Patent GB-753339-A (GB)
Title: Preparation of metal carboxylates and lubricating greases containing them
IPC: C07C51/295
Filed: 1953-11-09
Abstract: Metal salts of aliphatic carboxylic acids are obtained by a process comprising heating a branched chain or straight chain aliphatic aldehyde containing at least 10 carbon atoms with caustic alkali at a temperature in the range 350-620 DEG  F. Oxo-aldehydes having 10 or more carbon atoms are the preferred starting materials.  Lower aldehydes may be used if they are first subjected to an aldol condensation to produce aldols containing 10 or more carbon atoms. The salts obtained are useful as grease thickeners and may be prepared in the lubricating oil itself.  To prevent the alkali from settling in the lubricating oil-aldehyde mixture it is desirable to add a suspending agent.  Suitable suspending agents are those which also serve as grease thickeners, e.g. sodium soaps of C10 or higher aliphatic acids, silica gel, carbon black, bentones and Attapulgus clay modifications.  If a soap is used as settling agent it is also advisable to have present an alkali metal salt of a C9 or lower acid. These salts may be prepared in situ by neutralization of the corresponding acids in the aldehyde-oil mixture with alkali added in amounts sufficient for the neutralization and for the subsequent fusion.  Suitable higher acids are, for example, hydrogenated fish oil acids and C12-C22 naturally occurring acids of animal or vegetable origin and suitable lower acids are acetic, furoic and acrylic acids.  Elevated pressures may be used.  In the examples (a) octadecenyl aldehyde prepared by oxonation of di-isobutylene followed by aldolization of the oxo-nonylaldehyde is heated with caustic soda in the presence of hydrogenated fish oil and glacial acetic acid; phenyl-alpha-naphthylamine is then added as oxidation inhibitor to give a lubricating grease.ALSO:Lubricating greases are obtained by incorporating into lubricating oils a grease thickener obtained by fusing an aliphatic aldehyde having at least 10 carbon atoms with caustic alkali at a temperature in the range 350 DEG -620 DEG F. to form the metal salt of the acid corresponding to the aldehyde.  The aldehyde is preferably fused with the alkali in the lubricating oil base. Oxoaldehydes are preferred as starting materials.  Lower aldehydes may also be use provided they are first subjected to aldolization to produce aldols having at least 10 carbon atoms. If the alkali fusion is carried out in situ it is desirable to add a suspending agent which may also serve as a grease thickener, e.g. sodium soaps of higher fatty acids having 10 or more carbon atoms, silica gel, carbon black, bentones and Attapulgus clay. If a sodium salt of a higher fatty acid is used it is advisable to add also an alkali metal salt of a lower fatty acid.  The base oil used during the fusion process should be a mineral lubricating oil but after the fusion is completed synthetic lubricating oils, such as dibasic acid esters, polyglycol type synthetic oils, esters of dibasic acids and polyhydric alcohols as well as alkyl silicates, carbonates, formals and acetals may be used alone or in addition to mineral lubricating oil to bring the grease to the desired consistency.  Other thickeners, anti-oxidants, corrosion inhibitors and viscosity index improvers may also be added.  In the examples, (a) a grease is obtained by heating octadecenyl aldehyde, hydrogenated fish oil acids glanal acetic acid, caustic soda, and naphthenic lubricating oil; an oxidation inhibitor, phenyl alphanaphthylamine being added after heating and (b) the grease prepared as in (a) is mixed with a highly paraffinic lubricating grade mineral oil to give a semi-fluid grease which is then homogenized.