Tetramethyllead, also called tetra methyllead and lead tetramethyl, is a chemical compound used as an Antiknock agent additive for gasoline.[ Its use in gasoline is being phased out for environmental considerations.]
The National Institute for Occupational Safety and Health (NIOSH) in the United States has identified tetramethyllead as a potential workplace hazard. The recommended time-weighted average exposure limit to tetramethyllead is 0.075 milligrams per cubic meter during a 10-hour workday; the OSHA permissible exposure limit is the same value assuming an 8-hour workday.
Exposure to tetramethyllead can affect the central nervous system, the , and the cardiovascular system. Tetramethyllead can be absorbed through inhalation, through Human eye contact, through skin absorption, and by Ingestion the substance. Symptoms of exposure include insomnia, coma, seizure, mania, delirium, loss of appetite, nausea, hypotension, anxiety, Boredom, and . First aid measures for exposure include artificial respiration, immediate eye irrigation, and immediate washing with water. Immediate medical attention should be sought if tetramethyllead is ingested.
High heat can cause tetramethyllead to explosively decompose. Consequently it cannot be stored pure in sealed containers.
Tetramethyllead may be synthesized from disproportionate transmetalation of the quasi-Grignard reagent methylmagnesium chloride onto plumbous chloride:
- PbCl2 + MeMgCl → PbMe4 + Pb + MgCl2
The process requires substantial care, as both methyl chloride and tetramethyllead are extremely volatile.[
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