) is 0.1 to 10 MPa; Preferably, the solid-liquid separation in step (2) comprises filtration, preferably filter pressing.

8. The method according to any one of claims 1 to 7, characterized in that The solid phase olefin functional polymer in step (2) is in the form of microspherical particles with a particle size of 10 to 60 μm.

9. The method according to any one of claims 1 to 8, characterized in that The top temperature of the distillation tower in step (3) is 40-150° C. and the pressure is 0.1-101 kPa; Preferably, the top fraction after distillation in step (3) is returned to step (1) and reused to prepare the raw material liquid.

10. A method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) introducing a low-carbon olefin into a reactor, wherein the low-carbon olefin includes any one of ethylene, propylene, butene or butadiene or a combination of at least two thereof, and the reactor includes any one of a kettle reactor, a tubular reactor, a microchannel reactor or a tower reactor, and after the reaction pressure reaches 0.1 to 10 MPa, pumping a raw material liquid prepared from a functional monomer and a solvent into the reactor, wherein the functional monomer includes any one of maleic anhydride, maleimide, maleic acid or methyl maleate or a combination of at least two thereof, and the solvent includes organic alkanoates, alkane compounds or any one or a combination of at least two of aromatic hydrocarbon compounds, the mass ratio of the solvent to the functional monomer is (2-50):1, and then the reactor is subjected to microwave irradiation, the microwave used in the microwave irradiation is generated by a microwave generator, the power of the microwave generator is 0.5-2000W, the microwave irradiation time is 0.01-10h, a polymerization reaction occurs, the polymerization reaction temperature is 30-80°C, and is adjusted by the microwave power, the pressure is 0.1-10MPa, and low-carbon olefins are continuously introduced during the polymerization reaction to maintain the pressure; (2) cooling and depressurizing the system after the polymerization reaction in step (1) to discharge the light olefins, and returning the discharged light olefins to step (1) for reuse after pressurization, wherein the pressure of the light olefins after pressurization is 0.1 to 10 MPa, and the remaining materials are separated into solid and liquid, and the remaining materials are filtered by 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 solid-phase olefin functional polymer is a microspherical particle with a particle size of 10 to 60 μm; (3) The liquid phase material obtained in step (2) is distilled, and the top temperature of the distillation tower is 40-150° C. and the pressure is 0.1-101 kPa. The top fraction after distillation is returned to step (1) and reused for preparing the raw material liquid.

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