Thionyl chloride

Structural formula
General
Surname	Thionyl chloride
other names	Sulfurous acid chloride Chlorothionyl Thionyl dichloride
Molecular formula	SOCl 2
Brief description	colorless, highly refractive, smelling liquid
External identifiers / databases
CAS number 7719-09-7 EC number 231-748-8 ECHA InfoCard 100,028,863 PubChem 24386 ChemSpider 22797 Wikidata Q409171
properties
Molar mass	118.97 g · mol -1
Physical state	liquid
density	1.638 g cm −3 (20 ° C)
Melting point	−104.5 ° C
boiling point	76 ° C
Vapor pressure	124 h Pa (20 ° C) 188 hPa (30 ° C) 435 hPa (50 ° C)
solubility	partly violent decomposition with water and alcohols
Refractive index	1.518 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 302-331-314-335 EUH: 014-029 P: 280-301 + 330 + 331-304 + 340-305 + 351 + 338-308 + 310
MAK	Switzerland: 1 ml m −3 or 5 mg m −3
Toxicological data	500-1274 ppm · 1 h ( LC 50 ,  rat ,  inh. ) 540 ppm x 4 h ( LC 50 ,  rat ,  inh. )
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

Thionyl chloride is a highly refractive colorless liquid, the dichloride of sulphurous acid .

history

Thionyl chloride was first obtained in 1849 by reacting sulfur dioxide with phosphorus pentachloride . After its suitability as a chlorinating reagent was recognized, it was manufactured and used on an industrial scale from around 1900.

properties

Bond lengths and angles of thionyl chloride

Thionyl chloride is a colorless to yellowish liquid that smokes in the air and decomposes in water or when heated or when exposed to light. Their vapors have a suffocating effect even at great dilution. The compound reacts violently with water and bases, as well as with some alcohols . When heated above 80 ° C it breaks down into sulfur dioxide , chlorine and disulphur dichloride , according to the equation:

${\displaystyle \mathrm {4\ SOCl_{2}\ \longrightarrow \ 2\ SO_{2}+S_{2}Cl_{2}+3\ Cl_{2}} }$

When reacting with water, hydrogen chloride and sulfur dioxide are formed:

${\displaystyle \mathrm {SOCl_{2(l)}+H_{2}O_{(l)}\ \longrightarrow \ 2\ HCl_{(g)}+SO_{2(g)}} }$

Manufacturing

Thionyl chloride is produced in the laboratory by introducing sulfur trioxide into sulfur dichloride or by passing sulfur dioxide over phosphorus pentachloride :

${\displaystyle \mathrm {SCl_{2}+SO_{3}\ \longrightarrow SOCl_{2}+SO_{2}} }$

${\displaystyle \mathrm {PCl_{5}+SO_{2}\ \longrightarrow POCl_{3}+SOCl_{2}} }$

use

• In lithium thionyl chloride batteries as cathode material

• Thionyl chloride is used industrially to produce the following substances:
  • aromatic sulfonic acid chlorides
  • Carboxylic acid chlorides from carboxylic acids :
    ${\displaystyle \mathrm {R{-}COOH+SOCl_{2}\ \longrightarrow \ R{-}CO{-}Cl+SO_{2}+HCl} }$
  • Alkyl chlorides from aliphatic alcohols :
    ${\displaystyle \mathrm {R{-}OH+SOCl_{2}\ \longrightarrow \ R{-}Cl+SO_{2}+HCl} }$

Individual evidence

1. ↑ ^{a b} entry on thionyl chloride. In: Römpp Online . Georg Thieme Verlag, accessed on May 2, 2014.
2. ↑ ^{a b c d e f g h i j k l} Entry on thionyl chloride in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
3. ↑ Data sheet Thionyl chloride from Sigma-Aldrich , accessed on October 3, 2016 ( PDF ).
4. ↑ Entry on Thionyl dichloride in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 7719-09-7 or thionyl chloride ), accessed on November 2, 2015.
6. ↑ M. Persoz: In: Compt. Rend. 28, 1849, pp. 86-88.
7. ↑ P. Kremers: In: Justus Liebigs Ann. Chem. 70, 1848, pp. 297-300.
8. ↑ H.-D. Lauss, W. Steffens: Sulfur Halides. In: Ullmann's Encyclopedia of Technical Chemistry . Wiley-VCH Verlag, Weinheim 2012, doi : 10.1002 / 14356007.a25_623 .
9. ↑ Thionyl chloride (7719-09-7) , University of Münster, accessed on November 4, 2014.
10. ↑ G. Brauer (Ed.): Handbook of Preparative Inorganic Chemistry. 2nd Edition. vol. 1, Academic Press, 1963, pp. 382-383.