Method for producing a cellulose solution and use of a cellulose solution

Abstract

The application discloses a cellulose solution preparation method and application of the cellulose solution, and dissolves cellulose by taking organic alkali, COS and organic solvent as a dissolving system. The cellulose dissolving method has the characteristics of simple process, low cost, easy post-treatment, good dissolving stability, low viscosity of the dissolving system and convenient subsequent application. In addition, the cellulose solution of the application can obtain sulfur-containing cellulose derivative functional materials without thiol reaction in the subsequent derivative application process, and can be applied to the fields of wastewater treatment, biological medicine, electronic industry and coating industry, and the method has very important significance for promoting the derivative application of cellulose.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for dissolving cellulose for application, in particular a method for dissolving cellulose by using an organic base-COS-organic solvent dissolving system and the application of cellulose solution. BACKGROUND

[0002] As one of the important materials to promote the development of human civilization, high molecular materials have played a very important role in the process of human modern civilization development. However, most of the traditional high molecular materials are obtained from petroleum, and the large-scale use of them not only brings great consumption of non-renewable resources, but also causes great pressure on the environment. The research on the preparation of sustainable high molecular new materials from plants has attracted much attention.

[0003] Cellulose is the main component of plant cell wall and is a biorenewable resource that can be taken indefinitely and used indefinitely. Due to its renewable, cheap, biodegradable, easy surface modification, good mechanical properties and low density, it is of great significance to use the natural polymer skeleton of cellulose to construct green high molecular new materials to promote the sustainable development of human society.

[0004] In the application of cellulose in the construction of green high molecular new materials, it is necessary to dissolve cellulose to obtain cellulose solution. However, due to the existence of a large number of intermolecular and intramolecular hydrogen bonds in the structure of cellulose, it cannot be melt processed or dissolved in water and traditional organic solvents. Therefore, the research and development of cellulose dissolving system has attracted much attention from researchers.

[0005] In the traditional method of dissolving cellulose, the main methods include viscose method, cuprammonium method, cadmium / ethylenediamine solution, lithium chloride / dimethylacetamide method, 4-methylmorpholine-N-oxide (NMMO), NaOH / CS2 and carbamate solvent method. In addition, recent research results show that cellulose also has good dissolving effect in new ionic liquid, sodium hydroxide / urea aqueous solution and CO2-based reversible solvent system.

[0006] However, these traditional cellulose dissolution methods still have some problems in practical application, for example: the preparation cost of ionic liquid is relatively high, the production cost is increased in the preparation process, in addition, the recovery of ionic liquid needs complex process and equipment; the dissolution of cellulose in alkali / urea aqueous solution system generally needs to be carried out at low temperature, so the dissolution conditions are relatively harsh, in addition, the stability of the dissolution system is affected by external factors such as temperature and stirring, and the stability of the dissolution system is poor; although the CO2-based reversible solvent system has low cost and relatively simple post-processing, the stability of the dissolution system is also high, but the viscosity of the dissolution system is relatively large, and the dispersibility in the reaction system is poor in subsequent application, and the reaction speed is slow; in addition, the cellulose dissolved in the CO2-based reversible solvent system has limited functions, which cannot meet the needs of multifunctional derivatization of cellulose, for example, when preparing sulfur-containing cellulose derivatives, the cellulose needs to be dissolved first, and then a thiol reaction is carried out to obtain sulfur-containing cellulose.

[0007] Therefore, it is of great significance to further expand the application of cellulose in the field of new polymer materials by researching and developing different cellulose dissolution methods to reduce the dissolution cost, simplify the dissolution process, improve the dissolution stability, facilitate subsequent application and expand the functionality. SUMMARY

[0008] In order to solve the above technical problems, the present application provides a preparation method of cellulose solution and application of cellulose solution. The cellulose dissolution method of the present application has the characteristics of simple process, low cost, easy post-processing, good dissolution stability, low viscosity of dissolution system and convenient subsequent application; in addition, the cellulose solution of the present application can obtain sulfur-containing cellulose derivative functional materials without thiol reaction in the subsequent derivatization application process, and can be used in the fields of wastewater treatment, biological medicine, electronic industry and coating industry, which has great significance for promoting the derivatization application of cellulose.

[0009] One of the technical solutions of the present application is:

[0010] The present application provides a preparation method of cellulose solution, which uses a mixture of organic base, COS and organic solvent as the dissolution system to dissolve cellulose.

[0011] Preferably, the preparation method of cellulose solution comprises the following steps:

[0012] (1) mixing cellulose, organic base and organic solvent to obtain a mixture;

[0013] (2) placing the mixture in a reaction kettle, charging COS gas and sealing;

[0014] (3) heating the sealed reactor to make the mixture therein react, and obtaining a cellulose solution after the reaction.

[0015] Preferably, the method for preparing the cellulose solution, the cellulose is one or a combination of any of microcrystalline cellulose, cotton, wood pulp, bamboo pulp or straw cellulose.

[0016] Preferably, the method for preparing the cellulose solution, the cellulose has the following general chemical structure:

[0017]

[0018] wherein 50 < n-4 < 1000.

[0019] Preferably, the method for preparing the cellulose solution, the organic base is any of the following structures:

[0020]

[0021] wherein R is independently H, methyl or ethyl; R1 is independently H or -CH3; R2, R3, R4 and R5 are independently H or an alkyl group with 1-6 carbon atoms.

[0022] Preferably, the method for preparing the cellulose solution, the organic solvent is one or a mixture of any of dimethyl sulfoxide, N-methyl pyrrolidone, N,N-dimethyl imidazolidinone, N,N-dimethyl formamide, N,N-dimethyl acetamide, N,N-diethyl acetamide or N,N-dimethyl acryl ure.

[0023] Preferably, the method for preparing the cellulose solution, in the mixture of step (1), the mass concentration of cellulose is 1-20%, the mass concentration of organic base is 0.5-30%, and the rest is organic solvent.

[0024] Preferably, the method for preparing the cellulose solution, in the sealed reactor of step (2), the pressure of COS gas is 0.2-5 MPa.

[0025] Preferably, the method for preparing the cellulose solution, the final temperature of heating in step (3) is 30-70℃, and the reaction time is 2-6h.

[0026] Technical solution two of the present application:

[0027] A cellulose solution is provided, which is prepared according to the above method.

[0028] Technical solution three of the present application:

[0029] Provided is a sulfur-containing cellulose functional material prepared using the aforementioned cellulose solution and an acrylate compound as raw materials, wherein the acrylate compound is any one of the following compounds:

[0030]

[0031] wherein R is independently -CH3 or an alkyl group having 1-6 carbon atoms.

[0032] Preferably, the aforementioned sulfur-containing cellulose functional material is prepared by adding the acrylate compound to the cellulose solution, reacting at 25-35°C for 1-3 hours, then adding the reaction product to anhydrous ethanol, stirring to obtain a precipitate, and finally filtering the precipitate, washing with ethanol, and then drying to obtain a heavy metal ion adsorbent in solution.

[0033] Preferably, in the aforementioned sulfur-containing cellulose functional material, when the acrylate compound is added to the cellulose solution, the molar ratio of glucose units in the cellulose solution to C=C bonds in the acrylate compound is 1:1-3.

[0034] Fourth aspect of the technical solution of the present application:

[0035] Provided is the use of the aforementioned sulfur-containing cellulose functional material in the fields of wastewater treatment, biological medicine, electronics industry, and coating industry.

[0036] Advantages of the present application:

[0037] 1. The cellulose dissolution method of the present application uses a dissolution system composed of an organic base, COS, and an organic solvent, which is a completely new dissolution system different from existing cellulose dissolution systems.

[0038] 2. The cellulose dissolution method of the present application uses a dissolution system that is low in cost, simple in process, and easy to handle, which has natural advantages in promoting the industrial application of the dissolution system.

[0039] 3. The cellulose dissolution method of the present application uses a dissolution system that, when actually applied, results in a more stable cellulose solution, which is more convenient for industrial application.

[0040] 4. The cellulose solution obtained by the dissolution method of the present application has lower viscosity, which is beneficial to accelerating the diffusion speed of raw materials and shortening the reaction time in subsequent multi-component reactions.

[0041] 5. The sulfur-containing cellulose functional material prepared by the serial reaction of the cellulose solution obtained by the dissolution method of the present application and an acrylate compound can be used in the fields of wastewater treatment, biological medicine, electronics industry, and coating industry, which is of great significance in promoting the application of cellulose derivatives. Attached Figure Description

[0042] Figure 1 The image shows a polarized light microscope image of microcrystalline cellulose dissolved by reacting COS at 30°C for 4 hours under a pressure of 1.0 MPa. The polarized light microscope image shows that the microcrystalline cellulose (MCC) is completely dissolved, which fully demonstrates that the new DBU / COS / DMSO dissolution system has good dissolving ability for cellulose under these conditions.

[0043] Figure 2 The image shows a comparison of XRD patterns between dissolved microcrystalline cellulose (MCC) and pure cellulose after reacting with COS at 1.0 MPa at 30°C for 4 hours. In the image of undissolved microcrystalline cellulose (MCC), distinct characteristic diffraction peaks are observed at 2θ = 15.3°, 22.4°, and 34.3°, indicating that the original MCC crystal structure belongs to cellulose type I. Conversely, the regenerated cellulose (R-MCC) obtained by dissolving and reprecipitating MCC using the dissolution system of this invention under the same conditions only shows a broad single characteristic diffraction peak at 2θ = 19.64°, indicating that the dissolved and regenerated MCC has an amorphous structure, and that the crystal structure of the MCC has completely changed after dissolution.

[0044] Figure 3 This is a real-time infrared spectrum of cellulose dissolution; from the real-time infrared spectrum, it can be seen that as the reaction time increases, NH... + (2350~2650cm -1 C=O(1550~1700cm) -1 COR (1160~1260cm) -1 ) and NH (840~760cm -1 The characteristic peak intensity of the reaction was significantly enhanced, and the peak intensity did not change when the reaction time was extended to 4 hours, indicating that cellulose could be completely dissolved after being pressed at 1.0 MPa and reacted at 30℃ for 4 hours.

[0045] Figure 4 A comparative rheological test diagram showing the dissolution of 5 wt% cellulose in the DBU / CO2 / DMSO system and the organic base-COS-organic solvent system of this invention. The diagram clearly shows that the cellulose solution dissolved using the system of this invention exhibits dilute solution behavior, typical of Newtonian fluids; while the cellulose solution dissolved using the DBU / CO2 / DMSO system shows an increase in apparent viscosity, exhibiting shear thinning in the low shear rate region, and an increase in cellulose solution concentration, indicating stronger intermolecular forces. Detailed Implementation

[0046] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0047] Embodiments of the present invention

[0048] The "COS" described in the present invention is carbonyl sulfide.

[0049] Example 1

[0050] 1 g of microcrystalline cellulose, 2.828 g of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and 15.367 g of dimethyl sulfoxide (DMSO) were weighed into the reaction kettle, and the reaction kettle was covered.

[0051] The reaction kettle was then charged with COS gas at 0.2 MPa, and the reaction kettle was heated to 30°C, and stirred for 2 h to obtain a homogeneous cellulose solution.

[0052] Example 2

[0053] The mixture system in the reaction kettle of this example was the same as that of Example 1.

[0054] The difference was that the reaction kettle was charged with COS gas at 0.5 MPa, and the reaction kettle was heated to 30°C, and stirred for 2 h to obtain a homogeneous cellulose solution.

[0055] Example 3

[0056] The mixture system in the reaction kettle of this example was the same as that of Example 1.

[0057] The difference was that the reaction kettle was charged with COS gas at 1.0 MPa, and the reaction kettle was heated to 30°C, and stirred for 2 h to obtain a homogeneous cellulose solution.

[0058] Example 4

[0059] The mixture system in the reaction kettle of this example was the same as that of Example 1.

[0060] The difference was that the reaction kettle was charged with COS gas at 3.0 MPa, and the reaction kettle was heated to 30°C, and stirred for 2 h to obtain a homogeneous cellulose solution.

[0061] Example 5

[0062] The mixture system in the reaction kettle of this example was the same as that of Example 1.

[0063] The difference was that the reaction kettle was charged with COS gas at 5.0 MPa, and the reaction kettle was heated to 30°C, and stirred for 2 h to obtain a homogeneous cellulose solution.

[0064] Example 6

[0065] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0066] The difference is that in this example, COS gas is filled into the reaction kettle at 0.2 MPa, and then the reaction kettle is heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0067] Example 7:

[0068] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0069] The difference is that in this example, COS gas is filled into the reaction kettle at 0.5 MPa, and then the reaction kettle is heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0070] Example 8:

[0071] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0072] The difference is that in this example, COS gas is filled into the reaction kettle at 1.0 MPa, and then the reaction kettle is heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0073] Example 9:

[0074] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0075] The difference is that in this example, COS gas is filled into the reaction kettle at 3.0 MPa, and then the reaction kettle is heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0076] Example 10:

[0077] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0078] The difference is that in this example, COS gas is filled into the reaction kettle at 5.0 MPa, and then the reaction kettle is heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0079] Example 11:

[0080] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0081] The difference is that in this example, COS gas is filled into the reaction kettle at 1.0 MPa, and then the reaction kettle is heated to 50°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0082] Example 12:

[0083] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0084] The difference is that COS gas is filled into the reaction kettle at 3.0 MPa in this example, and then the reaction kettle is heated to 50°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0085] Example 13:

[0086] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0087] The difference is that COS gas is filled into the reaction kettle at 1.0 MPa in this example, and then the reaction kettle is heated to 70°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0088] Example 14:

[0089] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0090] The difference is that COS gas is filled into the reaction kettle at 3.0 MPa in this example, and then the reaction kettle is heated to 70°C, and stirred for 4 h to obtain a homogeneous cellulose solution.

[0091] Example 15:

[0092] The mixture system in the reaction kettle of this example is the same as that of Example 1.

[0093] The difference is that COS gas is filled into the reaction kettle at 1.0 MPa in this example, and then the reaction kettle is heated to 30°C, and stirred for 6 h to obtain a homogeneous cellulose solution.

[0094] The COS in the reaction kettle after the reaction of Examples 1-15 is released, and then the micro-morphology of the cellulose solution therein is observed by using a polarizer, and the relevant results are shown in Table 1 below:

[0095] Table 1

[0096]

[0097]

[0098] Note: "-" means not completely dissolved, and "+" means completely dissolved

[0099] The results fully show that when the reaction pressure is >0.5 MPa, the time is >4 h, and the temperature is <50°C, the cellulose can be completely dissolved.

[0100] Example 16:

[0101] Take 5wt% of microcrystalline cellulose, 10wt% of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and the rest of dimethyl sulfoxide (DMSO), mix them and then add them into the reaction kettle, cover the reaction kettle;

[0102] Charge 1.0MPa of COS gas into the reaction kettle, stir the reaction at 30℃ for 4h to obtain a homogeneous cellulose solution.

[0103] Example 17:

[0104] The reaction conditions of this example are consistent with those of Example 12;

[0105] The difference is that 15wt% of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) is taken in this example.

[0106] Example 18:

[0107] The reaction conditions of this example are consistent with those of Example 12;

[0108] The difference is that 20wt% of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) is taken in this example.

[0109] Example 19:

[0110] The reaction conditions of this example are consistent with those of Example 12;

[0111] The difference is that 10wt% of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is taken in this example.

[0112] Example 20:

[0113] The reaction conditions of this example are consistent with those of Example 12;

[0114] The difference is that 10wt% of triethylamine (TEA) is taken in this example.

[0115] Release the COS gas in the reaction kettles of Examples 16-20, and then use polarized light to observe the micro-morphology of the cellulose solution, and the relevant results are shown in Table 2:

[0116] Table 2

[0117] No. Cellulose content wt% Organic base and content wt% Organic solvent Polarization 16 5 10 wt% DBU DMSO + 17 5 15 wt% DBU DMSO + 18 5 20 wt% DBU DMSO + 19 5 10 wt% DBN DMSO - 20 5 10 wt% TEA DMSO -

[0118] Note: "-" means not completely dissolved, "+" means completely dissolved

[0119] The results fully demonstrate that the DBU, which is stronger in alkalinity, has good dissolving effect on cellulose when used as the solvent (mass fraction ≥ 10 wt%). In addition, when the same mass fraction of organic base is added, the dissolving effect of DBU is better than that of DBN and TEA.

[0120] Example 21

[0121] 1 g of microcrystalline cellulose was weighed, 2.828 g of organic base 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) was taken, then 15.367 g of organic solvent dimethyl sulfoxide (DMSO) was weighed, and the mixture was added to the reaction kettle, and the reaction kettle was covered.

[0122] 1.0 MPa of COS gas was filled into the reaction kettle, and the reaction was stirred at 30°C for 4 h to obtain a homogeneous cellulose solution.

[0123] Example 22

[0124] The reaction conditions of this example are consistent with those of Example 17;

[0125] The difference is that the organic solvent added in this example is N,N-dimethylformamide (DMF).

[0126] Example 23

[0127] The reaction conditions of this example are consistent with those of Example 17;

[0128] The difference is that the organic solvent added in this example is N,N-dimethylacetamide (DMAc).

[0129] Example 24

[0130] The reaction conditions of this example are consistent with those of Example 17;

[0131] The difference is that the organic solvent added in this example is N-methyl pyrrolidone (NMP).

[0132] The COS gas in the reaction kettle of Examples 21-24 was released, and the microstructure of the cellulose solution was observed by polarized light. The relevant results are shown in Table 3:

[0133] Table 3

[0134] No. Cellulose content wt% Organic base Organic solvent Polarization 21 5 DBU DMSO + 22 5 DBU DMF - 23 5 DBU DMAc - 24 5 DBU NMP -

[0135] Note: "-" means not completely dissolved, "+" means completely dissolved

[0136] The results fully demonstrate that when DMSO, which is larger in polarity, is used as the solvent, the dissolving effect of the DBU / COS / DMSO system on cellulose is obviously better than that of the other three.

[0137] Example 25

[0138] The microcrystalline cellulose 7wt%, 2.828g of organic base 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and the rest of the organic solvent dimethyl sulfoxide (DMSO) were weighed and mixed, and then added to the inside of the reaction kettle, and the reaction kettle was covered.

[0139] The reaction kettle was filled with 1.0 MPa of COS gas, and stirred at 30°C for 4h to obtain a homogeneous cellulose solution.

[0140] Example 26

[0141] The reaction conditions of this example are consistent with Example 21.

[0142] The difference is that the mass concentration of cellulose in this example is 10wt%.

[0143] Example 27

[0144] The reaction conditions of this example are consistent with Example 21.

[0145] The difference is that the mass concentration of cellulose in this example is 12wt%.

[0146] Example 28

[0147] The reaction conditions of this example are consistent with Example 21.

[0148] The difference is that the mass concentration of cellulose in this example is 15wt%.

[0149] The COS gas in the reaction kettle of Examples 25-28 was released, and the microstructure of the cellulose solution was observed using polarized light, and the relevant results are shown in Table 4 below:

[0150] Table 4

[0151] No. Cellulose content wt% Organic base Organic solvent Polarization 25 7 DBU DMSO + 26 10 DBU DMSO - 27 12 DBU DMSO - 28 15 DBU DMSO -

[0152] Note: "-" means not completely dissolved, "+" means completely dissolved

[0153] The results fully demonstrate that when using the polar DMSO and the strong basic DBU as the solvent, the cellulose has good dissolution effect, and the maximum dissolution concentration reaches 7wt%.

[0154] Example 29

[0155] Take 5wt% of microcrystalline cellulose, 15wt% of organic base 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and the rest of the organic solvent dimethyl sulfoxide (DMSO), then mix them and add them into the reaction kettle, cover the reaction kettle;

[0156] Fill the reaction kettle with 1.0 MPa of COS gas, stir at 30°C for 4h to obtain a homogeneous cellulose solution.

[0157] Example 30:

[0158] The reaction conditions of this example are consistent with Example 25;

[0159] The difference is that the cellulose of this example is cotton pulp cellulose.

[0160] Example 31:

[0161] The reaction conditions of this example are consistent with Example 25;

[0162] The difference is that the cellulose of this example is bamboo pulp cellulose.

[0163] Example 32:

[0164] The reaction conditions of this example are consistent with Example 25;

[0165] The difference is that the cellulose of this example is corn straw.

[0166] Release the COS gas in the reaction kettle of Examples 29-32, then use polarized light to observe the micro-morphology of the cellulose solution, and the relevant results are shown in Table 5:

[0167] Table 5

[0168] No. Cellulose content wt% Organic base Organic solvent Cellulose Polarization 29 5 DBU DMSO Microcrystalline cellulose + 30 5 DBU DMSO Cotton pulp cellulose - 31 5 DBU DMSO Bamboo pulp cellulose - 32 5 DBU DMSO Corn straw -

[0169] Note: "-" means not completely dissolved, "+" means completely dissolved

[0170] This conclusion fully demonstrates that the solubility of cellulose in the DBU / COS / DMSO new solvent system is significantly reduced after the degree of polymerization of cellulose is increased.

[0171] Example 33

[0172] Take 1g of microcrystalline cellulose, 2.828g of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 15.367g of dimethyl sulfoxide (DMSO) into the reaction kettle, cover the reaction kettle;

[0173] The reaction kettle was filled with COS gas at 1.0 MPa, and then the reaction kettle was heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution;

[0174] The methacrylate was added by an in-situ feeding device, the molar ratio of C=C bond in the methacrylate to glucose unit in the cellulose solution was controlled to be 3:1, and a red-brown homogeneous solution was obtained by reacting at 30°C for 2 h. The reaction solution was added dropwise into anhydrous ethanol at a speed of 1-2 drops / s, and was added while stirring. The precipitate was filtered and washed with 200 mL of ethanol for 2-3 times, and was dried in a vacuum oven at 60°C for 48 h to obtain a sulfur-containing cellulose functional material.

[0175] Example 34

[0176] The reaction conditions of this example were consistent with those of Example 33.

[0177] The difference is that the acrylate compound of this example is phenethyl acrylate.

[0178] Example 35

[0179] The reaction conditions of this example were consistent with those of Example 33.

[0180] The difference is that the acrylate compound of this example is 4-formyl-2-methoxyphenyl acrylate.

[0181] The products of the coupling reaction of the different acrylate compounds in Examples 33-35 were detected, and the related results are shown in Table 5 below:

[0182] Table 6

[0183] No. Acrylate compound Degree of substitution Yield 33 Methacrylate 1.15 86 34 Phenylethyl acrylate 0.84 80 35 4-Formyl-2-methoxyphenyl acrylate 0.68 71

[0184] This example fully demonstrates that different acrylate compounds can be coupled with the cellulose solution of the present application.

[0185] Example 36

[0186] 1 g of microcrystalline cellulose, 2.828 g of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and 15.367 g of dimethyl sulfoxide (DMSO) were added to the reaction kettle, and the reaction kettle was covered;

[0187] The reaction kettle was filled with COS gas at 1.0 MPa, and then the reaction kettle was heated to 30°C, and stirred for 4 h to obtain a homogeneous cellulose solution;

[0188] The in-situ feeding device was used to add methacrylate, and the molar ratio of C=C bond in methacrylate to glucose unit in cellulose solution was controlled to be 2:1, and a red-brown homogeneous solution was obtained after reaction at 25°C for 3h. The reaction solution was added dropwise into anhydrous ethanol at a rate of 1-2 drops / s, and the precipitate was filtered and washed with 200mL of ethanol for 2-3 times, and then dried in a vacuum oven at 60°C for 48h to obtain sulfur-containing cellulose functional material.

[0189] Example 37

[0190] 1g of microcrystalline cellulose, 2.828g of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 15.367g of dimethyl sulfoxide (DMSO) were weighed into the reaction kettle, and the reaction kettle was covered;

[0191] COS gas was filled into the reaction kettle at 1.0MPa, and then the reaction kettle was heated to 30°C, and stirred for 4h to obtain a homogeneous cellulose solution;

[0192] The in-situ feeding device was used to add methacrylate, and the molar ratio of C=C bond in methacrylate to glucose unit in cellulose solution was controlled to be 1:1, and a red-brown homogeneous solution was obtained after reaction at 35°C for 1h. The reaction solution was added dropwise into anhydrous ethanol at a rate of 1-2 drops / s, and the precipitate was filtered and washed with 200mL of ethanol for 2-3 times, and then dried in a vacuum oven at 60°C for 48h to obtain sulfur-containing cellulose functional material.

[0193] Example 38

[0194] 10mg of sulfur-containing functional cellulose in Example 33 was weighed into 5 40mL glass bottles respectively, and then 20mL of 500ppm copper chloride, mercury chloride, chromium chloride, zinc chloride and cadmium chloride solution was added respectively, and the removal rate was analyzed by ACP tester after shaking at room temperature for 24h. The corresponding test results are shown in the following table:

[0195] Table 7

[0196] No. Heavy metal solution Adsorption time (h) Removal rate %) 36 Mercury chloride 24 99.6 37 Copper chloride 24 25.2 38 Zinc chloride 24 11.7 39 Chromium chloride 24 22.9 40 Cadmium chloride 24 23.3

[0197] This example illustrates that the product after acrylate-COS-cellulose multi-component coupling reaction has good adsorption effect on heavy metals, and has better removal effect on mercury ions in particular.

[0198] The above merely describes preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical scope disclosed by the present application, and all of them shall be covered within the protection scope of the present application.

Claims

1. A method for preparing a cellulose solution, characterized in that, The method includes the following steps: (1) Mix cellulose, organic base and organic solvent to obtain a mixture; (2) Place the mixture in a reactor, fill it with COS gas, and then seal it. (3) The sealed reaction vessel is heated to cause the mixture inside to react, and a cellulose solution is obtained after the reaction is completed; In the sealed reactor described in step (2), the pressure of COS gas is 0.2-5 MPa.

2. The method for preparing cellulose solution according to claim 1, characterized in that: The cellulose is one or a combination of microcrystalline cellulose, cotton, wood pulp, bamboo pulp or straw cellulose; The cellulose has the following general chemical structural formula: ； Where 50 < n-4 < 1000; The organic base is any one of the following structures: ； Wherein: R is an independent H, methyl or ethyl; R1 is an independent H or -CH3; R2, R3, R4 and R5 are independent H or alkyl groups having 1-6 C atoms; The organic solvent is one or a mixture of any of the following: dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylimidazolinone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, or N,N-dimethylpropenylurea.

3. The method for preparing cellulose solution according to claim 1, characterized in that: In the mixture described in step (1), the mass concentration of cellulose is 1-20%, the mass concentration of organic base is 0.5-30%, and the remainder is organic solvent.

4. The method for preparing cellulose solution according to claim 1, characterized in that: The final heating temperature in step (3) is 30-70℃, and the reaction time is 2-6h.

5. A sulfur-containing cellulose functional material, characterized in that: It is prepared using a cellulose solution obtained by the method according to any one of claims 1-4 and an acrylate compound as raw materials, wherein the acrylate compound is any one of the following compounds: ； Wherein: R is an independent -CH3 or an alkyl group having 1-6 C atoms.

6. The sulfur-containing cellulose functional material according to claim 5, characterized in that: The preparation method involves adding an acrylate compound to the cellulose solution, reacting at 25-35°C for 1-3 hours, then adding the reaction product to anhydrous ethanol, stirring to obtain a precipitate, filtering out the precipitate, washing it with ethanol, and then drying it to obtain a heavy metal ion adsorbent in the solution.

7. The sulfur-containing cellulose functional material according to claim 6, characterized in that: When acrylate compounds are added to the cellulose solution, the molar ratio of glucose units in the cellulose solution to C=C bonds in the acrylate compounds is 1:1-3.

8. The application of a sulfur-containing cellulose functional material according to any one of claims 5-7 in the fields of wastewater treatment, biomedicine, electronics industry and coatings industry.

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