Method for reducing mercaptans in hydrocarbons

A method for selectively treating a crude oil containing mercaptans while retaining other non-mercaptan sulfur species in the crude oil feed, comprising:

• combining a sodium hypochlorite solution with a least a base to form a treatment solution having a pre-select pH;
• contacting a crude oil feed which is not a petroleum distillate with the treatment solution comprising the sodium hypochlorite at a pre-select pH under intimate contact conditions sufficient for the hypochlorite to oxidize the mercaptans generating a treated crude oil having a reduced concentration of mercaptans of less than 50 ppm by weight and a first concentration of chloride and a spent treatment solution and wherein the majority of mercaptans are removed by the treated crude oil and the majority of non-mercaptan sulfur species remain in the treated crude oil;
• recovering the spent treatment solution and the treated crude oil;
• separating the spent treatment solution and the treated crude oil to recover the spent treatment solution and the treated crude oil as separate streams;
• contacting the treated crude oil stream with a caustic solution under mixing conditions sufficient to generate a spent alkaline solution and an upgraded crude oil having less than 50 ppm by weight, mercaptan and less than 10 ppm by weight organic chloride;
• separating the spent alkaline solution and the upgraded crude oil;
• treating the spent treatment solution to generate a brine solution comprising at least 99 wt. % as sodium chloride in solution;
• regenerating the brine solution to form a hypochlorite stream for use in the treatment solution.