Continuous preparation method for preparing p-hydroxycinnamic acid product through lignocellulose hydrolysis

Abstract

The invention discloses a continuous preparation method for preparing a p-hydroxycinnamic acid product through lignocellulose hydrolysis, a high-pressure single-screw extruder is used as a reaction device, and the reaction device comprises a biomass feeding unit, a feed mixing module, a screw reaction unit, a heating module, a product collecting unit and a cooling module. In the feeding unit, biomass is conveyed into a mixing module through a screw, is uniformly mixed with pumped alkali liquor and then is conveyed to a heated screw reaction area. The rotating speed of the screw is adjusted to control the reaction retention time, the reaction product is cooled in the collecting tank and collected into the product storage tank, the heat and mass transfer efficiency of the reaction process is improved by utilizing the transmission and mixing effects of the screw reactor, the hydrolysis preparation of the target product from the biomass can be completed within several minutes, the production efficiency of the target product is high, and the production cost is low. Continuous production is facilitated, the operation is simple, the labor cost is low, and technical support can be provided for producing ferulic acid and p-coumaric acid through high-value utilization of agricultural and forestry wastes.

Description

Technical Field

[0001] The invention belongs to the technical field of high-value utilization of biomass, and relates to an efficient preparation process technology of p-hydroxycinnamic acid products (ferulic acid and p-coumaric acid) in herbaceous plants, and in particular to a method for continuously hydrolyzing bagasse, corn stalks, reeds and straw in an alkaline environment to obtain p-hydroxycinnamic acid products, and specifically to a continuous preparation method for preparing p-hydroxycinnamic acid products by hydrolyzing lignocellulose. Background Art

[0002] Para-hydroxycinnamic acid derivatives, such as p-coumaric acid (4-hydroxycinnamic acid) and ferulic acid (4-hydroxy-3-methoxycinnamic acid), are widely found in the cell walls of herbaceous plants. As bifunctional molecules with carboxyl and phenolic functional groups, these phenolic acids are usually cross-linked with lignin and / or hemicellulose in ester or ether bonds, which are easily cleaved by alkali treatment. These naturally occurring molecules have excellent properties and values, such as antioxidant, anticancer and antimicrobial activities, making them valuable in food preservation and cosmetic industries. They are also used as building blocks for the synthesis of various chemical substances, such as polymers, adhesives, coatings and pharmaceuticals.

[0003] Natural ferulic acid and p-coumaric acid are expensive. These products are mainly extracted from rice bran, and the supply of raw materials is limited. In order to improve the economy of the production process, herbal agricultural waste biomass can be used as a potential production raw material. The alkaline hydrolysis method is suitable for processing biomass to extract p-hydroxycinnamic acid products. It has wide applicability and a simple processing process. In previous application cases, it was mainly prepared in an alkaline solvent system through a batch reaction device. However, this process usually requires a long reaction time to fully extract p-hydroxycinnamic acid products, and the long cooling process is prone to product degradation. In addition, the batch process is cumbersome to operate and has low production efficiency, which is not conducive to large-scale production and application. Summary of the invention

[0004] The present invention provides a continuous preparation method for preparing p-hydroxycinnamic acid products by hydrolyzing lignocellulose. The method is a method for continuously producing ferulic acid and p-coumaric acid by alkaline hydrolysis using herbaceous biomass as a substrate. The present invention uses herbaceous agricultural and forestry waste biomass as a raw material, and adopts a continuous high-pressure single-screw reaction device to realize the continuous process of preparing p-hydroxycinnamic acid products by alkaline hydrolysis. The biomass raw material enters the mixing module through a feeding unit, and then is pre-mixed with a certain concentration of alkaline aqueous solution and reaction gas, and then transported into the reaction area through a screw blade. In this process, the ester bonds and ether bonds connecting the biomass cell wall with the p-hydroxycinnamic acid products are broken, and ferulic acid and p-coumaric acid can be effectively extracted. The continuous production method developed by this patent can greatly improve the preparation efficiency of p-hydroxycinnamic acid products, reduce manpower input and operating costs, and provide strong technical support for industrial-scale production.

[0005] The method is based on a screw-propelled high-pressure reaction device, including a feeding unit, a screw reaction unit, and a sample collection unit. The feeding unit has a stirring paddle and a feeding screw blade, the feeding screw blade is connected to a mixing module, and the solvent storage tank and the gas storage tank each have an interface connected to the mixing module; the screw reactor is equipped with an external heating module, and the end of the screw reactor is connected to a product receiving tank; the product receiving tank is equipped with a sampling port and a back pressure valve, and a cooling water coil is provided in the product receiving tank. The reaction residence time is controlled by adjusting the screw speed.

[0006] The present invention adopts the following technical solutions:

[0007] A continuous preparation method for preparing p-hydroxycinnamic acid products by hydrolyzing lignocellulose comprises the following steps:

[0008] (1) Using crushed and sieved herbaceous plant biomass as raw material, controlling the particle size of biomass particles within the range of 0.2-0.5 mm (e.g., 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm); adding the reaction raw materials into a feeding unit; then transferring the biomass from the feeding unit into a mixing module, controlling the biomass feeding rate within the range of 80-200 g / min;

[0009] (2) In the alkaline hydrolysis process, alkali solution is used as the reaction medium, and the concentration of the alkali solution is controlled to be 0.1M-2.5M (for example, 0.1M, 0.3M, 0.5M, 0.7M, 0.9M, 1.1M, 1.3M, 1.5M, 1.7M, 1.9M, 2.1M, 2.3 M or 2.5M); adding alkali solution into the mixing module, and controlling the liquid inlet volume within 200-1000ml / min (for example, 200ml / min, 250ml / min, 300ml / min, 350ml / min, 400ml / min, 450ml / min, 500ml / min, 550ml / min, 600ml / min, 650ml / min, 700ml / min, 750ml / min, 800ml / min, 850ml / min, 900ml / min, 950ml / min or 1000ml / min); mixing the alkali solution and the biomass particles uniformly to obtain a mixed reactant; for example, the alkali is one or more of sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.

[0010] (3) The mixed reactants enter a preheated screw reaction zone under the transmission of the screw for continuous reaction. During the continuous reaction, the temperature of the reaction zone is set in the range of 50°C to 150°C (for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C), the gas pressure is set in the range of 0.3MPa to 1.5MPa (for example, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, 1.1MPa, 1.2MPa, 1.3MPa, 1.4MPa or 1.5MPa), and the screw speed is controlled to be 10-20rpm (for example, 10rpm, 11rpm, 13rpm, 15rpm, 17rpm, 19rpm or 20rpm).

[0011] Furthermore, in step (1), the herbaceous biomass is bagasse, corn stalks, reeds or straw.

[0012] Furthermore, in step (3), the gas is air or nitrogen.

[0013] Furthermore, in step (3), the residence time of the mixed reactants in the reaction area is 1 to 10 min (e.g., 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min).

[0014] Furthermore, the method further comprises step (4), wherein the reaction liquid enters the sample liquid collection tank along the direction of the screw pushing, and after the product is completely cooled to room temperature, the discharge valve is opened to transfer the sample liquid to the sample storage tank. For example, the reaction liquid enters the sample liquid collection tank along the direction of the screw pushing, the water flow rate of the cooling coil is adjusted to 200-800 ml / min, and after the product is completely cooled, the discharge valve is opened to transfer the sample liquid to the sample storage tank.

[0015] Specifically, the present invention proposes a method for producing ferulic acid and p-coumaric acid by continuous alkaline hydrolysis using herbal biomass as a substrate, and the specific implementation includes the following steps:

[0016] (1) Using crushed and sieved sugarcane bagasse, corn stalks, reeds, straw and other herbaceous plants as substrates, the particle size of biomass particles is controlled within the range of 0.2-0.5 mm; the reaction raw materials are added to the feeding unit, and are transmitted into the mixing module through the stirring paddle and the feeding screw blade, and the biomass feeding rate is controlled within the range of 80-200 g / min.

[0017] (2) The alkaline hydrolysis process uses an alkaline aqueous solution as the reaction medium, and the alkali concentration is controlled within the range of 0.1M-2.5M; the alkaline aqueous solution is added to the mixing module through a plunger pump, and the alkaline aqueous solution inlet volume is controlled at 200-1000ml / min, and is fully mixed with the solid biomass particles under the stirring of the screw blade.

[0018] (3) The mixed reactants enter the preheated reaction area under the transmission of the screw. During the continuous reaction, the temperature is set in the range of 50°C to 150°C, the gas pressure is set in the range of 0.3MPa to 1.5MPa, and the screw speed is controlled to be 5~40rpm;

[0019] (4) The reaction liquid enters the sample liquid collection tank along the screw pushing direction. Adjust the cooling coil water flow rate at 200-800 ml / min. After the product is completely cooled to room temperature, open the release valve to transfer the sample liquid to the sample storage tank.

[0020] Beneficial effects of the present invention:

[0021] The present invention proposes a continuous preparation method for preparing a hydroxycinnamic acid product by hydrolyzing lignocellulose. The method utilizes the efficient heat and mass transfer effects of a screw reaction device and pressurizes the system by external gas, which can accelerate the cracking of biomass components and the extraction of target products. The target product can be prepared by hydrolysis from biomass within a few minutes, and the target product production efficiency is high. The residence time of the product during the reaction is controlled by adjusting the screw speed, and the reaction residence time is optimized to avoid excessive degradation of the prepared product. The method is conducive to continuous production, simple to operate, and low in labor cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of the present invention.

[0023] 1. Feed unit, 2. Screw reactor, 3. Heating module, 4. Sample collection area, 5. Motor, 6. Gas storage tank, 7. Solvent storage tank, 8. Sample storage tank, 9. Condensation device, 10. Mixing module. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The present invention will be further described in detail below in conjunction with specific embodiments, and these embodiments are only for the purpose of illustrating the present invention, but the present invention is not limited to the following embodiments.

[0025] A method for producing ferulic acid and p-coumaric acid by continuous alkaline hydrolysis using herbal biomass as a substrate. The continuous reaction device used in the process of the present invention is a screw-propelled high-pressure reaction device, and the screw-propelled high-pressure reaction device is a high-pressure single-screw extruder, such as Figure 1 As shown, it includes a feeding unit 1, a screw reactor 2, a heating module 3, a sample collection area 4, a motor 5, a gas storage tank 6, a solvent storage tank 7, a sample storage tank 8, a condensing device 9 and a mixing module 10. Among them, the bottom of the feeding unit 1 is connected to the mixing module 10, the gas storage tank 6 is connected to the mixing module 10, and the solvent storage tank 7 is connected to the mixing module 10. The mixing module 10 is connected to the feeding port of the screw reactor 2. The outside of the screw reactor 2 is wrapped with a heating module 3. One end of the screw reactor 2 is connected to the motor 5, and the other end is connected to the sample collection area 4. The top outlet of the sample collection area 4 is connected to the top of the feeding unit 1. The lower side of the sample collection area 4 is connected to the condensing device 9. The top of the condensing device 9 is connected to the upper side of the sample collection area 4. The bottom of the sample collection area 4 is connected to the sample storage tank 8. A stirring paddle and a feeding screw blade are arranged inside the feeding unit 1. The solvent storage tank 7 contains an alkaline aqueous solution. A plunger pump (not shown in the figure) is arranged on the pipeline connecting the solvent storage tank 7 and the mixing module 10. The mixing module 10 is provided with a screw blade for stirring. The screw reactor 2 is provided with a screw. The sample collection area 4 is a product receiving tank. The product receiving tank is a sample liquid collection tank. The product receiving tank is equipped with a sampling port and a back pressure valve, and a cooling water coil is provided in the product receiving tank. The cooling water coil and the condensing device 9 are used to cool the product to room temperature. The gas storage tank 6 is a gas cylinder.

[0026] Using crushed and sieved sugarcane bagasse, corn stalks, reeds, straw and other herbaceous plants as substrates, the particle size of biomass particles is controlled within the range of 0.2-0.5mm; the reaction raw materials are added to the feeding unit 1, and are transmitted into the mixing module 10 through the stirring paddle and the feeding screw blade, and the biomass feeding rate is controlled within the range of 80-200g / min. The alkaline hydrolysis process uses alkaline aqueous solution as the reaction medium, and the alkali concentration is controlled within the range of 0.1M-2.5M; the alkaline aqueous solution is added to the mixing module 10 through a plunger pump, and the alkaline aqueous solution inlet is controlled at 200-1000ml / min, and is fully mixed with the solid biomass particles under the stirring of the screw blade. Start the motor 5. The mixed reactants enter the pre-heated reaction area (i.e., the inside of the screw reactor 2) under the transmission of the screw. During the continuous reaction, the temperature is set in the range of 50°C~150°C, the gas pressure is set in the range of 0.3MPa~1.5MPa, and the screw speed is controlled to be 5~40rpm; the reaction liquid enters the sample liquid collection tank along the pushing direction of the screw, and the water flow rate of the cooling coil is adjusted to 200-800ml / min. After the product is completely cooled to room temperature, the release valve is opened to transfer the sample liquid to the sample storage tank 8.

[0027] The following is an example of the aromatic monomer yield and cellulose retention rate under different reaction conditions:

[0028] Example 1: Using sugarcane bagasse with a particle size of 0.5 mm as raw material, the biomass feed rate is 100 g / min, the 2M NaOH solution feed rate is 800 ml / min, the nitrogen pressure is 1.5 MPa, the reaction zone temperature is 90°C, the screw speed is 20 rpm, and the material residence time in the reaction zone is 2 min. The reaction products are quantitatively analyzed by liquid chromatography, and the relevant product yield data are calculated and shown in Table 1.

[0029] Example 2: Corn stalks were selected as the reaction substrate, and the reaction materials and reaction conditions were the same as those in Example 1. The relevant product yield data were calculated and shown in Table 1.

[0030] Example 3: The reaction temperature was set at 120°C, the reaction materials and reaction conditions were the same as in Example 1, and the relevant product yield data were calculated and shown in Table 1.

[0031] Example 4: Corn stalks were selected as the reaction substrate, the reaction temperature was set to 120°C, the reaction materials and reaction conditions were the same as in Example 1, and the relevant product yield data were calculated and shown in Table 1.

[0032] Example 5: Reed was selected as the reaction substrate, the reaction temperature was set to 120°C, the reaction materials and reaction conditions were the same as in Example 1, and the relevant product yield data were calculated and shown in Table 1.

[0033] Example 6: The reaction temperature was set at 150°C, the reaction materials and reaction conditions were the same as in Example 1, and the relevant product yield data were calculated and shown in Table 1.

[0034] Table 1 Yields of ferulic acid and p-coumaric acid under different temperatures and substrate conditions

[0035]

[0036] Example 7: Using sugarcane bagasse with a particle size of 0.5 mm as raw material, the biomass feed rate is 100 g / min, the 2M NaOH solution feed rate is 800 ml / min, the air pressure is 0.4 MPa, the reaction zone temperature is 70°C, the screw speed is 20 rpm, and the material residence time in the reaction zone is 2 min. The reaction products are quantitatively analyzed by liquid chromatography, and the relevant product yield data are calculated and shown in Table 2.

[0037] Example 8: The reaction temperature was set at 90°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0038] Example 9: The reaction temperature was set at 120°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0039] Example 10: Corn stalks were selected as the reaction substrate, and the reaction materials and reaction conditions were the same as those in Example 7. The relevant product yield data were calculated and shown in Table 2.

[0040] Example 11: Corn stalks were selected as the reaction substrate, the reaction temperature was set to 90°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0041] Example 12: Corn stalks were selected as the reaction substrate, the reaction temperature was set to 120°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0042] Example 13: Reed was selected as the reaction substrate, the reaction temperature was set to 90°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0043] Example 14: Rice straw was selected as the reaction substrate, the reaction temperature was set to 90°C, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0044] Example 15: The base concentration was set to 0.1 M, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0045] Example 16: The base concentration was set to 0.5 M, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0046] Example 17: The base concentration was set to 1.0 M, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0047] Example 18: The reaction temperature was set at 50°C, the alkali concentration was set at 0.5M, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0048] Example 19: The reaction temperature was set at 90°C, the alkali concentration was set at 0.5M, the reaction materials and reaction conditions were the same as in Example 7, and the relevant product yield data were calculated and shown in Table 2.

[0049] Table 2 Yields of ferulic acid and p-coumaric acid under different temperatures, base concentrations and substrate conditions

[0050]

[0051] Example 20: Using sugarcane bagasse with a particle size of 0.5 mm as raw material, the biomass feed rate is 300 g / min, the 2M NaOH solution feed rate is 800 ml / min, the air pressure is 0.4 MPa, the reaction zone temperature is 120°C, the screw speed is 20 rpm, and the material residence time in the reaction zone is 2 min. The reaction products are quantitatively analyzed by liquid chromatography, and the relevant product yield data are calculated and shown in Table 3.

[0052] Example 21: The alkali concentration was set to 0.5 M, the reaction temperature was set to 70° C., the reaction materials and reaction conditions were the same as in Example 20, and the relevant product yield data were calculated and shown in Table 3.

[0053] Example 22: The base concentration was set to 1.0 M, the reaction temperature was set to 70°C, the reaction materials and reaction conditions were the same as in Example 20, and the relevant product yield data were calculated and shown in Table 3.

[0054] Example 23: Corn stalks were selected as the reaction substrate, the reaction temperature was set to 90°C, the reaction feed and reaction conditions were the same as in Example 20, and the relevant product yield data were calculated and shown in Table 3.

[0055] Example 24: Reed was selected as the reaction substrate, the reaction temperature was set to 90°C, the reaction materials and reaction conditions were the same as in Example 20, and the relevant product yield data were calculated and shown in Table 3.

[0056] Table 3 Yields of ferulic acid and p-coumaric acid under different substrates, temperatures and base concentrations at high solid-liquid ratios

[0057]

[0058] The present invention does not elaborate on some of the common technologies of those skilled in the art. The above-described embodiments are only descriptions of preferred implementations of the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementations described. Without departing from the design spirit of the present invention, various modifications and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A continuous preparation method for preparing p-hydroxycinnamic acid products by hydrolyzing lignocellulose, characterized in that: The following steps are involved: (1) Using crushed and sieved herbaceous plant biomass as raw material, controlling the biomass particle size within the range of 0.2-0.5 mm; adding the reaction raw materials into the feeding unit; then transferring the biomass from the feeding unit into the mixing module, controlling the biomass feeding rate within the range of 80-200 g / min; (2) In the hydrolysis process, an alkaline solute aqueous solution is used as a reaction medium, and the concentration of the alkaline solute is controlled within the range of 0.1M-2.5M; the alkaline solute aqueous solution is added to the mixing module through a pressure pump, and the liquid inlet volume is controlled at 200-1000ml / min; the alkaline solute aqueous solution and the biomass particles are evenly mixed to obtain a mixed reactant; (3) The mixed reactants enter the preheated screw reaction zone under the transmission of the screw for continuous reaction. During the continuous reaction, the temperature of the reaction zone is set in the range of 50°C to 150°C, the gas pressure is set in the range of 0.3MPa to 1.5MPa, and the screw speed is controlled to be 10 to 20rpm.

2. The method according to claim 1, characterized in that In step (1), the herbaceous biomass is bagasse, corn stalks, reeds or straw, and the biomass particle size is controlled within the range of 0.3-0.5 mm.

3. The method according to claim 1, characterized in that In step (1), the biomass feed rate is controlled at 80-190 g / min.

4. The method according to claim 1, characterized in that In step (2), the concentration of the alkaline solute is in the range of 0.2M-2.5M, and the alkaline solute is one or more of sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.

5. The method according to claim 1, characterized in that In step (2), the inflow rate of the alkaline solute aqueous solution is controlled at 500-950 ml / min to reduce the viscous resistance during the flow process.

6. The method according to claim 1, characterized in that In step (3), during the reaction process, the temperature of the screw reaction zone is 50°C to 140°C, the reaction pressure is 0.4MPa to 1.4MPa, and the screw speed is 10 to 19rpm.

7. The method according to claim 1, characterized in that In step (3), the gas is air or nitrogen.

8. The method according to claim 1, characterized in that In step (3), the residence time of the mixed reactants in the reaction area is 1 to 10 minutes.

9. The method according to claim 1, characterized in that: The method further comprises step (4), wherein the reaction liquid enters a sample liquid collection tank along the direction of the screw pushing, and after the product is completely cooled to room temperature, a release valve is opened to transfer the sample liquid to the sample storage tank.

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