To a flask containing 23.6 gm (0.25 mole) of dimethyl disulfide at - 1 5 ° to -20°C is slowly added dropwise 34 gm (0.25 mole) of freshly distilled sulfuryl chloride while keeping the temperature at -15° to -20°C. The reaction mixture is stirred for 1 hr, and then distilled to afford 37.1 gm (90%), b.p. 27-28°C (53-60 mm Hg); NMR, 2.91 ppm (singlet). The crude product can also be used without distillation since most of the material is product.