A process for the preparation of a bis-(5-carboxyfurfuryl) ether

Abstract

The application discloses a kind of industrial production of double-(5-carboxyl furfuryl) ether method with lower cost, simple purification mode, mild reaction and higher yield, comprising: double-(5-formyl furfuryl) ether and sodium hydroxide are dissolved in water in reactor, and cooling;Tri-chloroisocyanuric acid is added to the solution after cooling, and stirring reaction;Reaction product is added to water and is solid-liquid separation;Liquid obtained by solid-liquid separation is placed in a container, and concentrated hydrochloric acid is added;The obtained solid-liquid mixed solution is solid-liquid separation;The solid obtained by separation is dried to obtain solid;The obtained solid is added to a container containing ethyl acetate, and stirred;The mixed liquid after stirring is solid-liquid separation, and the solid is dried to obtain double-(5-carboxyl furfuryl) ether.The application solves the problems of low efficiency, high production cost, high reaction risk and non-industrial production in the prior art during the production of double-(5-carboxyl furfuryl) ether.

Description

Technical Field

[0001] This invention relates to the field of bio-based chemicals, and more particularly to a method for preparing a bis-(5-carboxyfurfuryl) ether. Background Technology

[0002] Bis-(5-carboxyfurfuryl) ether is an important bio-based chemical that can be used to prepare polyamide materials, which are then widely applied in aerospace materials, microelectronic devices, automotive parts, coatings, and other fields. Furthermore, bis-(5-carboxyfurfuryl) ether can also be used as a prodrug for antiviral drugs.

[0003] Currently, the method suitable for small-scale synthesis of bis-(5-carboxyfurfural) ether is the potassium permanganate oxidation method. However, this method uses a relatively dangerous oxidant, which generates oxygen during the process. If the concentration is too high, the reaction may explode. Furthermore, potassium permanganate is an easily explosive substance, and the procurement process is quite complicated, making it unsuitable for large-scale production. Summary of the Invention

[0004] This invention provides an industrial method for producing bis-(5-carboxyfurfuryl) ether that is low-cost, simple to purify, mild in reaction, and high in yield, in order to solve the problems of low efficiency, high production cost, high reaction risk, and inability to be industrialized in the production of bis-(5-carboxyfurfuryl) ether in the prior art.

[0005] To address the above problems, the present invention provides a method for preparing bis-(5-carboxyfurfuryl) ether, comprising the following steps:

[0006] S1. Dissolve bis-(5-formylfurfuryl) ether and sodium hydroxide in water in a container and cool;

[0007] S2. Add trichloroisocyanuric acid in batches to the solution obtained in S1 and stir the reaction at low temperature;

[0008] S3. Add water to the product obtained from the reaction and perform solid-liquid separation;

[0009] S4. Place the liquid obtained from solid-liquid separation into a container and add concentrated hydrochloric acid;

[0010] S5. Perform solid-liquid separation on the solid-liquid mixture obtained in S4;

[0011] S6. Dry the solid obtained from the separation in S5 to obtain a solid;

[0012] S7. Add the solid obtained in S6 to a container containing ethyl acetate and stir.

[0013] S8. Separate the solid-liquid mixture obtained in S7, and dry the solid to obtain the product.

[0014] This invention proposes an oxidation method for bis-(5-formylfurfuryl) ether to obtain bis-(5-carboxyfurfuryl) ether. The preparation method of this invention has advantages such as high production efficiency, low cost, mild reaction, and convenient operation. Furthermore, the production and purification of the target product is relatively simple, which is of great significance for industrial production.

[0015] In step S1, cooling is performed using an ice bath.

[0016] In step S2, the stirring reaction is carried out under ice bath cooling.

[0017] In step S2, the stirring reaction time is 3.0 to 5.0 hours.

[0018] In step S2, the molar ratio of bis-(5-formylfurfuryl) ether, sodium hydroxide and trichloroisocyanuric acid is 1:1.5-2.5:1.5-2.2, more preferably 1:1.8-2.2:1.76-1.96, and most preferably 1:2:1.86 (i.e. 0.085mol:0.17mol:0.158mol).

[0019] In step S4, the mass percentage of concentrated hydrochloric acid is 36% to 38%.

[0020] In step S7, stirring is performed for 0.5 to 2 hours, with the optimal time being 1 hour.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention uses bis-(5-formylfurfuryl) ether as a raw material and converts the carbonyl group to a carboxyl group through an oxidation reaction. Byproducts are few and easily removed, and the purification method is suitable for large-scale chemical production.

[0023] The oxidant used in the method of the present invention is relatively mild compared to potassium permanganate. The entire reaction process is mild and controllable, and the post-processing is simple and low-cost, making it suitable for large-scale production in factories.

[0024] The entire process of this invention requires a short reaction time and is extremely efficient. The reaction is mild and low-cost, and the purification method is simple and easy to operate, making it suitable for large-scale industrial production. Attached Figure Description

[0025] Figure 1 The reaction route diagram for synthesizing the compounds of this invention;

[0026] Figure 2 The 1H NMR spectrum of bis-(5-formylfurfural) ether;

[0027] Figure 3 This is the mass spectrum of bis-(5-formylfurfuryl) ether. Detailed Implementation

[0028] The reaction route for synthesizing the compounds of this invention is as follows: Figure 1 As shown.

[0029] Example 1: Oxidation of bis-(5-formylfurfural) ether

[0030] Under ice bath cooling, trichloroisocyanuric acid (39.69 g, 0.158 mol) was slowly added to a mixed solution of bis-(5-formylfurfuryl) ether (20 g, 0.085 mol), sodium hydroxide (6.8 g, 0.17 mol), and water (160 ml), and the mixture was stirred for 5.0 h. The mixture was filtered, and the filtrate was acidified with concentrated hydrochloric acid (36.5% by mass). Solid-liquid separation was performed, and the combined solids were slurried with ethyl acetate (stirred for one hour). The filter cake was then filtered and dried to obtain the product, bis-(5-carboxyfurfuryl) ether (purity 97.3%, yield 74%).

[0031] like Figure 2 As shown, the chemical shift of hydrogen in the synthesized compound matches the chemical shift of bis-(5-carboxyfurfuryl) ether.

[0032] like Figure 3 As shown, the chemical shift of hydrogen in the synthesized compound is consistent with the molecular weight of bis-(5-carboxyfurfuryl) ether.

[0033] Example 2 Oxidation of bis-(5-formylfurfural) ether

[0034] Under ice bath cooling, trichloroisocyanuric acid (39.69 g, 0.158 mol) was slowly added to a mixed solution of bis-(5-formylfurfuryl) ether (20 g, 0.085 mol), sodium hydroxide (6.8 g, 0.17 mol), and water (160 ml), and the mixture was stirred for 3.0 h. The mixture was filtered, and the filtrate was acidified with concentrated hydrochloric acid (36.5% by mass). Solid-liquid separation was performed, and the combined solids were slurried with ethyl acetate (stirring for one hour). The filtrate was filtered, and the filter cake was dried to obtain the product, which is bis-(5-carboxyfurfuryl) ether.

Claims

1. A method for preparing bis-(5-carboxyfurfuryl) ether, characterized in that, Includes the following steps: S1. Dissolve bis-(5-formylfurfuryl) ether and sodium hydroxide in water in a reactor and cool the mixture using an ice bath. S2. Add trichloroisocyanuric acid to the cooled solution of S1 and stir the reaction. The stirring reaction is carried out under ice bath cooling and the stirring reaction time is 3.0~5.0h. The molar ratio of the bis-(5-formylfurfuryl) ether, sodium hydroxide, and trichloroisocyanuric acid is 1:1.5~2.5:1.5~2.2; S3. Add water to the product obtained from reaction S2 and perform solid-liquid separation; S4. Place the liquid obtained from the solid-liquid separation in S3 into a container and add concentrated hydrochloric acid; S5. Perform solid-liquid separation on the solid-liquid mixture obtained in S4; S6. Dry the solid obtained from the separation in S5 to obtain a solid; S7. Add the solid obtained in S6 to a container containing ethyl acetate and stir. S8. The mixture after stirring in S7 is subjected to solid-liquid separation, and the solid is dried to obtain bis-(5-carboxyfurfuryl) ether.

2. The method for preparing bis-(5-carboxyfurfuryl) ether according to claim 1, characterized in that, In step S2, the molar ratio of bis-(5-formylfurfuryl) ether, sodium hydroxide and trichloroisocyanuric acid is 1:1.8~2.2:1.76~1.

96.

3. The method for preparing bis-(5-carboxyfurfuryl) ether according to claim 1, characterized in that, In step S4, the mass percentage of concentrated hydrochloric acid is 36%~38%.

4. The method for preparing bis-(5-carboxyfurfuryl) ether according to claim 1, characterized in that, In step S7, stir for 0.5 to 2 hours.

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