阅读说明：本技术 一种采用界面-固相缩聚制备芳香聚酰胺的方法 (Method for preparing aromatic polyamide by adopting interfacial-solid phase polycondensation ) 是由 曹凯凯 刘玉峰 伍威 李忠良 刘含茂 曹卓 袁锋 甘顺昌 程海涛 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种芳香聚酰胺的制备方法,包含以下步骤：(1)界面缩聚：将芳香二酰氯、芳香二胺、有机溶剂和含有缚酸剂的水溶液加入到反应器中,在转速为200～1000rpm的强烈搅拌下混合反应,反应完成后,将反应产物水洗、分离、干燥,得到低分子量的预聚物；(2)固相缩聚：将低分子量预聚物在惰性气体保护下或者真空下继续反应,得到芳香聚酰胺。本发明采用界面缩聚-固相缩聚,通过固相缩聚提高了聚酰胺的分子量(比浓对数粘度),克服了传统界面缩聚的不足,通过界面缩聚得到的预聚物和通过固相缩聚的最终产物均为纯净的固体颗粒或粉末,无杂质,可用于多种用途,克服了低温溶液缩聚的杂质影响性能、储存运输不便的不足。(The invention discloses a preparation method of aromatic polyamide, which comprises the following steps: (1) interfacial polycondensation: adding aromatic diacid chloride, aromatic diamine, an organic solvent and an aqueous solution containing an acid-binding agent into a reactor, mixing and reacting under strong stirring at the rotating speed of 200-1000 rpm, and after the reaction is finished, washing, separating and drying a reaction product to obtain a low-molecular-weight prepolymer; (2) solid phase polycondensation: and (3) continuously reacting the low molecular weight prepolymer under the protection of inert gas or vacuum to obtain the aromatic polyamide. The invention adopts interfacial polycondensation-solid phase polycondensation, improves the molecular weight (inherent viscosity) of polyamide through solid phase polycondensation, overcomes the defects of the traditional interfacial polycondensation, obtains the prepolymer through the interfacial polycondensation and the final product through the solid phase polycondensation, are pure solid particles or powder without impurities, can be used for multiple purposes, and overcomes the defects of the impurity influence performance and the inconvenient storage and transportation of low-temperature solution polycondensation.)

1. A process for preparing aromatic polyamides by interfacial-solid phase polycondensation, comprising the steps of:

(1) interfacial polycondensation: under the protection of inert gas, adding aromatic diacid chloride, aromatic diamine, an organic solvent and an aqueous solution containing an acid-binding agent into a reactor, reacting under strong stirring at the rotating speed of 200-1000 rpm, and after the reaction is finished, washing, separating and drying a reaction product to obtain a prepolymer;

(2) solid phase polycondensation: and (3) continuously reacting the prepolymer under the protection of inert gas or vacuum to obtain the aromatic polyamide.

2. The method according to claim 1, wherein in the step (1), the reaction temperature is-40 to 100 ℃ and the reaction time is 10s to 30 min.

3. The method according to claim 2, wherein in the step (1), the reaction temperature is-15 to 40 ℃ and the reaction time is 1 to 10 min.

4. The method according to claim 1, wherein in the step (2), the carrier gas flow of the inert gas is 10-500 mL/min, the reaction temperature is 200-350 ℃, and the reaction time is 30-72 h;

or, the reaction is carried out under the vacuum pressure of 100Pa or less, the reaction temperature is 100-350 ℃, and the reaction time is 1-24 h.

5. The method of claim 1, wherein the aromatic diacid chloride and the aromatic diamine are each present at a concentration of 0.01 to 2 mol/L; and the molar ratio of the aromatic diacid chloride to the aromatic diamine is 0.8-1.2.

6. The method of claim 5, wherein the aromatic diacid chloride and the aromatic diamine are each present at a concentration of 0.2 to 1 mol/L; and the molar ratio of the aromatic diacid chloride to the aromatic diamine is 0.98-1.02.

7. The process of claim 1 wherein said aromatic diacid chloride has the formula ClOC-a-COCl or ClOC-a-Y-a' -COCl; wherein A and A' are aromatic carbon cores or bivalent non-reactive groups for substituting the aromatic carbon cores, and the non-reactive groups comprise halogens, low-carbon alkyl, phenyl, acyl, acetyl epoxy groups, nitro and sulfonic acid groups; y is an ether (-O-), thioether (-S-), carbonyl (-CO-), sulfo (-SO-) group connecting two aromatic carbon nuclei and not reacting with an acid chloride or an amine₂-), an N-substituted imino group, an amide, an N-substituted amide, or an alkyl ester, and two acid chloride groups are attached to carbon atoms not adjacent to the aromatic carbon core.

8. The method of claim 7, wherein the aromatic diacid chloride is selected from the group consisting of terephthaloyl chloride, isophthaloyl chloride, 1, 4-naphthaloyl chloride, 2, 6-naphthaloyl chloride, 4' -biphenyloyl chloride, 5-chloroisophthaloyl chloride, 5-methoxyisophthaloyl chloride, and bis (p-chlorophenyl) ether.

9. The method of claim 1, wherein the aromatic diamine has the formula H₂N—B—NH₂Or H₂N—B—Y—B’—NH₂Wherein B and B' represent aromatic carbon nucleus or bivalent non-reactive group to substitute aromatic carbon nucleus, the non-reactive substituent group includes halogen, lower alkyl, phenyl, nitryl, acrylate, alkyl carboxyl, dimethylamino and acetamido; y represents an ether (-O-), a thioether (-S-), a carbonyl (-CO-), a sulpho (-SO-) group connecting two aromatic carbon nuclei which is not reactive with an acid chloride₂-), an N-substituted imino group, an amide, an N-substituted amide or an alkyl ester, and the two amino groups are attached to carbon atoms not adjacent to the aromatic carbon core.

10. The method of claim 1, wherein the organic solvent is at least one of diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, anisole, m-nitroanisole, p-chloroanisole, cyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, p-chloroacetophenone, o-nitroacetophenone, sulfolane, 2, 5-dimethyl sulfoxide, 3-methyl sulfoxide, dichloromethane, chloroform, 1, 2-dichloroethane, chlorobenzene, α -chloronaphthalene, acetonitrile, propionitrile, cyanobenzene, nitrobenzene, nitrotoluene, ethyl acetate, methyl benzoate;

the acid-binding agent is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate sodium bicarbonate, sodium acetate, monopotassium oxalate, dipotassium phthalate, triethylamine, pyridine, 2-methylpyridine, methylmorpholine and hexamethylenetetramine.

Technical Field

The invention belongs to the field of organic material synthesis, and particularly relates to a method for preparing aromatic polyamide by adopting interfacial-solid phase polycondensation.

Background

The special chemical structure of the aromatic polyamide and the copolymer thereof endows the aromatic polyamide and the copolymer thereof with unique performances of high and low temperature resistance, high modulus and high strength, electrical insulation, chemical stability and the like, thereby occupying a great position in high-performance high polymer materials. Currently, the most common method for preparing aromatic polyamides and copolymers thereof in industry is to use aromatic diacid chlorides and aromatic diamines as raw materials and to prepare the aromatic polyamides by low-temperature solution polycondensation.

By adopting a low-temperature solution polycondensation method, side reactions are inevitably generated, and a large amount of inorganic salts, impurities and solvents are generated by a neutralized by-product hydrochloric acid and are difficult to remove, so that the later-stage processing and the product performance are influenced. The Dupont company in the United states proposed polyamide interfacial polycondensation in the sixties of the last century (US3006899) to obtain high-purity polyamide resin, the Kidi company in Japan improved and perfected the process on the basis (US3640970), and on the basis, aromatic polyamide molding powder was prepared by adding reinforcing materials (carbon fibers, aramid fibers and the like) (US4725392), but the preparation research on aromatic polyamide and copolymers thereof in China has been mostly concentrated on low-temperature solution polycondensation, reports on interfacial polycondensation are extremely few, and only the chamotte of Changchun industry university has been reported by a method similar to Kidi (research on m-phenylene isophthalamide preparation by interfacial polycondensation, science and engineering of high polymer materials, 2012 and 12). In 2017, a method for preparing high-purity polyamide particles by adopting m-phenylene isophthalamide solution atomization (a method for preparing particles of m-phenylene isophthalamide solution by atomization, CN201711169454.1) was applied by Hospital, Donghua university, and the like, but the method is complex in process, high in equipment requirement and high in cost.

The adoption of the interfacial polycondensation method can overcome the defect of low-temperature solution polymerization to obtain the polyamide resin with higher purity, but the conventional one-step interfacial polycondensation method cannot obtain high-molecular-weight aromatic polyamide and copolymers thereof in batches due to mass transfer and heat transfer and the like, is sensitive to various process conditions such as stirring and the like, and is not favorable for stable industrial production. So far, all reports related to interfacial polycondensation reaction of aromatic polyamide resin are laboratory tests, and no report is found about batch production method and equipment of interfacial polycondensation.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects and defects mentioned in the background technology, and provide a method for preparing aromatic polyamide by interfacial-solid phase polycondensation, which not only overcomes the problem that impurities and solvents are difficult to remove in low-temperature solution polymerization, but also makes up the problem that the traditional interfacial polycondensation is difficult to prepare polymers with high molecular weight and narrow molecular weight distribution in batch due to the heat and mass transfer problem, thereby obtaining the aromatic polyamide with high molecular weight and high performance.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a process for preparing aromatic polyamides by interfacial-solid phase polycondensation, comprising the steps of:

(1) interfacial polycondensation: adding aromatic diacid chloride, aromatic diamine, an organic solvent and an aqueous solution containing an acid-binding agent into a reactor, mixing and reacting under strong stirring at the rotating speed of 200-1000 rpm, and after the reaction is finished, washing, separating and drying a reaction product to obtain a low-molecular-weight prepolymer; wherein, the aromatic diacid chloride is solid or organic solution; the aromatic diamine is solid, organic solution or aqueous solution;

(2) solid phase polycondensation: and (3) continuously reacting the low molecular weight prepolymer under the protection of inert gas or vacuum to obtain the aromatic polyamide.

In the method, preferably, in the step (1), the reaction temperature is-40 to 100 ℃, and the reaction time is 10s to 30 min.

In the method, preferably, in the step (1), the reaction temperature is-15 to 40 ℃ and the reaction time is 1 to 10 min.

In the above method, preferably, in the step (2), the carrier gas flow rate of the inert gas is 10-500 mL/min, the reaction temperature is 200-350 ℃, and the reaction time is 30 min-72 h; considering the problems of energy consumption and production efficiency, the time is generally not longer than 12 h; the inert gas is any one of nitrogen, argon and carbon dioxide; the prepolymer particles are in a boiling state under the push of an inert gas flow;

or, the reaction is carried out under the vacuum pressure of 100Pa or less, the reaction temperature is 100-350 ℃, and the reaction time is 1-24 h.

In the above method, the aromatic diacid chloride and the aromatic diamine are preferably both at a concentration of 0.01mol/L to 2 mol/L; and the molar ratio of the aromatic diacid chloride to the aromatic diamine is 0.8-1.2.

In the above method, preferably, the concentrations of the aromatic diacid chloride and the aromatic diamine are both 0.2mol/L to 1 mol/L; and the molar ratio of the aromatic diacid chloride to the aromatic diamine is 0.98-1.02.

In the above process, preferably, the aromatic diacid chloride has the formula ClOC-A-COCl or ClOC-A-Y-A' -COCl; wherein A and A' are aromatic carbon cores or divalent non-reactive groups substituted for the aromatic carbon cores, and the non-reactive groups comprise halogens, low-carbon alkyl groups, phenyl groups, acyl groups, acetoxy groups, epoxy groups, nitro groups and sulfonic acid groups; y is an ether (-O-), thioether (-S-), carbonyl (-CO-), sulfo (-SO) -which is unreactive with an acid chloride or amine and connects two aromatic carbon nuclei₂-), an N-substituted imino, amide or N-substituted amide or alkyl ester, and two acid chloride groups are attached to carbon atoms not adjacent to the aromatic carbon core.

In the above method, preferably, the aromatic diacid chloride is selected from one or more of terephthaloyl chloride, isophthaloyl chloride, 1, 4-naphthaloyl chloride, 2, 6-naphthaloyl chloride, 4' -biphenoyl chloride, 5-chloroisophthaloyl chloride, 5-methoxyisophthaloyl chloride and bis (p-chlorobenzene) ether.

In the above method, preferably, the aromatic diamine has the formula of H₂N—B—NH₂Or H₂N—B—Y—B’—NH₂Wherein B and B' represent aromatic carbon nucleus or bivalent non-reactive group to substitute aromatic carbon nucleus, the non-reactive substituent group includes halogen, lower alkyl, phenyl, nitryl, acrylate, alkyl carboxyl, dimethylamino and acetamido; y represents an ether (-O-), a thioether (-S-), a carbonyl (-CO-), a sulpho (-SO-) group connecting two aromatic carbon nuclei which is not reactive with an acid chloride₂-), N-substituted imino, amide, N-substituted amide, or alkyl ester; and the two amino groups are attached to carbon atoms not adjacent to the aromatic carbon core.

In the above method, the organic solvent is preferably at least one of diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, anisole, m-nitroanisole, p-chloroanisole, cyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, p-chloroacetophenone, o-nitroacetophenone, sulfolane, 2, 5-dimethyl sulfoxide, 3-methyl sulfoxide, dichloromethane, chloroform, 1, 2-dichloroethane, chlorobenzene, α -chloronaphthalene, acetonitrile, propionitrile, cyanobenzene, nitrobenzene, nitrotoluene, ethyl acetate, and methyl benzoate;

the acid-binding agent is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate sodium bicarbonate, sodium acetate, monopotassium oxalate, dipotassium phthalate, triethylamine, pyridine, 2-methylpyridine, methylmorpholine and hexamethylenetetramine.

Compared with the prior art, the invention has the advantages that:

(1) the invention adopts an interfacial polycondensation-solid phase polycondensation method to prepare the high molecular weight aromatic polyamide resin, the prepared interfacial pre-polycondensation product and the final product are solid samples, the washing is convenient, the small molecular salt generated in the reaction can be completely removed, and the small molecules can be removed in the processes of prepolymer drying and solid phase polycondensation, so the obtained product is a pure product, thereby overcoming the defects that the subsequent processing and the product performance are influenced because the solvent, the small molecular salt and the like are difficult to remove in the preparation of the aromatic polyamide and the copolymer thereof by a low-temperature solution polycondensation method, and solving the problems that the conventional one-step interfacial polycondensation method cannot prepare the high molecular weight aromatic polyamide in batch due to mass transfer and heat transfer and the like.

(2) The invention can regulate and control the molecular weight, the particle size and the morphology of the resin particles by adjusting the interfacial polycondensation formula and the process parameters, and meanwhile, the method has the advantages of simple process, environmental protection, lower cost and easy realization of batch stable production.

(3) The aromatic polyamide prepared by the invention can be used for preparing molding powder, porous materials, spinning, coating, formulated paint and the like; the application range is wide: high temperature resistant, insulating section bar, high temperature resistant filter media, high temperature adsorption, high temperature resistant carrier, high temperature resistant insulating fiber, film, lacquer, etc.

(4) The method has the advantages of simple process, no need of high temperature for interface pre-polycondensation, energy saving and wide application range; the preparation method adopts a two-step method of interfacial polycondensation and solid-phase polycondensation, and the obtained samples are pure solid particles or powder without impurities, so that the defects of the traditional low-temperature solution polycondensation are overcome (the product of the traditional low-temperature solution polycondensation is a polyamide solution, contains a large amount of solvents and inorganic salts, has low purity, influences the product performance in the later period, and is difficult to store and transport).

Drawings

FIG. 1 is a Fourier-infrared spectrum of m-phenylene isophthalamide resin particles prepared in example 1 of the present invention.

FIG. 2 is a high performance liquid chromatogram of m-phenylene isophthalamide resin particles prepared in example 1 of the present invention.

FIG. 3 is a Fourier-infrared spectrum of a polyamide resin prepared in example 3 of the present invention.

FIG. 4 is a high performance liquid chromatogram of the polyamide resin prepared in example 3 of the present invention.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.