CN102702391A - Method for oxidative degradation of chitosan by H2O2 (hydrogen peroxide) in aqueous solution of acidic ionic liquid - Google Patents

Method for oxidative degradation of chitosan by H2O2 (hydrogen peroxide) in aqueous solution of acidic ionic liquid Download PDF

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CN102702391A
CN102702391A CN2012102227792A CN201210222779A CN102702391A CN 102702391 A CN102702391 A CN 102702391A CN 2012102227792 A CN2012102227792 A CN 2012102227792A CN 201210222779 A CN201210222779 A CN 201210222779A CN 102702391 A CN102702391 A CN 102702391A
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chitosan
aqueous solution
ionic liquid
alkyl
ion liquid
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臧洪俊
李大庆
杨芳
吴长春
程博闻
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Tianjin Polytechnic University
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Tianjin Polytechnic University
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Abstract

The invention relates to a method for oxidative degradation of chitosan by H2O2 (hydrogen peroxide) in aqueous solution of acidic ionic liquid. The method comprises the steps of dissolving material chitosan into aqueous solution of acidic ionic liquid, slowly dripping a certain amount of hydrogen peroxide, carrying out heating reaction, adjusting the pH value of the degradation products to 8-9 by potassium hydroxide or sodium hydroxide solution, participating, washing and drying degradation products in vacuum with ethanol or acetone to obtain low-molecular-weight chitosan. The method disclosed by the invention has the characteristics of simple process, short reaction period and the like, and the ionic liquid can be repeatedly used for a plurality of times, so that the production cost is obviously reduced.

Description

H in the acidic ion liquid aqueous solution 2O 2The oxidative degradation chitosan
Summary
The present invention relates to a kind of in the acidic ion liquid aqueous solution hydrogen peroxide oxidation degrade chitosan.This method is dissolved in chitosan in the acidic ion liquid aqueous solution, slowly drips a certain amount of ydrogen peroxide 50, and reacting by heating is after reaction finishes.Degraded product is regulated the pH value to 8-9 with Pottasium Hydroxide or sodium hydroxide solution, and ethanol or acetone precipitation, washing, vacuum-drying obtain low-molecular weight chitoglycan.The present invention has characteristics such as technology is simple, reaction time is short, and ionic liquid can repeated multiple times use, and production cost is significantly descended.
Claims
1. the method for a degrade chitosan: it is characterized in that with the acidic ion liquid aqueous solution as solvent and catalyzer; Be heated to the chitosan that adds a certain amount of pulverizing after 30-140 ℃; After treating that chitosan dissolves fully, slowly dripping a certain amount of massfraction is 30%H 2O 2Reacted 2 minutes-30 hours; The chitosan aqueous solution of regulating above-mentioned cooling room temperature with 1mol/L NaOH adds certain amount of solvent simultaneously more chitosan is separated out to the pH to 8-10, use deionized water with above-mentioned chitosan of separating out wash to pH be about 7; Vacuum-drying obtains low-molecular weight chitoglycan.
2. according to H in the said acidic ion liquid aqueous solution of claim 1 2O 2Oxidative degradation chitosan method is characterized in that: described chitosan η=25-590cps, granularity is 80 orders, purity>=90%, moisture≤9%, ash≤1%.
3. acidic ion liquid aqueous solution edman degradation Edman according to claim 1 prepares the lower molecular weight chitose.It is characterized in that: said ionic liquid is for to have better dissolving power to chitosan or crust; The ionic compound that constitutes by zwitterion, wherein positively charged ion be alkyl imidazole, alkyl pyridine, alkyl indoles, alkyl thiazole, pyrrolidone, alkyl morpholine, quaternary ammonium cation or season phosphine type positively charged ion; Said ion liquid negatively charged ion is RSO 3 -, SO 4 -, HCO 2 -, CH 3CO 2 -, CF 3SO 3 -, PO 4 3-, PW 12O 40 3-, PMO 12O 40 3-, ClO 4 -
4. according to claim 1 or 2 described methods, its characteristic also is: the alkyl that said ion liquid positively charged ion contains can be H, (CH 2) nSO 3The alkyl of H or C1-C8 can be identical or different.Said ion liquid negatively charged ion is the polyprotonic acid acid ion HSO that contains ionizable proton 4 -, HPO 4 2-, H 2PO 4 -, HO 2CCO 2 -, H 2PW 12O 40 -, H 2PMO 12O 40 -
Advantage in the system.
The present invention also adopts the ionic liquid aqueous solution of thiazoles, pyridines and morpholine class to come as reaction system in addition, and this has widened choice of Solvent for the degraded of chitosan again.Ionic liquid aqueous solution can repeated multiple times, has reduced production cost, operates also simply relatively, and degradation time is short, is fit to industriallization.
Summary of the invention
Be to improve degradation of chitosan efficient, the object of the present invention is to provide a kind of easy and simple to handle, mild condition, eco-friendly novel method.
For realizing above-mentioned purpose, the technical scheme that the present invention adopts is:
A kind of method of degrade chitosan: it is characterized in that with the acidic ion liquid aqueous solution as solvent and catalyzer; Be heated to the raw materials of chitosan that adds a certain amount of pulverizing after 30-140 ℃; Wherein the concentration of ionic liquid in water is 2-12wt%, raw materials of chitosan and ion liquid mass ratio 2-10wt%.After treating that chitosan dissolves fully, slowly dripping a certain amount of massfraction is 30%H 2O 2, H wherein 2O 2The ratio of amount of substance and raw materials of chitosan unit amount of substance be R, the span of R is 1.5-6.Reacted 2 minutes-30 hours; The chitosan aqueous solution of regulating above-mentioned cooling room temperature with 1mol/L NaOH is to the pH to 8-10; Adding certain amount of solvent simultaneously separates out more chitosan; Use deionized water with above-mentioned chitosan of separating out wash to pH be about 7, vacuum-drying obtains low-molecular weight chitoglycan.
The ionic liquid that the present invention uses is for to have better dissolving power to chitosan or crust; The ionic compound that constitutes by zwitterion, wherein positively charged ion be alkyl imidazole, alkyl pyridine, alkyl indoles, alkyl thiazole, pyrrolidone, alkyl morpholine, quaternary ammonium cation or season phosphine type positively charged ion; Said ion liquid negatively charged ion is RSO 3 -, SO 4 -, HCO 2 -, CH 3CO 2 -, CF 3SO 3 -, PO 4 3-, PW 12O 40 3-, PMO 12O 40 3-, ClO 4 -
The ionic liquid that the present invention uses, its characteristic also is: the alkyl that said ion liquid positively charged ion contains can be H, (CH 2) nSO 3The alkyl of H or C1-C8 can be identical or different.Said ion liquid negatively charged ion is the polyprotonic acid acid ion HSO that contains ionizable proton 4 -, HPO 4 2-, H 2PO 4 -, HO 2CCO 2 -, H 2PW 12O 40 -, H 2PMO 12O 40 -
Among the present invention, the concentration of acidic ion liquid in water is 2-12wt%, raw materials of chitosan and ion liquid mass ratio 2-10wt% in reaction system.
Among the present invention, H in reaction system 2O 2The ratio of amount of substance and raw materials of chitosan unit amount of substance be R, the span of R is 1.5-6.
Among the present invention, the best degradation temperature of oil bath is 80-140 ℃, H in the reaction system 2O 2The ratio of amount of substance and raw materials of chitosan unit amount of substance be R, R is best, and value is 3, degradation time is 3-24 hour.
The present invention is in separating out the process of chitosan, and the chitosan aqueous solution that must regulate above-mentioned cooling room temperature with 1mol/L NaOH adds ethanol or acetone as precipitation agent to the pH to 8-10 then, filter, vacuum-drying.Then in effect:
(1) ionic liquid aqueous solution provided by the invention is a solvent, and it is volatile to have overcome conventional solvent, be difficult for to reclaim, seriously polluted, etching apparatus serious shortcoming, comparing with traditional organic solvent is a kind of relatively green solvent of environmental protection.
(2) to prepare the reaction system that low-molecular weight chitoglycan prepares in the process be homogeneous system (＞80 ℃) in the present invention, avoided H 2O 2The shortcoming that the oxidative degradation chitosan should exist in nonhomogeneous system.
(3) the used solvent of the present invention is that ionic liquid aqueous solution replaces pure ionic liquid in the past, and stable performance, can reuse, and expand ion liquid scope, reduces production costs, and pollutes for a short time, meets the theory of modern recycling economy.
Embodiment
Below be used to further specify the method that the present invention describes through the practical implementation instance, but be not intended that the invention be limited to these embodiment.
Embodiment 1
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 2% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is 14 * 10 3, yield 84%.
Embodiment 2
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is 6623, yield 73%.
Embodiment 3
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 6% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is 8592, yield 68%.
Embodiment 4
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 8% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is 6584, yield 61%.
Embodiment 5
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [HSO 4], 2ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 120 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is 7934, yield 59%.
Embodiment 6
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 10 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 5016, yield 50%.
Embodiment 7
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 110 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 3814, yield 51%.
Embodiment 8
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-pyridine hydrosulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3Hpy] [HSO 4], 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 9835, yield 74%.
Embodiment 9
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-morpholine hydrosulfate [C that 25ml contains massfraction 4% 3SO 3Hnhm] HSO 4, 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 11023, yield 76%.
Embodiment 10
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-indoxylsulfuric acid hydrogen salt, 0.53ml massfraction 30%H that 25ml contains massfraction 4% 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 13453, yield 81%.
Embodiment 11
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-indoxylsulfuric acid hydrogen salt, 0.53ml massfraction 30%H that 25ml contains massfraction 4% 2O 2Aqueous solution even, stopped reaction after 120 ℃ of oil bath lower magnetic forces stir 10 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 8987, yield 75%.
Embodiment 12
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-pyrroles's hydrosulfate, 0.53ml massfraction 30%H that 25ml contains massfraction 4% 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 10 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 9486, yield 78%.
Embodiment 13
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-pyrrolidone hydrosulfate [C that 25ml contains massfraction 4% 3SO 3Hnhp] HSO 4, 0.53ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 8743, yield 84%.
Embodiment 14
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazole bisulfate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [HSO 4], 2ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 2432, yield 60%.
Embodiment 15
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazoles hydrophosphate [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [H 2PO 4] aqueous solution evenly, 2ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 9513, yield 74%.
Embodiment 16
0.25g through 80 ℃ of dry chitosans (viscosity is 295cps) of crossing of 8 hours vacuum, is joined ionic liquid N-(4-sulfonic group) butyl-imidazoles phospho-wolframic acid hydrogen salt [(CH that 25ml contains massfraction 4% 2) 4SO 3HMIM] [H 2PW 12O 40] aqueous solution evenly, 2ml massfraction 30%H 2O 2Aqueous solution even, stopped reaction after 80 ℃ of oil bath lower magnetic forces stir 3 hours obtains evenly bright yellow solution, cool to room temperature has chitosan and separates out and add a certain amount of ethanol simultaneously more chitosan is separated out.Regulate the above-mentioned chitosan aqueous solution that is cooled to room temperature to the pH to 8-10 with 1mol/L NaOH, use then deionized water with above-mentioned chitosan of separating out wash to pH be about 7.80 ℃ of above-mentioned chitosan 24h of vacuum-drying measure the viscosity of degraded back chitosan with dark type viscometer under 25 ℃, and the molecular weight that calculates degraded back chitosan is about 5476, yield 82%.

Claims (9)

1. the method for a degrade chitosan: it is characterized in that with the acidic ion liquid aqueous solution as solvent and catalyzer; Be heated to the raw materials of chitosan that adds a certain amount of pulverizing after 30-140 ℃; Wherein the concentration of ionic liquid in water is 2-12wt%, raw materials of chitosan and ion liquid mass ratio 2-10wt%.After treating that chitosan dissolves fully, slowly dripping a certain amount of massfraction is 30%H 2O 2, H wherein 2O 2The ratio of amount of substance and raw materials of chitosan unit amount of substance be R, the span of R is 1.5-6.Reacted 2 minutes-30 hours; The chitosan aqueous solution of regulating above-mentioned cooling room temperature with 1mol/L NaOH is to the pH to 8-10; Adding certain amount of solvent simultaneously separates out more chitosan; Use deionized water with above-mentioned chitosan of separating out wash to pH be about 7, vacuum-drying obtains low-molecular weight chitoglycan.
2. according to H in the said acidic ion liquid aqueous solution of claim 1 2O 2Oxidative degradation chitosan method is characterized in that: described raw materials of chitosan η=25-590cps, granularity is 80 orders, purity>=90%, moisture≤9%, ash≤1%.
3. acidic ion liquid aqueous solution edman degradation Edman according to claim 1 prepares the lower molecular weight chitose.
It is characterized in that: said ionic liquid have better dissolving power to raw materials of chitosan or crust; The ionic compound that constitutes by zwitterion, wherein positively charged ion be alkyl imidazole, alkyl pyridine, alkyl indoles, alkyl thiazole, pyrrolidone, alkyl morpholine, quaternary ammonium cation or season phosphine type positively charged ion; Said ion liquid negatively charged ion is RSO 3 -, SO 4 -, HCO 2 -, CH 3CO 2 -, CF 3SO 3 -, PO 4 3-, PW 12O 40 3-, PMO 12O 40 3-, ClO 4 -
4. according to claim 1 or 2 described methods, its characteristic also is: the alkyl that said ion liquid positively charged ion contains can be H, (CH 2) nSO 3The alkyl of H or C1-C8 can be identical or different.Said ion liquid negatively charged ion is the polyprotonic acid acid ion HSO that contains ionizable proton 4 -, HPO 4 2-, H 2PO 4 -, HO 2CCO 2 -, H 2PW 12O 40 -, H 2PMO 12O 40 -
5. method according to claim 1 is characterized in that: the concentration of described ionic liquid in water is 2-12wt%.
6. according to the described method of claim 1, its characteristic also is: raw materials of chitosan and ion liquid mass ratio 2-10wt%.
7. according to the described method of claim 1, its characteristic also is: H 2O 2The ratio of amount of substance and raw materials of chitosan unit amount of substance be R, the span of R is 1.5-6.
8. the acidic ion liquid aqueous solution according to claim 1 prepares the low-molecular weight chitoglycan method, it is characterized in that: the best degradation temperature of described oil bath is 80-140 ℃, and R is best, and value is 3, and degradation time is 3-24 hour.
9. prepare the low-molecular weight chitoglycan method according to the said acidic ion liquid aqueous solution of claim 1; It is characterized in that: in separating out the process of chitosan; The chitosan aqueous solution that must regulate above-mentioned cooling room temperature with 1mol/L NaOH is to the pH to 8-10; Add ethanol or acetone then as precipitation agent, filter, vacuum-drying.
CN2012102227792A 2012-07-02 2012-07-02 Method for oxidative degradation of chitosan by H2O2 (hydrogen peroxide) in aqueous solution of acidic ionic liquid Pending CN102702391A (en)

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CN104072634A (en) * 2014-07-16 2014-10-01 中国科学院海洋研究所 Preparation method for chitin oligosaccharides
CN109627355A (en) * 2018-12-05 2019-04-16 华南理工大学 A kind of method that ionic liquid degradation chitosan prepares Water soluble oligo chitosan
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CN113321287A (en) * 2021-06-09 2021-08-31 昆明理工大学 Method for degrading antibiotics by hydrogen peroxide through ionic liquid aqueous phase transfer catalysis

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* Cited by examiner, † Cited by third party
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CN104072634A (en) * 2014-07-16 2014-10-01 中国科学院海洋研究所 Preparation method for chitin oligosaccharides
CN104072634B (en) * 2014-07-16 2016-10-05 中国科学院海洋研究所 A kind of chitin oligose preparing process
CN109627355A (en) * 2018-12-05 2019-04-16 华南理工大学 A kind of method that ionic liquid degradation chitosan prepares Water soluble oligo chitosan
CN111056665A (en) * 2019-10-11 2020-04-24 华南理工大学 Method for cooperatively treating organic matter sewage by using ionic liquid and hydrogen peroxide
CN111056665B (en) * 2019-10-11 2022-08-26 华南理工大学 Method for cooperatively treating organic matter sewage by using ionic liquid and hydrogen peroxide
CN113321287A (en) * 2021-06-09 2021-08-31 昆明理工大学 Method for degrading antibiotics by hydrogen peroxide through ionic liquid aqueous phase transfer catalysis

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Application publication date: 20121003