NOVELTY - Producing alcohols from olefins comprises: (a) contacting mixed olefin stream with dual phase catalyst system to produce mixed alcohol stream, where dual phase catalyst system comprises water soluble acid catalyst and solid acid catalyst, and water soluble acid catalyst is soluble in water and solid acid catalyst is insoluble in water; and (b) dual phase catalyst system is capable of hydrating mixed olefin stream without separation of olefins prior to contacting mixed olefin stream with dual phase catalyst system, where mixed alcohol stream contains many types of alcohols.    USE - The process is useful for producing alcohols which are used in fuel compositions including neat fuel compositions (all claimed), and as octane enhancers.    ADVANTAGE - The process provides alcohols: with increased combustion efficiencies and reduced emissions of harmful gases and airborne soot; which exhibits British thermal unit (BTU) energy content closer to the energy content of gasoline than that of methanol/ethanol based fuels; which is environmental friendly; with low and stable Reid vapor pressure blending characteristics and are less corrosive than methanol/ethanol, thus enabling them to be used by existing storage and transportation facilities; that can be used in existing engines without modifications; and with low toxicity components and readily biodegradable.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a neat fuel composition comprising a mixed butanol fuel having an octane rating suitable for use in combustion or compression engines, where the mixed butanol fuel is produced by the process;    (2) a fuel composition comprising a fuel component with the mixed butanol fuel produced by the process;    (3) producing the fuel composition from olefins, comprising: (a) as above per se; and (b1) combining the mixed alcohol stream with the fuel component to produce the fuel composition, where the fuel component comprises gasoline, diesel, jet fuel, aviation gasoline, heating oil and/or bunker oil; and    (4) the dual phase catalyst system for the production of mixed alcohols from mixed olefins, comprising the water soluble acid catalyst and the solid acid catalyst, where the water soluble acid catalyst is soluble in water and the solid acid catalyst is insoluble in water, the dual phase catalyst system is capable of hydrating the mixed olefin stream without separating the olefins prior to contacting the mixed olefin stream with the dual phase catalyst system and the mixed alcohol stream contains the alcohols.