ABSTRACT
The short hydrocarbons (alkanes (CnH2n+2) and alkenes (CnH2n) are not commonly used as solvents because they are not liquid at room temperature. The longer ones (e.g., octane) comprise a substantial fraction of liquid fuels. Halogenated solvents - usually containing chlorine - are less volatile and flammable, and find frequent use as degreasing agents. The various classes of oxygen-containing hydrocarbons - alcohols, ketones, glycols, and ethers - differ considerably in chemistry and toxicity. Among the alcohols, ethanol possesses relatively low toxicity and is of course a commonly ingested intoxicant. Due to its social acceptability, its recreational use and abuse far exceed those of any other solvent today. With the exception of methanol in primates (see section on the visual system below), the toxicity of the other straight-chain alcohols increases with the length of the carbon chain. Ketones (e.g., acetone and methyl isobutyl ketone) and glycols (e.g., ethylene and propylene glycols) comprise two other classes of oxygen-containing solvents.
