A method for efficiently preparing ethylene-maleic anhydride alternating copolymer

Abstract

The present invention provides the application of Lewis acid in preparing ethylene-maleic anhydride alternating copolymer. The present invention introduces a co-catalyst Lewis acid into a copolymerization catalytic system, greatly improves the copolymerization activity of ethylene and maleic anhydride, reduces the polymerization temperature, shortens the polymerization reaction time, significantly reduces ethylene pressure, reduces energy consumption, avoids high-pressure production equipment, improves the safety factor during production operation, and then improves monomer conversion, significantly improves production efficiency. Moreover, the present invention provides a preparation method, which is simple and easy, has mild process conditions, and is more suitable for industrial production and promotion and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing ethylene-maleic anhydride alternating copolymers, relates to the application of Lewis acid in preparing ethylene-maleic anhydride alternating copolymers and a method for preparing ethylene-maleic anhydride alternating copolymers, and particularly relates to the application of Lewis acid in preparing ethylene-maleic anhydride alternating copolymers and a method for efficiently preparing ethylene-maleic anhydride alternating copolymers. Background Art

[0002] Ethylene-maleic anhydride alternating copolymer (EAA) is a 1:1 alternating copolymer of ethylene and maleic anhydride, exhibiting high thermal stability and excellent mechanical properties. The polymer backbone contains a large number of highly reactive cyclic anhydride groups, which readily undergo chain extension reactions, such as reacting with amine groups in nylon chains to increase the molecular weight, mechanical properties, and freeze stability of nylon. This polymer is also widely used in adhesives and coatings applications, including laminating adhesives, multilayer packaging, hot melt adhesives, wood composites, and gap filling. Low molecular weight EAA copolymers can be melted or dissolved in water or solvents to meet the needs of many applications requiring liquid application.

[0003] Currently, commercialized ethylene-maleic anhydride copolymers are mostly obtained by grafting maleic anhydride onto polyethylene random copolymers. Representative brands include Dow's Fusabond M603 and Honeywell's AC573P. They are used as compatibilizers in wood-plastic composite processing and halogen-free flame-retardant wire and cable. They can also be used as tackifiers in vinyl coatings to enhance adhesion to materials such as aluminum foil, stainless steel, glass, PP, and PVC. This type of ethylene-maleic anhydride copolymer has a high market share, but suffers from a low grafting rate and ineffective chain extension. Ethylene-maleic anhydride alternating copolymers overcome these shortcomings. Currently, the production of ethylene-maleic anhydride alternating copolymers primarily involves high-temperature, high-ethylene pressure, and long-term polymerization (Polymer Science USSR 1983, 9, 2151-2160). These production conditions are extremely harsh and the production cost is high, which greatly limits their production scale and practical application.

[0004] Therefore, how to develop a synthesis method for ethylene-maleic anhydride alternating copolymers with mild reaction conditions and low cost to solve the above-mentioned problems existing in this field has become one of the focuses of widespread attention of many cutting-edge researchers in the field. Summary of the Invention

[0005] In light of this, the present invention aims to provide the use of a Lewis acid in the preparation of an ethylene-maleic anhydride alternating copolymer and a method for preparing the same, particularly a highly efficient method for preparing the same. The present invention significantly enhances the copolymerization activity of ethylene and maleic anhydride, shortens polymerization time, and reduces ethylene pressure by introducing a Lewis acid into the polymerization system. Furthermore, the preparation process is simple, operates under mild conditions, and exhibits strong controllability, facilitating industrial application and commercialization.

[0006] The present invention provides application of Lewis acid in preparing ethylene-maleic anhydride alternating copolymer.

[0007] Preferably, the ethylene-maleic anhydride alternating copolymer is prepared by copolymerizing maleic anhydride monomer with ethylene;

[0008] The molar ratio of the Lewis acid to maleic anhydride is (0.1-90):100;

[0009] The Lewis acid includes one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihalogenated boron, a trihalogenated aluminum, a zinc halide, and an iron halide.

[0010] Preferably, the application includes the combined application of Lewis acid and free radical initiator;

[0011] The Lewis acid has the functions of increasing the decomposition rate of the free radical initiator and improving the life of the free radical initiator;

[0012] The application is specifically an application for improving the preparation efficiency of ethylene-maleic anhydride alternating copolymers.

[0013] Preferably, the application specifically includes, under the combined action of Lewis acid and free radical initiator and under the condition of anhydrous and oxygen-free;

[0014] The free radical initiator includes an organic peroxide and / or an azo compound;

[0015] The molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100;

[0016] The Lewis acid acts as a co-catalyst.

[0017] Preferably, the Lewis acid specifically includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, triphenylboron, tris(p-fluorophenyl)boron, tris(o-fluorophenyl)boron, tris(2,6-difluorophenyl)boron, tris(3,5-trifluoromethylphenyl)boron, tris(pentafluorophenyl)aluminum, triphenylaluminum, tris(pentafluorophenyl)gallium and di(pentafluorophenyl)zinc;

[0018] The free radical initiator specifically includes one or more of dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxy-2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate and tert-amyl peroxybenzoate;

[0019] The ethylene-maleic anhydride alternating copolymer is an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:1.

[0020] The present invention provides a method for preparing an ethylene-maleic anhydride alternating copolymer, comprising the following steps:

[0021] Under the action of Lewis acid and free radical initiator, maleic anhydride monomer and ethylene are copolymerized in a reaction medium under anhydrous and oxygen-free conditions to obtain an ethylene-maleic anhydride alternating copolymer.

[0022] Preferably, the reaction medium comprises one or more of an alkane solvent, an aromatic solvent, a halogenated alkane solvent and a halogenated aromatic solvent;

[0023] The concentration of the maleic anhydride monomer in the reaction medium is 0.1 to 5.0 mol / L;

[0024] The pressure of the ethylene is 1.0 to 300.0 bar.

[0025] Preferably, the molar ratio of the Lewis acid to maleic anhydride is (0.1-90):100;

[0026] The Lewis acid comprises one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron compound, a trihaloaluminum compound, a zinc halide, and an iron halide;

[0027] The reaction medium includes one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene and decahydronaphthalene.

[0028] Preferably, the free radical initiator comprises an organic peroxide and / or an azo compound;

[0029] The molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100;

[0030] The ethylene-maleic anhydride alternating copolymer is an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:1.

[0031] Preferably, the copolymerization reaction time is 0.1 to 24 hours;

[0032] The temperature of the copolymerization reaction is 30 to 160° C.

[0033] The copolymerization reaction further includes filtering and / or drying steps.

[0034] The present invention provides the use of a Lewis acid in the preparation of an ethylene-maleic anhydride alternating copolymer. Compared to the prior art, the present invention addresses the extremely harsh production conditions in the actual preparation of existing ethylene-maleic anhydride alternating copolymers, which typically require polymerization at 70°C and 300 psi ethylene pressure for 15 to 18 hours to achieve a high conversion rate. This leads to high ethylene pressure, long reaction cycles, and high equipment requirements, resulting in high production costs. The present invention creatively applies a Lewis acid to the copolymerization of ethylene and maleic anhydride to prepare an ethylene-maleic anhydride alternating copolymer. During the reaction, the Lewis acid can accelerate the decomposition rate of the free radical initiator, increase the free radical content in the reaction system, and simultaneously reduce the occurrence of free radical quenching, thereby improving the stability of the free radicals and extending the life of the free radical initiator. The existing method for preparing ethylene-maleic anhydride alternating copolymers by copolymerizing ethylene with maleic anhydride requires the use of a free radical initiator to initiate polymerization. The copolymers of the present invention utilize a Lewis acid in combination with a free radical initiator, eliminating the issues that affect the effectiveness of the free radical initiator and the properties of the copolymers in similar applications. Furthermore, the Lewis acid significantly improves the reaction efficiency, significantly reducing production time and costs. Furthermore, the Lewis acid can activate the maleic anhydride monomer, making the double bonds of the activated maleic anhydride more electron-deficient and enhancing the monomer's polarization effect, making it easier to undergo alternating copolymerization with ethylene. Consequently, under the same conditions as existing preparation processes, ethylene-maleic anhydride copolymers can be prepared more efficiently, improving production efficiency and reducing costs.

[0035] Experimental results show that the introduction of a Lewis acid co-catalyst into the copolymerization catalytic system significantly enhances the copolymerization activity of ethylene and maleic anhydride, reduces polymerization temperature, shortens polymerization reaction time, reduces energy consumption, increases monomer conversion, and significantly improves production efficiency. Furthermore, the preparation method is simple and easy to implement, with mild process conditions, making it more suitable for industrial production and widespread application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1This is a hydrogen nuclear magnetic resonance spectrum of the ethylene-maleic anhydride alternating copolymer prepared in Example 2 of the present invention;

[0037] Figure 2 This is the DSC curve of the ethylene-maleic anhydride alternating copolymer prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0038] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than for limiting the claims of the invention.

[0039] All raw materials of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0040] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses analytically pure materials or materials with conventional purity requirements in the field of preparation of ethylene-maleic anhydride alternating copolymers.

[0041] The present invention has no particular limitation on the expression of the substituents, and all expressions familiar to those skilled in the art are adopted. Based on common sense, those skilled in the art can correctly understand the meaning of the substituents according to the expressions.

[0042] All raw materials of the present invention, their brands or abbreviations are conventional brands or abbreviations in the field. Each brand and abbreviation is clear and unambiguous in the field of its relevant use. Those skilled in the art can purchase them from commercial sources or prepare them by conventional methods based on the brand, abbreviation and corresponding use.

[0043] The present invention provides application of Lewis acid in preparing ethylene-maleic anhydride alternating copolymer.

[0044] In the present invention, the ethylene-maleic anhydride alternating copolymer is preferably prepared by copolymerizing maleic anhydride monomer with ethylene.

[0045] In the present invention, the molar ratio of the Lewis acid to maleic anhydride is preferably (0.1-90):100, more preferably (0.1-50):100, more preferably (0.5-10):100, and more preferably (1-5):100.

[0046] In the present invention, the Lewis acid preferably includes one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron, a trihaloaluminum, a zinc halide and an iron halide, and more preferably an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron, a trihaloaluminum, a zinc halide or an iron halide.

[0047] In the present invention, the application preferably includes the combined application of a Lewis acid and a free radical initiator. Specifically, the Lewis acid of the present invention is preferably used as a co-catalyst.

[0048] In the present invention, the functions of the Lewis acid preferably include increasing the decomposition rate of the free radical initiator and improving the life of the free radical initiator.

[0049] In the present invention, the application is preferably to improve the preparation efficiency of ethylene-maleic anhydride alternating copolymers.

[0050] In the present invention, the application preferably includes the combined action of Lewis acid and free radical initiator under anhydrous and oxygen-free conditions.

[0051] In the present invention, the free radical initiator preferably includes an organic peroxide and / or an azo compound, more preferably an organic peroxide or an azo compound.

[0052] In the present invention, the molar ratio of the free radical initiator to maleic anhydride is preferably (0.1-90):100, more preferably (0.5-60):100, more preferably (1-30):100, more preferably (1-10):100, more preferably (1-5):100.

[0053] In the present invention, the Lewis acid specifically preferably includes trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, triphenylboron, tris(p-fluorophenyl)boron, tris(o-fluorophenyl)boron, tris(2,6-difluorophenyl)boron, tris(3,5-trifluoromethylphenyl)boron, tris(pentafluorophenyl)aluminum, triphenylaluminum, tris(pentafluorophenyl)gallium and di(pentafluorophenyl)boron. The present invention further comprises one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, triphenylboron, tris(p-fluorophenyl)boron, tris(o-fluorophenyl)boron, tris(2,6-difluorophenyl)boron, tris(3,5-trifluoromethylphenyl)boron, tris(pentafluorophenyl)aluminum, triphenylaluminum, tris(pentafluorophenyl)gallium or di(pentafluorophenyl)zinc.

[0054] In the present invention, the free radical initiator specifically preferably includes one or more of dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxide 2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxide)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate and tert-amyl peroxybenzoate, and more preferably dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxide 2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate or tert-amyl peroxybenzoate.

[0055] In the present invention, the ethylene-maleic anhydride alternating copolymer is preferably an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:1.

[0056] The present invention provides a method for preparing an ethylene-maleic anhydride alternating copolymer, comprising the following steps:

[0057] Under the action of Lewis acid and free radical initiator, maleic anhydride monomer and ethylene are copolymerized in a reaction medium under anhydrous and oxygen-free conditions to obtain an ethylene-maleic anhydride alternating copolymer.

[0058] In the present invention, the reaction medium preferably includes one or more of an alkane solvent, an aromatic hydrocarbon solvent, a halogenated alkane solvent and a halogenated aromatic hydrocarbon solvent, more preferably an alkane solvent, an aromatic hydrocarbon solvent, a halogenated alkane solvent or a halogenated aromatic hydrocarbon solvent.

[0059] In the present invention, the concentration of the maleic anhydride monomer in the reaction medium is preferably 0.1 to 5.0 mol / L, more preferably 1.0 to 4.0 mol / L, and even more preferably 2.0 to 3.0 mol / L.

[0060] In the present invention, the pressure of ethylene is 1.0 to 300.0 bar, more preferably 2.0 to 200.0 bar, more preferably 4.0 to 150.0 bar, more preferably 6.0 to 100.0 bar, more preferably 10.0 to 50.0 bar.

[0061] In the present invention, the molar ratio of the Lewis acid to maleic anhydride is preferably (0.1-90):100, more preferably (0.1-50):100, more preferably (0.5-10):100, and more preferably (1-5):100.

[0062] In the present invention, the Lewis acid preferably includes one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron, a trihaloaluminum, a zinc halide and an iron halide, and more preferably an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron, a trihaloaluminum, a zinc halide or an iron halide.

[0063] In the present invention, the reaction medium preferably includes one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene and decahydronaphthalene, more preferably pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene or decahydronaphthalene.

[0064] In the present invention, the free radical initiator preferably includes an organic peroxide and / or an azo compound, more preferably an organic peroxide or an azo compound.

[0065] In the present invention, the molar ratio of the free radical initiator to maleic anhydride is preferably (0.1-90):100, more preferably (0.5-60):100, more preferably (1-30):100, more preferably (1-10):100, more preferably (1-5):100.

[0066] In the present invention, the ethylene-maleic anhydride alternating copolymer is preferably an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:1.

[0067] In the present invention, the copolymerization reaction time is preferably 0.1 to 24 hours, more preferably 1 to 20 hours, more preferably 2 to 12 hours, and more preferably 3 to 6 hours.

[0068] In the present invention, the temperature of the copolymerization reaction is preferably 30 to 160°C, more preferably 50 to 140°C, more preferably 60 to 120°C, and more preferably 60 to 100°C.

[0069] In the present invention, the copolymerization reaction preferably further includes a filtration and / or drying step, more preferably a filtration or drying step.

[0070] In the present invention, the number average molecular weight of the ethylene-maleic anhydride alternating copolymer is preferably greater than or equal to 16,000.

[0071] The present invention is to better complete and refine the overall technical solution, further improve the copolymerization activity of ethylene and maleic anhydride, reduce the polymerization temperature, shorten the reaction time, reduce energy consumption, and better improve the monomer conversion rate and production efficiency. The efficient preparation method of the above-mentioned ethylene-maleic anhydride alternating copolymer can specifically include the following steps:

[0072] The preparation method of ethylene-maleic anhydride alternating copolymer comprises the following steps:

[0073] Under the action of Lewis acid, free radical initiator and anhydrous and oxygen-free conditions, maleic anhydride monomer and ethylene are copolymerized in a reaction medium to obtain an ethylene-maleic anhydride alternating copolymer.

[0074] Specifically, the Lewis acid includes one or more of organoaluminum, organoboron, organogallium, organozinc, trihaloboron, trihaloaluminum, zinc halide, iron halide, and the like.

[0075] Specifically, the Lewis acid includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, triphenylboron, tris(p-fluorophenyl)boron, tris(o-fluorophenyl)boron, tris(2,6-difluorophenyl)boron, tris(3,5-trifluoromethylphenyl)boron, tris(pentafluorophenyl)aluminum, triphenylaluminum, tris(pentafluorophenyl)gallium, and di(pentafluorophenyl)zinc.

[0076] Specifically, the amount of the Lewis acid used is 0.1% to 90.0% of the molar amount of maleic anhydride.

[0077] Specifically, the free radical initiator includes organic peroxides and / or azo compounds.

[0078] Specifically, the free radical initiator includes one or more of dibenzoyl peroxide (BPO), azobisisobutyl cyanide (AIBN), tert-butyl peroxy-2-ethylhexanoate (TBPO), lauroyl peroxide (LPO), 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide (DCP), tert-amyl peroxyacetate (TAPA), and tert-amyl peroxybenzoate (TAPB).

[0079] Specifically, the amount of the free radical initiator is 0.1% to 90.0% of the molar amount of maleic anhydride.

[0080] Specifically, the reaction medium includes organic solvents such as alkanes, aromatic hydrocarbons, halogenated alkanes, and halogenated aromatic hydrocarbons.

[0081] Specifically, the organic solvent is one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene, and decahydronaphthalene.

[0082] Specifically, the concentration of the maleic anhydride monomer is 0.1 to 5.0 mol / L.

[0083] Specifically, the ethylene pressure is 1.0 to 300.0 bar.

[0084] Specifically, the reaction time is 0.1 to 24 hours.

[0085] Specifically, the reaction temperature is 30-160°C.

[0086] Specifically, the copolymerization further includes filtering and / or drying steps.

[0087] Further:

[0088] The preparation method of the above-mentioned ethylene-maleic anhydride alternating copolymer can be the following steps:

[0089] Under anhydrous and oxygen-free conditions, maleic anhydride is added to a reaction vessel containing an organic solvent reaction medium and stirred thoroughly, and then a Lewis acid and a free radical initiator are added. The mixture is then reacted at 30-160° C. for 0.1-24 hours to obtain a suspension of ethylene-maleic anhydride copolymer. The suspension is then centrifuged or filtered and vacuum dried to obtain a white solid product of the ethylene-maleic anhydride copolymer.

[0090] Specifically, the Lewis acid preferably includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, tris(pentafluorophenyl)aluminum, tris(pentafluorophenyl)gallium, and di(pentafluorophenyl)zinc, preferably one or more of triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, tris(pentafluorophenyl)boron, tris(pentafluorophenyl)aluminum, and di(pentafluorophenyl)zinc.

[0091] Specifically, the organic aluminum of the present invention preferably includes trialkylaluminum of C2 to C20 alkanes, that is, trialkylaluminum substituted with C2 to C20 alkanes, more preferably trialkylaluminum of C2 to C17 alkanes, more preferably trialkylaluminum of C2 to C15 alkanes, more preferably trialkylaluminum of C2 to C12 alkanes, and more preferably trialkylaluminum of C2 to C8 alkanes.

[0092] Specifically, the organic boron of the present invention preferably includes trialkylborane of C2-C20 paraffin, that is, trialkylborane substituted by C2-C20 paraffin; and also includes triarylborane of C6-C12.

[0093] Specifically, the organic gallium of the present invention preferably includes trialkylgallium of C2-C20 alkanes, that is, trialkylgallium substituted by C2-C20 alkanes, more preferably trialkylgallium of C2-C17 alkanes, more preferably trialkylgallium of C2-C15 alkanes, more preferably trialkylgallium of C2-C12 alkanes, and more preferably trialkylgallium of C2-C8 alkanes.

[0094] Specifically, the organoaluminum of the present invention preferably includes dialkylzinc of C2-C20 alkanes, that is, dialkylzinc substituted with C2-C20 alkanes, more preferably dialkylzinc of C2-C17 alkanes, more preferably dialkylzinc of C2-C15 alkanes, more preferably dialkylzinc of C2-C12 alkanes, and more preferably dialkylzinc of C2-C8 alkanes.

[0095] Specifically, the molar ratio of the Lewis acid to the maleic anhydride monomer of the present invention is preferably 0.1% to 90.0%, more preferably 0.1% to 50.0%, more preferably 0.5% to 10.0%, more preferably 1% to 10.0%, more preferably 1% to 5.0%.

[0096] Specifically, the free radical initiator of the present invention preferably includes an organic peroxide and / or an azo compound, more preferably an organic peroxide or an azo compound. The free radical initiator is preferably one or more of dibenzoyl peroxide (BPO), azobisisobutyl cyanide (AIBN), tert-butyl peroxy-2-ethylhexanoate (TBPO), lauroyl peroxide (LPO), 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide (DCP), tert-amyl peroxyacetate (TAPA), and tert-amyl peroxybenzoate (TAPB).

[0097] Specifically, the reaction medium of the present invention preferably includes an organic solvent. Specifically, the organic solvent preferably includes one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene, and decahydronaphthalene.

[0098] Specifically, the molar ratio of the free radical initiator to the maleic anhydride monomer of the present invention is preferably 0.1% to 90.0%, more preferably 0.5% to 60.0%, more preferably 1% to 30.0%, more preferably 1% to 10.0%, and more preferably 1% to 5.0%.

[0099] Specifically, the ethylene pressure of the copolymerization of the present invention is preferably 1.0 to 300.0 bar, more preferably 2.0 to 200.0 bar, more preferably 4.0 to 150.0 bar, more preferably 6.0 to 100.0 bar, and more preferably 10.0 to 50.0 bar.

[0100] Specifically, the copolymerization temperature of the present invention is preferably 30 to 160° C., more preferably 50 to 140° C., more preferably 60 to 120° C., and more preferably 60 to 100° C. The copolymerization temperature of the present invention is associated with the copolymerization time. The higher the copolymerization temperature, the shorter the time required. Specifically, the copolymerization temperature can be 40 to 130° C.

[0101] Specifically, the copolymerization time of the present invention is preferably 0.1 to 24 hours, more preferably 1 to 20 hours, more preferably 2 to 12 hours, and more preferably 3 to 6 hours.

[0102] Specifically, the present invention completes and refines the preparation process, improves the polymerization rate and monomer conversion rate, and is more conducive to subsequent applications. After the copolymerization, the process preferably further includes a filtration and / or drying step, more preferably a filtration or drying step.

[0103] The ethylene-maleic anhydride alternating copolymer prepared by the preparation method of the ethylene-maleic anhydride copolymer provided by the above steps of the present invention has a wide range of application prospects in aspects such as coatings, adhesives, and nylon reinforcing agents. In the copolymerization system of the present invention, Lewis acid and free radical initiator catalysis maleic anhydride and ethylene are utilized to alternately copolymerize to generate ethylene-maleic anhydride alternating copolymer. Moreover, the polyreaction can be carried out within a wide temperature range. The copolymerization method provided by the present invention effectively overcomes the temperature and ethylene pressure limitations of preparing ethylene-maleic anhydride copolymer, overcomes the excessively high polymerization temperature and ethylene pressure and the long reaction time cycle of utilizing prior art means to prepare ethylene-maleic anhydride copolymer, and has the characteristics of simple process, easy operation, strong process controllability, mild conditions, lower cost, environmental friendliness, and the simple and easy post-processing process of the copolymer, which is conducive to industrial application and commercial promotion.

[0104] The present invention provides the application of Lewis acid in the preparation of ethylene-maleic anhydride alternating copolymers and an efficient preparation method for ethylene-maleic anhydride alternating copolymers. The present invention applies Lewis acid to the copolymerization of ethylene and maleic anhydride to prepare ethylene-maleic anhydride alternating copolymers. During the reaction process, Lewis acid can accelerate the decomposition rate of the free radical initiator, increase the content of free radicals in the reaction system, and simultaneously reduce the occurrence of free radical quenching, thereby improving the stability of the free radicals and extending the life of the free radical initiator. Based on the existing route for preparing ethylene-maleic anhydride alternating products by copolymerization of ethylene and maleic anhydride, a free radical initiator must be used to initiate the polymerization. The copolymer of the present invention uses Lewis acid in combination with a free radical initiator, which not only does not affect the effect of the free radical initiator and the properties of the copolymer in similar applications, but also can significantly improve the reaction effect, greatly reducing production time and production costs. At the same time, the Lewis acid can also activate maleic anhydride monomers. After activation, the double bonds of maleic anhydride are more electron-deficient, the polarization effect of the monomer is enhanced, and it is easier to undergo alternating copolymerization with ethylene. Therefore, under the same conditions as the existing preparation process, ethylene-maleic anhydride copolymers can be prepared more efficiently, thereby improving the production efficiency of ethylene-maleic anhydride copolymers and reducing their costs.

[0105] Experimental results demonstrate that the introduction of a Lewis acid co-catalyst into the copolymerization catalytic system significantly enhances the copolymerization activity of ethylene and maleic anhydride, reduces polymerization temperature, shortens polymerization reaction time, reduces energy consumption, increases monomer conversion, and significantly improves production efficiency. Furthermore, the preparation method is simple and easy to implement, with mild process conditions, making it more suitable for industrial production and widespread application.

[0106] To further illustrate the present invention, the use of a Lewis acid in the preparation of an ethylene-maleic anhydride alternating copolymer and a method for preparing an ethylene-maleic anhydride alternating copolymer provided by the present invention are described in detail below with reference to the following examples. However, it should be understood that these examples are implemented based on the technical solutions of the present invention, and detailed implementation methods and specific operating procedures are provided only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. The scope of protection of the present invention is not limited to the following examples.

[0107] The present invention has no particular limitation on the sources of the raw materials in the following examples, and the raw materials can be prepared by methods well known to those skilled in the art or purchased from the market.

[0108] Performance testing methods and standards

[0109] The molecular weight of the polymer was determined by gel chromatography at room temperature at 40°C using DMF as the mobile phase (containing 0.5 wt% N n Bu4Br), and standard polystyrene was used as the reference sample for testing.

[0110] The glass transition temperature of the polymer was measured using a differential scanning calorimeter (DSC) with a heating and cooling rate of 10°C / min and a scanning range of 25-300°C.

[0111] The polymer proton spectrum structure was determined using a Bruker AV500 nuclear magnetic resonance spectrometer. The test temperature was 25° C., and the deuterated reagent was deuterated acetone or deuterated dimethyl sulfoxide.

[0112] Example 1

[0113] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of Al(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for reaction for 3 hours, the mixture was precipitated in anhydrous methanol.

[0114] Polymerization product M n =42000, molecular weight distribution 1.33, polymer yield 68 g.

[0115] Example 2

[0116] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for 4 hours, the mixture was precipitated in anhydrous methanol.

[0117] Polymerization product M n =37000, molecular weight distribution 1.32, polymer yield 94 g.

[0118] The ethylene-maleic anhydride alternating copolymer prepared in Example 2 of the present invention was characterized.

[0119] See also Figure 1 , Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the ethylene-maleic anhydride alternating copolymer prepared in Example 2 of the present invention.

[0120] See also Figure 2 , Figure 2 This is the DSC curve of the ethylene-maleic anhydride alternating copolymer prepared in Example 2 of the present invention.

[0121] Example 3

[0122] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 10 mmol of AlEt3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for 6 hours, the mixture was precipitated in anhydrous methanol.

[0123] Polymerization product M n =18000, molecular weight distribution 1.41, polymer yield 35 g.

[0124] Example 4

[0125] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 10 mmol of Al i Bu3, 10mmol AIBN and 2L toluene, replace the gas in the bottle with ethylene, maintain the ethylene pressure at 6 bar, place it in a 40℃ oil bath to react for 4 hours, and then precipitate it in anhydrous methanol.

[0126] Polymerization product M n =17300, molecular weight distribution 1.54, polymer yield 16 g.

[0127] Example 5

[0128] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 10 mmol of AlCl2Et, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After placing it in a 60°C oil bath for 4 hours, it was precipitated in anhydrous methanol.

[0129] Polymerization product M n =16000, molecular weight distribution 1.55, polymer yield 17 g.

[0130] Example 6

[0131] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of Zn(C6F5)2, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for 4 hours, the mixture was precipitated in anhydrous methanol.

[0132] Polymerization product M n =39000, molecular weight distribution 1.25, polymer yield 23 g.

[0133] Example 7

[0134] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 1 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for reaction for 2 hours, the mixture was precipitated in anhydrous methanol.

[0135] Polymerization product M n =33000, molecular weight distribution 1.45, polymer yield 58 g.

[0136] Example 8

[0137] Under the protection of high-purity nitrogen, 2 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for reaction for 2 hours, the mixture was precipitated in anhydrous methanol.

[0138] Polymerization product M n =36000, molecular weight distribution 1.37, polymer yield 57 g.

[0139] Example 9

[0140] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 50 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After being placed in a 60°C oil bath for reaction for 1 hour, the mixture was precipitated in anhydrous methanol.

[0141] Polymerization product M n =36000, molecular weight distribution 1.3, polymer yield 93 g.

[0142] Example 10

[0143] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 10 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 60°C oil bath for reaction for 2 hours, the mixture was precipitated in anhydrous methanol.

[0144] Polymerization product M n =36800, molecular weight distribution 1.22, polymer yield 113 g.

[0145] Example 11

[0146] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 50 mmol of B(C6F5)3, 5 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 50 bar. After being placed in a 60°C oil bath for 1 hour, the mixture was precipitated in anhydrous methanol.

[0147] Polymerization product M n =37000, molecular weight distribution 1.27, polymer yield 148 g.

[0148] Example 12

[0149] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 25 mmol of B(C6F5)3, 20 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After being placed in a 100°C oil bath for 2 hours, the mixture was precipitated in anhydrous methanol.

[0150] Polymerization product M n =35000, molecular weight distribution 1.28, polymer yield 70 g.

[0151] Example 13

[0152] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 200 mL of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 40°C oil bath for 2 hours, the mixture was precipitated in anhydrous methanol.

[0153] Polymerization product M n =45700, molecular weight distribution 1.33, polymer yield 10 g.

[0154] Example 14

[0155] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 50°C oil bath for 3 hours, the mixture was precipitated in anhydrous methanol.

[0156] Polymerization product M n =42400, molecular weight distribution 1.31, polymer yield 24 g.

[0157] Example 15

[0158] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in a 70°C oil bath for 2 hours, the mixture was precipitated in anhydrous methanol.

[0159] Polymerization product M n =32400, molecular weight distribution 1.28, polymer yield 63 g.

[0160] Example 16

[0161] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After being placed in an 80°C oil bath for reaction for 2 hours, the mixture was precipitated in anhydrous methanol.

[0162] Polymerization product M n =27000, molecular weight distribution 1.23, polymer yield 45 g.

[0163] Example 17

[0164] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 2 bar. After being placed in a 60°C oil bath for 2 hours, the mixture was precipitated in anhydrous methanol.

[0165] Polymerization product M n =20700, molecular weight distribution 1.27, polymer yield 14 g.

[0166] Example 18

[0167] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 4 bar. After being placed in a 60°C oil bath for 2 hours, the mixture was precipitated in anhydrous methanol.

[0168] Polymerization product M n =31200, molecular weight distribution 1.27, polymer yield 36 g.

[0169] Example 19

[0170] Under the protection of high-purity nitrogen, 1 mol of maleic anhydride monomer, 20 mmol of B(C6F5)3, 10 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 20 bar. After being placed in a 60°C oil bath for reaction for 2 hours, the mixture was precipitated in anhydrous methanol.

[0171] Polymerization product M n =66000, molecular weight distribution 1.53, polymer yield 131 g.

[0172] Comparative Example 1

[0173] Under the protection of high-purity nitrogen, 1.5 mol of maleic anhydride monomer, 20 mmol of AIBN and 2 L of toluene were added to the polymerization bottle, and the gas in the bottle was replaced with ethylene. The ethylene pressure was maintained at 10 bar. After reacting in a 100°C oil bath for 2 hours, the product was precipitated in anhydrous methanol.

[0174] Polymerization product M n =6000, molecular weight distribution 1.31, polymer yield 4 g.

[0175] The present invention introduces Lewis acid into the ethylene and maleic anhydride copolymerization catalytic system to reduce the activation energy of the ethylene and maleic anhydride copolymerization reaction, thereby significantly reducing the ethylene pressure, shortening the polymerization reaction time, improving production efficiency, avoiding high-pressure production equipment, and improving the safety factor during production operation.

[0176] The above describes in detail the use of Lewis acids in the preparation of ethylene-maleic anhydride alternating copolymers and an efficient method for preparing ethylene-maleic anhydride alternating copolymers provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the methods and core concepts of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including making and using any device or system, and implementing any combined method. It should be noted that, without departing from the principles of the present invention, a person skilled in the art may make several improvements and modifications to the present invention, and such improvements and modifications fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that may be conceived by a person skilled in the art. If these other embodiments have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims, then these other embodiments are also intended to be included within the scope of the claims.

Claims

1. Application of Lewis acid in the preparation of ethylene-maleic anhydride alternating copolymers; The application specifically includes the following steps: under the combined action of Lewis acid and free radical initiator and under the condition of anhydrous and oxygen-free; The Lewis acid comprises one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron compound, a trihaloaluminum compound, a zinc halide, and an iron halide; The free radical initiator includes organic peroxides and / or azo compounds.

2. The use according to claim 1, characterized in that The ethylene-maleic anhydride alternating copolymer is prepared by copolymerizing maleic anhydride monomer and ethylene; The molar ratio of the Lewis acid to maleic anhydride is (0.1-90):

100.

3. The use according to claim 1, characterized in that The Lewis acid has the functions of increasing the decomposition rate of the free radical initiator and improving the life of the free radical initiator; The application is specifically an application for improving the preparation efficiency of ethylene-maleic anhydride alternating copolymers.

4. The use according to claim 3, characterized in that The molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100; The Lewis acid acts as a co-catalyst.

5. The use according to claim 3, characterized in that The Lewis acid specifically includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, ethylaluminum dichloride, diethylaluminum chloride, boron trihalide, aluminum trihalide, gallium trihalide, zinc dihalide, tris(pentafluorophenyl)boron, triphenylboron, tris(p-fluorophenyl)boron, tris(o-fluorophenyl)boron, tris(2,6-difluorophenyl)boron, tris(3,5-trifluoromethylphenyl)boron, tris(pentafluorophenyl)aluminum, triphenylaluminum, tris(pentafluorophenyl)gallium and di(pentafluorophenyl)zinc; The free radical initiator specifically includes one or more of dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxy-2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amylperoxy)cycloalkane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate and tert-amyl peroxybenzoate; The ethylene-maleic anhydride alternating copolymer is an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:

1.

6. A method for preparing an ethylene-maleic anhydride alternating copolymer, characterized in that: The following steps are involved: Under the action of Lewis acid and free radical initiator, maleic anhydride monomer and ethylene are copolymerized in a reaction medium under anhydrous and oxygen-free conditions to obtain an ethylene-maleic anhydride alternating copolymer; The Lewis acid comprises one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron compound, a trihaloaluminum compound, a zinc halide, and an iron halide; The free radical initiator includes organic peroxides and / or azo compounds.

7. The preparation method according to claim 6, characterized in that The reaction medium comprises one or more of an alkane solvent, an aromatic hydrocarbon solvent, a halogenated alkane solvent and a halogenated aromatic hydrocarbon solvent; The concentration of the maleic anhydride monomer in the reaction medium is 0.1 to 5.0 mol / L; The pressure of the ethylene is 1.0 to 300.0 bar.

8. The preparation method according to claim 6, characterized in that The molar ratio of the Lewis acid to maleic anhydride is (0.1-90):100; The Lewis acid comprises one or more of an organoaluminum compound, an organoboron compound, an organogallium compound, an organozinc compound, a trihaloboron compound, a trihaloaluminum compound, a zinc halide, and an iron halide; The reaction medium includes one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene and decahydronaphthalene.

9. The preparation method according to claim 6, characterized in that The free radical initiator includes an organic peroxide and / or an azo compound; The molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100; The ethylene-maleic anhydride alternating copolymer is an alternating copolymer with a copolymerization ratio of ethylene to maleic anhydride of 1:

1.

10. The preparation method according to claim 6, characterized in that The copolymerization reaction time is 0.1 to 24 hours; The temperature of the copolymerization reaction is 30-160°C; The copolymerization reaction further includes filtering and / or drying steps.

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