阅读说明：本技术 利用秸秆制备2,5-呋喃二甲酸的方法 (Method for preparing 2, 5-furandicarboxylic acid by using straws ) 是由 陈安伟 柴友正 白马 彭亮 尚翠 邵继海 罗斯 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种利用秸秆制备2,5-呋喃二甲酸的方法,该方法将铬-锰负载USY分子筛整体式催化剂、秸秆与由二甲基亚砜和水组成的混合溶剂混合,加热进行催化反应,得到2,5-呋喃二甲酸,其中铬-锰负载USY分子筛整体式催化剂是以USY分子筛为载体,负载有铬元素和锰元素,铬元素和锰元素以金属氧化物的形态存在。本发明的铬-锰负载USY分子筛整体式催化剂具有催化效率高、产率高、稳定性强、回收效率高、原料成本低、能耗低等优点,用于生成2,5-呋喃二甲酸,其产率可达到67％,适于大规模的批量生产,有很好的市场前景。(The invention discloses a method for preparing 2, 5-furandicarboxylic acid by using straws, which comprises the steps of mixing a chromium-manganese loaded USY molecular sieve monolithic catalyst, straws and a mixed solvent consisting of dimethyl sulfoxide and water, heating and carrying out catalytic reaction to obtain the 2, 5-furandicarboxylic acid, wherein the USY molecular sieve is used as a carrier of the chromium-manganese loaded USY molecular sieve monolithic catalyst, chromium elements and manganese elements are loaded, and the chromium elements and the manganese elements exist in the form of metal oxides. The chromium-manganese loaded USY molecular sieve monolithic catalyst has the advantages of high catalytic efficiency, high yield, strong stability, high recovery efficiency, low raw material cost, low energy consumption and the like, is used for generating 2, 5-furandicarboxylic acid, has the yield reaching 67 percent, is suitable for large-scale batch production, and has good market prospect.)

1. A method for preparing 2, 5-furandicarboxylic acid by using straws is characterized by comprising the following steps: mixing the chromium-manganese loaded USY molecular sieve monolithic catalyst, straws and a mixed solvent, heating to 120-240 ℃ for biomass catalytic reaction to obtain 2, 5-furandicarboxylic acid; the chromium-manganese loaded USY molecular sieve monolithic catalyst takes a USY molecular sieve as a carrier, chromium and manganese elements are loaded on the USY molecular sieve, the chromium and the manganese elements exist in the form of metal oxides, and the mixed solvent consists of dimethyl sulfoxide and water.

2. The method for preparing 2, 5-furandicarboxylic acid from straws as claimed in claim 1, wherein the ratio of the chromium-manganese supported USY molecular sieve monolithic catalyst, straws and mixed solvent is 0.3-1.1 g: 0.5-2 g: 50mL, and the volume ratio of dimethyl sulfoxide to water in the mixed solvent is 1: 1.

3. The method for preparing 2, 5-furandicarboxylic acid from straw according to claim 1, wherein the straw is rice straw.

4. The method for preparing 2, 5-furandicarboxylic acid from straw according to claim 1, wherein the ultrasonic treatment is performed before the heating, the time of the ultrasonic treatment is 30min to 60min, and the time of the biomass catalytic reaction is 4h to 6 h.

5. The method for preparing 2, 5-furandicarboxylic acid from straws as claimed in any one of claims 1 to 4, wherein the loading amount of the chromium element is 3% -9% of the mass of the chromium-manganese supported USY molecular sieve monolithic catalyst, and the loading amount of the manganese element is 3% -9% of the mass of the chromium-manganese supported USY molecular sieve monolithic catalyst.

6. The method for preparing 2, 5-furandicarboxylic acid by using straws as claimed in any one of claims 1 to 4, wherein the preparation method of the chromium-manganese supported USY molecular sieve monolithic catalyst comprises the following steps:

(1) dissolving a manganese nitrate solution, nonahydrate, chromium nitrate and a silica sol solution in water and stirring to obtain a mixed solution;

(2) adding the USY molecular sieve material into the mixed solution, performing ultrasonic treatment, dipping and drying, and calcining at 300-500 ℃ to obtain the chromium-manganese loaded USY molecular sieve monolithic catalyst.

7. The method for preparing 2, 5-furandicarboxylic acid from straws as claimed in claim 6, wherein the ratio of manganese nitrate solution, chromium nitrate nonahydrate, silica sol solution, water and USY molecular sieve material is 0.52 mL-6.18 mL: 1.16 g-3.46 g: 1 mL: 100 mL: 5g, the mass fraction of manganese nitrate solution is 50%, and SiO in the silica sol solution is₂The mass fraction of (B) is 29-31%.

8. The method for preparing 2, 5-furandicarboxylic acid from straw according to claim 6, wherein in the step (2), the time of ultrasonic treatment is 10min to 30min, the temperature of dipping is 80 ℃ to 100 ℃, the time of dipping is 5h to 7h, the temperature of drying is 100 ℃ to 105 ℃, and the time of drying is 1h to 2 h.

9. The method for preparing 2, 5-furandicarboxylic acid from straw according to claim 6, wherein in the step (2), the calcination time is 3 to 5 hours.

Technical Field

The invention belongs to the fields of chemical technology and agricultural waste recycling, relates to the field of biological refining, and particularly relates to a method for preparing 2, 5-furandicarboxylic acid by using straws.

Background

With the rapid development of industry, the increasing exhaustion of energy sources such as fossil fuels leads human beings to seek new sustainable energy sources, and the preparation of biomass into high-value platform compounds is one of the important ways to realize the effective utilization of biomass resources. 2, 5-furandicarboxylic acid is an important furan compound, is listed as one of twelve most representative bio-based platform compounds by the U.S. department of energy, and is also considered as the most suitable substitute of petroleum derivative terephthalic acid. 2, 5-furandicarboxylic acid has a structure similar to that of terephthalic acid, and can replace terephthalic acid as a raw material of widely used polyethylene terephthalate, thereby reducing the dependence on fossil fuels. However, in the current research on the synthesis of 2, 5-furandicarboxylic acid, most of the research is based on 5-hydroxymethylfurfural, fructose, glucose and the like, and the technical development route is very limited. Among them, the synthesis of 2, 5-furandicarboxylic acid from 5-hydroxymethylfurfural oxygen (HMF) is the most important technical route, generally obtained by oxidative synthesis of refined 5-hydroxymethylfurfural oxygen (HMF), or by dehydration of hexose via 5-hydroxymethylfurfural oxygen (HMF). However, the production route based on the refined product has high cost and is difficult to be popularized and applied in a wide range. Therefore, the exploration of direct production of high-value 2, 5-furandicarboxylic acid on the basis of lignocellulosic biomass is a new direction.

Currently, research on the preparation of value-added chemicals from biomass has attracted attention, but lignocellulosic biomass has a complex structure, the conversion rate of a target product is very low, and research on the production of 2, 5-furandicarboxylic acid using biomass is relatively rare. Therefore, how to directly prepare the high-value 2, 5-furandicarboxylic acid chemical through the biomass has very important significance for improving the utilization rate of the biomass.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the method for preparing the 2, 5-furandicarboxylic acid by utilizing the straws, which has the advantages of high catalytic efficiency, high yield, strong stability, high recovery efficiency, low raw material cost and low energy consumption.

In order to solve the technical problems, the invention adopts the following technical scheme.

A method for preparing 2, 5-furandicarboxylic acid by using straws comprises the following steps: mixing the chromium-manganese loaded USY molecular sieve monolithic catalyst, straws and a mixed solvent, heating to 120-240 ℃ for biomass catalytic reaction to obtain 2, 5-furandicarboxylic acid; the chromium-manganese loaded USY molecular sieve monolithic catalyst takes a USY molecular sieve as a carrier, chromium and manganese elements are loaded on the USY molecular sieve, the chromium and the manganese elements exist in the form of metal oxides, and the mixed solvent consists of dimethyl sulfoxide and water.

In the method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, the ratio of the chromium-manganese loaded USY molecular sieve monolithic catalyst to the straws to the mixed solvent is 0.3-1.1 g: 0.5-2 g: 50mL, and the volume ratio of dimethyl sulfoxide to water in the mixed solvent is 1: 1.

In the method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, the straws are rice straws.

In the method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, the ultrasonic treatment is performed before the heating, the time of the ultrasonic treatment is 30-60 min, and the time of the biomass catalytic reaction is 4-6 h.

In the method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, the load capacity of the chromium element is 3-9% of the mass of the chromium-manganese loaded USY molecular sieve monolithic catalyst, and the load capacity of the manganese element is 3-9% of the mass of the chromium-manganese loaded USY molecular sieve monolithic catalyst.

In the above method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, the preparation method of the chromium-manganese supported USY molecular sieve monolithic catalyst comprises the following steps:

(1) dissolving a manganese nitrate solution, nonahydrate, chromium nitrate and a silica sol solution in water and stirring to obtain a mixed solution;

(2) adding the USY molecular sieve material into the mixed solution, performing ultrasonic treatment, dipping and drying, and calcining at 300-500 ℃ to obtain the chromium-manganese loaded USY molecular sieve monolithic catalyst.

Preferably, in the method for preparing 2, 5-furandicarboxylic acid by using straws, the proportion of the manganese nitrate solution, the nonahydrate chromium nitrate, the silica sol solution, the water and the USY molecular sieve material is 0.52-6.18 mL: 1.16 g-3.46 g: 1 mL: 100 mL: 5g, the mass fraction of the manganese nitrate solution is 50%, and SiO in the silica sol solution is₂The mass fraction of (B) is 29-31%. More preferably, the molar ratio of the chromium element in the nonahydrate chromium nitrate to the manganese element in the manganese nitrate solution is 1:1, 1: 2 or 2: 1.

Preferably, in the step (2), the ultrasonic treatment time is 10min to 30min, the dipping temperature is 80 ℃ to 100 ℃, the dipping time is 5h to 7h, the drying temperature is 100 ℃ to 105 ℃, and the drying time is 1h to 2 h.

In the method for preparing 2, 5-furandicarboxylic acid by using straws, preferably, in the step (2), the calcination time is 3-5 h.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides a method for preparing 2, 5-furandicarboxylic acid by using straws, which realizes the aim of directly producing the 2, 5-furandicarboxylic acid from agricultural and forestry waste straws in a catalytic manner and avoids the use of high-cost raw materials. In the invention, the chromium-manganese loaded USY molecular sieve monolithic catalyst takes the USY molecular sieve as a carrier, and chromium and manganese elements are loaded on the USY molecular sieve; the USY molecular sieve is used as a good solid acid carrier and can be effectively combined with Cr and Mn metal elements, and the Cr and Mn metal elements exist on the surface of the catalyst in a metal oxide form after impregnation and calcination, so that the surface of the catalyst has good oxygen mobility, the conversion from straw → hexose → 5-hydroxymethylfurfural → 2, 5-furandicarboxylic acid can be better realized, and the reaction rate of each stage in the process of producing the 2, 5-furandicarboxylic acid by catalyzing the straw is improved. That is, the chromium-manganese bimetallic load in the chromium-manganese load USY molecular sieve monolithic catalyst can realize the direct catalysis of the straws to generate the high-value 2, 5-furandicarboxylic acid. Compared with the existing synthesis method of 2, 5-furandicarboxylic acid, the method for preparing 2, 5-furandicarboxylic acid by using straws has the advantages of low raw material cost, simple operation, low energy consumption, short time consumption, high yield and the like, is suitable for large-scale batch production, and has good market prospect.

(2) In the method, the chromium-manganese loaded USY molecular sieve monolithic catalyst is adopted, and the design of the monolithic catalyst increases the material contact area, and has the advantages of high catalytic efficiency, strong stability, high recovery efficiency and the like.

Drawings

Fig. 1 is a valence state analysis diagram (XPS diagram) of Cr element of the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1 of the present invention.

FIG. 2 is a graph of the valence state analysis (XPS graph) of the Mn element of the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1 of the present invention.

Fig. 3 is an XRD pattern of the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1 of the present invention.

FIG. 4 is a graph showing the effect of different catalyst dosages on the yield of 2, 5-furandicarboxylic acid in example 2 of the present invention.

FIG. 5 is a graph showing the effect of different straw dosages on the yield of 2, 5-furandicarboxylic acid in example 2 of the present invention.

FIG. 6 is a graph showing the effect of different catalytic reaction temperatures on the yield of 2, 5-furandicarboxylic acid in example 2 of the present invention.

FIG. 7 is a graph showing the change in yield of 2, 5-furandicarboxylic acid produced by recycling and catalyzing rice straws with the chromium-manganese supported USY molecular sieve monolithic catalyst in example 3 of the present invention.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention. The materials and equipment used in the following examples are commercially available.

Example 1:

the invention relates to a method for preparing 2, 5-furandicarboxylic acid by using straws, in particular to a method for directly generating the 2, 5-furandicarboxylic acid by using a chromium-manganese loaded USY molecular sieve monolithic catalyst to catalyze the straws, which comprises the following steps:

mixing 0.7g of chromium-manganese loaded USY molecular sieve monolithic catalyst with 1g of rice straw, pouring the mixture into a mixed solvent medium consisting of 50mL of dimethyl sulfoxide and water, carrying out ultrasonic pretreatment for 30min, heating the mixture to 180 ℃ for catalytic reaction for 5h, and carrying out solid-liquid separation by a circulating vacuum pump after the reaction is finished to obtain the 2, 5-furandicarboxylic acid. The concentration of 2, 5-furandicarboxylic acid in the solution obtained by the solid-liquid separation was measured, and the result showed that the yield of 2, 5-furandicarboxylic acid was 67%.

In the embodiment, the adopted chromium-manganese loaded USY molecular sieve monolithic catalyst takes the USY molecular sieve as a carrier, chromium and manganese elements are loaded on the USY molecular sieve, and exist in the form of metal oxide, namely Cr₂O₃、CrO₃、MnO₂、Mn₂O₃、Mn₃O₄Wherein the loading amounts of the chromium element and the manganese element are respectively 6 percent of the total mass of the chromium-manganese loaded USY molecular sieve monolithic catalyst.

In this embodiment, the preparation method of the chromium-manganese supported USY molecular sieve monolithic catalyst comprises the following steps:

(1) 2.31g of nonahydrate, chromium nitrate, 2.06mL of manganese nitrate solution and 1mL of silica sol solution are placed in a beaker, the mass fraction of the manganese nitrate solution is 50%, and SiO in the silica sol solution₂The weight percentage of the solution is 29 to 31 percent, 100mL of ultrapure water is added, and the solution is completely dissolved to form a chromium-manganese mixed solution;

(2) adding 5g of USY molecular sieve into the chromium-manganese mixed solution, carrying out ultrasonic treatment for 20min under a stirring state, then heating and soaking for 6h at 80 ℃, and drying for 1h at 105 ℃ in an oven after soaking is finished to obtain a mixture. And calcining the mixture in a muffle furnace at 400 ℃ for 4h to obtain the chromium-manganese supported USY molecular sieve monolithic catalyst.

Fig. 1 and 2 are XPS plots of Cr and Mn, respectively, in the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1. As can be seen from the figure, Cr exists in +3 and +6 valences, and Mn exists in +2, +3 and +4 valences, which laterally reflects the good oxidation-reduction property of the catalyst surface.

Figure 3 is an XRD pattern of the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1. As can be seen from the figure, the metal elements Cr and Mn exist in the form of oxides on the surface of the catalyst after calcination treatment, which can improve the reaction rate of each stage in the process of producing 2, 5-furandicarboxylic acid by straw catalysis.

Example 2:

the influence of different reaction parameters on the yield of the 2, 5-furandicarboxylic acid is examined, and specifically, the chromium-manganese supported USY molecular sieve monolithic catalyst prepared in example 1 is used for catalyzing straws to generate the 2, 5-furandicarboxylic acid.

(1) Different catalyst addition

Respectively mixing 0.3g, 0.5g, 0.7g, 0.9g and 1.1g of chromium-manganese loaded USY molecular sieve monolithic catalyst with 1g of rice straws, pouring the mixture into a mixed solvent medium consisting of 50mL of dimethyl sulfoxide and water, carrying out ultrasonic pretreatment for 30min, heating, carrying out catalytic reaction at the reaction temperature of 180 ℃ for 5h, carrying out solid-liquid separation by a circulating vacuum pump after the reaction is finished, and detecting the concentration of 2, 5-furandicarboxylic acid in the solution obtained by the solid-liquid separation.

(2) Different amounts of straw

Respectively mixing 0.7g of chromium-manganese loaded USY molecular sieve monolithic catalyst with 0.5g, 1g, 1.5g and 2g of rice straws, pouring the mixture into a mixed solvent medium consisting of 50mL of dimethyl sulfoxide and water, carrying out ultrasonic pretreatment for 30min, heating, carrying out catalytic reaction at the reaction temperature of 180 ℃ for 5h, carrying out solid-liquid separation by a circulating vacuum pump after the reaction is finished to obtain 2, 5-furandicarboxylic acid, and detecting the concentration of the 2, 5-furandicarboxylic acid in the solution obtained by the solid-liquid separation.

(3) Different catalytic reaction temperatures

Mixing 0.7g of chromium-manganese loaded USY molecular sieve monolithic catalyst with 1g of rice straw, pouring the mixture into a mixed solvent medium consisting of 50mL of dimethyl sulfoxide and water, wherein the volume ratio of dimethyl sulfoxide to water in the mixed solvent is 1:1, carrying out ultrasonic pretreatment for 30min, heating, carrying out catalytic reaction for 5h at the reaction temperature of 120 ℃, 150 ℃, 180 ℃, 210 ℃ and 240 ℃ respectively, carrying out solid-liquid separation by a circulating vacuum pump after the reaction is finished to obtain 2, 5-furandicarboxylic acid, and detecting the concentration of the 2, 5-furandicarboxylic acid in the solution obtained by the solid-liquid separation.

Fig. 4 to fig. 6 are graphs showing the effect of different reaction parameters on the yield of 2, 5-furandicarboxylic acid in this example 2, wherein fig. 4 is the effect of different catalyst dosage on the yield, fig. 5 is the effect of different straw dosage on the yield, and fig. 6 is the effect of different catalytic reaction temperatures on the yield. As can be seen from the figure, under the conditions of 0.7g of catalyst dosage, 1g of straw dosage, 180 ℃ of reaction temperature and 5 hours of reaction time, the yield of the 2, 5-furandicarboxylic acid can reach 67 percent.

Example 3:

and (3) inspecting the reusability of the chromium-manganese loaded USY molecular sieve monolithic catalyst in the process of catalyzing and generating 2, 5-furandicarboxylic acid. The monolithic catalyst after the reaction in the example 1 is simply washed by pure water, and is used for the next catalytic reaction after being dried, and the preparation steps are the same as the example 1, namely the reaction parameters are that the adding amount of the catalyst is 0.7g, the adding amount of the straw is 1g, the reaction temperature is 180 ℃, and the reaction time is 5 hours. And after the reaction is finished, entering the next circulation.

Fig. 7 is a graph showing the change in yield of 2, 5-furandicarboxylic acid produced by the chromium-manganese supported USY molecular sieve monolithic catalyst in this example 3 when the catalyst is used to catalyze rice straw in a recycling manner. As can be seen from the figure, the chromium-manganese loaded USY molecular sieve monolithic catalyst has good recycling property, and the catalytic effect is basically kept unchanged in 6 times of recycling, which shows that the catalyst is a novel catalytic material with good stability and high efficiency, and has wide application prospect.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.