Coleman fuel is a mixture of cyclohexane, nonane, octane, heptane, and pentane. Solvents used for this preparation include benzene, cyclohexane, and diethyl ether. Chemists have long known of rings containing carbon, e.g. benzene, pyridine, and cyclohexane. Via hydrogenation, benzene and its derivatives convert to cyclohexane and derivatives. Some liquids contained residual solvents such as 1,3-butadiene, cyclohexane, and acetone. Rhodium catalysts are also used to reduce benzene to cyclohexane. It is the carboxylic acid of cyclohexane. For example, cyclohexane and dioxane may be written as codice 35 and codice 36 respectively. Producers of cyclohexane account for approximately 11.4% of global demand for benzene. Cyclohexyl is the alkyl substituent of cyclohexane and is abbreviated Cy. Of these benzene and cyclohexane have been used the most extensively. Cycloalkanes reported as LOHC include cyclohexane, methyl-cyclohexane and decalin. Although rather unreactive, cyclohexane undergoes catalytic oxidation to produce cyclohexanone and cyclohexanol. The conformations of the pyranose ring are superficially similar to that of the cyclohexane ring.