Аммиак химические свойства, назначение, производство
Описание
Ammonia is a colorless, pungent-smelling gas that is one of the most important industrial inorganic chemicals. It is widely used in fertilizers, refrigerants, explosives, cleaning agents, and as a feedstock to produce numerous other chemicals. Ammonia ranks as one of the top 10 chemicals produced annually.
Химические свойства
Ammonia is a colorless, strongly alkaline, and extremely soluble gas with a pungent, suffocating odor.
Strong ammonia solution occurs as a clear, colorless liquid having an exceedingly pungent, characteristic odor. It is lighter than air, and is formed as a result of the decomposition of most nitrogenous organic materials. The PhEur 6.0 states that concentrated ammonia solution contains not less than 25.0% and not more than 30.0% w/w of ammonia (NH3). The USP32– NF27 states that strong ammonia solution contains not less than 27.0% and not more than 31.0% w/w of ammonia (NH3).
Anhydrous ammonia, a major commercial chemical, is used in the manufacture of fertilizers, HN03, acrylonitrile, and other products, and as an electrolytic solvent.
Физические свойства
Colorless gas with a penetrating, pungent, suffocating odor. An experimentally determined odor
threshold concentration of 45.8 ppmv was reported by Leonardos et al. (1969). A detection odor
threshold concentration of 11.6 mg/m3 (16.7 ppmv) was experimentally determined by Nishida et
al. (1974).
История
During the Middle Ages ammonia was produced by the distillation of animal dung, hooves, and horn. Its preparation from horn gave it another name: spirit of hartshorn. Joseph Priestley (1733–1804) isolated ammonia in 1774 and called the compound alkaline air. The modern name ammonia was given to the compound in 1782 by the Swedish chemist Torbern Bergman (1735–1784). The exact chemical composition was determined by Claude-Louis Berthollet (1748–1822) in 1785. During the 19th century ammonia was obtained from the distillation of coal tar. The importance of nitrogen fertilizers in agriculture was established during the mid-1800s, and this coupled with the growth of the chemical industry provided incentive to find a method for fixing nitrogen.
Использование
Ammonia is a large-tonnage industrial product and finds its major use in the manufacture of nitric acid and fertilizers. It is the most commonly used refrigerant, particularly for large industrial installations.
Определение
ChEBI: An azane that consists of a single nitrogen atom covelently bonded to three hydrogen atoms.
Методы производства
Ammonia is obtained commercially chiefly by synthesis from its
constituent elements, nitrogen and hydrogen, which are combined
under high pressure and temperature in the presence of a catalyst.
Ammonia solution is produced by dissolving ammonia gas in water.
Общее описание
The product is a 0.4 M solution of ammonia in dioxane. Ammonia is a colorless gas with a characteristic strong odor. It is highly soluble in water, alcohol, chloroform and ether. It is extensively sold in the form of solution.1 Ammonia molecule is pyramidal in shape with nitrogen in the center and the three hydrogen atoms along the three vertices and the lone pair of electrons on the fourth vertex. Ammonia solution is commonly used as a base.
Реакции воздуха и воды
Soluble in water with evolution of heat. The amount of heat generated may be large.
Профиль реактивности
AMMONIA is a base. Reacts exothermically with all acids. Violent reactions are possible. Readily combines with silver oxide or mercury to form compounds that explode on contact with halogens. When in contact with chlorates Ammonia forms explosive ammonium chlorate [Kirk-Othmer, 3rd ed., Vol. 2, 1978, p. 470]. Reacts violently or produces explosive products with fluorine, chlorine, bromine and iodine and some of the interhalogen compounds (bromine pentafluoride, chlorine trifluoride). Mixing of bleaching powder (hypochlorite solution) with ammonia solutions produces toxic/explosive ammonia trichloride vapors. Undergoes potentially violent or explosive reactions on contact with 1,2-dichloroethane (with liquid ammonia), boron halides, ethylene oxide (polymerization), perchlorates or strong oxidants (chromyl chloride, chromium trioxide, chromic acid, nitric acid, hydrogen peroxide, chlorates, fluorine, nitrogen oxide, liquid oxygen). Reacts with silver chloride, silver oxide, silver nitrate or silver azide to form the explosive silver nitride. May react with some heavy metal compounds (mercury, gold(III) chloride) to produce materials that may explode when dry. [Bretherick, 5th ed., 1995, p. 1553].
Опасность
Inhalation of concentrated fumes may be
fatal. Moderate fire risk, explosive limits in air 16–
25%. Forms explosive compounds in contact with
silver or mercury. Eye damage and upper respiratory
tract irritant.
Угроза здоровью
Ammonia is intensely irritating to the eyes,nose, and respiratory tract. Toxic effectsinclude lachrymation, respiratory distress,chest pain, and pulmonary edema. A concentration of 10 ppm may be detected by odor;irritation of eyes and nose is perceptible atabout 200 ppm. A few minutes of exposureto 3000 ppm can be intolerable, causing seri ous blistering of the skin, lung edema, andasphyxia, leading to death. It is corrosive toskin because it reacts with moisture to formcaustic ammonium hydroxide. Long expo sure may result in destruction of tissues
LC50 value, inhalation (mice): 4200 ppm/hr.
Пожароопасность
Mixing of ammonia with several chemicals can cause severe fire hazards and/or explosions. Ammonia in container may explode in heat of fire. Incompatible with many materials including silver and gold salts, halogens, alkali metals, nitrogen trichloride, potassium chlorate, chromyl chloride, oxygen halides, acid vapors, azides, ethylene oxide, picric acid and many other chemicals. Mixing with other chemicals and water. Hazardous polymerization may not occur.
Воспламеняемость и взрывоопасность
Ammonia vapor is slightly flammable (NFPA rating = 1) and ignites only with
difficulty. Ammonia forms explosive mixtures with air in the range 16 to 25%.
Water, carbon dioxide, or dry chemical extinguishers should be used for ammonia
fires.
Фармацевтические приложения
Ammonia solution is typically not used undiluted in pharmaceutical
applications. Generally, it is used as a buffering agent or to adjust
the pH of solutions. Most commonly, ammonia solution (the
concentrated form) is used to produce more dilute ammonia
solutions.
Therapeutically, dilute ammonia solution is used as a reflex
stimulant in ‘smelling salts’, as a rubefacient, and as a counterirritant
to neutralize insect bites or stings.
Промышленное использование
Ammonia (NH3) is an alkaline gas with a sharp, penetrating odor. Reacting nitrogen and
hydrogen under pressure, in the presence of a catalyst, produces ammonia. Gaseous
ammonia is flammable in air at concentrations of 15–28% by volume. Anhydrous liquid
ammonia is a colorless liquid with a strong odor. Ammonia, because of its unique
chemical properties to metal ions, is primarily used in hydrometallurgical processing.
In the mineral processing industry, ammonia is rarely used as a pH regulator. There was
only one operating plant in the world that used ammonia as a pH regulator in treatment
of a copper/zinc ore.
Использование в материалах
Most common metals are not affected by dry
ammonia. However, when combined with water
vapor, ammonia will attack copper, zinc, or
alloys containing copper as a major alloying
element. Therefore, these materials should not
be used in contact with ammonia. Certain hightensile-
strength steel have developed stresscorrosion
cracking in ammonia service, but such
cracking can be prevented by the use of 0.2 percent
water by weight in the ammonia as an inhibitor.
Ammonia storage tanks and their valves
and fittings are usually made of steel.
Безопасность
Ingestion of strong solutions of ammonia is very harmful and causes
severe pain in the mouth, throat, and gastrointestinal tract as well as
severe local edema with cough, vomiting, and shock. Burns to the
esophagus and stomach may result in perforation. Inhalation of the
vapor causes sneezing, coughing, and, in high concentration,
pulmonary edema. Asphyxia has been reported. The vapor is
irritant to the eyes. Strong solutions are harmful when applied to the
conjunctiva and mucous membranes. Topical application of even
dilute ammonia solutions, used to treat insect bites, has caused
burns, particularly when used with a subsequent dressing.
When used as an excipient, ammonia solution is generally
present in a formulation in a highly diluted form.
Возможный контакт
Ammonia is used as a nitrogen source
for many nitrogen-containing compounds. It is used in the
production of ammonium sulfate and ammonium nitrate for
fertilizers; and in the manufacture of nitric acid, soda; synthetic
urea, synthetic fibers; dyes; and plastics. It is also
utilized as a refrigerant and in the petroleum refining and
chemical industries. It is used in the production of
many drugs and pesticides. Other sources of occupational
exposure include the silvering of mirrors, gluemaking, tanning
of leather; and around nitriding furnaces. Ammonia is
produced as a by-product in coal distillation and by the
action of steam on calcium cyanamide, and from the
decomposition of nitrogenous materials.
Экологическая судьба
Chemical/Physical. Reacts violently with acetaldehyde, ethylene oxide, ethylene dichloride
(Patnaik, 1992).
Reacts with acids forming water soluble ammonium salts.
хранилище
On exposure to the air, ammonia solution rapidly loses ammonia.
Ammonia solution should be stored in a well-closed container,
protected from the air, in a cool, dry place. The storage temperature
should not exceed 208℃.
Перевозки
Shipped in tank cars, tank trucks, barges, and
steel cylinders. Labeling and restrictions vary with concentration: NA1005 Ammonia, anhydrous, Hazard
Class: 2.2; Labels: 2.2-Nonflammable compressed gas,
Domestic (U.S.), Inhalation Hazard (Special Provision 13).
UN1005 Ammonia, anhydrous, Hazard Class: 2.3; Labels:
2.3-Poison Gas, 8-Corrosive material International,
Inhalation Hazard Zone D. UN2672 Ammonia solutions,
relative density between 0.880 and 0.957 @ 15 C in water,
with .10 % but NOT . 35 % ammonia, Hazard class: 8;
Labels: 8-Corrosive material. UN2073 Ammonia solution,
relative density less than 0.880 @ 15 C in water, with .
35% but NOT . 50% ammonia, Hazard Class: 2.2;
Labels: 2.2-Nonflammable compressed gas. Note: Also
used for Ammonium hydroxide, CAS1336-21-6, Record
A:0110.
Методы очистки
Dry the liquid, and store it, with sodium in a steel cylinder, then distil and condense it by means of liquid air, the non-condensable gases being pumped off. In order to obtain liquid NH3 from a cylinder, turn the cylinder upside-down (i.e. with the valve at the bottom, use a metal stand to secure it in this position) and lead a plastic tube from the tap to a measuring cylinder placed in an efficient fume cupboard which is kept running. Turn the tap on and allow the ammonia to be released. At first, gas and liquid will splatter out (make sure that the plastic tube is secure), but soon the liquid will drip into the measuring cylinder. The high latent heat of evaporation will cool the ammonia so that the liquid will remain cool and not boil vigorously. If the ammonia is required dry, the necessary precautions should be taken, i.e. the gas is allowed to flow through tubes packed with coarse CaO pellets. AMMONIA (gas, liquid or aqueous solution) is very irritating and should not be inhaled in any quantity as it can lead to olfactory paralysis (temporary or permanent).
Несовместимости
Ammonia solution reacts vigorously with sulfuric acid or other
strong mineral acids and the reaction generates considerable heat;
the mixture boils.
Утилизация отходов
Dilute with water, neutralize
with HCl and discharge to sewer. Recovery is an option to
disposal which should be considered for paper manufacture,
textile treating, fertilizer manufacture and chemical process
wastes.
Регуляторный статус
Included in the FDA Inactive Ingredients Database (oral suspensions,
topical preparations). Included in nonparenteral medicines
licensed in the UK. Included in the Canadian List of Acceptable
Non-medicinal Ingredients.
Аммиак препаратная продукция и сырье
сырьё
препарат