Abstract: A detergent additive for lubricating oils is prepared by reacting an alkyenolsulfide with an oxide or hydroxide of a earth-alkali metal and carbonating the reaction product with carbon dioxide, the reaction being carried out in the presence of a promoter, selected in the class of the organic nitrogen compounds, and possibly of a co-promoter; the temperature and the time of the reaction are depending on whether the co-promoter is present. The resulting product shows improved detergency and flow-ability properties.

Abstract: A dispersing additive for lubricating oils and the related preparation process are disclosed, consisting of a mixture of polyfunctional compounds of the type resulting from the process according to which an olefin polymer is condensed with an unsaturated carboxylic acid, and the condensation product is reacted with an amine, the process being improved in that the condensing step is carried out in the presence of an olefin derivative having a relatively short chain and the condensation product, before being reacted with the amine, is added with a fatty acid and then partially esterified with a polyhdyroxylated compound.

Abstract: In a process for the preparation of detergent additives for lubricant oils, of the type in which an alkylphenolsulfide is neutralized with an oxygen containing compound of an alkaline earth metal and carbonated with carbon dioxide, the process and particularly the neutralization step is carried out in the presence of a promotor selected from NH.sub.3 and NH.sub.4 OH and a co-promoter which is a short chain alcohol having not more than 5 carbon atoms.