Abstract: A process is described for the production of hydrocarbons with a high octane number starting from hydrocarbon cuts containing isobutene by selective dimerization with acid catalysts, characterized in that the dimerization reaction is carried out in the presence of tertiary alcohols, alkyl ethers and primary alcohols in such a quantity as to have, in the feeding, a molar ratio tertiary alcohols+alkyl ethers+primary alcohols/isobutene higher than 0.1, a molar ratio tertiary alcohols/isobutene lower than 0.2 and a molar ratio primary alcohols/isobutene lower than 0.2, preferably operating at a reaction temperature ranging from 30 to 120° C., at a pressure lower than 5 MPa and feeding space velocities of less than 30 h−1.

Abstract: Liquid mixture suitable as gasoline characterized in hat it has a RON octane number equal to or higher than 90 and a MON octane number equal to or higher than 80 and that it essentially consists of: a typical gasoline cut, having a boiling point ranging from 30 to 220° C. consisting of hydrocarbon compounds; one or more compounds deriving from the selective oligomerization of isobutene, which may optionally have been at least partially hydrogenated, in a quantity ranging from 0.5 to 20% by weight, wherein the dimers of isobutene and possible co-dimers of isobutene with n-butenes are in a quantity of at least 80% by weight; optionally ethanol in a quantity ranging from 0 to 10% by weight, the complement to 100 being said gasoline cut.