A method for hydrolyzing cellulose material

Abstract

The present invention relates to the technical field of cellulosic material hydrolysis, and in particular to a cellulosic material hydrolysis method, comprising the following steps: S1, ball milling pretreatment of the cellulosic material; S2, preparing a deep eutectic solvent; S3, dissolving the cellulosic material using the deep eutectic solvent; S4, preparing a sulfonated carbon catalyst; S5, hydrolyzing the cellulosic material using the sulfonated carbon catalyst. Compared with the prior art, the present invention has greatly improved reaction conditions (>60wt% sulfuric acid), reaction time (>24 hours), conversion rate (about 84%) and glucose yield (about 50%), and has simple method, high efficiency, low cost and good practicality.

Description

Technical Field

[0001] The invention relates to the technical field of cellulose material hydrolysis, and in particular to a cellulose material hydrolysis method. Background Art

[0002] Cellulosic materials are derived from plant fibers (such as cotton, corn stalks, etc.), and have the advantages of abundant material sources, renewability, and carbon neutrality. Therefore, biofuels and biochemical products prepared from cellulosic materials are expected to become a solution to achieve a carbon-neutral economy. However, although various complex thermochemical processes have been developed to prepare cellulosic materials into biofuels and biochemical products, most existing technologies are costly and less competitive than fossil fuels. The main cost limiting factor is that the process of hydrolyzing cellulosic materials into processable monomer units (such as glucose) is very slow. The hydrolysis of cellulosic materials into glucose monomers in the prior art usually involves very long reaction times (>24 hours) and harsh reaction conditions (>60wt% sulfuric acid). In order to solve this problem, ball milling pretreatment is traditionally applied before hydrolysis of cellulosic materials, and the crystallinity of cellulosic materials is deconstructed by mechanical crushing, such as the Chinese invention patent with application number CN201810364785.9 and the name of a method for preparing bio-oil by pyrolysis of microcrystalline cellulose pretreated with ball milling. However, the high energy consumption of the ball milling process is still a problem that limits the cost of cellulosic materials. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a cost-saving method for hydrolyzing cellulose materials.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for hydrolyzing cellulose materials, comprising the following steps:

[0005] S1. Pre-treating the cellulose material by ball milling;

[0006] S2, preparing a deep co-solvent;

[0007] S3, dissolving the cellulose material using a deep co-solvent;

[0008] S4, preparing a sulfonated carbon catalyst;

[0009] S5. Using a sulfonated carbon catalyst to hydrolyze the cellulose material.

[0010] Furthermore, the S1 specifically includes:

[0011] The cellulose material is ball-milled using zirconium oxide balls with a weight ratio of 1:0.02-0.04 to the cellulose material.

[0012] Furthermore, the S2 specifically includes:

[0013] Lactic acid and choline chloride are mixed in a molar ratio of 8 to 10:1, and stirred at a temperature of 70 to 75° C. to form a transparent liquid, and the transparent liquid is cooled to room temperature to obtain a deep eutectic solvent.

[0014] Furthermore, the step S3 specifically includes step S31:

[0015] The cellulose material and the deep co-solvent are mixed at a mass ratio of 0.04 to 0.06:1 to obtain a mixture.

[0016] Furthermore, the step S3 specifically includes step S32:

[0017] The mixture was stirred at a temperature of 90 to 100°C.

[0018] Furthermore, the step S3 specifically includes step S33:

[0019] The stirred mixture is cooled to room temperature, deionized water is added and stirred again, and then centrifuged to remove the supernatant of the centrifuged solution to obtain a cellulose material gel.

[0020] Furthermore, the step S4 specifically includes step S41:

[0021] Activated carbon and 65% nitric acid are mixed at a ratio of 0.1 to 0.15 g / mL to obtain a mixture, and the mixture is heated to 55 to 60° C., the activated carbon in the mixture is separated and washed to be neutral, and the activated carbon is dried to obtain activated carbon powder.

[0022] Furthermore, the step S4 specifically includes step S42:

[0023] Activated carbon powder and 98% concentrated sulfuric acid are mixed at a ratio of 0.06-0.08 g / mL to obtain a mixture, and the mixture is heated to 200-210° C., then cooled to room temperature, the activated carbon powder in the mixture is separated and washed, and finally a sulfonated carbon catalyst is obtained after drying and calcination.

[0024] Furthermore, the step S5 specifically includes step S51:

[0025] The cellulose material gel and the sulfonated carbon catalyst are mixed at a mass ratio of 3:1, and then mixed with deionized water at a ratio of 0.025-0.035 g / mL to obtain a mixture.

[0026] Furthermore, the step S5 specifically includes step S52:

[0027] The mixture is stirred in an environment of 3 to 5 MPa and a temperature of 140 to 160° C. to perform a cellulose hydrolysis reaction.

[0028] The beneficial effects of the present invention are as follows: a highly efficient and low-energy consumption method for hydrolyzing cellulose materials is proposed, wherein the method utilizes a deep co-solvent to dissolve the cellulose material and prepares a sulfonated carbon catalyst for hydrolyzing the cellulose material, thereby overcoming the problems of long reaction time, harsh reaction conditions, high energy consumption, low efficiency and high cost in the cellulose hydrolysis process in the prior art. Compared with the reaction conditions (>60wt% sulfuric acid), reaction time (>24 hours), conversion rate (about 84%) and glucose yield (about 50%) of the prior art, there are significant improvements, the hydrolysis reaction conditions are reduced to 150°C, the reaction time is reduced to 12 hours, the conversion rate of the cellulose material reaches about 97%, and the glucose yield reaches 68%. The method is simple, efficient, low-cost and has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a method for hydrolyzing cellulose materials according to an embodiment of the present invention; DETAILED DESCRIPTION

[0030] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0031] The present invention relates to a cellulose hydrolysis method, please refer to Figure 1 , a method for hydrolyzing cellulose material is proposed, comprising the following steps:

[0032] S1. Pre-treating the cellulose material by ball milling;

[0033] S2, preparing a deep co-solvent;

[0034] S3, dissolving the cellulose material using a deep co-solvent;

[0035] S4, preparing a sulfonated carbon catalyst;

[0036] S5. Using a sulfonated carbon catalyst to hydrolyze the cellulose material.

[0037] From the above description, it can be seen that the beneficial effects of the present invention are: proposing an efficient and low-energy method for hydrolyzing cellulose materials, which utilizes a deep co-solvent to dissolve the cellulose material and prepare a sulfonated carbon catalyst for hydrolyzing the cellulose material, overcoming the problems of long reaction time, harsh reaction conditions, high energy consumption, low efficiency and high cost in the cellulose hydrolysis process in the prior art. Compared with the reaction conditions (>60wt% sulfuric acid), reaction time (>24 hours), conversion rate (about 84%) and glucose yield (about 50%) of the prior art, there are significant improvements. The hydrolysis reaction conditions are reduced to 150°C, the reaction time is reduced to 12 hours, the conversion rate of the cellulose material reaches about 97%, and the glucose yield reaches 68%. The method is simple, efficient, low-cost and practical.

[0038] In an optional embodiment, the S1 specifically includes:

[0039] The cellulose material is ball-milled using zirconium oxide balls with a weight ratio of 1:0.02-0.04 to the cellulose material.

[0040] It can be seen from the above description that the cellulose material is placed in a ball mill for ball milling to destroy the hydrogen bonds of the cellulose material to deconstruct the crystallinity of the cellulose material.

[0041] In an optional embodiment, the S2 specifically includes:

[0042] Lactic acid and choline chloride are mixed in a molar ratio of 8 to 10:1, and stirred at a temperature of 70 to 75° C. to form a transparent liquid, and the transparent liquid is cooled to room temperature to obtain a deep eutectic solvent.

[0043] In an optional embodiment, the step S3 specifically includes step S31:

[0044] The cellulose material and the deep co-solvent are mixed at a mass ratio of 0.04 to 0.06:1 to obtain a mixture.

[0045] In an optional embodiment, the step S3 specifically includes step S32:

[0046] The mixture was stirred at a temperature of 90 to 100°C.

[0047] In an optional embodiment, the step S3 specifically includes step S33:

[0048] The stirred mixture is cooled to room temperature, deionized water is added and stirred again, and then centrifuged to remove the supernatant of the centrifuged solution to obtain a cellulose material gel.

[0049] In an optional embodiment, the S4 specifically includes step S41:

[0050] Activated carbon and 65% nitric acid are mixed at a ratio of 0.1 to 0.15 g / mL to obtain a mixture, and the mixture is heated to 55 to 60° C., the activated carbon in the mixture is separated and washed to be neutral, and the activated carbon is dried to obtain activated carbon powder.

[0051] In an optional embodiment, the step S4 specifically includes step S42:

[0052] Activated carbon powder and 98% concentrated sulfuric acid are mixed at a ratio of 0.06-0.08 g / mL to obtain a mixture, and the mixture is heated to 200-210° C., then cooled to room temperature, the activated carbon powder in the mixture is separated and washed, and finally a sulfonated carbon catalyst is obtained after drying and calcination.

[0053] In an optional embodiment, the step S5 specifically includes step S51:

[0054] The cellulose material gel and the sulfonated carbon catalyst are mixed at a mass ratio of 3:1, and then mixed with deionized water at a ratio of 0.025-0.035 g / mL to obtain a mixture.

[0055] In an optional embodiment, the step S5 specifically includes step S52:

[0056] The mixture is stirred in an environment of 3 to 5 MPa and a temperature of 140 to 160° C. to perform a cellulose hydrolysis reaction.

[0057] Please refer to Figure 1 , Embodiment 1 of the present invention is:

[0058] A highly efficient and low energy consumption method for hydrolyzing cellulose materials:

[0059] S1, ball milling pretreatment of cellulose materials;

[0060] S2, preparing a deep co-solvent;

[0061] S3, dissolving the cellulose material using a deep co-solvent;

[0062] S4, preparing a sulfonated carbon catalyst;

[0063] S5. Performing a hydrolysis reaction of the cellulose material.

[0064] The specific operation of step S1 is: placing the cellulose material into a ball mill for ball milling to break the hydrogen bonds of the cellulose material to deconstruct the crystallinity of the cellulose material;

[0065] Preferably, the ball milling equipment consists of a roller ball mill, a porcelain pot and zirconium oxide balls;

[0066] Preferably, the diameter of the zirconia ball can be selected as: 5mm or 10mm;

[0067] Preferably, the weight ratio of cellulose to zirconium oxide balls is 0.02-0.04;

[0068] Preferably, the speed of the roller ball mill is set to 60-80 rpm, and the ball milling time is 2-3 days;

[0069] The specific operation of step S2 is: putting lactic acid and choline chloride into a beaker at a molar ratio of 8 to 10:1; then, stirring at 70-75° C. until it becomes a transparent liquid; then, cooling the mixture to room temperature to prepare a deep eutectic solvent;

[0070] The specific operation of step S3 is: the cellulose material obtained in step S1 and the deep eutectic solvent obtained in step S2 are proportioned and mixed at a mass ratio of 0.04-0.06, the mixture is put into a stirrer, the temperature is set to 90-100°C, the stirring rate is 60-70 rpm, and the stirring is performed for 5-6 hours; after stirring, the mixture is taken out and cooled to room temperature; after cooling, an excess amount of deionized water is added to the mixture, the mixture is put into a stirrer, the temperature is set to room temperature, the stirring rate is 70-80 rpm, and the stirring is performed for 1-2 hours; after stirring, the mixture is taken out and put into a centrifuge, the centrifuge speed is set to 2500-3000 rpm, and the mixture is rotated for 10-15 minutes. After taking out, the supernatant in the centrifuged solution is removed to obtain a cellulose material gel;

[0071] The specific operation of step S4 is as follows: activated carbon and 65% nitric acid are mixed at a ratio of 0.1-0.15 g / mL, 65% nitric acid is slowly added to a beaker containing activated carbon, and the mixture is added at 55-60° C. for 40-50 minutes; then, the activated carbon is separated by filtration, and then the activated carbon is washed with excess distilled water until it becomes neutral; then, the activated carbon is placed in an oven, set to 110-120° C., and dried for 10-12 hours to obtain activated carbon powder; the obtained carbon powder and 98% Concentrated sulfuric acid is prepared at a ratio of 0.06-0.08 g / mL, and 98% concentrated sulfuric acid is slowly added to the activated carbon powder, and the mixture is heated to 200-210° C. in a nitrogen atmosphere and maintained for 18-20 hours; thereafter, the mixture is cooled to room temperature, the activated carbon powder is filtered out and washed with hot distilled water; finally, the powder is placed in an oven, the oven is set to 110-120° C., and dried for 10-12 hours; and then calcined at 200-220° C. in a nitrogen atmosphere for 2-3 hours to obtain a sulfonated carbon catalyst;

[0072] The specific operation of step S5 is: the cellulose material gel obtained in step S3 and the sulfonated carbon catalyst obtained in step S4 are mixed in a mass ratio of 3:1, the mixture is mixed with deionized water in a ratio of 0.025-0.035 g / mL, the mixture is placed in a high-pressure reactor, the pressure in the reactor is set to 3-5 MPa with nitrogen, the temperature is set to 150° C., the stirring rate is set to 300-350 rpm, the reaction time is 12 hours, and the cellulose hydrolysis reaction is performed;

[0073] In summary, the present invention proposes a method for hydrolyzing cellulose materials with high efficiency and low energy consumption. The method uses a deep co-solvent to dissolve the cellulose material and prepare a sulfonated carbon catalyst to hydrolyze the cellulose material, overcoming the problems of long reaction time, harsh reaction conditions, high energy consumption, low efficiency and high cost in the cellulose hydrolysis process in the prior art. Compared with the reaction conditions (>60wt% sulfuric acid), reaction time (>24 hours), conversion rate (about 84%) and glucose yield (about 50%) of the prior art, there are significant improvements. The hydrolysis reaction conditions are reduced to 150°C and the reaction time is reduced to 12 hours. The conversion rate of the cellulose material reaches about 97% and the glucose yield reaches 68%. The method is simple, efficient, low-cost and practical.

[0074] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for hydrolyzing a cellulose material, characterized in that: The following steps are involved: S1, ball milling the cellulose material using zirconium oxide balls at a weight ratio of 1:0.02-0.04 to the cellulose material; S2, mixing lactic acid and choline chloride in a molar ratio of 8 to 10:1, stirring at a temperature of 70 to 75° C. to form a transparent liquid, and cooling the transparent liquid to room temperature to obtain a deep eutectic solvent; S3, mixing the cellulose material and the deep co-solvent in a mass ratio of 0.04 to 0.06:1 to obtain a mixture; Stirring the mixture at a temperature of 90 to 100° C.; S4, mixing activated carbon and 65% nitric acid at a ratio of 0.1 to 0.15 g / mL to obtain a mixture, heating the mixture to 55 to 60° C., separating the activated carbon in the mixture and washing it to neutrality, and drying the activated carbon to obtain activated carbon powder; The activated carbon powder and 98% concentrated sulfuric acid are mixed at a ratio of 0.06-0.08 g / mL to obtain a mixture, and the mixture is heated to 200-210° C., then cooled to room temperature, the activated carbon powder in the mixture is separated and washed, and finally dried and calcined to obtain a sulfonated carbon catalyst; S5. After mixing the cellulose material gel and the sulfonated carbon catalyst in a mass ratio of 3:1, the mixture is mixed with deionized water in a ratio of 0.025-0.035 g / mL to obtain a mixture, and then a hydrolysis reaction is performed.

2. The method for hydrolyzing cellulose materials according to claim 1, characterized in that: The S3 specifically includes step S33: The stirred mixture is cooled to room temperature, deionized water is added and stirred again, and then centrifuged to remove the supernatant of the centrifuged solution to obtain a cellulose material gel.

3. The method for hydrolyzing cellulose materials according to claim 1, characterized in that: The S5 specifically includes step S52: The mixture is stirred in an environment of 3 to 5 MPa and a temperature of 140 to 160° C. to perform a cellulose hydrolysis reaction.

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