1 Physical and Chemical Properties
Physical Properties: colorless transparent sodium thiosulfate
Monoclinic crystals , soluble in water , insoluble in alcohol . Pentahydrate temperature 48 degrees Celsius, the melt in the melting of crystal water .
Chemical properties: heat decomposition, decomposed into sodium and sulfur or sodium sulfate and sodium polysulfide , while being oxidized by oxygen . In case of acid decomposition of sodium thiosulfate emit sulfur dioxide gas and sulfur precipitation . Heating in air oxidation and decomposition into sodium , sulfur dioxide and water. Combustion generated sulfate, sodium sulfide and sulfur in the absence of air .
2 Determination
Method name: Sodium thiosulfate – Determination of sodium thiosulfate – Redox Titration
Application: This method uses sodium thiosulfate determination of redox titration. This method applies to the determination of sodium thiosulfate .
Method: Take the test amount , add water to dissolve , add starch indicator solution with iodine solution was titrated droplet to continuous blue. Each 1mL iodine titration solution (0.05mol / L) is equivalent to 15.81mg of Na2S2O3. Computing , that is.
Reagents:
1 water ( boiling placed to room temperature )
2 . Iodine titration solution (0.05mol / L)
3 sodium hydroxide solution (1mol / L)
4 methyl orange indicator solution
5 . Sulfuric acid titration solution (0.5mol / L)
6. Sodium bicarbonate
7 starch indicator solution
8 phenolphthalein indicator solution
9 methyl red – bromocresol green mixed indicator solution
10 benchmark arsenic trioxide
11 Basis of potassium hydrogen phthalate
12 benchmark anhydrous sodium carbonate
3 Uses Introduction
When tanning dichromate reducing agent , nitrogen exhaust neutralizer , mordant , straw and
Hair bleach and bleach pulp dechlorination time . Also for tetraethyl lead , dyes intermediates manufacturing and ore mention silver electroplating industry reductant , water purifying agent works .
In the textile industry for bleaching cotton after dechlorination agent , sulfur dyeing wool fabric dye , indigo dye anti- white agents , pulp dechlorination agent , the pharmaceutical industry as detergents, disinfectants and bleaching agents. [ 1 ] analysis reagents for chromatography reagents , drip Determination of cobalt , photographic fixer , dechlorination agent capacity analysis commonly used reagents, sodium, preparation of injectables and double sugar iron urea medium mordant .
Thiosulfate cyanide can also be used as antidotes .
4 Method
Commonly used industrial sulfur with sodium sulfite and sodium thiosulfate to give boiled , purified by recrystallization : Na2SO3 + S + 5H2O = Na2S2O3 · 5H2O
Sodium sulfite dissolved soda method , and ( combustion of sulfur ) of sulfur dioxide and generated sodium sulfite , sulfur boiling reactor was added , filtered , concentrated and crystallized to obtain sodium thiosulfate .
Na2CO3 + SO2 == Na2SO3 + CO2
Na2SO3 + S +5 H2O == Na2S2O3.5H2O
Evaporation residue method using sodium sulfide , sodium sulfide , sodium carbonate and sodium sulfide sulfur dioxide react with barium sulfide in wastewater emissions of sulfur by sulfur absorption , evaporation, crystallization , obtained sodium thiosulfate .
2Na2S + Na2CO3 +4 SO2 == 3Na2S2O3 + CO2
Oxide , sodium sulfite , and the recrystallization containing sodium sulfide, sodium sulfite and caustic soda liquid sulfur by oxidation ; sodium bisulfite and sulfur crude product by recrystallization three thiosulfate thiosulfate resulting mixture was concentrated , crystallized to obtain sodium thiosulfate .
2Na2S +2 S +3 O2 == 2Na2S2O3
Na2SO3 + S == Na2S2O3
Recrystallization of the crude crystals were dissolved sodium thiosulfate (or the crude solution of sodium thiosulfate ) , after cleaning, concentrated and crystallized to obtain sodium thiosulfate .
5 Considerations
Should be stored in a cool dry place . Transportation should avoid exposure to rain. Not with acids , oxidizers of storage or shipment . Containers must be sealed to prevent moisture dissolves. Such as packaging damp, description of contents has played the role of deliquescence , must be packaged dry stacked separately. Can not be stored in the open air, to seize on the damp package deal . When fighting fire with water sand .
It can be the solution of cyanide poisoning and mercuric chloride poisoning
Acute cyanide poisoning rapid progression of the disease , it should be against the clock to rescue acute poisoning , emphasizing locally applied antidote.
1 , oral poisoning , gastric lavage available 1:2000 potassium permanganate solution and vomiting induced by stimulation of the posterior pharyngeal lavage ;
2 , inhalation poisoning should be immediately evacuated , move to fresh air , well-ventilated place to rest ;
3, with sub- acid amyl nitrate after the crushing 1-2 branched into a handkerchief , nose and mouth before poisoning on inhalation, every two minutes , once every 5-6 times ;
4 , symptomatic treatment. Occur circulation , respiratory failure were given in the arm, vasopressors , respiratory stimulants, oxygen, artificial respiration ; skin burns , potassium permanganate solution, rinse , and then washed with ammonium sulfide solution ;
5 , after the above scene by emergency should be immediately sent to hospital for treatment , must not be delayed.
Nitrite – sodium thiosulfate therapy :
Detoxification mechanisms:
Methemoglobin formation agent such as nitrite can rapidly form of hemoglobin to methemoglobin , which ferric ions and free the body or in combination with cytochrome oxidase cyano combine to form an unstable cyanmethemoglobin , leaving ELISA inhibition . Cyanmethemoglobin in a few minutes can be dissociated cyanide ions , so the need to provide for rapid sulfur agents such as sodium thiosulfate , cyanide ions into the low toxicity of thiocyanate and excreted.
Usage:
Now amyl nitrite having 1 to 2 (0.2 ~ 0.4ml) wrapped in a clean cloth crushed to give 15 to 30 seconds inhalation , can be repeated after 5 minutes , a total of not more than 3 . Children each dose is 1 . After the formation of the pharmaceutical in the body is only a small amount of denatured hemoglobin, it is only as an emergency measure.
3% Sodium nitrite 10 ~ 15ml intravenous injection 2 ~ 3ml per minute. Children give 6 ~ 10mg/kg. These two drugs can lower blood pressure , a circulation disorder with caution .
At the same speed with the same injection needle 25 to 50% sodium thiosulfate 20 ~ 50ml. Children give 0.25 ~ 0.5g/kg. Repeat as necessary after an hour and a half or full amount of the amount of discretion after repeated use . Mild poisoning can be alone with this drug .
Soda is the colorless transparent crystal , easily soluble in water , aqueous solution is alkaline. It weathered the loss of crystal water above 33 ℃ in dry air. Neutral , alkaline solution is stable in the acidic solution will rapidly decompose .
Na2S2O3 +2 HCl = 2NaCl + H2O + S ↓ + SO2 ↑
Soda has a strong complexing ability trophies silver bromide to form complexes . Reaction formula : AgBr +2 Na2S2O3 = NaBr + Na3 [Ag (S2O3) 2], according to this property, it can be used as a fixing agent. Wash phase , with an excess of soda unexposed silver bromide on the film part of the reaction , the conversion of soluble Na3 [Ag (S2O3) 2], the removal of AgBr , the developing part fixed.
Soda also has a strong reduction, chlorine and other substances can be restored.
Na2S2O3 +4 Cl2 +5 H2O = 2H2SO4 +2 NaCl +6 HCl
Therefore, it can be used as a bleaching cotton fabric after dechlorination agent. Similar reasoning , the iodine stains on the fabric can also be used to remove it .
In addition, the soda is also used in leather tanning , electroplating and silver extracted from the ore .
Sweat stain ( tinea versicolor ) radical approach : topical 20% to 30 % sodium thiosulfate solution , topical 1% dilute hydrochloric acid immediately after dry ; or optional 3% Triatop lotion wash the affected area ; usage are daily from 1 to 2 times.
Packing: PVC bag or plastic lined woven bag , net weight 40 kg .
Storage: Store in a cool dry place . Dark, sealed storage, transport should avoid exposure to moisture and rain.