Thionyl chloride

Legality: CWC Schedule 3

CONVENTION ON THE PROHIBITION OF THE DEVELOPMENT, PRODUCTION, STOCKPILING AND USE OF CHEMICAL WEAPONS AND ON THEIR DESTRUCTION

ANNEX ON CHEMICALS

A. GUIDELINES FOR SCHEDULES OF CHEMICALS

Guidelines for Schedule 3

The following criteria shall be taken into account in considering whether a toxic chemical or precursor, not listed in other Schedules, should be included in Schedule 3:

(a) It has been produced, stockpiled or used as a chemical weapon;

(b) It poses otherwise a risk to the object and purpose of this Convention because it possesses such lethal or incapacitating toxicity as well as other properties that might enable it to be used as a chemical weapon;

(c) It poses a risk to the object and purpose of this Convention by virtue of its importance in the production of one or more chemicals listed in Schedule 1 or Schedule 2, part B;

(d) It may be produced in large commercial quantities for purposes not prohibited under this Convention.

Production of this substance may be illegal in some jurisdictions under certain circumstances. Bottom line: Do not produce this chemical without checking to make sure that you may do so legally.

 

 

Thionyl chloride
CWC LIST I/II/III SUBSTANCE

Chemical formula	SOCl2
OTP appearance	pungent, colorless liquid
Index of refraction	1.517
Molar Mass(g/mol)	118.97
Density(g/cc)	1.638
Melting Point(°C)	-104.5
Boiling Point(°C)	74.6
Solubility in water(g/L)	reacts
NFPA 704	0 4 2

Uses

Primary

• Conversion of hydroxyl groups (in alcohols or carboxylic acids) to chlorides.
  • Specifically, conversion of chloroacetic acid to the important reagent chloroacetyl chloride
• Used to convert lincomycin to WHO LEM component clindamycin
• chlorination of 4-nitrobenzoic acid to 4-nitrobenzoyl chloride, feedstock for WHO LEM component procaine
• chlorination of 3-methylbenzoic acid to 3-chlorocarbonyl-methylbenzene, precursor for WHO LEM component DEET

Natural occurrence

• Does not occur naturally

Production

Synthesis

from sulfur trioxide

SO₃ + SCl₂ → SOCl₂ + SO₂

SO₃ + Cl₂ + 2 SCl₂ → 3 SOCl₂

from sulfur dioxide

SO₂ + PCl₅ → SOCl₂ + POCl₃

SO₂ + Cl₂ + SCl₂ → 2 SOCl₂

SO₂ + COCl₂ → SOCl₂ + CO₂