Метиламин химические свойства, назначение, производство
Химические свойства
Methylamine is a colorless, fi sh-like smelling gas at room temperature. It is used in a variety of industries, such as the manufacture of dyestuffs, treatment of cellulose, acetate rayon, as a fuel additive, rocket propellant, and in leather tanning processes.
Физические свойства
Colorless, flammable gas with a strong ammonia-like odor. An experimentally determined
recognition odor threshold concentration of 21 ppbv was reported by Leonardos et al. (1969). Odor
threshold concentrations of 4.7 ppmv and 35 ppbv were experimentally determined by Nishida et
al. (1979) and Nagata and Takeuchi (1990), respectively.
Использование
Methylamine is used in dyeing and tanning;in photographic developer, as a fuel additive,and as a rocket propellant. It is also usedin organic synthesis and as a polymerizationinhibitor. It occurs in certain plants, such asMentha aquatica.
Методы производства
Several methods are currently used for synthesis of methylamine. Virtually all
produce a mixture of primary, secondary, and tertiary amines which can be
continuously separated by distillation and extraction. The most commonly used
synthesis involves heating ammonium chloride and methyl alcohol (ratio varies
from 2:1 to 6:1, depending on desired ratio of amines) to about 300°C in the
presence of a catalyst such as zinc chloride. Alternatively, methylamine can be
synthesized by heating ammonium chloride and formaldehyde in the presence of
H2 and a hydrogenation catalyst such as nickel or platinum. Methylamine is
generally marketed as a liquid or a 33% aqueous solution (HSDB 1988).
Определение
ChEBI: The simplest of the methylamines, consisting of ammonia bearing a single methyl substituent.
Общее описание
A colorless gas or a liquid. Pungent fishy odor resembling odor of ammonia. The liquid boils at 20.3°F hence vaporizes rapidly when unconfined. Vapors are heavier than air and may collect in low-lying areas. Easily ignited under most conditions. Under prolonged exposure to intense heat the containers may rupture violently and rocket. Used for making pharmaceuticals, insecticides, paint removers, surfactants, rubber chemicals.
Реакции воздуха и воды
Highly flammable. Very soluble in water; the solutions are strongly basic and therefore corrosive. Liquid fumes in air.
Профиль реактивности
METHYLAMINE neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated in combination with strong reducing agents, such as hydrides.
Опасность
(Gas and liquid) Dangerous fire risk. Explosive limits in air 5–21%. Strong irritant to tissue.
Eye, skin and upper respiratory tract irritant.
Угроза здоровью
Exposures to methylamine are known to cause adverse health effects among occupational workers. The workers demonstrate symptoms of toxicity that include, but are not limited to, irritation to the eyes, nose, and throat. Studies have indicated that the compound causes injury to the eyes through corneal opacities and edema hemorrhages in the conjunctiva, and injury to the liver. Studies of Guest and Varma indicated no signifi cant deleterious effects on the internal organs or skeletal deformities in experimental mice
Пожароопасность
FLAMMABLE. POISONOUS GASES MAY BE PRODUCED IN FIRE. Containers may explode in fire. Flashback along vapor trail may occur. Vapor may explode if ignited in an enclosed area. Toxic nitrogen oxides may be formed. Vapors are heavier than air and may travel considerable distance to a source of ignition and flash back.
Промышленное использование
Methylamine and its hydrochloride salt are widely used in organic synthesis for
introducing the methylamino group. In 1976, industrial consumption was 32,000
tons/year. One of its most important uses is in the preparation of amide-type
surfactants. It is also used in the preparation of drugs such as adrenaline and
synthetic caffeine. It serves as the base for more than twenty commercial products,
among those included are photographic developers, insecticides, and antihistamine
drugs (Beard and Noe 1981). It is also widely used in tanning and has been
used in the separation of aromatics from aliphatic hydrocarbons (Sittig 1981).
Профиль безопасности
Poison by
subcutaneous route. Moderately toxic by
inhalation. A severe skin irritant. Mutation
data reported. A strong base. Flammable gas
at ordinary temperature and pressure. Very
dangerous fire hazard when exposed to heat,
flame, or sparks. Explosive when exposed to
heat or flame. To fight fire, stop flow of gas.
Forms an explosive mixture with
nitromethane. When heated to decomposition it emits toxic fumes of NOx.
See also AMINES.
Возможный контакт
Methylamine is used in organic
synthesis; a starting material for N-oleyltaurine, a surfactant; and p-N-methylaminophenol sulfate, a photographic
developer. It has possible uses in solvent extraction systems
in separation of aromatics from aliphatic hydrocarbons.
It is also used in the synthesis of many different pharmaceuticals; pesticides and rubber chemicals.
Канцерогенность
Methylamine was positive in the
mouse lymphoma assay and negative in the Ames assay.
Экологическая судьба
Photolytic. The rate constant for the reaction of methylamine and OH radicals in the atmosphere
at 300 K is 1.3 x 10-13 cm3/molecule?sec (Hendry and Kenley, 1979).
Low et al. (1991) reported that the photooxidation of aqueous primary amine solutions by UV
light in the presence of titanium dioxide resulted in the formation of ammonium and nitrate ions.
Chemical/Physical. In an aqueous solution, chloramine reacted with methylamine to form Nchloromethylamine
(Isaac and Morris, 1983).
Reacts with acids forming water-soluble salts.
хранилище
Methylamine is stored in a cool, well-ventilated noncombustible area separatedfrom possible sources of ignition andoxidizing substances and mercury. Itssolutions are stored in a flammable liquidstorage room or cabinet. The gas is shippedin steel cylinders or tank cars; the liquid isshipped in steel drums or tank cars.
Перевозки
UN1061 Methylamine, anhydrous, Hazard Class:
2.1; Labels: 2.1-Flammable gas. UN1235 Methylamine,
aqueous solution, Hazard Class: 3; Labels: 3-Flammable
liquid, 8-Corrosive material. Cylinders must be transported
in a secure upright position, in a well-ventilated truck.
Protect cylinder and labels from physical damage. The
owner of the compressed gas cylinder is the only entity
allowed by federal law (49CFR) to transport and refill
them. It is a violation of transportation regulations to refill
compressed gas cylinders without the express written permission of the owner.
Методы очистки
Dry the amine with sodium or BaO. It is commercially available in metal cylinders. [Beilstein 4 IV 118.]
Несовместимости
A medium-strong base. Reacts violently
with strong acids; mercury, strong oxidizers; nitromethane.
Corrosive to copper, zinc alloys; aluminum, and galvanized
surfaces.
Утилизация отходов
Return refillable compressed
gas cylinders to supplier. Controlled incineration (incinerator
equipped with a scrubber or thermal unit to reduce nitrogen
oxides emissions).
Метиламин препаратная продукция и сырье
сырьё
препарат