2-Methylpentane

2-Methylpentane (isohexane) is a branched C6 aliphatic hydrocarbon with a boiling point of approximately 60°C and vapor pressure of ~208 hPa at 20°C. The low boiling point and high vapor pressure make it one of the fastest-evaporating light hydrocarbon solvents commercially available, which is why it appears at 40–50% concentrations in MAF sensor cleaners — the sensing element must be residue-free before reinstallation and must reach that state in 2–3 minutes of air-drying at ambient temperature.

2-Methylpentane is a component of the hexane isomer family. Unlike n-hexane (CAS 110-54-3), which carries a specific H361 male reproductive toxin classification and known peripheral neuropathy risk from repeated occupational exposure, 2-methylpentane's hazard profile is primarily narcotic effects from acute inhalation at high concentrations. NIOSH sets a conservative ceiling TLV for hexane isomers as a class; 2-methylpentane specific occupational exposure limits are listed by ACGIH (STEL 1000 ppm) based on CNS depression rather than reproductive endpoints.

At the consumer use profile (2–4 short bursts during a MAF sensor cleaning), the primary concern is the flammability hazard (flash point well below −17°C) and ensuring adequate ventilation during the brief spray, not chronic neuropathy risk. The H225 flammable liquid classification drives the fire-safety precautions required during use.