摘要:
A composition comprises a sulphur free reaction product of: (a)(i) a hydrocarbyl substituted aromatic compound containing an acidic group selected from the group consisting of a carboxylic group, a hydroxyl group and mixtures thereof; and (a)(ii) an organic nitrogen-containing base reacted with the acidic group. The composition is obtained by a preparatory process and is useful in a method for lubricating an internal combustion engine to include where the lubricant has reduced levels of sulphur, phosphorus and sulphated ash.