Process for the production of overbased calixarates

A process for the production of an overbased metal salt which comprises reacting at elevated temperature:

• (A) either (i) available for reaction with metal base, (ii) a low based metal calixarate, (iii) a neutral metal calixarate or an non-sulphurized overbased metal salt of a sulphur-free calixarene having a substituent hydroxyl group or groups available for reaction with a metal base,
• (B) a metal base added either in a single addition or in a plurality of additions at intermediate points during the reaction,
• (C) a solvent comprising either:
• (C.sub.1) either (i) a polyhydric alcohol having 2 to 4 carbon atoms, (ii) a di- (C.sub.3 or C.sub.4) glycol, (iii) a tri- (C.sub.2 -C.sub.4) glycol or (iv) a mono- or poly-alkylene glycol alkyl ether of the formula:
• R.sup.9 (OR.sup.10).sub.f OR.sup.11 (III)
• wherein in the formula (III) R.sup.9 is a C.sub.1 to C.sub.6 alkyl group, R.sup.10 is an alkylene group, R.sup.11 is hydrogen or a C.sub.1 to C.sub.6 alkyl group and f is an integer from 1 to 6, either alone or in combination with either (C.sub.2) a hydrocarbon solvent or C(3) either (i) water, (ii) a C.sub.1 to C.sub.20 monohydric alcohol, (iii) a C.sub.1 to C.sub.20 ketone, (iv) a C.sub.1 to C.sub.10 carboxylic acid ester or (v) an aliphatic, alicyclic or aromatic C.sub.1 to C.sub.20 ether, or, (C.sub.4) a C.sub.1 to C.sub.4 monohydric alcohol, in combination with a hydrocarbon solvent (C.sub.2), and
• (D) carbon dioxide added subsequent to each addition of component (B).