Patent GB-497385-A (GB)
Title: A process for the manufacture of lubricants
Filed: 1937-08-26
Abstract: High pressure lubricants are prepared by adding to mineral lubricating oils or greases from 1 to 10 per cent by weight of organic compounds the molecules of which contain at least two benzine rings to which at least two hydroxy or carboxylic groups or at least one hydroxy group and one carboxylic group are directly connected, and which are either sulphur free or contain sulphur exclusively in a non-reactive or practically non-reactive form, i.e. in the form of a hetero atom in ring systems.  The organic compounds added may be di- or tri-phenyl methane derivatives or azo colourants derived from diazotized benzidine. In examples, the mineral oil is a Venezuelan brightstock and the addition is (1) methylene di-b -naphthol; (2) 1-oxy-2-naphthoic acid; (3) the reaction product of resorcinol and formaldehyde; (4) methylene disalicylic acid; (5) methylene digallic acid; (6) aurine; (7) aurine tricarboxylic acid; (8) resaurine, or (9) products obtained by coupling diazotized benzidene with phenol, resorcinol or salicylic acid.  Specifications 7775/07, [Class 91], 376,818, and 432,121 are referred to.  Samples have been furnished under Sect. 2 (5) of Western brightstock admixed with (1) methylene dibenzoic acid; (2) 1-5-naphthalene dicarboxylic acid and (3) a mixture of anthraquinone dicarboxylic acid 2,6 with anthraquinone dicarboxylic acid 2,7.  Methylene di-b -naphthol is prepared by mixing b -naphthol with concentrated hydrochloric acid, adding a solution of formaldehyde, shaking with ether, separating the ether layer, filtering and evaporating off the ether.  Methylene di-benzoic acid is prepared by dissolving benzoic acid in concentrated sulphuric acid and stirring in a mixture of a solution of formaldehyde and concentrated sulphuric acid.  After standing for four days, the mixture is poured on to ice and the brown mass which separates is boiled with an aqueous solution of sodium acetate and filtered.  The filtrate is acidified with hydrochloric acid, when methylene di-benzoic acid is precipitated as a yellow substance.  According to the Specification as open to inspection under Sect. 91, the addition may comprise oenanthylidene disalicylic acid, oil-soluble compounds obtained by polymerizing or condensing aliphatic hydrocarbons with organic compounds the molecules of p  which contain at least two isocarbocyclic rings of six atoms to which at least two hydroxy or carboxylic groups or at least one hydroxy and one carboxylic group are connected direct, or the product obtained by condensing salicylic and with a distillate obtained by cracking paraffin wax in the vapour phase.  This subject-matter does not appear in the Specification as accepted.ALSO:Methylene di-b -naphthol is prepared by mixing b -naphthol with concentrated hydrochloric acid, adding a solution of formaldehyde, shaking with ether, separating the ether layer, filtering and evaporating off the ether.  Methylene di-benzoic acid is prepared by dissolving benzoic acid in concentrated sulphuric acid and stirring in a mixture of a solution of formaldehyde and concentrated sulphuric acid.  After standing for four days, the mixture is poured on to ice and the brown mass which separates is boiled with an aqueous solution of sodium acetate and filtered.  The filtrate is acidified with hydrochloric acid, when methylene di-benzoic acid is precipitated as a yellow substance.