Process for the production of petroleum sulfonate

Claim 1

A process for producing monovalent cation-containing petroleum sulfonates which are capable of forming a micellar dispersion when admixed with mixtures of hydrocarbon and aqueous medium, the process comprising reacting in a back-mix tubular reactor comprised of a pump, a reaction zone and heat exchanger: 1. a hydrocarbon gas oil feedstock having an average molecular weight of about 250 to about 700 and an aliphatic to aromatic proton ratio of about 5 to about 50 moles per mole, and wherein at least about 30% of the feedstock molecules contain an aromatic nucleus, the aliphatic to aromatic proton ratio of the feedstock molecules containing the aromatic nucleus being about 3 to about 20 moles per mole, 2. with an ethylene dichloride (EDC) solution containing about 0.1 to about 0.3 part of liquid SO 3 per part of the EDC and wherein the weight ratio of the SO 3 to the gas oil feedstock is about 0.05 to about 0.3 part of SO 3 per part of gas oil feedstock, and wherein the hydrocarbon gas oil feedstock plus recycled reaction products stream is under turbulent flow and the SO 3 /EDC stream is under turbulent flow, but wherein the velocity ratio of the hydrocarbon gas oil feedstock plus recycled reaction products stream to the SO 3 /EDC stream is at least 4:1, respectively, 3. withdrawing about 1 part of the reaction products resulting from reaction of 1 and 2 for about 1 to about 6 parts of the reaction products recycled in the reactor, and neutralizing this portion of the reaction products to a pH of about 5 to about 9 with an aqueous basic solution containing a monovalent cation, 4. removing substantially all of the EDC from the neutralized reaction products to obtain an unextracted sulfonate mix, 5. contacting the unextracted sulfonate mix with sufficient amounts of an aqueous alcohol solution containing an alcohol which has sufficient solubility in the mixture to cause the resulting mixture to settle into at least a raffinate phase, an extract phase, and a brine phase. 6. separating the raffinate phase, the raffinate phase containing mostly unreacted gas oil, alcohol and water, 7. separating the brine phase, and 8. separating the extract phase, the extract phase containing alcohol, water, and the petroleum sulfonate product, and removing a major portion of the alcohol and water from the extract phase to obtain the desired monovalent-containing petroleum sulfonates.