Hexamethylenetetramine. Hexamethylentetraminum methenamine

Hexamethylenetetramine is a product of the reaction of a solution of formaldehyde with ammonia. It was first obtained by A. M. Butlerov (1860), but only 35 years after its discovery it began to be used in medicine. Raw materials for semi-

To test hexamethylenetetramine, use a 40% solution of formaldehyde in water and ammonia water. 25% ammonia water is added to the formaldehyde solution, the mixture is stirred and the temperature is maintained within 40-50 °C.

After the reaction is complete, the reaction mixture should be alkaline and smell of ammonia. Activated carbon is added to the mixture, filtered, and the filtrate is evaporated in vacuum to a paste. When cooled, hexamethylenetetramine crystals crystallize. They are sucked off, washed and dried at a temperature of 30-35 ° C. The resulting hexamethylenetetramine is recrystallized from alcohol.

Hexamethylenetetramine is a white crystalline powder, very hygroscopic. Has no smell. The taste is pungent, sweet at first, then bitter. The drug is highly soluble in water and alcohol, soluble in chloroform, and almost insoluble in ether. Aqueous solutions of hexamethylenetetramine have a slightly alkaline reaction. When heated, they evaporate without melting. When aqueous solutions of hexamethylenetetramine are heated, it hydrolyzes to form formaldehyde and ammonia.

In an acidic environment, hexamethylenetetramine decomposes with the release of formaldehyde. When an alkali solution is added to the reaction mixture, the smell of ammonia is felt.

This reaction is given by GF X as an authenticity reaction to hexamethylenetetramine.

When heated with salicylic acid in the presence of concentrated sulfuric acid, a violet-red color is formed.

The reaction is based on the release of formaldehyde, which, with salicylic acid in the presence of sulfuric acid, forms an auric dye (see authenticity reactions Solutio Forma ldehydi)

Hexamethylenetetramine is a monoacid base,

tertiary nitrogen gives it basic properties, therefore, with acids it forms double salts, for example, hexamethylenetetramine hydrochloride (CHLH-HC!. The presence of tertiary nitrogen, like in alkaloids, also causes the formation of picrates (yellow precipitate), tetraiodides (CH2)b-14 and other reaction products Hexamethylenetetramine has the ability to form complex compounds with silver, calcium and phosgene salts.

Regarding the good quality of the drug, GF X requires the absence of organic impurities and impurities of ammonium salts (yellow coloring should not appear from the addition of Nessler's reagent to the drug solution when heating Nessler's reagent), paraform impurities (clouding of the solution from adding Nessler's reagent when heating). Impurities of chlorides, sulfates, and heavy metals are allowed within the limits of the corresponding standards.

The quantitative content of the drug can be determined by the neutralization method. A sample of the drug is heated with a certain amount of a titrated solution of sulfuric acid; after cooling the mixture, the excess acid is titrated with alkali using methyl red. In parallel, under the same conditions, a control experiment is carried out (pharmacopoeial method).

Hexamethylenetetramine as a base can be titrated with an acid against a mixed indicator (methylene blue and methyl orange) until the color changes from green to blue-violet.

This method is less accurate than the first, but it is quite widely used in the rapid analysis of medicinal mixtures.

Hexamethylenetetramine is used as a disinfectant. Its action is based on the formation of formaldehyde in an acidic environment, which has a disinfectant effect. Used for urinary tract diseases. It should be taken into account that if the urine is not acidic, the drug is ineffective, since it will not break down into formaldehyde. Along with the antiseptic effect, hexamethylenetetramine exhibits to some extent an anti-odagric effect, so it is also used for rheumatism.

Hexamethylenetetramine is also widely used as an anti-influenza agent. The drug is prescribed orally in powders and tablets and intravenously in the form of a 40% solution.

Available in powder and tablets of 0.25 and 0.5 g, as well as in ampoules of 5-10 ml of 40% solution. Should be stored in well sealed jars.

1. Refractometric method.

A 0.06 g sample of powder is shaken with 1 ml of water and filtered. The refractive index of the aqueous filtrate (sodium bicarbonate) is determined.

Another 0.1 g sample of powder is shaken with 1 ml of ethanol and filtered. The refractive index of the resulting alcohol solution (phenyl salicylate) is determined. In parallel, under the same conditions, the refractive indices of solvents - water and alcohol - are determined.

The amount of each component is calculated individually using the formula

2. Titrimetric method.

Sodium bicarbonate. A 0.05 g sample of powder is shaken with 2-3 ml of water and filtered. The filtrate is titrated with 0.1 N HC1 solution in the presence of methyl orange indicator.

Phenyl salicylate.

1. The residue on the filter is dissolved in 5 ml of 0.1 N sodium hydroxide solution, boiled for about 30 minutes, the excess alkali is titrated with 0.1 N HCl solution in the presence of the phenolphthalein indicator until it becomes discolored. E = M.m.

2. The residue on the filter is dissolved in 5 ml of 10% sodium hydroxide solution, boiled for 10-15 minutes, neutralized. HCl, add an excess of 0.1 N solution of potassium bromate, potassium bromide, acidify with sulfuric acid, stir, leave for 10 - 15 minutes, then add a 10% solution of potassium iodide to the mixture, shake, leave for 5 minutes. The released iodine is titrated with 0.1 N sodium thiosulfate solution (starch indicator). E= M.m./12

7. PHENYLSALICYLATE

HEXAMETHYLENETETRAMINE 0.3 EACH

Authenticity:

Add 3-4 drops of conc. to 0.1 g of powder. sulfuric acid, heated - a pink color appears in the aurine dye, in the formation of which both phenyl salicylate and formaldehyde, released during the acid hydrolysis of heceamethylenetetramine (urotropine), take part.

quantitation

1. Refractometric method.

A 0.08 g sample of powder is dissolved in 1 ml of alcohol and the refractive index of the resulting alcohol solution is determined.

Another 0.08 g sample is treated with 1 ml of water, filtered, and the refractive index of the aqueous filtrate (hexamethylenetetramine) is determined.

The amount of hexamethylenetetramine is calculated according to the formula (No. 1), phenyl salicylate according to the formula (No. 2) given above.

2. Titrimetric method.

Hexamethylenetetramine. After extraction with water, it is determined by the neutralization method (titration with HC1 solution in the presence of a methyl orange indicator or a mixed indicator).

Phenyl salicylate. The filter residue is determined by neutralization or bromatometry (the methods are described in detail for dosage form No. 4).

Factors for increasing the refractive index of aqueous and alcohol solutions
Concentration in %	Hexamethylenetetramine	Sodium bicarbonate	Phenyl salicylate
	water	alcohol	water	alcohol
	0,00166	0,00150	0,00136	0,00190
	0,00165	0,00149	0,00135	0,00189
	0,00164	0,00148	0,00134	0,00188
	0,00163	0,00147	0,00133	0,00187
	0,00162	0,00146	0,00132	0,00186
	0,00161	0,00145	0,00131	0,00185
	0,00160	0,00144	0,00130	0,00184
	0,00159	0,00143	0,00129	0,00183
	0,00158	0,00142	0,00128	0,00182
	0,00157	0,00141	0,00127	0,00181

TOPIC: APPLICATION OF REFRACTOMETRY TO DETERMINE

Hexamethylenetetramine

Are common
Hexamethylenetetramine



Systematic name	1,3,5,7-tetraazocyclodecane
Traditional names	Hexamine, methenamine
Chemical formula	C6H12N4
Physical properties
Molar mass	140.2 g/mol
Thermal properties
Classification
Reg. CAS number	100-97-0
SMILES	C1N2CN3CN1CN(C2)C3

Hexamethylenetetramine(( 2) 6 4, or C 6 H 12 N 4), ( urotropin, hexamine, English: Methenamine (INN), 1,3,5,7-tetraazaadamantane, hexamethylenetetramine or hexametylenetetramine). Used in medicine under the international nonproprietary name (INN) methenamine.

Getting and properties

It was first obtained by the Russian chemist A.M. Butlerov in 1859. Formed by the interaction of ammonia (4 mol) with formaldehyde (6 mol). White crystalline substance, sublimates at 270°. Easily soluble in water, alcohol, soluble in chloroform, slightly soluble in ether.

Heat of combustion 30.045 MJ/kg

The largest producer of hexamine in Russia is Gubakha OJSC Metafrax.

Application

Polymer production

Used in the production of phenol-formaldehyde resins,

Medicine

Hexamethylenetetramine is one of the very few synthetic drugs in use today, with a history of more than 100 years: it began to be used as early as 1884. The drug has an antiseptic effect, mainly in the urinary tract. It is used in its pure form and as part of combined medications (for example, Calcex). In its pure form, hexamethylenetetramine is used orally or intravenously, in the form of salts: hippurate, indigo carmate or camphorate. The mechanism of action is based on the release of free formaldehyde, which denatures bacterial proteins. This determines the tissue specificity of the action of hexamethylenetetramine and the relative safety of the drug, since it breaks down with the release of active formaldehyde only in the acidic environment of urine, thereby acting directly on bacteria that cause diseases of the urinary tract, as well as in inflammatory foci rich in acidic tissue breakdown products. The effect of the drug is dose-dependent.

Nutritional supplements

It is registered in the food industry as a preservative additive (code E239). Often used in cheese making, as well as for preserving caviar. . In Russia, until August 1, 2008, it was listed among “food additives that do not have a harmful effect on human health when used for the manufacture of food products,” but since July 1, 2010, it has been banned. It has a sweetish taste.

At home

Sold in packs of ten tablets of 10 grams each, or 5 tablets of 16 grams under the trade names “Dry fuel”, “Dry alcohol”, “Razzhigaika”. It is used as fuel for cooking (heating) food, for lighting and calcining stoves, heating cellars, garages, etc. (Metaldehyde can also be used as “dry alcohol”).

To impart moisture resistance, it is plasticized with solid petroleum paraffins.

Other Applications

in analytical chemistry, as a component of buffer solutions, etc.
in the production of explosives (raw materials for the production of hexogen) and hexamethylene triperoxide diamine
as a corrosion inhibitor

Safety

Hexamine can be absorbed by the skin from solutions, and in some people it causes skin irritation resembling an allergy.

Notes

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Synonyms

See what "Hexamethylenetetramine" is in other dictionaries: Hexamethylenetetramine...

Spelling dictionary-reference book - (hexamine urotropine), C6H12N4, colorless crystals of sweet taste; sublimes in a vacuum above 230.C, chars at 280.C. Hardener for phenol-formaldehyde resins, raw material for the synthesis of explosives (octogen, hexogen), smokeless solid...

Big Encyclopedic Dictionary Exist., number of synonyms: 3 hexamine (5) hmt (1) methenamine (3) ASIS Dictionary of Synonyms ...

Synonym dictionary HEXAMETHYLENETETRAMINE - Hexamethylentetraminum. Synonyms: methenamine, aminoform, hexamine, formin, formin. Obtained by the interaction of ammonia and formaldehyde. Properties. Colorless crystals or odorless white crystalline powder. Easily soluble in water (1:1.5) ...

Domestic veterinary drugs - (hexamine, urotropine), colorless crystals of sweet taste; sublimes in a vacuum above 230ºC, chars at 280ºC. Hardener for phenol-formaldehyde resins, raw material for the synthesis of explosives (octogen, hexogen), solid smokeless fuel (the so-called... ...

encyclopedic Dictionary Hexamine, colorless crystals; OK. 230 °C sublimes with decomposition. Hardener in the production of phenolic plastics, raw materials for the synthesis of explosives (RDX), antiseptic. means. Hexamethylenetetramine...

Big Encyclopedic Polytechnic Dictionary hexamethylenetetramine - heksametilentetraminas statusas T sritis chemija formulė (CH₂)₆N₄ atitikmenys: angl. hexamethylenetetramine; hexamine; urotropine rus. hexamethylenetetramine; urotropine ryšiai: sinonimas – urotropinas sinonimas – 1,3,5,7 tetraazotriciklo… …

Hexamine, urotropine, colorless crystals with a sweetish taste, charred at 280 °C; above 230 °C sublimes in a vacuum. G. is highly soluble in water, carbon disulfide, moderately in alcohol, chloroform; bad in ether, benzene. They get G.... ... Great Soviet Encyclopedia

See Oxymethylene and Urotropin... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

- (urotropine, hexamine, urizol, methenamine), mol. m. 140.19; colorless crystals, rhombohedral lattice (a = 0.702 nm); bond length SChN 0.146 nm, SChN 0.117 nm; ... Chemical encyclopedia

Physicochemical characteristics Hexamethylenetetramine is a product of the reaction of a solution of formaldehyde with ammonia. It was first received by A.M. Butlerov (1860), but only 35 years after its discovery it began to be used in medicine.

Hexamethylenetetramine is a monoacid base, the tertiary nitrogen gives it basic properties, so with acids it forms double salts, for example hexamethylenetetramine hydrochloride. The presence of tertiary nitrogen, as in alkaloids, also causes the formation of picrates (yellow precipitate), tetraiodides (CH2) β-14 and other reaction products. Hexamethylenetetramine has the ability to form complex compounds with silver, calcium and phosgene salts.

Methods of analysis of urotropine

Identify Hexamethylenetetramine in an acidic environment decomposes with the release of formaldehyde. When an alkali solution is added to the reaction mixture, the smell of ammonia is felt.

The quantitative content of the drug can be determined by the neutralization method. A sample of the drug is heated with a certain amount of a titrated solution of sulfuric acid; after cooling the mixture, the excess acid is titrated with alkali against methyl red. In parallel, a control experiment (pharmacopoeial method) is carried out under the same conditions.

5 ml of a 10% solution is placed in a 50 ml volumetric flask and the volume of the solution is adjusted to the mark with water. To 2 ml of the diluted solution add 2 ml of water, 2 drops of methyl orange solution, 1 drop of methylene blue solution and titrate with 0.1 N. with a solution of hydrochloric acid until violet coloration.

1 ml 0.1 n. hydrochloric acid solution corresponds to 0.0140 g of hexamethylenetetramine.

To analyze a 2% solution, take 1 ml of hexamethylenetetramine solution, add 2 drops of methyl orange solution, 1 drop of methylene blue solution and titrate with 0.1 N. with a solution of hydrochloric acid until violet coloration.

The quantitative content of hexamethylenetetramine (x,%) in a 10% solution is calculated using the formula:

A - volume of hexamethylenetetramine solution taken for determination, ml (5 ml);

V1- volume of the drug solution after the first dilution, ml (50 ml);

V2- volume of an aliquot of the dilution taken for titration, ml (2 ml);

V- volume of titrant (HCl) used for titration;

TO - correction factor to the concentration of the titrant solution;

T - titrant titer for the substance being determined.

Hexamine (Hexamine, Hexamethylenetetramine, Methenamine, food additive E239, dry fuel, dry alcohol)– a synthetic drug, antibacterial drug, component in the production of plastics and synthetic rubber.

Physicochemical characteristics.

Chemical formula: C 6 H 12 N 4. Appearance - colorless rhombic crystals, odorless. Density: 1.27 g/cm3. Melting point 263°C. Decomposition temperature 280°C. When heated, it evaporates without melting. Burns with a pale flame. Aqueous solutions have an alkaline reaction. In an acidic environment it breaks down, releasing formaldehyde. Heat of combustion 30.045 MJ/kg.

Solubility of methenamine in various solvents

Solvent	Temperature, °C	Solubility, g/100g solvent
Ethanol	12	3,2
Ethanol	20	2,89
Methanol	20	7,25
Acetone	20	0,65
Benzene	20	0,23
Amyl alcohol	20	1,84
Ammonia liquid	20	1,3
Glycerol	20	20,5
Diethyl ether	20	0,06
Xylene	20	0,14
Petroleum ether		Insoluble
Carbon disulfide	20	0,17
Carbon tetrachloride	20	0,85
Trichlorethylene	20	0,11
Chloroform	20	13,4
Water	12	81,3
Water	20	167

Application.

Hexamine is used for growing yeast stock cultures. There should be no residue of it in the finished yeast.
Technical methenamine is used in the production of plastics, synthetic rubber, varnish films; in analytical chemistry for the preparation of buffer solutions, for microcrystalscopic discovery of a number of ions; in the production of explosives (raw materials for the production of hexogen) and hexamethylene triperoxide diamine; as a corrosion inhibitor.
It is used in medicine as a medicine (antiseptic) for the treatment of the urinary tract and as an anti-influenza agent.
In the food industry, hexamethylenetetramine is used as a preservative additive E239. It is used in cheese making, as well as for preserving red caviar.
In everyday life it is used as a dry fuel (“dry alcohol”) for cooking (warming) food, for lighting and calcining stoves, warming cellars, garages, etc.

The use of methenamine as a corrosion inhibitor when cleaning thermal power equipment.

To chemically remove iron oxide deposits from carbon steels in heat exchangers, various complex inhibitors are used, which include methenamine.

Simultaneous cleaning of the inner surface from iron oxides and degreasing is carried out with an aqueous solution: 0.5% hexamine; 0.5% PB-5 inhibitor; 0.3% OP-7. This solution protects steel at temperatures above 60°C. The rate of dissolution of steel under scale (at a temperature of 80 °C) is 15 g/m2 *h.

For Steel 20 and static tensile stresses up to 220 MPa, a washing solution of 4% hydrochloric acid with the addition of 0.5% methenamine and 0.5% PB-5 is used.

To clean scale from high-temperature boilers with a significant reduction in hydrogenation of boiler steel, a solution can be used: 3% hydrochloric acid; 1% sulfuric acid; 0.3% catapina; 0.5% methenamine. The temperature of the working solution is 80°C.

Cleaning the surface of heat exchange equipment made of L-62 brass from iron-copper deposits is carried out by washing with a 3% solution of hydrochloric acid containing 0.05% Fe 3+ and Cu 2+ (temperature 60-80 ° C, solution speed 1 m/s ) with the addition of inhibitors: 0.5% PB-5; 0.15% methenamine; 0.96% sodium thiosulfate. The dissolution rate of brass under deposits at a temperature of 80 °C is 13.8 g/m2 *h, and at a temperature of 60 °C it is 6 g/m2 *h.

Metal etching is a preparatory operation before applying paints, protective and decorative films to metal surfaces, as well as before covering them with other metals. The final result of all work depends on the quality of etching.

Pickling allows you to remove contaminants (rust, scale and other corrosion products) from metal parts that are firmly adhered to their surface. The main purpose of etching is to remove corrosion products; in this case, the base metal should not be etched.

In recipes for etching, solutions of acids are used: nitric, sulfuric, hydrochloric, orthophosphoric, acetic. To prevent metal etching, special additives are added to the solutions. Urotropine is one of these supplements. Hexamine is characterized by its universal use for all of the above solutions of acids and their combinations. Add 0.5 g of methenamine per 1 liter of acid solution to all etching solutions.

Hexamine is used for preserving a limited number of food products (non-consumer products). This is due to the danger of methenamine for human health. In particular, for the preservation of fish caviar, methenamine is used in concentrations of up to 1000 mg/kg of product.

Hexamine contains formaldehyde, which is its active principle. When hexamine is reformed, formaldehyde is split off. Formaldehyde is a strong disinfectant. It is not recommended as a food additive by the Joint FAO/WHO Committee on Food Additives. Formaldehyde actively interacts with proteins and forms difficult-to-cleave protease complexes with them. In this case, the proteins harden. This phenomenon is used when storing histological preparations.

The use of technical methenamine to obtain a pharmacopoeial drug.

Currently, the pharmaceutical industry does not produce hexamine, but is only engaged in the purification of technical hexamine to pharmacopoeial requirements, i.e., purification from impurities of iron oxides, resinous substances and other amines that cause the specific herring odor of aqueous solutions, which should be absent in injectable preparations.

To do this, prepare a 40% solution of technical hexamine in distilled water, add activated carbon until the solution becomes clear and ammonia until the phenolphthalein paper reacts slightly alkaline. After stirring for an hour, the solution is filtered and evaporated in vacuum (700 mmHg, 45°C). The evaporated mass of crystals is again filtered and centrifuged. The crystals are washed with distilled water and dried in a thin layer in a vacuum at a temperature of 45°C, to a moisture content of 1%. The direct yield of dry hexamine (excluding regeneration from the mother liquor) is 40%. Crystals from the mother liquor are purified from the odor of free amines and paraform impurities (paraform causes turbidity in aqueous solutions) by recrystallization from alcohol or washing the crystals in alcohol and subsequent supercentrifugation.

Receipt.

Urizol is produced by the method of contact transformation of methanol into formaldehyde, which reacts with ammonia in the liquid phase to form hexamine crystals, followed by its isolation by precipitation and centrifugation, drying and stabilization with silicon dioxide.

Hexamethylenetetramine quantitative determination. Hexamethylenetetramine (Urotropin)