Substrate selectivity and orientation in aromatic substitution by molecular fluorine
Preliminary results on this study, performed at low temperatures, in the dark, at nearly infinite F/sub 2/ dilution, and at substrate conversions approaching zero are reported. The relative reactivity of the substrates tested (nitrobenzene << benzene), (toluene << anisole), and the substituent orientations observed (predominately meta in nitrobenzene and ortho-para in toluene and anisole), characterizes the aromatic halogenations by elemental fluorine as a typical highly unselective electrophilic substitution. Fluorine selectivity appears to undergo a regular, modest increase with decreasing temperature, and an appreciable decrease when the reaction occurs in a more polar solvent. A plausible mechanism involving the electrophilic attack of a polarized fluorine molecule on the aromatic ring is suggested, but a detailed mechanism must await the results of further investigation.
- Research Organization:
- Brookhaven National Lab., Upton, NY
- OSTI ID:
- 6650602
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 100:11; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ANISOLE
AROMATICS
BENZENE
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELEMENTS
ETHERS
FLUORINATION
FLUORINE
GAS CHROMATOGRAPHY
HALOGENATION
HALOGENS
HYDROCARBONS
KINETICS
LIQUID COLUMN CHROMATOGRAPHY
LOW TEMPERATURE
MEDIUM TEMPERATURE
NITRO COMPOUNDS
NITROBENZENE
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
QUANTITY RATIO
REACTION KINETICS
SEPARATION PROCESSES
SOLVENTS
STEREOCHEMISTRY
SUBSTRATES
TEMPERATURE DEPENDENCE
TOLUENE