Process that involves the optimum etherification of a hydrocarbon fraction that contains olefins that have 6 carbon atoms per molecule

A process for the production of ethers from a hydrocarbon feedstock comprising 70 to 100% by weight olefins that contain 6 carbon atoms per molecule, with said olefins containing 30 to 50% of those which are potentially etherifiable and 50 to 70% of those which are directly etherifiable, comprising successively:

• (0) separating the feedstock into a >C.sub.6 hydrocarbon fraction and into a .ltoreq.C.sub.6 hydrocarbon fraction,
• (1) etherifying a portion of the etherifiable olefins that are contained in the .ltoreq.C.sub.6 hydrocarbon fraction, in the presence of at least one alcohol that has 1 to 4 carbon atoms per molecule and of an etherification catalyst, in a first etherification zone to obtain an etherified effluent,
• (1') washing with water a portion of the etherified effluent of (1) in a washing zone that makes it possible to obtain a water and alcohol effluent and a hydrocarbon effluent,
• (2) separating, in a separation zone, a portion of the hydrocarbon effluent of
• (1'), into an ether effluent and into a hyrocarbon and alcohol effluent,
• (2') washing with water a portion of the hydrocarbon and alcohol effluent of (2) in a washing zone that makes it possible to obtain a water and alcohol effluent and a hydrocarbon effluent,
• (3) isomerizing a portion of potentially etherifiable olefins that are included in the hydrocarbon effluent of (2') in an isomerization zone, in the presence of an isomerization catalyst that makes it possible to obtain an isomerization effluent that comprises in part etherifiable olefins,
• (4) etherifying, in a second etherification zone, in the presence of at least one alcohol that has 1 to 4 carbon atoms per molecule and an etherification catalyst, a portion of the etherifiable olefins that are included in said isomerization effluent of (3) to obtain an etherified effluent.