Phenate Detergent Preparation

A method of making a sulphurised calcium phenate detergent comprising the steps of

• (i) reacting one or more alkyl phenol materials comprising hydrogenated distilled cashew nut shell liquid with a calcium salt and sulphur in the presence of a promoter and of a process solvent to obtain a reaction mixture;
• (ii) reacting the reaction mixture with additional amounts of calcium salt and promoter, and with a co-surfactant, and then subjecting the reaction mixture to carbonation;
• and optionally
• (iii) further carbonating the reaction mixture to obtain overbased sulphurised calcium phenate;
• wherein the co-surfactant is selected from a phenol or alkyl phenol or methylene bridged alkyl phenol;
• or a hydrocarbyl substituted anhydride or succinic anhydride.