1. As another method of the separation of tert-butanol from the absorption product of isobutylene with sulphuric acid, without neutralisation of the acid with alkali, the extraction of tert-butanol with solvents has been investigated. It is necessary to dilute the acid after absorption of isobutylene before extraction. Ethyl ether has been found to be the most suitable solvent for the extraction. 2. tert-Butanol can be extracted almost completely from the acid phase, different from the case of secondary olefines. 3. The absorption of isobutylene with dilute sulphuric acid, in order to extract tert-butsaaol without dilution, has been found very slow even when the acid phase is saturated with Ag2SO4.