Patent GB-442289-A (GB)
Title: Improvements relating to lubricants
Filed: 1934-07-30
Abstract: As additions to mineral lubricating oils, use is made of (a) products obtained from hydroxyfatty acids containing at least ten carbon atoms (or their esters esterified at the carboxylic group) by esterifying the hydroxy group or groups with a carboxylic acid or its anhydride, and stabilizing the products as described below, or (b) products obtained from the hydroxyfatty acids defined above (or their esters esterified at the carboxylic group) by esterifying the hydroxy group or groups with a carboxylic acid halide, and optionally stabilizing the products as described below.  The stabilization treatment may consist in distilling off not less than about ten per cent by weight of the products, any free acidity which develops in the distillation residue being preferably eliminated by neutralization or esterification.  Other stabilizing treatments, for application to unsaturated products, are (a) hydrogenation, which may be continued or not until a saturated product is obtained, or (b) halogenation or (c) hydroxylation, for example with hydrogen peroxide in presence of acetic acid, followed by esterification.  Specified hydroxyfatty acids (or esters esterified at the carboxylic group) are castor oil, ricinoleic acid, quince oil, mono- and poly-hydroxystearic acids, and glycerides of the hydroxyacids obtained by oxidizing paraffin wax or like hydrocarbons; esters of the hydroxy acids with monohydric alcohols, particularly those containing one to five carbon atoms, or with glycols, polyglycols, polyglycerols, chlorhydrins and aminohydroxy compounds may also be used, as well as polymerization products of the acids or esters, such as polyricinoleic acids, estolides, lactones and lactides.  Specified carboxylic acids, which, as such or an anhydrides or halides, may be used for esterifying the hydroxy group or groups of the hydroxycarboxylic acids or esters are formic, acetic, propionic, butyric, valeric, oleic, stearic, sebacic, benzoic or phthalic acid, acids derived from oils, fats and waxes, e.g. from castor oil, corn oil or lard oil, and acids obtained by oxidizing paraffin wax or oils.  Mixtures of acids (or anhydrides or halides) may be used in the esterification, or the latter may be conducted in stages with the use of different acids (or anhydrides or halides) in the different stages; thus, castor oil may be partly esterified with a higher aliphatic acid or phthalic acid, and esterification then completed with a lower aliphatic acid such as acetic acid.  An esterification catalyst, e.g. sulphuric or hydrochloric acid or boron fluoride, may be present.  When the hydroxy groups of free hydroxyfatty acids are esterified, the carboxylic group may be afterwards esterified.  Examples are given illustrating the use of: (1) castor oil esterified with acetyl chloride, (2) castor oil esterified with acetyl chloride and then hydrogenated, (3) castor oil partly esterified with phthalyl chloride, (4) castor oil partly esterified with phthalyl chloride and further esterified with acetyl chloride, (5) castor oil esterified with acetic anhydride and then stabilized by distillation as described above; for comparative purposes, the Specification describes also the use of castor oil which has been esterified with acetic anhydride but not stabilized. Specification 15497/09, [Class 2 (iii)], is referred to.  The Specification as open to inspection under Sect. 91 indicates that a stabilization treatment is optional, irrespective of whether a carboxylic acid or its anhydride or halide is used for the esterification.  It refers to alkylation, arylation, and heating (as distinct from distillation) as stabilization treatments which may be applied, and states that stabilization may precede esterification or may be effected simultaneously therewith. Inorganic acids, such as phosphoric or boric acid, are stated to be suitable as esterifying agents.  Examples are given in which: (1) castor oil is esterified with sebacic acid; (2) castor oil is esterified with corn oil acids; (3) castor oil is acetylated with a mixture of acetic and sulphuric acids, and the product is stabilized by heating it to 300--340 DEG  C.; (4) castor oil is hydrogenated and then acetylated with acetic and sulphuric acids.  This subject-matter does not appear in the Specification as accepted.ALSO:As additions to mineral lubricating-oils, use is made of (a) products obtained from hydroxyfatty acids containing at least ten carbon atoms (or their esters esterified at the carboxylic group) by esterifying the hydroxy group or groups with a carboxylic acid or its anhydride, and stabilizing the products as described below, or (b) products obtained from the hydroxyfatty acids defined above (or their esters esterified at the carboxylic group) by esterifying the hydroxy group or groups with a carboxylic acid halide, and optionally stabilizing the products as described below.  The stabilization treatment may consist in distilling off not less than about 10 per cent by weight of the products, any free acidity which develops in the distillation residue being preferably eliminated by neutralization or esterification. Other p  stabilizing treatments, for application to unsaturated products, are (a) hydrogenation, which may be effected at atmospheric or raised temperature and pressure in the presence of known catalysts, e.g. nickel, copper or palladium, and may be continued or not until a saturated product is obtained, or (b) halogenation or (c) hydroxylation, for example, with hydrogen peroxide in presence of acetic acid, followed by esterification.  Specified hydroxyfatty acids (or esters esterified at the carboxylic group) are castor oil, ricinoleic acid, quince oil, mono- and poly-hydroxystearic acids, and glycerides of the hydroxyacids obtained by oxidizing paraffin wax or like hydrocarbons; esters of the hydroxy acids with monohydric alcohols, particularly those containing one to five carbon atoms, or with glycols, polyglycols, polyglycerols, chlorhydrins and aminohydroxy compounds may also be used, as well as polymerization products of the acids or esters, such as polyricinoleic acids, estolides, lactones and lactides.  Specified carboxylic acids which, as such or as anhydrides or halides, may be used for esterifying the hydroxy group or groups of the hydroxycarboxylic acids or esters are formic, acetic, propionic, butyric, valeric, oleic, stearic, sebacic, benzoic or phthalic acid, acids derived from oils, fats and waxes, e.g. from castor oil, corn oil or lard oil, and acids obtained by oxidizing paraffin wax or oils.  Mixtures of acids (or anhydrides or halides) may be used in the esterification, or the latter may be conducted in stages with the use of different acids (or anhydrides or halides) in the different stages; thus, castor oil may be partly esterified with a higher aliphatic acid or phthalic acid, and esterification then completed with a lower aliphatic acid such as acetic acid.  An esterification catalyst, e.g. sulphuric or hydrochloric acid or boron fluoride, may be present.  When the hydroxy groups of free hydroxyfatty acids are esterified, the carboxylic group may be afterwards esterified. The products may be blended with mineral lubricating oils in a proportion of 0,5--50 per cent or more, or they may be made into greases by blending with mineral lubricating oils and soaps, e.g. with 2--30 per cent of sodium, calcium or lead soaps of fatty or naphthenic acids.  An antioxidant, e.g. a naphthol, a naphthylamine, hydroquinone, a thionaphthol, an organic di-or poly-sulphide, a thioether, or an organometallic compound such as an aryl or alkyl compound of lead, tin, mercury or bismuth, is preferably added to the compositions. Examples are given illustrating the lubricant properties of mixtures of mineral lubricating oils with (1) castor oil esterified with acetyl chloride, (2) castor oil esterified with acetyl chloride and then hydrogenated, (3) castor oil partly esterified with phthalyl chloride, (4) castor oil partly esterified with phthalyl chloride and further esterified with acetyl chloride, (5) castor oil esterified with acetic anhydride and then stabilized by distillation as described above; for comparative purposes, the Specification states also certain properties of mixtures of mineral lubricating oils with castor oil which has been esterified with acetic anhydride but not stabilized.  Specification 15497/09, [Class 91], is referred to.  The Specification as open to inspection under Sect. 91 indicates that a stabilization treatment is optional, irrespective of whether a carboxylic acid or its anhydride or halide is used for the esterification.  It refers to alkylation, arylation, and heating (as distinct from distillation) as stabilization treatments which may be applied, and states that stabilization may precede esterification or may be effected simultaneously therewith.  Inorganic acids, such as phosphoric or boric acid, are stated to be suitable as esterifying agents.  The products are stated to be useful as lubricants, alone or in admixture with mineral oils and/or soaps.  Examples are given in which (1) castor oil is esterified with sebacic acid; (2) castor oil is esterified with corn oil acids to give a product soluble in mineral oils; (3) castor oil is acetylated with a mixture of acetic and sulphuric acids, and the product is stabilized by heating it to 300--340 DEG  C.; (4) castor oil is hydrogenated and then acetylated with acetic and sulphuric acids; (5) details are given of the oxidation rate of mixtures of mineral lubricating oil with acetylated castor oil (method of acetylation not specified).  This subject-matter does not appear in the Specification as accepted.