阅读说明：本技术 一种以萘、二氧化碳为原料的1,4,5,8-萘四甲酸的合成方法 (Synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid by using naphthalene and carbon dioxide as raw materials ) 是由 朱叶峰 裴晓东 骆艳华 杨修光 吴忠凯 张玲 于 2021-10-20 设计创作，主要内容包括：本发明公开了一种1,4,5,8-萘四甲酸的合成方法,步骤包括：向反应瓶内加入溶剂、萘、催化剂以及Mannich碱配体；然后通入二氧化碳,升温后保温反应；回收溶剂后萃取,浓缩结晶,得到1,4,5,8-萘四甲酸。本发明1,4,5,8-萘四甲酸的合成方法中使用廉价易得的萘、二氧化碳,Mannich碱配体具有强供电性以及大位阻,与钯盐配位,催化效果显著提高,在金属催化作用下经一步反应得到产品1,4,5,8-萘四甲酸,催化反应效率高,反应步骤短、后处理纯化简单、原料易得、生产成本低、环境友好等优势。(The invention discloses a method for synthesizing 1,4,5, 8-naphthalene tetracarboxylic acid, which comprises the following steps: adding a solvent, naphthalene, a catalyst and a Mannich alkali ligand into a reaction bottle; then introducing carbon dioxide, heating and then carrying out heat preservation reaction; recovering solvent, extracting, concentrating and crystallizing to obtain 1,4,5, 8-naphthalene tetracarboxylic acid. The method for synthesizing the 1,4,5, 8-naphthalene tetracarboxylic acid uses cheap and easily-obtained naphthalene and carbon dioxide, the Mannich base ligand has strong power supply and large steric hindrance, is coordinated with palladium salt, has obviously improved catalytic effect, obtains the product 1,4,5, 8-naphthalene tetracarboxylic acid through one-step reaction under the action of metal catalysis, and has the advantages of high catalytic reaction efficiency, short reaction step, simple post-treatment purification, easily-obtained raw materials, low production cost, environmental friendliness and the like.)

1. A method for synthesizing 1,4,5, 8-naphthalene tetracarboxylic acid is characterized by comprising the following steps: adding a solvent, naphthalene, a catalyst and a Mannich alkali ligand into a reaction bottle; then introducing carbon dioxide, heating and then carrying out heat preservation reaction; recovering solvent, extracting, concentrating and crystallizing to obtain 1,4,5, 8-naphthalene tetracarboxylic acid; the reaction formula is as follows:

2. the synthesis method according to claim 1, wherein the catalyst is a composite catalyst of catalyst A and catalyst B.

3. The synthesis method according to claim 2, wherein the catalyst A is a palladium salt.

4. A synthesis method according to claim 3, characterized in that the palladium salt is selected from one or more of palladium chloride, palladium acetate, tetrakis (triphenylphosphine) palladium, palladium trifluoroacetate, palladium acetylacetonate, tris (dibenzylideneacetone) dipalladium.

5. The synthesis method according to claim 2, characterized in that the catalyst B is a silver salt.

6. The synthesis method according to claim 5, wherein the silver salt is selected from one or more of silver nitrate, silver fluoride, silver carbonate, silver acetate, silver trifluoroacetate and silver trifluoromethanesulfonate.

7. The synthesis method according to claim 1, wherein the oxidant is one or more selected from tetrahydrofuran, dioxane and cyclohexane.

8. The synthetic method of claim 1 wherein said Mannich base ligand structure is ligand L1 or ligand L2 as follows:

9. the synthesis method according to claim 1, wherein the molar ratio of the carbon dioxide introduction amount to naphthalene is 10-20:1, the molar ratio of the catalyst A to naphthalene is 0.01-0.05:1, the molar ratio of the catalyst B to naphthalene is 0.01-0.05:1, the molar ratio of the Mannich base ligand to naphthalene is 0.05-0.1:1, and the mass ratio of the solvent to naphthalene is 10-20: 1.

10. The synthesis method according to claim 1, wherein the temperature rise is to 60-90 ℃; and/or the time of the heat preservation reaction is 6-12 h.

Technical Field

The invention belongs to the technical field of polyimide synthesis, and particularly relates to a method for synthesizing 1,4,5, 8-naphthalene tetracarboxylic acid by using naphthalene and carbon dioxide as raw materials.

Background

Polyimides (abbreviated as PI) are a large class of high temperature resistant polymers containing a phthalimide or succinimide ring in the main chain, and are usually synthesized from dianhydrides or diamines. At present, the material is one of the materials with the highest use temperature in the industrialized polymers, the decomposition temperature of the material reaches 550-600 ℃, and the long-term use temperature of the material can reach 200-380 ℃. In addition, the composite material has the characteristics of excellent size, oxidation stability, irradiation resistance, insulating property, chemical corrosion resistance, wear resistance, high strength and the like, is widely applied to the high-tech fields of aviation, aerospace, machinery, electricity, atomic energy, microelectronics, liquid crystal display and the like, and becomes one of indispensable materials in the advanced technological fields of global rockets, aerospace and the like.

1,4,5, 8-naphthalene tetracarboxylic anhydride is one of important dianhydride monomers for preparing polyimide, and industrially, 1,4,5, 8-naphthalene tetracarboxylic anhydride is obtained by dehydrating 1,4,5, 8-naphthalene tetracarboxylic acid. Therefore, it is important to study the synthesis of 1,4,5, 8-naphthalene tetracarboxylic acid for the development of the polyimide industry. Industrially, there are three main routes for the synthesis of 1,4,5, 8-naphthalenetetracarboxylic acid.

Route one: in 1966, Sumitomo chemistry used pyrene as a raw material, and the 1,4,5, 8-naphthalene tetracarboxylic acid was prepared through chlorination, hydrolysis, oxidation and other steps (Sumitomo, Rite 6914, 714 (1966)).

And a second route: in 1972, Mitsubishi chemical reported a synthetic route for 1,4,5, 8-naphthalene tetracarboxylic acid, which was obtained by F-C acylation and ring-closure of acenaphthylene as a raw material (Mitsubishi, Japanese patent laid-open No. 7437, 931 (1972)).

And a third route: patent CN106146283A discloses an industrial preparation method of 1,4,5, 8-naphthalene tetracarboxylic acid, which is prepared by using naphthalene as a raw material through F-C acylation reaction and oxidation-hydrolysis reaction, and the total reaction yield is 71%.

In the synthesis route, the reaction step of the route I is long, the reaction conditions in the hydrolysis process are severe, a large amount of three wastes are generated, and the industrial implementation is not facilitated. The second route and the third route both use F-C acylation reaction, need to be carried out under anhydrous conditions, have harsh reaction conditions, generate a large amount of waste acid such as hydrochloric acid and the like and solid waste of metal salts such as iron, aluminum and the like in the reaction process, have prominent environmental protection problems, and greatly limit the large-scale industrial application of the compound.

Technical personnel continuously research the synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid to obtain a new economic, green and efficient synthesis route of 1,4,5, 8-naphthalene tetracarboxylic acid.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide a method for synthesizing 1,4,5, 8-naphthalene tetracarboxylic acid, which can solve the technical problems of long reaction steps, violent reaction, harsh reaction conditions and generation of a large amount of three wastes in the prior art.

In order to achieve the above object, the present invention provides a method for synthesizing 1,4,5, 8-naphthalene tetracarboxylic acid, comprising the steps of: adding a solvent, naphthalene, a catalyst and a Mannich alkali ligand into a reaction bottle; then introducing carbon dioxide, heating and then carrying out heat preservation reaction; recovering solvent, extracting, concentrating and crystallizing to obtain 1,4,5, 8-naphthalene tetracarboxylic acid; the reaction formula is as follows:

in one embodiment of the present invention, the catalyst is a composite catalyst of catalyst a and catalyst B.

In one embodiment of the present invention, the catalyst a is a palladium salt.

In one embodiment of the invention, the palladium salt is selected from one or more of palladium chloride, palladium acetate, tetrakis (triphenylphosphine) palladium, palladium trifluoroacetate, palladium acetylacetonate, tris (dibenzylideneacetone) dipalladium.

In one embodiment of the present invention, the catalyst B is a silver salt.

In one embodiment of the invention, the silver salt is selected from one or more of silver nitrate, silver fluoride, silver carbonate, silver acetate, silver trifluoroacetate, silver trifluoromethanesulfonate.

In one embodiment of the present invention, the oxidizing agent is selected from one or more of tetrahydrofuran, dioxane and cyclohexane.

In one embodiment of the present invention, the Mannich base ligand structure is ligand L1 or ligand L2 as follows:

in one embodiment of the invention, the molar ratio of the carbon dioxide introduction amount to naphthalene is 10-20:1, the molar ratio of the catalyst A to naphthalene is 0.01-0.05:1, the molar ratio of the catalyst B to naphthalene is 0.01-0.05:1, the molar ratio of the Mannich base ligand to naphthalene is 0.05-0.1:1, and the mass ratio of the solvent to naphthalene is 10-20: 1.

In one embodiment of the present invention, the temperature rise refers to a temperature rise to 60 ℃ to 90 ℃; and/or the time of the heat preservation reaction is 6-12 h.

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

(1) the method for synthesizing the 1,4,5, 8-naphthalene tetracarboxylic acid uses cheap and easily available naphthalene and carbon dioxide, and obtains the product 1,4,5, 8-naphthalene tetracarboxylic acid through one-step reaction under the action of metal catalysis.

(2) The synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid can react at a low temperature of 60-90 ℃, has the advantages of mild conditions, high yield, good product quality and the like, and is favorable for large-scale industrial production.

(3) The synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid adopts palladium-silver bimetallic concerted catalysis, the silver catalyst reacts with alpha-H of naphthalene to generate alpha-naphthalene silver salt, and then the alpha-naphthalene silver salt reacts with palladium to obtain a palladium salt intermediate, and then nucleophilic reaction is carried out to generate a target product, so that the method has concerted catalysis effect, and if the method is only applied to catalytic reaction of single nickel or silver catalyst, the reaction can not be carried out basically.

(4) The ligand adopted by the method is a specific type of ligand specially selected for a reaction system, the Mannich base ligand has strong power supply and large steric hindrance, is coordinated with palladium salt, and has a remarkably improved catalytic effect; if no ligand or a conventional type of ligand (e.g., triphenylphosphine) is added during the reaction, the reaction is essentially not allowed to proceed.

Detailed Description

The following detailed description of specific embodiments of the invention is provided, but it should be understood that the scope of the invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

Example 1: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

The synthesis method comprises the following steps: 388g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 3.4g of palladium acetate (99%, 0.015mol), 3.9g of silver trifluoromethanesulfonate (99%, 0.015mol) and 9.2g of ligand L1 (99%, 0.03mol) are added into a 1000mL reaction bottle, wherein the structure of the ligand L1 is shown as the following formula; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 80 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 6 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 3mol of carbon dioxide in total; after the solvent is recovered by reduced pressure distillation, water and toluene are added into the residue for extraction, and an organic layer is concentrated and crystallized to obtain 81.8g of 1,4,5, 8-naphthalene tetracarboxylic acid, wherein the content of the obtained product is 99.5 percent, and the yield is 89.2 percent;

example 2: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

The synthesis method comprises the following steps: 776g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 1.0g of palladium trifluoroacetate (99%, 0.003mol), 0.8g of silver trifluoroacetate (99%, 0.003mol) and 4.6g of ligand L2 (99%, 0.015mol) are added into a 2000mL reaction bottle, wherein the structure of the ligand L2 is shown as follows; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 90 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 12 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 6mol of carbon dioxide in total; after the solvent is recovered by reduced pressure distillation, water and toluene are added into the residue for extraction, and an organic layer is concentrated and crystallized to obtain 76.4g of 1,4,5, 8-naphthalene tetracarboxylic acid, wherein the content of the obtained product is 99.3 percent, and the yield is 83.2 percent;

example 3: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

The synthesis method comprises the following steps: a 1000mL reaction bottle is filled with 582g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 2.7g of palladium chloride (99%, 0.015mol), 2.6g of silver nitrate (99%, 0.015mol) and 9.2g of ligand L1 (99%, 0.03mol), wherein the structure of the ligand L1 is shown as follows; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 60 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 12 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 6mol of carbon dioxide in total; after the solvent is recovered by reduced pressure distillation, water and toluene are added into the residue for extraction, and an organic layer is concentrated and crystallized to obtain 59.0g of 1,4,5, 8-naphthalene tetracarboxylic acid, wherein the content of the obtained product is 98.7 percent, and the yield is 63.9 percent;

example 4: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

The synthesis method comprises the following steps: a 1000mL reaction bottle is filled with 582g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 2.7g of palladium chloride (99%, 0.015mol), 2.6g of silver nitrate (99%, 0.015mol) and 9.2g of ligand L2 (99%, 0.03mol), wherein the structure of the ligand L2 is shown as follows; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 70 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reacting for 8 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 6mol of carbon dioxide in total; after recovering the solvent by distillation under reduced pressure, water and toluene were added to the residue to extract, and the organic layer was concentrated and crystallized to obtain 69.6g of 1,4,5, 8-naphthalenetetracarboxylic acid, the content of the obtained product was 99.1%, and the yield was 75.6%.

Comparative example 1: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

Comparative example 1 compared to example 1, ligand L1 was not used and the conditions were otherwise the same as in example 1.

The synthesis method comprises the following steps: a1000 mL reaction flask was charged with 388g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 3.4g of palladium acetate (99%, 0.015mol), 3.9g of silver triflate (99%, 0.015 mol); after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 80 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 6 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 3mol of carbon dioxide in total; after recovering the solvent by distillation under reduced pressure, water and toluene were added to the residue to extract, and the organic layer was sampled and analyzed by GC-MS, and no production of 1,4,5, 8-naphthalenetetracarboxylic acid was detected.

Comparative example 2: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

Comparative example 2 was compared with example 1 using a different ligand, comparative example 2 using triphenylphosphine and example 1 using ligand L1, and the other conditions were the same as in example 1.

The synthesis method comprises the following steps: a1000 mL reaction flask was charged with 388g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol), 3.4g of palladium acetate (99%, 0.015mol), 3.9g of silver triflate (99%, 0.015mol), and 7.9g of triphenylphosphine (99%, 0.03 mol); after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 80 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 6 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 3mol of carbon dioxide in total; after recovering the solvent by distillation under reduced pressure, water and toluene were added to the residue to extract, and the organic layer was sampled and analyzed by GC-MS, and no production of 1,4,5, 8-naphthalenetetracarboxylic acid was detected.

Comparative example 3: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

Comparative example 1 compared to example 1, the catalyst used was palladium acetate alone, and the other conditions were the same as in example 1.

The synthesis method comprises the following steps: 388g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol) and 3.4g of palladium acetate (99%, 0.015mol) are added into a 1000mL reaction bottle; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 80 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 6 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 3mol of carbon dioxide in total; and after the solvent is recovered by reduced pressure distillation, adding water and toluene into the residue for extraction, sampling an organic layer, performing GC-MS analysis, and detecting to obtain the 1,4,5, 8-naphthalene tetracarboxylic acid with the content of 0%.

Comparative example 4: synthesis method of 1,4,5, 8-naphthalene tetracarboxylic acid

Comparative example 1 compared to example 1, the catalyst used was silver triflate alone, and the other conditions were the same as in example 1.

The synthesis method comprises the following steps: 388g of dioxane (99%), 38.8g of naphthalene (99%, 0.3mol) and 3.9g of silver trifluoromethanesulfonate (99%, 0.015mol) are added into a 1000mL reaction bottle; after the feeding is finished, continuously introducing carbon dioxide into the reaction bottle under normal pressure, heating to 80 ℃, stirring at the rotating speed of 600rpm, and keeping the temperature for reaction for 6 hours; after the reaction is finished, stopping introducing carbon dioxide, and introducing 3mol of carbon dioxide in total; and after the solvent is recovered by reduced pressure distillation, adding water and toluene into the residue for extraction, sampling an organic layer, performing GC-MS analysis, and detecting to obtain the 1,4,5, 8-naphthalene tetracarboxylic acid with the content of 0%.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.