2-Ethylhexyl mercaptan is a sterically hindered, high-boiling thiol (188 °C @ 760 mm Hg; flash-point 56 °C) The product is essentially insoluble in water (25 mg L⁻¹) but miscible with hydrocarbons, ethers and most common plasticisers. Its main outlet is as a sulphur building-block for the synthesis of PVC heat stabilisers: esterification with thio-succinic acid gives bis(2-ethylhexyl) mercapto-succinate, a widely used costabiliser that prevents early dehydrochlorination and colour formation by exchanging labile chlorine atoms for thio-ether linkages. The same thiol is also chain-extended with epichlorohydrin to produce poly(2-ethylhexyl-thio-ether-glycidyl) oligomers that function as internal plasticisers and odour-maskers in halogen-containing polymers. In the flavour & fragrance area the material is FEMA-GRAS (No. 4292) and is added to baked goods, meat seasonings and soft drinks at 0.1–5 mg kg⁻¹ to impart a savoury, meaty aroma; in perfume compositions it serves as a trace green-citrus top-note. Because of its low vapour pressure (0.8 mm Hg @ 25 °C) the compound is classified only as a flammable liquid (UN 3336, Packing Group III); nevertheless it is an eye and respiratory-tract irritant and a potential skin sensitiser (LLNA EC₃ 2.3 %). Store under nitrogen at 2–8 °C to minimise oxidation to the disulfide.
