Хлороводород

Описание

Раствор соляной кислоты представляет собой прозрачную, едкую водянистую жидкость, с резким раздражающим запахом. Сама по себе бесцветная, но из-за содержания примесей железа, хлора и прочего может иметь слегка желтоватый цвет. Является сильной одноосновной кислотой состоящей из газообразного хлороводорода, растворенного в воде. Тонет и смешивается с водой. Соляная кислота получается при растворении в воде газообразного хлороводорода. Другой способ получения, при хлорировании углеводородов из побочных газов (абгазов).

Описание

A water solution of hydrogen chloride of varied concentrations. It is a clear, colorless or slightly yellowish, corrosive liquid having a pungent odor. It is miscible with water and with alcohol. Concentrations of hydrochloric acid are expressed in percent by weight, or may be expressed in Baume degrees (Be0) from which percentages of hydrochloric acid and specific gravities may readily be derived. The usually available concentrations are 18°, 20°, 22°, and 23° Be. Concentrations above 13° Be (19.6%) fume in moist air, lose hydrogen chloride, and create a corrosive atmosphere. Because of these characteristics, suitable precautions must be observed during sampling and analysis to prevent losses. Note: Hydrochloric acid is produced by various methods that might impart trace amounts of organic compounds as impurities. The manufacturer, vendor, or user is responsible for identifying the specific organic compounds that are present and for meeting the requirements for organic compounds. Methods are provided for their determination. In applying the procedures any necessary standards should be used to quantitate the organic compounds present in each specific product.

Химические свойства

Hydrochloric acid, or hydrogen chloride, is either a colorless liquid with a pungent odor, or a colorless to slightly yellow gas that can be shipped as a liquefi ed compressed gas. The acid is used in the production of fertilizers, dyes, dyestuffs, artifi cial silk, and paint pig- ments, and in refi ning edible oils and fats. Hydrochloric acid is also used in electroplating, leather tanning, ore refi ning, soap refi ning, petroleum extraction, and pickling of metals, and is used in the photographic, textile, and rubber industries. In addition, hydrochloric acid is used as an antiseptic in toilet bowls against animal pathogenic bacteria, and in food processing as a starch modifi er.

История

Hydrochloric acid is a strong, corrosive acid that results when the gas hydrogen chloride dissolves in water.Ancient alchemists prepared hydrochloric acid and Jabbar ibn Hayyan, known in Latin as Geber (721–815), is credited with its discovery around the year 800. The original method of preparation involved reacting salt with sulfuric acid, producing sodium hydrogen sulfate and hydrogen chloride gas. The hydrogen chloride gas is captured and dissolved in water to produce hydrochloric acid. Hydrochloric acid was formerly called muriatic acid. Terms such as muriatic and muriate were used in association with chloride substances before the discovery and nature of chlorine were fully understood. The Latin term muriaticus means pickled from muri, which is the Latin term for brine. Chlorides were naturally associated with seawater salt solutions, as chloride is the principal ion in seawater.

Использование

Hydrochloric Acid is an acid that is the aqueous solution of hydro- gen chloride of varying concentrations. it is miscible with water and with alcohol. it is used as an acidulant and neutralizing agent.

Определение

A colorless fuming liquid made by adding hydrogen chloride to water:
HCl(g) + H₂O1. → H₃O₊(aq) + Cl_-(aq)
Dissociation into ions is extensive and hydrochloric acid shows the typical properties of a strong acid. It reacts with carbonates to give carbon dioxide and yields hydrogen when reacted with all but the most unreactive metals. Hydrochloric acid is used in the manufacture of dyes, drugs, and photographic materials. It is also used to pickle metals, i.e. clean the surface prior to electroplating. Hydrochloric acid donates protons with ease and is the strongest of the hydrohalic acids. The concentrated acid is oxidized to chlorine by such agents as potassium manganate(VII) and manganese( IV) oxide.

Методы производства

Hydrochloric acid is an aqueous solution of hydrogen chloride gas produced by a number of methods including: the reaction of sodium chloride and sulfuric acid; the constituent elements; as a by-product from the electrolysis of sodium hydroxide; and as a by-product during the chlorination of hydrocarbons.

Использование

Соляная кислота применяется при декапировании, травлении в гальванике, при пайке для очистки металлов, в гидрометаллургии. В пищевой промышленности в качестве регулятора кислотности, 10% раствор - в строительстве. Ингибированная кислота в сочетании с ПАВ очищает и дезинфицирует металлы и керамику. Квалификации ХЧ и ОСЧ используется в лабораторных и научных исследованиях.

Реакции воздуха и воды

Fumes strongly in moist air. Soluble in water with evolution of heat.

Профиль реактивности

ANHYDROUS HYDROGEN CHLORIDE is an anhydrous (no water) strong acid. Reacts rapidly and exothermically with bases of all kinds (including amines and amides). Reacts exothermically with carbonates (including limestone and building materials containing limestone) and hydrogen carbonates to generate carbon dioxide. Reacts with sulfides, carbides, borides, and phosphides to generate toxic or flammable gases. Reacts with many metals (including aluminum, zinc, calcium, magnesium, iron, tin and all of the alkali metals) to generate flammable hydrogen gas. Reacts violently with acetic anhydride, 2-aminoethanol, ammonium hydroxide, calcium phosphide, chlorosulfonic acid, 1,1-difluoroethylene, ethylenediamine, ethyleneimine, oleum, perchloric acid, b-propiolactone, propylene oxide, silver perchlorate/carbon tetrachloride mixture, sodium hydroxide, uranium(IV) phosphide, vinyl acetate, calcium carbide, rubidium carbide, cesium acetylide, rubidium acetylide, magnesium boride, mercury(II) sulfate [Lewis]. Undergoes a very energetic reaction with calcium phosphide [Mellor 8:841(1946-1947)]. Corrosive to metals and tissues and irritating to the eyes and respiratory system. Corrodes galvanized or copper-alloy metals (brass, bronze); fittings of stainless steel or mild or cast steel must therefore be used. Reacts with calcium carbide with incandescence [Mellor 5:862(1946-1947]. Absorption on mercuric sulfate becomes violent at 125°C. [Mellor 2, Supp. 1:462(1956)].

Опасность

Toxic by inhalation, strong irritant to eyes and skin. Questionable carcinogen.

Угроза здоровью

Gas concentrations of 50 to 100 ppm are tolerable for 1 hour. Concentrations of 1,000 to 2,000 ppm are dangerous, even for brief exposures. More severe exposures will result in serious respiratory distress and prolonged exposures will result in death. Mists of hydrochloric acid are considered less harmful than anhydrous hydrochloric acid, because droplets have no dehydrating action. Individuals with respiratory problems and digestive diseases may be adversely affected by low level exposures to the gas or mist.

Пожароопасность

Fire may produce irritating or poisonous gases. Containers may explode in heat of fire. At high temperatures, Hydrochloric acid decomposes into hydrogen and chlorine. The following materials should be avoided: Mercuric sulfate -- violent reaction with gaseous hydrochloric acid at 250F. Sodium -- reacts vigorously with gaseous hydrochloric acid. Acetic anhydride, 2-aminoethanol, ammonium hydroxide, chlorosulfonic acid, ethylene diamine, ethyleneimine, oleum, propiolactone, sodium hydroxide, sulfuric acid, and vinyl acetate -- increase in temperature and pressure when mixed with hydrochloric acid. Calcium phosphide -- energetic reaction with hydrochloric acid. Silver perchlorate and carbon tetrachloride -- when mixed in combination with hydrochloric acid forms a compound that detonates at 105F. Formaldehyde -- when mixed with hydrochloric acid forms a human carcinogen. Material reacts violently with bases and is corrosive with the generation of heat. Reacts with base metals, forming combustible gas (hydrogen). Reacts violently with strong oxidants forming toxic gas (chlorine). Avoid heat; at high temperatures Hydrochloric acid will decompose into hydrogen and chlorine.

Воспламеняемость и взрывоопасность

Noncombustible, but contact with metals may produce highly flammable hydrogen gas.

Фармацевтические приложения

Hydrochloric acid is widely used as an acidifying agent, in a variety of pharmaceutical and food preparations. It may also be used to prepare dilute hydrochloric acid, which in addition to its use as an excipient has some therapeutic use, intravenously in the management of metabolic alkalosis, and orally for the treatment of achlorhydria.

Промышленное использование

Hydrochloric acid (HCl) is soluble in water andis a strong mineral acid made by the action ofsulfuric acid on common salt, or as a byproductof the chlorination of hydrocarbons such asbenzene.HCl is used to some extent in pickling of metal prior to porcelain enameling.

Использование в материалах

Piping, valves, and other equipment used in direct contact with anhydrous hydrogen chloride should be of stainless steel or of cast or mild steel. Carbon steel may be used in some components, but only if their temperature is controlled to remain below about 265°F (l29°C). In the presence of moisture, however, hydrogen chloride will corrode most metals. Teflon, Kel F and Hastelloy will resist corrosion.
Smaller sized valves, such as those used on cylinders, constructed of aluminum-siliconbronze with Monel stems have had satisfactory service experience due to frequent maintenance. The satisfactory extension of these materials to other applications should be confirmed by testing prior to use.

Безопасность

When used diluted, at low concentration, hydrochloric acid is not usually associated with any adverse effects. However, the concentrated solution is corrosive and can cause severe damage on contact with the eyes and skin, or if ingested.
LD50 (mouse, IP): 1.4 g/kg
LD50 (rabbit, oral): 0.9 g/kg

Угроза здоровью

Соляная кислота опасна для человека её токсичные пары при вдыхании могут вызвать раздражение и воспаление глаз, носа и дыхательных путей, а также отек легких. При контакте с кожей вызывает серьезные химические ожоги. Долгосрочное профессиональное воздействие соляной кислоты вызывает у людей гастрит, хронический бронхит и дерматит. Работать с ней обязательно необходимо в спецодежде и средствах индивидуальной защиты.

хранилище

Splash goggles and rubber gloves should be worn when handling this acid, and containers of HCl should be stored in a wellventilated location separated from incompatible metals. Water should never be added to HCl because splattering may result; always add acid to water. Containers of hydrochloric acid should be stored in secondary plastic trays to avoid corrosion of metal storage shelves due to drips or spills.
Cylinders of hydrogen chloride should be stored in cool, dry locations separated from alkali metals and other incompatible substances.

Методы очистки

Pass it through conc H2SO4, then over activated charcoal and silica gel. It fumes in moist air. Hydrogen chloride in gas cylinders contains ethylene, 1,1-dichloroethane and ethyl chloride. The latter two may be removed by fractionating the HCl through a trap cooled to -112o. Ethylene is difficult to remove. HCl fumes in moist air. HARMFUL VAPOURS. Its solubility in H2O is 82% at 0o. A constant boiling aqueous solution (azeotrope) has b 108.6o/760mm with an HCl concentration of ~20%, and is called Hydrochloric acid (muriatic acid) (see above). [Schmeisser in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 280-282 1963.]

Несовместимости

Hydrochloric acid and hydrogen chloride react violently with many metals, with the generation of highly flammable hydrogen gas, which may explode. Reaction with oxidizers such as permanganates, chlorates, chlorites, and hypochlorites may produce chlorine or bromine.

Утилизация отходов

In many localities, hydrochloric acid or the residue from a spill may be disposed of down the drain after appropriate dilution and neutralization. Otherwise, hydrochloric acid and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines. Excess hydrogen chloride in cylinders should be returned to the manufacturer. For more information on disposal procedures, see Chapter 7 of this volume.

Регуляторный статус

GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (dental solutions; epidural injections; IM, IV, and SC injections; inhalations; ophthalmic preparations; oral solutions; nasal, otic, rectal, and topical preparations). Included in parenteral and nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.