Secondary alcohol molecule. Molecular model of secondary butanol (C4H10O), also known as butan-2-ol, secondary butyl alcohol or methylethyl carbinol. Carbon atoms are black, hydrogen atoms are white and oxygen atoms are red. Butan-2-ol is produced from the butane-butene fraction of gas that is produced during the cracking of petroleum. Butan-2-ol is used to manufacture butanone, an important industrial solvent.