WO2021212460A1

WO2021212460A1 - Method for autocatalytic preparation of 2,5-furandicarboxaldehyde oxime

Info

Publication number: WO2021212460A1
Application number: PCT/CN2020/086656
Authority: WO
Inventors: 陈金波; 张亚杰; 马中森; 夏长久; 宋亚男; 王乐军
Original assignee: 中国科学院宁波材料技术与工程研究所; 恒天生物基材料工程技术（宁波）有限公司
Priority date: 2020-04-24
Filing date: 2020-04-24
Publication date: 2021-10-28
Also published as: JP2023522920A

Abstract

Disclosed by the present application is a method for autocatalytic preparation of 2,5-furandicarboxaldehyde oxime. The method for the autocatalytic preparation of the 2,5-furandicarboxaldehyde oxime comprises: reacting 2,5-furandicarboxaldehyde with an oxime agent using an acid to produce 2,5-furandicarboxaldehyde oxime as a catalyst, and then continuing the reaction of the remaining 2,5-furandicarboxaldehyde and the oxime agent in the presence of the catalyst to produce the 2,5-furandicarboxaldehyde oxime. The present application uses acid-triggered reaction, and finishes a reaction by means of the self-catalysis of the 2,5-furandicarboxaldehyde oxime, thereby avoiding the use of excessive alkali auxiliaries, and reducing the emission of pollutants. The conversion rate of the 2,5-furandicarboxaldehyde reaches 100%, the selectivity and yield of the 2,5-furandicarboxaldehyde oxime reaches more than 99%, and the reaction conditions are mild. In addition, the method is simple and easy to operate, low in production cost, and suitable for industrial production.

Description

Method for preparing 2,5-furandimedoxime by autocatalysis

Technical field

The application relates to a method for preparing 2,5-furandimedoxime by autocatalysis, which belongs to the technical field of chemical synthesis.

Background technique

As the only sustainable organic carbon resource, biomass can be converted into small-molecule biomass-based platform compounds with high selectivity through biological or chemical methods, and then further chemically catalyzed into high-quality fuel oil and high-value-added chemical products. An important way of material transformation and utilization. Among them, 5-hydroxymethyl furfural (HMF), as an important biomass platform representative product, has a wide range of sources and is an important bridge connecting basic biomass raw materials and high value-added products. The nitrogen-containing heterocyclic compound synthesized by 5-hydroxymethylfurfural through oxidation and nucleophilic substitution reaction, 2,5-furandimedoxime (DFFD) is an important organic synthesis intermediate, and its oxime functional group can be easily converted into poly Functional groups, such as nitrile through dehydration reaction, Beckmann rearrangement to amide through acid catalysis, primary amine through hydrogenation reduction, and nitrogen oxide compound through oxidation reaction, which are used in the preparation of functional high polymer such as polyester, polyurethane, polyamide, etc. Material has extremely high industrial application value. 2,5-Furadoxime also has unique physiological and biochemical properties, has good antibacterial, anti-inflammatory, anti-cancer, and anti-viral effects, and can be used in the synthesis of pharmaceutical intermediates. 2,5-Furandialdehyde oxime is also an important ligand for the formation of metal complexes.

Nucleophilic addition is a more typical and mature method for preparing oximes. Under alkaline conditions, hydroxylamine hydrochloride will remove the hydrochloric acid to free the nucleophilic hydroxylamine, and then hydroxylamine will rapidly undergo nucleophilic substitution reaction with carbonyl compounds to form the final product oxime. Patent WO 2012/004069 reported that in 50% ethanol aqueous solution, using 2 times equivalent of hydroxylamine hydrochloride and potassium acetate additives, refluxing and cooling at 50 ℃ for 1 hour to obtain 2,5-furandimide, its selectivity is 80%. Patent WO 2015/060827 reported that in the same ethanol solvent, 2 times equivalent of hydroxylamine hydrochloride and potassium acetate promoter were used to react at 50°C to obtain 2,5-furandimide. Xu et al. (YMXu et al. ACS Sustainable Chem. Eng. 2018, 6, 3, 2888-2892) used 2.6 times equivalent of hydroxylamine hydrochloride and sodium acetate as a promoter, and condensed and refluxed at 110°C for 2 hours to prepare 2,5 -Furandimide, with a selectivity of 95%. This method has high selectivity for preparing oximes, but requires the use of equivalent chemical equivalents or excessive amounts of hydroxylamine hydrochloride and alkali auxiliary agents. A large amount of inorganic salt by-products will be produced during the reaction process, which will cause serious pollution to the environment and increase processing costs. . In addition, the method has harsh reaction conditions and complicated separation and purification steps, which greatly limits its industrial application.

Summary of the invention

The main purpose of this application is to provide a method for preparing 2,5-furandimedoxime by autocatalysis, so as to overcome the shortcomings of the prior art.

In order to achieve the foregoing invention objectives, the technical solutions adopted in this application include:

The embodiment of the application provides a method for autocatalytically preparing 2,5-furandimide, which includes: triggering the reaction of 2,5-furandimide and an oximating agent with an acid to generate 2,5-furandimide as a catalyst. Furandiformaldehyde is further reacted with the oximating agent under the action of the catalyst, so as to realize the production of 2,5-furandiformaldehyde oxime.

In some embodiments, the method for preparing 2,5-furandimedoxime by autocatalysis includes:

Provide a liquid phase reaction system containing 2,5-furandiformaldehyde and an oximating agent;

Acid is added to the liquid phase reaction system to trigger the reaction of 2,5-furandiformaldehyde and the oximating agent, and generate 2,5-furandiformaldehyde oxime as a catalyst, and then make it under the action of the catalyst The remaining 2,5-furandiformaldehyde and the oximating agent continue to react.

Further, the method includes: after adding acid into the liquid phase reaction system, the pH value of the liquid phase reaction system is 1.0-7.0.

In other embodiments, the method for preparing 2,5-furandimedoxime by autocatalysis includes:

Provide a mixed solution containing 2,5-furandiformaldehyde and acid;

The oximating agent was added to the mixed solution in batches, and the reaction between the 2,5-furandiformaldehyde and the oximating agent was triggered by the acid. Under the action of the catalyst, the remaining 2,5-furandiformaldehyde and the oximating agent continue to react.

In some embodiments, the acid includes inorganic acid, organic acid, etc., but is not limited thereto.

Compared with the prior art, the beneficial effects of this application include at least:

1) The method for autocatalytic preparation of 2,5-furandimedoxime provided in this application uses an acid to trigger the reaction, and 2,5-furandimedoxime is autocatalyzed to complete the reaction process. This method avoids the use of excessive alkali additives, Reduced pollutant emissions, reduced production costs, no three wastes generated in the entire reaction process, environmentally friendly, and the operation process is simple, safe and reliable;

2) The method for autocatalytic preparation of 2,5-furandicarbaldehyde dioxime provided by this application achieves high selectivity under mild temperature conditions (below 90°C) in a short time (60 minutes) And high-yield 2,5-furandiformaldehyde dioxime, the conversion rate of 2,5-furandiformaldehyde can reach 100%, and the selectivity and yield of 2,5-furandicarbaldehyde oxime can reach more than 99%;

3) The autocatalytic method for preparing 2,5-furandimedoxime provided in this application, because 2,5-furandimedoxime is insoluble in water, it is easy to separate 2,5-furandimedoxime from the reaction system. The purity is over 99.5%, which improves the quality of the product;

4) The method for autocatalytic preparation of 2,5-furandiformaldehyde dioxime provided by this application, under the condition that the selectivity of 2,5-furandiformaldehyde oxime is ensured, the hydroxylamine aqueous solution is added in batches, so that the hydroxylamine is completely converted and improved The utilization rate of hydroxylamine raw material is improved, and the reaction safety is increased at the same time;

5) This application does not need to add other catalysts and auxiliaries, does not produce any harmful waste, the reaction conditions are mild, and can be carried out under normal temperature and pressure, and the complete reaction takes only 1 to 60 minutes. The reaction product is filtered to obtain a precipitate, and the precipitate is washed. After drying, the target product 2,5-furandiformaldoxime is obtained. The reaction efficiency is high, the method is simple and easy to operate, the production cost is low, and it is suitable for industrial production.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Fig. 1 is a mass spectrum of 2,5-furandimedoxime prepared in Example 1 of the present application.

Fig. 2 is a high performance liquid chromatogram of 2,5-furandimedoxime prepared in Example 1 of the present application.

Detailed ways

The autocatalytic process is a catalytic process in which the reaction product promotes the reaction speed. It has the characteristics of automatic continuous reaction, high reaction activity, fast reaction speed, and easier product handling. There is no report on the autocatalytic reaction of 2,5-furandimedoxime by adjusting the reaction system to a suitable pH value by acid using hydroxylamine aqueous solution as the oximation agent.

As mentioned above, in view of the shortcomings of the existing technology, the inventor of this case has put forward the technical solution of the application after long-term research and a lot of practice, which provides a method for preparing 2,5-furandiformaldoxime by autocatalysis. Using biomass-derived 2,5-furandiformaldehyde as a raw material, using hydroxylamine aqueous solution as an oximation agent, adding an acid to adjust the pH value of the reaction system, the resulting 2,5-furandiformaldehyde oxime is used as a catalyst to autocatalyze the reaction process. This method avoids the use of excessive alkali additives and can be carried out at room temperature and pressure. The reaction is completed in 1 to 60 minutes. The reaction product is filtered to obtain a precipitate, washed and dried to obtain the target product 2,5-furan The selectivity of formaldehyde oxime and 2,5-furandimide is >99%, and the purity is >99.5%.

The autocatalytic reaction mechanism of the method for autocatalytically preparing 2,5-furandimedoxime in this application may be as follows: In this application, the reaction system is adjusted to 3.0 to 4.0, due to the unique carbon atoms on the 2,5-furandimide furan ring With electron-withdrawing conjugation effect, 2,5-furandicarbaldehyde can easily start the reaction and dehydration to form 2,5-furandicarbaldehyde monooxime; then the oxime hydroxyl group of 2,5-furandicarbaldehyde monooxime undergoes a proton ortho-position transfer reaction, and further Catalyzes 2,5-furandiformaldehyde monooxime continuously to produce 2,5-furandiformaldehyde oxime.

The technical solution, its implementation process and principles will be further explained as follows.

One aspect of the embodiments of the present application provides a method for autocatalytically preparing 2,5-furandimide, which includes: triggering the reaction of 2,5-furandimide and an oximating agent with an acid to generate 2 as a catalyst , 5-furan dicarbaldehyde oxime, and then the remaining 2,5-furan dicarbaldehyde and the oximating agent continue to react under the action of the catalyst, so as to realize the production of 2,5-furan dicarbaldehyde oxime.

In some embodiments, the liquid phase reaction system includes 2,5-furandicarbaldehyde, an oximating agent, and a polar solvent.

In some embodiments, the molar ratio of the oximating agent to 2,5-furandicarbaldehyde is 2-10:1.

In the method for preparing 2,5-furandimide by autocatalysis provided in this application, 2,5-furandimide, polar solvent, acid, and oximating agent are mixed and reacted by autocatalysis to obtain 2,5-furan Diformaldehyde oxime.

Specifically, this application realizes the autocatalytic preparation of 2,5-furandimide by the following technical solution: adding 2,5-furandimide and an oximating agent to a polar solvent, adding an acid to adjust the pH of the solution, Using the autocatalytic effect of 2,5-furandiformaldehyde to catalyze the dehydration of 2,5-furandiformaldehyde to prepare 2,5-furandiformaldehyde; and then using filtration, washing and drying to obtain 2,5-furandiformaldehyde Oxime.

Further, the preparation method at least includes: adding an acid to adjust the initial pH value of the solution, starting the reaction of 2,5-furandiformaldehyde and an oximating agent in a polar solvent, and using the resulting 2,5-furandiformaldehyde oxime as a catalyst The reaction process is completed by autocatalysis; after the reaction is finished, it is naturally cooled to room temperature, filtered, washed and dried to obtain the target product 2,5-furandiformaldoxime.

In some embodiments, the method for preparing 2,5-furandiformaldehyde oxime by autocatalysis includes: adding an acid to the liquid phase reaction system, and the pH value of the liquid phase reaction system is 1.0-7.0.

Further, the method includes: adjusting the initial pH value of the liquid phase reaction system between 3.0 and 4.0 by using an acid. In this application, the pH value is between 3.0 and 4.0, which is more conducive to the attack of the nucleophile hydroxylamine on the carbonyl group, thereby accelerating the reaction rate.

In some embodiments, after adding the acid to the liquid phase reaction system, the mass percentage of the acid in the mixed reactant formed is 0.01 to 2.0 wt%, preferably 0.05 to 2.0 wt%, especially preferably It is 0.05 to 0.5 wt%, particularly preferably 0.1 to 0.5 wt%.

In some more preferred embodiments, the method for preparing 2,5-furandimedoxime by autocatalysis includes:

Provide a mixed solution containing 2,5-furandiformaldehyde and acid;

In some embodiments, the mixed solution includes 2,5-furandicarbaldehyde, an acid, and a polar solvent.

Further, the method includes: preparing the oximating agent into an oximating agent aqueous solution, and then adding the oximating agent aqueous solution to the mixed solution in batches.

Further, the inorganic acid includes any one or a combination of two or more of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and sulfurous acid, but is not limited thereto.

Further, the inorganic acid may be preferably selected from hydrochloric acid, sulfuric acid, etc., but is not limited thereto.

Further, the organic acid includes any one or two of formic acid, acetic acid, lactic acid, propionic acid, butyric acid, caproic acid, succinic acid, citric acid, benzoic acid, oxalic acid, methanesulfonic acid, methanesulfonic acid, etc. A combination of the above, but not limited to this.

Furthermore, the inorganic acid may be preferably selected from acetic acid, oxalic acid, etc., but is not limited thereto.

In some embodiments, the oximating agent is hydroxylamine, and the aqueous oximating agent is an aqueous hydroxylamine solution.

Further, the concentration of the aqueous hydroxylamine solution is 15-85% by weight, preferably 50% by weight.

In some embodiments, the mass ratio of the hydroxylamine aqueous solution to 2,5-furandiformaldehyde is 1 to 5:1.

In some embodiments, the polar solvent includes any one or two or more of water, dimethyl sulfoxide, ethylene glycol, dimethylformamide, acetonitrile, methanol, ethanol, isopropanol, etc. Combination or mixed solvent of water and polar organic solvent, but not limited to this.

Further, the polar solvent is water, but it is not limited thereto.

In some embodiments, the mass ratio of the polar solvent to 2,5-furandiformaldehyde is 5 to 35:1.

Further, the mass ratio of the polar solvent to 2,5-furandiformaldehyde is preferably 10-20:1.

In some embodiments, the reaction conditions of the reaction include: the reaction temperature is 0° C. to 90° C., the time is 1 to 60 min, and the reaction pressure is normal pressure.

Specifically, the upper limit of the reaction temperature is selected from 50°C, 45°C, 30°C, or 25°C, and the lower limit is selected from 5°C, 10°C, 15°C, or 25°C.

Specifically, the upper limit of the reaction time is selected from 60min, 50min, 40min or 30min, and the lower limit is selected from 5min, 10min, 15min or 20min.

Further, the temperature of the reaction is preferably 15°C to 30°C, the time is preferably 5 to 30 minutes, and the reaction pressure is normal pressure.

Further, the method includes: adding 2,5-furandiformaldehyde to water, adjusting the initial pH of the solution by acid, adding hydroxylamine aqueous solution in batches, and filtering, washing and drying after the reaction to obtain the target product 2. 5-furandimedoxime. In this application, since hydroxylamine is easily decomposed by heating, in order to improve the stability and safety of hydroxylamine, the hydroxylamine aqueous solution is added in batches to control the concentration of hydroxylamine in the system.

Further, the method includes: adding the oximating agent aqueous solution (ie, the hydroxylamine aqueous solution) to the mixed solution at least 4 to 8 times.

Further, the mass ratio of the hydroxylamine aqueous solution to the 2,5-furandiformaldehyde added each time is 0.25-0.5:1.

Among them, as one of the more specific embodiments, the method for preparing 2,5-furandiformaldehyde by autocatalysis includes: adding 2,5-furandiformaldehyde, a polar solvent and an aqueous hydroxylamine solution in a certain proportion, and raising the temperature To 0～90℃; add acid, adjust the pH value to a proper range to trigger the reaction; after reacting for 1～60min, cool to room temperature to obtain the reaction product, filter, wash and dry to obtain a white powder solid, which is the target product The general reaction formula of 2,5-furandiformaldehyde oxime is as follows:

Among them, the source of hydroxylamine is hydroxylamine aqueous solution.

Wherein, the polar solvent is water, dimethyl sulfoxide, ethylene glycol, dimethylformamide, acetonitrile, methanol, ethanol, isopropanol, etc. or a mixed solvent of water and an organic solvent.

Wherein, the acid is an inorganic acid or an organic acid.

Wherein, the mass percentage of the acid in the entire reaction system is 0.01 to 2.0 wt%, preferably 0.05 to 2.0 wt%, particularly preferably 0.05 to 0.5 wt%, and particularly preferably 0.1 to 0.5 wt%.

Wherein, the acid makes the pH control range between 1.0 and 7.0, preferably 3.0 to 4.0.

In summary, the method for preparing 2,5-furandimedoxime provided in the present application by autocatalysis uses the generated 2,5-furandimedoxime as a catalyst to complete the reaction process by autocatalysis under mild conditions, which improves the reaction. With efficiency and selectivity of 2,5-furandimedoxime, high-purity 2,5-furandimedoxime is obtained. There is no three wastes in the whole reaction process, which is environmentally friendly, and the operation process is simple, safe and reliable. This application does not need to add other catalysts and auxiliary agents, does not produce any harmful waste, has mild reaction conditions, high reaction efficiency, simple and easy operation, low production cost, and is suitable for industrial production.

In order to make the objectives, technical solutions, and advantages of this application clearer, the invention will be further clarified below in conjunction with specific embodiments and drawings. It should be understood that the specific embodiments described here are only used to explain the present application, but the experimental conditions and setting parameters therein should not be regarded as limitations to the basic technical solution of the present application. And the protection scope of this application is not limited to the following embodiments. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

Unless otherwise specified, the raw materials and reagents in the examples of the present application are all purchased through commercial channels.

The analysis method in the embodiment of this application is as follows:

The product concentration was analyzed by high performance liquid chromatography (HPLC), and the model was Agilent 1260.

The conversion rate and selectivity in the examples of this application are calculated as follows:

In the examples of the present application, the 2,5-furandiformaldehyde conversion rate and the 2,5-furandiformaldehyde oxime selectivity are both calculated based on the number of carbon moles:

Conversion rate of 2,5-furandiformaldehyde = (1-remaining moles of 2,5-furandiformaldehyde/initial moles of 2,5-furandiformaldehyde)×100%

2,5-Furaaldoxime selectivity = (2,5-furandiformaldehyde oxime generated mole number/2,5-furandiformaldehyde conversion mole number)×100%

Example 1

Mix 1mmol 2,5-furandiformaldehyde, 2mL water, and 4.0mmol 50wt.% hydroxylamine aqueous solution, heat to 30℃, then add 0.1wt.% dilute hydrochloric acid, adjust the pH of the reaction system to 3.0, and continue the temperature keeping reaction 5min, after the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C to obtain a white powder solid, which is the target product 2,5-furandimide. The test showed that the selectivity of the product was 99.6%, and the purity was 99.8%.

Example 2

Mix 2mmol 2,5-furandiformaldehyde, 3mL ethanol and 6mmol 70wt.% hydroxylamine aqueous solution, then add 0.5wt.% dilute sulfuric acid, adjust the pH of the reaction system to 4.0, and react at room temperature (25℃) for 1 min. After the end, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C to obtain a white powder solid, which is the target product 2,5-furandimide. After testing, the product The selectivity is 99.5% and the purity is 99.7%.

Example 3

Mix 4mmol 2,5-furandiformaldehyde, 14mL dimethylformamide and 40mmol 15wt.% hydroxylamine aqueous solution, heat to 90℃, then add 0.01wt.% phosphoric acid, adjust the pH of the reaction system to 5.0, continue Incubate the reaction for 30 minutes. After the reaction, cool to room temperature naturally, and distill the reaction product under reduced pressure. Wash the precipitate with deionized water and dry at 100°C to obtain a white powder solid, which is the target product 2,5-furandimide After testing, the selectivity of the product is 99.2%, and the purity is 99.6%.

Example 4

Mix 8mmol of 2,5-furandiformaldehyde, 20mL of water and 18mL of methanol mixed solvent and 16mmol of 85wt.% hydroxylamine aqueous solution, and react in an ice bath (0℃). Then add 0.05wt.% of acetic acid to adjust the pH of the reaction system. To 3.5, continue to react for 60 minutes. After the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C, which is the target product 2,5-furandimide. The test showed that the selectivity of the product was 99.4%, and the purity was 99.8%.

Example 5

Mix 20mmol 2,5-furandiformaldehyde, 44mL dimethylsulfoxide and 100mmol 35wt.% hydroxylamine aqueous solution, heat to 45℃, then add 1.0wt.% oxalic acid, adjust the pH of the reaction system to 6.0, continue After reacting for 10 minutes, after the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry it at 100°C, it is the target product 2,5-furandimedoxime. After testing, the product is The selectivity is 99.2% and the purity is 99.5%.

Example 6

Mix 40mmol 2,5-furandiformaldehyde, 80mL isopropanol, and 240mmol 20wt.% hydroxylamine aqueous solution, heat to 60°C, then add 2.0wt.% citric acid, adjust the pH of the reaction system to 7.0, and continue the reaction for 15 minutes After the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C, which is the target product 2,5-furandimide. After testing, the selectivity of the product It was 99.1%, and the purity was 99.6%.

Example 7

Mix 80mmol of 2,5-furandiformaldehyde and 80mL of water uniformly, heat to 30°C, then add 1.5wt.% sulfurous acid, adjust the pH of the reaction system to 1.0, add 50wt.% hydroxylamine aqueous solution in four times, each Add 160mmol of 50wt.% hydroxylamine aqueous solution at one time and continue the reaction for 20min. After the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C, which is the target product 2,5- Furandimedoxime, after testing, the selectivity of the product is 99.2%, and the purity is 99.3%.

Example 8

Mix 160mmol 2,5-furandiformaldehyde and 100mL water uniformly, heat to 15°C, then add 0.3wt.% propionic acid, adjust the pH of the reaction system to 2.0, add 50wt.% hydroxylamine aqueous solution in eight times, Add 50mmol 50wt.% hydroxylamine aqueous solution each time and continue the reaction for 40min. After the reaction, cool to room temperature naturally, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C, which is the target product 2,5 -Furandimedoxime, after testing, the selectivity of the product is 99.0%, and the purity is 99.2%.

The mass spectrum of the product 2,5-furandimedoxime prepared in the above Examples 1-8 is shown in Figure 1, and the high performance liquid chromatogram is shown in Figure 2.

Comparative example 1

Mix 1mmol of 2,5-furandiformaldehyde, 2mL of water, and 4.0mmol of 50wt.% hydroxylamine aqueous solution. Heat to 30°C. The pH of the reaction system is 8.0. The reaction is kept for 5min. After the reaction is over, cool to room temperature naturally. The precipitate is obtained by filtration, washed with deionized water and dried at 100°C to obtain a white powder solid, which is the target product 2,5-furandimedoxime. After testing, the product has a selectivity of 20% and a purity of 15%. .

Comparative example 2

Mix 2mmol of 2,5-furandiformaldehyde, 3mL of ethanol, and 6mmol of hydroxylamine hydrochloride, then add 20wt.% sodium acetate, adjust the pH of the reaction system to 4.0, and react at room temperature (25°C) for 10 minutes. After the reaction, it is natural Cool to room temperature, filter the reaction product to obtain a precipitate, wash the precipitate with deionized water and dry at 100°C to obtain a white powder solid, which is the target product 2,5-furandimedoxime. After testing, the selectivity of the product is 96%, purity is 85%.

With the above technical solution, the method for autocatalytic preparation of 2,5-furandiformaldehyde dioxime provided by this application can be obtained in a relatively short time (60 minutes) under mild temperature conditions (below 90°C) The high selectivity and high yield of 2,5-furandiformaldehyde dioxime is obtained. The conversion rate of 2,5-furandiformaldehyde can reach 100%, and the selectivity and yield of 2,5-furandicarbaldehyde oxime can reach more than 99%.

The aspects, embodiments, features, and examples of this application should be regarded as illustrative in all aspects and are not intended to limit this application. The scope of this application is only defined by the claims. Without departing from the spirit and scope of the claimed application, those skilled in the art will understand other embodiments, modifications, and uses.

The use of titles and chapters in this application is not meant to limit this application; each chapter can be applied to any aspect, embodiment or feature of this application.

Throughout this application, where a composition is described as having, containing, or including specific components, or where a process is described as having, containing, or including specific process steps, it is expected that the composition taught in the present application is also basically The above consists of or consists of the described components, and the process taught in this application is basically composed of the described process steps or a set of described process steps.

Unless specifically stated otherwise, the use of the terms "include, includes, including" and "have, has, or having" should generally be understood as open-ended and not restrictive.

It should be understood that the order of the steps or the order of performing specific actions is not very important, as long as the teachings of the present application remain operable. In addition, two or more steps or actions can be performed simultaneously.

In addition, the inventor of the present case also conducted experiments with the other raw materials, process operations, and process conditions mentioned in this specification by referring to the methods of the foregoing Examples 1-8, and obtained 2,5-furandimide oxime with the same high selectivity. .

Although the present application has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions and/or additions can be made without departing from the spirit and scope of the present application, and the essence, etc. The effector replaces the elements of the described embodiment. In addition, many modifications can be made to adapt specific situations or materials to the teachings of this application without departing from the scope of this application. Therefore, this article does not intend to limit this application to the specific embodiments disclosed for implementing this application, but intends that this application will include all embodiments falling within the scope of the appended claims. In addition, unless specifically stated otherwise, any use of the terms first, second, etc. does not denote any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

A method for preparing 2,5-furandimide by autocatalysis, which is characterized in that it comprises: triggering the reaction of 2,5-furandimide and an oximating agent with an acid to generate 2,5-furandimide as a catalyst Then, under the action of the catalyst, the remaining 2,5-furandiformaldehyde and the oximating agent continue to react, so as to realize the production of 2,5-furandiformaldehyde oxime.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 1, characterized in that it comprises:

Provide a liquid phase reaction system containing 2,5-furandiformaldehyde and an oximating agent;

Acid is added to the liquid phase reaction system to trigger the reaction between 2,5-furandiformaldehyde and the oximating agent, and generate 2,5-furandiformaldehyde oxime as a catalyst, and then make it under the action of the catalyst The remaining 2,5-furandiformaldehyde and the oximating agent continue to react.
The method for autocatalytically preparing 2,5-furandiformaldehyde according to claim 2, characterized in that: the liquid phase reaction system comprises 2,5-furandiformaldehyde, an oximating agent and a polar solvent; preferably , The molar ratio of the oximating agent to the 2,5-furandimaldehyde is 2-10:1.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 2, characterized in that it comprises: after adding an acid to the liquid phase reaction system, the pH of the liquid phase reaction system is 1.0~ 7.0, preferably 3.0 to 4.0;

And/or, after adding the acid to the liquid phase reaction system, the mass percentage of the acid in the mixed reactant formed is 0.01 to 2.0 wt%, preferably 0.05 to 2.0 wt%, and particularly preferably 0.05 -0.5wt%, particularly preferably 0.1-0.5wt%.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 1, characterized in that it comprises:

Provide a mixed solution containing 2,5-furandiformaldehyde and acid;

The oximating agent was added to the mixed solution in batches, and the reaction between the 2,5-furandiformaldehyde and the oximating agent was triggered by the acid. Under the action of the catalyst, the remaining 2,5-furandiformaldehyde and the oximating agent continue to react.
The method for autocatalytically preparing 2,5-furandimide according to claim 5, characterized in that: the mixed solution comprises 2,5-furandimide, an acid and a polar solvent; and/or, the The method includes: preparing the oximating agent into an oximating agent aqueous solution, and then adding the oximating agent aqueous solution to the mixed solution in batches.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 1, wherein the acid includes an inorganic acid and/or an organic acid; preferably, the inorganic acid includes hydrochloric acid, sulfuric acid, and phosphoric acid. Any one or a combination of two or more of nitric acid and sulfurous acid, especially hydrochloric acid and/or sulfuric acid; preferably, the organic acid includes formic acid, acetic acid, lactic acid, propionic acid, butyric acid, caproic acid, and amber Any one or a combination of two or more of the acid, citric acid, benzoic acid, oxalic acid, methanesulfonic acid, and methanesulfonic acid, particularly preferably acetic acid and/or oxalic acid.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 6, characterized in that: the oximating agent is hydroxylamine, and the oximating agent aqueous solution is a hydroxylamine aqueous solution; preferably, the hydroxylamine aqueous solution The concentration is 15-85% by weight.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 3 or 6, characterized in that: the polar solvent comprises water, dimethyl sulfoxide, ethylene glycol, dimethylformamide Any one or a combination of two or more of acetonitrile, methanol, ethanol, and isopropanol, preferably water; and/or, the mass ratio of the polar solvent to 2,5-furandiformaldehyde is 5 to 35 :1, preferably 10-20:1.
The method for autocatalytically preparing 2,5-furandiformaldehyde oxime according to claim 6, wherein the temperature of the reaction is 0°C to 90°C, preferably 15°C to 30°C, and the reaction time It is 1 to 60 minutes, preferably 5 to 30 minutes, and the reaction pressure is normal pressure;

And/or, the method includes: adding the oximating agent aqueous solution to the mixed solution at least 4 to 8 times.