A mixed solvent for quickly and efficiently dissolving all components of lignocellulose and a dissolution method

Abstract

The present invention discloses a mixed solvent system capable of rapidly and efficiently dissolving all components of lignocellulose, and a dissolution method for dissolving all components of lignocellulose using the mixed solvent system. The mixed solvent system is composed of a mixture of an ionic liquid, ethanolamine, and an organic superbase. Through the synergistic effect of the three components, the ethanolamine dissociates the lignin attached to the carbohydrates, and the organic superbase then further penetrates and swells the cellulose, deconstructing the lignocellulose and promoting the rapid and efficient dissolution of the various components of the lignocellulose in the ionic liquid. The mixed solvent provided by the present invention solves the problems of low dissolution efficiency of all components of lignocellulose in existing solvent systems, high dissolution conditions, and complex dissolution processes.

Description

Technical Field

[0001] The present invention belongs to the field of biomass refining, and in particular relates to a mixed solvent system capable of quickly and efficiently dissolving all components of lignocellulose and a dissolution method for dissolving all components of lignocellulose using the mixed solvent system. Background Art

[0002] Lignocellulosic biomass, a rich renewable resource, is primarily composed of cellulose (35%-50%), hemicellulose (20%-40%), and lignin (15%-25%), and exhibits significant complexity and rigidity. Selective production of biomass energy, chemicals, and materials using lignocellulose as a raw material through fractionation, dissolution regeneration, modification, saccharification, and catalysis has become a key focus in developing a circular economy. Lignocellulosic biomass is typically processed by solution processing, where lignin forms a lignin-carbohydrate complex with hemicellulose through covalent bonds and is then coated on the cellulose surface through strong hydrogen bonds, forming a naturally dense structure. Furthermore, the highly crystalline structure formed by extensive hydrogen bonding in cellulose further increases the difficulty of dissolving all lignocellulose components in common solvents, limiting the potential for utilization of all lignocellulose components.

[0003] At present, people have successfully designed a solvent system that dissolves all components of lignocellulose. Chinese patent CN105418943A discloses that lignocellulose can be dissolved in a hydrated solution of N-methylmorpholine-N-oxide. This process requires the lignocellulose to be pretreated with a high temperature of a polyol and subjected to a high-intensity mechanical refining and rolling treatment, but it can only form a lignocellulose solution with a concentration of 1%. Chinese patent CN103147331A discloses a method of treating lignocellulose with a mixed solvent of multiple imidazole ionic liquids at 70-120°C for 2-6 hours, which is then used to extract cellulose. However, the mixed solvent of multiple ionic liquids cannot completely dissolve all components of lignocellulose. Chinese patent CN105295070A uses a mixed solution of polyol-inorganic acid or organic acid-inorganic acid to pretreat lignocellulose with high temperature swelling, which is then mechanically squeezed and dissolved in the mixed solvent. Chinese patent CN105001429A discloses a method for dissolving lignocellulose using sulfuric acid-hydrogen peroxide-ethanol-water as a solvent. This method requires high temperatures and consumes a lot of energy. The subsequent hydrolysis products are mostly chemicals such as monosaccharides and furan compounds, which have significant structural variations, limiting the application scope of the lignocellulose solution. Although some success has been achieved in dissolving all components of lignocellulose, several issues remain, including low dissolution efficiency, complex and energy-intensive dissolution processes, and a narrow application scope for the resulting lignocellulose solution.

[0004] Therefore, it is particularly important to find a solvent that can dissolve all components of lignocellulose with low cost, simple and mild process, wide raw material applicability and high dissolution efficiency. Summary of the Invention

[0005] In response to the problems of the above-mentioned prior art, the present invention provides a mixed solvent and dissolution method for rapidly and efficiently dissolving all components of lignocellulose. This mixed solvent is composed of an ionic liquid, ethanolamine, and an organic superbase. Through the synergistic effect of the three components, the ethanolamine dissociates the lignin attached to the carbohydrates, and the organic superbase then further penetrates and swells the cellulose, deconstructing the lignocellulose and promoting the rapid and efficient dissolution of all components of the lignocellulose in the ionic liquid. The mixed solvent provided by the present invention solves the problems of low dissolution efficiency of existing solvent systems for dissolving all components of lignocellulose, high dissolution conditions, and complex dissolution processes.

[0006] To achieve the above objectives, according to the first aspect of the present invention, one object of the present invention is to provide a fast and efficient mixed solvent for dissolving all components of lignocellulose, wherein the mixed solvent system is composed of an ionic liquid, ethanolamine and an organic superbase.

[0007] Wherein, the ionic liquid is selected from imidazole ionic liquids.

[0008] The organic superbase is selected from one of 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]undec-7-ene and 1,1,3,3-tetramethylguanidine.

[0009] The molar ratio of the ionic liquid, ethanolamine and organic superbase is 10-0.18:1:1.

[0010] Preferably, the ionic liquid is selected from one of 1-ethyl-3-methylimidazolium acetate, 1-propyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium chloride, 1-propyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, and 1-allyl-3-methylimidazolium chloride.

[0011] Preferably, the molar ratio of the ionic liquid, ethanolamine and organic superbase is 5-0.2:1:1, more preferably, the molar ratio is 5:1:1, 4:1:1, 3:1:1, 2:1:1, 1:1:1, 1 / 2:1:1, 1 / 3:1:1, 1 / 4:1:1 or 1 / 5:1:1.

[0012] The preparation method of the mixed solvent according to the present invention is not particularly limited. For example, it can be prepared by stirring and mixing. For example, the three components are stirred at 50° C. for 5-30 minutes to form a uniform and transparent mixed solvent. The stirring speed is 300 r / min.

[0013] According to the second aspect of the present invention, another object of the present invention is to provide a method for dissolving all components of lignocellulose, which comprises:

[0014] (1) mechanically refining and pulverizing the dried lignocellulose raw material in a planetary ball mill to form lignocellulose raw material particles;

[0015] (2) Dispersing the lignocellulose powder obtained in step (1) in a mixed solvent, stirring continuously at 70-90° C. for 0.5 to 10 hours at a stirring speed of 200 to 1000 r / min, until the lignocellulose powder is completely dissolved to obtain a uniform, stable, clear and transparent lignocellulose solution.

[0016] Preferably, the lignocellulosic raw material is selected from one of the grass family (e.g., sugarcane bagasse, sorghum straw, wheat straw, rice straw, corn cobs, bamboo, and miscanthus), broad-leaved wood (e.g., poplar wood powder), and coniferous wood (e.g., radiata pine wood powder). More preferably, the lignocellulosic raw material is selected from one of the group consisting of sugarcane bagasse, sorghum straw, wheat straw, rice straw, corn cobs, bamboo, and miscanthus.

[0017] More preferably, the ball milling treatment in step (1) is carried out as follows: 10.0 g of lignocellulose powder passed through a 60-80 mesh sieve and 70 zirconium dioxide balls with a diameter of 10 mm are weighed and added to the zirconium dioxide tank of a planetary ball mill, and ball milled at a speed of 400 r / min for 4 hours, with a ball milling interval of 5 minutes and a rest time of 5 minutes after each ball milling.

[0018] Preferably, the dissolution stirring speed in step (2) is 400 to 800 r / min, more preferably 500 r / min.

[0019] Preferably, the stirring time in step (2) is 1-5 hours.

[0020] According to the third aspect of the present invention, another object of the present invention is to provide a use of the high-concentration lignocellulose full-component solution prepared by the mixed solvent system according to the present invention in the preparation of membrane materials, spinning materials and gel materials.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The mixed solvent according to the present invention is composed of reagents commonly used in the art, is simple to prepare, and has strong dissolving power. This is mainly due to the synergistic effect between the components in the mixed solvent, namely, ethanolamine dissociates lignin attached to carbohydrates, and then the organic superbase further penetrates and swells cellulose, deconstructing the lignocellulose, thereby promoting the dissolution of the various components of the lignocellulose in the ionic liquid.

[0023] 2. According to the dissolution method of the present invention, there is no need to chemically pretreat the lignocellulose. Instead, the lignocellulose can be directly ball-milled and then added to the mixed solvent to achieve complete dissolution of all components. The operation is simple and the process cost is low.

[0024] 3. The mixed solvent of the present invention can dissolve a wide range of wood cellulose materials, including grasses (bagasse, sorghum straw, wheat straw, rice straw, corn cobs, bamboo, and Miscanthus), broad-leaved wood (white poplar wood powder), and coniferous wood (radiata pine wood powder).

[0025] 4. The present invention has low requirements for dissolution temperature and does not require excessively high temperature and pressure. All components of lignocellulose can be dissolved in a closed environment under mild conditions (<100°C), obtaining a lignocellulose solution with high solubility, uniformity, stability, clarity and transparency. The conditions are easy to control and safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 is a photo of a lignocellulose (bagasse) solution having different solubility in different solvents according to Example 1, wherein Figure 1 a is 1-ethyl-3-methylimidazolium acetate-lignocellulose solution, Figure 1 b is 1-ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1)-lignocellulose solution.

[0028] Figure 2 The polarized light microscope photographs of 20 mg of lignocellulose (bagasse) completely dissolved in different solvents according to Example 1, wherein Figure 2 a is 1-ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1) solvent, Figure 2b is 1-ethyl-3-methylimidazolium acetate solvent.

[0029] Figure 3 is the solubility of different lignocellulosic raw materials in a mixed solvent of 1-ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1) at 90°C. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are merely preferred examples for illustrative purposes and are not intended to limit the scope of the present invention. It should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0031] The fast and efficient mixed solvent for dissolving all components of lignocellulose according to the present invention is mixed with ionic liquid, ethanolamine and organic super alkali, and the three components are matched and act synergistically to achieve the complete dissolution of all components of lignocellulose, wherein ethanolamine dissociates the lignin connected to the carbohydrate, and then the organic super alkali further penetrates and swells the cellulose, deconstructing the lignocellulose, and the ionic liquid plays a role in quickly and efficiently dissolving the various components of lignocellulose, ultimately forming a uniform, stable, clear and transparent true solution. As mentioned in the background technology part, although there are also systems for achieving the dissolution of all components of lignocellulose in the prior art, there are often shortcomings such as complex processes and high energy consumption. In particular, some systems (for example, ionic liquids) do not achieve the "real" dissolution of the various components of lignocellulose, and what is formed is often a suspension, i.e., a pseudo-solution state. In addition, although other systems (for example, NMMO solution, LiCl / DMSO solution) achieve the "real" dissolution of the various components of lignocellulose, they can often only dissolve a very small amount of lignocellulose. The present invention can achieve complete dissolution of various components of lignocellulose under mild conditions to form a uniform, stable, clear and transparent true solution; at the same time, it has strong complete dissolving ability and can dissolve a large amount of lignocellulose.

[0032] The molar ratio of the ionic liquid, ethanolamine, and organic superbase in the mixed solvent of the present invention is 10-0.18:1:1, preferably 5-0.2:1:1, more preferably 5:1:1, 4:1:1, 3:1:1, 2:1:1, 1:1:1, 1 / 2:1:1, 1 / 3:1:1, 1 / 4:1:1, or 1 / 5:1:1. Only when the ratio of the three components is controlled within the above range can all components of the lignocellulose be effectively dissolved.

[0033] Throughout this document, all features or conditions defined as numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values within those ranges, particularly integer values. For example, a description of a range "1 to 8" should be considered to specifically disclose all possible subranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, and so forth, particularly those defined by all integer values, and should be considered to specifically disclose individual values within those ranges such as 1, 2, 3, 4, 5, 6, 7, and 8. Unless otherwise indicated, the foregoing interpretation applies to all of the present disclosure, regardless of whether the ranges are comprehensive or not.

[0034] If a quantity or other value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that all ranges consisting of any upper limit or preferred value of the range and any lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, when a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0035] In this document, numerical values should be understood to have the accuracy of the number of significant digits of the numerical value, provided that the purpose of the invention can be achieved. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0036] In addition, unless otherwise specified, the reagents and solvents disclosed below were purchased from Shanghai Aladdin Biochemical; ball milling experiments were performed using the XQM-4A series from Changsha Tianchuang Powder Technology Co., Ltd.; and polarizing microscope images were taken using the EP50 series from Olympus.

[0037] The following examples are merely examples of embodiments of the present invention and do not constitute any limitation thereto. Those skilled in the art will appreciate that modifications without departing from the spirit and scope of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0038] The lignocellulosic raw material used in the following examples was first dried and then subjected to a high-intensity mechanical fine pulverization treatment in a planetary ball mill as follows to form lignocellulosic raw material particles: 10.0 g of lignocellulosic raw material powder passed through a 60-80 mesh sieve and 70 zirconium dioxide balls with a diameter of 10 mm were weighed and added to the zirconium dioxide tank of the planetary ball mill. The mixture was ball milled at a speed of 400 r / min for 4 hours, with a ball milling interval of 5 minutes and a rest time of 5 minutes after each ball milling.

[0039] Example 1

[0040] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 20 mg, 40 mg, 60 mg, 80 mg and 100 mg of ball-milled sugarcane bagasse, respectively, place it in a 90°C oil bath and continue stirring for 1, 2, 4, 5 and 5 hours at a speed of 500 r / min to obtain uniform, stable, clear and transparent lignocellulose solutions with concentrations of 1%, 2%, 3%, 4% and 5%, respectively.

[0041] Figure 1 is a photo of a lignocellulose (bagasse) solution with different solubility according to this embodiment, wherein Figure 1 a is 1-ethyl-3-methylimidazolium acetate-lignocellulose solution, Figure 1 b is 1-ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1)-lignocellulose solution. Figure 1 As can be seen in Figure b, the mixed solvent according to the present invention can effectively dissolve all components of lignocellulose and form a true solution. Even at a high lignocellulose concentration, the black lines on the background plate in the figure are still clearly visible, and there is no astigmatism, indicating that a true solution is formed. Figure 1 a shows that in a single component of a conventional ionic liquid (1-ethyl-3-methylimidazolium acetate), complete solubility can only be achieved at a 1% concentration of lignocellulose.

[0042] Figure 2 Polarized microscope photos of the complete dissolution process of 20 mg of lignocellulose (bagasse) in different solvents according to this embodiment ( Figure 2 a. 1-Ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1) solvent; Figure 2 b. 1-ethyl-3-methylimidazolium acetate solvent). Figure 2As can be seen in a, a completely black background was shown in the polarizing microscope at 50 minutes, indicating that 20 mg of lignocellulose (bagasse) can be quickly and completely dissolved in the mixed solvent (1-ethyl-3-methylimidazolium acetate / ethanolamine / 1,5-diazabicyclo[4.3.0]-5-nonene (1:1:1)) of the present invention. Figure 2 b shows that it takes 300 min to completely dissolve 1% of lignocellulose in a single component of a traditional ionic liquid (1-ethyl-3-methylimidazolium acetate).

[0043] Example 2

[0044] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 190 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 9.5 g / 100 g.

[0045] Example 3

[0046] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 90 mg of ball-milled sugarcane bagasse and place it in a 70 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 4.5 g / 100 g.

[0047] Example 4

[0048] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazole acetate, ethanolamine and 1,8-diazabicyclo[5.4.0]undec-7-ene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 172 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 8.6 g / 100 g.

[0049] Example 5

[0050] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,1,3,3-tetramethylguanidine in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 140 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 7.0 g / 100 g.

[0051] Example 6

[0052] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:3:3) and add it to a 10 mL glass bottle. Add 130 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 6.5 g / 100 g.

[0053] Example 7

[0054] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 3:1:1) and add it to a 10 mL glass bottle. Add 148 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 7.4 g / 100 g.

[0055] Example 8

[0056] 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:6:6) was added to a 10 mL glass bottle, 20 mg of ball-milled sugarcane bagasse was added, and the mixture was placed in a 90 °C oil bath and stirred continuously for 5 h at a speed of 500 r / min. However, a uniform, stable, clear and transparent lignocellulose solution could not be obtained.

[0057] Example 9

[0058] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium chloride, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 160 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 8.0 g / 100 g.

[0059] Example 10

[0060] 2.0 g of a mixed solvent (1-ethyl-3-methylimidazolium chloride and ethanolamine in a 1:1 molar ratio) was added to a 10 mL glass bottle, along with 40 mg of ball-milled bagasse. The mixture was stirred continuously in a 90°C oil bath at 500 rpm for 5 hours to produce a homogeneous, stable, and transparent lignocellulose solution with a solubility of 2.0 g / 100 g. Experiments showed that a mixed solvent consisting of 1-ethyl-3-methylimidazolium chloride and ethanolamine could achieve complete dissolution, but the maximum solubility was only 2.0 g / 100 g. In comparison, the mixed solvent containing a third component (1,5-diazabicyclo[4.3.0]-5-nonene) in Example 9 achieved a maximum solubility of 8 g / 100 g, a fourfold increase.

[0061] Example 11

[0062] 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium chloride and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1) was added to a 10 mL glass bottle, 20 mg of ball-milled bagasse was added, and the mixture was placed in a 90 °C oil bath and stirred continuously for 5 hours at a speed of 500 r / min. However, a uniform, stable, clear and transparent lignocellulose solution could not be obtained.

[0063] Example 12

[0064] Take 2.0 g of mixed solvent (1-propyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 180 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 9.0 g / 100 g.

[0065] Example 13

[0066] Take 2.0 g of mixed solvent (1-propyl-3-methylimidazolium chloride, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 146 mg of ball-milled sugarcane bagasse and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 7.3 g / 100 g.

[0067] Example 14

[0068] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 292 mg of ball-milled sorghum straw and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 14.6 g / 100 g.

[0069] Example 15

[0070] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 184 mg of ball-milled bamboo and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 9.2 g / 100 g.

[0071] Example 16

[0072] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 206 mg of ball-milled corn cobs and place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 10.3 g / 100 g.

[0073] Example 17

[0074] Take 2.0 g of mixed solvent (1-ethyl-3-methylimidazolium acetate, ethanolamine and 1,5-diazabicyclo[4.3.0]-5-nonene in a molar ratio of 1:1:1) and add it to a 10 mL glass bottle. Add 400 mg of ball-milled Miscanthus sinensis, place it in a 90 ° C oil bath and stir continuously for 5 hours at a speed of 500 r / min to obtain a uniform, stable, clear and transparent lignocellulose solution with a solubility of 20.0 g / 100 g.

[0075] In summary, the mixed solvent system of the present invention is simple to prepare, has a strong ability to dissolve all components of lignocellulose, and the prepared lignocellulose solution has the characteristics of high lignocellulose concentration, uniformity, stability, clarity and transparency; it has low temperature requirements and does not require excessively high temperature and pressure, and can achieve efficient dissolution of all components of lignocellulose at 70-90°C; it has low requirements for the type of lignocellulose raw materials and can efficiently dissolve all components of typical lignocellulose raw materials such as grasses, broad-leaved wood and coniferous wood.

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A fast and efficient mixed solvent for dissolving all components of lignocellulose, wherein the mixed solvent system is composed of an ionic liquid, ethanolamine and an organic superbase; in, The ionic liquid is selected from one of 1-ethyl-3-methylimidazolium acetate, 1-propyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium chloride, 1-propyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, and 1-allyl-3-methylimidazolium chloride; The organic superbase is selected from one of 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]undec-7-ene and 1,1,3,3-tetramethylguanidine; The molar ratio of the ionic liquid, ethanolamine and organic superbase is 10-0.18:1:

1.

2. The mixed solvent according to claim 1, characterized in that The molar ratio of the ionic liquid, ethanolamine and organic superbase is 5-0.2:1:

1.

3. The mixed solvent according to claim 1, characterized in that The molar ratio of the ionic liquid, ethanolamine and organic superbase is 5:1:1, 4:1:1, 3:1:1, 2:1:1, 1:1:1, 1 / 2:1:1, 1 / 3:1:1, 1 / 4:1:1 or 1 / 5:1:

1.

4. A method for dissolving all components of lignocellulose, comprising: (1) mechanically refining and pulverizing the dried lignocellulose raw material in a planetary ball mill to form lignocellulose raw material particles; (2) dispersing the lignocellulose powder obtained in step (1) in the mixed solvent according to any one of claims 1 to 3, stirring continuously at 70-90° C. for 0.5 to 10 hours at a stirring speed of 200 to 1000 r / min, until the lignocellulose powder is completely dissolved to obtain a uniform, stable, clear and transparent lignocellulose solution.

5. The method for dissolving all components of lignocellulose according to claim 4, characterized in that: The lignocellulose raw material is selected from one of bagasse, sorghum straw, wheat straw, rice straw, corn cob, bamboo, Miscanthus, white poplar wood powder and radiata pine wood powder.

6. The method for dissolving all components of lignocellulose according to claim 5, characterized in that: The lignocellulose raw material is selected from one of sugarcane bagasse, sorghum straw, wheat straw, rice straw, corn cob, bamboo and miscanthus.

7. The method for dissolving all components of lignocellulose according to claim 4, characterized in that: The ball milling treatment in step (1) is carried out as follows: 10.0 g of cellulose powder passed through a 60-80 mesh sieve and 70 zirconium dioxide balls with a diameter of 10 mm are weighed and added to the zirconium dioxide tank of a planetary ball mill, and ball milled at a speed of 400 r / min for 4 hours, with a ball milling interval of 5 minutes and a rest time of 5 minutes after each ball milling.

8. The method for dissolving all components of lignocellulose according to claim 4, characterized in that: The dissolving stirring speed in step (2) is 400 to 800 r / min.

9. The method for dissolving all components of lignocellulose according to claim 4, characterized in that: The dissolving stirring speed in step (2) is 500 r / min.

10. The method for dissolving all components of lignocellulose according to claim 4, characterized in that: The stirring time in step (2) is 1-5 hours.

11. Use of a high-concentration lignocellulose solution containing all components prepared by the mixed solvent according to any one of claims 1 to 3 in the preparation of membrane materials, spinning materials and gel materials.

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