1,2-Difluoroethane is a saturated

hydrofluorocarbon Hydrofluorocarbons (HFCs) are man-made organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air condi ...

containing an atom of fluorine attached to each of two carbons atoms. The formula can be written CH₂FCH₂F. It is an isomer of

1,1-difluoroethane 1,1-Difluoroethane, or DFE, is an organofluorine compound with the chemical formula CHF. This colorless gas is used as a refrigerant, where it is often listed as R-152a (refrigerant-152a) or HFC-152a (hydrofluorocarbon-152a). It is also used as ...

. It has a HFC name of HFC-152 with no letter suffix. When cooled to cryogenic temperatures it can have different conformers, gauche and trans. In the liquid form these are about equally abundant and easily interconvert. As a gas it is mostly the gauche form. In the HFC-152 designation, 2 means two fluorine atoms, 5 means 5-1 or four hydrogen atoms, and 1 means 1+1 or two carbon atoms.

Formation

Ethylene reacts explosively with fluorine yielding a mixture of 1,2-difluoroethane and vinyl fluoride. With solid fluorine it will react when triggered by

near-infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...

radiation.

Properties

Critical temperature is 107.5 °C. If a C-H bond is over excited with too much vibration, the intramolecular vibrational relaxation takes 490

picoseconds A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10−12 or (one trillionth) of a second. That is one trillionth, or one millionth of one millionth of a second, or 0.000 000 000&nbs ...

. The F-C-C-F dihedral angle is about 72°. Natural bond orbital deletion bond calculations show that 1,2-difluoroethane prefers the gauche conformation due to hyperconjugation effects. Since F is much more electronegative than the C atom, it will have greater electron density for the bonding orbital ( Carbon-fluorine bond). Thus, C will have larger σ* orbital, which is stabilized through C-H

hyperconjugation In organic chemistry, hyperconjugation (σ-conjugation or no-bond resonance) refers to the delocalization of electrons with the participation of bonds of primarily σ-character. Usually, hyperconjugation involves the interaction of the electron ...

. This cis C-H bonds and the C-F σ* interactions are significant. The dihedral angle of about 72° is a result of decreasing hyper conjugative stability and decreasing steric destabilization.

Reactions

CH₂FCH₂F reacts with chlorine when treated with light. Two products are formed CH₂FCCl₂F and CHClFCHClF. The proportions of each depends on the solvent.

Uses

1,2-Difluoroethane is primarily used in Refrigerants, 39%; foam blowing agents, 17%; solvents, 14%; fluoropolymers, 14%; sterilant gas, 2%; aerosol propellants, 2%; food freezant, 1%; other, 8%; exports, 3%.

Safety

1,2-Difluoroethane is toxic when inhaled or when it comes into direct contact with the skin. Fluorocarbons are 4 to 5 times heavier than air, so it tends to concentrate in low-lying areas. This increases the risk of inhalation. 1,2-difluoroethane is toxic to humans through several mechanisms. First, because it has a high density, it can displace oxygen in the lungs causing suffocation. In addition, inhaled fluorocarbons causes the myocardium to become more sensitive to catecholamines, which results in deadly cardiac arrhythmias. When inhaled by rats, 1,2-difluoroethane is converted to

fluoroacetate Fluoroacetate may refer to: * Fluoroacetic acid * Sodium fluoroacetate {{Short pages monitor