GB687347A - Improved lubricant blend - Google Patents

Abstract

Ester blends are prepared by reacting together in one or more stages and in the presence of an esterification catalyst if necessary, an aliphatic dicarboxylic acid or acids or esterifying equivalent, an aliphatic glycol or glycols, polyglycol or polyglycols or esterifying equivalent and an aliphatic alcohol or alcohols or esterifying equivalent in appropriate proportions adapted to yield after the final esterifying stage a mixture of a complex ester of general formula R1-OOC-R2-COO-R3-OOC-R4-COOR5, and the alcohol diester or diesters of the dicarboxylic acid or acids, R1 and R5 representing the alcohol (including ether alcohol) residues, R2 and R4 representing the hydrocarbon radicals of the acid or acids, and R3 representing the hydrocarbon or oxahydrocarbon radical of the glycol or glycols, all the radicals R1 to R5 being saturated and the total number of carbon atoms in the complex ester being from 20 to 100, preferably from 30 to 60. The preferred starting materials are the acids, glycols and alcohols used in presence of an esterification catalyst, but there may also be used alkali metal salts of the acids and halogen derivatives of the alcohol and glycol or the acid chlorides and alkali metal derivatives of the alcohol and glycol. The components may be reacted in several ways; thus all three may be refluxed together; the glycol may be reacted with the acid in a first stage to form a mixture of glycol half-ester and free acid, which mixture is then esterified with the alcohol; the alcohol may be reacted with the acid in a first stage to form a mixture of diester and alcohol half-ester, which mixture is then esterified with the glycol, and in these methods the preferred mol, ratio of the acid, alcohol and glycol starting materials are 2+n : 2+2n : 1 where n : 1 is the desired molar ratio of diester to complex ester in the blend; or the glycol, glycols, polyglycol or polyglycols may be reacted in the presence of an esterification catalyst with more than 2 molar proportions of an alkyl di-ester of a dicarboxylic acid whereby the blend of complex ester and diester is obtained in which connection, Specification 683,803 is referred to. Preferably, the blend contains a minor proportion of the diester. The processes may be artificially broken down to any number of desired stages; for example, half of the glycol may be esterified with all the acid, half the alcohol added in a second stage, the remainder of the glycol in a third and the remainder of the alcohol in a fourth stage. Suitable starting materials are C1 to C12 alkanols or mixtures thereof, e.g. iso-octanol, oxo-nonanol or other oxo-fractions, C6 to C20 acids or mixtures thereof, e.g. polymethylene succinic acids such as adipic or sebacic acid, C4 to C24 polyglycols such as tri- or tetra-ethylene glycol. Ester blends are described obtained by the one stage method or glycol half-ester method, water of esterification being removed by means of toluene as an entrainer, from (1) 2 mols. each of 2-ethyl hexanol and oxo-nonanol, 3 mols sebacic acid and one mol. polyglycol 200; (2) oxo-nonanol, sebacic acid and polyglycol 200, yielding blends containing 64 and 73 per cent complex ester; (3) nonanol, 2-ethyl-hexanol, sebacic acid and polyglycol 200, the resulting blend containing 79 per cent complex ester; (4) nonanol, capryl alcohol, sebacic acid and polyglycol 200, the resulting blend containing 81 per cent complex esters; the blends are compared with similar blends prepared by mixing the complex ester with the diester. Specifications 666,697, 683,803, and 687,346, [Group III], are referred to.ALSO:Lubricant ester blends for use, e.g. in aviation turbines, are prepared by reacting together in one or more stages in the presence of an esterification catalyst if necessary, an aliphatic dicarboxylic acid or acids or esterifying equivalent, an aliphatic glycol or glycols, polyglycol or polyglycols or esterifying equivalent and an aliphatic alcohol or alcohols or esterifying equivalent in appropriate proportions adapted to yield after the final esterifying stage a mixture of complex ester, of the general formula R1-OOOC-R2-COO-R3-OOC-R4-COO R5, and the alcohol diester or diesters of the dicarboxylic acid or acids, R1 and R5 being the alcohol (including ether alcohol) residues, R2 and R4 being the hydrocarbon radicals of the acid or acids, and R3 being the hydrocarbon or oxahydrocarbon radical of the glycol or glycols, all the radicals R1 to R5 being saturated and the total number of carbon atoms in the complex ester being from 20 to 100, preferably from 30 to 60. Several methods of effecting the preparation of the blends are described, (see Group IV(b)). The reactants are preferably used in the mol ratio of acid: alcohol:glycol of 2+n:2+n:1 where n:1 is the desired molar ratio of diester to complex ester in the blend; the diester preferably constitutes a minor proportion of the blend. Suitable starting materials are C1 to C12 alkanols or mixtures thereof, e.g. 2-ethyl hexanol, iso-octanol and oxo-nonanol or other oxo-fractions, C6 to C20 acids or mixtures thereof, e.g. polymethylene succinic acids such as adipic or sebacic, and C4 to C24 polyglycols, e.g. tri-and tetra-ethylene glycols. Blends are described obtained from (1) 2-ethyl-hexanol, oxo-nonanol, polyglycol 200 and sebacic acid, the blend containing 64 per cent complex ester; (2) oxo-nonanol, sebacic acid and polyglycol 200, blends being formed containing 64 and 73 per cent complex ester; (3) nonanol, 2-ethyl-hexanol, sebacic acid and polyglycol 200, the complex ester content being 79 per cent; (4) nonanol, capryl alcohol, sebacic acid and polyglycol 200, the complex ester content being 81 per cent. These blends are compared with those obtained by mixing the complex ester with the diester. Specifications 666,697, 683,803 and 687,346 are referred to.