阅读说明：本技术 一种制备5,5’-双呋喃二甲酸的方法 (Method for preparing 5,5' -difurandicarboxylic acid ) 是由 尹国川 雷宇 张思成 申冠飞 于 2019-10-17 设计创作，主要内容包括：本发明属于有机合成及催化领域,公开了一种制备5,5’-双呋喃二甲酸的方法,该方法是将同时含有5-溴糠酸、水、无机碱、负载型催化剂及还原剂的反应体系,在60摄氏度～90摄氏度的温度下搅拌反应10分钟～80分钟,即可得到5,5’-双呋喃二甲酸；所述5-溴糠酸具有如下式1所示的化学结构,所述5,5’-双呋喃二甲酸具有如下式2所示的化学结构。本发明利用5-溴糠酸为原料,并通过对参与构建反应体系的各种反应物、以及反应条件等进行改进,与现有技术相比能够有效解决产率不高或反应条件要求苛刻的问题。式1化合物、式2化合物的结构式分别如下：<Image he="126" wi="700" file="DDA0002236747090000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention belongs to the field of organic synthesis and catalysis, and discloses a method for preparing 5,5 '-difurandicarboxylic acid, which comprises the steps of stirring a reaction system simultaneously containing 5-bromofuroic acid, water, inorganic base, a supported catalyst and a reducing agent at the temperature of 60-90 ℃ for 10-80 minutes to react to obtain 5,5' -difurandicarboxylic acid; the 5-bromofuroic acid has a chemical structure shown in the following formula 1, and the 5,5' -difurandicarboxylic acid has a chemical structure shown in the following formula 2. The invention uses 5-bromofuroic acid as raw material, and improves various reactants participating in the construction of a reaction system, reaction conditions and the like, compared with the prior art, the invention can effectively solve the problems of low yield or strict reaction condition requirements. The structural formulas of the compound of formula 1 and the compound of formula 2 are respectively as follows:)

1. A method for preparing 5,5 '-difurandicarboxylic acid is characterized in that a reaction system simultaneously containing 5-bromofuroic acid, water, inorganic base, a supported catalyst and a reducing agent is stirred and reacted for 10 to 80 minutes at a temperature of between 60 and 90 ℃ to obtain 5,5' -difurandicarboxylic acid; wherein the content of the first and second substances,

the 5-bromofuroic acid has a chemical structure shown in the following formula 1, and the 5,5' -difurandicarboxylic acid has a chemical structure shown in the following formula 2:

2. the process according to claim 1, wherein the inorganic base is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, cesium carbonate, preferably sodium hydroxide;

preferably, the reaction system simultaneously containing the 5-bromofuroic acid, the water, the inorganic base, the supported catalyst and the reducing agent is prepared by firstly stirring and dissolving the 5-bromofuroic acid in the water and then adding the inorganic base, wherein the molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5.

3. The method according to claim 1, wherein the supported catalyst is at least one catalyst selected from the group consisting of palladium carbon catalyst, ruthenium carbon catalyst, palladium calcium carbonate, palladium barium sulfate, palladium alumina, palladium silica, platinum carbon catalyst, and bis (dibenzylideneacetone) palladium catalyst, preferably palladium carbon catalyst.

4. The method of claim 1, wherein the reducing agent is at least one of carbon monoxide gas, methanol, sodium formate, hydrogen gas, isopropanol, and ethanol, preferably carbon monoxide gas.

5. The method according to claim 1, wherein the temperature of 60 degrees celsius to 90 degrees celsius is in particular 90 degrees celsius.

6. The method according to claim 1, wherein the stirring reaction is carried out for 10 to 80 minutes, in particular for 80 minutes.

7. The method according to any one of claims 1 to 6, wherein the reaction system is prepared by mixing 5-bromofuroic acid with water, adding an inorganic base, adding a supported catalyst, and finally adding a reducing agent.

8. The method according to any one of claims 1 to 7, wherein the reaction system is obtained by mixing 5-bromofuroic acid with water, adding an inorganic base, adding a palladium-carbon catalyst, vacuumizing the mixed system, replacing with carbon monoxide gas for three times, and using carbon monoxide as a reducing agent; the inorganic base is any one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide and cesium carbonate, and the feeding molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5; then, the reaction system is stirred and reacted for 80 minutes at the temperature of 90 ℃, and the 5,5' -difurandicarboxylic acid can be obtained, wherein the yield is more than 90%.

9. The method according to any one of claims 1 to 7, wherein the reaction system is obtained by mixing 5-bromofuroic acid with water, adding an inorganic base, adding a palladium-carbon catalyst, vacuumizing the mixed system, replacing with carbon monoxide gas for three times, and using carbon monoxide as a reducing agent; wherein the inorganic base is sodium hydroxide or potassium hydroxide, and the feeding molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5; then, the reaction system is stirred and reacted for 30 to 80 minutes at the temperature of 90 ℃, so that the 5,5' -difurandicarboxylic acid can be obtained, and the yield is more than 89.5 percent.

Technical Field

The invention belongs to the field of organic synthesis and catalysis, and particularly relates to a method for preparing 5,5' -difurandicarboxylic acid.

Background

With the exhaustion of fossil energy, the energy crisis is becoming more serious, and the development of new energy is imminent. One important for modern scientistsThe research direction is to explore an environment-friendly process route and develop green renewable resources and energy sources to replace the traditional fossil energy sources. Biomass in a broad sense: the solar energy fixed by photosynthesis can be collectively called biomass, biomass in a narrow sense: fixed by photosynthesis, except fruits and seeds, the biomass is generally called as biomass, and mainly comprises agricultural and forestry wastes such as straws, chaffs, dry branches and fallen leaves and the like. Biomass has two prominent advantages: 1) the biomass is a renewable resource, has wide sources and huge reserves; 2) CO production after biomass consumption₂And H₂O, a raw material for plant photosynthesis, and does not pollute the environment. The above advantages of biomass resources have attracted a wide range of attention by scientists.

5,5' -difurandicarboxylic acid (BFDCA) has a structure and properties similar to those of 4,4 ' -biphenyldicarboxylic acid, and therefore is considered to be a substitute for 4,4 ' -biphenyldicarboxylic acid as a monomer for synthesizing a new generation of biodegradable polyester materials. According to the statistics of research reports of the european bioplastic association, the global bioplastic production rate reaches about 160 ten thousand tons in 2013, and is expected to reach about 610 ten thousand tons by 2021. The 5-bromofuroic acid is mostly extracted and prepared from agricultural and forestry wastes such as corncobs, straws, bagasse, wheat bran, sawdust and the like, has the characteristics of not competing with human beings for grain resources and inexhaustible, and simultaneously, the 5-bromofuroic acid also has the problem of excessive product production capacity caused by insufficient development of downstream products, so that the research on the way of efficiently converting the 5-bromofuroic acid into the self-coupling product can relieve the shortage of grain supply, can widen the utilization way of C5 platform biomass molecules such as the 5-bromofuroic acid and the like, and has important practical significance.

Among them, Naoki et al (see: Journal of polymer science, 2018, 56:1516-1519) directly use dimethyl 2,2' -difuran-5, 5' -dicarboxylate to prepare 5,5' -difurandicarboxylic acid (BFDCA) by a reaction time of 4 hours, and the reaction conditions are severe and the source is synthesized, so that the method is not economical.

Disclosure of Invention

In view of the above defects or improvement requirements of the prior art, the present invention aims to provide a method for preparing 5,5' -difurandicarboxylic acid, wherein 5-bromofuroic acid is used as a raw material, and various reactants participating in the construction of a reaction system, reaction conditions, and the like are improved, so that compared with the prior art, the method can effectively solve the problems of low yield or harsh reaction conditions, and the yield can reach 99.9% at most. The preparation method of the 5,5' -difurandicarboxylic acid ([2,2' -bifuran ] -5,5' -dicarboxylic acid, BFDCA) takes the C5 platform biomass molecule 5-bromofuroic acid with wide source, low price and easy obtaining as a raw material, and can really achieve the purposes of not competing with people for grains and not competing with grains for land compared with the C6 platform biomass raw materials such as HMF and the like, and simultaneously ensure that downstream products of the C5 platform biomass molecule 5-bromofuroic acid are more diversified.

In order to achieve the above object, according to the present invention, there is provided a method for producing 5,5 '-difurandicarboxylic acid, which is characterized in that a reaction system simultaneously containing 5-bromofuroic acid, water, an inorganic base, a supported catalyst and a reducing agent is stirred at a temperature of 60 to 90 ℃ for 10 to 80 minutes to obtain 5,5' -difurandicarboxylic acid; wherein the content of the first and second substances,

the 5-bromofuroic acid has a chemical structure shown in the following formula 1, and the 5,5' -difurandicarboxylic acid has a chemical structure shown in the following formula 2:

as a further preferred aspect of the present invention, the inorganic base is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, and cesium carbonate, preferably sodium hydroxide;

preferably, the reaction system simultaneously containing the 5-bromofuroic acid, the water, the inorganic base, the supported catalyst and the reducing agent is prepared by firstly stirring and dissolving the 5-bromofuroic acid in the water, and then adding the inorganic base, wherein the molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5.

In a further preferred aspect of the present invention, the supported catalyst is at least one of a palladium carbon catalyst, a ruthenium carbon catalyst, palladium calcium carbonate, palladium barium sulfate, palladium alumina, palladium silica, a platinum carbon catalyst, and a bis (dibenzylideneacetone) palladium catalyst, and is preferably a palladium carbon catalyst.

In a further preferred embodiment of the present invention, the reducing agent is at least one of carbon monoxide gas, methanol, sodium formate, hydrogen gas, isopropanol, and ethanol, and carbon monoxide gas is preferred.

As a further preferable aspect of the present invention, the temperature of 60 to 90 degrees celsius is specifically 90 degrees celsius.

In a further preferred embodiment of the present invention, the stirring reaction is carried out for 10 to 80 minutes, specifically for 80 minutes.

As further optimization of the invention, the reaction system is specifically that 5-bromofuroic acid is mixed with water, inorganic base is added, supported catalyst is added, and reducing agent is added.

As a further optimization of the invention, the reaction system is specifically that 5-bromofuroic acid is mixed with water, inorganic base is added, palladium-carbon catalyst is added to vacuumize the mixed system and replace with carbon monoxide gas for three times, and carbon monoxide is used as a reducing agent to obtain the reaction system; the inorganic base is any one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide and cesium carbonate, and the feeding molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5; then, the reaction system was stirred at 90 ℃ for 80 minutes to obtain 5,5' -difurandicarboxylic acid with a yield of 90% or more.

As a further optimization of the invention, the reaction system is specifically that 5-bromofuroic acid is mixed with water, inorganic base is added, palladium-carbon catalyst is added to vacuumize the mixed system and replace with carbon monoxide gas for three times, and carbon monoxide is used as a reducing agent to obtain the reaction system; wherein the inorganic base is sodium hydroxide or potassium hydroxide, and the feeding molar ratio of the 5-bromofuroic acid to the inorganic base is 1: 2.5; then, the reaction system is stirred and reacted for 30 to 80 minutes at the temperature of 90 ℃, so that the 5,5' -difurandicarboxylic acid can be obtained, and the yield is more than 89.5 percent.

Compared with the prior art, the technical scheme of the invention has the advantages that 5,5 '-difurandicarboxylic acid is prepared by taking 5-bromofuroic acid as a substrate, the key overall process flow of the preparation method is controlled and improved, and the preparation of the 5,5' -difurandicarboxylic acid can be realized only by stirring and reacting at the temperature of 60-90 ℃ for 10-80 minutes by controlling various reactants participating in the construction of a reaction system, reaction conditions and the like, and the yield can reach 99.9% to the maximum extent, so that the effect is good.

The invention further enables the reaction steps to realize high yield through the types of the catalysts adopted by the preparation method, the inorganic base used for reaction, the reaction temperature and time and the reducing agent used for reaction, thereby ensuring that the preparation method has high efficiency and the yield can reach 99.9 percent.

The reaction is carried out by reductive coupling of an industrial product 5-bromofuroic acid of furfural in an aqueous medium, and is simple and effective; according to the invention, inorganic base in a reaction system is controlled to be any one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide and cesium carbonate, carbon monoxide is used as a reducing agent, a palladium-carbon catalyst is used as a catalyst, the feeding molar ratio of 5-bromofuroic acid to the inorganic base is controlled to be 1:2.5, then the reaction system is stirred and reacted for 80 minutes at the temperature of 90 ℃ to obtain 5,5' -difuranic acid, and the yield is over 90%; when sodium bicarbonate or potassium bicarbonate is used as the inorganic base, the yield is maintained at 89.5% or more even if the reaction is carried out at 90 ℃ for 30 to 80 minutes. Particularly, when the feeding molar ratio of the 5-bromofuroic acid to the sodium hydroxide (or potassium hydroxide) is 1:2.5, carbon monoxide is used as a reducing agent, a palladium-carbon catalyst is used as a catalyst, the reaction time is 80 minutes at the temperature of 90 ℃, and the yield can reach 99.9%; compared with the prior art which has more complex synthesis method and lower yield, the process method is simpler. The solvent used in the invention is water, which is green and environment-friendly; the used catalyst is preferably a palladium-carbon catalyst, the recycling of the palladium-carbon catalyst and the separation of products are simple, the synthesis scale can be properly enlarged and the palladium-carbon catalyst can be recycled, the recovery rate is reduced by no more than 5 percent after the catalyst is recycled for ten times, and the method is greatly helpful for preparing 5,5' -difurandicarboxylic acid in industrial production.

In summary, the method for preparing 5,5 '-difurandicarboxylic acid in the invention uses 5-bromofuroic acid as a starting material to prepare 5,5' -difurandicarboxylic acid. Compared with other synthesis methods using C6 biomass as a raw material in the prior art, the method uses C5 biomass resource which is rich in source and does not compete with human for grain resources as the raw material, and meanwhile, the method is mild in reaction conditions, simple and convenient to operate, high in repeatability, innovative and high in popularization and application value.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The method for preparing 5,5' -difurandicarboxylic acid in the invention generally comprises the following steps:

mixing 5-bromofuroic acid with water, adding inorganic base, adding a supported catalyst, adding a reducing agent, keeping the temperature at 60-90 ℃, and stirring for reacting for 10-80 minutes to obtain 5,5' -difurandicarboxylic acid;

wherein the structural formulas of the 5-bromofuroic acid (compound shown in formula 1) and the 5,5' -difurandicarboxylic acid (compound shown in formula 2) are respectively as follows:

the inorganic base is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide and cesium carbonate, preferably at least one of sodium hydroxide and potassium hydroxide;

the supported catalyst is at least one of palladium carbon catalyst, ruthenium carbon catalyst, palladium calcium carbonate, palladium barium sulfate, palladium silica, palladium alumina, platinum carbon catalyst and bis (dibenzylideneacetone) palladium catalyst, preferably palladium carbon catalyst;

the reducing agent is at least one of carbon monoxide gas, methanol, sodium formate, hydrogen, isopropanol, formic acid and ethanol, preferably carbon monoxide gas;

the temperature is at least one of 60 ℃ to 90 ℃, preferably 90 ℃.

In the above step, the reaction time is at least one of 10 minutes to 80 minutes, preferably 80 minutes.

Taking inorganic base as sodium hydroxide and reducing agent as carbon monoxide gas as an example, the synthetic route is as follows:

the following are specific examples: