Patent GB-915161-A (GB)
Title: Improvements in or relating to synthetic lubricants
IPC: C07C69/34
Filed: 1959-02-03
Abstract: Lubricating compositions comprise esters represented by the general formula R1-OOC-R-COO-R2 wherein the group OOC-R-COO is derived from a dibasic carboxylic acid in which R is a hydrocarbon radical and wherein R1 and R2, which may be the same or different, are radicals each derived from a neopentyl polyhydric alcohol the or each hydroxyl group of the neopentyl polyhydric alcohol, other than that used to form the ester linkage with said dibasic carboxylic acid, being substituted by an alkoxy radical containing 1 to 12 carbon atoms or by a saturated aliphatic carboxylic acid radical containing 4 to 18 carbon atoms or by a mononuclear aromatic carboxylic acid not substituted with an open-chain aliphatic group containing a quaternary carbon atom provided that when said neopentyl polyhydric alcohol is trimethylolethane and each hydroxyl group thereof, other than that used to form the ester linkage with said dibasic carboxylic acid is substituted by a saturated aliphatic carboxylic acid radical the latter shall contain at least 5 carbon atoms (see Group IV(b)). By the term "neopentyl polyhydric alcohol" there is meant an alcohol which contains two or more hydroxyl groups and at least one and possibly a plurality, of neopentyl nuclei, each neopentyl nucleus comprising four methylene groups linked to a single carbon atom. Specified esters include the tetracaproates of trimethylol propane sebacate and adipate, the hexacaproates of pentaerythritol sebacate and adipate and the product obtained by esterifying one mole of adipic acid with two moles of the trimethyl ether of pentaerythritol.ALSO:The invention comprises esters represented by the general formula R2-OOC-R-COO-R2 wherein the group OOC-R-COO is derived from a dibasic carboxylic acid in which R is a hydrocarbon radical and wherein R1 and R2 which may be the same or different, are radicals each derived from a neopentyl polyhydric alcohol, the or each hydroxyl group of the neopentyl polyhydric alcohol, other than that used to form the ester linkage with said dibasic carboxylic acid, being substituted by an alkoxy radical containing from 1 to 12 carbon atoms or by a saturated aliphatic carboxylic acid radical containing from 4 to 18 carbon atoms or by a mononuclear aromatic carboxylic acid radical not substituted with an open chain aliphatic group containing a quaternary carbon atom provided that when said neopentyl polyhydric alcohol is trimethylolethane and each hydroxyl group thereof, other than that used to form the ester linkage with said dibasic carboxylic acid, is substituted by a saturated aliphatic carboxylic acid radical the latter shall contain at least 5 carbon atoms.  The term "neopentyl polyhydric alcohol" is defined as an alcohol which contains two or more hydroxyl groups and at least one, and possibly a plurality of neopentyl nuclei, each comprising four methylene groups all joined to a single carbon atom.  Neopentyl alcohols specified include neopentyl glycol, pentaerythritol, trimethylol-ethane, -propane and -butane, di-trimethylol-propane, dipentaerythritol and tripentaerythritol.  Dibasic acids specified for use in the preparation of the esters of the invention include saturated aliphatic, optionally aryl substituted dicarboxylic acids in which the alkylene group contains from 1 to 34 carbon atoms and is a straight, branched or cyclized chain and aromatic dicarboxylic acids in which R is an arylene group which may be alkyl substituted e.g. phthalic, isophthalic and terephthalic acids, naphthalene 1,5-dicarboxylic and methylene bis-benzoic acid. Monobasic acids which may be employed in preparing the esters may be straight or branched chain, cyclo- or araliphatic acids e.g. butyric caproic, caprylic, 2-ethylhexoic, pelargonic, capric, lauric, myristic, palmitic, stearic and phenylacetic or aromatic e.g. benzoic, toluic and p-t-butyl benzoic acid.  Monohydric alcohols with which the polyol may be etherified include methanol, isopropanol, hexanol, octanol or lauryl alcohol.  The esters of the invention may be prepared by esterifying the neopentyl alcohol firstly with the decarboxylic acid and then the monocarboxylic acid or the neopentyl alcohol may be esterified or etherified so as to leave one free methylol group and the product reacted with the dicarboxylic acid to form the diester or all three compounds may be reacted together.  The examples relate to the preparation of the hexacaproate of pentaerythritol adipate and sebacate and the tetracaproate of trimethylol propane adipate and sebacate. The product obtained by esterifying one mole of adipic acid with two moles of the trimethyl ether of pentaerythritol is mentioned. The products of the invention are employed in lubricating compositions and as plasticizers for polyvinyl chloride resins.