PREPARATION OF OVERBASED SULFONATES

1,154,370. Carbonate dispersion in oil. ESSO RESEARCH & ENG. CO. 3 Aug.. 1967 [17 Aug., 1966], No. 35658/67. Heading C1A. [Also in Division C5] A dispersion of calcium carbonate is prepared by contacting a mixture of diluent hydrocarbon oil, oil soluble hydrocarbon sulphonic acid or a metal salt thereof, calcium hydroxide and a promoter with at least the stoichiometric amount of carbon dioxide required to convert to colloidally dispersed calcium carbonate all the calcium hydroxide not used for the formation of sulphonate salt whilst maintaining the water content of said mixture at 0À1 to 1À75% by weight. The specified water content can be maintained by removing 60-80% of the water formed in the reaction by carrying it off with excess carbon dioxide or inert gas, by boiling at 400 ‹F. or by reducing the pressure above the mixture. Sulphonates which can be employed include those of Na, Li, K, Fe, Al, Mn, Cd, and the alkaline earth metals. The starting sulphonates may be either neutral or overbased to a base number of 30-40 and may be derived from either petroleum sulphonic acids of from synthetic sulphonic acids which may be alkane, aromatic, alkaryl and aralkyl sluphonic acids having molecular weights of 400-1200. The promoter is generally used in amounts of 0À3 to 8% by weight of the reaction mixture and is exemplified by aliphatic monohydric and polyhydric alcohols, amines and alkanol amines; an auxiliary promoter such as an alkyl phenol or sodium xylene sulphonate may be used. Fatty acids having 12-24 carbon atoms can be used in amounts of 3-25% by weight of the reaction mixture as stabilizers.