Patent ID: 7094922

Claim:
A process for the production of low base number calcium sulfonates comprising: a. preparing a sulfonic acid-oil solution by adding about 1 to about 20 volumes of a miscible solvent to a sulfonic acid-oil feedstock, centrifuging said solution and removing dissolved or entrained SO 2 or SO 3 via stripping if present; b. mixing the sulfonic acid-oil solution with about 1 to about 5 moles of water per mol of sulfonic acid and about 1 to about 10 moles of calcium hydroxide per mole of sulfonic acid to provide a reaction mixture; c. heating the reaction mixture to a temperature in the range of about 40° C. to about 200° C.; d. separating excess calcium hydroxide from the heated-reaction mixture to produce a reaction product comprising solvent, oil, and calcium sulfonate; e. removing the solvent from the reaction product to produce an intermediate product comprising oil and calcium sulfonate; f. optionally concentrating the intermediate product by removing at least a portion of the oil to produce a concentrated product; and g. recovering the intermediate product and/or concentrated product, wherein the product is essentially chloride free calcium sulfonate in oil.