[sə′lü‚tīz·ər ′stēm rē′jen·ə·rəd·iv ‚prä·səs] (chemical engineering) A petroleum refinery process used to extract mercaptans from gasoline or naphtha; uses solutizers (potassium isobutyrate or potassium alkyl phenolate) in strong potassium hydroxide solution as the selective solvent.