Abstract: The present invention is directed to a novel process for making Group II metal overbased sulfurized alkylphenols, which process uses alkylene carbonate as both a source of carbon dioxide and alkylene glycol. In particular, under the reaction conditions using ethylene carbonate, carbonation time is reduced to about one quarter the time taught in the prior art to make Group II metal overbased sulfurized alkylphenol compositions. The present invention is also directed to a detergent-dispersant additive composition comprising a Group II metal overbased sulfurized alkylphenols, wherein the Group II metal overbased sulfurized alkylphenols have a reduced color as measured by ASTM Test No. D 6045 and an increased hydrolytic stability as measured by a modified ASTM Test No. 2619.