Chitosan chromate, synthesis method thereof and energy-intensive composition containing said chitosan chromate

FIELD: chemistry.

SUBSTANCE: method of producing chitosan chromate involves reaction of soluble chitosan salts with metal chromates in ratio of 2 moles of the chitosan cation to 1 mole of chromate anion or with metal bichromates in ratio of 4 moles of the chitosan cation to 1 mole of the bichromate anion. The solid chitosan chromate residue formed is then separated and dried at temperature not higher than 150°C. The invention discloses an energy-intensive composition based on chitosan dodecahydro-closo-dodecaborate containing an effective amount of chitosan chromate. The quantitative ratio in the energy-intensive composition is by the required combustion mode: the higher the content of chitosan chromate, the higher the activity of the composition.

EFFECT: invention enables to obtain a chemical compound having sufficiently high oxidative properties and suitable for use in energy-intensive compositions which burn without emitting harmful gaseous products.

3 cl, 5 ex

 

The invention relates to the chemistry of carbon, specifically to obtain the chromate chitosane, which may find application as an active oxidizing component in a variety of energetic condensed systems (ECS), such as powders, pyrotechnic and explosive compositions and composite solid rocket fuels.

It is known that chitosan C6O4H9NH2as the base, due to the presence in its composition of amino groups capable of protonemata when interacting with acids with the formation of singly charged cation chitosane C6O4H9NH3+forming soluble and water-insoluble salts (Chitin and chitosan: synthesis, properties and applications / edited Kgosana, Gasiorowski, Wepfeemia. - M.: Nauka, 2002. 366 C.).

Soluble salts of chitosan is produced by interaction of chitosan with the appropriate acid taken in a stoichiometric ratio according to the following reaction equation:

where a is CH3Soo-, Cl-, NO3-and others.

Formed as a result of interaction of initial substances, the solution is evaporated to dryness and the solid residue salt of chitosan.

Insoluble salts, such as sulfate, chitosan, obtained by interaction of a solution containing a soluble salt of chitosan, rest the rum, containing sulfate anion, taken in a stoichiometric ratio according to the following reaction equation:

The precipitation of chitosan sulfate is filtered off, washed with water and dried.

The disadvantage of most salts of chitosan is relatively low oxygen content and the lack of even a mild oxidizing properties, which is an obstacle to the use of salts of chitosan as an active oxidizing components of the energy-intensive structures.

Know the use of chromates and bichromates as oxidizers in various FORMER, in particular pyrotechnic and match the compositions in solid fuels for generators and rocket engines. Education in the combustion products of chromium oxide (III) increases the speed and completeness of combustion of the primary fuel (Energy condensed systems. Brief encyclopedic dictionary. Edited Bpeuropa. M: the Janus-K. 2000. S).

Chromates is produced by interaction of solutions of chromic acid (H2CrO4or chromium oxide CrO3with oxides, hydroxides, carbonates of the respective metals or ammonium, as well as deposition from solutions of salts of chromate sodium Na2CrO4or oxidation of chromium compounds lower valences. Bichromate, salt darmowej acid (H2Cr2O7

Sufficiently high oxidative properties of chromates and bichromates metals or ammonium caused not only by the oxygen content in the corresponding anions, but also the ability of chromium in oxidation state (VI), in which he is chromates and bichromate, move under certain conditions (pH, presence of reducing agents and their resilience in chrome compounds with oxidation state (III) or (0).

The prior art perchlorate chitosane composition C6O4H9NH3ClO4the method of its production and energy-intensive composition containing the perchlorate chitosane (U.S. Pat. Of the Russian Federation No. 2315774, publ. 27.01.2008), which is the closest to the claimed invention.

According to this invention, the perchlorate chitosane get the interaction of chitosan with a solution of chloric acid HClO4when the molar ratio of the initial reagents 1 to 1. From the reacted mixture of the target product are evaporation, followed by drying.

Due to the high oxidizing properties perchlorate chitosane can be used in energy-intensive structures.

However, a significant shortcoming of the perchlorate chitosane as oxidant in energy-intensive part is the selection in the process of combustion of the gaseous Gloria hydrogen chloride, represents an environmental hazard.

Object of the invention is a receipt containing the chromate anion new chemical compounds that have high enough oxidizing properties and is suitable for use in energy-intensive structures, without burning the selection of environmentally harmful gaseous products.

The problem is solved offered by the chromate chitosane composition (C6O4H9NH3)2CrO4and the method of its production, including the interaction of soluble salts chitosane with metal chromates, taken in the ratio of 2 moles of the cation chitosane on 1 mol of the chromate anion, or bichromate metals in relation to 4 mol of the cation chitosane on 1 mol of the bichromate-anion, subsequent separation of the resulting target product - chromate chitosane solid and drying at a temperature not higher than 150°C.

The claimed compound, its properties and how to obtain it accessible to the applicant the information sources described previously were not.

Chromate chitosane is non-toxic, explosion-proof, resistant to moisture, heat and mechanical stress connection. The Tg shows that its decomposition at temperatures above 150°C flows smoothly (without explosion or flash). Test impact-testing machine (Horst A.G. Gunpowder and explosive substances is TBA. M: Barongis, 1975. 187 C.) showed that the connection is stable when the drop weight 10 kg from a height of 400 mm (maximum height, which is achieved using existing impact-testing machine). Keeping the chromate chitosane in a humid atmosphere leads to a slight increase in weight (within 5%), without decomposition or hydrolysis, and the absorbed moisture can be easily removed by drying. While the chromate chitosane has a sufficiently high oxidizing properties that enable its use as a component of the energy-intensive compositions which burn without releasing harmful gaseous products of its decomposition.

The development of the method of production of new chemical compounds, chromate chitosane composition (C6O4H9NH3)2CrO4preceded experimental studies on the interaction of chitosan with the chromate and bichromate-anions, razyasnenie a number of questions, the answers to which could not be deduced only from logical reasoning. First, because CrO42-and Cr2O72-anions are, in most cases, oxidative properties, it was necessary to test the stability of chitosan against these oxidants, as it is known, that under action of chitosan some oxidants, such as periodate or sodium peroxide, is a polymer chain that is alglucosidase with the formation of the oxidized chitosan (VI Chursin Properties and application of oxidized chitosan. // Proc. Dokl. Ninth international conference "Modern perspectives in the study of chitin and chitosan. Stavropol, 2008. M: VNIRO. 2008. P.113-115.). Secondly, in the absence of redox interactions and the formation of salts was difficult to state unequivocally whether they dissolve in water, which is necessary to develop a method of synthesis of these compounds.

As a result of investigations of the interaction of chitosan with anions CrO42-and Cr2O72-it is established that in both cases, high yield is the formation of water-insoluble chromate chitosane according to the following equations:

Based on theoretical notions one might expect the formation of chromate and bichromate of chitosane respectively, however, experimental studies have confirmed theoretical assumptions about the educational opportunities of bichromate of chitosane.

The formation of the chromate chitosane in both cases is confirmed by the chemical analysis of the precipitate formed and output, as well as acidification of the solution due to the formation of the acid (proton) in the case of bichromate in accordance with the equation (4).

the Method of producing the chromate chitosane as follows. Prepare soluble salt of chitosan, such as the acetate chitosane. To do this, dissolve a portion of chitosan in acetic acid. To the resulting solution was added a solution of chromate or bichromate of sodium containing reagents in the required quantities for the formation of the chromate chitosane according to equations (3) or (4). The combined solution is thoroughly mixed, the precipitation of chromate chitosane filtered off, washed from side products of the reaction and dried to constant weight by heating to a temperature not exceeding the decomposition temperature of the chromate chitosane. According to differential thermal analysis of the decomposition of the target product - chromate chitosane with mass loss begins at temperatures above 150°C.

In appearance and properties of the chromate chitosane sharply differs from the original chitosan and chromium, or bichromate used for its synthesis. Chromate chitosane is a brittle solid product, breaking up breaking them into pieces of irregular shape, shiny on the breaks. Color plate pieces dark brown, three-dimensional - almost black. When grinding the pieces of the chromate chitosane with crunch and scatter fray in fine brown powder.

According to diffraction (DRON - 3,0, λCuKα) new connection rangeroamer is about, which is typical of the salts of chitosan, and reflection, which gives the original chitosan, are absent. IR-spectrum (IFS EQUINOX-55S) chromate chitosane (C6O4H9NH3)2CrO4contains band in the range of 1518, 1616, 3187 and 3519 cm-1characterizing the cation chitosane (Wealden, Lnegative, Umiliana. The reaction of dodecahydro-closo-dodecaborane acid with chitosan. // Journal of structural chemistry. 2006. T. No. 1. P.41-46.). According to IR spectroscopy the presence of absorption bands in the region 892 cm-1related to the stretching vibrations of CrO42-anion, confirms its occurrence in the structure of the claimed compounds, but not Cr2O72-anion, because the absorption bands in the region 949 and 762 cm-1characterizing the bichromate-anion, in the IR spectrum are missing.

Salt of the chromate chitosane does not contain crystallohydrates water, inert to atmospheric moisture, does not explode upon impact, friction and other mechanical effects, is non-toxic. When heated pure individual chromate chitosane ranging from 150°C, it is quiet decomposition without flares and explosive emission. After annealing in air at 800 to 900°C To form the remainder of a dark green colour, which according to diffraction is an oxide of chromium (III) Cr2O3. Atomic absorption analysis method (spectrophotometry is the EPR AA-780) solution Cr 2O3sulfuric acid is found that the chromate anion quantitatively transferred into the chromium oxide.

The proposed chromate chitosane exhibits sufficiently high oxidative properties. In mixtures of the chromate chitosane with such well-known combustible components and pyrotechnic incendiary compositions, as red phosphorus, sulphur, sulphide of antimony Sb2S3and others get actively oxidizing materials. However, depending on the ratio of the chromate chitosane and the combustible component decomposition can be in the form of rapid combustion, and flash (explosion).

The advantage of the chromate chitosane compared with the perchlorate chitosane is the absence of toxic gaseous emissions of chlorine-containing compounds.

It is known that in some cases the presence of soot in the combustion products of the FORMER improves the conditions for oxidation of the primary fuel.

The advantage of the chromate chitosane (C6O4H9NH3)2CrO4compared with other known oxidants, including chromates and bichromates metals or ammonium, used in the composition of the FORMER, is the allocation of sooty residue, which improves the combustion efficiency of fuel.

The chemical composition of the claimed chromate chitosane (C6O4H9NH3)2CrO4determine using shadowshadow.

Analysis for carbon, hydrogen and nitrogen is carried out by the known methods of microanalysis of organic substances (Mazor L. Methods of organic analysis. M.: Mir, 1986. S). The content of the chromate ion is calculated based on the weight of the resulting residue, which is a chromium oxide Cr2O3. The oxygen content chitosanase cation find the difference.

The objective of the invention is solved also offer energy-intensive composition containing the chromate chitosane.

It is known the use of compounds of dodecahydro-closo-dodecaborate chitosane composition (C6O4H9NH3)2In12H12as energy-intensive component of high-energy materials (U.S. Pat. Of the Russian Federation No. 2158221, publ. 27.10.2000). Due to the specific structure of this compound is thin at the molecular level, the distribution of fuel (B12H122--anions) and oxidant (oxygen-containing groups of chitosan), the flow of oxygen and air to the combustion, expansion when heated with a sharp increase in the volume of the burning material, creates favorable conditions for rapid and full flow terrogation the combustion reaction. When ignited (C6O4H9NH3)2In12H12ignites and burns vigorously with the formation of black residue, representing the cm is camping soot and boric anhydride and/or boric acid. However, because the compound has a relatively high flash point (300°C), this limits the possibility of its use as an energy-intensive component of energy-efficient materials.

Closest to the claimed energy-intensive composition is a composition based on dodecahydro-closo-dodecaborate chitosane (C6O4H9NH3)2B12H12containing the perchlorate chitosane C6O4H9NH3ClO4the effective amount (U.S. Pat. Of the Russian Federation No. 2315774, publ. 27.01.2008).

A disadvantage of known composition are harmful chlorine-containing gaseous emissions in the combustion process energy-intensive structure.

To eliminate this drawback is proposed energy-intensive structure on the basis of dodecahydro-closo-dodecaborate chitosane (C6O4H9NH3)2B12H12containing the chromate chitosane (C6O4H9NH3)2CrO4in effective amounts, determined the required character burning.

Unlike the individual components of the structure - (C6O4H9NH3)2CrO4and (C6O4H9NH3)2In12H12, the claimed composition is generally characterized by a much higher energoactivity and complete combustion. As studies have shown, SOS is AB has a lower flash temperature (about 240°C) compared to the individual components. This is due to the structure of the resultant composition, which is a uniformly distributed mixture of oligomers of chitosan salts B12H122and CrO42-anions.

CrO42-anions are more rich in oxygen and stronger oxidant than oxygen-containing groups of the chitosan. Therefore, by heating such compounds ignition (C6O4H9NH3)2In12H12occurs at lower temperatures, and its combustion is much more intensive than in individual form. The activity of compounds is determined by the ratio of In12H122-anions, which act as fuel and CrO42-anions of the chromate chitosane exhibiting oxidative properties. Since dodecahydro-closo-dodecaborate chitosane very deficient in oxygen, when the number of the chromate chitosane activity of the claimed compounds is growing. The specific composition is determined depending on the desired combustion mode (slow, fast, or explosion): if necessary, explosive character increase concentration in a mixture of chromate chitosane, and to provide a more relaxing type of combustion - the concentration of dodecahydro-closo-dodecaborate chitosane.

According to the invention C is demonstrate the composition of a common deposition of the chromate chitosane with dodecahydro-closo-dodecaborates chitosane, taken in a predetermined ratio. Uniform distribution of salts is due to the fact that In12H122-anions are electron-deficient systems, unlike CrO42-anions containing in its structure a large number of donor atoms of oxygen with the unshared pair of electrons. Therefore, when the evaporation of water is the convergence of oligomers of salts due to donor-acceptor interaction B12H122-and CrO42-anions.

Compared to energy-intensive composition containing the perchlorate chitosane (U.S. Pat. Of the Russian Federation No. 2315774, publ. 27.01.2008), the proposed energy-intensive composition during combustion does not emit into the atmosphere of harmful impurities, due to the presence in its composition of the chromate chitosane.

The properties of the proposed structure: flash point (about 240°C), the activity and the completeness of combustion, comparable with the properties of known composition.

Thus, the technical result of the claimed invention to provide new chemical compounds, chromate chitosane that has a sufficiently high oxidizing properties and is suitable for use in energy-intensive structures, burn without releasing harmful gaseous products, due to the presence of energy-intensive part of the chromate chitosane.

The opportunity to undertake the surveillance of the invention is illustrated by examples, which describes the obtaining of the chromate chitosane (examples 1-3) and the energy-intensive preparation of the composition (examples 4, 5).

As a source of chitosan to obtain soluble salts of chitosan, which are then used in the synthesis of the chromate chitosane taken the product produced by LLC "Biopolymers" (bartizans Primorsky Krai) TU 9283-174-200472012-03 with a degree of dezazetilirovanie 75,0%, having the following elemental composition, wt.%: WITH AND 45.5; H - 6,8; N - 8,1; 39,6. This corresponds to the gross formula C6,5O4,25H9,5NH2.

Example 1. To 200 ml of a solution containing 1,03365 g (6,02 mg-mol) of the hydrochloride chitosane6,5O4,25H9,5NH3Cl, poured with vigorous stirring to 200 ml of a solution containing 0,70450 g (3,01 mg-mol) 4-water chromate sodium Na2CrO4×4H2O. This corresponds to their molar ratio of 2 to 1, i.e. the stoichiometry of reaction (3). The resulting fine precipitate of brown-yellow filtered, washed with water prior to the absence in the lavage Na+and dried at a temperature of about 105°C to constant weight. Get 1,26390 g (2,74 mg-mol) of the chromate chitosane (C6,5O4,25H9,5NH3)2CrO4that corresponds 91,0%increase yield of the target compound.

Calculated for (C6,5O4,25H9,5NH3)2CrO4, wt.%: With - 33,9; 5,5; N - 6,0; Cr - 11,3; O - 43,3.

Nai is prohibited for (C 6,5O4,25H9,5NH3)2CrO4, wt.%: With To 33.8; H - 5,5; N - 5,9; Cr - 11,3; 43,5.

Example 2. Spend the interaction between 1,18340 g (6,17 mg-mol) hydrohloride chitosane C6,5O4,25H9,5NH3F and 0,72090 g (is 3.08 mg-mol) 4-water chromate sodium Na2CrO4×4H2O, which corresponds to a small excess chitosan salt, and allocate the sediment, as described in example 1. Get 1,28615 g (2,79 mg-mol) of the chromate chitosane (C6,5O4,25H9,5NH3)2CrO4that corresponds to its 90,5%final output.

Calculated for (C6,5O4,25H9,5NH3)2CrO4, wt.%: With - 33,9; 5,5; N - 6,0; Cr - 11,3; O - 43,3.

Found for (C6,5O4,25H9,5NH3)2CrO4, wt.%: With - 33,9; N - 5,4; N - 6,1; Cr - 11,4; 43,2.

Example 3. Spend the interaction between 1,15000 g (5,52 mg-mol) of the hydrochloride chitosane C6,5O4,25H9,5NH3Cl and 0,40600 g (1,38 mg-mol) of potassium bichromate K2Cr2O7that corresponds to the stoichiometry of reaction (4), then allocate the sediment, as described in example 1. Get 1,23510 g (1.24 mg-mol) of the chromate chitosane (C6,5O4,25H9,5NH3)2CrO4that corresponds to its 89,9%final output.

Calculated for (C6,5O4,25H9,5NH3)2CrO4, wt.%: With - 33,9; 5,5; N - 6,0; Cr - 11,3; O - 43,3.

Found for (C6,5O4,25H9,5NH3)2CrO4, wt.%: With - 33,8; N - 5,4; N - 6,1; Cr - 11.4; - 43,3.

Example 4. To 10 ml creamy solution containing 0,73090 g (1,50 mg-mol) their fine (C6,5O4,25H9,5NH3)2B12H12) add 10 ml creamy solution containing 0,23070 g (0.50 mg-mol) their fine (6,5O4,25H9,5NH3)2CrO4(molar ratio 3:1) and mix thoroughly. The resulting mixture is filtered and dried at a temperature of 100-110°C. Receive 0,96160 g brown product in the form of a curved towards the edges of the compact round brown pill. The flash point of 240°C. the Decomposition takes place in the form of rapid combustion.

Example 5. Cook the mixture 0,50365 g (1,03 mg-mol) (C6,5O4,25H9,5NH3)2B12H12and 0,47525 g (1,03 mg-mol) (C6,5O4,25H9,5NH3)2CrO4(molar ratio 1:1), as described in detail in example 4. The flash point of 240°C. the Decomposition takes place in the form of a bright flash with a Bang and scattering decomposition products.

1. Chromate chitosane composition (C6O4H9NH3)2CrO4.

2. The method of obtaining the chromate chitosane composition (C6O4H9NH3)2CrO4including mutual the action of soluble salts chitosane with chromates metals in the ratio of 2 moles of the cation chitosane on 1 mol of the chromate anion or bichromate metals in the ratio of 4 moles of the cation chitosane on 1 mol of the bichromate-anion, subsequent separation of the resulting solid precipitate of the chromate chitosane and drying at a temperature not exceeding 150°C.

3. Energy-intensive structure on the basis of dodecahydro-closo-dodecaborate chitosane (C6O4H9NH3)2B12H12,containing the chromate chitosane (C6O4H9NH3)2CrO4in an effective amount.



 

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4 cl, 1 tbl, 9 ex

FIELD: chemistry and technology of derivatives of polysaccharides, chemical technology.

SUBSTANCE: invention relates to methods for preparing chitosan esters. Invention describes a method for preparing chitosan polyethylene glycol ester that involves dissolving chitosan in acetic acid followed by alkalization. Then the reaction mixture is subjected for effect of ethylene oxide under pressure 1-3 atm and temperature 60-100°C, and the concentration of reaction mass is corrected by addition of distilled water up to the density value of solution 1.030-1.032 g/cm3. Then the reaction mass is purified by electrodialysis at the rate value of solution in treatment chambers 3.0 cm/s, not less, temperature 20-45°C, the current density value 0.25-0.75 A/dm2 and the constant volume of the reaction mass. Method provides enhancing the effectiveness of purification by electrodialysis due to reducing energy consumptions. Chitosan esters can be used in medicine, cosmetics, food and chemical industry.

EFFECT: improved preparing method.

5 ex

Modified chitosan // 2269542

FIELD: organic chemistry of natural compounds, chemical technology, medicine.

SUBSTANCE: invention relates to the group of chitosan-containing compounds. Invention relates to synthesis of modified chitosan of the following structure: wherein n = 150-1400. The modified chitosan possesses the bactericidal activity, in particular, antituberculosis activity.

EFFECT: valuable medicinal properties of modified chitosan.

1 tbl, 1 dwg, 3 ex

FIELD: natural compounds technology.

SUBSTANCE: chitosan preparation process comprises breaking naturally occurring chitin-containing material, charging it into reactor, demineralization with 6-7% aqueous hydrochloric acid, deproteination with sodium hydroxide solution at 85-95°C, deacetylation with sodium hydroxide solution on heating, decoloration, and washing with water after each stage to pH 6.5. Process is characterized by that chitin-containing material broken to achieve fraction 0.5-6 mm is fed simultaneously into a number of reactors, wherein demineralization is effected with aqueous hydrochloric acid stream at 85-95°C for 1.5 h while controlling pH in each reactor exit to achieve acid concentration in each reactor exit the same as concentration of the initial acid by way of feeding it in a continuous manner. In addition, deproteination is carried out with 6-7% sodium hydroxide solution stream for 1.5 h followed by discharging treated material into autoclave to perform deacetylation simultaneously with decoloration using 50% sodium hydroxide solution at 130-140°C in inert gas environment and in presence of 3-5% hydrogen peroxide solution used in amount 3-5% of the total volume of mixture.

EFFECT: enhanced process efficiency.

1 dwg

FIELD: chemical technology.

SUBSTANCE: invention relates to methods for preparing water-soluble saline complexes (associates) of hyaluronic acid with d-metals of IV, V and VI periods of Mendeleyev's periodic system of elements that can be used in pharmacology and cosmetology. Invention describes a method for preparing water-soluble saline complexes of hyaluronic acid involving preparing an aqueous solution of salt of d-metal of IV, V and VI periods of periodic system and its mixing with hyaluronic acid sodium salt, holding the mixture, its stirring, dilution with water and isolation of the end product. For mixing method involves using the amount of aqueous salt of abovementioned d-metal that is equivalent to the amount of carboxy-groups of hyaluronic acid sodium salt or in the limit from 0.95 to 1.10. After dilution with water the solution mixture is subjected for ultrafiltration on separating membranes with simultaneous washing out with aqueous salt solution of abovementioned d-metal firstly and then with deionized water followed by concentrating the product. By another variant for mixing the method involves the amount of aqueous solution of d-metal salt lesser of the equivalent amount of carboxy-groups in hyaluronic acid sodium salt. After dilution with water the mixture is subjected for ultrafiltration on separating membranes with simultaneous washing out with deionized water followed by concentrating the product also. Method is characterized by the decreased time of processes and simplicity.

EFFECT: improved preparing method.

2 cl, 1 tbl

FIELD: medicine, food processing industry, in particular production of depolymerized chitosane and products based on the same.

SUBSTANCE: claimed method is based on using of chitosanase in acetic acid medium and spray drying of and depolymerized chitosane and is characterized in that obtained depolymerized chitosane is preliminary converted in non-ionized form by neutralizing of bound acetic acid with ammonium hydroxide followed by precipitation in ethanol and air drying. Further interaction is carried out with ammonium lipoate or glutathione in aqueous medium. Claimed products may be used individually or in combination with other components.

EFFECT: new products for food processing industry and medicine.

4 cl, 2 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing modified glycosaminoglycans possessing analgesic properties. Method involves interaction of glycosaminoglycans with 1-phenyl-2,3-dimethyl-4-aminopyrazolone-5-(4-aminoantipyrine) in aqueous medium at pH = 4.7-4.8 in the presence water-soluble 1-ethyl-3-[3-(dimethlamino)propyl]carbodiimide as a condensing agent at room temperature followed by purification from low-molecular reagents. Method involves a single step that simplifies technology in preparing modified glycosaminoglycans.

EFFECT: improved preparing method.

3 ex

FIELD: natural substances, chemical technology.

SUBSTANCE: invention relates to a method for preparing chitosan and purification from components of the reaction mixture - low-molecular products of deacetylation and alkali excess. Invention relates to a method for purifying chitosan prepared by solid-state method involving treatment of reaction mass with extractant consisting of 3.3-20.0% of water, 32.2-57.1% of ethyl acetate and 24.6-64.5% of ethanol at the extractant boiling point. Also, invention relates to a method for purifying chitosan prepared by suspension method and involving treatment of the reaction mass with ethyl acetate and the following treatment with extractant consisting of 6.2-25.0% of water, 12.5-62.5% of ethyl acetate and 31.3-62.5% of ethanol at the extractant boiling point.

EFFECT: improved isolating and preparing method.

3 cl, 2 tbl, 1 dwg

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