| abstract |
This invention relates to a cyclic compound comprising m units of formula (Ia) and n units of formula (Ib) joined together to form a ring, wherein each Y is a divalent bridging group which may be the same or different in each unit; R0 is H or an alkyl group of 1 to 6 carbon atoms; R5 is H or an alkyl group of 1 to 60 carbon atoms; j is 1 or 2; R3 is hydrogen, a hydrocarbyl or a hetero-substituted hydrocarbyl group; either R1 is hydroxy and R?2 and R4¿ are independently either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl, or R?2 and R4¿ are hydroxyl and R1 is either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl; m is from 1 to 8; n is at least 3, and m + n is 4 to 20. This invention also relates to metal salts of the foregoing compound, especially overbased metal salts. The invention also relates to additive compositions, finished lubricating oil compositions and fuel compositions containing the foregoing compound or metal salt thereof. The invention also relates to a process for making the foregoing compound and salts thereof. |