Patent GB-695570-A (GB)
Title: Improvements in or relating to rust inhibiting compositions
IPC: C10M135/06
Filed: 1950-09-21
Abstract: The invention comprises as new compounds sulphurized mono esters of C12 to C24 unsaturated aliphatic monocarboxylic acids and polyhydroxy aliphatic compounds containing 5 to 6 carbon atoms and having 4 to 6 hydroxyl groups attached to carbon atoms separated from each other by not more than one carbon atom containing no hydroxyl group.  The acid portion of the molecule, before sulphurization, may contain one to two double bonds and the polyhydroxy aliphatic compound may contain various substituent groups such as aldehyde, ketone or ether groups. Suitable polyhydroxy compounds include the hexitols, e.g. sorbitol, mannitol and dulcitol; aldohexoses such as glucose, mannose, fructose and galactose, and the dehydrated products of such compounds such as sorbitan.  Compounds containing a neo carbon atom, e.g. pentaerythritol, may also be used. Suitable unsaturated acids are monoolefinic acids such as oleic acid, elaidic acid and erucic acid; diolefinic acids, such as linoleic acid; and substituted unsaturated acids such as ricinoleic acid.  The esters are formed by reacting the acids and the polyhydroxy compounds under normal esterification conditions using only enough acid to form the mono-ester.  The sulphurization reaction may take place before or after the unsaturated acid is reacted with the polyhydroxy compound and is accomplished by heating the acid or ester in the presence of elementary sulphur. Examples of suitable esters which may be sulphurized are sorbitan monooleate, mannitol monooleate, hexitan monooleate, sorbitan monolinoleate, glucose monooleate, fructose monoerucate, pentaerythritol monooleate, pentaerythritol monoerucate and pentaerythritol monolinoleate.  The sulphurized esters when dissolved in any hydrocarbon solvent are useful as rust-preventing agents.  In the examples sorbitan monooleate, pentaerythritol monooleate were sulphurized by heating with flowers of sulphur.ALSO:The sulphurized C12 to C24 unsaturated aliphatic monocarboxylic acid monoesters of polyhydroxy aliphatic compounds containing 5 to 6 carbon atoms per molecule and having 4 to 6 hydroxyl groups attached to carbon atoms which are separated from each other by not more than one carbon atom containing no hydroxyl group are used as additives to lubricants or as principal components in slushing oils to inhibit rust and corrosion. Suitable polyhydroxy compounds include the hexitols and aldohexoses and their dehydrated products and compounds containing a neo-carbon atom, such as pentaerythritol.  Suitable unsaturated acids include monoolefinic acids, diolefinic acids and substituted unsaturated acids such as ricinoleic acid.  The additives are added to mineral oils in proportions from 0.01 to 10 per cent, preferably in the range 1.0 to 5.0 per cent when used as rust inhibitors in mineral lubricating oils.  Other additives, thickeners, detergents &c. may be present. In the examples sulphurized sorbitan monooleate and sulphurized pentaerythritol monooleate were each added to refined coastal naphthenic oil and to a phenol-treated Mid-continent lubricating oil.