Method for oligomerisation in a gas/liquid reactor comprising a central duct

A process for the oligomerization of a gaseous olefinic feedstock, said process comprising:

• performing oligomerization of the gaseous olefinic feedstock in a gas/liquid reactor at a temperature of between 30 and 200° C., and a pressure of between 0.1 and 10.0 MPa, in the presence of a catalytic system comprising at least one metal precursor,
• wherein said gas/liquid reactor has a lower part and an upper part and comprises:
• a reactor chamber (1), of elongated shape along a vertical axis, having a lower zone and an upper zone,
• a gas injection device (3),
• a liquid injection device (11),
• a central pipe (12) positioned on the vertical axis inside said chamber in a lower zone of said chamber;
• said central pipe delimiting a central flow zone that is capable of permitting a descending flow and an outer flow zone that is capable of permitting an ascending flow, and said central pipe having an upper part and a lower part,
• in which the gas injection device is positioned in the upper part of said central pipe and the liquid injection device is positioned in the lower zone of the reactor chamber so as to be able to entrain the injected gas in the direction of the lower part of the reactor, from the descending central zone to the ascending outer zone.