Patent GB-657750-A (GB)
Title: Lubricating compositions
Filed: 1947-08-27
Abstract: A lubricating composition comprises an ester prepared by esterifying with a substituted or unsubstituted, saturated or unsaturated, aliphatic monocarboxylic acid one or both end groups of a liquid long-chain polyether which may be an oxygen ether or a mixed oxygen and sulphur ether and which itself has lubricating properties and has been prepared by polymerizing one or more alkylene oxides (other than unsubstituted ethylene oxide) alkylene (other than unsubstituted ethylene glycol) dihydroxy-thioethers and dihydroxy - polysulphides, together with an extreme pressure additive, an oxidation inhibitor, a gelling agent, a corrosion inhibitor or a bodying agent.  Additives to the esters specified are: substituted phenols, aromatic amines, or minor amounts of organic acids to give corrosion resistance; Na, K, Li, Ba or Ca soaps as gelling agents; polymeric methacrylates as bodying agents; and sulphur, phosphorus and chlorine compounds as extreme pressure additives.  Esterification of the long-chain polyether.-Acids specified: (1) Saturated-formic, acetic, propionic, butyric, valeric, caproic, enanthylic, caprylic, pelargonic, capric, undecylenic, lauric, tridecoic, myristic, pentadecanoic, palmitic, margaric, stearic, carnaubic, cerotic, and psyllic acids.  (2) Mono-olefinic-acrylic, methacrylic, dimethacrylic, crotonic, isocrotonic, vinylacetic; pentenic acids-tiglic, angelic and senecioic; hexenic, teracrylic, hypogeic, oleic, elaidic, erucic and behenic acids.  (3) Polyolefinic and acetylinic acids-sorbic, linoleic, linolenic; propiolic, 2-butynoic, 2-pentynoic, amyl propiolic, palmitolic, and stearolic acids.  (4) Mixtures of acids found in natural products, e.g. the acids from linseed, rapeseed, cottonseed, tall, soya bean, corn, rice, sesame, and mustard seed oils.  Oleic, linoleic, and linolenic are the preferred acids. Catalysts for the esterification comprise zinc chloride, hydrogen chloride, sulphuric acid, p-toluene sulphonic acid, phosphoric acids and metal oxides, e.g. titanium oxide.  The esterification may be carried out in presence of a diluent, e.g. hexanes, heptanes, octanes, nonanes, decanes, and dodecanes.  The esterification product is purified by treatment to remove catalyst, acids, water and solvents.  Preparation of the polyethers.-In order to have lubricating properties these must have a chain of at least 10 carbon atoms. They may be prepared from (1) alkylene oxides, epihalohydrins, glycides; (2) glycols derived from ethylene oxide or trimethylene glycol; the polymethylene glycols may have non-hydrocarbon radicals as substituents, e.g. hydroxyl, carboxyl, carbonyl groups or S, Se, Te, P, or N atoms; (3) hydroxy thioethers and polysulphides; (4) copolymers of members of the same or different classes aforesaid. Long lists of members of the above classes are given in the Specification.  The thioethers are of the general formula HO-R(S)pR-OH, where the R's are organic radicals and p is an integer from 1-6.  They include primary dihydroxy thioethers of the general formula HO-R-CH2S-CH2-R-OH which may be prepared by "abnormal" condensation of unsaturated alcohols with hydrogen sulphide, e.g. bis (gamma-hydroxypropyl) sulphide is prepared by condensation of allyl alcohol and H2S in a quartz tube irradiated by a 25 degree watt mercury vapour lamp. Gamma-mercapto alcohol is a by-product of the above reaction and may be isolated in the fraction distilling off at 132-134 DEG  C. When reacted with iodine and potassium hydroxide bis-(gamma-hydroxypropyl) disulphide was obtained.  The following examples illustrate the preparation of polyethers and their esterification: (1) the 2-ethylhexoate ester of polytrimethylene glycol was prepared by heating 700 parts trimethylene glycol and 28 parts p-toluene sulphonic acid in boiling decalin for 72 hours; 450 parts ethyl hexoic acid in 900 parts benzene were then added and the mixture refluxed until water separation ceased.  A red oil was obtained which was purified by treatment with activated carbon, washing with NaOH and distillation.  (3) Trimethylene glycol was polymerized as above and then esterified by refluxing with acetic anhydride in presence of p-toluene sulphonic acid; (4) polymerized bis(gamma-hydroxypropyl) sulphide and polymerized trimethylene glycol were acetylated as in (3); (5) glycidyl isopropyl ether was polymerized in presence of SnCl2, the polymer was acetylated as in (3).  The Specification as open to inspection under Sect. 91 referred to the esterification of thio ethers having hydroxyl substituents on both organic radicals attached to the sulphur atoms.  This subject-matter does not appear in the Specification as accepted.ALSO:Esters having lubricating properties are prepared by esterifying with a substituted or unsubstituted, saturated or unsaturated, aliphatic monocarboxylic acid, one or both end groups of a liquid long-chain polyether which may be an oxygen ether or a mixed oxygen and sulphur ether and which itself has lubricating properties and has been prepared by polymerizing one or more alkylene oxides (other than unsubstituted ethylene oxide), alkylene glycols (other than unsubstituted ethylene glycol), dihydroxy - thioethers and dihydroxy - polysulphides.  Acids specified for the esterification are: (1) saturated-formic, acetic, propionic, butyric, valeric, caproic, enanthylic, caprilyic, pelargonic, capric, undecylenic, lauric, tridecoic, myristic, pentadecanoic, palmitic, margaric, stearic, carnaubic, carotic, and psyllic acids; (2) mono-olefinic-acrylic, methacrylic, dimethyacrylic, crotonic, isocrotonic, vinylacetic; pentenic acids such as tiglic, angelic and senecioic; hexenic, teracrylic, hypogeic, oleic, elaidic, erucic and behenic acids; (3) polyolefinic and acetylinic acids-sorbic, linoleic, linolenic; propiolic, 2-butynoic, 2-pentynoic, amyl propiolic, palmitolic, and stearolic acids; (4) mixtures of acids found in natural products, e.g. the acids from linseed, rapeseed, cottonseed, tall, soyabean, corn, rice, sesame, and mustard seed oils.  Reference is made to hydroxy, ketonic and amino acids and sulphur-treated unsaturated acids, e.g. oleic acid.  Oleic, linoleic, and linolenic are the preferred acids.  Catalysts for the esterification comprise zinc chloride, hydrogen chloride, sulphuric acid, p-toluene sulphonic acid, phosphoric acids and metal oxides, e.g. titanium oxide.  The esterification may be carried out in presence of a diluent, e.g. hexanes, heptanes, octanes, nonanes, decanes, and dodecanes.  The esterification product is purified by treatment to remove catalyst, acids, water and solvents.  The polyether starting materials-in order to have lubricating properties-must have a chain of at least 10 carbon atoms.  They may be prepared from (1) alkylene oxides, epihalohydrins, glycides; (2) glycols, e.g. those derived from ethylene or trimethylene glycol; the latter glycols have the general formul  <FORM:0657750/IV (b)/1> or <FORM:0657750/IV (b)/2> where s is an integer and the free valencies are satisfied by hydrogen or organic radicals and such radicals include, for the trimethylene glycols, hydroxyl, carboxyl and carbonyl groups and also S, Se, Te, P or N atoms; higher polymethylene glycols are also mentioned; (3) hydroxy thioethers and polysulphides; (4) copolymers of members of the same of different classes aforesaid. Long lists of members of the above classes are given in the Specification.  The thioethers are of the general formula HO-R(S)pR-OH, where the R's are organic radicals, preferably saturated aliphatic hydrocarbon radicals which, however, may contain carboxy, carbonyl or hydroxy groups, and p is an integer preferably from 1-6.  They include primary dihydroxy thioethers of the general formula HO-R-CH2S-CH2-R-OH, which may be prepared by "abnormal" condensation of unsaturated alcohols with hydrogen sulphide, e.g. bis-(gamma-hydroxypropyl) sulphide is prepared by condensation of allyl alcohol and H2S in a quartz tube irradiated by a 250-watt mercury vapour lamp; other suitable alcohols are mentioned. Gamma-mercapto propyl alcohol is a by-product of the above reaction and may be isolated in the fraction distilling off at 132-134 DEG  C. When reacted with iodine and potassium hydroxide bis - (gamma - hydroxypropyl) disulphide was obtained.  The polysulphides have the same general formula but p is preferably 2 to 6.  The following examples illustrate the preparation of polyethers and their esterification.  Lubricating compositions comprising the ester products of the invention are described (see Group III).  (1) 2-ethyl-hexoate ester of polytrimethylene glycol.-700 parts trimethylene glycol and 28 parts p-toluene sulphonic acid were heated in boiling decalin for 72 hours; 450 parts ethyl hexoic acid in 900 parts benzene were then added and the mixture refluxed until water separation ceased. A red oil was obtained which was purified by treatment with activated carbon, washing with NaOH, and distillation. (3) Trimethylene glycol was polymerized as above and then esterified by refluxing with acetic anhydride in presence of p-toluene sulphonic acid.  (4) Polymerized bis-(gamma-hydroxypropyl) sulphide and polymerized trimethylene glycol were acetylated as in (3).  (5) Glycidyl isopropyl ether was polymerized in presence of SnCl2, the polymer was acetylated as in (3).  The Specification as open to inspection under Sect. 91 relates to the preparation of esters of compounds having the general formula H[(O-R3)m-(StR4)p-1]n-OH, where R3 and R4 are organic radicals and m, n, p and t are integers including one, by esterification of polymers and copolymers of alkylene oxides, alkylene glycols, monomers and polymers of hydroxy thioethers and of hydroxy polysulphides by means of the appropriate carboxylic acids or the corresponding salts, anhydrides, cyanides and chlorides.  The acids mentioned include, in addition to the above-specified acids, aliphatic