A method for inhibiting furfural oxidation in furfural production

Abstract

The invention discloses a method for inhibiting furfural oxidation in furfural production, the method comprising: adding a pentose solution, a catalyst and an oxidation blocking agent into a reactor, starting a reaction device for hydrolysis reaction; during the entire production process, the furfural generated by the reaction is removed from the reaction system through a gas phase extraction valve. The invention can solve the technical problems of the existing method for inhibiting furfural oxidation in furfural production, such as poor furfural oxidation inhibition effect, inability to recycle furfural oxidation inhibitors, and insignificant improvement in furfural yield.

Description

Technical Field

[0001] The invention relates to the technical field of furfural production, and more particularly to a method for inhibiting furfural oxidation during furfural production. Background Art

[0002] At present, most furfural manufacturers use the direct catalytic method of sulfuric acid to produce furfural. The production process is mostly indirect hydrolysis with multiple kettles in series. The production scale is not large, and the yield of furfural can generally only reach about 50%. In the production process of furfural, whether it is a one-step or two-step production process, the loss of furfural generated by the reaction due to oxidation and decomposition accounts for about 30% to 35% of the furfural generated, and furfural oxidation can also cause equipment corrosion, coking and other problems. Therefore, inhibiting the oxidation and decomposition of furfural in the production process is an effective way to increase the yield of furfural, and it is also an important means to solve the corrosion and coking of furfural production equipment.

[0003] In addition to physical measures such as improving the process conditions of the device, adding oxidation inhibitors (including phenolic oxidation inhibitors and amine oxidation inhibitors) is a common method to solve the furfural oxidation problem. However, most of the existing oxidation inhibitors have the following problems: (1) They cannot be recycled, which will greatly increase the economic cost of furfural production. (2) Although some amine oxidation inhibitors have a good effect in inhibiting the oxidative decomposition of furfural, they are highly alkaline and easily soluble in the water of the furfural system, resulting in catalytic decomposition of furfural or furfural-water emulsification problems; (3) The effect of inhibiting the oxidative decomposition of furfural is not ideal, and the effect on improving the furfural yield is not obvious. Therefore, it is necessary to further improve the current method of inhibiting the oxidative decomposition of furfural in furfural production. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to provide a method for inhibiting furfural oxidation in furfural production, so as to solve the technical problems that the existing furfural oxidation inhibition method has poor furfural oxidation inhibition effect, the furfural oxidation inhibitor cannot be recycled, and the furfural yield is not significantly improved.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for inhibiting furfural oxidation in furfural production comprises adding a pentose solution, a catalyst and an oxidation blocking agent into a reactor, starting a reaction device for hydrolysis reaction; during the entire production process, the furfural generated by the reaction is removed from the reaction system through a gas phase extraction valve.

[0007] The method for inhibiting furfural oxidation in the above furfural production, the preparation method of the oxidation blocking agent is:

[0008] Step (1), sequentially subjecting kaolinite to alkaline leaching, acidification and calcination to obtain activated kaolinite;

[0009] Step (2), adding activated kaolinite to a polyethylene polyamine aqueous solution, heating and stirring, then performing solid-liquid separation, and drying and crushing the obtained solid product to obtain an oxidation blocking agent intermediate A;

[0010] Step (3), adding the oxidation blocking agent intermediate A to the α-cellulose solution to cause an oscillation reaction at room temperature, performing solid-liquid separation after the reaction is completed, and washing the obtained solid product with deionized water, drying and crushing at room temperature to obtain the oxidation blocking agent intermediate B;

[0011] Step (4), adding the oxidation blocking agent intermediate B to the glutaraldehyde solution to carry out an oscillating reaction at room temperature, performing solid-liquid separation after the reaction is completed, and washing the obtained solid product with deionized water and then drying and crushing at room temperature to obtain the oxidation blocking agent.

[0012] In the above method for inhibiting furfural oxidation in furfural production, the alkali leaching method in step (1) is as follows: adding kaolinite to a sodium hydroxide solution and soaking it at room temperature, and performing solid-liquid separation after the soaking; washing the obtained solid product with deionized water until it is neutral, and then drying and crushing it to obtain alkali-treated kaolinite;

[0013] The acid treatment method is: adding the alkali-treated kaolinite to a hydrochloric acid solution and soaking it at room temperature, and performing solid-liquid separation after the soaking; washing the obtained solid product with deionized water until it is neutral, and then drying and crushing it to obtain the acid-treated kaolinite;

[0014] The calcination treatment method is: calcining the acid-treated kaolinite, cooling it naturally to room temperature after the calcination, and crushing and sieving it to obtain activated kaolinite.

[0015] The method for inhibiting furfural oxidation in the above furfural production is as follows: during the alkali leaching treatment, the concentration of the sodium hydroxide solution is 0.3-0.6 mol / L, the mass ratio of kaolinite to the sodium hydroxide solution is 1:(8-10), the immersion time is 4-6 hours; the drying temperature is 105-110°C, and the drying time is 8-12 hours;

[0016] During acidification treatment: the concentration of hydrochloric acid solution is 0.2-0.5 mol / L, the mass ratio of alkali-treated kaolinite to hydrochloric acid solution is 1:(6-8), the soaking time is 2-3 hours; the drying temperature is 105-110°C, and the drying time is 8-12 hours;

[0017] During the calcination treatment: the calcination temperature is 800-950°C, the calcination time is 2-3h; the activated kaolinite is sieved through a 200-mesh sieve.

[0018] In the method for inhibiting furfural oxidation in the production of furfural, in step (2), the volume ratio of polyethylene polyamine to water in the polyethylene polyamine aqueous solution is 1: (1-1.5); the mass ratio of activated kaolinite to the polyethylene polyamine aqueous solution is 1: (5-10); the heating and stirring temperature is 80-90° C., and the stirring time is 3-5 hours; the solid product drying temperature is 50-60° C., and the drying time is 8-12 hours.

[0019] In the method for inhibiting furfural oxidation in the production of furfural, in step (3), the α-cellulose solution is prepared by dissolving α-cellulose in an alkaline solution; the mass concentration of α-cellulose in the α-cellulose solution is 3wt% to 5wt%; the mass ratio of the oxidation blocking agent intermediate A to the α-cellulose solution is 1:(10 to 15); and the oscillation reaction conditions are oscillation at 300 to 500 rpm for 5 to 8 hours.

[0020] In the method for inhibiting furfural oxidation in the production of furfural, in step (3), the preparation method of the α-cellulose solution is: adding α-cellulose to an alkaline solution prepared by mixing urea, sodium hydroxide and water, stirring evenly, and then placing it in a 4°C environment and standing for 12 hours to obtain an α-cellulose solution; the mass concentration of urea in the alkaline solution is 10wt% to 15wt%, and the mass concentration of sodium hydroxide is 6wt% to 10wt%.

[0021] In the method for inhibiting furfural oxidation in the production of furfural, in step (4), the volume fraction of glutaraldehyde in the glutaraldehyde solution is 10% to 20%; the mass ratio of the oxidation blocking agent intermediate B to the glutaraldehyde solution is 1:(8 to 12); the oscillation reaction conditions are oscillation at 100 to 300 rpm for 3 to 6 hours; and the oxidation blocking agent is sieved through a 200-mesh sieve.

[0022] The method for inhibiting furfural oxidation in the above-mentioned furfural production is as follows: the content of pentose in the pentose solution is 5wt%-15wt%, and the pentose solution is a xylose solution or a corn cob hydrolyzed pentose solution; the catalyst is one or a mixture of two or more of acetic acid, sulfuric acid or phosphoric acid; the ratio of the amount of the catalyst to the mass of the pentose in the pentose solution is 1:(0.5-5); the amount of the oxidation blocking agent is 0.5-3wt% of the mass of the pentose solution; and the hydrolysis reaction temperature is 140-190°C.

[0023] In the method for inhibiting furfural oxidation in the above furfural production, the pentose solution is a xylose solution, the mass concentration of xylose in the xylose solution is 10wt%; the catalyst is acetic acid, and the ratio of the amount of acetic acid to the mass of xylose in the xylose solution is 1:2; the amount of the oxidation blocker is 1.0wt% of the mass of the xylose solution; the hydrolysis reaction temperature is 170°C; and the preparation method of the oxidation blocker is:

[0024] Step (1), sequentially subjecting kaolinite to alkaline leaching, acidification and calcination to obtain activated kaolinite;

[0025] The alkali leaching treatment method is as follows: adding kaolinite to a sodium hydroxide solution with a concentration of 0.4 mol / L and soaking it at room temperature for 6 hours, and performing solid-liquid separation after the soaking, wherein the mass ratio of kaolinite to the sodium hydroxide solution is 1:10; washing the obtained solid product with deionized water until it is neutral, and then drying it at 105°C for 10 hours and crushing it to obtain alkali-treated kaolinite;

[0026] The acid treatment method is as follows: adding the alkali-treated kaolinite to a 0.2 mol / L hydrochloric acid solution and soaking it at room temperature for 3 hours, and performing solid-liquid separation after soaking, wherein the mass ratio of the alkali-treated kaolinite to the hydrochloric acid solution is 1:8; washing the obtained solid product with deionized water until it is neutral, and then drying it at 105° C. for 10 hours and crushing it to obtain the acid-treated kaolinite;

[0027] The calcination treatment method is as follows: calcining the acid-treated kaolinite at 850°C for 3 hours, cooling it naturally to room temperature after the calcination, and crushing it through a 200-mesh sieve to obtain activated kaolinite;

[0028] Step (2), adding activated kaolinite to a polyethylene polyamine aqueous solution and heating and stirring at 85° C. for 4 hours, wherein the mass ratio of activated kaolinite to the polyethylene polyamine aqueous solution is 1:7, and the volume ratio of polyethylene polyamine to water in the polyethylene polyamine aqueous solution is 1:1.5; then performing solid-liquid separation, and drying the obtained solid product at 55° C. for 10 hours and crushing to obtain an oxidation blocking agent intermediate A;

[0029] Step (3), adding the oxidation blocking agent intermediate A to the α-cellulose solution and oscillating the reaction at room temperature and 500 rpm for 5 hours, wherein the mass ratio of the oxidation blocking agent intermediate A to the α-cellulose solution is 1:10; after the reaction is completed, solid-liquid separation is performed, and the obtained solid product is washed with deionized water and then dried and crushed at room temperature to obtain the oxidation blocking agent intermediate B; the mass concentration of α-cellulose in the α-cellulose solution is 3wt%;

[0030] The preparation method of the α-cellulose solution is as follows: adding α-cellulose to an alkaline solution prepared by mixing urea, sodium hydroxide and water, stirring the mixture evenly, and then placing the mixture in a 4°C environment and standing for 12 hours to obtain the α-cellulose solution; the mass concentration of urea in the alkaline solution is 15wt%, and the mass concentration of sodium hydroxide is 6wt%;

[0031] Step (4), adding the oxidation blocking agent intermediate B to a glutaraldehyde solution having a volume fraction of 15% glutaraldehyde, and oscillating the mixture at room temperature and 200 rpm for 6 hours, wherein the mass ratio of the oxidation blocking agent intermediate B to the glutaraldehyde solution is 1:12; after the reaction, solid-liquid separation is performed, and the obtained solid product is washed with deionized water, dried at room temperature, and crushed through a 200-mesh sieve to obtain an oxidation blocking agent.

[0032] The technical solution of the present invention achieves the following beneficial technical effects:

[0033] 1. The method for inhibiting furfural oxidation in furfural production of the present invention can significantly improve the oxidative decomposition of furfural in furfural production and improve the yield of furfural by adding an oxidation blocker during the furfural production process and removing the generated furfural from the reaction system through a gas phase extraction valve during the production process. The oxidation blocker added in the present invention uses kaolinite as a carrier, and uses polyethylene polyamine, α-cellulose and glutaraldehyde as raw materials. Polyethylene polyamine and α-cellulose are first fixed on kaolinite by adsorption in sequence, and then glutaraldehyde is used to perform a cross-linking reaction to generate a substance with furfural oxidation inhibition activity on kaolinite. The furfural oxidation inhibition active substance is firmly fixed on kaolinite and can react with the furfural oxidation intermediate product-peroxide in the furfural production, thereby achieving the purpose of blocking the furfural oxidation from continuing.

[0034] 2. The furfural oxidation blocker prepared by the present invention can continuously and stably exert the furfural oxidation inhibition effect in the furfural production process, and has a significant inhibitory effect on furfural oxidation, especially under the furfural production process of the present invention, it shows an excellent furfural oxidation blocking effect, greatly improves the yield of furfural, and significantly improves the problem of equipment corrosion and coking caused by furfural oxidation in furfural production. Under the furfural production process conditions of the present invention, the furfural-water azeotrope generated by the reaction is removed from the reaction system through the gas phase extraction valve, and the solid oxidation blocker will remain in the reaction system, thereby realizing the furfural oxidation blocker in the furfural synthesis system for a long time. The oxidation blocker prepared by the present invention does not have the problems of "the existing furfural oxidation inhibitor catalyzing the furfural hydrolysis and furfural-water emulsification caused by dissolving in the furfural reaction system", and can exert the furfural oxidation inhibition effect for a long time, which has obvious advantages over the existing furfural oxidation inhibitor.

[0035] 3. The present invention uses an "alkali leaching-acidification-calcination" treatment method to activate kaolinite when preparing the oxidation blocking agent, which can significantly improve the crystal structure of kaolinite, increase the adsorption sites of kaolinite for polyethylene polyamine and α-cellulose, and provide a rich material basis for the subsequent cross-linking reaction of the two with glutaraldehyde, thereby being able to prepare an oxidation blocking agent with a large loading amount of furfural oxidation inhibitor active substances. If kaolinite is activated by other activation methods such as "acidification-alkali leaching-calcination", "calcination-alkali leaching-acidification" or "acidification-calcination", the oxidation inhibitor finally prepared has a significantly reduced ability to inhibit furfural oxidation. This may be because: the present invention successively uses 0.3-0.6 mol / L sodium hydroxide solution and 0.2-0.5 mol / L hydrochloric acid solution to immerse kaolinite to change the interlayer structure of kaolinite, and then calcination is used to "lock" the change in the crystal phase structure of kaolinite, thereby providing favorable conditions for polyethylene polyamines and α-cellulose to enter the interior of the kaolinite crystal layer during adsorption and achieve "firm and large-scale" adsorption; while other activation methods such as "acidification-alkali leaching-calcination", "calcination-alkali leaching-acidification" or "acidification-calcination" fail to enable kaolinite to finally obtain an ideal crystal phase structure, and thus has a poor adsorption capacity for polyethylene polyamines and α-cellulose (small loading amount or weak adsorption force). DETAILED DESCRIPTION

[0036] Example 1

[0037] In this embodiment, the method for inhibiting furfural oxidation in furfural production is: adding a pentose solution, a catalyst and an oxidation blocking agent into a high-pressure reactor, starting the reaction equipment to perform an intermittent hydrolysis reaction; during the entire production process, the furfural-water azeotrope generated by the reaction is removed from the reaction system through a gas phase extraction valve.

[0038] In this embodiment, the pentose solution is a 10wt% xylose solution; the catalyst is acetic acid, and the ratio of the amount of acetic acid to the mass of xylose in the xylose solution is 1:2; the amount of the oxidation blocker is 1.0wt% of the mass of the xylose solution; the intermittent hydrolysis reaction temperature is 170°C; the preparation method of the oxidation blocker is:

[0039] Step (1), sequentially subjecting kaolinite to alkaline leaching, acidification and calcination to obtain activated kaolinite;

[0040] In this embodiment, the alkali leaching method is: adding kaolinite to a sodium hydroxide solution with a concentration of 0.4 mol / L and soaking it at room temperature for 6 hours, and performing solid-liquid separation after the soaking, and the mass ratio of kaolinite to the sodium hydroxide solution is 1:10; washing the obtained solid product with deionized water until neutral, and then drying it at 105° C. for 10 hours and crushing it to obtain alkali-treated kaolinite;

[0041] In this embodiment, the acid treatment method is: adding the alkali-treated kaolinite to a 0.2 mol / L hydrochloric acid solution and soaking it at room temperature for 3 hours, and performing solid-liquid separation after the soaking, and the mass ratio of the alkali-treated kaolinite to the hydrochloric acid solution is 1:8; washing the obtained solid product with deionized water until neutral, and then drying it at 105°C for 10 hours and crushing it to obtain acid-treated kaolinite;

[0042] In this embodiment, the calcination method is: calcining the acid-treated kaolinite at 850° C. for 3 h, cooling it naturally to room temperature after the calcination, and crushing it through a 200-mesh sieve to obtain activated kaolinite;

[0043] Step (2), adding activated kaolinite to a polyethylene polyamine aqueous solution and heating and stirring at 85° C. for 4 hours, wherein the mass ratio of activated kaolinite to the polyethylene polyamine aqueous solution is 1:7, and the volume ratio of polyethylene polyamine to water in the polyethylene polyamine aqueous solution is 1:1.5; then performing solid-liquid separation, and drying the obtained solid product at 55° C. for 10 hours and crushing to obtain an oxidation blocking agent intermediate A;

[0044] Step (3), adding the oxidation blocking agent intermediate A to the α-cellulose solution and oscillating the reaction at room temperature and 500 rpm for 5 hours, wherein the mass ratio of the oxidation blocking agent intermediate A to the α-cellulose solution is 1:10; after the reaction is completed, solid-liquid separation is performed, and the obtained solid product is washed with deionized water and then dried and crushed at room temperature to obtain the oxidation blocking agent intermediate B; the mass concentration of α-cellulose in the α-cellulose solution is 3wt%;

[0045] In this embodiment, the preparation method of the α-cellulose solution is as follows: α-cellulose is added to an alkaline solution prepared by mixing urea, sodium hydroxide and water, stirred evenly, and then placed in a 4°C environment for 12 hours to obtain an α-cellulose solution; the mass concentration of urea in the alkaline solution is 15wt%, and the mass concentration of sodium hydroxide is 6wt%;

[0046] Step (4), adding the oxidation blocking agent intermediate B to a glutaraldehyde solution having a volume fraction of 15% glutaraldehyde, and oscillating the mixture at room temperature and 200 rpm for 6 hours, wherein the mass ratio of the oxidation blocking agent intermediate B to the glutaraldehyde solution is 1:12; after the reaction, solid-liquid separation is performed, and the obtained solid product is washed with deionized water, dried at room temperature, and crushed through a 200-mesh sieve to obtain an oxidation blocking agent.

[0047] The yield of furfural synthesized in this embodiment is 85%, and the corrosion and coking degree of the reaction equipment are slight; the oxidation blocking agent prepared in this embodiment can be used continuously for a long time under the furfural production process conditions of this embodiment.

[0048] Example 2

[0049] In this embodiment, the method for inhibiting furfural oxidation in furfural production is different from that in Example 1 only in that: in step (1) when preparing the oxidation blocking agent, the kaolinite activation treatment method is different from that in Example 1. Specifically, the kaolinite is subjected to acidification treatment, alkali leaching treatment and calcination treatment in sequence. The specific methods and process parameters of the acidification treatment, alkali leaching treatment and calcination treatment are the same as those in Example 1.

[0050] The yield of furfural synthesized in this example is 77%, and the corrosion and coking degree of the reaction equipment are slightly heavier than those in Example 1; the continuous use time of the oxidation blocking agent prepared in this example is shortened by 30% compared with that in Example 1.

[0051] Example 3

[0052] In this embodiment, the method for inhibiting furfural oxidation in furfural production is different from that in Example 1 only in that: in step (1) when preparing the oxidation blocking agent, the kaolinite activation treatment method is different from that in Example 1. Specifically, the kaolinite is subjected to acidification treatment and calcination treatment in sequence. The specific methods and process parameters of the acidification treatment and calcination treatment are the same as those in Example 1.

[0053] The yield of furfural synthesized in this example is 70%, and the corrosion and coking degree of the reaction equipment are slightly heavier than those in Example 2; the continuous use time of the oxidation blocking agent prepared in this example is shortened by 50% compared with that in Example 1.

[0054] Comparative Example

[0055] In this comparative example, the method for inhibiting furfural oxidation in furfural production is different from that in Example 1 only in that N,N-diethylamine is used as an oxidation blocking agent, and the addition amount thereof is 1000 ppm. Other process methods and parameters are the same as those in Example 1.

[0056] The yield of furfural synthesized in this example is 53%, and the corrosion and coking degree of the reaction equipment are obvious, which is significantly more serious than that in Example 3.

[0057] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for inhibiting furfural oxidation in furfural production, characterized in that, The pentose solution, the catalyst and the oxidation blocking agent are added to the reactor, and the reaction equipment is started to perform a hydrolysis reaction; during the entire production process, the furfural generated by the reaction is removed from the reaction system through the gas phase extraction valve; the preparation method of the oxidation blocking agent is: Step (1), sequentially subjecting kaolinite to alkaline leaching, acidification and calcination to obtain activated kaolinite; Step (2), adding activated kaolinite to a polyethylene polyamine aqueous solution, heating and stirring, then performing solid-liquid separation, and drying and crushing the obtained solid product to obtain an oxidation blocking agent intermediate A; Step (3), adding the oxidation blocking agent intermediate A to the α-cellulose solution to cause an oscillation reaction at room temperature, performing solid-liquid separation after the reaction is completed, and washing the obtained solid product with deionized water, drying and crushing at room temperature to obtain the oxidation blocking agent intermediate B; Step (4), adding the oxidation blocking agent intermediate B to the glutaraldehyde solution to carry out an oscillating reaction at room temperature, performing solid-liquid separation after the reaction is completed, and washing the obtained solid product with deionized water and then drying and crushing at room temperature to obtain the oxidation blocking agent.

2. The method for suppressing furfural oxidation in furfural production according to claim 1, characterized in that: In step (1), the alkali leaching treatment method is: adding kaolinite to a sodium hydroxide solution and soaking it at room temperature, and performing solid-liquid separation after the soaking; washing the obtained solid product with deionized water until it is neutral, and then drying and crushing it to obtain alkali-treated kaolinite; The acid treatment method is: adding the alkali-treated kaolinite to a hydrochloric acid solution and soaking it at room temperature, and performing solid-liquid separation after the soaking; washing the obtained solid product with deionized water until it is neutral, and then drying and crushing it to obtain the acid-treated kaolinite; The calcination treatment method is: calcining the acid-treated kaolinite, cooling it naturally to room temperature after the calcination, and crushing and sieving it to obtain activated kaolinite.

3. The method for suppressing furfural oxidation in furfural production according to claim 2, characterized in that, During alkali leaching treatment: the concentration of sodium hydroxide solution is 0.3-0.6 mol / L, the mass ratio of kaolinite to sodium hydroxide solution is 1:(8-10), the immersion time is 4-6 hours; the drying temperature is 105-110°C, and the drying time is 8-12 hours; During acidification treatment: the concentration of hydrochloric acid solution is 0.2-0.5 mol / L, the mass ratio of alkali-treated kaolinite to hydrochloric acid solution is 1:(6-8), the soaking time is 2-3 hours; the drying temperature is 105-110°C, and the drying time is 8-12 hours; During the calcination treatment: the calcination temperature is 800-950°C, the calcination time is 2-3h; the activated kaolinite is sieved through a 200-mesh sieve.

4. The method for suppressing furfural oxidation in furfural production according to claim 1, characterized in that, In step (2), the volume ratio of polyethylene polyamine to water in the polyethylene polyamine aqueous solution is 1:(1-1.5); the mass ratio of activated kaolinite to the polyethylene polyamine aqueous solution is 1:(5-10); the heating and stirring temperature is 80-90°C, and the stirring time is 3-5h; the solid product drying temperature is 50-60°C, and the drying time is 8-12h.

5. The method for inhibiting furfural oxidation in furfural production according to claim 1, characterized in that, In step (3), the α-cellulose solution is prepared by dissolving α-cellulose in an alkaline solution; the mass concentration of α-cellulose in the α-cellulose solution is 3wt% to 5wt%; the mass ratio of the oxidation blocking agent intermediate A to the α-cellulose solution is 1:(10 to 15); and the oscillation reaction conditions are oscillation at 300 to 500 rpm for 5 to 8 hours.

6. The method for inhibiting furfural oxidation in furfural production according to claim 5, characterized in that: In step (3), the preparation method of the α-cellulose solution is as follows: α-cellulose is added to an alkaline solution prepared by mixing urea, sodium hydroxide and water, stirred evenly, and then placed in a 4°C environment for 12 hours to obtain an α-cellulose solution; the mass concentration of urea in the alkaline solution is 10wt% to 15wt%, and the mass concentration of sodium hydroxide is 6wt% to 10wt%.

7. The method for inhibiting furfural oxidation in furfural production according to claim 1, characterized in that: In step (4), the volume fraction of glutaraldehyde in the glutaraldehyde solution is 10% to 20%; the mass ratio of the oxidation blocking agent intermediate B to the glutaraldehyde solution is 1:(8 to 12); the oscillation reaction conditions are oscillation at 100 to 300 rpm for 3 to 6 hours; and the oxidation blocking agent is sieved through a 200 mesh sieve.

8. The method for inhibiting furfural oxidation in furfural production according to any one of claims 1 to 7, characterized in that: The content of pentose in the pentose solution is 5wt%-15wt%, and the pentose solution is xylose solution or corncob hydrolyzed pentose solution; the catalyst is one or a mixture of two or more of acetic acid, sulfuric acid or phosphoric acid; the ratio of the amount of the catalyst to the mass of the pentose in the pentose solution is 1:(0.5-5); the amount of the oxidation blocking agent is 0.5-3wt% of the mass of the pentose solution; and the hydrolysis reaction temperature is 140-190°C.

9. The method for inhibiting furfural oxidation in furfural production according to claim 8, characterized in that: The pentose solution is a xylose solution, and the mass concentration of xylose in the xylose solution is 10wt%; the catalyst is acetic acid, and the ratio of the amount of acetic acid to the mass of xylose in the xylose solution is 1:2; the amount of the oxidation blocker is 1.0wt% of the mass of the xylose solution; the hydrolysis reaction temperature is 170°C; and the preparation method of the oxidation blocker is: Step (1), sequentially subjecting kaolinite to alkaline leaching, acidification and calcination to obtain activated kaolinite; The alkali leaching treatment method is as follows: adding kaolinite to a sodium hydroxide solution with a concentration of 0.4 mol / L and soaking it at room temperature for 6 hours, and performing solid-liquid separation after the soaking, wherein the mass ratio of kaolinite to the sodium hydroxide solution is 1:10; washing the obtained solid product with deionized water until it is neutral, and then drying it at 105°C for 10 hours and crushing it to obtain alkali-treated kaolinite; The acid treatment method is as follows: adding the alkali-treated kaolinite to a 0.2 mol / L hydrochloric acid solution and soaking it at room temperature for 3 hours, and performing solid-liquid separation after soaking, wherein the mass ratio of the alkali-treated kaolinite to the hydrochloric acid solution is 1:8; washing the obtained solid product with deionized water until it is neutral, and then drying it at 105° C. for 10 hours and crushing it to obtain the acid-treated kaolinite; The calcination treatment method is as follows: calcining the acid-treated kaolinite at 850°C for 3 hours, cooling it naturally to room temperature after the calcination, and crushing it through a 200-mesh sieve to obtain activated kaolinite; Step (2), adding activated kaolinite to a polyethylene polyamine aqueous solution and heating and stirring at 85° C. for 4 hours, wherein the mass ratio of activated kaolinite to the polyethylene polyamine aqueous solution is 1:7, and the volume ratio of polyethylene polyamine to water in the polyethylene polyamine aqueous solution is 1:1.5; then performing solid-liquid separation, and drying the obtained solid product at 55° C. for 10 hours and crushing to obtain an oxidation blocking agent intermediate A; Step (3), adding the oxidation blocking agent intermediate A to the α-cellulose solution and oscillating the reaction at room temperature and 500 rpm for 5 hours, wherein the mass ratio of the oxidation blocking agent intermediate A to the α-cellulose solution is 1:10; after the reaction is completed, solid-liquid separation is performed, and the obtained solid product is washed with deionized water and then dried and crushed at room temperature to obtain the oxidation blocking agent intermediate B; the mass concentration of α-cellulose in the α-cellulose solution is 3wt%; The preparation method of the α-cellulose solution is as follows: adding α-cellulose to an alkaline solution prepared by mixing urea, sodium hydroxide and water, stirring the mixture evenly, and then placing the mixture in a 4°C environment and standing for 12 hours to obtain the α-cellulose solution; the mass concentration of urea in the alkaline solution is 15wt%, and the mass concentration of sodium hydroxide is 6wt%; Step (4), adding the oxidation blocking agent intermediate B to a glutaraldehyde solution having a volume fraction of 15% glutaraldehyde, and oscillating the mixture at room temperature and 200 rpm for 6 hours, wherein the mass ratio of the oxidation blocking agent intermediate B to the glutaraldehyde solution is 1:12; after the reaction, solid-liquid separation is performed, and the obtained solid product is washed with deionized water, dried at room temperature, and crushed through a 200-mesh sieve to obtain an oxidation blocking agent.