Tetramethyllead

Tetramethyllead, also called tetra methyllead and lead tetramethyl, is a chemical compound used as an <a href="/facts/Antiknock_agent/drJDnGLL">antiknock</a> additive for <a href="/facts/Gasoline/lcnxq5BS">gasoline</a>. It is a <a href="/facts/Methyl_radical/TYS25r9w">methyl radical</a> synthon. Its use in gasoline is being phased out for environmental considerations.
The <a href="/facts/National_Institute_for_Occupational_Safety_and_Health/5WjdDNMN">National Institute for Occupational Safety and Health</a> (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 <a href="/facts/Occupational_Safety_and_Health_Administration/dCGbW5Ax">OSHA</a> permissible exposure limit is the same value assuming an 8-hour workday.
Exposure to tetramethyllead can affect the <a href="/facts/Central_nervous_system/k8I6To97">central nervous system</a>, the <a href="/facts/Kidney/HBspPrv9">kidneys</a>, and the <a href="/facts/Circulatory_system/WXwudzzc">cardiovascular system</a>. Tetramethyllead can be absorbed through <a href="/facts/Inhalation_exposure/mesmCWzV">inhalation</a>, through <a href="/facts/Human_eye/a24ua4fy">eye</a> contact, through <a href="/facts/Skin/4havlLzG">skin</a> absorption, and by <a href="/facts/Ingestion/VIsgnlnA">ingesting</a> the substance. Symptoms of exposure include <a href="/facts/Insomnia/C1TnQTb2">insomnia</a>, <a href="/facts/Coma/N9oQ7g7R">coma</a>, <a href="/facts/Epileptic_seizure/zuIrQyze">seizure</a>, <a href="/facts/Mania/qYV8BBbt">mania</a>, <a href="/facts/Delirium/f1zdzAc5">delirium</a>, <a href="/facts/Anorexia_(symptom)/G7RsaXp9">loss of appetite</a>, <a href="/facts/Nausea/dyhkcbeD">nausea</a>, <a href="/facts/Hypotension/BhrdVVRS">hypotension</a>, <a href="/facts/Anxiety_(mood)/Geekl883">anxiety</a>, <a href="/facts/Boredom/pe1f6vGT">restlessness</a>, and <a href="/facts/Nightmare/EhJvEEc2">nightmares</a>. First aid measures for exposure include <a href="/facts/Artificial_ventilation/Es8LzXWT">artificial respiration</a>, 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 <a href="/facts/Transmetalation/Mm0hQzp3">transmetalation</a> of the quasi-<a href="/facts/Grignard_reagent/0vkLtPo1">Grignard reagent</a> methylmagnesium chloride onto <a href="/facts/Plumbous_chloride/JPg6wVc3">plumbous chloride</a>:

PbCl2 + MeMgCl → PbMe4 + Pb + MgCl2
The process requires substantial care, as both <a href="/facts/Methyl_chloride/DvmeEgDS">methyl chloride</a> and tetramethyllead are extremely volatile.

Tetramethyllead open-in-new

Tetramethyllead