Petroleum benzine

Petroleum benzine is a hydrocarbon-based solvent mixture that is classified by its physical properties (e.g. boiling point, vapor pressure) rather than a specific chemical composition.

The chemical composition of a petroleum distillate can be modified to result in a solvent with a reduced concentration of unsaturated hydrocarbons, i.e. alkenes, by hydrotreating and/or reduced aromatics, e.g. benzene, toluene, xylene, by several dearomatization methods. The most important distinction amongst the various hydrocarbon solvents may be their boiling/distillation ranges (and, by association, volatility, flash point, etc.) and aromatic content.

Given the toxicity/carcinogenicity of some aromatic hydrocarbons, most notably benzene, the aromatic content of petroleum distillate solvents, which would typically be in the 10-25% (w/w) range for most petroleum fractions, can be advantageously reduced when their unique solvation properties are not required, and a less odorous, lower toxicity solvent is desired, especially when present in consumer products.

Petroleum benzine appears synonymous with petroleum spirit. Petroleum spirit is generally considered to be the fractions between the very lightest hydrocarbons, petroleum ether, and the heavier distillates, mineral spirits. For example, petroleum benzine with a boiling range of 36 - 83 °C sold by EMD Millipore under CAS-No. 64742-49-0 is identified in the product MSDS as hydrotreated light petroleum distillates comprising ≥ 90% C5-C7 hydrocarbons, n-alkanes, isoalkanes, and < 5% n-hexane, while Santa Cruz Biotechnology sells a petroleum ether product under the same CAS-No.

According to their corresponding MSDS, most commercially offered petroleum benzine solvents consist of paraffins (alkanes) with chain lengths of C5 to C9 (i.e. n-pentane to n-nonane and their isomers), cycloparaffins (cyclopentane, cyclohexane, ethylcyclopentane, etc.) and aromatic hydrocarbons (benzene, toluene, xylene, etc.).

The Toxic Substances Control Act Definition 2008 describes petroleum benzine as "a complex combination of hydrocarbons obtained by treating a petroleum fraction with hydrogen in the presence of a catalyst. It consists of hydrocarbons having carbon numbers predominantly in the range of C4 through C11 and boiling in the range of approximately -20°C to 190°C."