Thionyl chloride
| Thionyl chloride | |
|---|---|
| Missing image Thionyl_Chloride.PNG Chemical Structure of Thionyl Chloride | |
| General | |
| Systematic name | Thionyl dichloride |
| Other names | sulfurous oxychloride, sulfurous dichloride, sulfinyl chloride, sulfinyl dichloride, dichlorosulfoxide |
| Molecular formula | SOCl2 |
| Molar mass | 118.97 g/mol |
| Appearance | clear to yellow odorous liquid |
| CAS number | 7719-09-7 |
| MSDS | Wikisource MSDS |
| Bulk properties | |
| Density | 1.638 g/cm3 |
| Solubility | reacts with water |
| Melting point | -104.5 °C |
| Boiling point | 76 °C |
| Hazards | toxic, corrosive, lachrymatory, and a skin and inhalation hazard |
| Structure | |
Thionyl chloride (or thionyl dichloride) is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a liquid at room temperature and pressure. It is odorous, toxic, corrosive, lachrymatory, and a skin and inhalation hazard. It decomposes when heated above 140°C.
| Contents |
Reactions
Thionyl chloride is used both on a laboratory and an industrial scale. It reacts with water to release hydrogen chloride (HCl) and sulfur dioxide (SO2), and it is not found in nature.
Thionyl chloride reacts with carboxylic acids to produce acyl chlorides,
R-CO-OH + O=SCl2 → R-CO-Cl + SO2 + HCl
and with alcohols to produce alkyl chlorides.
R-OH + O=SCl2 → R-Cl + SO2 + HCl
Uses
Thionyl chloride is used inside lithium-thionyl chloride batteries as the positive active material with lithium as the negative active material. It is also used as a reagant for the production of other chemical compounds or materials. A major application is in the preparation of acid chlorides from carboxylic acids, including the important organic reactant acetyl chloride made via the following reaction:
H3C-COO-H + O=SCl2 → H3C-COCl + SO2 + H-Cl
Synthesis of Thionyl Chloride
The major industrial process is from the reaction of sulfur trioxide and sulfur dichloride[1]:
Other methods include:
Industrial production of thionyl chloride is controlled under the Chemical Weapons Convention, where it is listed in schedule 3.
References
- N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, 1984.