1,1-difluoroethene

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Structural formula
Structure of 1,1-difluoroethene
General
Surname 1,1-difluoroethene
other names
  • 1,1-difluoroethylene
  • Vinylidene fluoride
  • Freon 1132a
  • R-1132a
  • Vinylidene difluoride VDF
Molecular formula C 2 H 2 F 2
Brief description

extremely flammable, colorless gas with a slightly ethereal odor

External identifiers / databases
CAS number 75-38-7
EC number 200-867-7
ECHA InfoCard 100,000,789
PubChem 6369
Wikidata Q161287
properties
Molar mass 64.03 g mol −1
Physical state

gaseous

density
  • 2.89 kg m −3 at 0 ° C and 1013 mbar
  • 1.12 g cm −3 (liquid at boiling point)
Melting point

−144  ° C

boiling point

−84 ° C

Vapor pressure

3.612 M Pa (20 ° C)

solubility

moderate in water (254 mg l −1 at 25 ° C)

safety instructions
GHS labeling of hazardous substances
02 - Highly / extremely flammable 04 - gas bottle

danger

H and P phrases H: 220-280
P: 210-377-381-410 + 403
Thermodynamic properties
ΔH f 0

−335.0 kJ / mol

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

1,1-Difluoroethene is a chemical compound from the group of aliphatic unsaturated fluorocarbons .

Extraction and presentation

There are various manufacturing processes for 1,1-difluoroethene, for example dechlorination of 1,2-dichloro-1,1-difluoroethane or dehydrofluorination of 1,1,1-trifluoroethane . The global production volume in 1999 was around 33,000 tons.

properties

1,1-Difluoroethene is an extremely flammable, colorless gas with a slightly ethereal odor. It is easy to polymerize and is sold in compressed gas cylinders in liquefied form. At higher temperatures it is chemically unstable. The critical temperature is 30.1 ° C, the critical pressure is 44.33 bar, the critical density is 6.51 mol·l −1 and the triple point temperature is −144 ° C (melting temperature).

use

1,1-Difluoroethene is used to make polyvinylidene fluoride and copolymers with chlorotrifluoroethylene and hexafluoropropylene .

safety instructions

1,1-Difluoroethene forms an explosive mixture with air. The explosion range is between 4.7% by volume (125 g / m 3 ) as the lower explosion limit (LEL) and 25.1% by volume (664 g / m 3 ) as the upper explosion limit (UEL). The ignition temperature is 390 ° C. The substance therefore falls into temperature class T2. During thermal decomposition, hydrogen fluoride is formed.

See also

Individual evidence

  1. ↑ a b c d e f g h Entry on 1,1-difluoroethene in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
  2. ↑ a b OECD : Screening Information Dataset (SIDS) Initial Assessment Report (SIAR) for Ethene, 1,1-difluoro- , accessed on November 4, 2014.
  3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-21.
  4. ↑ a b c Mears, WH; Steel, RF; Orfeo, SR; Shair, RC; Kells, LF; Thompson, W .; McCann, H .: Thermodynamic Properties of Halogenated Ethanes and Ethylenes in Ind. Eng. Chem. 47 (1955) 1449-1954, doi : 10.1021 / ie50547a052 .
  5. ^ A b E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.