A kind of method of preparing CMC
Technical field
What the present invention relates to is a kind of method of preparing CMC, specifically a kind of carboxylic of preparing high viscosity and high substituted degreeThe method of methyl chitosan.
Background technology
Chitin is a kind of nonpoisonous and tasteless white or the translucent solid of canescence, in water, diluted acid, diluted alkaline and general havingIn machine solvent, be difficult to dissolve, but chitin is processed N-acetyl group through concentrated base and is sloughed that more than 55% just to become soluble chitin be shellGlycan, the chemical name of shitosan is β-(Isosorbide-5-Nitrae)-2-amino-2-deoxidation-β-D-Glucose. CMC is poly-to shellA kind of water-solubility chitosan derivative obtaining after sugar modification, it has antibiotic property, is a kind of polyampholyte, is making upThere is multiple application product, the aspect such as fresh-keeping, medical.
The method of producing CMC in prior art has a lot, and for example patent CN1431229A discloses one and had excellentThe preparation method of the CMC of good moisture absorption, performance of keeping humidity, and the CMC making in this way substitutes thoroughlyPhaneroplasm acid is for cosmetics and clinical medicine aspect, and its preparation method is to pass through taking shitosan as raw material after the abundant acetylation of acid anhydridesN-Acetylated Chitosans, then N-Acetylated Chitosans is made to required carboxymethyl with chloroacetate reaction in sodium hydroxide solutionShitosan, degree of substitution by carboxymethyl is 0.6-1.0. Can also be taking chitin as raw material, under uniform temperature at 40%~60%NaOHIn solution, soak 0.5~5h, then add while stirring monoxone, then at 0~70 DEG C of reaction 0.5~5h, the control of alkali acid mass ratioIn (1.2~1.6): 1, at 0-80 DEG C of insulation 5~36h, then with watery hydrochloric acid neutralization, separated product, with 75% ethanolic solution washing,Be drying to obtain CMC in 60 DEG C.
But have the following disadvantages in above-mentioned traditional handicraft: 1. the pH scope that the CMC that conventional method obtains dissolvesAll be more than or equal to 7, and at food, medicine, in the industries such as cosmetics, the pH area requirement dissolving for CMCThe CMC that traditional handicraft is produced is all being more than or equal to 5, in acid solution, also can dissolving, therefore cannot be answered completelyFor above-mentioned field; 2. traditional handicraft reaction temperature is high, causes chain rupture, causes molecular weight to decline to a great extent, and product viscosity is low.
Summary of the invention
The object of the invention is to overcome the problem of deficiency of the prior art and existence, provide a kind of high viscosity, high substituted degree andThe preparation method of water-soluble better CMC, so that it is adapted at food more, medicine, in the industries such as cosmeticsApplication.
For achieving the above object and other objects, the present invention is achieved by the following technical solutions:
A method of preparing CMC, comprises the following steps:
(1) deacetylation: chitin is added in alkaline aqueous solution and react 3~6h under stirring condition, and reaction temperature is50~80 DEG C, then at 0~15 DEG C, leave standstill, then stir 1~4h at 50~80 DEG C, last centrifugal dehydration obtains shitosanSodium salt;
(2) carboxylation reaction: under alkali condition, absolute ethyl alcohol and monoxone are added in shitosan sodium salt, at 40~70 DEG CLower stirring 12~36h, obtains CMC sodium salt after centrifugal dehydration; After CMC sodium salt water is dissolvedPH is adjusted to neutrality, then separates out with ethanol cyclic washing, after centrifugal drying, obtain CMC.
Preferably, reaction standing time at 0~15 DEG C of temperature is 20h at least in above-mentioned steps (1).
Preferably, the concentration of above-mentioned steps (1) the neutral and alkali aqueous solution is 10%~65%. More preferably, above-mentioned steps (1)The concentration of the neutral and alkali aqueous solution is 40%~65%.
The pH of described alkaline aqueous solution is greater than 7.0 the aqueous solution, can be selected from alkaline aqueous solution conventional in prior art,As sodium hydrate aqueous solution, potassium hydroxide aqueous solution.
Preferably, the quality of above-mentioned steps (1) the neutral and alkali aqueous solution is 5~20 times of chitin quality.
Preferably, in above-mentioned steps (1), chitin carries out deacetylation by the processing method that colds and heat succeed each other, and has reduced crustElement degree of deacetylation, the deacetylation of described shitosan sodium salt is 0.5~0.65.
Preferably, the quality of absolute ethyl alcohol is 2~5 times of shitosan sodium salt quality in above-mentioned steps (2);
Preferably, in above-mentioned steps (2), chloroacetic quality is 0.5~1 times of shitosan sodium salt quality.
The molecular weight of the CMC obtaining by middle said method of the present invention is 30~700,000. Preferably, said methodThe molecular weight of the CMC obtaining is 50~600,000.
The degree of substitution by carboxymethyl of the CMC of the acquisition in above-mentioned steps (2) is 1.1~1.5. Preferably, step (2)In the degree of substitution by carboxymethyl of CMC of acquisition be 1.15~1.3. The carboxylic first of the CMC that traditional handicraft obtainsBase substitution value is generally less than 1.0. Due to the high degree of substitution by carboxymethyl of CMC in the present invention, make its hydrophily, guarantorMoist and hygroscopicity significantly rises, the carboxymethyl chitosan that it is also produced far above traditional handicraft as the effect of cosmetic humectantSugar.
The pH scope of the dissolving of the CMC being obtained by said method of the present invention is 4.5~14.0. Preferably, the present inventionDescribed in CMC can be dissolved in pH be in 4.5~6.5 acid solution. Carboxymethyl with traditional handicraft acquisitionThe pH scope that shitosan dissolves is 7.0~14.0 to compare, and the pH scope that the CMC that the inventive method obtains dissolves moreWide, widen its application.
In traditional handicraft, deacetylation temperature is higher, and in step of the present invention (1), adopts the technique of stand at low temperature, makesNaOH condenses, and successfully by the molecular structure expansionization of chitin, has reduced the degree that is difficult to of the upper substitution reaction of 6C, therebyReduce the deacetylation of product; In addition, owing to reducing reaction temperature, avoided the high chain rupture causing of reaction temperature, thereby madeThe CMC that makes of technique of the present invention has high molecular weight and viscosity, the carboxylic first obtaining according to the inventive methodIts viscosity that base shitosan is made 1% the aqueous solution can reach 400cps, considerably beyond 50cps of the prior art.
The invention discloses a kind of method of CMC, the method, taking chitin as raw material, first, by chitin alkalization, makesCarry out deacetylation by the method for colding and heat succeed each other, produce shitosan sodium salt, then under alkali condition, carry out carboxylation reaction, obtainedThe CMC of water-soluble, high viscosity and high substituted degree. Overcome the deficiency of producing CMC in traditional handicraft,And technique is simple, be easy to control, be applicable to large-scale industrialization and produce.
Detailed description of the invention
Below embodiments of the invention are elaborated: the present embodiment is implemented under taking technical solution of the present invention as prerequisite,Provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
Embodiment 1
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 50% sodium hydrate aqueous solution that 40Kg chitin is added to 600Kg concentration,Under stirring condition, react 4h, reaction temperature is 75 DEG C, then at 10 DEG C, leaves standstill 24h, then at 75 DEG CStir 2h, last centrifugal dehydration obtains 150Kg shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 400Kg absolute ethyl alcohol and 80Kg monoxone are added to step (1)In the 150Kg shitosan sodium salt of middle acquisition, at 50 DEG C, stir 24h, centrifugal rear acquisition CMCSodium salt; After will CMC sodium salt water dissolving, pH is adjusted to neutrality, then analyses with ethanol cyclic washingGo out, after centrifugal drying, obtain CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.6; The degree of substitution by carboxymethyl of CMCBe 1.3; The viscosity of the CMC obtaining in the present embodiment being made to 1% the aqueous solution is 400cps, carboxymethylThe dissolving pH scope of shitosan is 4.5~14.0, within the scope of this pH without insoluble matter (insoluble matter amount≤0.01%), whenWhen pH=6.5,1% aqueous solution light transmittance reaches 98%. The CMC that the present embodiment obtains is adapted at food,Medicine, applies in the industries such as cosmetics.
Embodiment 2
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 65% sodium hydrate aqueous solution that 40Kg chitin is added to 500Kg concentration, is stirringMix under condition and react 3h, reaction temperature is 80 DEG C, then at 15 DEG C, leave standstill 30h, then stir 1h at 80 DEG C,Last centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 300Kg absolute ethyl alcohol and 150Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 40 DEG C, stir 24h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, obtains carboxylic after centrifugal dryingMethyl chitosan.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.65; The carboxymethyl of CMC replacesDegree is 1.5; The molecular weight of the CMC obtaining is 550,000, by the CMC obtaining in the present embodimentThe viscosity of making 1% the aqueous solution is 300cps, and it is 4.5~14.0 that this CMC dissolves pH scope, at thisThe CMC obtaining without insoluble matter (insoluble matter amount≤0.01%) the present embodiment within the scope of pH is adapted at food,Medicine, applies in the industries such as cosmetics.
Embodiment 3
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 40% sodium hydrate aqueous solution that 40Kg chitin is added to 600Kg concentration, is stirringMix under condition and react 6h, reaction temperature is 50 DEG C, then at 0 DEG C, leave standstill 20h, then stir 4h at 50 DEG C,Rear centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 500Kg absolute ethyl alcohol and 100Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 70 DEG C, stir 20h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, after centrifugal drying, is becomeProduct CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.5; The carboxymethyl of CMC replacesDegree is 1.3; The molecular weight of the CMC obtaining is 500,000, by the CMC obtaining in the present embodimentThe viscosity of making 1% the aqueous solution is 200cps; It is 4.5~14.0 that this CMC dissolves pH scope, at thisThe CMC obtaining without insoluble matter (insoluble matter amount≤0.01%) the present embodiment within the scope of pH is adapted at food,Medicine, applies in the industries such as cosmetics.
Embodiment 4
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 30% sodium hydrate aqueous solution that 40Kg chitin is added to 700Kg concentration, is stirringMix under condition and react 6h, reaction temperature is 65 DEG C, then at 10 DEG C, leave standstill 36h, then stir 3h at 60 DEG C,Last centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 450Kg absolute ethyl alcohol and 150Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 70 DEG C, stir 36h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, after centrifugal drying, is becomeProduct CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.6; The carboxymethyl of CMC replacesDegree is 1.5; The viscosity of the CMC obtaining in the present embodiment being made to 1% the aqueous solution is 350cps; ThisIt is 4.5~14.0 that CMC dissolves pH scope, within the scope of this pH without insoluble matter (insoluble matter amount≤0.01%);The CMC that the present embodiment obtains is adapted at food, and medicine, applies in the industries such as cosmetics.
Embodiment 5
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 20% sodium hydrate aqueous solution that 40Kg chitin is added to 800Kg concentration, is stirringMix under condition and react 4h, reaction temperature is 65 DEG C, then at 10 DEG C, leave standstill 36h, then stir 3h at 60 DEG C,Last centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 450Kg absolute ethyl alcohol and 120Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 60 DEG C, stir 36h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, after centrifugal drying, is becomeProduct CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.5; The carboxymethyl of CMC replacesDegree is 1.5; The viscosity of the CMC obtaining in the present embodiment being made to 1% the aqueous solution is 410cps; ThisIt is 4.5~14.0 that CMC dissolves pH scope, within the scope of this pH without insoluble matter (insoluble matter amount≤0.01%);The CMC that the present embodiment obtains is adapted at food, and medicine, applies in the industries such as cosmetics.
Embodiment 6
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 65% sodium hydrate aqueous solution that 40Kg chitin is added to 200Kg concentration, is stirringMix under condition and react 6h, reaction temperature is 60 DEG C, then at 5 DEG C, leave standstill 36h, then stir 3h at 60 DEG C,Rear centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 500Kg absolute ethyl alcohol and 150Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 50 DEG C, stir 36h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, after centrifugal drying, is becomeProduct CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.52; The carboxymethyl of CMC replacesDegree is 1.15; The viscosity of the CMC obtaining in the present embodiment being made to 1% the aqueous solution is 300cps; ThisIt is 4.5~14.0 that kind of CMC dissolves pH scope, within the scope of this pH without insoluble matter (insoluble matter amount≤0.01%); The CMC that the present embodiment obtains is adapted at food, and medicine, applies in the industries such as cosmetics.
Embodiment 7
The concrete technology step of preparing CMC in the present embodiment is as follows:
(1) deacetylation: it is in 50% sodium hydrate aqueous solution that 40Kg chitin is added to 200Kg concentration, is stirringMix under condition and react 6h, reaction temperature is 50 DEG C, then at 5 DEG C, leave standstill 24h, then stir 3h at 60 DEG C,Rear centrifugal dehydration obtains shitosan sodium salt;
(2) carboxylation reaction: under alkali condition, 300Kg absolute ethyl alcohol and 100Kg monoxone are added to step (1)In the shitosan sodium salt of middle acquisition, at 50 DEG C, stir 30h, centrifugal rear acquisition CMC sodium salt; By carboxylic firstBase shitosan sodium salt water is adjusted to neutrality by pH after dissolving, then separates out with ethanol cyclic washing, after centrifugal drying, is becomeProduct CMC.
In the present embodiment step (1), the deacetylation of shitosan sodium salt is 0.52; The carboxymethyl of CMC replacesDegree is 1.1; The viscosity of the CMC obtaining in the present embodiment being made to 1% the aqueous solution is 300cps; ThisIt is 4.5~14.0 that CMC dissolves pH scope, within the scope of this pH without insoluble matter (insoluble matter amount≤0.01%);The CMC that the present embodiment obtains is adapted at food, and medicine, applies in the industries such as cosmetics.