A process for the dehydration of a hydrocarbon feed containing mercaptans and H 2 S, in which the following steps are carried out: a) prewashing of said feed with caustic soda diluted to between 1% and 10% in a prewash column, b) liquid-liquid extraction of the effluent leaving the head of the prewash column of step a) using caustic soda diluted to between 10% and 20% by weight, producing a solution of caustic soda charged with mercaptides, and a desulphurized product, c) mixing said solution of caustic soda charged with mercaptides with a hydrocarbon, d) oxidizing said mixture obtained from step c) with the aid of an injection of air by homogeneous phase catalysis, producing a polyphase mixture containing disulphides, e) separating said polyphase solution containing disulphides into a gas phase, an aqueous phase containing caustic soda and an organic phase containing the disulphides, f) extracting said disulphides contained in the aqueous solution containing caustic soda obtained during step e) with a hydrocarbon in order to obtain a mixture containing caustic soda which is free from disulphides, and said hydrocarbon, g) decanting said mixture obtained from step f) in order to recover regenerated caustic soda which is free from disulphides on the one hand, and from said hydrocarbon on the other hand, h) recycling said regenerated caustic soda obtained from step g) to the liquid-liquid extraction column of step b), i) washing the desulphurized product obtained in step b) in a water scrubbing column in order to obtain a scrubbed effluent, j) drying the scrubbed effluent obtained from step i) in a drying column filled with solid caustic soda in the form of pellets in order to obtain a dehydrated product on the one hand and a solution of caustic soda on the other hand, k) collecting said caustic soda solution resulting from step j) and recycling part or all of said solution to the liquid-liquid extraction step b). a) prewashing of said feed with caustic soda diluted to between 1% and 10% in a prewash column, b) liquid-liquid extraction of the effluent leaving the head of the prewash column of step a) using caustic soda diluted to between 10% and 20% by weight, producing a solution of caustic soda charged with mercaptides, and a desulphurized product, c) mixing said solution of caustic soda charged with mercaptides with a hydrocarbon, d) oxidizing said mixture obtained from step c) with the aid of an injection of air by homogeneous phase catalysis, producing a polyphase mixture containing disulphides, e) separating said polyphase solution containing disulphides into a gas phase, an aqueous phase containing caustic soda and an organic phase containing the disulphides, f) extracting said disulphides contained in the aqueous solution containing caustic soda obtained during step e) with a hydrocarbon in order to obtain a mixture containing caustic soda which is free from disulphides, and said hydrocarbon, g) decanting said mixture obtained from step f) in order to recover regenerated caustic soda which is free from disulphides on the one hand, and from said hydrocarbon on the other hand, h) recycling said regenerated caustic soda obtained from step g) to the liquid-liquid extraction column of step b), i) washing the desulphurized product obtained in step b) in a water scrubbing column in order to obtain a scrubbed effluent, j) drying the scrubbed effluent obtained from step i) in a drying column filled with solid caustic soda in the form of pellets in order to obtain a dehydrated product on the one hand and a solution of caustic soda on the other hand, k) collecting said caustic soda solution resulting from step j) and recycling part or all of said solution to the liquid-liquid extraction step b).