Patent GB-665107-A (GB)
Title: Improvements in mineral lubricating oil compositions
IPC: C10M129/76
Filed: 1948-02-05
Abstract: Metal phenates derived from esters of phenolic acids are employed as ingredients in lubricating compositions (see Group III).  The metal phenates may have the general formula <FORM:0665107/IV (b)/1> where M is a metal, R is an aromatic radicle, X and X1 are each either oxygen or sulphur and R1 is an aromatic, cycloaliphatic or aliphatic radicle, but compounds of this formula having a long-chain aliphatic hydrocarbon group of at least 20 carbons linked to the aromatic nucleus R are excluded.  Magnesium lauryl salicylate is prepared by direct reaction between metallic magnesium and lauryl salicylate, while calcium lauryl salicylate and magnesium iso-amylsalicylate are similarly prepared. Phenates of other alkaline earth metals may also be prepared by this method but aluminium, zinc, cobalt and nickel phenates must be prepared by first preparing the sodium phenate by reaction of metallic sodium with the phenolic ester and then converting the sodium phenate to the phenate of the desired metal by double decomposition.  Lists of suitable phenolic acids to be used in preparing the esters and lists of alcohols and phenols for reacting with the phenolic acids in the preparation of the esters are given. Lists of radicles which may additionally be present in the molecule of the metal phenates are also given.  The Specification as open to inspection under Sect. 91 refers to the use of metal oxides of aromatic esters in which the oxygen of the metal oxide group is directly attached to an aromatic ring.  A list of non-phenolic acids is given, which acids may be reacted p  with phenolic alcohols to give suitable aromatic esters.  This subject-matter does not appear in the Specification as accepted.ALSO:A lubricating composition, especially suitable for use in the crankcase of an internal combustion engine, comprises a major proportion of mineral lubricating oil and a minor proportion of an oilsoluble metal phenate derived from the ester of a phenolic acid.  The use of a metal phenate having a long chain aliphatic hydrocarbon group of at least 20 carbon atoms linked to the aromatic nucleus is excluded.  The metal phenate may (subject to the above exclusion) have the general formula:- <FORM:0665107/III/1> where M is a metal, R is an aromatic radicle, X and X1 are each either oxygen or sulphur and R1 is an aromatic, cycloaliphatic or aliphatic radicle.  Metal phenates specifically mentioned are magnesium lauryl salicylate, calcium lauryl salicylate and magnesium isoamyl salicylate, but phenates of other alkaline earth metals, aluminium, zinc, cobalt and nickel may also be employed.  Lists of suitable phenolic acids to be used in preparing the esters and lists of alcohols and phenols for reacting with the phenolic acids in the preparation of the esters are given. Lists of radicles which may additionally be present in the molecule of the metal phenates are also given.  The metal phenates act as detergents, but where a lubricating composition which also has exceptionally high film strength is desired, the metal phenates may be employed in conjunction with extreme pressure addition agents such as sulphur or halogen compounds. Alternatively, a halogen such as chlorine may be included in the molecule of the metal phenates so that they impart both high detergency and high fibre strength to the lubricating compositions.  The Specification as open to inspection under Sect. 91 refers to lubricating compositions prepared by the addition to a mineral lubricating oil of minor amounts of oil-soluble metal oxides of aromatic esters which oxides are of the type in which the oxygen of the metal oxide group is directly attached to an aromatic ring. A list of non-phenolic acids is given, which acids may be reacted with phenolic alcohols to give suitable aromatic esters. This subject-matter does not appear in the Specification as accepted.