Patent GB-778249-A (GB)
Title: Grease compositions containing metal phthalamates
IPC: C07C233/12
Filed: 1954-12-24
Abstract: Metal salts of mono-amides of iso- or terephthalic acids, which amides carry a hydrocarbon substituent attached to the nitrogen atom of the amide group, are employed as thickeners in lubricating greases (see Group III).  The metal salts may be prepared by reacting a primary amine with an ester of iso-or terephthalic acid and neutralizing the resulting product with the desired metal oxide or hydroxide.  The metal terephthalomates may be prepared by first treating a diester of terephthalic acid (e.g. dimethyl terephthalate) with a non-aqueous solution of a metallic base (e.g. potassium hydroxide in absolute alcohol) to hydrolyse one of the ester groups, forming a monometal salt of an ester of terephthalic acid.  This salt, or the monoester itself, is treated with thionyl chloride to form the monoacid chloride of the terephthalic acid ester.  The acid chloride is treated with a primary amine to form the monoester of a terephthalamic acid and the ester is treated with a metal oxide or hydroxide to form the desired salt.  In examples describing the preparation of esters of terephthalamic acids, (1) dimethyl terephthalate is saponified with alcoholic potash to produce the potassium salt of monomethyl terephthalate, this salt is decomposed with sulphuric acid to produce monomethyl terephthalate, this monoester is reacted with thionyl chloride to produce the monomethyl ester monoacid chloride of terephthalic acid (methyl terephthaloyl chloride) and this acid chloride is reacted with "octadecylamine" (a commercial mixture of amines consisting mainly of octadecylamine, but also containing hexadecylamine and octadecenylamine) to produce the methyl ester of N-"octadecyl" terephthalamic acid, (2), (3) and (4) the methyl terephthaloyl chloride is reacted with "decylamine" (a commercial mixture of amines consisting mainly of decylamine, but also containing octylamine and dodecylamine) "tallow amine" (a mixture of octadecanoylamine and hexadecanoylamine) or commercial octadecylamine to produce the methyl esters of terephthalamic acids, (6) and (7) potassium methyl terephthalate is reacted with phosphorus trichloride and n-butylamine or aniline to produce methyl, N-butyl or N-phenyl terephthalamate and (7) the methyl N-"octadecyl" terephthalamate of (1) is reacted with n-octadecanol in presence of sodium methylate to produce octadecyl N-"octadecyl" terephthalamate. In examples of the preparation of free phthalamic acids, (15) dimethyl terephthalate is reacted with "octadecylamine" to produce a mixture of unchanged dimethyl terephthalate, methyl N-"octadecyl" terephthalamate and the diamide of terephthalic acid, this mixture reacted with potassium hydroxide, filtered, acidified and the N-"octadecylterephthalamic acid removed by extraction with hot toluene and (16) monoethyl isophthalate is reacted with thionyl chloride to produce ethyl isophthaloyl chloride, which is reacted with "octadecylamine" to produce N-"octadecyl" isophthalamic acid. In an example of the preparation of a metal salt of a phthalamic acid, (8) the methyl N-"octadecyl" terephthalamate of (1) is reacted with barium hydroxide octahydrate to produce barium di-(N-"octadecyl" terephthalamate).ALSO:A lubricating grease comprises a major proportion of lubricating oil and a thickening agent which is a metal salt of a monoamide of iso- or tere-phthalic acid which preferably carries a hydrocarbon radicle attached to the nitrogen atom of the amide group.  The lubricating oil may be mineral oil, or oil derived from coal, or alkylene polymer, a polymerized alkylene oxide or ester or ether thereof, an alkyl benzene, an ester of a dicarboxylic acid (e.g. dibutyl or dihexyl adipate, di - 2 - ethylhexyl sebacate or di - n - hexyl fumarate polymer), an ester of an acid of phosphorous, or an organic silicon compound (e.g. a tetra - alkyl silicate, a polysiloxane or a polysiloxy glycol).  The metal salt may be a salt of a metal of Groups I-IV of the Periodic Table and lists of suitable metal salts are given. The lubricating grease may contain additional ingredients such as oxidation inhibitors (e.g. dihydroxyanthraquinones or metal organo - dithiophosphates), rust inhibitors (e.g. metal petroleum sulphonates), lubricating agents (e.g. aromatic phosphates), colour correctors and stringiness agents. The metal salt may be added to the lubricating oil or may be formed in situ.  When alkylene oxide polymers or organic silicon compounds are employed as the lubricating oil, the metal salt may be first used to gel a volatile hydrocarbon solvent (e.g. toluene), or a mixture of a a volatile hydrocarbon solvent and a volatile alcohol (e.g. a mixture of petroleum thinners and ethyl alcohol), the lubricating oil then added and the volatile material removed.  In the examples, lubricating greases are described consisting of mineral lubricating oil and (1) sodium, lithium, calcium or barium N - "octadecyl" teraphthalamate (the "octadecyl" radicle being derived from a commercial mixture of amines consisting mainly of octadecylamine but also containing hexadecylamine and octadecenylamine), (2) sodium N - butyl or N - p - tolyl terephthalamate, (3) sodium N - "decyl" terephthalamate (the "decyl" radicle being redived from a commercial mixture of amines consisting mainly of decylamine but also containing octylamine and dodecylamine) or (4) sodium N - "octadecyl" isophthalamate.  In further examples, lubricating greases are described consisting of sodium N - "octadecyl" terephthalamate and di (2 - ethylhexyl) sebacate, poly (methylphenyl) siloxane or tetra (2-ethylhexyl) silicate.