Preparation of olefin by alcohol dehydration, and uses thereof for making polymer, fuel or fuel additive

A C5 olefin mixture containing:

• (i) at least 50 wt % of an olefin mixture comprising (i-a) 2-methyl-but-2-ene, (i-b) 2-methyl-but-1-ene and (i-c) 3-methyl-but-1-ene, and
• (ii) (ii-a) one C4 olefin chosen among 1-butene, 2-butene, 2-methylpropene, and/or (ii-b) one C6 olefin chosen among 1-hexene, 2-hexene, 3-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2,3-dimethyl-2-butene, cyclohexene, 2-methyl-2-pentene, 3-methyl-2-pentene, 3,3-dimethyl-1-butene, 1-methyl-cyclopentene, 3-methyl-cyclopentene, 4-methyl-cyclopentene, methylene-cyclopentane,
• the C5 olefin mixture optionally comprising (ii-c) one C15 hydrocarbon,
• the C5 olefin mixture being obtained by a process comprising the steps of:
• a) providing an initial composition comprising at least 20 wt % of a C5 branched alcohol based on the total weight of the initial composition, and
• b1) dehydrating the initial composition and separating the obtained dehydrated composition to provide a first stream enriched in C2 olefins, a second stream enriched in C5 olefins, and a third stream containing heavier compounds, the C5 olefin mixture being recovered from the second stream enriched in C5 olefins, or
• b2) separating the initial composition to provide a first stream enriched in C2 alcohols, a second stream enriched in C5 alcohols, and a third stream enriched in heavier compounds, and dehydrating the second stream enriched in C5 alcohols to obtain the C5 olefin mixture,
• wherein the initial composition is obtained by fermentation of biomass feedstocks, and
• wherein the initial composition comprises at least 20 wt % Cs branched alcohol, at least 1 wt % ethanol, at least 0.1 wt % n-propanol, at least 1 wt % C4 alcohols, at most 1.5 wt % esters and at least 5 wt % water, based on the total weight of the initial composition.