Abstract: The invention relates to a process for preparing jet fuel or jet fuel precursors which comprises the treatment of a charge derived from biomass, the said charge comprising at least one compound chosen from terpenes of formula [CH2?C(CH3)CH?CH2]n, in which n is an integer of from 2 to 12, the carbon chain of which is linear, cyclic or branched, or cyclic or branched terpenes as defined previously, which have been chemically modified by oxidation and/or rearrangement of the carbon backbone, the said process comprising a cycloaddition step (i) followed by a cracking and hydrogenation step (ii).

Abstract: The present invention is a process to upgrade light naphthas comprising branched paraffins and their use as a feedstock in a steam cracking unit, said light naphthas consisting essentially of 90 to 100% by weight of hydrocarbons having at least 5 and up to 8 carbon atoms, said process comprising, a) optionally providing an isomerization zone recovered from the gasoline unit of an oil refinery, b) optionally providing a separation zone capable to treat an hydrocarbon stream comprising branched paraffins and normal paraffins to produce a first hydrocarbon stream having a reduced branched paraffins content and an enhanced normal paraffins content and a second hydrocarbon stream having an enhanced branched paraffins content and a reduced normal paraffins content, c) optionally providing a depentanizer, such that at least two of a), b) and c) are present, wherein, the light naphtha is sent to one of a), b) and c), streams are circulating between the various zones a), b) or c), a stream rich in normal paraffi