Fluorobenzene, also known as fluorobenzene, fluorinated benzene, and phenyl fluoride, is a product in which the hydrogen atoms on the benzene ring are replaced by fluorine atoms. It is a colorless liquid at room temperature and has a benzene smell. Molecular weight 96.10. Melting point -40℃. Boiling point: 84.73℃, 275℃ (3850kPa), 200℃ (1317kPa). Relative density 1.0225 (20/4℃). Refractive index 1.4677. Flash point -12℃. Miscible with ethanol, ether, acetone, benzene and carbon tetrachloride, but insoluble in water. It has higher thermal stability than benzene and does not decompose when heated at 350°C and 400 atmospheric pressure for 24 hours. Toxic and irritating, the limit allowable content in the air is 2.5 mg/m3. The condensation of fluorobenzene and γ-chlorobutyroyl chloride can produce γ-chloro-p-fluorobenzene, which is used to synthesize haloperidol. It is the most commonly used drug among the butyrophenone antipsychotics. Low toxicity, rat oral LD50>4000mg/kg, flammable. Can be derived from the reaction of aniline. Or derived from the action of diazobenzene hydrochloride and HF.
Uses: Identification reagents for plastics or resins, pesticide intermediates.
Fluorobenzene preparation method:
① Using aniline as raw material, react with sodium nitrite in concentrated hydrochloric acid to generate diazonium salt, then react the diazonium salt with fluoroboric acid at low temperature (-10°C), and finally pyrolyze to produce fluorobenzene. Concentrated HF can also be used instead of fluoroboric acid.
Or aniline can be reacted with sodium nitrite in anhydrous hydrofluoric acid at 0°C to generate fluorinated diazonium salt, and finally heated to 20°C to decompose, and fluorobenzene can also be produced.
② Using difluorochloromethane and cyclopentadiene as raw materials, first heat difluorochloromethane at 600°C, dehydrochloride, and add cyclopentadiene at the same time. Pentadiene can be dehydrofluorinated by continuing to heat to produce fluorobenzene. The yield of this method can reach 70%.
Extended reading:
Fluorobenzene and its derivatives developed rapidly after the 1960s. Its main varieties are:
1,2-Difluorobenzene[English 1,2-F2C6H4] is a colorless liquid at room temperature. There is a benzene smell. Relative molecular mass 114.09. Relative density 1.1599 (18℃). Melting point -34.0℃. Boiling point is 91~92℃ (100.1×103Pa). The refractive index is 1.4451. Flash point 2℃. Insoluble in water, soluble in acetone, benzene and chloroform.
1,4-difluorobenzene [English 1,4-F2C6H4]. Colorless liquid. Has a pungent odor. Slightly aromatic. Relative molecular mass 114.09. Relative density 1.1688. Melting point -13℃. Boiling point is 91~92℃ (100.1×103Pa). Refractive index 1.4967. Flash point 2℃.
1,3-difluorobenzene [English 1,3-F2C6H4]. Colorless liquid. Has a special pungent smell. Relative density 1.1630. Boiling point 82°C. Refractive index 1.4390. Flash point 2℃.
1,2,3-trifluorobenzene [English 1,2,3-F3C6H3]. Colorless liquid. Relative molecular mass 132.09. Relative density 1.280. Boiling point 94~95℃. Refractive index 1.4230. Flash point 3℃.
1,2,4-trifluorobenzene [English 1,2,4-F3C6H3]. Colorless liquid. Relative density 1.264. Boiling point is 88℃ (101.2×103Pa). Refractive index 1.4230. Flash point 4℃.
1,3,5-trifluorobenzene [English 1,3,5-F3C6H3]. Colorless liquid. Relative density 1.277. Melting point -5.5℃. Boiling point 75~76℃. Refractive index 1.4150. Flash point -7℃.
1,2,3,4-tetrafluorobenzene [English 1,2,3,4- F4C6H2]. Colorless liquid. Relative molecular mass 150.08. Relative density 1.400. Melting point -42℃. Boiling point is 93~94℃. Refractive index 1.4080. Flash point 20℃.
1,2,3,5-tetrafluorobenzene [English 1,2,3,5- F4C6H2]. Colorless liquid. Relative density 1.393. Boiling point 83℃. Refractive index 1.4040. Flash point 4℃.
1,2,4,5-Tetrafluorobenzene [English 1,2,4,5- F4C6H2]. Colorless liquid. Relative density 1.4255. Melting point is 4~5℃. Boiling point is 89~90℃. Refractive index 1.4075. Flash point 16℃.
Pentafluorobenzene[F5C6H]. Colorless liquid. Relative molecular mass 168.06. Relative density 1.514. Melting point -48℃. Boiling point 85℃. Refractive index 1.3900. Flash point 13℃.
Hexafluorobenzene[F6C6]. Colorless liquid. Has a benzene-like odor. Relative molecular mass 186.06. Relative density 1.6184. Melting point 5.3℃. Boiling point 80.5℃. Refractive index 1.3777. Flash point 10℃. Excellent flame retardancy and thermal stability. The reactivity characteristics of hexafluorobenzene are opposite to those of benzene, and it is prone to nucleophilic reactions. For example, it reacts with nucleophiles [Nu-] such as NH3, RNH2, and alcohol oxides to produce various pentafluorobenzene derivatives: Nu- = —NH2, — NHR, —OH, —OR,…
This product has low toxicity. Rat inhalation LD509500mg/m3 (2h). Used as raw material for high temperature resistant lubricants and flame retardants.
Fluorobenzene derivatives[FC6H4R]. Fluorobenzene is more prone to nucleophilic substitution reactions than chlorobenzene, mainly because the para position of the fluorine atom of the benzene ring is vulnerable to attack. For example, p-nitrofluorobenzene, p-chlorofluorobenzene, p-bromofluorobenzene, p-fluoroacetophenone, etc. are generated through nitration, halogenation or Freund-Kristen reaction. 4-Fluoro-4′-chlorobutyrophenone [1] made from fluorobenzene is a pharmaceutical sedative.
as fluorineThe preparation method of benzene derivatives and the halogen exchange method using chlorobenzene as raw material. For example, 3-chloro-4-fluoronitrobenzene [2] and 2,6-difluorocyanobenzene [3], which are intermediates for herbicides and pesticides, are both made using the halogen exchange method.
This method can also produce hexafluorobenzene from hexachlorobenzene, and the reaction temperature is 450 to 550°C.
The above information is edited and compiled by ChemicalBook Tongtong.
微信扫一扫打赏
