Alkane molecules. Molecular models of hexane (C6H14, right) and cyclohexane (C6H12). Carbon atoms are black and hydrogen atoms are white. Hexane is a colourless liquid that is insoluble in water. It is mainly used as a solvent, particularly in the extraction of oil from oil- seeds. Cyclohexane is also a colourless liquid. It is used in industry as an intermediate in the production of Nylon, as a solvent for oils, fats and waxes, and as a paint remover.