Abstract: A process for oligomerising olefins in an organic feed containing at least one olefin comprises two steps with different types of catalysis. The cut to be treated containing at least one olefin (Cn) is introduced via line 1 into a reaction zone R1 where in a first step it undergoes catalytic oligomerisation, either of a liquid phase homogeneous type, or heterogeneous with a solid support. The effluent produced is sent via line 2 to a heat exchanger E1 traversed by a cold liquid. The effluent is thus cooled before being sent via line 3 to a second reaction zone R2 where it undergoes catalytic oligomerisation in a liquid-liquid two-phase medium. After reaction, the effluent is fed via line 4 to a zone L1 where it is washed. After washing, the hydrocarbon fraction is sent via line 5 to separator S1.

Abstract: A process for synthesising hydrocarbons from synthesis gas in the presence of a catalyst essentially constituted by a Raney metal alloy dispersed in a liquid phase is described in which the catalyst comprises at least 60% by weight of at least one metal selected from metals from groups 8, 9 and 10, and optionally at least one additional element selected from alkali metals and metals from groups 4, 5, 6, 7, 8, 9, 10 and 11.