Method for efficiently preparing furfural and glucose from forest grass biomass

Abstract

The invention discloses a method for efficiently preparing furfural and glucose from forest grass biomass. The method comprises the following steps: mixing a forest grass biomass raw material, a molten salt hydrate and an organic solvent, and carrying out a pretreatment reaction to obtain a furfural-containing pretreatment solution and pretreatment residues; mixing the pretreated residues, sulfuric acid and molten salt hydrate, and then performing hydrolysis reaction to obtain hydrolysate containing glucose; the method for preparing furfural and glucose from forest grass biomass provided by the invention is simple, convenient to operate, environment-friendly, short in time, high in yield, economical and efficient, and has a wide industrial application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass refining, and specifically relates to a method for efficiently preparing furfural and glucose from forest and grass biomass. Background Art

[0002] As the world's most abundant renewable resource, the high value of forest and grass biomass is the focus of biorefining and green chemistry research. Cellulose and hemicellulose are important components of forest and grass biomass (accounting for 60-80% of the total content), which can be hydrolyzed and converted into various multifunctional monosaccharides (xylose, glucose, mannose, arabinose) and biomass-based platform compounds (furfural, 5-hydroxymethylfurfural, levulinic acid). Among them, furfural, as a very important intermediate in fine chemicals and polymer industries, is widely used in resins, plastics, pesticides, green solvents, fuel additives and other fine chemical products; glucose can be used in medicine, food, microbial fermentation, leather and fuel, etc. Therefore, the study of the catalytic conversion of forest and grass biomass into furfural and glucose has important practical and strategic significance.

[0003] At present, there are two main methods for synthesizing furfural and glucose using forest and grass biomass as raw materials: (1) direct one-step chemical catalysis to obtain furfural and glucose; (2) pretreatment to achieve component separation: hemicellulose is converted into xylose, xylose is chemically catalyzed into furfural; the separated cellulose is converted into glucose through enzymatic hydrolysis. In the actual application of the direct one-step chemical catalysis method, a large amount of cellulose in forest and grass biomass is degraded into by-products (humus), and the glucose yield obtained is low, which limits its industrial application. For example, Li et al. (2023) used sulfuric acid as a catalyst, dichloromethane and LiBr·3H2O as solvents to catalyze corn stalk into furfural and glucose in one step, and obtained only 58.9% glucose yield and 72.5% furfural yield under the conditions of 120℃ and 90min (Y.Li, LLSun, DM Cao, et al., One-step conversion of corn stalk to glucose and furfural in molten salt hydrate / organic solvent biphasic system, Bioresource Technology, 386 (2023) 129520). The research on the separation of components after pretreatment and further synthesis of furfural and glucose has long been widely concerned by researchers at home and abroad due to its wide applicability and high yield of target products. For example, Zhang Sitong et al. pretreated corn stalks with ethylenediamine and sodium carbonate solution in Chinese patent CN118086423A, and obtained pretreated residues (cellulose content 65.1%, hemicellulose content 22.3%, lignin removal rate 85.2%) under the pretreatment conditions of 80°C and 4h. The pretreated residues were then enzymatically hydrolyzed by cellulase for 72h to obtain a glucose yield of 92.3%.Cheng et al. (2023) pretreated bamboo with a PTSA-DES / GVL solvent system and obtained a furfural yield of 68.6% and a pretreatment residue (90.0% cellulose retention rate, 89.1% lignin removal rate, and 100% hemicellulose removal rate) at 110°C for 1 h. The pretreatment residue was then enzymatically hydrolyzed by cellulase for 72 h to achieve a glucose yield of 91.2% (JYCheng, C.Huang, YNZhan, et al., Anovel mineral-acid freebiphasic deep eutectic solvent / γ-valerolactone system for furfural production and boosting the enzymatic hydrolysis of lignocellulosic biomass, Bioresource Technology, 387(2023)129653). Although the above research methods show good results in preparing glucose or furfural, these methods require a long enzymatic reaction time and the use of expensive cellulase reagents, which increases the preparation cost and is not conducive to industrial production. Therefore, it is urgent to develop an environmentally friendly, simple to operate, and low-cost production technology to achieve an industrial method for preparing furfural and glucose. Summary of the invention

[0004] In view of the problems and shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for efficiently preparing furfural and glucose from forest and grass biomass; the method of the present invention has a simple process, a green and environmentally friendly catalytic system, mild reaction conditions, a short reaction time, and a high yield of the target product.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A method for efficiently preparing furfural and glucose from forest and grass biomass, comprising the following steps:

[0007] (1) mixing forest and grass biomass raw materials, molten salt hydrate and an organic solvent and subjecting them to a pretreatment reaction to obtain a pretreatment liquid containing furfural and a pretreatment residue;

[0008] (2) The pretreatment residue of step (1), sulfuric acid and molten salt hydrate are mixed and then hydrolyzed to obtain a hydrolyzate containing glucose.

[0009] Furthermore, in step (1), the forest and grass biomass raw material is at least one of wheat straw, corn straw and eucalyptus;

[0010] Furthermore, in step (1), the ratio of the mass of the forest and grass biomass raw material to the total volume of the molten salt hydrate and the organic solvent is 1:10-25 g / mL.

[0011] Furthermore, in step (1), the molten salt hydrate is at least one of ZnCl2, LiCl, CaCl2, AlCl3, LiBr and water;

[0012] Furthermore, in step (1), the concentration of the molten salt hydrate is 40 to 70 wt%.

[0013] Furthermore, in step (1), the organic solvent is at least one of γ-valerolactone, dimethyl sulfoxide, and methyl isobutyl ketone.

[0014] Furthermore, in step (1), the volume ratio of the molten salt hydrate to the organic solvent is 0.25 to 4:1.

[0015] Furthermore, in step (1), the temperature of the pretreatment reaction is 120 to 150° C., and the time of the pretreatment reaction is 10 to 120 min.

[0016] Further, in step (2), the molten salt hydrate is at least one of ZnCl2, LiCl, CaCl2, AlCl3, LiBr and water;

[0017] Furthermore, in step (2), the concentration of the molten salt hydrate is 40 to 70 wt%.

[0018] Furthermore, in step (2), the mass concentration of the sulfuric acid is above 95%;

[0019] Furthermore, in step (2), the usage ratio of the pretreatment residue, sulfuric acid and molten salt hydrate is 1: 0.01-0.05: 50-150 g / moL / mL.

[0020] Furthermore, in step (2), the temperature of the hydrolysis reaction is 70 to 100° C., and the time of the hydrolysis reaction is 10 to 30 minutes.

[0021] Furthermore, in step (1), the yield of furfural is 1.8% to 67.3%; the retention rate of cellulose in the pretreatment residue is 92.0% to 99.6%, the removal rate of hemicellulose is 75.2% to 95.5%, and the removal rate of lignin is 44.9% to 80.1%;

[0022] Furthermore, in step (2), the yield of glucose is 42.6% to 93.8%.

[0023] The invention can selectively obtain a pretreatment liquid with a furfural yield of 67.3% and a pretreatment residue with a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; and can selectively hydrolyze to obtain a hydrolyzate with a glucose yield of 93.8%.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The present invention provides a method for preparing furfural and glucose, thereby achieving high yields of furfural and glucose from catalytic forest and grass biomass.

[0026] (2) The present invention uses molten salt hydrate as a pretreatment and catalytic reagent, which is cheap and readily available, has a good pretreatment and separation effect, high catalytic activity, and mild reaction conditions.

[0027] (3) The present invention utilizes γ-valerolactone as an organic solvent to obtain the product furfural in high yield and the pretreatment residues for efficiently removing hemicellulose and lignin. The solvent has the advantages of being green, easy to store, and safe.

[0028] (4) The present invention uses the molten salt hydrate chemical catalysis method to achieve a high furfural yield while achieving a high glucose yield, reducing the generation of by-products, and having a high economic benefit.

[0029] (5) The catalytic system of the present invention is green, has mild reaction conditions, high economic benefits, simple process operation, and has industrial application prospects. DETAILED DESCRIPTION

[0030] The technical solutions and effects of the present invention are further described below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0031] The yield was calculated by high performance liquid chromatography (HPLC) according to the following formula:

[0032] (1) Furfural yield = (molar amount of furfural in pretreatment solution / molar amount of hemicellulose in forest and grass biomass) × 100%;

[0033] (2) Glucose yield = (molar amount of glucose in the hydrolyzate / molar amount of cellulose in the pretreatment residue) × 100%.

[0034] Example 1

[0035] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 93.8%.

[0036] Example 2

[0037] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: forest and grass biomass eucalyptus, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of eucalyptus to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 56.8%, a cellulose retention rate of 93.5%, a hemicellulose removal rate of 90.5% and a lignin removal rate of 60.3%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 83.1%.

[0038] Example 3

[0039] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, LiBr 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of LiBr 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment is performed at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 3.7%, a cellulose retention rate of 93.2%, a hemicellulose removal rate of 79.7% and a lignin removal rate of 80.1%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 88.6%.

[0040] Example 4

[0041] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate to γ-valerolactone is 0.43:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 56.8%, a cellulose retention rate of 99.6%, a hemicellulose removal rate of 83.8% and a lignin removal rate of 70.1%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 57.9%.

[0042] Example 5

[0043] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 150°C for 40min to obtain a pretreatment liquid with a furfural yield of 58.6%, a cellulose retention rate of 95.8%, a hemicellulose removal rate of 95.5% and a lignin removal rate of 62.0%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 78.6%.

[0044] Example 6

[0045] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 20min to obtain a pretreatment liquid with a furfural yield of 59.0%, a cellulose retention rate of 99.3%, a hemicellulose removal rate of 85.4% and a lignin removal rate of 65.6%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 83.6%.

[0046] Example 7

[0047] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, ZnCl2 60wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 81.7%.

[0048] Example 8

[0049] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.045:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 67.6%.

[0050] Example 9

[0051] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 90°C for 20min to obtain a hydrolyzate with a glucose yield of 78.9%.

[0052] Example 10

[0053] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 15min to obtain a hydrolyzate with a glucose yield of 72.5%.

[0054] Comparative Example 1

[0055] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate, γ-valerolactone and concentrated sulfuric acid (98wt%) are mixed in sequence and added into a reactor without pressure setting, the dosage ratio of wheat straw, sulfuric acid, molten salt hydrate and γ-valerolactone is 1:0.006:20 (g / moL / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; react at 140°C for 40min, obtain a reaction solution with a furfural yield of 30.1%, a glucose yield of 26.9%, a cellulose retention rate of 46.3%, a hemicellulose removal rate of 95.7% and a lignin removal rate of 82.5% as reaction residue.

[0056] Comparative Example 2

[0057] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, LiCl 40wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of LiCl 40wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment is performed at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 1.8%, a cellulose retention rate of 92.0%, a hemicellulose removal rate of 75.2% and a lignin removal rate of 48.9%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 45.8%.

[0058] Comparative Example 3

[0059] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, CaCl2 50wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of CaCl2 50wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 14.5%, a cellulose retention rate of 94.3%, a hemicellulose removal rate of 76.7% and a lignin removal rate of 44.9%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 39.1%.

[0060] Comparative Example 4

[0061] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, AlCl3 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of AlCl3 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 45.3%, a cellulose retention rate of 32.2%, a hemicellulose removal rate of 89.1% and a lignin removal rate of 65.1%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 12.3%.

[0062] Comparative Example 5

[0063] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and dimethyl sulfoxide are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and dimethyl sulfoxide is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and dimethyl sulfoxide is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 35.6%, a cellulose retention rate of 76.2%, a hemicellulose removal rate of 86.7% and a lignin removal rate of 56.3%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 21.3%.

[0064] Comparative Example 6

[0065] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: forest and grass biomass wheat straw, ZnCl2 60wt% molten salt hydrate and methyl isobutyl ketone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and methyl isobutyl ketone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and methyl isobutyl ketone is 1:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 18.6%, a cellulose retention rate of 81.6%, a hemicellulose removal rate of 78.6% and a lignin removal rate of 67.3%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 46.8%.

[0066] Comparative Example 7

[0067] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate to γ-valerolactone is 0.25:1; pretreatment at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 43.2%, a cellulose retention rate of 97.8%, a hemicellulose removal rate of 78.0% and a lignin removal rate of 54.1%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 51.3%.

[0068] Comparative Example 8

[0069] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment is performed at 150°C for 120min to obtain a pretreatment liquid with a furfural yield of 44.6%, a cellulose retention rate of 78.1%, a hemicellulose removal rate of 98.9% and a lignin removal rate of 34.7%; then the pretreatment residue, ZnCl2 65wt% molten salt hydrate and concentrated sulfuric acid (98wt%) were mixed in sequence and added into the reactor. The dosage ratio of pretreatment residue, sulfuric acid and molten salt hydrate was 1:0.03:100 (g / moL / mL). The hydrolysis reaction was carried out at 80°C for 20min to obtain a hydrolyzate with a glucose yield of 41.7%.

[0070] Comparative Example 9

[0071] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: forest and grass biomass wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); the volume ratio of ZnCl2 60wt% molten salt hydrate to γ-valerolactone is 1:1; pretreatment is performed at 140°C for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue and ZnCl2 65wt% molten salt hydrate are mixed in sequence and added into a reactor, the solid-liquid ratio of the pretreatment residue to the molten salt hydrate is 1:100 (g / mL), hydrolysis reaction is performed at 80°C for 20min, and a hydrolyzate with a glucose yield of 26.3% is obtained.

[0072] Comparative Example 10

[0073] A method for efficiently preparing furfural and glucose from forest and grass biomass, the specific steps are as follows: forest and grass biomass wheat straw, ZnCl2 60wt% molten salt hydrate and γ-valerolactone are mixed in sequence and added into a reactor without pressure setting, the solid-liquid ratio of wheat straw to molten salt hydrate and γ-valerolactone is 1:20 (g / mL); ZnCl2 The volume ratio of 60wt% molten salt hydrate and γ-valerolactone is 1:1; pretreatment at 140℃ for 40min to obtain a pretreatment liquid with a furfural yield of 67.3%, a cellulose retention rate of 98.5%, a hemicellulose removal rate of 93.5% and a lignin removal rate of 71.2%; then the pretreatment residue, deionized water and concentrated sulfuric acid (98wt%) are mixed in sequence and added to the reactor, the dosage ratio of the pretreatment residue, sulfuric acid and deionized water is 1:0.03:100 (g / moL / mL), and the hydrolysis reaction is carried out at 80℃ for 20min to obtain a hydrolyzate with a glucose yield of 6.2%.

[0074] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for efficiently preparing furfural and glucose from forest and grass biomass, characterized in that: The following steps are involved: (1) mixing forest and grass biomass raw materials, molten salt hydrate and an organic solvent and subjecting them to a pretreatment reaction to obtain a pretreatment liquid containing furfural and a pretreatment residue; (2) The pretreatment residue of step (1), sulfuric acid and molten salt hydrate are mixed and then hydrolyzed to obtain a hydrolyzate containing glucose.

2. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the forest and grass biomass raw material is at least one of wheat straw, corn straw and eucalyptus; In step (1), the ratio of the mass of the forest and grass biomass raw material to the total volume of the molten salt hydrate and the organic solvent is 1:10-25 g / mL.

3. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the molten salt hydrate is at least one of ZnCl2, LiCl, CaCl2, AlCl3, LiBr and water; In step (1), the concentration of the molten salt hydrate is 40 to 70 wt%.

4. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the organic solvent is at least one of γ-valerolactone, dimethyl sulfoxide, and methyl isobutyl ketone.

5. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the volume ratio of the molten salt hydrate to the organic solvent is 0.25 to 4:

1.

6. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the temperature of the pretreatment reaction is 120 to 150° C., and the time of the pretreatment reaction is 10 to 120 minutes.

7. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (2), the molten salt hydrate is at least one of ZnCl2, LiCl, CaCl2, AlCl3, LiBr and water; In step (2), the concentration of the molten salt hydrate is 40 to 70 wt%.

8. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (2), the mass concentration of the sulfuric acid is above 95%; In step (2), the dosage ratio of the pretreatment residue, sulfuric acid and molten salt hydrate is 1: 0.01-0.05: 50-150 g / moL / mL.

9. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (2), the temperature of the hydrolysis reaction is 70 to 100° C., and the time of the hydrolysis reaction is 10 to 30 minutes.

10. The method for efficiently preparing furfural and glucose from forest and grass biomass according to claim 1, characterized in that: In step (1), the yield of furfural is 1.8% to 67.3%; the retention rate of cellulose in the pretreatment residue is 92.0% to 99.6%, the removal rate of hemicellulose is 75.2% to 95.5%, and the removal rate of lignin is 44.9% to 80.1%; In step (2), the yield of glucose is 42.6% to 93.8%.