摘要 |
A process is disclosed for overbasing a substrate comprising mixing a composition comprising said substrate, water, a phenol containing up to three aliphatic carbon atoms, a source of magnesium and a carbonating agent, under reaction conditions to form a magnesium overbased substrate, said water being retained in said composition throughout the overbasing reaction, the weight ratio of the water to magnesium being about 10:1 to about 1:5. A magnesium overbased substrate made by the foregoing process is disclosed. Concentrates and lubricating compositions containing the foregoing magnesium overbased substrate are also disclosed.
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