Hexafluorobenzene

Structural formula
General
Surname	Hexafluorobenzene
other names	Perfluorobenzene Hexafluorobenzene
Molecular formula	C 6 F 6
Brief description	colorless liquid
External identifiers / databases
CAS number 392-56-3 EC number 206-876-2 ECHA InfoCard 100.006.252 PubChem 9805 Wikidata Q412413
properties
Molar mass	186.05 g mol −1
Physical state	liquid
density	1.612 g cm −3 (25 ° C)
Melting point	3.7-4.1 ° C
boiling point	80-82 ° C
Vapor pressure	77 hPa (20 ° C)
solubility	almost insoluble in water
Refractive index	1.377 (20 ° C)
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 225 P: 210
Thermodynamic properties
ΔH f 0	−937.9 ± 8.34 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Hexafluorobenzene (C ₆ F ₆ ) is an aromatic compound. The molecule has the same structure as benzene , except that all hydrogen atoms have been replaced by fluorine atoms. It is a colorless, flammable liquid and non-polar, therefore not miscible with water. With its melting point of 3.7–4.1 ° C and its boiling point of 80–82 ° C, hexafluorobenzene hardly differs from its substitution inverse, pure benzene. It will u. a. used in ¹⁹ F-NMR spectroscopy .

presentation

A direct synthesis of hexafluorobenzene from benzene and fluorine is not possible. The synthesis route runs, for example, via the reaction of anhydrous potassium fluoride with hexachlorobenzene in an autoclave at 450–500 ° C:

${\displaystyle \mathrm {C_{6}Cl_{6}\ +\ 6\ KF\longrightarrow \ C_{6}F_{6}\ +\ 6\ KCl} }$

The first synthesis of the compound was developed between 1934 and 1936 by pyrolysis of tribromofluoromethane over platinum at about 630 ° C by Yvonne Désirant .

Individual evidence

1. ↑ ^{a b c d e f g} data sheet Hexafluorobenzene from Sigma-Aldrich , accessed on October 03, 2016 ( PDF ).
2. ↑ ^{a b} Data sheet Hexafluorobenzene, 99% (PDF) from Fisher Scientific , accessed October 1, 2014.
3. ↑ M. Krech, SJW Price, WF Yared: Determination of the Heat of Formation of Hexafluorobenzene . In: Canadian Journal of Chemistry . 50 (18), 1972, pp. 9235-9238, doi : 10.1139 / v72-471 .
4. ↑ RP Mason, W. Rodbumrung, PP Antich: Hexafluorobenzene: a Sensitive ¹⁹ F NMR Indicator of Tumor Oxygenation , in: NMR in Biomedicine , 1996 , 9  (3), pp 125-134 ( doi : 10.1002 / (SICI) 1099 -1492 (199605) 9: 3 <125 :: AID-NBM405> 3.0.CO; 2-F ).
5. ↑ NN Vorozhtsov, VE Platonov and GG Yakobson: Preparation of hexafluorobenzene from hexachlorobenzene , in: Russian Chemical Bulletin , 1963 , 12  (8), S. 1389 ( doi : 10.1007 / BF00847820 ).
6. ^ RE Banks: Fluorine Chemistry at the Millennium Fascinated by Fluorine . Elsevier, 2000, ISBN 978-0-08-053179-3 , pp. 491 ( limited preview in Google Book search).

literature

• Walter J. Pummer, Leo A. Wall: Reactions of Hexafluorobenzene , in: Science , 1958 , Vol. 127, No. 3299, pp. 643-644 ( doi : 10.1126 / science.127.3299.643 ).
• Harold Crosbie Fielding: Preparation of hexafluorobenzene and fluorochlorobenzenes , U.S. Patent 3,277,192, patented October 4, 1966.
• MD Bertolucci, RE Marsh: Lattice parameters of hexafluorobenzene and 1,3,5-trifluorobenzene at −17 ° C , in: J. Appl. Cryst. , 1974 , 7 , pp. 87-88 ( doi : 10.1107 / S0021889874008764 ).