CN110078946B - Method for quickly dissolving chitosan by acidic ionic liquid at low temperature - Google Patents
Method for quickly dissolving chitosan by acidic ionic liquid at low temperature Download PDFInfo
- Publication number
- CN110078946B CN110078946B CN201910416451.6A CN201910416451A CN110078946B CN 110078946 B CN110078946 B CN 110078946B CN 201910416451 A CN201910416451 A CN 201910416451A CN 110078946 B CN110078946 B CN 110078946B
- Authority
- CN
- China
- Prior art keywords
- ionic liquid
- acidic ionic
- chitosan
- alkyl
- methyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
- C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
- C08J3/11—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids from solid polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2305/00—Characterised by the use of polysaccharides or of their derivatives not provided for in groups C08J2301/00 or C08J2303/00
- C08J2305/08—Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Abstract
The invention discloses a method for quickly dissolving chitosan by acidic ionic liquid at low temperature; the invention prepares the acid ionic liquid containing the sulfonate, uses the aqueous solution of the acid ionic liquid containing the sulfonate as a solvent, and quickly dissolves chitosan with different molecular weights at low temperature; the acidic ionic liquid is as follows: an acidic ionic liquid containing sulfonate derived from an alkyl imidazole or alkyl pyridine compound; the acidic ionic liquid only dissolves chitosan, and cannot cause the hydrolysis of the chitosan; the method has the advantages of simple operation, no pollution, low dissolving temperature, high dissolving speed and obviously improved solubility of the chitosan compared with the common ionic liquid. The invention provides a new scheme for the pretreatment of chitin, chitin and chitosan.
Description
Technical Field
The invention belongs to the field of pretreatment processes of chitin, chitin and chitosan, and particularly relates to a method for quickly dissolving chitosan in acidic ionic liquid at a low temperature and preparation of the acidic ionic liquid.
Background
Nowadays, mineral resources are increasingly in short supply and environmental pollution is increasingly severe, people gradually turn attention to renewable green resources in nature. The aquaculture industry and shrimp and crab processing all over the world generate a lot of shell solid wastes. These shell wastes are important resources for preparing Chitin (Chitin). Chitosan (Chitosan) is obtained by deacetylating chitin, and has a chemical name of (1-4) -2-acetamido-B-D glucose. Because chitosan is rich in nature, easily available in raw materials, safe and nontoxic, has excellent characteristics of good biocompatibility, antibacterial property, biodegradability and the like, and is widely applied to the fields of medicine, biotechnology, chemical industry, cosmetics, feed, agriculture, environmental protection, biomedicine, genetic disease treatment and the like. However, the chitosan has a large number of hydrogen bonding effects in the molecule, which results in poor swelling resistance and solubility of chitosan, and poor solubility in conventional organic solvents, thus greatly limiting the wide application of chitosan.
The dissolution of chitosan is an important prerequisite for realizing the industrial application of the chitosan, and the wide application of the chitosan can be greatly limited if the chitosan is not dissolved into a homogeneous liquid. Therefore, efficient dissolution of chitosan is currently the most problematic issue to be solved. Most of the traditional methods for dissolving chitosan use direct solvents of chitosan, including lithium salt-strong polar aprotic polar solvent system, alkali-ice mixture solvent system, strong polar fluorine-containing solvent (hexafluoroisopropanol), alkali/urea or thiourea/water solvent system, strong polar protic solvent system, calcium chloride-methanol solvent system, and dilute acid solvent system (acetic acid, trifluoroacetic acid, etc.), but these direct solvents have the disadvantages of high toxicity, strong corrosivity, troublesome post-treatment, low dissolution efficiency, harsh dissolution conditions, etc.
Ionic Liquids (ILs) are a class of excellent solvents with great application prospects, and are widely applied to the fields of organic synthesis, catalysis, analytical chemistry, electrochemistry, chemical separation and the like. Since the first time that Swatloski reported the solubility of ionic liquids to cellulose in 2002, the study of ionic liquid solubility modification in biomacromolecules (cellulose, starch, chitosan) was very intense (Journal of the American Chemical Society, 2002, 124: 4974-.
In 2006, Xie et al firstly applied [ Bmim ] Cl to dissolve chitosan, 10% of chitosan can be completely dissolved by [ Bmim ] Cl at 110 ℃ for 5h, and proposed the mechanism that the chitosan dissolution is caused by the destruction of hydrogen bonds in chitosan molecules by ionic liquid (Green Chemistry, 2006, 8: 630-. Thereafter, many conventional ionic liquids, such as [ Amim ] Cl, [ Bmim ] Cl, [ Etmim ] Cl, [ Emim ] Ac and [ Bmim ] Ac, were investigated for dissolution using chitosan (Carbohydrate Polymers, 2011, 83: 233-. But has the problems of low dissolving efficiency, high dissolving temperature (more than or equal to 80 ℃), long dissolving time, easy chitosan hydrolysis and the like. Therefore, a novel and efficient environment-friendly solvent system is found to dissolve chitosan, and industrialization of chitosan are greatly promoted.
Acidic Ionic Liquids (AILs) are a branch of functionalized ionic liquids, and have both Acidic and ionic liquid properties. However, strong acids such as sulfuric acid, methanesulfonic acid, hydrochloric acid, nitric acid, etc. are often used in the preparation of acidic ionic Liquids, and the presence of strongly acidic components inevitably causes problems such as hydrolysis, degradation, and oxidative carbonization of solutes (cellulose, lignin, chitosan, 2016, 218: 95-105; ChemSusChem, 2015, 8: 947-.
Disclosure of Invention
A method for rapidly dissolving chitosan at low temperature by using acidic ionic liquid comprises the steps of taking an aqueous solution containing sulfonate acidic ionic liquid as a solvent, and dissolving chitosan at the temperature of 20-40 ℃, wherein the chitosan accounts for 1-10% of the solvent by mass percent; the sulfonate-containing acidic ionic liquid comprises alkyl imidazole acidic ionic liquid and alkyl pyridine acidic ionic liquid, and the structural formula of the acidic ionic liquid is as follows:
alkyl imidazole acidic ionic liquid
Alkyl pyridine acidic ionic liquid
Wherein R ═ methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, hexadecyl;
R1methyl, ethyl;
R22-methyl, 3-methyl, 4-methoxy, 3-ethyl, 4-ethyl, 3-butyl;
the preparation method of the acidic ionic liquid containing the sulfonate comprises the following two steps:
(1) preparation of sulfonic acid inner salt:
taking an alkyl imidazole compound and sultone as raw materials, reacting for 4-12h at-5-60 ℃ in a low-polarity aprotic organic solvent, and synthesizing to obtain an alkyl imidazole sulfonic acid inner salt;
taking an alkyl pyridine compound and sultone as raw materials, reacting for 4-12h at-5-60 ℃ in a low-polarity aprotic organic solvent, and synthesizing to obtain an alkyl pyridine sulfonic acid inner salt;
(2) preparing the acidic ionic liquid containing the sulfonate:
mixing the alkyl imidazole sulfonic acid inner salt obtained in the step with acetic acid or propionic acid, and reacting for 2-6h at 20-40 ℃ to obtain the alkyl imidazole acidic ionic liquid.
Mixing the alkyl pyridine sulfonic acid inner salt obtained in the step with acetic acid or propionic acid, and reacting for 2-6h at 20-40 ℃ to obtain the alkyl pyridine acidic ionic liquid.
Preferably, the low-polarity aprotic organic solvent is one or two mixed solvents of dichloromethane, petroleum ether, n-hexane and cyclohexane.
Preferably, the molar ratio of the alkyl imidazole sulfonic acid inner salt to the acetic acid or the propionic acid is 1 to (1-9), and the molar ratio of the alkyl pyridine sulfonic acid inner salt to the acetic acid or the propionic acid is 1 to (1-9).
Preferably, the mass ratio of the sulfonate-containing acidic ionic liquid to the water is (5-60) to (40-95).
The invention has the remarkable advantages that:
(1) the preparation process of the sulfonate-containing acidic ionic liquid is simple, and the yield is high;
(2) the aqueous solution of the acidic ionic liquid containing the sulfonate has low viscosity and proper pH value;
(4) the method is simple to operate, free of pollution, low in chitosan dissolving temperature and high in dissolving speed, and the solubility of chitosan is remarkably improved compared with that of common ionic liquid;
(5) the solvent system only realizes the dissolution of the chitosan, the hydrolysis of the chitosan cannot be caused, and the molecular weight and the deacetylation degree of the regenerated chitosan are small in change.
Drawings
FIG. 1 is a schematic diagram of the structure of an acidic ionic liquid containing sulfonate;
FIG. 2 mPSAC nuclear magnetic hydrogen spectrum;
FIG. 3 metallography microscope photograph of chitosan dissolution (50 times magnification, left is before dissolution, right is after mPSAC dissolution);
FIG. 4 thermogravimetric analysis (mPSAC dissolution and regeneration) of regenerated chitosan.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Example 1
1-methyl-3- (propyl-3-sulfonic acid) imidazolium salt (mPSO)3) Synthesis of (2)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of propyl sultone, carrying out ice bath cooling under continuous stirring, slowly dripping 0.1mol of N-methylimidazole at constant pressure, slowly heating after dripping, reacting at normal temperature for 2 hours, carrying out suction filtration, washing a solid with ethyl acetate for 3 times, removing excessive propyl sultone and dichloromethane, drying at 80 ℃ for 2 hours, and obtaining a white solid, namely mPSO3The yield is 99 percent, the melting point is 227 ℃, and the nuclear magnetic hydrogen spectrum confirms the structure;
the reaction equation is as follows:
synthesis of 1-methyl-3- (propyl-3-sulfonic) imidazole acetate (mPSAC)
The product of the first step (mPSO)3) Adding acetic acid (molar ratio is 1: 3) into a four-mouth bottle, stirring at normal temperature, and gradually forming a homogeneous viscous liquid, namely the acidic ionic liquid (mPSAC), wherein the yield is 100%, and the nuclear magnetic hydrogen spectrum confirms the structure; the reaction equation is as follows:
mPSO3nuclear magnetic hydrogen spectrum (D)2O)：2.21ppm(m，2H)，2.82ppm(t，2H)，3.79ppm(s，3H，-NCH3)，4.26ppm(t，2H)，7.34ppm(t，1H，-NCH)，7.42ppm(t，1H，-NCH)，8.65ppm(s，1H，-NCHN-).
Nuclear magnetism of mPSACHydrogen spectrum (D)2O)：1.96ppm(s，9H，CH3COO-)，2.19ppm(m，2H)，2.80ppm(t，2H)，3.77ppm(s，3H，-NCH3)，4.24ppm(t，2H)，7.32ppm(t，1H，-NCH)，7.40ppm(t，1H，-NCH)，8.64ppm(s，1H，-NCHN-).
The physical parameters of the acidic ionic liquid, such as density, pH value, viscosity, Hammett acidity (H), are determined by testing0) Kamlet-Taft parameters (values of β and polarizability π) are shown in Table 1.
Weighing 5g of mPSAC and 95g of deionized water, dissolving to form a 5% acidic ionic liquid aqueous solution, weighing 1.02g (mass percentage of 1%) of chitosan with the molecular weight of about 6.04 × 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 20 ℃, observing by a metallographic microscope (figure 3), and stirring for 48min to form a homogeneous solution, which indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 80mL of 0.2mol/L NaOH solution to adjust pH to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing with deionized water for 3 times, detecting pH to be approximately equal to 7 with test paper, drying the chitosan for 2h at 80 ℃, weighing, measuring m to be approximately equal to 0.3g, and testing the molecular weight and the deacetylation degree of the regenerated chitosan (Table 3);
example 2
1-butyl-3- (propyl-3-sulfonic) imidazolium salt (bPSO)3) Synthesis of (2)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of propyl sultone, carrying out ice bath cooling under continuous stirring, slowly dripping 0.1mol of N-butylimidazole at constant pressure, slowly heating after dripping, reacting at normal temperature for 2 hours, carrying out suction filtration, washing a solid with ethyl acetate for 3 times, removing excessive propyl sultone and dichloromethane, drying at 80 ℃ for 2 hours, and obtaining a white solid, namely bPSO3The yield is 99%, the melting point is 179 ℃, and the nuclear magnetic hydrogen spectrum confirms the structure;
synthesis of 1-butyl-3- (propyl-3-sulfonic) imidazole acetate (bPSAc)
The first step product (bPSO)3) Adding acetic acid (molar ratio is 1: 3) into a four-mouth bottle, stirring at normal temperature, and gradually forming a homogeneous viscous liquid, namely acidic ionic liquid (bPSAc), wherein the yield is 100 percent and the nuclear magnetic hydrogen spectrum confirms the structure; the reaction equation is as follows:
bPSO3nuclear magnetic hydrogen spectrum (D)2O)：0.82ppm(t，3H)，1.20ppm(m，2H)，1.75ppm(m，2H)，2.22ppm(m，2H)，2.82ppm(t，2H)，4.11ppm(t，2H，-NCH2)，4.27ppm(t，2H)，7.42ppm(t，1H，-NCH)，7.44ppm(t，1H，-NCH)，8.73ppm(s，1H，-NCHN-).
Nuclear magnetic hydrogen spectrum (D) of bPSAc2O)：0.81ppm(t，3H)，1.20ppm(m，2H)，1.75ppm(m，2H)，1.98ppm(s，9H，CH3COO-)，2.22ppm(m，2H)，2.81ppm(t，2H)，4.10ppm(t，2H，-NCH2)，4.26ppm(t，2H)，7.41ppm(t，1H，-NCH)，7.44ppm(t，1H，-NCH)，8.72ppm(s，1H，-NCHN-).
The test determines the physical parameters of the acidic ionic liquid, such as density, pH value, viscosity, Hammett acidity (H)0) Kamlet-Taft parameters (values of β and polarizability π) are shown in Table 1.
Weighing 10g of bPSAc and 90g of deionized water, dissolving to form 10% acidic ionic liquid aqueous solution, weighing 3.02g (3% by mass) of chitosan with the molecular weight of about 6.04 × 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 20 ℃, observing by a metallographic microscope (figure 3), and stirring for 55min to form homogeneous solution, which shows that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in the bPSAc aqueous solution), adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 80mL of 0.2mol/L NaOH solution to adjust the pH value to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing for 3 times with deionized water, detecting the pH value to be approximately equal to 7 with test paper, drying the chitosan for 2h at 80 ℃, weighing, measuring the m to be approximately equal to 0.3g, and testing the molecular weight and the deacetylation degree of the regenerated chitosan, wherein the regeneration rate is approximately 76%;
example 3
Synthesis of 1-methyl-3- (butyl-4-sulfonate) imidazole salt (mBSO3)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of butyl sultone, carrying out ice bath cooling under continuous stirring, slowly dripping 0.1mol of N-methylimidazole at constant pressure, slowly heating after dripping, reacting for 3 hours at 25 ℃, carrying out suction filtration, washing the solid for 3 times by using ethyl acetate, removing excessive butyl sultone and dichloromethane, and drying to obtain a white solid, namely mBSO3The yield is 98 percent, the melting point is 216 ℃, and the nuclear magnetic hydrogen spectrum confirms the structure.
The product has the following structural formula:
synthesis of 1-methyl-3- (butyl-4-sulfo) imidazole acetate (mBSAc)
The product of the first step (mBSO)3) Adding acetic acid (molar ratio is 1: 3) into a four-mouth bottle, stirring at normal temperature, and gradually forming a homogeneous viscous liquid, namely acidic ionic liquid (mBSAc), wherein the yield is 100 percent and the nuclear magnetic hydrogen spectrum confirms the structure; the product has the following structural formula:
mBSO3nuclear magnetic hydrogen spectrum (D)2O)：2.08ppm(m，2H)，2.18ppm(m，2H)，3.07ppm(t，2H)，4.00ppm(s，3H，-NCH3)，4.38ppm(t，2H)，7.55ppm(m，1H，-NCH)，7.61ppm(m，1H，-NCH)，8.83ppm(s，1H，-NCHN-).
Nuclear magnetic hydrogen spectrum (D) of mbs ac2O)：1.87ppm(s，9H，CH3COO-)，2.04ppm(m，2H)，2.13ppm(m，2H)，3.02ppm(t，2H)，3.96ppm(s，3H，-NCH3)，4.30ppm(t，2H)，7.50ppm(m，1H，-NCH)，7.58ppm(m，1H，-NCH)，8.81ppm(s，1H，-NCHN-).
Test determinationPhysical parameters of the acidic ionic liquid, such as density, pH value, viscosity, Hammett acidity (H)0) Kamlet-Taft parameters (β values and polarizability pi), see table 1;
weighing 5g of mPSAC and 95g of deionized water, dissolving to form a 5% acidic ionic liquid aqueous solution, weighing 2.01g (mass percentage is 2%) of chitosan with the molecular weight of about 6.04 x 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 20 ℃, observing by a metallographic microscope (figure 3), and stirring for 52min to form a homogeneous solution, which shows that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 80mL of 0.2mol/L NaOH solution to adjust pH to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing for 3 times with deionized water, detecting pH to be approximately equal to 7 with test paper, drying for 2h at the temperature of 80 ℃ for chitosan, weighing, measuring m to be approximately equal to 0.3g, and testing the molecular weight and the deacetylation degree of the regenerated chitosan, wherein the regeneration rate is approximately 75%;
example 4
1-butyl-3- (butyl-4-sulfonic) imidazolium salt (bBSO)3) Synthesis of (2)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of butyl sultone, carrying out ice bath cooling under continuous stirring, slowly dripping 0.1mol of N-butylimidazole at constant pressure, slowly heating after dripping, reacting for 3 hours at 25 ℃, carrying out suction filtration, washing a solid for 3 times by using ethyl acetate, removing excessive butyl sultone and dichloromethane, and drying to obtain a white solid, namely bBSO3The yield is 98 percent, the melting point is 152 ℃, and the nuclear magnetic hydrogen spectrum confirms the structure;
the product has the following structural formula:
synthesis of 1-butyl-3- (butyl-4-sulfo) imidazole acetate (bBSAc)
The product of the first step (bBSO)3) Adding acetic acid (molar ratio of 1: 3) into a four-mouth bottle, stirring at normal temperature, gradually forming a homogeneous viscous liquid, namely acidic ionic liquid (bBSAc), and collectingThe rate is 100%, and the nuclear magnetic hydrogen spectrum confirms the structure; the product has the following structural formula:
bBSO3nuclear magnetic hydrogen spectrum (D20): 0.79ppm (t, 3H), 1.18ppm (m, 2H), 1.76ppm (m, 2H), 2.09ppm (m, 2H), 2.23ppm (m, 2H), 2.84ppm (t, 2H), 4.15ppm (t, 2H, -NCH)2)，4.29ppm(t，2H)，7.46ppm(t，1H，-NCH)，7.57ppm(t，1H，-NCH)，8.82ppm(s，1H，-NCHN-).
Nuclear magnetic hydrogen spectrum (D) of bBSAc2O)：0.81ppm(t，3H)，1.20ppm(m，2H)，1.73ppm(m，2H)，1.97ppm(s，9H，CH3COO-)，2.12ppm(m，2H)，2.28ppm(m，2H)，2.87ppm(t，2H)，4.20ppm(t，2H，-NCH2)，4.36ppm(t，2H)，7.50ppm(t，1H，-NCH)，7.61ppm(t，1H，-NCH)，8.87ppm(s，1H，-NCHN-).
The test determines the physical parameters of the acidic ionic liquid, such as density, pH value, viscosity, Hammett acidity (H)0) Kamlet-Taft parameters (values of β and polarizability π) are shown in Table 1.
Weighing 5g of mPSAC and 95g of deionized water, dissolving to form a 5% acidic ionic liquid aqueous solution, weighing 3.04g (3% by mass) of chitosan with the molecular weight of about 6.04 × 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 20 ℃, observing by a metallographic microscope (figure 3), and stirring for 67min to form a homogeneous solution, wherein the homogeneous solution shows that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 80mL of 0.2mol/L NaOH solution to adjust pH to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing for 3 times with deionized water, detecting pH to be approximately equal to 7 with test paper, drying for 2h at the temperature of 80 ℃ for chitosan, weighing, measuring m to be approximately equal to 0.3g, and testing the molecular weight and the deacetylation degree of the regenerated chitosan, wherein the regeneration rate is approximately 75%;
TABLE 1 physical Properties of aqueous acidic Ionic liquids
TABLE 2 dissolution time (min) of chitosan in acidic ionic liquid aqueous solution
Example 5
Preparation of 1-methyl-3- (propyl-3-sulfonic) imidazole acetate (mPSAc) according to example 1; weighing 10g of mPSAC and 90g of deionized water to dissolve the mPSAC into a 10% acidic ionic liquid aqueous solution, weighing 2.03g (2% by mass) of chitosan with the molecular weight of about 6.04 x 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 25 ℃, observing by a metallographic microscope, and stirring for 42min to form a homogeneous solution, which indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 60mL of 0.3mol/L NaOH solution to adjust the pH value to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing with deionized water for 3 times, detecting the pH value to be approximately equal to 7 with test paper, drying the chitosan at 80 ℃ for 2h, weighing, and testing the molecular weight and the deacetylation degree of the regenerated chitosan;
example 6
Preparation of 1-methyl-3- (propyl-3-sulfonic) imidazole acetate (mPSAc) according to example 1; weighing 15g of mPSAC and 85g of deionized water to dissolve the mPSAC into a 15% acidic ionic liquid aqueous solution, weighing 2.03g (2% by mass) of chitosan with the molecular weight of about 6.04 x 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 25 ℃, observing by a metallographic microscope, and stirring for 48min to form a homogeneous solution, which indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 60mL of 0.3mol/L NaOH solution to adjust the pH value to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing with deionized water for 3 times, detecting the pH value to be approximately equal to 7 with test paper, drying the chitosan at 80 ℃ for 2h, weighing, and testing the molecular weight and the deacetylation degree of the regenerated chitosan;
dissolving chitosan with different mass ratios in 1-methyl-3- (propyl-3-sulfonic) imidazole acetate (mPSAC) acidic ionic liquid aqueous solutions (5% -60%) with different mass ratios, dissolving the chitosan at 25 ℃, recording the dissolving time (min), regenerating the chitosan by using a sodium hydroxide solution, and testing the molecular weight and the deacetylation degree of the regenerated chitosan; other conditions and operations were the same as in example 1; the results of the experiments of examples 5-14 are shown in Table 3.
TABLE 3 dissolution and regeneration performances of acidic ionic liquid aqueous solutions with different mass ratios on chitosan
Example 15
1-butyl-3- (propyl-3-sulfonic) imidazole acetate (bpnac) was prepared as in example 2; weighing 10g of bPSAc and 90g of deionized water to dissolve the bPSAc into a 10% acidic ionic liquid aqueous solution, weighing 2.03g (2% by mass) of chitosan with the molecular weight of about 6.04 x 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 25 ℃, observing by a metallographic microscope, and stirring for 35min to form a homogeneous solution, which indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPSAC aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 60mL of 0.3mol/L NaOH solution to adjust the pH value to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing with deionized water for 3 times, detecting the pH value to be approximately equal to 7 with test paper, drying the chitosan at 80 ℃ for 2h, weighing, and testing the molecular weight and the deacetylation degree of the regenerated chitosan;
dissolving chitosan with different mass ratios by adopting 1-butyl-3- (propyl-3-sulfonic group) imidazole acetate (bPSAc) acidic ionic liquid aqueous solutions (5% -60%) with different mass ratios, dissolving the chitosan at 25 ℃, recording the dissolving time (min), regenerating the chitosan by adopting a sodium hydroxide solution, and testing the molecular weight and the deacetylation degree of the regenerated chitosan; other conditions and operations were the same as in example 15; the results of the experiments for examples 16-25 are set forth in Table 4.
TABLE 4 dissolution and regeneration performance of acidic ionic liquid aqueous solution with different mass ratios on chitosan
Example 26
1-hexyl-3- (propyl-3-sulfonic) imidazolium salt (hPSO)3) Synthesis of (2)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of propyl sultone, adding 0.1mol of N-hexyl imidazole, slowly heating to 50 ℃, reacting for 2 hours, performing suction filtration, washing the solid with ethyl acetate for 3 times, removing excessive propyl sultone and dichloromethane, drying for 2 hours at 80 ℃, and obtaining a white solid, namely hPSO3Yield 98% and melting point 138 ℃;
synthesis of 1-hexyl-3- (propyl-3-sulfonic) imidazole acetate (hPSAC)
Subjecting the product of the first step (hPSO)3) Adding acetic acid (molar ratio is 1: 3) into a four-mouth bottle, stirring at normal temperature, and gradually forming a homogeneous viscous liquid, namely the acidic ionic liquid (hPSAC), with the yield of 100%;
weighing 5g of hPSAC and 95g of deionized water, dissolving to form a 5% acidic ionic liquid aqueous solution, weighing 1.02g (mass percentage of 1%) of chitosan with the molecular weight of about 6.04 x 106 g/mol and the deacetylation degree of 86.32%, stirring and mixing at 25 ℃, observing by a metallographic microscope, and stirring for 58min to form a homogeneous solution, wherein the homogeneous solution indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in hPSAC aqueous solution), adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 40mL of 0.3mol/L NaOH solution to adjust the pH value to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing for 3 times with deionized water, detecting the pH value to be approximately equal to 7 with test paper, drying for 2h at the temperature of 80 ℃, weighing, ensuring the regeneration rate to be approximately 75%, and testing the molecular weight and the deacetylation degree of the regenerated chitosan;
different alkyl imidazoles (raw material 1) and sultone (raw material 2) are adopted to prepare a series of alkyl imidazole acidic ionic liquid, and other conditions and operations are the same as those of example 26; the results of the preparations of examples 27 to 35 are shown in Table 5.
Table 5 preparation examples of alkyl imidazole acidic ionic liquids
Example 36
2-methyl-1- (propyl-3-sulfonic acid) pyridine salt (mPySO)3) Synthesis of (2)
Adding 80mL of dichloromethane into a four-neck flask, adding 0.105mol of propyl sultone, adding 0.1mol of 2-methylpyridine, reacting for 2h at normal temperature, filtering, washing the solid with ethyl acetate for 3 times, removing excessive propyl sultone and dichloromethane, drying for 2h at 80 ℃, and obtaining a white solid, namely mPySO3Yield 97%, melting point 178 ℃;
synthesis of 2-methyl-1- (propyl-3-sulfonic) pyridine acetate (mPySAc)
The product of the first step (mPySO)3) Adding acetic acid (molar ratio is 1: 3) into a four-mouth bottle, stirring at normal temperature, and gradually forming a homogeneous viscous liquid, namely the acidic ionic liquid (mPySAc), with the yield of 100%;
weighing 5g mPySAc and 95g deionized water to dissolve to form 5% acidic ionic liquid water solution, weighing molecular weight of about 6.04X 102.03g (2 percent by mass) of chitosan with the deacetylation degree of 86.32% at the concentration of 6g/mol, stirring and mixing at the temperature of 25 ℃, observing by a metallographic microscope, and stirring for 37min to form a homogeneous solution, which indicates that the chitosan is completely dissolved in the acidic ionic liquid aqueous solution;
weighing 40g of chitosan solution (chitosan is dissolved in mPySAc aqueous solution) and adding the chitosan solution into a three-mouth bottle, stirring at normal temperature, adding about 50mL of 0.3mol/L NaOH solution to adjust pH to be approximately equal to 7, continuously stirring for 30min, filtering with filter cloth, washing for 3 times with deionized water, detecting pH to be approximately equal to 7 with test paper, drying for 2h at 80 ℃, weighing, ensuring the regeneration rate to be approximately 75%, and testing the molecular weight and the deacetylation degree of regenerated chitosan;
different alkyl pyridine (raw material 1) and sultone (raw material 2) are adopted to prepare a series of alkyl pyridine acidic ionic liquid, and other conditions and operations are the same as those of the example 36; the results of the preparations of examples 37 to 49 are shown in Table 6.
Table 6 preparation examples of alkylpyridines acidic ionic liquids
Claims (4)
1. A method for quickly dissolving chitosan by acidic ionic liquid at low temperature is characterized in that: taking an aqueous solution containing a sulfonate acidic ionic liquid as a solvent, and dissolving chitosan at the temperature of 20-25 ℃ for 10-60min, wherein the chitosan accounts for 1-2% of the solvent by mass percent; the sulfonate-containing acidic ionic liquid comprises alkyl imidazole acidic ionic liquid and alkyl pyridine acidic ionic liquid, and the structural formula of the acidic ionic liquid is as follows:
alkyl imidazole acidic ionic liquid
Alkyl pyridine acidic ionic liquid
Wherein R ═ methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, hexadecyl;
R1methyl, ethyl;
R22-methyl, 3-methyl, 4-methyl, 3-ethyl, 4-ethyl, 3-butyl;
the preparation method of the acidic ionic liquid containing the sulfonate comprises the following two steps:
(1) preparation of sulfonic acid inner salt:
taking an alkyl imidazole compound and sultone as raw materials, reacting for 4-12h at-5-60 ℃ in a low-polarity aprotic organic solvent to synthesize an alkyl imidazole sulfonic acid inner salt, wherein alkyl in the alkyl imidazole compound is methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl and hexadecyl;
taking an alkyl pyridine compound and sultone as raw materials, reacting for 4-12h at-5-60 ℃ in a low-polarity aprotic organic solvent to synthesize an alkyl pyridine sulfonic acid inner salt, wherein alkyl in the alkyl pyridine compound is 2-methyl, 3-methyl, 4-methyl, 3-ethyl, 4-ethyl and 3-butyl; the sulfonic lactone is 1, 3-propane sulfonic lactone or 1, 4-butane sulfonic lactone;
(2) preparing the acidic ionic liquid containing the sulfonate:
mixing the alkyl imidazole sulfonic acid inner salt obtained in the step with acetic acid or propionic acid, and reacting for 2-6h at 20-40 ℃ to obtain alkyl imidazole acidic ionic liquid;
mixing the alkyl pyridine sulfonic acid inner salt obtained in the step with acetic acid or propionic acid, and reacting for 2-6h at 20-40 ℃ to obtain the alkyl pyridine acidic ionic liquid.
2. The method for rapidly dissolving chitosan at low temperature by using acidic ionic liquid as claimed in claim 1, wherein: the low-polarity aprotic organic solvent is one or two mixed solvents of dichloromethane, petroleum ether, n-hexane and cyclohexane.
3. The method for rapidly dissolving chitosan at low temperature by using acidic ionic liquid as claimed in claim 1, wherein: the molar ratio of the alkyl imidazole sulfonic acid inner salt to the acetic acid or the propionic acid is 1: 1-9, and the molar ratio of the alkyl pyridine sulfonic acid inner salt to the acetic acid or the propionic acid is 1: 1-9.
4. The method for rapidly dissolving chitosan at low temperature by using acidic ionic liquid as claimed in claim 1, wherein: the mass ratio of the sulfonate-containing acidic ionic liquid to water is (5-60) to (40-95).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910416451.6A CN110078946B (en) | 2019-05-17 | 2019-05-17 | Method for quickly dissolving chitosan by acidic ionic liquid at low temperature |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910416451.6A CN110078946B (en) | 2019-05-17 | 2019-05-17 | Method for quickly dissolving chitosan by acidic ionic liquid at low temperature |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110078946A CN110078946A (en) | 2019-08-02 |
| CN110078946B true CN110078946B (en) | 2022-06-07 |
Family
ID=67420754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910416451.6A Active CN110078946B (en) | 2019-05-17 | 2019-05-17 | Method for quickly dissolving chitosan by acidic ionic liquid at low temperature |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110078946B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110590869A (en) * | 2019-10-09 | 2019-12-20 | 山东润德生物科技有限公司 | Preparation method of N-acetylglucosamine |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101508675A (en) * | 2009-03-26 | 2009-08-19 | 浙江工业大学 | Novel disulfonic acid type alkyl imidazole ionic liquid, preparation and uses thereof |
| CN102134615A (en) * | 2010-12-30 | 2011-07-27 | 浙江师范大学 | Method for hydrolyzing chitin and chitosan |
| CN102168323A (en) * | 2011-02-24 | 2011-08-31 | 天津工业大学 | Method for preparing chitosan and chitin functional materials by taking ionic liquid as solvent |
| CN102295603A (en) * | 2011-06-08 | 2011-12-28 | 东南大学 | Peroxy heteropoly acid based ionic liquid and preparation method thereof |
| CN102702390A (en) * | 2012-07-02 | 2012-10-03 | 天津工业大学 | Method for preparing low molecular weight chitosan through acidic ionic liquid aqueous solution degradation method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101973940B (en) * | 2010-09-28 | 2012-10-03 | 盐城师范学院 | Continuously synthesizing method of sulfonic acid alkyl group ionic liquid |
| WO2014018586A1 (en) * | 2012-07-24 | 2014-01-30 | The Board Of Trustees Of The University Of Alabama | Process for electrospinning chitin fibers from chitinous biomass solution and fibers and articles produced thereby |
| CN105562081A (en) * | 2015-11-20 | 2016-05-11 | 陕西盛迈石油有限公司 | Preparation method of ionic liquid |
-
2019
- 2019-05-17 CN CN201910416451.6A patent/CN110078946B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101508675A (en) * | 2009-03-26 | 2009-08-19 | 浙江工业大学 | Novel disulfonic acid type alkyl imidazole ionic liquid, preparation and uses thereof |
| CN102134615A (en) * | 2010-12-30 | 2011-07-27 | 浙江师范大学 | Method for hydrolyzing chitin and chitosan |
| CN102168323A (en) * | 2011-02-24 | 2011-08-31 | 天津工业大学 | Method for preparing chitosan and chitin functional materials by taking ionic liquid as solvent |
| CN102295603A (en) * | 2011-06-08 | 2011-12-28 | 东南大学 | Peroxy heteropoly acid based ionic liquid and preparation method thereof |
| CN102702390A (en) * | 2012-07-02 | 2012-10-03 | 天津工业大学 | Method for preparing low molecular weight chitosan through acidic ionic liquid aqueous solution degradation method |
Non-Patent Citations (1)
| Title |
|---|
| 虾壳在1-乙基-3-甲基咪唑醋酸盐离子液体中的溶解特性;高静 等;《食品工业科技》;20180802;第39卷(第24期);第29-34页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110078946A (en) | 2019-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sharma et al. | Dissolution of α-chitin in deep eutectic solvents | |
| Wu et al. | A novel biomass-ionic liquid platform for the utilization of native chitin | |
| DK2585524T5 (en) | A method for dissolving lignocellulosic materials | |
| CN1261496C (en) | Cellulose solution and its preparing method | |
| US9394375B2 (en) | Compositions containing recyclable ionic liquids for use in biomass processing | |
| WO2007049485A1 (en) | Process for producing cellulose solution, cellulose solution, and process for producing regenerated cellulose | |
| EP2845874B1 (en) | Method for dissolving cellulose | |
| CN110078946B (en) | Method for quickly dissolving chitosan by acidic ionic liquid at low temperature | |
| CN110256698B (en) | Cellulose solvent and preparation method and application thereof | |
| CN106480128B (en) | Method for improving efficiency of cellulose in hydrolyzing rice straws by using lactic acid and guanidine hydrochloride | |
| CN105567764A (en) | Method for synthesizing long-chain chitosan ester under catalysis of lipase in ionic liquid reaction medium | |
| CN101974109B (en) | Method for preparing maleylation hemicellulose | |
| CN101787082A (en) | Method for removing thalli in process of producing curdlan | |
| WO2013085053A1 (en) | Method for producing aqueous cellulose solution and method for producing cellulose derivative | |
| CN102371078A (en) | Recovery method for ionic liquid solvent generated from homogeneous acylation reaction of cellulose | |
| CN102381947B (en) | Synthesis method of chiral 2,2 '- di-alkoxy-1, 1'-binaphthyl | |
| CN102558365A (en) | Method for preparing ionic liquid containing cellulose triacetate through adopting bagasse cellulose as raw material | |
| CN107200787B (en) | A kind of imidazoles alginate ionic liquid and its synthetic method | |
| Swatloski et al. | Ionic Liquids for the Dissolution and Regneration of Cellulose | |
| CN110128555B (en) | Method for preparing cellulose nanocrystals | |
| CN113480582A (en) | Green and cyclic comprehensive utilization method for agricultural and forestry solid wastes | |
| Muhammad et al. | Dissolution of Bamboo (Gigantochloa scortechinii) Using Ionic Liquids | |
| CN115926020B (en) | Acetylated hyaluronate and preparation method and application thereof | |
| CN1286856C (en) | Process for preparing poly saccuinimide crosslinking modified chitin material | |
| CN111057007B (en) | Functionalized ionic liquid based on dual-core structure, preparation method thereof and use method of functionalized ionic liquid for degrading lignocellulose |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |