Difluorobenzenes
| Difluorobenzenes | |||||||
| Surname | 1,2-difluorobenzene | 1,3-difluorobenzene | 1,4-difluorobenzene | ||||
| other names | o- difluorobenzene | m- difluorobenzene | p- difluorobenzene | ||||
| Structural formula |
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| CAS number | 367-11-3 | 372-18-9 | 540-36-3 | ||||
| PubChem | 9706 | 9741 | 10892 | ||||
| Molecular formula | C 6 H 4 F 2 | ||||||
| Molar mass | 114.10 g mol −1 | ||||||
| Physical state | liquid | ||||||
| Melting point | −34 ° C | −59 ° C | −13 ° C | ||||
| boiling point | 92 ° C | 82 ° C | 88-89 ° C | ||||
| density | 1.158 g cm −3 (25 ° C) | 1.163 g cm −3 (25 ° C) | 1.11 g cm −3 (25 ° C) | ||||
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GHS labeling |
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| H and P phrases | 225 | 225-332 | 225 | ||||
| no EUH phrases | no EUH phrases | no EUH phrases | |||||
| 210 | 210-370 + 378-403 + 235 | 210 | |||||
In chemistry, the difluorobenzenes form a group of substances consisting of a benzene ring with two fluorine atoms (–F) as substituents . Their different arrangements ( ortho , meta or para ) result in three constitutional isomers with the empirical formula C 6 H 4 F 2 .
properties
The boiling points of the three isomers are relatively close to one another, while their melting points differ more clearly. The 1,4-difluorobenzene, which has the highest symmetry, has the highest melting point.
use
1,2-Difluorobenzene is used as a solvent for the electrochemical analysis of transition metal complexes. It is quite chemically inert, non-coordinating, and has a dielectric constant large enough to dissolve numerous electrolytes and metal complex salts. It is used instead of the common solvents such as acetonitrile , DMSO and DMF because these have coordinating properties.
literature
- MT Kirchner, D. Bläser, R. Boese, TS Thakur, GR Desiraju: "1,3-Difluorobenzene", in: Acta Cryst. , 2009 , E65 , o2668-02669; doi : 10.1107 / S1600536809038987 .
- Heinrich Mäder: Complexes of water with fluorinated benzenes: Microwave spectroscopic studies on structure and dynamics. (PDF file; 348 kB)
Individual evidence
- ↑ a b c d data sheet 1,2-difluorobenzene from Sigma-Aldrich , accessed on March 13, 2017 ( PDF ).
- ↑ Entry on 1,3-difluorobenzene at ChemBlink , accessed on March 13, 2017.
- ↑ a b c d data sheet 1,4-difluorobenzene from Sigma-Aldrich , accessed on March 13, 2017 ( PDF ).
- ↑ a b c data sheet 1,3-difluorobenzene from Sigma-Aldrich , accessed on March 13, 2017 ( PDF ).
- ↑ TR O'Toole, JN Younathan, BP Sullivan, TJ Meyer: "1,2-Difluorobenzene: A Relatively inert and Noncoordinating Solvent for Electrochemical Studies on Transition-Metal Complexes", in: Inorg. Chem. , 1989 , 28 (20), pp. 3923-3926; doi : 10.1021 / ic00319a032 .