Хлорид натрия

Описание

Sodium chloride is widely distributed in nature. Oceans are the vast source of sodium chloride. It occurs in seawater at an average concentration of 2.68 wt%. It also occurs in many inland saline waters and in salt deposits in sedimentary rocks, as the mineral halite.
Sodium chloride is probably the most important salt of both sodium and chlorine. Sodium chloride, common table salt, is an essential component of most food preparation, imparting flavor to food and providing the sodium nutritional requirement. Also, it is used for preserving food. Therapeutically, NaCl solution is used to combat dehydration as an electrolyte replenisher, and it is an emetic.
The most important applications of sodium chloride in the chemical industry are in making a number of important industrial chemicals such as hydrochloric acid, sodium hydroxide, sodium carbonate, and metallic sodium. It is the starting material in manufacturing these substances. Other uses are in dyeing and printing fabrics, glazing pottery, in making soap, and for curing hides. Sodium chloride is a component of many freezing mixtures.

Химические свойства

Sodium chloride, NaCl, also known as common salt and halite, is a white crystalline solid.It is soluble in water,slightly soluble in alcohol, and melts at 804 °C (1480 °F). Sodium chloride is the most important sodium mineral and occurs naturally in seawater, underground deposits, and brine wells.Sodiumchlorideis a basic raw material for the production of chlorine,sodium hypochlorite, sodium bisulfate,soda ash, and hydrogen chloride. Sodium chloride is also used in food preparation, fertilizers, and by highway departments to control icy road conditions.

Физические свойства

Sodium chloride is the familiar compound commonly referred to as salt or table salt. Th e mineral form of sodium chloride is halite and is found in natural deposits throughout the world. It accounts for approximately 2.7% by weight of the dissolved minerals in seawater. Sodium chloride is an ionic compound existing as a white crystalline cubic structure of alternating sodium and chloride ions. Sodium chloride is essential for life, with the average adult requiring about 1 to 2 grams per day. Salt supplies sodium and provides numerous essential functions such as maintaining water balance in cells, taking part in nerve signal transmission and muscle contraction.

Вхождение

Sodium chloride is widely distributed in nature. Oceans are the vast source of sodium chloride. It occurs in seawater at an average concentration of 2.68 wt%. It also occurs in many inland saline waters and in salt deposits in sedimentary rocks, as the mineral halite.
Sodium chloride is probably the most important salt of both sodium and chlorine. Sodium chloride, common table salt, is an essential component of most food preparation, imparting flavor to food and providing the sodium nutritional requirement. Also, it is used for preserving food. Therapeutically, NaCl solution is used to combat dehydration as an electrolyte replenisher, and it is an emetic.
The most important applications of sodium chloride in the chemical industry are in making a number of important industrial chemicals such as hydrochloric acid, sodium hydroxide, sodium carbonate, and metallic sodium. It is the starting material in manufacturing these substances. Other uses are in dyeing and printing fabrics, glazing pottery, in making soap, and for curing hides. Sodium chloride is a component of many freezing mixtures.

Использование

sodium chloride (table salt) is used as a preservative, astringent, and anti-septic to treat inflamed lesions. It can also be used to mask odor, reduce product density, and control viscosity. Diluted solutions are not considered irritating.

Определение

ChEBI: An inorganic chloride salt having sodium(1+) as the counterion.

Методы производства

Sodium chloride occurs naturally as the mineral halite. Commercially, it is obtained by the solar evaporation of sea water, by mining, or by the evaporation of brine from underground salt deposits.

Подготовка

Sodium chloride is produced by solar evaporation of seawater or brine from underground salt deposits. It also is produced by mining rock salt. The commercial product contains small amounts of calcium and magnesium chlorides.

Общее описание

A white crystalline solid. Commercial grade usually contains some chlorides of calcium and magnesium which absorb moisture and cause caking.

Реакции воздуха и воды

Water soluble.

Профиль реактивности

Sodium chloride is generally unreactive. Releases gaseous hydrogen chloride if mixed with a concentrated nonvolatile acid such as sulfuric acid.

Пожароопасность

Literature sources indicate that Sodium chloride is nonflammable.

Сельскохозяйственное использование

Halite is a naturally occurring sodium chloride (NaCl) deposit. The most abundant potash mineral deposit is sylvite (KCl). Sylvite with halite forms the common potash ore, called sylvinite.

Фармацевтические приложения

Sodium chloride is widely used in a variety of parenteral and nonparenteral pharmaceutical formulations, where the primary use is to produce isotonic solutions.
Sodium chloride has been used as a lubricant and diluent in capsules and direct-compression tablet formulations in the past, although this practice is no longer common. Sodium chloride has also been used as a channeling agent and as an osmotic agent in the cores of controlled-release tablets. It has been used as a porosity modifier in tablet coatings, and to control drug release from microcapsules.
The addition of sodium chloride to aqueous spray-coating solutions containing hydroxypropyl cellulose or hypromellose suppresses the agglomeration of crystalline cellulose particles.(13) Sodium chloride can also be used to modify drug release from gels and from emulsions. It can be used to control micelle size, and to adjust the viscosity of polymer dispersions by altering the ionic character of a formulation.

Профиль безопасности

Poison by intraperitoneal and intracervical routes. Moderately toxic by ingestion, intravenous, and subcutaneous routes. An experimental teratogen. Human systemic effects by ingestion: blood pressure increase. Human reproductive effects by intraplacental route: terminates pregnancy. Experimental reproductive effects. Human mutation data reported. A skin and eye irritant. When bulk sodium chloride is heated to high temperature, a vapor is emitted that is irritating, particularly to the eyes. Ingestion of large amounts of sodium chloride can cause irritation of the stomach. Improper use of salt tablets may produce this effect. Potentially explosive reaction with dichloromaleic anhydride + urea. Electrolysis of mixtures with nitrogen compounds may form the explosive nitrogen trichloride. Reaction with burning lithmm forms the dangerously reactive sodmm. The molten salt at 11 00' reacts explosively with water. Violent reaction with BrF3. When heated to decomposition it emits toxic fumes of Cland Na2O.

Безопасность

Sodium chloride is the most important salt in the body for maintaining the osmotic tension of blood and tissues. About 5–12 g of sodium chloride is consumed daily, in the normal adult diet, and a corresponding amount is excreted in the urine. As an excipient, sodium chloride may be regarded as an essentially nontoxic and nonirritant material. However, toxic effects following the oral ingestion of 0.5–1.0 g/kg body-weight in adults may occur. The oral ingestion of larger quantities of sodium chloride, e.g. 1000 g in 600mL of water, is harmful and can induce irritation of the gastrointestinal tract, vomiting, hypernatremia, respiratory distress, convulsions, or death.
In rats, the minimum lethal intravenous dose is 2.5 g/kg bodyweight.
LD50 (mouse, IP): 6.61 g/kg
LD50 (mouse, IV): 0.65 g/kg
LD50 (mouse, oral): 4.0 g/kg
LD50 (mouse, SC): 3.0 g/kg
LD50 (rat, oral): 3.0 g/kg

Описание

Хлорид натрия или хлористый натрий (NaCl) — натриевая соль соляной кислоты. Известен в быту под названием поваренной соли, основным компонентом которой и является. Хлорид натрия в значительном количестве содержится в морской воде. Встречается в природе в виде минерала галита (каменной соли). Чистый хлорид натрия представляет собой бесцветные кристаллы, но с различными примесями его цвет может принимать голубой, фиолетовый, розовый, жёлтый или серый оттенок.

Химические свойства

Температура плавления +800,8 °С, кипения +1465 °С.

Умеренно растворяется в воде, растворимость мало зависит от температуры: коэффициент растворимости NaCl (в граммах на 100 г воды) равен 35,9 при +21 °C и 38,1 при +80 °C. Растворимость хлорида натрия существенно снижается в присутствии хлороводорода, гидроксида натрия, солей — хлоридов металлов. Растворяется в жидком аммиаке, вступает в реакции обмена. В чистом виде хлорид натрия не гигроскопичен. Однако соль часто бывает загрязнена примесями (преимущественно ионами Ca²⁺, Mg²⁺ и SO²⁻₄), и такая соль на воздухе сыреет. Кристаллогидрат NaCl · 2H2O можно выделить при температуре ниже +0,15 °C.

Смесь измельчённого льда с мелким порошком хлорида натрия является эффективным охладителем. Так, смесь состава 30 г NaCl на 100 г льда охлаждается до температуры −20 °C. Это происходит потому, что водный раствор соли замерзает при температуре ниже 0 °C. Лёд, имеющий температуру около 0 °C, плавится в таком растворе, 

Применение

В пищевой промышленности и кулинарии используют хлорид натрия, чистота которого должна быть не менее 97 %. Его применяют как вкусовую добавку и для консервирования пищевых продуктов.

Хлорид натрия имеет слабые антисептические свойства — 10-15%-ное содержание соли предотвращает размножение гнилостных бактерий. Этот факт обусловливает её широкое применение как консерванта.

В медицине Изотонический раствор хлорида натрия в воде (0,9 %) применяется как дезинтоксикационное средство, для коррекции состояния систем организма в случае обезвоживания, как растворитель других лекарственных препаратов.

Зимой хлорид натрия, смешанный с другими солями, песком или глиной — так называемая техническая соль — применяется как антифриз против гололёда. Ею посыпают тротуары, хотя это отрицательно влияет на кожаную обувь и техническое состояние автотранспорта ввиду коррозийных процессов.

хранилище

Aqueous sodium chloride solutions are stable but may cause the separation of glass particles from certain types of glass containers. Aqueous solutions may be sterilized by autoclaving or filtration. The solid material is stable and should be stored in a well-closed container, in a cool, dry place.
It has been shown that the compaction characteristics and the mechanical properties of tablets are influenced by the relative humidity of the storage conditions under which sodium chloride was kept.

Производство

Современная добыча хлорида натрия механизирована и автоматизирована. Соль массово добывается выпариванием морской воды (тогда её называют морской солью) или рассола с других ресурсов, таких как соляные источники и соляные озера, а также разработкой соляных шахт и добычей каменной соли.

Для добычи хлорида натрия из морской воды необходимы условия жаркого климата с низкой влажностью воздуха, наличие значительных низменных территорий, лежащих ниже уровня моря, или затопляемых приливом, слабая водопроницаемость почвы испарительных бассейнов, малое количество осадков в течение сезона активного испарения, отсутствие влияния пресных речных вод и наличие развитой транспортной инфраструктуры.

Методы очистки

It is recrystallised from a saturated aqueous solution (2.7mL/g) by passing in HCl gas, or by adding EtOH or acetone. It can be freed from bromide and iodide impurities by adding chlorine water to an aqueous solution and boiling it for some time to expel free bromine and iodine. Traces of iron can be removed by prolonged boiling of solid NaCl in 6M HCl; the crystals are then washed with EtOH and dried at ca 100o. Sodium chloride has been purified by sublimation in a stream of pre-purified N2 and collected by electrostatic discharge [Ross & Winkler J Am Chem Soc 76 2637 1954]. For use as a primary analytical standard, analytical reagent grade NaCl should be finely ground, dried in an electric furnace at 500-600o in a platinum crucible, and allowed to cool in a desiccator. For most purposes, however, drying at 110-120o is satisfactory.

Несовместимости

Aqueous sodium chloride solutions are corrosive to iron. They also react to form precipitates with silver, lead, and mercury salts. Strong oxidizing agents liberate chlorine from acidified solutions of sodium chloride. The solubility of the antimicrobial preservative methylparaben is decreased in aqueous sodium chloride solutions and the viscosity of carbomer gels and solutions of hydroxyethyl cellulose or hydroxypropyl cellulose is reduced by the addition of sodium chloride.

Регуляторный статус

GRAS listed. Included in the FDA Inactive Ingredients Database (injections; inhalations; nasal, ophthalmic, oral, otic, rectal, and topical preparations). Included in nonparenteral and parenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.