KR19980072168A - Process for preparing colorless transparent high viscosity 6-o-carboxymethyl-chitin solution and white 6-o-carboxymethyl-chitin powder - Google Patents

Abstract

The present invention relates to a method for preparing a colorless transparent high viscosity 6-O-carboxymethyl-chitin solution and white 6-O-carboxymethyl-chitin powder, and more particularly, to a method for producing high purity high molecular weight powder chitin and It relates to a method for producing a colorless transparent high viscosity 6-O-carboxymethyl-chitin having a degree of substitution of only 0.7-1.0 carbon atoms in chitin.

Description

Process for preparing colorless transparent high viscosity 6-o-carboxymethyl-chitin solution and white 6-o-carboxymethyl-chitin powder

The present invention relates to a method for preparing a colorless transparent high viscosity 6-O (alphabet upper case; same as below) -carboxymethyl-chitin solution and white 6-O-carboxymethyl-chitin powder, and more particularly, high purity high molecular weight powder. It relates to a method for preparing chitin and a method for preparing a colorless transparent high viscosity 6-O-carboxymethyl-chitin solution having a degree of substitution of 0.7 to 1.0 only in the hydroxyl group of carbon 6 of the chitin.

Many kinds of wastes that humans dispose of are beyond our limit of purification ability and threaten our survival. Among them, many synthetic polymer materials do not decompose in the natural environment and accumulate new serious environmental problems. It is causing. Recently, the landfill of these wastes has also reached its limit, and due to the dioxin problem generated during incineration, the use of existing synthetic polymers is increasingly restricted worldwide, and new environmentally friendly materials are urgently needed as alternative materials. . Therefore, the conversion of waste to useful resources needs to be preceded by the times.

The shells of crabs and shrimps, which are discarded as wastes, contain a lot of chitin and are very friendly to the natural environment, so they are cutting-edge materials for the ecological environment as well as the human living environment.

Crab and shrimp shells are organic waste produced in large quantities from the seafood processing industry and consist of chitin, one of natural polymers. Chitin is a major component of cuttlefish bones and can be extracted from crab shells.

This chitin, a raw material for chitosan production, is a polysaccharide (poly-β-1,4-N-acetyl-D-glucosamine) to which N-acetyl-D-glucosamine is bound to β- (1,4). This high, biocompatible natural polymer material that does not cause toxicity in vivo has a wide range of applications.

However, since chitin has a strong hydrogen bond in intermolecular molecules, it is insoluble in a general organic solvent and thus is difficult to be molded. In order to mold the chitin, dissolving the chitin should be preceded. However, since the solvent for dissolving the chitin is a strongly acidic solvent, it is impossible to maintain the molecular weight of the chitin as it is due to a decrease in molecular weight upon dissolution.

The present inventors have solved the above problems by dissolving chitin in calcium chloride-methanol solution to produce a colorless transparent high viscosity 6-O-carboxymethyl-chitin solution and white 6-O-carboxymethyl-chitin powder to the present invention. .

The method for preparing a colorless transparent high viscosity 6-O-carboxymethyl-chitin solution and white 6-O-carboxymethyl-chitin powder according to the present invention consists of the following steps.

1) Decalcifying a certain amount of crab shell with a dilute aqueous solution, washing until pH becomes neutral, deproteinizing with a dilute alkaline solution, and washing until pH becomes neutral

2) completely removing the pigment by irradiation with ultraviolet rays, vacuum drying and pulverizing with 20 to 200 mesh to prepare high purity high molecular weight chitin powder

3) dissolving the powder chitin in a calcium chloride-methanol solution and reprecipitating it in 2 to 10 times the amount of deionized water of the solution

4) replacing the precipitate with anhydrous ethanol while filtering with a vacuum filter, and slowly adding 4-10 times the weight of the chitin in the solid phase to granular NaOH at 4 ° C. or lower to produce an alkali chitin substituted with a hydroxyl group in the hydroxyl group.

5) A certain amount of anhydrous ethanol / anhydrous methanol is slowly added to the solution of 5-20 times mole of monochloroacetic acid of chitin in the mixed solution (1/1, V / V) at 4 ° C or lower, and 4 ° C or lower 6-O-carboxymethylated by stirring for 3 to 24 hours at 1000 to 2000 RPM while maintaining

6) preparing a 6-O-carboxymethyl-chitin solution by dialysis of the reactants using a dialysis membrane to concentrate the concentration of 0.5% to 7%.

7) Concentrating the solution to a concentration of 1% to 50% or more and freeze-drying to prepare 40 to 200 mesh of 6-O-carboxymethyl-chitin powder.

This chitin powder can be completely dissolved in water and a colorless transparent high viscosity solution having a viscosity of 50 to 1500 cps can be obtained depending on the kind of chitin which is a starting material.

In the above, 0.01% NaBH ₄ of the chitin weight is added during the deproteinization.

In addition, KMnO ₄ , EDTA and hydrochloric acid may be used instead of ultraviolet rays in the depigmentation process.

Example 1

The crab shell was decalcified with a dilute aqueous solution, washed until the pH became neutral, deproteinized with a dilute alkaline solution, and washed until the pH became neutral.

In the de-pigmentation process, the mixture was oxidized with KMnO ₄ solution and then reduced with EDTA and hydrochloric acid to completely remove the pigment, followed by vacuum drying and pulverization with 20 to 200 mesh to prepare high purity high molecular weight chitin powder.

The powder chitin was dissolved in calcium chloride-methanol solution and reprecipitated in 2 to 10 times deionized water of this solution.

After replacing the precipitate with anhydrous ethanol while filtering with a reduced pressure filter, granular NaOH was added slowly to 4-10 times the weight of the chitin as a solid at 4 ° C. or lower to prepare an alkali chitin substituted with a Na group in the hydroxyl group.

A certain amount of anhydrous ethanol / anhydrous methanol was slowly added to a solution of 5-20 times molar monochloroacetic acid of chitin in a mixed solution (1/1, V / V) at 4 ° C or lower, and kept at 4 ° C or lower. 6-O-carboxymethylated by stirring at 1000-2000 RPM for 3 to 24 hours.

The reactant was dialyzed with the dialysis membrane to concentrate the unreacted solution at a concentration of 0.5% to 7% to prepare a 6-O-carboxymethyl-chitin solution.

The solution was concentrated to a concentration of at least 1% to 50% and lyophilized to prepare 40-200 mesh of 6-O-carboxymethyl-chitin powder.

This chitin powder was dissolved completely in water to obtain a colorless transparent high viscosity solution.

According to the present invention, a colorless transparent high viscosity 6-O-carboxymethyl-chitin solution and white 6-O-carboxymethyl-chitin powder can be prepared.

Claims (4)

1) Decalcifying a certain amount of crab shell with a dilute aqueous solution, washing until pH becomes neutral, deproteinizing with a dilute alkaline solution, and washing until pH becomes neutral 2) completely removing the pigment by irradiation with ultraviolet rays, vacuum drying and pulverizing with 20 to 200 mesh to prepare high purity high molecular weight chitin powder 3) dissolving the powder chitin in a calcium chloride-methanol solution and reprecipitating it in 2 to 10 times the amount of deionized water of the solution 4) replacing the precipitate with anhydrous ethanol while filtering with a vacuum filter, and slowly adding 4-10 times the weight of the chitin in the solid phase to granular NaOH at 4 ° C. or lower to produce an alkali chitin substituted with a hydroxyl group in the hydroxyl group. 5) A certain amount of anhydrous ethanol / anhydrous methanol is slowly added to the solution of 5-20 times mole of monochloroacetic acid of chitin in the mixed solution (1/1, V / V) at 4 ° C or lower, and 4 ° C or lower 6-O-carboxymethylated by stirring for 3 to 24 hours at 1000 to 2000 RPM while maintaining 6) A colorless transparent high viscosity 6-O-carboxymethyl-chitin solution consisting of dialysis of the reactants using a dialysis membrane to concentrate the concentration of 0.5% to 7% to prepare a 6-O-carboxymethyl-chitin solution. Manufacturing method. The method of claim 1, wherein the addition of NaBH ₄ in 0.01% of the weight of chitin during the de-protein treated. The method of claim 1 wherein KMnO ₄ , EDTA and hydrochloric acid are used in place of ultraviolet light in the depigmentation process. The method of claim 1 is concentrated to a concentration of 1% to 50% or more and lyophilized to prepare 40 to 200 mesh of 6-O-carboxymethyl-chitin powder.