Alkyllead

Alkyllead refers to a class of organolead compounds used as anti-knock agents in gasoline to improve engine performance and efficiency. These compounds are typically tetraalkyllead compounds, with the general formula R4Pb, where R represents an alkyl group such as methyl, ethyl, or butyl. The most commonly used alkyllead compound is tetraethyllead (TEL), which was widely used in the mid-20th century.

The primary function of alkyllead compounds is to inhibit the autoignition of the fuel-air mixture in the engine cylinder, thereby reducing engine knocking and improving fuel efficiency. However, the use of alkyllead compounds has been largely phased out due to environmental and health concerns. Alkyllead compounds are highly toxic and can accumulate in the environment, leading to bioaccumulation in aquatic organisms and potential health risks for humans and wildlife.

The ban on alkyllead compounds began in the 1970s and was largely completed by the 1990s. The phase-out was driven by the discovery of the environmental and health impacts of lead, including its role in causing lead poisoning and its persistence in the environment. Today, alkyllead compounds are no longer used in gasoline, and alternative additives have been developed to achieve similar anti-knock performance without the associated environmental and health risks.