thiodiglycol

Thiodiglycol (bis(2-hydroxyethyl)sulfide; CAS number 111-48-8) is an organosulfur compound with the formula C4H10O2S. It is a colorless to pale yellow, viscous liquid that is miscible with water and many organic solvents. Its structure consists of a central thioether linkage flanked by two hydroxyethyl groups.

Thiodiglycol is produced industrially as an intermediate in the manufacture of dyes, pigments, rubber chemicals and certain pharmaceuticals. It is used as a solvent, coupling agent, and chemical building block in organic synthesis, including the preparation of esters, ethers, and polymers. The compound’s hydroxyl groups impart moderate polarity and reactivity toward common chemical transformations.

Thiodiglycol has been noted historically for its role as a precursor and degradation product of sulfur mustard (mustard gas); because of this association it is subject to regulatory controls and monitoring in many jurisdictions. Its presence can be relevant in environmental and forensic analyses involving chemical contamination or verification of industrial processes.

In terms of health and safety, thiodiglycol is of moderate toxicity: it can cause skin and eye irritation, and prolonged or repeated exposure may have systemic effects. Standard industrial hygiene practices—ventilation, protective gloves and eyewear, and spill containment—are recommended. It is biodegradable under aerobic conditions but should be managed to prevent releases to the environment.

Analytical methods such as chromatography and mass spectrometry are commonly employed for identification and quantification in environmental, occupational and forensic contexts.