KR100216301B1 - Process for the manufacture of chitosan of which deacetylation ratio is 75-100 - Google Patents

Abstract

[Name] manufacturing method of chitosan with deacetylation degree of 75-100%

[Problem] In the conventional method for producing chitosan, there was a problem that the concentration of sodium hydroxide was high, the reaction time was long, the reaction temperature was high, but the deacetylation degree was not relatively high, which was not economical and was an obstacle to mass production. However, it was difficult to expect the expansion of the application range.

Try to resolve this.

[Solution] Take the back part of the shell, pulverize and powder it, and then immerse it in pharmacopeia 2N hydrochloric acid solution for 12-16 hours to remove calcium and ash, wash with distilled water until neutral and dry, and then dry Pharmacopoeia of the sample at 100 ° C. Deacetylation of the chitin powder obtained by immersing in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washing and drying in the sodium hydroxide (concentration 40-50% W / V) solution between 110-130 ° C After the reaction, the solution was washed several times, twice or three times with distilled water, and then dissolved in an aqueous acetic acid solution (concentration 2% V / V) to prepare an aqueous chitosan solution. Solution to a method of preparing chitosan having a deacetylation degree of about 75-100% by making a fibrous phase in 1N aqueous sodium hydroxide solution or by performing a deacetylation reaction for 1-2 hours.

Description

Method for preparing chitosan with deacetylation degree of 75-l00%

FIG. 1 is a graph of chitosan deacetylation with purity greater than 75% and less than 85%.

FIG. 2 is a graph of chitosan deacetylation with purity greater than 85% and less than 90%.

3 is a graph of chitosan deacetylation with purity greater than 90% and less than 95%.

4 is a graph of chitosan deacetylation at 100% purity.

5 shows Infrared Spectra at purity greater than 75% and less than 85%.

6 shows Infrared Spectra at purity greater than 85% and less than 90%.

7 shows Infrared Spectra at purity greater than 90% and less than 95%.

8 shows Infrared Spectra at 100% purity.

The present invention relates to a method for preparing chitosan having a deacetylation degree of 75-100%. By the 1970s, the world was devoted to the problem of depletion of oil and its recycling, and chitin was noted here.

Chitin is reported to be $ 100 billion annually in biosynthesis of polysaccharides, which are widely distributed in nature. This is close to the amount of cellulose produced, which is the second most abundant organic matter after cellulose on earth, but most of it is an extremely low-availability biomass jarn that is discarded.

As such, although chitin is present in nature in large quantities, the study on its use is being delayed, which is the biggest cause of the fact that chitin is insoluble and does not dissolve in a solvent. (1-4)

However, it has recently been spotlighted as a natural resource, and its industrial use is attracting attention because it is similar in structure to cellulose (5-6), and active research is being conducted in various fields. The specific function and activity of chitin and chitosan Attention is gaining attention as a functional polymer material and biodegradable material due to its wide applicability in various fields. (7-8)

However, it is conventionally difficult to express the complicated structure which is a characteristic of polysaccharide by chemical formula.

Therefore, in order to be able to control or effectively use many functional groups by the black formula, chitin should be recognized as a unique polymer material different from synthetic polymers or other natural polymers.

Chitin has the potential to undergo regioselective and efficient chemical formula due to the high reactivity of amino groups, and is thought to be superior to cellulose in terms of availability. (4, 9)

Chitosan is obtained by subjecting chitin to deacetylation in concentrated sodium hydroxide solution. In addition, chitosan can obtain different deacetylation substances according to reaction temperature, reaction time, and sodium hydroxide concentration during deacetylation (10). Since chitosan is relatively low in toxicity and biodegradable, research in medicine Began to grow rapidly (11-23).

Chitosan is a basic polysaccharide that has been shown to antagonize the stomach and inhibit ulcers in animal experiments. In addition, in animal experiments, chitin and chitosan have been found to have important pharmacological effects of lowering the levels of cholesterol and triglycerides in serum and liver, and many experimental data have been published.

Chitosan acts to selectively aggregate leukemia L1210 cells and does not affect normal erythrocytes and bone marrow cells.

Micropurge activating ability is high in the degree of deacetylation of 0.70, suggesting the possibility of partially deacetylated chitin as an immunostimulating activator. (24)

The physiological activity of the oligosaccharides of chitin and chitosan is also interesting.

Examination of antitumor and antimicrobial results showed that hexamer showed particularly high activity.

The antibacterial, antifungal and antiviral properties of these oligomers have also been reported. In addition, the addition of chitosan also has the effect of improving the food preservation, so the use as a new food preservative has been discussed.

Since the function of chitosan varies greatly depending on the difference in its molecular weight and aceylation degree, it is very important to set and control conditions such as alkali concentration, reaction temperature and reaction time used in the reaction.

In particular, as the range of use expands, the need for chitosan having a high degree of deacetylation is increasing. Therefore, a new method for obtaining chitosan having a high degree of deacetylation is required.

Chitosan, which is currently commercially available, is deacetylated at about 70-80% by reaction at an alkali concentration of 40-60% at a reaction temperature of 100-180 degrees Celsius for 2-4 hours.

In the conventional method, there is a problem that the concentration of sodium hydroxide is high, the reaction time is long, and the reaction temperature is high, but the deacetylation degree is not relatively high, which is not economical and is an obstacle to mass production. There was a hard disadvantage.

Accordingly, the present invention provides a method for producing high quality chitosan having a deacetylation degree of 75-100% in a short reaction time on a low reaction temperature and low sodium hydroxide.

Looking at the detailed features and uses of chitosan,

▶ Function and use of grade 75-85% chitosan

Cosmetic field

This field has been studied for the longest time in the application of chitin and chitosan and the available properties are revealed.

The main reason why the use of chitosan as a cosmetics product has been advanced is in hair adsorption. Chitosan exhibits functions such as moisture retention, antistatic properties, and film formation after being adsorbed on the hair.

(1) Application of carboxymethyl chitin to cosmetics

Carboxymethyl chitin can be dissolved in water at any pH, unlike chitosan. It is also reported to have high moisturizing properties and antistatic effect on hair. (10)

[Wastewater treatment field]

(1) flocculant

The chief use of chitosan has been flocculants for wastewater.

The free amino groups of chitosan have been used mainly as cationic natural polymer flocculants because they are charged with cations in aqueous solutions at pH 7 or below.

It has been mainly used for resource recovery in waste water by taking advantage of excellent dehydration, natural degradability and pollution-free.

Recovering proteins in food plant wastewater and recycling them to feed or compost, or recovering livestock wastewater floats and developing them as special horticultural compost will bring about soil recovery, such as improvement of soil ecosystem due to the control of chitosan filamentous fungi. It will come to the spotlight for the excellent soil improvement compost coming. (25)

(2) heavy metal ion adsorption

Chitin and chitosan have strong adsorption to heavy metals.

After filling the column with various forms (bead, powder, etc.) and passing heavy metal contaminated water, a considerable amount of heavy metal can be adsorbed and removed.

In the case of a single heavy metal, the removal efficiency due to pH change is removed by more than 85% at pH 2, and mixed heavy metal adsorption is removed by pH 2 or more by 70%.

(3) Dye Wastewater Purifier

Chitosan has a strong adsorption to dyes.

This may help to clean up the dyeing plant wastewater.

Grade 85-90% Chitosan Functions and Uses

[Agriculture]

Several experiments have shown that low molecules and oligosaccharides of chitin and chitosan have significant control over pathogens and pests.

(1) soil improver

The use of crabs and shrimp for composting has strengthened the soil's intellect, which has been recognized by farmers' experience.

Chitin and chitosan have been found to inhibit filamentous fungi, which are harmful to plants, among the microorganisms in the soil, and to grow actinomycetes beneficial to plants.

Of course, mixing crab or shrimp shells with compost will have a beneficial effect on crop growth. In particular, the use of chitin or chitosan for the development of special wintry crops and special crop composts will be of great value.

It is also desirable to apply to cropland where crop rotation is inevitable. It is also advisable to test spray these oligosaccharides of chitin or chitosan on golf courses or other crop plantations that pollute the environment with toxic pesticides.

(2) Plant pest control agent

It is also advisable to apply hydrolyzate of chitin or chitosan to control pests and pathogens that invade plants.

It is known that these oligosaccharides prevent the growth of these pests and pathogens by blocking the transcription of DNA from the DNA, which is a gene transfer mechanism of a pest or pathogen.

By using these properties, the development of chitin-free pesticides (natural enemies) that control pests and pathogens by genetic engineering techniques is expected to occur soon.

(3) sustained-release pesticides

In order to prevent the pesticides sprayed on the crops from being easily lost by rain and wind, and to apply the pesticides to the polymer chitosan to liquefy them for long-lasting effects on the crops, spraying them after liquefaction and anti-pathogenicity of chitosan Will appear large.

R & D in this area may also be of considerable interest.

(4) Elicitor

Seeds of wheat or legumes coated with chitosan seed so that the stem is much thicker and yields are greatly increased.

It may be tested in bean sprout cultivation.

(5) poultry

When chitin or chitosan is added to the feed of laying hens, the laying rate increases, and when applied to silkworms or mulberry leaves, the growth of silkworms is accelerated.

▶ Function and use of grade 90-95% chitosan

[Textile field (26-27)]

Chitosan's textile-related applications include hygiene processing such as antibacterial and deodorization, as well as the possibility of application as a material that imposes new functionality such as antistatic, shrinkage, wrinkle prevention, and dyeing. It can be used as malignant wastewater treatment cloth generated in related fields, filter cloth used for water purification treatment, fabric touch and handle improvement processing agent.

Since chitosan is attached between fibers and yarns to increase shear and bending stiffness, the toughness of fabric inertia increases, suggesting the possibility of using it as a desirable garment material for high temperature and high summer.

Also, due to the surface characteristics of the treated fabric, the friction coefficient tends to decrease with increasing the concentration of chitosan.

[Food sector (28-30)]

(1) cholesterol lowering agents

As the diet has become more westernized recently, LDL (harmful form) is higher than HDL (harmful form). It works.

(2) Cleaners and softeners for beverages, juices, alcoholic beverages

Water-soluble chitosan is added to remove suspended soils in drinks, juices and alcohol.

At the same time, it not only inhibits bacterial growth but also helps physiological activity.

(3) Desorbent of thick metal in food

Chitosan is a useful adsorbent when metals, especially polluted heavy metals, are incorporated into foods.

(4) food preservatives

It can be used as a preservative to prevent the decay of food by using antibacterial properties of low molecular weight of chitin and chitosan and oligosaccharides.

Compared to the existing harmful toxic chemical preservatives, it can be evaluated as a groundbreaking preservative and at the same time, it is effective in preventing the growth of mold or bacteria in food.

(5) Sustained release preparation

When used as a carrier by combining the nutrients or aroma components with chitosan molecules, it is possible to properly maintain the supply of nutrients in the body and also to keep the aroma components in foods for a long time and gradually release them.

(6) antacids

Acidic substances in foods can be neutralized with many amino groups of chitosan.

In particular, when the organic acid is produced in fermented foods, the addition of chitosan has a neutralizing effect and can control the organic acid fermentation microorganisms, which has the effect of yield.

In Korea's dietary culture, where fermented foods such as kimchi are used in large amounts for corrosion, it is worth paying attention to this research.

(7) Coloring and Decolorizing Aids

The strong pigment adsorption of chitin and chitosan will make it very useful for coloring foods or removing unpleasant pigments from foods.

(8) Special ingredient remover

It can be used to adsorb and remove special components such as tannin, caffeine, alkaloids, etc. in food. In particular, it is worth using in the coffee manufacturing plant.

It can also be used to remove specific proteins in sour.

(9) maintenance, moisturizers

The maintenance and moisturizing properties of chitin and chitosan can be used to prevent drying and solidification of foods.

(10) emulsifiers

The emulsification of chitin and chitosan can be useful for making foods such as creams and juices.

Mayonnaise, peanut butter, etc. in emulsion form, as an additive in food will be advantageous in many ways (with antiseptic effect).

(11) Edible coatings and packaging agents

If chitosan and polypeptide are mixed and developed as a film component, various foods can be packaged and developed as food.

(12) Functional low calorie food materials, food molding materials, nutrients, enzymes, and useful microbial carriers.

(13) It can be developed as a functional food material such as antibody productivity (enhancing) substance, metabolic accelerator, adjuvant, and digestive absorption accelerator.

(14) low calorie and extender

Mixing chitin powder with food can result in low-calorie foods, and adding it to bread dough increases its volume and increases its effectiveness.

It also has the effect of lowering cholesterol and triglycerides, which has the effect of one stone and two trillion.

(15) Functional Health Tablet

It can be refined into chitin or chitosan powder or oligosaccharide to develop antacids of excessive gastric acid, improve gastrointestinal microbial growth, and develop functional health enhancer for the weak and weak in physical strength or disease due to hypertension or other diseases. .

(16) Functional foods for removing uric acid

Chitin and chitosan are ionically bound to the dietary nucleic acid ingested in the acidic region of the stomach to excrete significant amounts of nucleic acid components into feces.

In this way, it is effective in healing gout caused by urinary acidosis by lowering the amount of uric acid in the blood and lowering the amount of purine metabolites in the urine.

(17) suppress obesity

By not directly inhibiting lipase, a serine-based enzyme, and selectively inhibiting lipase, protein hydrolysis does not occur.

(18) Improvement of carcinogen

Statistically prone to cancer is due to the acidification of the constitution.

Acidification of the constitution refers mainly to the drop in pH of the interstitial fluid or cell fluid.

This leads to the accumulation of metabolic waste products CO2 and H + ions when the blood flow is not smooth, and the pH of the interstitial fluid drops.

At this time, ingestion of chitin and chitosan, N-acetyl glucosamine or glucosamine produced by degradation stimulates parasympathetic nerves, which leads to vasodilation and also stimulates blood flow. This restores the pH of the interstitial fluid to its natural state, activating all physiological functions and activating the immune system.

This is to improve cancer constitution.

▶ Function and use of grade 100% chitosan

[Medical, Medical]

(1) anticancer drugs

Chitosan suppresses cancer cells by stimulating natural killer cells (NK Cells) that attack cancer cells. When chitosan is administered, the cancer cell removal rate is over 93%.

(2) cholesterol lowering agents

As dietary practices have become more westernized recently, chitosan lowers LDL levels and increases HDL levels, especially as it inhibits cholesterol deposition in the liver, as LDL levels are higher than HDL levels. It is effective.

(3) Osteoporosis aid

Administration of calcium and chitosan as supplements in osteoporosis patients proved to have an excellent effect.

(4) role of blood pressure regulator

The excessive intake of salt is the cause of hypertension because the chlorine ions in the salt acts to increase blood pressure. Chitosan absorbs chlorine ions to inhibit and release the intestines.

(5) Hazardous Radiation Removal

In the study of mice taking chitosan, strontium, a radioactive substance that causes bone cancer, was investigated in 2% of the strontium deposits in the bone, whereas in mice without chitosan, the deposition rate was about 10%.

(6) sympathetic nerve stimulation of chitin and chitosan

Glucosamine or N-acetylglucosamine has been shown to trigger appetite in rats.

Appetite is a phenomenon caused by stimulation of the fasting central nerve of the parasympathetic nerve and this can be called the brain activity.

While there are some appetizing drugs like this, it's no surprise that glucosamine is not a drug.

In other words, when glucosamine stimulates the parasympathetic nerve of the autonomic nerve, it acts on the fasting center of the brain, which can be said to boost appetite.

This means that ingestion of chitin and chitosan stimulates the parasympathetic nerve, which activates the body and causes various effects.

This speeds up blood flow and stimulates the division of NK cells that kill cancer cells. At the same time, the systemic immunity is enhanced and useful for the treatment of various adult diseases and intractable diseases.

On the contrary, the hasty people have sympathetic nerves that predominately slow blood circulation, resulting in acid constitution, which lowers resistance to diseases such as cancer.

(7) Use as tooth decay

The use of chitin and chitosan as a tooth decay has not yet been put to practical use, but it is expected that it will eventually be used as research progresses.

It has been reported that chitin and chitosan have the effect of inhibiting the adhesion of S. mutans' ferric layer and desorption of S. mutans once attached. (3)

▶ Example of Chitosan's use as a health food or functional food

(1) blood pressure regulators

It is known that blood pressure rise is caused by Cl ^- ion in NaCl.

Cl ^- ions to activate the conversion enzyme that converts angiotensin I to angiotensin II by a large amount of angiotensin II is produced there again this is known to stimulate aldosterone which blood pressure is rising is a positively charged chitosan with + Cl ^- in combination with the ion vitro Because it is discharged to the blood pressure can be suppressed.

In addition, it inhibits excessive consumption of insulin, thereby suppressing hypertension caused by obesity. It is also known that mineral absorption has little effect and activates white blood cells.

(2) strengthening liver function

In the rabbit experiments, high-fat diets showed no significant increase in fatty liver or hepatitis in the non-chitin and chitosan groups, but none in the chitin and chitosan groups. At the same time, the upper liver cells were easily regenerated.

(3) activation of cells

Chitin and chitosan were found to activate cells instead of having no rejection in vivo.

(4) improvement of acid constitution

It has been confirmed that the acidified constitution returns to slightly alkaline up to pH 7.4.

(5) activation of immune function

It was confirmed that T cells are activated to improve immune function.

In other words, the balance between helper T cells and suppressor T cells is well balanced among T cells, which is known to improve antibody formation.

In addition, chitin and chitosan contribute to the improvement of homeostasis.

(6) inhibitory effect of cancer

First, it has a function of suppressing toxins released by cancer cells.

In particular, inactivation of Toxohormon-L prevents the breakdown of intracellular fat and body fat and prevents the body from becoming weak.

Second, it has been confirmed that the activity of NK cells or LAK cells that kill cancer cells is increased several times.

(7) Increase of effective bacteria in intestine

Chitosan is a polymer charged with β.

It is combined with the carboxyl groups of the malignant bacteria in the intestine and is released. In addition, it is known to directly help the growth of beneficial bacteria, bifidus and lactic acid bacteria.

Next, the preparation method of the present invention is presented for each purity.

[grade 75-85% chitosan manufacturing method]

Take the back part of shell, pulverize and powder, then pharmacopoeia. It is immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral and dried.

Pharmacopeias dry samples at 100 ° C. It is immersed in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washed and dried.

The obtained chitin powder was deacetylated for 2 to 3 hours in an aqueous sodium hydroxide solution (concentration 40-50% W / V) at 110-130 ° C., washed several times with distilled water, and then aqueous acetic acid solution (concentration 2% V / V). After dissolving in the chitosan aqueous solution was prepared, the excess pharmacopoeia again. It was made into a fibrous phase in 1N aqueous sodium hydroxide solution to prepare chitosan having a deacetylation degree of about 75-85%.

[grade 85-90% chitosan manufacturing method]

Take the back part of shell, pulverize and powder, then pharmacopoeia. It is immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral and dried.

Pharmacopeias dry samples at 100 ° C. It is immersed in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washed and dried.

The obtained chitin powder was deacetylated for 2 to 3 hours in an aqueous sodium hydroxide solution (concentration 40-50% W / V) at 110-130 ° C, and washed twice until neutralized with distilled water. After dissolving in acetic acid aqueous solution (concentration 2% V / V) to prepare a chitosan aqueous solution, the excess pharmacopoeia again. It was made into a fibrous phase in 1N aqueous sodium hydroxide solution to prepare chitosan having a deacetylation degree of about 85-90%.

[Manufacturing method of grade 90-95% chitosan]

Take the back part of shell, pulverize and powder, then pharmacopoeia. It is immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral and dried.

Pharmacopeias dry samples at 100 ° C. The protein was removed by immersion for 12 hours in 1N aqueous sodium hydroxide solution, washed, and dried.

The obtained chitin powder was deacetylated for 2-3 hours at 110-130 ° C in an aqueous sodium hydroxide solution (concentration 40-50% W / V), and washed three times with distilled water until neutral. After dissolving in acetic acid aqueous solution (concentration 2% V / V) to prepare a chitosan aqueous solution, the excess pharmacopoeia. It was made into a fibrous phase in dilute aqueous alkali solution to produce chitosan having a deacetylation degree of about 90-95%.

[Manufacturing method of grade l00% chitosan]

Take the back part of shell, pulverize and powder, then pharmacopoeia. It is immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral and dried.

Pharmacopeias dry samples at 100 ° C. The protein was removed by immersion for 12 hours in 1N aqueous sodium hydroxide solution, washed, and dried.

The obtained chitin powder was deacetylated for 2-3 hours at 110-130 ° C in an aqueous sodium hydroxide solution (concentration 40-50% W / V), and washed three times with distilled water until neutral. After dissolving in acetic acid aqueous solution (concentration 2% V / V) to prepare a chitosan aqueous solution, the excess pharmacopoeia. Made in fibrous phase in 1N aqueous sodium hydroxide solution.

Thereafter, the fibrous chitosan was deacetylated again for 1 to 2 hours, and washed with distilled water to obtain 100% pure chitosan as a product.

EXAMPLE

▶ Deacetylation

[Measurement by titration]

The degree of deacetylation was determined by measuring the alkali amine groups by acid-base titration based on the method that Senju and co-workers used to measure the degree of deacetylation of chitin. (31)

After 1 g of chitin was reacted with 25 g of sodium hydroxide solution (dissolved 10 g of sodium hydroxide in 15 g of distilled water) at room temperature for 3 hours, 75 g of crushed ice was added thereto at 0 ° C. or lower, followed by stirring to dissolve an alkaline chitin solution.

Alkaline chitin solution (10 g), which had a polymer mass fraction of 0.01, was diluted with 50 g of distilled water and brought to pH 11 with 24 mL of 1N HC1.

This solution was titrated with 0.1N HC1 standard solution (factor 1.001) using a pH meter (Fisher Scientific Accumet ^R pH Meter 900).

Perform a blank test under the same conditions.

The difference between the two volumes of HC1 needed to reach the end point is directly related to the number of amine groups in the chitosan sample.

The deacetylation degree of chitin was calculated as the amount of acid consumed to liberate the amino groups in solution as follows.

Where M _N , M _G , W _A , and X _A represent the molecular weight of N-acetylglucosamine, the molecular weight of Glucosamine, the structural unit of chitosan, the mass of alkaline chitin solution, and the mass of chitin (polymer), respectively.

Since the amount of acid consumed (A mo1) corresponds to the amount of glucosamine in the hydrolyzed chitin, the total amount of glucosamine in the solution (M _GT g) can be found as the product of A and the molecular weight of glucosamine 161.

(W _A × X _A- (AB). (M _N -M _G ) -M _GT ) in the denominator is expressed as the total amount of N-acetylglucosamine.

Where B is expressed in moles of glucosamine in the starting chitin measured by the hydrolysis method 32 reported by Elek and Harte, as shown in FIG. Thus, (AB). (M _N -M _G ) means the amount of sample reduced by deacetylation.

Calculation of Deacetylation Degree

[Calculation of chitosan deacetylation degree more than 75%-less than 85%]

A = 0.000423 M _GT = 0.068103 Sampling fraction = 0.1

B = 0.000275 (moles of glucosamine units of raw chitin)

Degree of deacetylation

[Calculation of chitosan deacetylation degree over Grade 85%-Less than 90%]

A = 0.000474 M _GT = 0.076314 Sampling fraction = 0.1

B = 0.000275 (moles of glucosamine units of raw chitin)

Degree of deacetylation

[Calculation of chitosan deacetylation degree above 90%-less than 95%]

A = 0.000529 M _GT = 0.085169 Sampling fraction = 0.1

B = 0.000275 (moles of glucosamine units of raw chitin)

Degree of deacetylation

[Calculation of Pure chitosan Deacetylation Degree]

A = 0.0005493 M _GT = 0.08847 Sampling fraction = 0.1

B = 0.000275 (moles of glucosamine units of raw chitin)

Degree of deacetylation

[Measurement by Infrared Spectra]

Chitosan 3mg (200mesh) deacetylated chitin was mixed with 300mg of KBr (200mesh), and 200mg of the mixed powder was dried at 60 ° C under reduced pressure for 12 hours.The maximum size of 1nfrared Spectra of Shimadzu Co., Ltd. line) method.

The 5, 6, 7, 8, respectively deacetylation degree of 75 to 85%, 85-90%, 90-95%, are shown over a range of 1000-3000cm ^-1 Infrared Spectra for samples up to 100% Chitosan It was.

When the deacetylation degree is 100%, a CH stretching absorption band appears in the range of 2750-3000 cm ⁻¹ , especially at 2900 cm ⁻¹ .

According to Mima et al. (36), within this range, the analytical results are due to crystallization.

This crystallization also causes changes in other vibration regions.

As shown in each figure, similar trends with the 2900 cm ^-1 band appear at 1310 cm ^-1 and 1380 cm ^-1 , and it can be seen that the absorption peak of chitin at each wavelength gradually decreases as the degree of deacetylation increases.

Infrared Spectra in the range 1500-1700 cm ^-1 shows that the chitosan prepared by the present invention is almost 100% deacetylated.

The amide I bands attributable to the C-2 acetamide (N-acetyl) group of the chitin appear at 1560 cm ^-1 and 1650 cm ^-1 , which are consistent with the wavelengths of the C = O band (33-36).

A weak absorption peak was observed in the chitin spectrum, but no absorption peak was observed in the spectrum of 100% deacetylated chitosan, indicating that the sample was completely deacetylated.

In addition, the COC band appeared at 1080cm ^-1 , and the absorption peak gradually decreased with increasing degree of deacetylation, and at the same time, the CO2 ^- band was observed at 1420cm ^-l . The absorption peak increased with increasing degree of deacetylation. It can be seen.

As described above, the present invention provides a method for producing high quality chitosan having a deacetylation degree of 75-100% in a short reaction time on a low reaction temperature and a low concentration of sodium hydroxide as described above. The high purity chitosan obtained through the present invention has a characteristic that can be mass-produced with the phase effect and has a useful effect that the application range (usage range) as a new material is greatly expanded.

For reference, the structural formula according to the degree of deacetylation of the present invention.

[constitutional formula]

▶ Structural formula of grade 75 ~ 85% chitosan

▶ Structural formula of grade 85 ~ 90% chitosan

▶ Structural formula of grade 90 ~ 95% chitosan

▶ Structural formula of 100% purity chitosan

Claims (4)

Take the back part of shell, pulverize and powder, then pharmacopoeia. Immerse in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, wash with distilled water until neutral and dry, and then dry sample at 100 ° C. Deacetylation of the chitin powder obtained by immersing in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washing and drying in the aqueous solution of sodium hydroxide (concentration 40-50% W / V) at 110-130 ° C for 2-3 hours After the reaction, the solution was washed several times with distilled water and dissolved in an aqueous acetic acid solution (concentration 2% V / V) to prepare an aqueous chitosan solution, followed by excess pharmacopoeia. A process for preparing chitosan having a deacetylation degree of about 75-85% by making it into a fibrous phase in 1N aqueous sodium hydroxide solution. Take the back part of shell, pulverize and powder, then pharmacopoeia. Immersed in 2N hydrochloric acid aqueous solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral, dried, and then dried sample at 100 ° C. Deacetylation of the chitin powder obtained by immersing in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washing and drying in the aqueous solution of sodium hydroxide (concentration 40-50% W / V) at 110-130 ° C for 2-3 hours After the reaction was repeated twice, and washed with distilled water until neutral, dissolved in an aqueous acetic acid solution (concentration of 2% V / V) to prepare a chitosan aqueous solution, and then the excess pharmacopoeia. A process for preparing chitosan having a deacetylation degree of about 85-90% by making it into a fibrous phase in 1N aqueous sodium hydroxide solution. Take the back part of shell, pulverize and powder, then pharmacopoeia. Immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral, dried, and then dried sample at 100 ° C. Deacetylation of the chitin powder obtained by immersing in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washing and drying in the aqueous solution of sodium hydroxide (concentration 40-50% W / V) between 110-130 ° C for 2-3 hours After the reaction was repeated three times, and washed with distilled water until neutral, dissolved in an aqueous acetic acid solution (concentration of 2% V / V) to prepare a chitosan aqueous solution, and then the excess pharmacopoeia. A process for preparing chitosan with a deacetylation degree of about 90-95% by making it into a fibrous phase in dilute aqueous alkali solution. Take the back part of shell, pulverize and powder, then pharmacopoeia. Immersed in 2N aqueous hydrochloric acid solution for 12-16 hours to remove calcium and ash, washed with distilled water until neutral, dried, and then dried sample at 100 ° C. Deacetylation of the chitin powder obtained by immersing in 1N aqueous sodium hydroxide solution for 12 hours to remove the protein, washing and drying in the aqueous solution of sodium hydroxide (concentration 40-50% W / V) at 110-130 ° C for 2-3 hours After the reaction was repeated three times, and washed with distilled water until neutral, dissolved in an aqueous acetic acid solution (concentration of 2% V / V) to prepare a chitosan aqueous solution, and then the excess pharmacopoeia. A method of preparing chitosan having a deacetylation degree of 100% by making a fibrous phase in an aqueous solution of 1N sodium hydroxide, followed by deacelylation of chitosan on the fibrous phase for 1 to 2 hours, followed by distilled water washing.

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