The Toxicity and Potential Dangers of Aliphatic and Aromatic Hydrocarbons *

The aliphatic hydrocarbons play an increasing role as solvents in different industries and the appraisal of the hazards connected with their use offers considerable difficulties because most of these solvents represent mixtures, sometimes of heterogeneous nature, and because their composition is frequently only incompletely known. In order to evaluate the potential dangers of such mixtures it is essential to be familiar with the toxicological and chemical properties of the individual members of such homologous series as the paraffins, olefines, acetylene derivatives, and saturated and unsaturated cycloparaffins. Of these the paraffins, or saturated hydrocarbons of the general formula C.H2.-2, are chemically quite inactive, as is indicated by their inertness towards concentrated sulfuric acid and cold fuming nitric acid, the former allowing their separation from olefines, acetylene derivatives, and aromatic hydrocarbons. The lower homologues of this group, methane, ethane, propane, and butane, are gases under ordinary conditions; those with from 5 to 15 carbons are liquids; the higher members are solids. Their boiling point increases with the molecular weight. The solubility in water of the gaseous members of this series increases from methane to butane and decreases with the higher homologues from pentane to octane. Data on the solubility of the paraffins in oil are rather incomplete and do