Synthetic lubricating oils having a predetermined alkylaromatic structure are prepared from a mixture of mono- or dialkenyl benzene with an aliphatic olefin by free-radical reaction in the presence of ditertiary-butyl peroxide, for example. Equivalent napthalene derivatives may be substituted for the dialkenyl benzene. The oils that are formed exhibit a high Viscosity Index, and a low pour point. The viscosity of the synthetic lube stock produced may be controlled by changing the amount of peroxide used.
Synthetic oil that contains wholly or partly of dialkylbenzenes and/or partially or totally hydrogenated dialkylbenzenes. The synthetic oil according to the invention can also be used as an oil base or oil base additive and comprises at least one dialkylbenzene and/or at least one partially or totally hydrogenated dialkylbenzene and meets the general chemical formula: in which R1 and R2 represent alkyl groups and A is a benzene core and/or a cyclohexane core and/or a cyclohexene core and/or a cyclohexadiene core and is characterized in that it contains between 1 and 20% by weight or ortho isomers and in that at least one of the alkyl groups is attached for the most part to group A by carbon 2 of the aliphatic chain. The two alkyl groups are preferably attached for the most part to group A by carbon 2 of the aliphatic chain.
Novel methods for the preparation of modified poly .alpha.-olefins, and compositions prepared by the novel methods are disclosed. The modified poly alpha-olefins of the present invention are useful as base fluids or additives in synthetic lubricants.
A lubricating oil composition comprises an alkylnaphthalene which has one or two alkyl groups each having from 8 to 30 carbon atoms, and at least one member selected from benzo(b)thiophene and derivatives thereof, and naphthalenethiol and derivatives thereof. The composition has good oxidative stability.
