Натрий сульфит химические свойства, назначение, производство
Химические свойства
Sodium sulfite,Na2S03, is a white,water-soluble, crystalline solid with a sulfurous, salty taste. It decomposes when heated. Sodium sulfite is used as a source of sulfite,as a chemical intermediate and food preservative, in medicine and paper manufacturing, in photographic developing, and as a bleaching agent in the textile industry. Most boiler operators use sodium sulfite for chemicals cavenging of oxygen in the feedwater. Because it decomposes into acidic gases at the high temperatures that accompany high pressures, sodium sulfite should not be used for this purpose at pressures above 122atm (12.4MPa,or 1.8 ksi).
Использование
sodium sulfite has anti-septic, preservative, and anti-oxidant properties. Sodium sulfite is also a topical anti-fungal.
Определение
ChEBI: An inorganic sodium salt having sulfite as the counterion.
Методы производства
Sodium bisulfite is prepared by reacting sulfur dioxide gas with
sodium hydroxide solution. The solid material is obtained by
evaporation of water. Further neutralization with sodium hydroxide
while keeping the temperature above 33.6°C leads to crystallization
of the anhydrous sodium sulfite (below this temperature the
heptahydrate form is obtained).
Общее описание
White odorless powder. Density 2.633 g / cm3. Moderately toxic. Sinks in water and dissolves slowly. Also transported as a heptahydrate Na2SO3.7H2O.
Реакции воздуха и воды
Soluble in water. Reacts with hot water, steam or acids to produce corrosive material.
Профиль реактивности
Sodium sulfite is a reducing agent, particularly under basic conditions. Reacts with oxidizing agents such as peroxides, epoxides, oxoacids. Emits toxic fumes of sodium oxide and oxides of sulfur if heated to decomposition [Lewis, 3rd ed., 1993, p. 1174].
Опасность
Use prohibited in meats and other sources
of Vitamin B
1
Угроза здоровью
When ingested, solutions cause gastric irritation by the liberation of sulfurous acid. Because of rapid oxidation to sulfate, sulfites are well tolerated until large doses are reached; then violent colic and diarrhea, circulatory disturbances, central nervous depression, and death can occur.
Пожароопасность
Literature sources indicate that Sodium sulfite is noncombustible.
Фармацевтические приложения
Sodium sulfite is used as an antioxidant in applications similar to
those for sodium metabisulfite. It is also an effective antimicrobial
preservative, particularly against fungi at low pH (0.1% w/v of
sodium sulfite is used). Sodium sulfite is used in cosmetics, food
products, and pharmaceutical applications such as parenteral
formulations, inhalations, oral formulations, and topical preparations.
Контактные аллергены
Sodium sulfite is mainly used in photographic developers, for fixing prints, bleaching textile fibers, as a reducer in manufacturing dyes, as a remover of Cl in bleached textiles and paper, and as a preservative in the food industry for meat, egg yolks, and so on.
Профиль безопасности
Poison by intravenous and subcutaneous routes. Moderately toxic by ingestion and intraperitoneal routes. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Na2O and SOx. A reducing agent. See also SULFITES.
Безопасность
Sodium sulfite is widely used in food and pharmaceutical
applications as an antioxidant. It is generally regarded as relatively
nontoxic and nonirritant when used as an excipient. However,
contact dermatitis and hypersensitivity reactions have been
reported. The acceptable daily intake for sodium sulfite has
been set at up to 350 mg/kg body-weight daily.
LD50 (mouse, IP): 0.950 g/kg
LD50 (mouse, IV): 0.130 g/kg
LD50 (mouse, oral): 0.820 g/kg
LD50 (rabbit, IV): 0.065 g/kg
LD50 (rabbit, oral): 1.181 g/kg
LD50 (rat, IV): 0.115 g/kg
Возможный контакт
Sodium sulfite is used as a reducing agent; in boiler water treatment; food applications; in photographic developers and fixers; in bleaching of wool, paper, textiles, straw and silk; manufacture of dyes; dechlorination; preservation of meat, fruit and egg products; silvering of glass.
Экологическая судьба
Because sodium sulfite is a solid powder that is generally sold
as a ‘food grade’ substance, there is very little information
available on the environmental fate of sodium sulfite. It has
a molecular weight of 126.04 g mol-1. At 20°C, the solubility
in water is 250 000 mg l-1, and as it is an inorganic salt the
vapor is negligible (USEPA, 2011). The log octanol/water
partition coefficient is estimated to be 7.78.
If released into water or soil, sodium sulfite would most
likely be oxidized to sulfate, which would then be available for
use by bacteria or plants as a nutrient.
The US Environmental Protection Agency (EPA) EPI Suite
computer program (USEPA, 2011) estimates both a bioconcentration
factor and a bioaccumulation factor of 0.89. These
factors are less than one, meaning that bioconcentration and/or
bioaccumulation of sodium sulfite would be virtually negligible
and therefore would not cause any adverse effects to fish and
wildlife.
хранилище
Sodium sulfite should be stored in a well-closed container in a cool,
dry, place. In solution, sodium sulfite is slowly oxidized to sulfate by dissolved oxygen; strong acids lead to formation of sulfurous acid/
sulfur dioxide. On heating, sodium sulfite decomposes liberating
sulfur oxides.
Перевозки
UN3260 Corrosive solid, acidic, inorganic, n.o.s., Hazard class: 8; Labels: 8-Corrosive material.
Методы очистки
Crystallise the sulfite from warm water (0.5mL/g) by cooling to 0o. Also purify it by repeated crystallisation from deoxygenated water inside a glove-box, and finally drying it under vacuum. [Rhee & Dasgupta J Phys Chem 89 1799 1985.]
Несовместимости
Sodium sulfite is incompatible with acids, oxidizing agents, many
proteins, and vitamin B1.
Регуляторный статус
GRAS listed. Accepted for use as a food additive in Europe.
Included in FDA Inactive Ingredients Database (epidural, IM, IV,
and SC injections; inhalation solution; ophthalmic solutions; oral
syrups and suspensions; otic solutions; topical creams and emulsions).
Included in nonparenteral medicines licensed in the UK.
Натрий сульфит препаратная продукция и сырье
сырьё
препарат