Patent GB-798653-A (GB)
Title: New carboxylic acid esters and lubricating compositions thereof
IPC: C07C69/34
Filed: 1955-12-22
Abstract: The invention comprises simple and complex esters of mixtures of isomeric C10 aliphatic dicarboxylic acids comprising a major proportion by weight of a -ethyl suberic acid, the ester mixtures having the sum formula A-X-B, wherein X represents the acyl radicals of the isomeric mixture of C10 acids, A represents either (1) aliphatic monohydric alcohol radical -[-X-glycol radical-]-y; or (2) acyl radical of an aliphatic monocarboxylic acid-glycol radical -[-X-glycol radical-]-z and B represents either (1) aliphatic monohydric alcohol radical; or (2) glycol radical-acyl radical of an aliphatic monocarboxylic acid, y and z being numbers from 0 to 6. Three types of complex esters are described.  The first have the structure aliphatic mono carboxylic acid - glycol - (dibasic acid-glycol)n-aliphatic monocarboxylic acid, n being an integer from 1 to 7.  These may be prepared by admixing the calculated amounts of the various compounds in the proportions shown in the structural formula and subjecting the mixture to esterification, water of esterification being removed by a water-entrainer; alternatively, esters of this type may be prepared by reacting the monobasic acid with the glycol under esterifying conditions in proportions yielding a half-ester, two mols. of which are then esterified with one mol. of the C10 acid mixture.  The second type have the structure: aliphatic monohydric alcohol-dibasic acid-(glycol-dibasic acid)n-aliphatic monohydric alcohol, n being an integer of 1 to 6, and these may be prepared by esterifying a mixture of the components in the molecular proportions calculated from the structural formula, with removal of the water formed by means of a water-entrainer.  The third type have the structure: aliphatic monohydric alcohol-(dibasic acid-glycol)n-monobasic aliphatic carboxylic acid, n being an integer from 1 to 7, and these may be prepared by esterifying the calculated amounts of glycol and dibasic acid mixture as shown in the structural formula, water formed being removed with a water-entrainer and reacting the resulting half-ester with 1 mol. each of the aliphatic alcohol and monobasic acid.  The ester mixtures may also be prepared by esterifying the individual acids of the C10 isomeric mixture and then blending together the individual esters. The preferred isomeric acid mixtures comprise about 60-90 per cent of the ethyl-suberic acid, about 5-25 per cent of a  : a 1-diethyl adipic acid and about 5-15 per cent of sebacic acid and are obtainable by dimerizing butadiene and then converting the dimer mixture to the isomeric C10 dibasic acids by reaction with HCN, or NaCN and HCl, followed by hydrolysis or by oxonation followed by oxidation.  The monohydric alcohols may contain up to 20 carbon atoms and are preferably primary alcohols.  Numerous examples are given including methanol, 2-ethyl butanol, oleyl alcohol, various alkyl ethers of mono and polyethylene and propylene glycols, several alkyl thio ethers of alkanols and alkoxy alkanols, and oxo alcohols.  As glycols there may be used ethylene glycol and its homologues, polyethylene and polypropylene glycols and glycols containing this linkage in the alkylene groups and many examples are given.  The monocarboxylic acids are preferably saturated and examples include acetic, valeric, pelargonic, stearic, oleic, b -methoxypropionic, b -tertiary-dodecyl mercapto propionic acids.  The ester mixtures preferably have a M.W. of 300-1200 and a viscosity at 210 DEG  F. not greater than 15 centistokes.  The esters may be used in lubricating compositions (see Group III).  In examples: (1) single diesters are prepared from a mixture of C10 dibasic acids having a composition within the preferred values mentioned above, by heating the acids with a 10 per cent excess of C7 oxo alcohols derived from a propylene-butylene polymer in the presence of heptane as a water entrainer and NaHSO4 as catalyst and the resulting ester mixture is purified by washing with dilute Na2CO3 solution and then stripping under reduced pressure at about 200 DEG C.; the lubricating properties of the product are compared with those of a simple diester prepared in like manner from sebacic acid; (2) a complex ester-mixture is prepared by heating a mixture of 2 mols. of the C10 dibasic acid mixture of (1), 1 mol. of thiodiglycol and 2 mols. plus 20 per cent excess of C8 oxo alcohols obtained from a propylene-butylene polymer, the esterification being effected as in (1) and the lubricating properties of the product are compared with a complex ester prepared similarly from the same glycol and 2-ethyl hexanol and sebacic acid; (3) the method of (2) is repeated using tetraethylene glycol as the glycol reagent; (4) a simple diester mixture is prepared from the same C10 isomeric dibasic acids and C7 oxo alcohols derived from C6 olefines obtained in gas oil cracking, esterification being carried out as in (1) in the additional presence of phenothiazine as oxidation inhibitor; a comparative experiment carried out under the same conditions uses sebacic acid alone.ALSO:Lubricating compositions comprise estermixtures having the sum formula A-X-B wherein X represents the acyl radicals of a mixture of isomeric aliphatic C10 dicarboxylic acids comprising a major proportion by weight of a -ethyl suberic acid. A represents either (1) aliphatic monohydric alcohol radical -[-X-glycol radical-]-g or (2) acyl radical of an aliphatic monocarboxylic acid-glycol radical -[-X-glycol radical-]-z and B represents either (1) -aliphatic monohydric alcohol radical; or (2) -glycol radical-acyl radical of an aliphatic monocarboxylic acid, y and z being numbers from 0 to 6. The esters may be simple esters or complex esters having the structures: aliphatic monocarboxylic acid-glycol-(dibasic acid-glycol)n-aliphatic monocarboxylic acid, n being an integer from 1 to 7; aliphatic monohydric alcohol-dibasic acid-(glycol-dibasic acid)n-aliphatic monohydric alcohol, n being an integer from 1 to 6; aliphatic monohydric alcohol-(dibasic acid-glycol)n-monobasic alphatic carboxylic acid, n being an integer from 1 to 7.  The esters may be used with other lubricant base stocks such as mineral lubricating oils, other synthetic ester type lubricants, including mono- and di-basic acid esters, glycol esters and complex esters, phosphoric acid esters, halocarbon oils, alkyl salicates, silicones, siloxanes, sulphite esters, carbonate esters, mercaptals, formals and polyglycols, many examples being given. Lubricant additives of the conventional types, including thickeners to form greases, may also be present.  The ester-mixtures preferably have a M.W. of 300-1200 and a viscosity at 210 DEG  F. not greater than 15 centistokes.  Their preparation is described (see Group IV (b)) and numerous starting materials are specified.  The C10 isomeric dibasic acid mixture preferably contains 60-90 per cent of a -ethyl suberic acid, 5-25 per cent of a  : a 1-diethyl adipic acid and 5-15 per cent sebacic acid. Other specified reagents include methyl, 2-ethyl butyl, cetyl and oleyl alcohols, various mono-ethers and thio-ethers of glycols, n-butyl mercapto ethoxy ethanol, n-dodecyl mercapto propoxy propanol and oxoalcohols; ethylene, propylene and pentamethylene glycols, polyglycols and thioglycols; acetic, caprylic, pelargonic, oleic, b -methoxy propionic and b -tert.-dodecyl mercapto propionic acids.  An examples describes a lubricating composition comprising 90 per cent by volume of di-2-ethyl hexyl sebacate and 10 per cent of a complex ester obtained by esterification of 2 mols. of the dibasic acid mixture described above, 1 mol. of thiodiglycol and 2 mols. + 20 per cent excess of C8 oxo alcohols.  The lubricating properties are described of simple diester mixtures obtained from the same C10 acid mixture and C7 oxo alcohols, and a complex-ester mixture obtained as in the example, but using tetraethylene glycol as the glycol reagent.ALSO:The invention comprises simple and complex esters of mixtures of isomeric C10 aliphatic dicarboxylic acids comprising a major proportion by weight of a -ethyl suberic acid, the estermixtures having the sum formula A-X-B, wherein X represents the acyl radicals of the isomeric C10 acids, A represents either (1) aliphatic monohydric alcohol radical -[-X-glycol radical-]-y, or (2) acyl radical of an aliphatic monocarboxylic acid-glycol radical -[-X-glycol radical-]-z and B represents either (1) aliphatic monohydric alcohol radical, or (2) glycol radical-acyl radical of an aliphatic monocarboxylic acid, y and z being numbers from 0. to 6 Three types of complex estermixtures are described.  The first have the structure aliphatic monocarboxylic acid-glycol(dibasic acid-glycol-)-n aliphatic monocarboxylic acid, n being an integer from 1 to 7.  These are prepared by subjecting a mixture of the components in the molar proportions shown in the structural formula to esterification, water of reaction being removed with a waterentrainer; alternatively, esters of this type may be prepared by esterifying the mono-basic acid with the glycol and esterifying 2 mols. of the resulting half-ester with 1 mol. of the dibasic acid mixture.  The second type have the structure: aliphatic monohydric alcoholdibasic acid - (glycol - dibasic acid)n - aliphatic monohydric alcohol, n being an integer from 1 to 6 and these may be prepared by esterifying a mixture of the components in proportions calculated from the formula with removal of water of reaction with a water entrainer.  The third type have the structure: aliphatic monohydric alcohol-(dibasic acid-glycol)n-monobasic aliphatic carboxylic acid, n being an integer from 1 to 7 and these may be prepared by esterifying the glycol and dibasic acid mixture in amounts calculated from the given formula to form a half-ester, water of reaction being removed with a water-entrainer, and then reacting the half-ester with one mol. each of t