Chloromethyl methyl sulfide is the simplest unsymmetrical thioether bearing a reactive chloromethyl group. The compound is miscible with common organic solvents (dichloromethane, chloroform, ether, acetone, toluene) and only sparingly soluble in water (≈ 4 g L⁻¹ at 25 °C). The benzylic-like C–Cl bond is readily displaced by nucleophiles or eliminated with base, making the reagent valuable for one-carbon extensions under mildly basic conditions. Commercial material is stabilised with 0.1 % triethylamine and supplied at ≥98 % purity.
Key Physicochemical Data:
Boiling point: 106–108 °C (lit.)
Density: 1.15 g cm⁻³ (20 °C)
Refractive index: n²⁰/D 1.500
Flash point: 18 °C (closed cup)
Log P (octanol/water): 1.2 (predicted)
Typical Uses:
One-carbon electrophile for the introduction of the methylthio (MeS–) group into alcohols, phenols, carboxylic acids and heterocycles.
Precursor to methythiomethyl (MTM) ethers, versatile protecting groups that survive strong base and mild acid, removable with Hg(II) or Ag(I) salts.
Starting material for sulfonium ylides used in cyclopropanations and epoxidations, and for the preparation of odor-masked thio-formaldehyde equivalents.
Quality Specification (Commercial Grade):
Purity (GC): ≥98 %
Water content (KF): ≤0.1 %
Free acid (as HCl): ≤0.05 %
Stabiliser: triethylamine 0.1 %
Residue on ignition: ≤0.05 %
Hazard Statement:
Highly flammable liquid and vapour (H225). Causes skin and eye irritation (H315 + H319). Harmful if swallowed or inhaled. Keep away from heat, sparks, open flames and hot surfaces. Use explosion-proof equipment, gloves and eye protection. Store in a cool, tightly closed container under an inert atmosphere. SDS available on request.
