KR19990057607A - Chitosan Derivative Manufacturing Method - Google Patents

Abstract

In the synthesis of chitosan derivatives, the present invention relates to a method for preparing chitosan derivatives, comprising a pretreatment step of dispersing chitosan in an organic acid or inorganic acid solution before preparing chitosan in an organic dispersant, to prepare chitosan first. By efficient production of chitosan derivatives, the usability of chitosan can be increased, and the application range can be expanded due to the high efficiency of introducing functional groups.

Description

Chitosan Derivative Manufacturing Method

The present invention relates to a method for producing a chitosan derivative, and more particularly, before dispersing it in an organic dispersant, chitosan is dispersed in a suitable organic or inorganic salt solution to form a chitosan derivative in the form of a uniform chitosan, thereby providing a higher degree of substitution. Eggplant relates to a method for producing chitosan derivatives.

Chitosan derivatives have been used as a flocculant or dehydrating agent for wastewater treatment, but the advantages and properties of chitin and chitosan have been revealed, and reinforcing agents such as concrete compositions, additives in the paper or textile industry, and adsorbents (water or blood). In addition to the application of food and feed additives, membranes, films, fibers, coatings, cosmetics such as shampoos, hair sprays, toothpastes, and nail protectants, as well as biotechnology such as antimicrobial molds, enzyme separation, immobilization, etc. It is done in various ways.

In addition, commercially available chitosan is a polysaccharide composed of amino glucose units, which is based on N-acetylaminoglucose as a basic unit, and the starting material is chitin after alkaline saponification of N-acetyl group. The chemical or biological treatment of chitin to remove the acetyl group converts it to a free amino (-NH ₂ ) group. It is chitosan that the pyranose unit of glocosamine formed in this way is connected by a myriad of beta-1,4 bonds. Furthermore, chitosan can form free salts by reacting free amino groups (-NH ₂ ) with free bases to easily react with acids.

Commercially used chitosans mainly have 60-90% N-acetyl groups and mean dgree of polymerization generally ranges from 500 to 10,000, while natural chitin always has a value of at least 5,000.

Exemplary chitosan derivatives have shown various possibilities for the carboxymethylation of chitosan in the presence of alkali in "Carbohydrate Polymers 8 (1988), p 1-21), Int. J. Biol. Macromol. 10 (1988), p 124-125, J. Chem. Soc. Chem, Comm. (1980), pp. 1153-1154, J. App. Polymer Science 31 (1986), p 1951-1954, Macromol. Chem. 188 (1987), p1659-1664, et al. Describe the preparation of chitosan derivatives. In addition, European Patents EP-A 0,224,045 and EP-A 0,277,322 propose methods for producing chitosan derivatives such as N-hydroxymethylchitosan, N-hydroxypropylchitosan and N-hydroxypropyletherchitosan. A 0,115,574, DE-A 3,502,833 provide a method for preparing an ammonium group-introduced chidosan in water or a water-soluble organic solvent. Japanese Patent JP-A 61-60701 discloses a chitosan and a quaternary ammonium alkyl halogen component, glycidyl trialkylammonium. A method for preparing chitosan derivatives by reacting a halogen component with an alkylene oxide is proposed.

Chitosan derivatives presented in the above papers and patents are prepared by preparing a derivative from the preparation of a homogeneous chitosan, or by directly reacting chitosan using an appropriate reaction agent after dispersing an organic solvent of chitosan, or before forming a chitosan. The derivatives are prepared in water or an aqueous organic solvent through alkali treatment or by dispersing a solution of a suitable concentration (mainly 1% substrate concentration) in an aqueous solution or an alcohol solution and then adding an acid. However, these methods react due to the high viscosity of chitosan itself, or because they are reacted in a very dilute state, or because they are generally heterogeneous, the reaction efficiency is lowered and the yield of the actual target product is low. In particular, the rapid decomposition of the polymer chain by alkali treatment This causes a disadvantage in that the complexity and efficiency of the process during the separation / purification process is reduced.

In addition, in relation to the substitution reaction of the polymer, the substitution reaction of the general polymer is not uniform. Particularly, in the case of cellulose or starch, the substitution reaction is performed under uneven conditions, and the chemical substitution depends on the introduction site of the polymer chain. Exposure of the introduction site is an important factor in preparing chitosan derivatives, and is an important factor in inducing the reaction system to a uniform reaction system. In general, in order to achieve a uniform reaction system, a process of accommodating chitosan, which is a reaction target, is involved. To this end, chitosan is converted into a salt form and reacted, or chitosan is cut to a low molecular level, for example, an oligosaccharide level to give water solubility. The reaction is then performed. However, in the latter case, it takes a lot of time for the low-molecularization process, which is the process of accommodating chitosan polymer, and the problem of increasing the separation and purification time proportionally.

An object of the present invention is to solve the conventional problems as described above, in order to improve the factor of lowering the reaction efficiency, to minimize the loss of the product to prepare a chitoate by the addition of a suitable dispersing agent, a uniform reaction system To provide a method for producing a high efficiency chitosan derivative.

That is, in the synthesis of chitosan derivatives, the present invention relates to a method for producing chitosan derivatives, comprising a pretreatment process of preparing chitosan by dispersing it in an organic salt or an inorganic salt solution before the chitosan is dispersed in an organic dispersant. will be.

Hereinafter, the present invention will be described in detail.

In general, chitosan is prepared by adding an acid component to chitosan. If the starting material chitosan is a polymer, for example, molecular weight 2 × 10 ⁶ or more, or 1 × 10 ⁶ , water solubility is given after the reaction, so that the whole seems to be in the form of a salt, but the actual polymer chain is highly Because of their agglomerated form, even in the presence of a small amount of acid components, only a portion of the surface of the polymer is often in the form of a salt. As a result, only a part of the surface of the polymer may be homogeneous in the process of imparting a desired functional group, and the overall reaction efficiency is lowered.

In the present invention, chitosan can be prepared by minimizing the aggregation of polymer chains by blocking hydrophobicity in the chitosan molecule by adding an appropriate amount of an inorganic salt or an organic salt.

The present invention mainly consists of an aqueous solution, in particular an aqueous solution in which an inorganic salt is present, wherein the salt is preferably used in an amount sufficient so that the chitosan salt does not dissolve in the solution, and the amount of use depends on the type of salt used. . The content of the inorganic salt or organic salt to be added is preferably 5 to 20% by weight. Preferred types of salts include chlorides, nitrates, sulfites or acetates having excellent solubility in water, and alkali metal salts or ammonium metal salts are used. As the metal salt, sodium chloride, sodium sulfate, ammonium chloride, potassium chloride, ammonium sulfate, or sodium acetate is used.

After pretreatment of chitosan with inorganic or organic salts, water solubility is given to chitosan by adjusting the pH with acidic and alkaline solutions.

The chitosan salt thus prepared is mixed with the organic dispersant, and the organic dispersant used is an organic component with an organic component ratio of 2: 3 relative to the amount of water. Preferred organic dispersants are selected from the group consisting of alcohols such as ethanol and methanol, ethers such as dioxane, dimethyl glycol and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, and aromatic compounds such as toluene or hydrocarbons. do.

The amount of chitosan added for the preparation of the chitosan derivative of the present invention is 0.07 to 0.4% by weight relative to the dispersant, preferably 0.09 to 0.3% by weight.

In addition, the degree of deacetylation of chitosan is 40 to 96%, the polymerization degree is 100 to 10,000, preferably 1,000 to 7,000. If the degree of polymerization is less than 1,000, the amount of free amine is increased to increase the amount of added acid component, so that hydrolysis by a large amount of acid component may occur rapidly. The particle size of the chitosan is less than 1mm, preferably 0.04 to 0.3mm, when the particle size exceeds 1mm, the reaction efficiency may be lowered, if less than 0.04mm it is disadvantageous to the input and manufacturing.

The salt preparation reaction for the initial derivative synthesis is generally temperature dependent and is carried out at 50 to 100 ° C., preferably at 60 to 90 ° C. for 5 to 60 minutes, preferably at 10 to 60 conditions. If the temperature is less than 50 ℃ the reaction time is too long uneconomical, if it exceeds 90 ℃ there is a fear that the pyrolysis process occurs. In addition, if the reaction time is less than 10 minutes, the unreacted ratio is high, and the proper introduction of functional groups is not achieved. If the reaction time is over 60 minutes, the hydrolysis reaction with acid occurs, and the molecular chain is rapidly broken, which leads to many separation / purification. It is uneconomical with a heavy emphasis

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited by the following examples.

Example 1

10 g of chitosan having a degree of polymerization of 8,000, a degree of deacetylation of 60% and 0.01 mm or less was dispersed in 100 g of a 10% sodium chloride solution, 4.37 g of 37% hydrochloric acid was added to adjust the pH to 2.7, and stirred at 60 ° C. for 45 minutes. After cooling the stirred solution to 25 ° C., 4.35 g of 50% caustic soda was added to adjust the pH to 10.0, followed by filtration to prepare a chitosan salt having a water content of 80%. Thus prepared 263 g of chitoate and 260 g of methanol were mixed, stirred for 10 minutes, and 38 g of monochloroacetic acid was added thereto, followed by reaction at 80 ° C. for 6 hours under a nitrogen atmosphere to prepare N-carboxymethyl chitosan. The amino group substitution degree of N-carboxymethylchitosan obtained at this time was 0.30.

Example 2

10 g of chitosan having a degree of polymerization of 8,000, a degree of deacetylation of 60% and a particle size of 0.01 mm or less was dispersed in 80 g of 50% methanol, 4.37 g of 37% hydrochloric acid was added to adjust the pH to 2.7, followed by stirring at 60 ° C. for 60 minutes. After cooling the stirred solution to 25 ° C., 4.35 g of 50% caustic soda was added to adjust the pH to 9.0 level, followed by filtration and vacuum drying. 50 g of dried chitoate and 80 g of 50% methanol were mixed and stirred for 10 minutes. After 38 g of chloroacetic acid was added, the mixture was reacted at 80 ° C. for 6 hours under a nitrogen atmosphere to prepare N-carboxymethylchitosan. The amino group substitution degree of N-carboxymethyl chitosan obtained at this time was 0.34.

Example 3

10 g of chitosan having a degree of polymerization of 8,000, a degree of deacetylation of 60% and a particle size of 0.01 mm or less was dispersed in 100 g of a 10% sodium chloride solution, 4.37 g of 37% hydrochloric acid was added to adjust the pH to 2.7, followed by stirring at 60 ° C. for 45 minutes. The stirred solution was cooled to 25 ° C., and then added to 4.35 g of 50% caustic soda, adjusted to pH 10.0, and filtered to prepare a chitosan salt having an 80% water content. Thus prepared 156 g of chitoate and 260 g of methanol were mixed and stirred for 10 minutes, and then 85 g of methyl iodine was added and reacted at 80 ° C. for 5 hours under a nitrogen atmosphere to prepare N-trimethyl chitosan. The amino group substitution degree of N-trimethylchitosan obtained at this time was 0.33.

Comparative Example 1

In Example 1, 10 g of chitosan having a polymerization degree of 8,000, a deacetylation degree of 60%, and a particle size of 0.01 mm or less was mixed with 250 g of water for 10 minutes without chitosan preparation, and then 100 g of monochloroacetic acid was added thereto under a nitrogen atmosphere. The reaction was carried out at 80 ° C. for 26 hours to prepare N-carboxymethylchitosan. The amino group substitution degree of N-carboxymethylchitosan obtained at this time was 0.27.

Comparative Example 2

In Example 2, a mixture of 8,000 degree of polymerization, 60% deacetylation degree, chitosan having a particle size of 0.01 mm or less, 250 g of water, and 100 g of methanol was mixed for 10 minutes without chitosan, and then 100 g of monochloroacetic acid was added thereto. N-carboxymethylchitosan was prepared by reaction at 80 ° C. for 26 hours under a nitrogen atmosphere. The amino group substitution degree of N-carboxymethyl chitosan obtained at this time was 0.22.

Comparative Example 3

In Example 3, a mixture of 8,000 degree of polymerization, 60% deacetylation degree, 10 g of chitosan having a particle size of 0.01 mm or less, 250 g of water, and 100 g of methanol was mixed for 10 minutes without chitosan, and then 100 g of methyl iodine was added, followed by nitrogen. The reaction was carried out at 80 ° C. for 26 hours in an atmosphere to prepare N-trimethylchitosan. The amino group substitution degree of N-trimethylchitosan obtained at this time was 0.21.

As described above, the usability of chitosan can be increased by the efficient production of chitosan derivatives as in the present invention, and the application range can be expanded due to the high efficiency of functional group introduction.

Claims (4)

In the synthesis of chitosan derivatives, a method for producing chitosan derivatives, comprising a pretreatment step of dispersing chitosan in an inorganic salt or an organic salt solution to prepare chitosan before dispersing the chitosan in an organic dispersant. The salt of claim 1, wherein the salt type of the inorganic salt or organic salt solution is selected from the group consisting of chlorides, nitrates, sulfites, acetates, alkali metal salts, and ammonium metal salts. Method for producing a chitosan derivative, characterized in that selected from the group consisting of sodium sulfate, ammonium chloride, potassium chloride, ammonium sulfate, sodium acetate. The method of claim 1, wherein the organic dispersant is selected from the group consisting of aromatic compounds such as ethanol, methanol, dioxane, dimethyl glycol, tetrahydrofuran, acetone, methyl ethyl ketone, toluene, hydrocarbons, organic A method of producing a chitosan derivative, wherein the component ratio is 2: 3. The method of claim 1, wherein the chitosan has a deacetylation degree of 40 to 96% by weight and a polymerization degree of 100 to 10,000, using 0.07 to 0.4% by weight relative to the dispersant.