Фуран химические свойства, назначение, производство
Описание
Furan occurs naturally in oils distilled from rosin containing
pinewood. In addition, many natural foods contain the furan
ring structure and substituted furans may be formed through
cooking of simple carbohydrates. Furan is also found in
tobacco smoke as well as wood smoke and gas emissions from
gasoline and diesel engines. Furan has also been detected in
industrial effluents and can be emitted to the air from petroleum
refineries and coal-mining and gasification plants.
Химические свойства
Furan is a cyclic dienic ether stabilized by benzene-like resonance. Because of its conjugated unsaturation and heterocyclic atom, furan will undergo many types of reactions. It is, therefore, of interest as a chemical intermediate for pharmaceuticals, insecticides and fine chemicals. The heterocyclic oxygen atom in a ring with conjugated unsaturation gives furan a combination of ether, aromatic and olefinic characteristics. This polyfunctionality permits it to undergo a variety of reactions. Compared to benzene, the furan ring has greater reactivity, and is more susceptible to cleavage, thus resembling the vinyl ethers. Like the vinyl ethers, the furan ring is cleaved by aqueous acids. This reaction is accompanied by resinification .
Использование
Furan is a five-membered heterocyclic aromatic ring. Furan is used as a building block for the preparation of many heterocyclic compounds.
Определение
A heterocyclic liquid organic
compound. Its five-membered ring contains
four carbon atoms and one oxygen
atom. The structure is characteristic of
some monosaccharide sugars (furanoses).
Общее описание
Furan is a stable, colourless chemical liquid. It is highly flammable and forms explosive mixtures with air. It is incompatible with many other chemical substances, for example, strong oxidising agents, acids, peroxides, and oxygen. Furan is produced commercially by decarbonylation of furfural. It is used mainly in the production of tetrahydrofuran, thiophene, and pyrrole. It also occurs naturally in certain woods and during the combustion of coal and is found in engine exhausts, wood smoke, and tobacco smoke.
Реакции воздуха и воды
Highly flammable. When uninhibited, Furan forms explosive peroxides on exposure to air. Insoluble in water.
Профиль реактивности
Furan is sensitive to heat and may turn brown upon standing. Furan may be light sensitive. When uninhibited, Furan forms explosive peroxides on exposure to air. Furan may react with oxidizers, acids, peroxides and oxygen. Furan resinifies on evaporation or when in contact with mineral acids, but Furan is stable in alkalis. .
Опасность
Flammable, dangerous fire risk, flammable
limits 2–24%, forms peroxides on exposure to air.
Absorbed by skin. Possible carcinogen.
Угроза здоровью
The vapors are narcotic. Acute exposure to Furan by inhalation may involve both reversible and irreversible changes. Acute exposure by ingestion or skin absorption, as well as chronic exposure, are associated with high toxicity.
Пожароопасность
Very dangerous, upon exposure to heat or flame. Furan may form unstable peroxides on exposure to air. Contact with acids can initiate a violent, heat producing reaction. Avoid acids, oxidizing agents. Upon standing in air, Furan may form unstable peroxides.
Профиль безопасности
Confirmed carcinogen.
Poison by inhalation and intraperitoneal
routes. Moderately toxic by ingestion and
skin contact. Experimental reproductive
effects. A narcotic. Mutation data reported.
The exposure concentration limit of 10 ppm
together with its low boiling point requires
that adequate ventilation be provided in
areas where ths chemical is handled.
Contact with liquid must be avoided since
this chemical can be absorbed through the
skin. Washing thoroughly with soap and
water followed by prolonged rinsing should
be done immedlatelp after accidental
contact.
A very dangerous fire hazard when
exposed to heat or flame; can react with
oxidzing materials. Unstabdized, it may
form unstable peroxides on exposure to air and should always be tested before
ddlation. Washing with an aqueous
solution of ferrous sulfate slightly acidified
with sodum bisulfate will remove these
peroxides. Confirm by test. Contact with
acids can initiate a violent exothermic
reaction. Moderate explosion hazard when
exposed to flame. Furan's low bohg point
makes it easy to obtain explosive
concentrations of the vapor in inadequately
ventilated areas. To fight fire, use CO2, dr).
chemical. When heated to decomposition it
emits acrid smoke and irritating fumes. See
also PEROXIDES.
Возможный контакт
Furan is used as a chemical intermedi ate in the production of herbicides and pharmaceuticals; for
making tetrahydrofuran; in formation of lacquers; as a sol vent for resins in organic synthesis, especially for pyrrole,
thiophene.
Канцерогенность
Furan is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
Экологическая судьба
Furan may be released to the environment as a waste industrial
product or from unintentional or accidental releases. If released
to soil, it is expected to volatilize. If released to water, furan is not
expected to adsorb to suspended particles and sediment and is
likely to volatilize to ambient air. Sulfate-reducing bacteria can
degrade furan. However, under nonsulfate-reducing conditions,
biodegradation in soil and water is expected to be slow. In the
air, furan will exist as a vapor and will be subject to degradation
by reacting with hydroxyl radicals.
Перевозки
UN2389 Furan, Hazard Class: 3; Labels:
3-Flammable liquid.
Методы очистки
Shake it with aqueous 5% KOH, dry it with CaSO4 or Na2SO4, then distil it under nitrogen, from KOH or sodium, immediately before use. A trace of hydroquinone could be added as an inhibitor of oxidation. [Beilstein 17 H 27, 17 I 16, 17 II 34, 17/1 V 291.]
Несовместимости
May form explosive mixture with air.
Incompatible with oxidizers (chlorates, nitrates, peroxides,
permanganates, perchlorates, chlorine, bromine, fluorine,
etc.); contact may cause fires or explosions. Keep away
from alkaline materials, strong acids, amines, strong bases,
reducing agents. Unless stabilized with an inhibitor, air
exposure forms unstable peroxides.
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 govern ing storage, transportation, treatment, and waste disposal.
Фуран препаратная продукция и сырье
сырьё
препарат
Флувастатин натриевая соль
Cefetamet hydrochloride
Каберголин
Bispyribac-sodium
2-НИТРОФУРАН
EXO-3,6-EPOXY-1,2,3,6-TETRAHYDROPHTHALIC ANHYDRIDE
2-ацетилфуран
Супрофен
2-[3-(2-FURYL)PHENYL]-4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLANE
Пиррол
Кладрибин
Gabexate mesylate
КАРБОФУРАН
1,4-EPOXY-1,4-DIHYDRONAPHTHALENE
FENOTHIOCARB
2,5-диметокситетрагидрофурана
3-CHLORO-2-METHYLBIPHENYL
Эфавиренз
Цефуроксим
polypyrrole-polyvinyl chloride composite film
Делавирдин
2-Hexanoylfuran
2-бромфуран
2-Propionylfuran