In the "direct process," the acid protonates the alkene, and water reacts with this incipient carbocation to give the alcohol. The direct process is more popular because it is simpler. The acid catalysts include phosphoric acid and several solid acids.[1] Here an example reaction mechanism of the hydration of 1-methylcyclohexene to 1-methylcyclohexanol: Many alternative routes are available for producing alcohols, including the hydroboration–oxidation reaction, the oxymercuration–reduction reaction, fermentation and reduction of ketones and aldehydes.