A process for the preparation of 2,5-furandicarboxylic acid

Abstract

The application discloses a method for preparing 2,5-furan dicarboxylic acid, which comprises the following steps: adding CuO foam catalyst, an aqueous solution of tap water disinfectant and pentahydroxymethyl furfural into an alkaline solution to react and obtain 2,5-furan dicarboxylic acid; the CuO foam catalyst is obtained by calcining foam copper at 200 DEG C to 250 DEG C under an oxygen-containing atmosphere. The method for preparing FDCA by adopting the whole CuO foam catalyst solves the problems of difficult catalyst recovery and separation and serious catalyst waste in the above problems, and has the advantages of high oxidation activity agent stability, mild reaction condition and easy operation.

Description

Technical Field

[0001] This application relates to a method for preparing 2,5-furandicarboxylic acid, which belongs to the field of biomass energy chemical industry. Background Technology

[0002] With the increasing depletion of fossil fuels, the development of bio-based chemicals based on biomass has become an inevitable trend. Among them, biomass-based 2,5-furandicarboxylic acid (FDCA) has a similar chemical structure and physicochemical properties to petroleum-based terephthalic acid. In particular, its polyester product with ethylene glycol, polyethylene furanate (PEF), exhibits better performance than polyethylene terephthalate (PET). Therefore, FDCA and its polyester PEF are considered the most ideal bio-based alternatives to terephthalic acid and PET.

[0003] FDCA can be prepared via various routes, among which the 5-hydroxymethylfurfural (HMF) route is the most promising for industrial-scale production. Currently, this oxidation reaction is mainly classified into stoichiometric oxidation, noble metal oxidation, and non-noble metal oxidation methods based on the catalyst used. Compared to the first two oxidation methods, non-noble metals, due to their superior catalytic performance, milder reaction conditions, and lower cost, are more suitable for industrial production and have therefore gained favor among researchers.

[0004] Song Kaihe et al. described the catalytic oxidation of biomass-based compound HMF to FDCA using nano-metal oxides CuO and Co3O4 as catalysts and sodium hypochlorite as oxidant under ambient temperature and pressure, and explored the optimal reaction conditions. (Song Kaihe, Su Kunmei, Li Zhenhuan. Study on the catalytic synthesis of 2,5-furandicarboxylic acid by 5-hydroxymethylfurfural [J]. Modern Chemical Industry, 2019, 39(09):135-140.) Under the optimal reaction conditions, the total yield of the target product FDCA was 98%. The catalysts CuO and Co3O4 showed excellent catalytic performance, and CuO also showed good cycling stability, maintaining high activity after 5 cycles. This indicates that CuO has broad application prospects as a catalyst in this system. However, the separation and recovery of this type of catalyst is difficult, and long-term use of this method for separation will result in catalyst waste and is time-consuming and labor-intensive. Summary of the Invention

[0005] To address the aforementioned problems, this application provides a method for preparing FDCA using an integral CuO foam catalyst, which solves the problems of difficult catalyst recovery and separation and serious catalyst waste.

[0006] According to one aspect of the present application, a method for preparing 2,5-furan dicarboxylic acid is provided, wherein CuO foam catalyst, an aqueous solution of tap water disinfectant, and pentahydroxymethyl furfural are added into an alkaline solution, and reacted to obtain 2,5-furan dicarboxylic acid.

[0007] The CuO foam catalyst is obtained by calcining the foam copper at 200-250°C under an oxygen-containing atmosphere.

[0008] Optionally, the calcination temperature is selected from any value or a range between two values selected from 200°C, 215°C, 230°C, 245°C, and 250°C.

[0009] Optionally, the calcination time is 1-4h.

[0010] Optionally, the calcination time is selected from any value or a range between two values selected from 1h, 2h, 2.5h, 3h, and 4h.

[0011] Optionally, the oxygen-containing atmosphere is air.

[0012] Optionally, the reaction temperature is 35-40°C, and the reaction time is 30-60min.

[0013] Optionally, the reaction temperature is selected from any value or a range between two values selected from 35°C, 36°C, 37°C, 38°C, 39°C, and 40°C.

[0014] Optionally, the reaction time is selected from any value or a range between two values selected from 30min, 35min, 40min, 50min, and 60min.

[0015] Optionally, the mass fraction of the alkaline solution is 0.1-0.3%.

[0016] Optionally, the mass fraction of the alkaline solution is selected from any value or a range between two values selected from 0.1%, 0.15%, 0.2%, 0.25%, and 0.3%.

[0017] Optionally, the base in the alkaline solution is at least one selected from KOH, NaOH, Na2CO3, and K2CO3.

[0018] Optionally, the aqueous solution of tap water disinfectant is at least one selected from hypochlorous acid, sodium hypochlorite, and calcium hypochlorite.

[0019] Optionally, the effective chlorine content in the aqueous solution of tap water disinfectant is >11%.

[0020] Optionally, the mass ratio of pentahydroxymethyl furfural to CuO foam catalyst is 1:(2-20).

[0021] Optionally, the mass ratio of the HMF to the CuO foam catalyst is selected from any ratio or a range between two ratios selected from 1:2, 1:5, 1:10, 1:13, 1:16, 1:20.

[0022] Optionally, the mass ratio of the HMF to the aqueous solution of tap water disinfectant is 1:(1-20), wherein the mass of the aqueous solution of tap water disinfectant is based on the mass of effective chlorine content.

[0023] Optionally, the mass ratio of the HMF to the aqueous solution of tap water disinfectant is selected from any ratio or a range between two ratios selected from 1:1, 1:7, 1:10, 1:15, 1:20.

[0024] Optionally, the alkaline solution is treated in a water bath at 35-40°C.

[0025] The beneficial effects that can be produced by the present application include:

[0026] 1) The method provided by the present application uses a low-cost metal foam which is modified by simple calcination and oxidation to serve as a catalyst for preparing FDCA from HMF, and exhibits high stability of the oxidation active agent.

[0027] 2) The method provided by the present application uses a shaped CuO foam catalyst which is easy to separate and recover from the reaction system, and the reaction device and process conditions are mild and easy to operate. DETAILED DESCRIPTION

[0028] The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

[0029] In the examples of the present application, the raw materials are all purchased through commercial channels unless otherwise specified.

[0030] In the examples of the present application, the analysis methods are as follows:

[0031] The products in the reaction of the present application are analyzed by using a high-performance liquid chromatograph of Model 1260 of Agilent Company, and the external standard method is used for quantification.

[0032] In the examples of the present application, the conversion rate of 5-hydroxymethylfurfural and the yield of 2,5-furan dicarboxylic acid are calculated as follows:

[0033]

[0034]

[0035] In the examples of the present application, the conversion rate of 5-hydroxymethylfurfural and the yield of 2,5-furan dicarboxylic acid are calculated based on the number of moles of carbon:

[0036] Example 1 Catalyst treatment

[0037] The commercially purchased copper foam was calcined and oxidized at 200°C for 2h under air atmosphere to obtain CuO foam catalyst 1#.

[0038] Example 2 Catalyst treatment

[0039] The commercially purchased copper foam was calcined and oxidized at 250°C for 2h under air atmosphere to obtain CuO foam catalyst 2#.

[0040] Preparation of catalyst in Comparative Example 1

[0041] The commercially purchased copper foam was calcined and oxidized at 100°C for 2h under air atmosphere to obtain CuO foam catalyst 3#.

[0042] Preparation of catalyst in Comparative Example 2

[0043] The commercially purchased copper foam was calcined and oxidized at 300°C for 2h under air atmosphere to obtain CuO foam catalyst 4#.

[0044] Preparation of catalyst in Comparative Example 3

[0045] The commercially purchased copper foam was calcined and oxidized at 400°C for 2h under air atmosphere to obtain CuO foam catalyst 5#.

[0046] Comparative Example 4 Catalyst without any treatment

[0047] The commercially purchased copper foam was denoted as Cu foam catalyst 6#.

[0048] Example 3 Reaction performance test of catalysts treated at different calcination temperatures

[0049] 0.1g NaOH, 50g water were added into the reactor, which was placed in a 35°C water bath, and 2g CuO foam catalysts treated in Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3 were added. After the system reached the oxidation temperature, 15g aqueous solution of sodium hypochlorite with an available chlorine content of 11% was added, and 0.126g HMF was added. The reaction was sampled and analyzed after 60min. The results are shown in Table 1:

[0050] Table 1

[0051]

[0052]

[0053] In Table 1, catalyst 5# is commercially purchased copper foam, and the blank is without any catalyst. As shown in Table 1, the conversion rate of HMF and the yield of FDCA are very high using CuO foam catalysts calcined and oxidized at 200°C-250°C.

[0054] Effect of different temperature on reaction

[0055] In the reactor, 0.1 g NaOH, 50 g water were added, and placed in a 35 water bath, 2 g 1# CuO foam catalyst was added, after the system reached the oxidation temperature, 15 g of sodium hypochlorite aqueous solution with effective chlorine content of 11% and 0.126 g HMF were added. The results of sampling analysis at different times are shown in Table 2.

[0056] Table 2

[0057] Temperature / °C HMF conversion / % FDCA yield / % Room temperature 40.32 15.64 38 100 94.40 40 100 89.43

[0058] According to Table 2, under normal temperature conditions, the reactant HMF is not completely converted, and the yield of product FDCA is low. With the increase of temperature to 35℃, HMF is completely converted, and the yield of FDCA is significantly increased. At 35-40℃, the conversion rate of HMF and the yield of FDCA are optimal, reaching more than 90%.

[0059] Effect of different time on reaction

[0060] In the reactor, 0.1 g NaOH, 50 g water were added, and placed in a 35 water bath, 2 g 1# CuO foam catalyst was added, after the system reached the oxidation temperature, 15 g of sodium hypochlorite aqueous solution with effective chlorine content of 11% and 0.126 g HMF were added. The results of sampling analysis at different times are shown in Table 3.

[0061] Table 3

[0062] Time / min HMF conversion / % FDCA yield / % 10 64.12 35.53 20 99.23 84.18 30 100 93.33 40 100 94.16 50 100 89.04 60 100 89.00

[0063] According to Table 3, within 10-30 min, with the increase of time, the conversion rate of HMF and the yield of FDCA are significantly increased; at 40 min, HMF is completely converted, and the yield of FDCA reaches a maximum of more than 94%, and the concentration of reaction product in the reaction system is the highest; within 50-60 min, the conversion rate of HMF is unchanged at 100%, and the yield of reaction product FDCA slightly decreases.

[0064] Test of the number of times of repeated use of CuO foam catalyst

[0065] In the reactor, 0.1 g NaOH, 50 g water were added, and placed in a 35 water bath, 2 g 1# CuO foam catalyst was added, after the system reached the oxidation temperature, 15 g of sodium hypochlorite aqueous solution with effective chlorine content of 11% and 0.126 g HMF were added. The results of sampling analysis at different times are shown in Table 3.

[0066] After the reaction, the catalyst was repeatedly washed with water, and then dried in a 70℃ oven, so that it could be reused.

[0067] Table 4

[0068] Number of runs HMF conversion / % FDCA yield / % 1 100 94.16 2 100 94.23 3 100 94.17 4 100 94.10 5 100 94.35

[0069] The reuse performance of the No. 1 CuO foam catalyst is shown in Table 4. The catalyst can be reused 5 times and HMF can be completely converted. The FDCA yield is 94.10% to 94.35%, which shows that the catalyst has good stability and potential for industrial application.

[0070] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing 2,5-furandicarboxylic acid, characterized in that, CuO foam catalyst, an aqueous solution of tap water disinfectant, and pentahydroxymethylfurfural were added to an alkaline solution and reacted at 35-40℃ for 30-60 minutes to obtain 2,5-furandicarboxylic acid. The CuO foam catalyst is obtained by calcining copper foam at 200-250°C in an oxygen-containing atmosphere.

2. The method according to claim 1, characterized in that, The roasting time is 1 to 4 hours.

3. The method according to claim 1, characterized in that, The oxygen-containing atmosphere is air.

4. The method according to claim 1, characterized in that, The mass fraction of the alkaline solution is 0.1~0.3%.

5. The method according to claim 1, characterized in that, The alkali in the alkaline solution is selected from at least one of KOH, NaOH, K2CO3 or Na2CO3.

6. The method according to claim 1, characterized in that, The aqueous solution of the tap water disinfectant is selected from at least one of hypochlorous acid, sodium hypochlorite, and calcium hypochlorite; The effective chlorine content in the aqueous solution of the tap water disinfectant is >11%.

7. The method according to claim 1, characterized in that, The mass ratio of pentahydroxymethylfurfural to CuO foam catalyst is 1:(2~20).

8. The method according to claim 1, characterized in that, The mass ratio of the pentahydroxymethylfurfural to the aqueous solution of the tap water disinfectant is 1:(1~20), wherein the mass of the aqueous solution of the tap water disinfectant is based on the mass of the available chlorine content.

9. The method according to claim 1, characterized in that, The alkaline solution is treated in a water bath at 35-40°C.

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