Tetramethylsuccinonitrile

Names Preferred IUPAC nameOther names Identifiers Abbreviations TMSN ChemSpiderECHA InfoCard100.129.378MeSHtetramethylsuccinonitrileUNIIProperties C₈H₁₂N₂Molar mass136.198 g·mol Appearance Colourless crystals Odorodorless Density1.07 g mL Melting point169.1 °C; 336.3 °F; 442.2 K Boiling pointsublimes Thermochemistry 13.6–16.2 kJ mol −4.8767–−4.8793 MJ mol Hazards GHS labelling: DangerH300, H310, H315, H319, H330, H370, H372, H412P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P302+P352, P304+P340, P305+P351+P338, P307+P311, P310, P314, P320, P321, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501Lethal dose or concentration (LD, LC): 38.9 mg/kg (rat, oral) 28 ppm (mouse, 3 hr)
6 ppm (rat, 30 hr) NIOSH (US health exposure limits): TWA 3 mg/m (0.5 ppm) [skin] TWA 3 mg/m (0.5 ppm) [skin] 5 ppm Safety data sheet (SDS) ICSC 1121Related compounds DBNPA

Tetramethylsuccinonitrile or TMSN is an organic compound with the formula (C(CH₃)₂CN)₂, classified as a dinitrile, and a colorless and odorlesssolid derived from 2,2'-azobis-isobutyronitrile, a common radical initiator in the manufacture of PVC:

[(CH₃)₂C(CN)]₂N₂ → [(CH₃)₂C(CN)]₂ + N₂.

Because PVC is pervasive and can contain TMSN, the safety aspects of this dinitrile has generated interest.

In regards to occupational exposures, the U.S. Occupational Safety and Health Administration and the U.S. National Institute for Occupational Safety and Health have set limits for dermal exposure at 3 mg/m over an eight-hour time-weighted average.