CN113214196B - Method for preparing bio-based chemicals from lignocellulosic biomass - Google Patents

Abstract

The invention discloses a method for preparing a bio-based chemical by using lignocellulose biomass as a raw material, which comprises the following steps: mixing a polar aprotic solvent with water according to a volume ratio of 10-50: 1 to obtain a composite solvent; adding a holocellulose raw material and an organic acid catalyst into a composite solvent, performing hydrolysis reaction, and separating and purifying to obtain a bio-based chemical; wherein the holocellulose raw material comprises cellulose and hemicellulose; the bio-based chemicals include one or more of furfural, 5-hydroxymethylfurfural, and levulinic acid. The method provided by the invention has the advantages that the holocellulose raw material can be directionally and directly hydrolyzed to generate the furfural compounds and/or levulinic acid, the steps are few, the process is simple, the comprehensive utilization process route of biomass resources is shortened, and the cost is reduced.

Description

Method for preparing bio-based chemicals from lignocellulosic biomass

technical field

The invention relates to the technical field of biomass reuse, in particular to a method for preparing bio-based chemicals using lignocellulosic biomass as raw materials.

Background technique

With the development of industry and the increase of population, energy consumption is increasing, and the greenhouse effect and climate warming caused by the use of petrochemical resources are becoming more and more serious, resulting in the continuous deterioration of the environment and the increasing scarcity of energy, which has become a constraint to human society. The bottleneck of sustainable development, the development of low-cost, safe, environmentally friendly and sustainable new pollution-free energy is imminent. Lignocellulose is an abundant and inexpensive renewable resource on earth, with reserves of about 1.8 trillion tons, equivalent to 64 billion tons of oil. It is a promising alternative to fossil resources, and its high-value transformation and utilization is biomass. An important research direction of energyization.

Lignocellulose is mainly composed of hemicellulose, cellulose and lignin, all of which can be used to prepare high value-added biomass chemicals. Cellulose and hemicellulose can be efficiently converted into furfural compounds (furfural, 5-hydroxymethyl furfural), levulinic acid, fuel ethanol and sugars. Among them, furfural compounds and levulinic acid are both valuable intermediates and are listed as important platform compounds by the US Department of Energy.

However, the structure of lignocellulose is complex and there are many by-products in direct conversion, resulting in low selectivity of target products. Therefore, at present, the method of reusing biomass resources to obtain high-value bio-based chemicals is usually to pre-treat lignocellulose and separate components to obtain cellulose components and hemicellulose components, and then establish Different reaction systems are catalyzed by inorganic acids and hydrolyzed by cellulose components and hemicellulose components to obtain furfural mixtures, levulinic acid and other bio-based chemicals. However, this preparation method has a long process route and high cost.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to propose a method for preparing bio-based chemicals by using lignocellulosic biomass as raw material, aiming to solve the problem that the existing preparation method has a long route.

In order to achieve the above object, the present invention proposes a method for preparing bio-based chemicals using lignocellulosic biomass as a raw material, and the method for preparing bio-based chemicals using lignocellulosic biomass as a raw material includes the following steps:

Mixing the polar aprotic solvent and water in a volume ratio of 10 to 50:1 to obtain a composite solvent;

Add the raw materials of holocellulose and the organic acid catalyst into the composite solvent, hydrolyze the reaction, separate and purify to obtain the bio-based chemicals;

Wherein, the holocellulose raw material comprises cellulose and hemicellulose;

The bio-based chemicals include one or more of furfural, 5-hydroxymethylfurfural, and levulinic acid.

Optionally, in the step of obtaining a composite solvent by mixing the polar aprotic solvent and water in a volume ratio of 10 to 50:1, the polar aprotic solvent includes acetonitrile, methyl isobutyl ketone, 2-methyl at least one of tetrahydrofuran, γ-valerolactone, N,N-dimethylformamide, dimethylsulfoxide and tetrahydrofuran.

Optionally, when the polar aprotic solvent is N,N-dimethylformamide, the bio-based chemical includes levulinic acid; or,

When the polar aprotic solvent is one or more of γ-valerolactone, acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, dimethyl sulfoxide and tetrahydrofuran , the bio-based chemicals include furfural and/or 5-hydroxymethylfurfural; or,

When the polar aprotic solvent is a mixed solvent of N,N-dimethylformamide and other solvents, the bio-based chemicals include at least one of furfural and 5-hydroxymethylfurfural and levulinic acid, Wherein, the other solvent is one or more of γ-valerolactone, acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, dimethyl sulfoxide and tetrahydrofuran.

Optionally, in the steps of adding the monocellulose raw material and the organic acid catalyst into the composite solvent, hydrolysis reaction, separation and purification to obtain the bio-based chemical, the organic acid catalyst includes sulfamic acid, p-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, At least one of cobalt sulfamate tosylate, nickel sulfamate, ammonium sulfamate and sodium sulfamate.

Optionally, in the steps of adding the holocellulose raw material and the organic acid catalyst into the composite solvent, hydrolyzing the reaction, and separating and purifying to obtain the bio-based chemical, the holocellulose raw material includes the holocellulose and the holocellulose model compound. At least one of the holocellulose model compounds is a mixture of cellulose and hemicellulose.

Optionally, in the holocellulose model compound, the mass ratio of the cellulose to the hemicellulose is 1-4:1.

Optionally, in the step of adding the holocellulose raw material and the organic acid catalyst to the composite solvent, hydrolysis reaction, separation and purification to obtain the bio-based chemical, the weight ratio of the organic acid catalyst and the holocellulose raw material is 1. : 2 to 10.

Optionally, in the steps of adding the hemolysate raw material and the organic acid catalyst to the composite solvent, hydrolysis reaction, separation and purification to obtain the bio-based chemical, the conditions of the hydrolysis reaction are, the temperature is 120-200 ° C, and the time is 1 ~10h.

Optionally, in the steps of adding the hemolysate raw material and the organic acid catalyst into the composite solvent, hydrolysis reaction, separation and purification to obtain the bio-based chemical, the hydrolysis reaction is carried out in a nitrogen atmosphere.

In the technical solution provided by the present invention, the holocellulose raw material is placed in a composite solvent formed by mixing a polar aprotic solvent and water according to a specific ratio, and an organic acid catalyst is used for catalysis, so that the holocellulose raw material can be oriented and Directly hydrolyzes to generate furfural compounds and/or levulinic acid, with few steps and simple process, shortens the comprehensive utilization process route of biomass resources, and reduces costs; by converting hemicellulose and cellulose at the same time, it is simple and convenient. It is beneficial to improve the utilization efficiency of biomass resources; by using organic acid catalysts, compared with inorganic acid catalysts, it not only reduces the corrosion of equipment, but also promotes the directional conversion of holocellulose raw materials.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market. In addition, the meaning of "and/or" in the whole text includes three parallel schemes. Taking "A and/or B" as an example, it includes scheme A, scheme B, or scheme satisfying both of A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of technical solutions does not exist. , is not within the scope of protection required by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present invention proposes a method for preparing bio-based chemicals using lignocellulosic biomass as a raw material, and the method for preparing bio-based chemicals using lignocellulosic biomass as a raw material provides a short process route, low cost and low cost. Methods for targeted and selective access to high-value bio-based chemicals.

The method for preparing bio-based chemicals from lignocellulosic biomass includes the following steps:

In step S10, the polar aprotic solvent and water are mixed in a volume ratio of 10-50:1 to obtain a composite solvent.

In this embodiment, the polar aprotic solvent and water are mixed in a specific ratio to prepare a composite solvent, and when the composite solvent is used in the subsequent hydrolysis step, it is helpful for the directional hydrolysis reaction. Common polar aprotic solvents currently on the market can be used in this step to obtain a composite solvent. In one embodiment, the polar aprotic solvent includes acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, N,N-dimethylformamide, dimethylsulfoxide And at least one of tetrahydrofuran, that is, in this embodiment, the polar aprotic solvent can be acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, N,N-di Any one of methylformamide, dimethyl sulfoxide and tetrahydrofuran can also be a mixture of any two of them, or a mixture of any of them (not less than two). When the polar aprotic solvent is a mixture of two or more solvents, the mixture is mixed with water in a volume ratio of 10-50:1 to obtain a composite solvent.

In step S20 , the raw materials of helocellulose and the organic acid catalyst are added to the composite solvent, and the bio-based chemicals are obtained by hydrolysis reaction, separation and purification.

Wherein, the holocellulose raw material includes cellulose and hemicellulose, that is, the biomass material used for hydrolysis in the present invention is a holocellulose raw material including cellulose and hemicellulose. Further, the holocellulose raw material can be holocellulose, holocellulose model compounds, or a mixture of holocellulose and holocellulose model compounds. Wherein, the holocellulose, also known as total cellulose, comes from the agricultural waste after delignification, and refers to the part left after removing the extract and lignin from the agricultural waste (most of which are composed of hemicelluloses). cellulose and cellulose, which may contain a little lignin impurities that are difficult to remove), agricultural wastes can be wheat straw, rice straw, corn stover, sorghum straw, rape straw, cotton stalk, bagasse, rice husk, corn cobs, bamboo, At least one of bamboo chips and wood chips, the method of the present invention creates a new application direction for the reuse of agricultural waste, and improves its reuse efficiency; The mixture, specifically, in the holocellulose model compound, the mass ratio of the cellulose to the hemicellulose is 1-4:1.

Wherein, the product obtained in this step includes one or more of furfural, 5-hydroxymethylfurfural and levulinic acid. By controlling the type of polar aprotic solvent in the composite solvent, the direction of hydrolysis can be controlled, so that the reaction can be directed to generate levulinic acid, or co-produce furfural and 5-hydroxymethylfurfural, or simultaneously generate levulinic acid, furfural and 5-hydroxymethyl furfural. -Hydroxymethyl furfural, during actual production, can be adjusted according to actual needs to obtain the target product, the method of the present invention has high selectivity of the target product and simple product composition, which is helpful for high-value conversion of biomass resources according to actual needs and use. Specifically, in one embodiment, when the polar aprotic solvent is N,N-dimethylformamide, the reaction is directed to generate levulinic acid, that is, the bio-based chemicals include levulinic acid; in another In one embodiment, when the polar aprotic solvent is γ-valerolactone, acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, dimethyl sulfoxide, and tetrahydrofuran One or more, the reaction is directed to produce furfural and/or 5-hydroxymethyl furfural, i.e. furfural compounds; in another embodiment, when the polar aprotic solvent is N,N-dimethylformamide and Mixed solvents of other solvents, and the other solvents are one or more of γ-valerolactone, acetonitrile, methyl isobutyl ketone, 2-methyltetrahydrofuran, γ-valerolactone, dimethyl sulfoxide, and tetrahydrofuran In this case, the reaction produces furfural compounds and levulinic acid, wherein the furfural compounds can be furfural, 5-hydroxymethyl furfural or a mixture of furfural and 5-hydroxymethyl furfural.

In step S20, the acid catalyst is an organic acid or a metal salt of an organic acid. Specifically, in this embodiment, the organic acid catalyst includes sulfamic acid, p-sulfamic acid, cobalt p-toluenesulfonic acid sulfamate, and nickel sulfamate , at least one of ammonium sulfamate and sodium sulfamate. By using organic acids and their metal salts as catalysts, hemicellulose and cellulose can be converted at the same time, and the conversion direction can be controlled.

In order to ensure that hemicellulose and cellulose can be converted at the same time, the weight ratio of the organic acid catalyst and the holocellulose raw material is 1:1-10.

In addition, in order to smoothly hydrolyze cellulose and hemicellulose, the conditions of the hydrolysis reaction are that the temperature is 120-200° C. and the time is 1-10 h.

In addition, the hydrolysis reaction is carried out in a nitrogen atmosphere. Compared with the current practice of using a large amount of organic solvents and inorganic liquid acid catalysts, the reaction in a nitrogen atmosphere can reduce the generation of by-products and avoid environmental pollution.

In the technical solution provided by the present invention, the holocellulose raw material is placed in a composite solvent formed by mixing a polar aprotic solvent and water according to a specific ratio, and an organic acid catalyst is used for catalysis, so that the holocellulose raw material can be oriented and Directly hydrolyzes to generate furfural compounds and/or levulinic acid, with few steps and simple process, shortens the comprehensive utilization process route of biomass resources, and reduces costs; by converting hemicellulose and cellulose at the same time, it is simple and convenient. It is beneficial to improve the utilization efficiency of biomass resources; by using organic acid catalysts, compared with inorganic acid catalysts, it not only reduces the corrosion of equipment, but also promotes the directional conversion of holocellulose raw materials.

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention, and are not intended to limit the present invention.

Example 1

Add 4g p-aminobenzenesulfonic acid, 50mL γ-valerolactone/water mixture (19:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave , replaced the air in the reactor with 1MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 5h, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 28.5%. , the yield of 5-hydroxymethylfurfural was 15.0%, and almost no levulinic acid was detected.

Example 2

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (19:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 42.4%, 5 - The yield of hydroxymethylfurfural was 35.8%, and almost no levulinic acid was detected.

Example 3

Add 4g cobalt sulfamate, 50mL γ-valerolactone/water mixture (19:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, The air in the reaction kettle was replaced with 3MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 4 hours, quickly cooled to room temperature, slowly relieved, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 17.7%. The yield of 5-hydroxymethylfurfural was 3.5%, and almost no levulinic acid was detected.

Example 4

Add 3g sulfamic acid, 50mL γ-valerolactone/water mixture (19:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, and use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 34.1%, 5 -Hydroxymethylfurfural yield was 30.5% with almost no detectable levulinic acid.

Example 5

Add 1 g of sulfamic acid, 50 mL of γ-valerolactone/water mixture (19:1, v:v) and 10 g of holocellulose model compound (containing 6 g of cellulose and 4 g of xylan) into a 500 mL autoclave, and use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 24.1%, 5 -Hydroxymethylfurfural yield was 20.5% with almost no levulinic acid detected.

Example 6

Add 5g sulfamic acid, 50mL γ-valerolactone/water mixture (39:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, and use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 44.2%, 5 - The yield of hydroxymethylfurfural was 34.8%, and almost no levulinic acid was detected.

Example 7

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (39:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 21.2%, 5 -Hydroxymethylfurfural yield was 24.7% with almost no detectable levulinic acid.

Example 8

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 63.8%, 5 - The yield of hydroxymethylfurfural was 35.9%, and almost no levulinic acid was detected.

Example 9

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 170 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 34.5%, 5 -Hydroxymethylfurfural yield was 28.8% with almost no levulinic acid detected.

Example 10

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 190 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 23.7%, 5 -Hydroxymethylfurfural yield was 22.4% with almost no detectable levulinic acid.

Example 11

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 1 h, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 37.1%, 5 - The yield of hydroxymethylfurfural was 33.6%, and almost no levulinic acid was detected.

Example 12

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 6 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 36.8%, 5 -Hydroxymethylfurfural yield was 32.8% with almost no levulinic acid detected.

Example 13

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 5g cellulose and 5g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 65.7%, 5 - The yield of hydroxymethylfurfural was 38.1%, and almost no levulinic acid was detected.

Example 14

Add 4g of sulfamic acid, 50mL of γ-valerolactone/water mixed solution (25:1, v:v) and 10g of corncob cellulose into a 500mL autoclave, replace the air in the reactor with 3MPa nitrogen three times, and then recharge Introduce 3MPa nitrogen, heat and stir at 180°C for 4h, quickly cool to room temperature, slowly release pressure, filter, collect the filtrate, and distill under reduced pressure to obtain the product. The yield of furfural is 34.9%, and the yield of 5-hydroxymethylfurfural is 29.8%. Almost no levulinic acid was detected.

Example 15

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g wheat straw cellulose into a 500mL autoclave, replace the air in the reactor with 3MPa nitrogen three times, and refill Introduce 3MPa nitrogen, heat and stir at 180°C for 4h, quickly cool to room temperature, slowly release pressure, filter, collect the filtrate, and distill under reduced pressure to obtain the product. The yield of furfural is 27.3%, and the yield of 5-hydroxymethylfurfural is 29.7%. Almost no levulinic acid was detected.

Example 16

4g sulfamic acid, 50mL composite solvent (polar aprotic solvent/water mixture, 25:1, v:v, wherein, the polar aprotic solvent is dimethyl sulfoxide and N,N-dimethylmethane The mixed solvent of amide, dimethyl sulfoxide:N,N-dimethylformamide=1:2, v:v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) were added In a 500 mL high-pressure reaction kettle, the air in the reaction kettle was replaced with 3 MPa nitrogen three times, then filled with 3 MPa nitrogen, heated and stirred at 180 ° C for 4 h, rapidly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product, acetyl The yield of propionic acid was 32.3%, the yield of 5-hydroxymethylfurfural was 0.6%, and the yield of furfural was 3.7%.

Example 17

Add 4g sulfamic acid, 50mL N,N-dimethylformamide/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into 500mL high pressure In the reaction kettle, the air in the reaction kettle was replaced with 3MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 4h, rapidly cooled to room temperature, slowly depressurized, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product, levulinic acid The yield was 48.5%, and 5-hydroxymethylfurfural and furfural were hardly detected.

Example 18

A mixture of 4g nickel sulfamate and sodium sulfamate, 50mL N,N-dimethylformamide/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) was added into a 500mL autoclave, the air in the reactor was replaced with 3MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 4h, rapidly cooled to room temperature, slowly depressurized, filtered, and the filtrate was collected and decompressed. Distillation gave the product in 18.9% yield of levulinic acid with almost no detectable 5-hydroxymethylfurfural and furfural.

Example 19

A mixture of 4 g p-toluenesulfonic acid, sodium sulfamate and sulfamic acid, 50 mL N,N-dimethylformamide/water mixture (25:1, v:v) and 10 g holocellulose model compound (containing 6g of cellulose and 4g of xylan) were added to a 500mL high-pressure reactor, the air in the reactor was replaced with 3MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 4h, quickly cooled to room temperature, slowly released, filtered, and collected. The filtrate was distilled under reduced pressure to obtain the product. The yield of levulinic acid was 33.8%, and 5-hydroxymethylfurfural and furfural were hardly detected.

Example 20

4g sulfamic acid, 50mL composite solvent (polar aprotic solvent/water mixed solution, 25:1, v:v, wherein, the polar aprotic solvent is the mixed solvent of 2-methyltetrahydrofuran and γ-valerolactone. , 2-methyltetrahydrofuran: tetrahydrofuran=1:2, v:v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) were added into 500mL autoclave, and the reactor was replaced with 3MPa nitrogen Inner air for three times, then filled with 3MPa nitrogen, heated and stirred at 180°C for 4 hours, rapidly cooled to room temperature, slowly depressurized, filtered, collected the filtrate, distilled under reduced pressure to obtain the product, the yield of 5-hydroxymethylfurfural was 31.7%, furfural The yield was 21.6% and almost no levulinic acid was detected.

Example 21

4g sulfamic acid, 50mL composite solvent (polar aprotic solvent/water mixed solution, 25:1, v:v, wherein, the polar aprotic solvent is the mixture of methyl isobutyl ketone and γ-valerolactone. Solvent, methyl isobutyl ketone: γ-valerolactone = 1:2, v:v) and 10 g holocellulose model compound (containing 8 g cellulose and 2 g xylan) were added to a 500 mL autoclave, with 3 MPa Nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 °C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of 5-hydroxymethylfurfural was 18.9%, furfural yield was 28.7%, and almost no levulinic acid was detected.

Example 22

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (10:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 37.6%, 5 -Hydroxymethylfurfural yield was 25.1% with almost no levulinic acid detected.

Example 23

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (50:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 21.2%, 5 -Hydroxymethylfurfural yield was 18.4% with almost no detectable levulinic acid.

Example 24

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 6g cellulose and 4g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 180 ° C for 10 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 67.4%, 5 - The yield of hydroxymethylfurfural was 32.4%, and almost no levulinic acid was detected.

Example 25

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 5g cellulose and 5g xylan) into a 500mL autoclave, use The air in the reaction kettle was replaced by 3MPa nitrogen three times, then filled with 3MPa nitrogen, heated and stirred at 200°C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product, the yield of 5-hydroxymethylfurfural. was 30.2%, furfural yield was 50.8%, and almost no levulinic acid was detected.

Example 26

Add 4g sulfamic acid, 50mL γ-valerolactone/water mixture (25:1, v:v) and 10g holocellulose model compound (containing 5g cellulose and 5g xylan) into a 500mL autoclave, use 3MPa nitrogen replaced the air in the reaction kettle three times, then filled with 3MPa nitrogen, heated and stirred at 120 °C for 4 hours, quickly cooled to room temperature, slowly relieved pressure, filtered, collected the filtrate, and distilled under reduced pressure to obtain the product. The yield of furfural was 35.7%, almost 5-Hydroxymethylfurfural and levulinic acid were not detected.

Comparative Example 1

Except that the p-aminobenzenesulfonic acid in Example 1 is replaced with sulfuric acid, other steps are the same as those in Example 1. After testing, the yield of furfural in the product was 19.6%, and 5-hydroxymethylfurfural and levulinic acid were hardly detected.

Comparative Example 2

Except that the γ-valerolactone in Example 1 was replaced with ethanol, other steps were the same as those in Example 1. After testing, the yield of furfural in the product was 3.6%, and the yield of 5-hydroxymethylfurfural and levulinic acid were hardly detected.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of patent protection of the present invention.

Claims (6)

1. a method for preparing bio-based chemicals with lignocellulosic biomass as raw material, is characterized in that, comprises the following steps: Mixing the polar aprotic solvent and water in a volume ratio of 10 to 50:1 to obtain a composite solvent; Add the raw materials of holocellulose and the organic acid catalyst into the composite solvent, hydrolyze the reaction, separate and purify to obtain the bio-based chemicals; Wherein, the holocellulose raw material comprises cellulose and hemicellulose; The polar aprotic solvent is N,N-dimethylformamide, and the bio-based chemical is levulinic acid; The organic acid catalyst includes at least one of sulfamic acid, p-sulfamic acid, cobalt p-toluenesulfonic acid sulfamate, nickel sulfamate, ammonium sulfamate and sodium sulfamate. 2. the method for preparing bio-based chemicals with lignocellulosic biomass as raw material as claimed in claim 1, it is characterized in that, the monocellulose raw material and organic acid catalyst are added in composite solvent, hydrolysis reaction, separation and purification In the step of obtaining bio-based chemicals, the holocellulose raw material includes at least one of holocellulose and holocellulose model compound, and the holocellulose model compound is a mixture of cellulose and hemicellulose. 3. The method for preparing bio-based chemicals from lignocellulosic biomass as claimed in claim 2, wherein in the holocellulose model compound, the cellulose and the hemicellulose are The mass ratio is 1~4:1. 4. the method for preparing bio-based chemicals with lignocellulosic biomass as raw material as claimed in claim 1, it is characterized in that, the monocellulose raw material and organic acid catalyst are added in composite solvent, hydrolysis reaction, separation and purification In the step of obtaining the bio-based chemicals, the weight ratio of the organic acid catalyst and the holocellulose raw material is 1:2-10. 5. the method for preparing bio-based chemicals with lignocellulosic biomass as a raw material as claimed in claim 1, is characterized in that, adding the monocellulose raw material and organic acid catalyst to the composite solvent, hydrolysis reaction, separation and purification In the step of obtaining the bio-based chemicals, the conditions of the hydrolysis reaction are that the temperature is 120-200° C. and the time is 1-10 h. 6. the method for preparing bio-based chemicals with lignocellulosic biomass as a raw material as claimed in claim 1, is characterized in that, the monocellulose raw material and organic acid catalyst are added in composite solvent, hydrolysis reaction, separation and purification In the step of obtaining a bio-based chemical, the hydrolysis reaction is carried out under a nitrogen atmosphere.