In medical practice in the form of an injection solution as a detoxifying and desensitizing agent or externally as an insecticidal agent, in veterinary medicine as a remedy against skin diseases, in the pharmaceutical industry in the production of medicines; for the preparation of solutions of sodium thiosulfate 30% for injection.

Sodium thiosulfate is also used

• for removing traces of chlorine after bleaching fabrics
• for extracting silver from ores;
• fixer in photography;
• reagent in iodometry
• antidote for poisoning: As, Br, Hg and other heavy metals, cyanides (converts them into thiocyanates), etc.
• for intestinal disinfection;
• for the treatment of scabies (together with hydrochloric acid);
• anti-inflammatory and anti-burn agent;
• can be used as a medium for determining molecular weights by lowering the freezing point (cryoscopic constant 4.26°)
• in the food industry it is registered as a food additive E539.
• additives for concrete.
• for cleansing tissues of iodine

Description

Physicochemical characteristics

Colorless, transparent, odorless crystals

Packing

Bag 40 kg. Package 1 kg. Bag 35 kg. Bag 0.5 kg. 1 kg bag. 5 kg bag. Bag 10 kg.

Storage

Packaging: 0.5 kg each; 1 kg; 5 kg; 10 kg; 35 kg; 40 kg; 45 kg in bags or bags made of polyethylene film or packaging paper with a polymer coating.

Storage: In a dry place, in well-packed containers. Shelf life - 5 years.

Pharmacopoeial sodium thiosulfate produced by the Chemical Plant named after. L.Ya. Karpova

Mass fraction, %		Norm
Na 2 S 2 O 3 *5H 2 O		99,0-102,0
calcium		no reaction
sulfides		you stand the test
sulfites and sulfates	Max.	0,01
chlorides	Max.	0,005
heavy metals	Max.	0,001
arsenic, selenium		no reaction
gland	Max.	0,002
alkalinity		absence of pink coloration of phenolphthalein
Microbiological purity		corresponds to the State Fund XI issue 2, p. 193

• Product Code: 264-01
• Availability: In stock

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Sodium thiosulfate (antichlor, hyposulfite, sodium sulfidetrioxosulfate) - Na 2 S 2 O 3 or Na 2 SO 3 S, sodium salt and thiosulfuric acid. Under normal conditions, it exists in the form of Na 2 S 2 O 3 ·5H 2 O pentahydrate.

Colorless monoclinic crystals.

Molar mass 248.17 g/mol.

Soluble in water (41.2% at 20 o C, 69.86% at 80 o C).

At 48.5 °C it melts in its water of crystallization and dehydrates at about 100 °C.

When heated to 220 °C, it decomposes according to the following scheme:

4Na 2 S 2 O 3 →(t) 3Na 2 SO 4 + Na 2 S 5

Na 2 S 5 →(t) Na 2 S + 4S

Sodium thiosulfate is a strong reducing agent:

Strong oxidizing agents, for example, free chlorine, are oxidized to sulfate or sulfuric acid:

Na 2 S 2 O 3 + 4Cl 2 + 5H 2 O → 2H 2 SO 4 + 2NaCl + 6HCl.

With weaker or slow-acting oxidizing agents, for example, iodine, it is converted into salts of tetrathionic acid:

2Na 2 S 2 O 3 + I 2 → 2NaI + Na 2 S 4 O 6.

The above reaction is very important, as it serves as the basis for iodometry. It should be noted that in an alkaline environment, the oxidation of sodium thiosulfate with iodine can proceed to sulfate.

It is impossible to isolate thiosulfuric acid (hydrogen thiosulfate) by the reaction of sodium thiosulfate with a strong acid, since it is unstable and immediately decomposes:

Na 2 S 2 O 3 + H 2 SO 4 → Na 2 SO 4 + H 2 S 2 O 3

H 2 S 2 O 3 → H 2 SO 3 + S

Molten sodium thiosulfate is very prone to hypothermia.

1. Receipt.

oxidation of Na polysulfides;

boiling excess sulfur with Na 2 SO 3:

S + Na 2 SO 3 →(t) Na 2 S 2 O 3 ;

interaction of H 2 S and SO 2 with NaOH by-product in the production of NaHSO 3, sulfur dyes, when purifying industrial gases from S:

4SO 2 + 2H 2 S + 6NaOH → 3Na 2 S 2 O 3 + 5H 2 O;

boiling excess sulfur with sodium hydroxide:

3S + 6NaOH → 2Na2S + Na2SO3 + 3H2O

Then, in the above reaction, sodium sulfite adds sulfur to form sodium thiosulfate.

At the same time, during this reaction, sodium polysulfides are formed (they give the solution a yellow color). To destroy them, SO 2 is passed into the solution.

Pure anhydrous sodium thiosulfate can be prepared by reacting sulfur with sodium nitrite in formamide. This reaction proceeds quantitatively (at 80 °C for 30 minutes) according to the equation:

2NaNO 2 + 2S → Na 2 S 2 O 3 + N 2 O

1. Qualitative analysis.

   1. Analytical reactions for sodium cation.

1. Reaction with zinc dioxourane(VI) acetate Zn(UO 2 ) 3 (CH 3 COO) 8 with the formation of a yellow crystalline precipitate (pharmacopoeial reaction - GF) or yellow crystals of tetrahedral and octahedral shape, insoluble in acetic acid (MCA). To increase the sensitivity of the reaction, the test mixture should be heated on a glass slide.

NaCl+ Zn(UO 2) 3 (CH 3 COO) 8 + CH 3 COOH + 9 H 2 O

NaZn(UO 2) 3 (CH 3 COO) 9 9 H 2 O + HCl

Interfering ions: excess K + ions, heavy metal cations (Hg 2 2+, Hg 2+, Sn 2+, Sb 3+, Bi 3+, Fe 3+, etc.). The reaction is used as a fractional reaction after removing interfering cations.

2. Coloring the colorless burner flame yellow (YF).

3. Reaction with picric acid to form yellow, needle-shaped sodium picrate crystals emanating from one point (ISS).

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The reaction is used as a fractional reaction only in the absence of interfering ions (K +, NH 4 +, Ag +).

4. Reaction with potassium hexahydroxostibate(V) K with the formation of a white crystalline precipitate, soluble in alkalis.

NaCl+K
Na + KCl

Conditions for the reaction: a) sufficient concentration of Na +; b) neutral reaction of the solution; c) carrying out the reaction in the cold; d) rubbing a glass rod against the wall of the test tube. Interfering ions: NH 4 +, Mg 2+, etc.

In an acidic environment, the reagent is destroyed with the formation of a white amorphous precipitate of metaantimony acid HSbO 3.

K+HCl
KCl + H 3 SbO 4 + 2 H 2 O

H3SbO4
HSbO 3  + H 2 O

Sodium thiosulfate is a synthetic compound known in chemistry as sodium sulfate, and in the food industry as additive E539, approved for use in food production.

Sodium thiosulfate functions as an acidity regulator (antioxidant), anti-caking agent or preservative. The use of thiosulfate as a food additive allows you to increase shelf life and product quality, and prevent rotting, souring, and fermentation. In its pure form, this substance is involved in technological processes for the production of edible iodized salt as an iodine stabilizer and is used for processing baking flour, which is prone to caking and clumping.

The use of the food additive E539 is limited exclusively to the industrial sphere; the substance is not available for retail sale. For medical purposes, sodium thiosulfate is used as an antidote for severe poisoning and an anti-inflammatory agent for external use.

general information

Thiosulfate (hyposulfite) is an inorganic compound that is the sodium salt of thiosulfuric acid. The substance is a colorless, odorless powder, which upon closer examination turns out to be transparent monoclinic crystals.

Hyposulfite is an unstable compound that does not occur in nature. The substance forms a crystalline hydrate, which, when heated above 40 °C, melts in its own crystalline water and dissolves. Molten sodium thiosulfate is prone to supercooling, and at a temperature of about 220 ° C the compound is completely destroyed.

Sodium thiosulfate: synthesis

Sodium sulfate was first obtained artificially in the laboratory using the Leblanc method. This compound is a byproduct of soda production, which is formed by the oxidation of calcium sulfide. Interacting with oxygen, calcium sulfide is partially oxidized to thiosulfate, from which Na 2 S 2 O 3 is obtained using sodium sulfate.

Modern chemistry offers several methods for the synthesis of sodium sulfate:

• oxidation of sodium sulfides;
• boiling sulfur with sodium sulfite;
• interaction of hydrogen sulfide and sulfur oxide with sodium hydroxide;
• boiling sulfur with sodium hydroxide.

The above methods can produce sodium thiosulfate as a by-product of the reaction or in the form of an aqueous solution from which the liquid must be evaporated. An alkaline solution of sodium sulphate can be obtained by dissolving its sulfide in oxygenated water.

The pure anhydrous compound thiosulfate is the result of the reaction of a sodium salt and nitrous acid with sulfur in a substance known as formamide. The synthesis reaction occurs at a temperature of 80 °C and lasts about half an hour; its products are thiosulfate and its oxide.

In all chemical reactions, hyposulfite acts as a strong reducing agent. In reactions with strong oxidizing agents, Na 2 S 2 O 3 is oxidized to sulfate or sulfuric acid, and with weak ones - to tetrathione salt. The oxidation reaction of thiosulfate is the basis of the iodometric method for determining substances.

The interaction of sodium thiosulfate with free chlorine, which is a strong oxidizing agent and toxic substance, deserves special attention. Hyposulfite is easily oxidized by chlorine and converts it into harmless water-soluble compounds. Thus, this compound prevents the destructive and toxic effects of chlorine.

In industrial conditions, thiosulfate is extracted from gas production waste. The most common raw material is illuminating gas, which is released during the coking process of coal and contains hydrogen sulfide impurities. Calcium sulfide is synthesized from it, which is subjected to hydrolysis and oxidation, after which it is combined with sodium sulfate to produce thiosulfate. Despite the multi-stage process, this method is considered the most cost-effective and environmentally friendly method for extracting hyposulfite.

What you need to know about sodium thiosulfate

Systematic name	Sodium thiosulfate
Traditional names	Sodium disulfide, sodium hyposulfite (sodium) soda, antichlorine
International marking	E539
Chemical formula	Na2S2O3
Group	Inorganic thiosulfates (salts)
State of aggregation	Colorless monoclinic crystals (powder)
Solubility	Soluble in, insoluble in
Melting temperature	50 °C
Critical temperature	220 °C
Properties	Reductive (antioxidative), complexing
Dietary Supplement Category	Acidity regulators, anti-caking agents (anti-caking agents)
Origin	Synthetic
Toxicity	Not studied, the substance is conditionally safe
Areas of use	Food, textile, leather industry, photography, pharmaceuticals, analytical chemistry

Sodium thiosulfate: application

Sodium disulfide was used for a variety of purposes long before the compound was included in food supplements and medications. Antichlorine was used to impregnate gauze bandages and gas mask filters to protect the respiratory system from toxic chlorine during the First World War.

Modern areas of application of hyposulfite in industry:

• processing photographic film and recording images on photographic paper;
• dechlorination and bacteriological analysis of drinking water;
• removal of chlorine stains when bleaching fabrics;
• gold ore leaching;
• production of copper alloys and patina;
• leather tanning.

Sodium sulfate is used as a reagent in analytical and organic chemistry; it neutralizes strong acids and neutralizes heavy metals and their toxic compounds. The reactions of thiosulfate with various substances are the basis of iodometry and bromometry.

Food additive E539

Sodium thiosulfate is not a widely used food additive and is not freely available due to the instability of the compound and the toxicity of its breakdown products. Hyposulfite is involved in technological processes for the production of edible iodized salt and bakery products as an acidity regulator and anti-caking agent.

Additive E539 functions as an antioxidant and preservative in the production of canned vegetables and fish, desserts and alcoholic beverages. This substance is also part of the chemicals used to treat the surface of fresh, dried and frozen vegetables and fruits.

Preservative and antioxidant E539 is used to improve the quality and increase the shelf life of such products:

• fresh and frozen vegetables, fruits, seafood;
• , nuts, seeds;
• vegetables, mushrooms and seaweed, canned in or oil;
• jams, jellies, candied fruits, fruit purees and fillings;
• fresh, frozen, smoked and dried fish, seafood, canned food;
• flour, starches, sauces, seasonings, vinegar, ;
• white and cane, sweeteners (dextrose and), sugar syrups;
• fruit and vegetable juices, sweet water, low-alcohol drinks, grape drinks.

When producing table iodized salt, the food additive E539 is used to stabilize iodine, which can significantly extend the shelf life of the product and preserve its nutritional value. The maximum permissible concentration of E539 in table salt is 250 mg per 1 kg.

In baking, sodium thiosulfate is actively used as part of various additives to improve product quality. Baking improvers are either oxidative or reductive. Anti-caking agent E539 is a restorative improver that allows you to change the properties.

Dough made from dense flour with short-tearing gluten is difficult to process, cakes, does not reach the required volume and cracks during baking. Anti-caking agent E539 destroys disulfide bonds and structures gluten proteins, as a result of which the dough rises well, the crumb becomes loose and elastic, and the crust does not crack during baking.

At enterprises, an anti-caking agent is added to flour along with yeast immediately before kneading the dough. The thiosulfate content in flour is 0.001-0.002% of its mass, depending on the manufacturing technology of the bakery product. Sanitary standards for the E539 additive are 50 mg per 1 kg of wheat flour.

Anti-caking agent E539 is used in technological processes in strict dosages, so there is no risk of thiosulfate poisoning when consuming flour products. Flour intended for retail sale is not processed before sale. Within normal limits, the supplement is safe and does not have a toxic effect on the body.

Use in medicine and its effect on the body

Soda hyposulfite is included in the World Health Organization's list of essential medicines as one of the most effective and safe medicines. It is administered subcutaneously, intramuscularly and intravenously as an injection solution or used as an external agent.

At the beginning of the twentieth century, sodium thiosulfate was first used as an antidote for hydrocyanic acid poisoning. In combination with sodium nitrite, thiosulfate is recommended for particularly severe cases of cyanide poisoning and is administered intravenously to convert the cyanide into non-toxic thiocyanates, which can then be safely excreted from the body.

Medical uses of sodium sulfate:

The effect of hyposulfite on the human body when consumed orally has not been studied, so it is impossible to judge the benefits and harms of the substance in its pure form or as part of food products. There have been no cases of poisoning with the E539 additive, so it is generally considered non-toxic.

Sodium thiosulfate and legislation

Sodium thiosulfate is included in the list of food additives approved for use in food production in Russia and Ukraine. Anti-caking agent and acidity regulator E539 are used in accordance with established sanitary and hygienic standards exclusively for industrial purposes.

Due to the fact that the effect of the chemical on the human body when administered orally has not yet been studied, the E539 additive is not approved for use in the EU and the USA.

DEFINITION

Sodium thiosulfate under normal conditions it is colorless monoclinic crystals (Fig. 1), relatively well soluble in water (41.2% at 20 o C, 69.86% at 80 o C).

Forms crystalline hydrates of the composition Na 2 S 2 O 3 × 5H 2 O, which in the molten state are prone to supercooling. When heated to a temperature of 220 o C, it decomposes. In OVR it exhibits strong restorative properties.

Rice. 1. Sodium thiosulfate. Appearance.

Chemical formula of sodium thiosulfate

The chemical formula of sodium thiosulfate is Na 2 S 2 O 3. It shows that this molecule contains two sodium atoms (Ar = 23 amu), two sulfur atoms (Ar = 32 amu) and three oxygen atoms (Ar = 16 amu. m.). Using the chemical formula, you can calculate the molecular weight of sodium thiosulfate:

Mr(Na 2 S 2 O 3) = 2×Ar(Na) + 2×Ar(S) + 3×Ar(O);

Mr(Na 2 S 2 O 3) = 2×23 + 2×32 + 3×16 = 46 + 64 + 48 = 158.

Graphic (structural) formula of sodium thiosulfate

The structural (graphic) formula of sodium thiosulfate is more clear. It shows how atoms are connected to each other inside a molecule:

Ionic formula

Sodium thiosulfate is an electrolyte that dissociates into ions in aqueous solution according to the following reaction equation:

Na 2 S 2 O 3 ↔ 2Na + + S 2 O 3 2- .

Examples of problem solving

EXAMPLE 1

Exercise	Find the chemical formula of a substance that contains 10 parts by mass of calcium, 7 parts by mass of nitrogen and 24 parts by mass of oxygen.
Solution	Let's find the molar masses of calcium, nitrogen and oxygen (we'll round the values ​​of the relative atomic masses taken from D.I. Mendeleev's Periodic Table to whole numbers). It is known that M = Mr, which means M(Ca) = 40 g/mol, M(N) = 14 g/mol, and M(O) = 16 g/mol. n (Ca) = m (Ca) / M (Ca); n(Ca) = 10 / 40 = 0.25 mol. n(N) = m(N)/M(N); n(N) = 7 / 14 = 0.5 mol. n(O) = m(O)/M(O); n(O) = 24 / 16 = 1.5 mol. Let's find the molar ratio: n(Ca) :n(N): n(O) = 0.25: 0.5: 1.5= 1: 2: 6, those. the formula for the compound of calcium, nitrogen and oxygen is CaN 2 O 6 or Ca(NO 3) 2. This is calcium nitrate.
Answer	Ca(NO3)2

EXAMPLE 2

Exercise	Calcium phosphide weighing 3.62 g contains 2.4 g of calcium. Determine the formula of this compound.
Solution	In order to find out in what relationships the chemical elements in the molecule are located, it is necessary to find their amount of substance. It is known that to find the amount of a substance one should use the formula: Let's find the molar masses of calcium and phosphorus (the values ​​of the relative atomic masses taken from D.I. Mendeleev's Periodic Table are rounded to whole numbers). It is known that M = Mr, which means M(Ca) = 40 g/mol, and M(P) = 31 g/mol. Let us determine the mass of phosphorus in the composition of calcium phosphide: m(P) = m (Ca x P y) - m(Ca); m(P) = 3.62 - 2.4 = 1.22 g. Then, the amount of substance of these elements is equal to: n (Ca) = m (Ca) / M (Ca); n(Ca) = 2.4 / 40 = 0.06 mol. n(P) = m(P)/M(P); n(P) = 1.22/31 = 0.04 mol. Let's find the molar ratio: n(Ca) :n(P)= 0.06: 0.04 = 1.5: 1 = 3: 2, those. the formula of calcium phosphide is Ca 3 P 2.
Answer	Ca 3 P 2

Medicines elements VI And IV groups of the periodic table of elements.

ANALYSIS OF SULFUR COMPOUNDS. 6 GROUP PSE.

Sulfur in the human body is found in the epidermis, skin, muscles, pancreas, and hair. It is part of some amino acids (methionine, cysteine), peptides that participate in the processes of tissue respiration and catalyze enzymatic processes.

In medicine, sulfur itself is used in the form of ointments and sodium thiosulfate.

Sodium thiosulfate Natrii thiosulfas (ln)

Na 2 S 2 O 3 5 H 2 OSodiumthiosulfate (MHH)

Sodium salt of thiosulfuric acid

Structural formula:

Sulfur atoms have different oxidation states. Due to S 2 - LB exhibit restorative properties.

Receipt

When heating sodium sulfite and sulfur ( was first obtained in 1799):

Na 2 SO 3 +S→Na 2 S 2 O 3

Oxidation of sodium sulfide with sulfur dioxide:

2Na 2 S+ 3S0 2 → 2Na 2 S 2 0 3 +S↓

Currently it is obtained using gas production waste containing hydrogen sulfide. The method, despite its multi-stage nature, is economically beneficial:

Hydrogen sulfide is captured by an absorber - calcium hydroxide:

Ca(OH) 2 + H 2 S → CaS + 2H 2 S

however, due to the hydrolysis of calcium sulfide, the following reactions occur:

CaS + 2H 2 O → Ca(OH) 2 + H 2 S

2Ca(OH) 2 + 3H 2 S → CaS + Ca(SH) 2 + 4H 2 O

Calcium hydrosulfide is oxidized by atmospheric oxygen to calcium thiosulfate:

Ca(SH) 2 + 2O 2 → CaS 2 O 3 + H 2 O

calcium thiosulfate is fused with calcium carbonate:

CaS 2 O 3 + Na 2 CO 3 → Na 2 S 2 O 3 + CaCO 3 ↓

Description and solubility

Colorless transparent crystals, odorless. In warm, dry air it loses crystallization water (eroses). In humid air it spreads (turns into a liquid state). At a temperature of +50 0 C it melts in water of crystallization.

Very easily soluble in water, practically insoluble in alcohol.

Chemical properties

As can be seen from the formula, the oxidation state of sulfur is different (6+ and 2-). Having S 2- in the molecule, the drug exhibits restorative properties.

Sodium thiosulfate, like thiosulfuric acid, of which it is a salt, is not a strong compound, easily decompose under the influence of acids, even carbonic (air humidity + carbon dioxide):

Na 2 S 2 O 3 + CO 2 + H 2 O → Na 2 CO 3 + H 2 S 2 O 3

H 2 S 2 O 3 → S↓ + SO 2 + H 2 O

yellow smell

sediment (turbidity)

This property is used in authenticity reactions:

Authenticity

Reactions to sodium ion(see catine anions).

Reactions to thiosulfate ion:

Decomposition reaction with dilute hydrochloric acid when dilute hydrochloric acid is added to a solution of the drug, the solution gradually becomes cloudy - free sulfur is released (unlike salts of sulfurous acid), then the specific smell of sulfur dioxide SO 2 appears:

Na 2 S 2 O 3 + 2HCl → 2NaCl + SO 2 + S↓+ H 2 O

smell yellow

sediment (turbidity)

S 2 O 3 2- + H 2 O - 2ē → 2SO 2 + 2H +

S 2 O 3 2- + 6H + + 4ē → 2S↓ + 3H 2 O

Reaction with silver nitrate solution.

When an excess of silver nitrate is added, a white precipitate is released, which quickly turns yellow, when standing it turns brown and finally turns black due to the formation of silver sulfide

First, a white precipitate of silver thiosulfate is formed:

Na 2 S 2 O 3 + 2AgN0 3 → Ag 2 S 2 O 3 ↓ + 2NaN0 3

Silver thiosulfate quickly decomposes (intramolecular redox reaction), silver sulfite and sulfur are formed (yellow precipitate):

Ag 2 S 2 O 3 → Ag 2 SO 3 ↓ + S↓

When standing, a black precipitate of silver sulfide is formed:

Ag 2 SO 3 + S + H 2 O → Ag 2 S↓ + H 2 SO 4

If the reaction procedure is changed - adding sodium thiosulfate to a solution of silver nitrate, then the white precipitate of silver thiosulfate dissolves in excess sodium thiosulfate:

Ag 2 S 2 O 3 + 3Na 2 S 2 O 3 → 2Na 3