Thiodiglycol, or bissulfide, is a viscous, clear to pale-yellow liquid used as a solvent. Its chemical formula is C4H10O2S, or HOCH2CH2SCH2CH2OH. It is miscible with acetone, alcohols, and chloroform. It is soluble in benzene, ether, and tetrachloromethane. Thiodiglycol is manufactured by reaction of 2-chloroethanol with sodium sulfide. It is structurally similar to diethylene glycol. Thiodiglycol has both polar and nonpolar solvent properties. It is used as a solvent in a variety of applications ranging from dyeing textiles to inks in some ballpoint pens. In chemical synthesis, it is used as a building block for protection products, dispersants, fibers, plasticizers, rubber accelerators, pesticides, dyes, and various other organic chemicals. In the manufacture of polymers, it is used as a chain transfer agent. As an antioxidant, it is used as an additive in lubricants. A relatively recent use of thiodiglycol is as a mounting medium in microscopy. The ability to vary the refractive index of the medium by varying the concentration of TDE in an aqueous solution, plus its relative lack of toxicity makes it highly desirable for such use. The refractive index of the solution can be varied anywhere from near that of water to that of glass. Wikipedia [ - ]

Thiodiglycol, or bissulfide, is a viscous, clear to pale-yellow liquid used as a solvent. Its... [ + ]