GB697461A - Improved lubricant additive - Google Patents

Abstract

In the preparation of lubricating oil additives, by the reaction of a barium, calcium, strontium, magnesium or zinc, mono- or poly-alkyl phenate with elemental sulphur, the reaction product is freed from unreacted alkyl phenols and other volatile matter by steam distillation below the decomposition temperature of the product, preferably at 120-180 DEG C., e.g. at 135-160 DEG C. In preferred modifications a mono-alkyl phenol, preferably a p-alkyl phenol, is reacted with an alkaline earth metal oxide, hydroxide or hydrated oxide in an inert diluent, non-volatile in steam, such as a lubricating oil and in the presence of a minor proportion of a C8-C20 saturated aliphatic alcohol, such as cetyl or stearyl alcohol; sulphur is added in an amount exceeding 2 1/2 times the amount required in the finished product and when sulphurization is complete the mixture is steam distilled at 120-180 DEG C., preferably at 135-160 DEG C, until the residual alkyl phenol is substantially all removed or is below the solubility limit in the mixture at O DEG C., the reaction product being blown with carbon dioxide either before during or after steam distillation. A preferred product is a sulphurized barium alkyl phenol containing between 3 and 4 per cent of sulphur and between 7 and 10 per cent of barium. In an example, p-tert-octyl phenol is dissolved in a mineral lubricating oil together with a minor proportion of mixed cetyl/stearyl alcohol and the mixture is blown with nitrogen and mixed with barium oxide at 350-390 DEG F., followed by the addition of sulphur at 300-350 DEG F., carbon dioxide is then blown in and the mixture is steam distilled at 250-350 DEG F. to remove volatile matter. Specifications 586,841, 599,729 and 600,825 are referred to.ALSO:A lubricating composition comprises a lubricating oil, preferably a mineral lubricating oil, and a minor proportion of an additive obtained by reacting a barium, calcium, strontium, magnesium or zinc, mono- or polyalkyl phenate such as barium p-iso octyl phenate with sulphur and removing free alkyl phenols or other volatile matter by steam distillation, (see Group IV(b)). Preferably the composition comprises a mineral oil and up to 15 per cent, suitably between 0.5 and 6 per cent, e.g. 2-3 per cent of the additive. The sulphurization reaction is conveniently carried out using mineral oil as an inert solvent and in the presence of a C8-C20 aliphatic alcohol such as cetyl or stearyl alcohol, in which case the additive is obtained as a concentrate in solution in mineral oil. An example describes the preparation of a concentrate containing 40 per cent of the additive derived from barium p-tertiary octyl phenate and sulphur in mineral oil. Specifications 586,841, 599,729 and 600,825 are referred to.