C8C18

C8C18 is a designation used in the chemical and petroleum industries to describe a hydrocarbon fraction that contains carbon atoms in the range from eight to eighteen per molecule. Because it denotes a fraction rather than a single compound, the exact mix can vary by source and refining process. The fraction often comprises linear and branched alkanes, with smaller amounts of cycloalkanes and, depending on processing, trace aromatic components.

These fractions are produced during crude oil refining through distillation, catalytic cracking, hydrocracking, or gas processing, and may be further treated or blended to meet specifications. The C8-C18 range includes compounds with a broad range of volatilities, so the fraction can behave as a solvent, a diluent, or a lubricant base stock, with lower members being more volatile than higher members.

Applications typically include use as solvents in paints, coatings, inks, cleaners, and personal care formulations; as diluents for adhesives; as base stocks for lubricants; as components in fuel blends or processing solvents; and in polymer manufacturing and extraction processes.

Safety and environmental considerations include the fact that these are flammable liquids that may pose inhalation or dermal hazards, requiring proper handling, storage, and ventilation. Environmental concerns include potential toxicity to aquatic life and air emissions, with biodegradability varying by composition. Regulatory status varies by jurisdiction and application, and may involve limits on volatile organic compound content and benzene exposure in certain fractions.

See also: alkanes, cycloalkanes, hydrocarbon solvents.