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furan chemical properties |
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mp |
-85.6 °c |
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bp |
67 °c10 mm hg(lit.) |
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density |
1.098 g/ml at 25 °c(lit.) |
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vapor density |
2.35 (vs air) |
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vapor pressure |
1672 mm hg ( 55 °c) |
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refractive index |
n20/d 1.5070(lit.) |
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fp |
160 °f |
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storage temp. |
2-8°c |
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water solubility |
insoluble |
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merck |
14,4296 |
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brn |
103221 |
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stability: |
stable. substances to be avoided include strong oxidising agents, acids, peroxides and oxygen. highly flammable; can form explosive mixtures with air. |
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cas database reference |
110-00-9(cas database reference) |
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nist chemistry reference |
furan(110-00-9) |
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epa substance registry system |
furan(110-00-9) |
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furan usage and synthesis |
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chemical properties |
furan is the simplest five membered oxygen-containing heterocyclic compounds with its molecular structure containing ring diene ether. it belongs to 6π electron-based compound with all the 5 atoms being sp2-hybrid and located in the same plane. the pair of non-shared electrons of the oxygen atoms occupied p-orbital which is perpendicular to the ring plane and is parallel and overlapping with the p-orbital of the four carbons atoms, forming a five-atoms& six-electrons conjugated closed system. therefore, it has a certain degree of aromatic nature. however, due to the electron density on the ring is not as uniform as benzene; it has a more active chemical property than benzene and can participate in many kinds of chemical reactions. it should be especially noted that, its 2, 5-position contains high electron density and prone to have nucleophilic substitution reaction. moreover, all the derivatives of almost happens in 2-position such as furfural, furfuryl alcohol and furan carboxylic acid. furan can also have nitrification, halogenated, sulfonated reaction. its diene bonds can also participate in addition reaction, for example, have reaction with maleic anhydride, having diene addition reaction and generating 7-bicyclo - [2.2.1] - hept-5-ene-2, 3-dicarboxylic anhydride.
under acidic condition, furan can have hydrolysis and ring open, producing 1, 4-dicarbonyl compounds. but once the furan ring has been introduced of electrophilic group, its activity can be greatly reduced and will not have diene reaction even encountering strong pro-diene compound. although it contains certain aromatic property, but this property is very weak and there are no free hydroxyl furan or amino furan like phenol and aniline. when furan is subject to hydrogenation, it can give rise to two kinds of hydrides, namely dihydrofuran (2, 3-dihydrofuran and 2, 5-dihydrofuran) and tetrahydrofuran with the former being partially saturated cyclic enol ether and the later being saturated. furan has a high thermal stability and is decomposed only at a temperature as high as 670 ℃ in the absence of catalyst. in the presence of a nickel catalyst, it is decomposed when heated to 360 ℃. this product is toxic and carcinogenic. the lethal concentration for rat through oral administration is 300mg / kg. its steam is narcotic which is similar as ether. it is easy to generate explosive peroxides in air.
its steam encounters pine wood chip pre-soaked with hydrochloride tablets and generate green color (pine wood chip reaction). this can be used to identify the presence of furan.
the above information is edited by the chemicalbook of dai xiongfeng. |
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raw material for organic synthesis |
furan is an important raw material in organic synthesis industry and can be used in the manufacture of many kinds of industrial chemical product such as pyrrole, thiophene tetrahydrofuran and benzofuran. it can also be applied to the manufacture of drugs such as anisodamine, atropine, toluoyl pyrrole sodium acetate, thiamine furan and furadantin and so on. furan, through oxidation and polymerization, can generate conductive poly-furan polymer with the conductivity being 18s/m (use asf5 as the oxidant) or 2.2 × 10-4s/m (with nosbf6 as the oxidant). furan is unstable and prone to be subject to oxidation and polymerization. furan, via catalytic hydrogenation, can generate tetrahydrofuran.
many furan derivatives are drugs such as furfural, furfuryl alcohol, furan carboxylic acid, nitrofurazone, furapromide and furosemide and so on. in some monosaccharides such as fructose and ribose as well as their derivatives, there exists the cyclic structure of hydrogenated furans. |
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application |
it is primarily used for the adhesive for the production of large quantities of hot-box technological cores.
furan can be used as the raw material of organic synthesis and solvents. furan can also be used for preparation of pyrrole, thiophene and tetrahydrofuran. tetrahydrofuran is an important derivative of furan with many important applications. furan, when undergoes etherfication and reduction to give 2, 5-dimethoxy dihydrofuran which is further converted to 2-hydroxy-1, 4-butanedial through hydrolysis, can be used for the production of anisodamine via synthetic approach; when furan undergoes etherfication and reduction to give 2, 5-dimethoxy tetrahydrofuran and generate butanedial via hydrolysis, is the raw material for synthesis of another kind of alkaloid, atropine. furan is also used to produce anti-inflammatory drugs toluoyl pyrrole sodium acetate with production of each ton of this product consuming 4.75 t of furan. |
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production method |
furfural is oxidized into 2-furan formic acid which undergoes decarboxylation to obtain furans. heat the 2-furan formic acid to 200-205 ℃ (around the boiling point) so it is decomposed into carbon dioxide and furans. during the reaction process, send the sublimated 2-furan formic acid back to the reactor with the distilled furan undergoing re-distillation; collect the distillation fraction of 31-34 ℃ which is the relative pure finished product with the overall yield being about 75%. industrially, it can be obtained through direct decarbonylation of furfural. the catalyst used in the reaction includes aluminum silicate, metal oxides or hydroxides as well as the mixtures of alloy or metals such as the mixture of zinc chromite and manganese. the reaction temperature should be about 400 ℃ with the yield being 90%. for large-scale production, the yield can be 74%. |
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category |
flammable liquid |
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toxicity grading |
poisoning |
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acute toxicity |
inhalation- rat lc50: 3398 ppm / per hour; inhalation-mouse lc50: 120 mg/m3/per hour. |
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explosive and hazardous characteristics |
mixing with air can be explosive. |
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flammability and hazard characteristics |
it is flammable in case of fire, high temperature and oxidant with burning releasing irritated fume. |
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storage characteristics |
treasury ventilation low-temperature and dry; store it separately from oxidants and acids. |
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extinguishing agent |
dry powder, dry sand, carbon dioxide, foam, 1211 fire extinguishing agent |
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professional standards |
tlv-twa 0.5 mg / m3 |
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chemical properties |
colourless liquid |
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usage |
furan is a five-membered heterocyclic aromatic ring. furan is used as a building block for the preparation of many heterocyclic compounds. |
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general description |
a clear colorless liquid with a strong odor. flash point below 32°f. less dense than water and insoluble in water. vapors heavier than air. |
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air & water reactions |
highly flammable. when uninhibited, furan forms explosive peroxides on exposure to air. insoluble in water. |
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reactivity profile |
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. . |
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health hazard |
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. |
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fire hazard |
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. |
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furan preparation products and raw materials |
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preparation products |
2,5-dimethoxytetrahydrofuran-->carbofuran-->pyrrole-->2-[3-(2-furyl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-->fenothiocarb-->fluvastatin sodium salt-->polypyrrole-polyvinyl chloride composite film-->cefuroxime-->dolasteron-->2-bromofuran-->2-acetylfuran-->2-nitrofuran-->efavirenz-->1,4-epoxy-1,4-dihydronaphthalene-->3-chloro-2-methylbiphenyl-->cladribine-->2-propionylfuran-->cefetamet hydrochloride-->gabexate mesylate-->bispyribac-sodium-->2-hexanoylfuran-->cabergoline-->exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride-->delavirdine |
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raw materials |
furfural-->2-furoic acid-->metallic oxides-->zinc chromate-->chromium(ii) chloride |
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