Ацетон циангидрин химические свойства, назначение, производство
Описание
Acetone cyanohydrin is an organic compound used in the production of methyl methacrylate,
the monomer of the transparent plastic polymethyl methacrylate (PMMA), also
known as acrylic. Acetone cyanohydrin is a flammable colourless liquid with a faint odour
of bitter almond. It is incompatible with sulphuric acid. Acetone cyanohydrin readily
undergoes decomposition by water to form hydrogen cyanide and acetone. Cassava tubers
contain linamarin, a glucoside of acetohydrin, and the enzyme linamarinase for hydrolysing
the glucoside. Crushing the tubers releases these compounds and produces acetone
cyanohydrin, which is potentially lethally toxic. Acetone cyanohydrin is classified as an
extremely hazardous substance in the U.S. Emergency Planning and Community Right-to-
Know Act. The principal hazards of acetone cyanohydrin arise from its ready decomposition
on contact with water, which releases highly toxic hydrogen cyanide.
Химические свойства
Acetone cyanohydrin is a flammable, colorless to light yellow liquid. Almond-like odor.
Использование
Acetone cyanohydrin is used to make methyl methacrylate; in the production of pharmaceuticals, foaming agents, and insecticides; and to produce polymerization initiators.
Методы производства
Acetone cyanohydrin is formed by adding acetone to sodium or potassium cyanide in water and treating with H2S04 or by reaction of acetone with hydrogen cyanide
(HSDB 1988; Windholz et al 1983). Technical acetone cyanohydrin may contain
as much as 0.2% free hydrogen cyanide. U.S. production in 1984 is estimated at
546,000 tons (HSDB 1988).
Общее описание
A colorless liquid. Flash point 165°F. Lethal by inhalation and highly toxic or lethal by skin absorption. Density 7.8 lb / gal (less dense than water). Vapors heavier than air. Produces toxic oxides of nitrogen during combustion.
Профиль реактивности
ACETONE CYANOHYDRIN readily decomposes to acetone and poisonous hydrogen cyanide gas on contact with water, acids (sulfuric acid) or when exposed to heat. Should be kept cool and slightly acidic (pH 4-5) [Sax, 2nd ed., 1965, p. 388]. Slowly dissociates to acetone, a flammable liquid, and hydrogen cyanide, a flammable poisonous gas, under normal storage and transportation conditions. Rate of dissociation increased by contact with alkalis and/or heat.
Угроза здоровью
Acetone cyanohydrin is considered very hazardous and should only be handled under conditions that prevent any inhalation of vapor or skin contact. May be slightly irritating to skin and mucous membranes.
Пожароопасность
Too dangerous to health to expose fire fighters; a few whiffs of vapor could cause death; vapor or liquid could be fatal on penetrating normal protective clothing. Vapor forms explosive mixture with air. Decomposes when heated to 248F or at lower temperature under alkaline conditions, emitting highly toxic hydrogen cyanide. May react violently with water. Contact with sulfuric acid may cause Acetone cyanohydrin to explode.
Промышленное использование
Actone cyanohydrin is used primarily in the preparation of methyl methacrylate,
which is polymerized to form various plastics, including plexiglas, and as intermediate
for resins (Hawley 1981). It also is employed for the manufacture of
insecticides; to produce oc-hydroxy-isobutyrate, a pharmaceutical intermediate; as
a complexing agent for metals; and as a reagent for chemical synthesis.
Профиль безопасности
Poison by ingestion,
skin contact, inhalation, intraperitoneal, and
subcutaneous routes. Readily decomposes to
HCN and acetone. Keep cool and do not
store for long periods. Combustible when
exposed to heat or flame. To fight fire, use
CO2, dry chemical, alcohol foam. Vigorous
reaction with H2SO4. When heated to
decomposition it emits toxic fumes of CN-.
Возможный контакт
Used in the manufacture of insecticides and making other chemicals, such as methyl methacrylate.
Метаболизм
Acetone cyanohydrin is readily absorbed by all routes (Hartung 1981). Shkodich
(1966) found no evidence of cumulative effects of acetone cyanohydrin in white
mice or albino rats over a period of 20 d in which daily doses of one-fifth of the
LD50s were given. Rapid detoxication and excretion were presumed to occur.
Acetone cyanohydrin may be largely metabolized to yield free cyanide (H?rtung
1981).
Перевозки
UN1541 Acetone cyanohydrin, stabilized, Hazard Class: 6.1; Labels: 6.1-Poison Inhalation Hazard, Inhalation Hazard Zone B.
Методы очистки
Dry the cyanohydrin with Na2SO4, and distil it as rapidly as possible under vacuum to avoid decomposition. Discard fractions boiling below 78-82o/15mm. Store it in the dark. USE AN EFFICIENT FUME HOOD as HCN (POISONOUS) is always present. [Cox & Stormont Org Synth Coll.Vol. II 7 1940, Beilstein 3 H 316, 3 IV 785.]
Несовместимости
May form explosive mixture with air. Not compatible with strong reducers, strong bases; strong oxidizers, and strong acids, such as hydrochloric, sulfuric (explosive), and nitric. Contact with strong acid and strong bases may cause explosions. Slowly decomposes to acetone and hydrogen cyanide gas at room temperatures; rate is accelerated by an increase in pH, contact with water, or temperature.
Утилизация отходов
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Add with stirring to strong alkaline calcium hypochlorite solution. Alternatively dissolve in flammable solvent and burn in incinerator with afterburner and scrubber.
Ацетон циангидрин препаратная продукция и сырье
сырьё
препарат