Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
  • C10M105/08—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing oxygen
  • C10M105/32—Esters
  • C10M105/38—Esters of polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
  • C07C69/02—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen
  • C07C69/22—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen having three or more carbon atoms in the acid moiety
  • C07C69/33—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen having three or more carbon atoms in the acid moiety esterified with hydroxy compounds having more than three hydroxy groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/281—Esters of (cyclo)aliphatic monocarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/282—Esters of (cyclo)aliphatic oolycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/283—Esters of polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/286—Esters of polymerised unsaturated acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
  • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/08—Resistance to extreme temperature
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/12—Gas-turbines
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/12—Gas-turbines
  • C10N2040/13—Aircraft turbines

Definitions

• This invention relates to synthetic lubricant compositions containing pentaerythritol mixed esters. More particularly, the invention relates to synthetic lubricant compositions which are especial-1y adapted for use with aircraft engines of the turbo-propeller and turbo-shaft types containing pentaerythritol mixed esters. It also relates to a method of lubricating such aircraft engines. This application is a containuation-in-part of co-pending application Ser. No. 287,219 filed June 12, 1963 and now abandoned.
• pentaerythritol esters generally perform satisfactorily as lubricants because they possess good thermal stability characteristics, they do not always meet the aforementioned viscosity requirement for jet engines at temperatures ranging from 40 F. to 210 F. At high temperatures, certain esters lose their cohesiveness indicated by an exceedingly low kinematic viscosity, and they tend to become thin. This tendency represents a loss of lubricity. At low temperatures, on the other hand, some esters tend to crystallize or form solids, or else they are too viscous to flow smoothly and freely. Esters having such characteristics could seriously impede the eflicient operation of the aircraft engine and even damage the moving parts of the engine.
• One object of this invention is to provide lubricant compositions which possess satisfactory kinematic viscosities at temperatures from about 40 F. to 210 F.
• Another object is to provide pentaerythritol esters which have initial kinematic viscosities below 10,000 centistokes at 40 F.
• a further object is to provide novel lubricant compositions which satisfy the lubricity requirements of jet engine specifications.
• novel lubricant compositions which are liquid and possess lubricity at temperatures between -40 F. and 210 F., containing as an essential ingredient an esterification product of pentaerythritol and a mixture of two to six monocarboxylic alkanoic acids having from 5 to 9 carbon atoms, in which mixture the average number of carbon atoms is in the range of 6.0 to 7.25 and the maximum number of carbon atoms contributed by the straight-chain 8- and 9- carbon acids is 60% and the maximum number contributed by branched chain acids is 45% of the average number of carbon atoms.
• the novel pentaerythritol mixed esters of this invention have satisfactory initial kinematic viscosities at 210 F. and below 13,000 centistokes at -40 F. if the mixed acid reactants, of from 5 to 9 car- 3,360,465 Patented Dec. 26, 1967 bon atoms, are present in such molar quantities that the total number of carbon atoms contributed by acids in the mixture having straight-chain 8 and 9 carbon atoms is below 60% of the average number of carbon atoms and the total contributed by all branched acids is below 45%. In other words, upon complete esterification, the maximum number of carbon atoms contributed by the straight-chain 8- and 9-carbon acids is about 4.25 and that contributed by the branched acids is about 3.25.
• initial kinematic viscosities of less than 10,000 centistokes at -40 F. are obtained, using a technical or commercial grade of pentaerythritol, wherein the average number of carbon atoms of the acid mixture is in the range of 6.2 to 6.7, with percent carbon atom contributions of below 52% and 40% for the straight-chain 8- and 9-carbon acids and branched chain acids, respectively.
• Lubricant compositions containing these preferred esters have sufliciently low initial kinematic viscosities that they may be operative at temperatures even lower than 40 F.
• An acid mixture to be reacted with pentaerythritol contains mole percent of caprylic acid (denoted C 15 mole percent of pelargonic acid (C 45 mole percent of -a commercial isopentanoic acid (C containing 29.25 mole percent of normal valeric and 15.75 mole percent).
• caprylic acid denoted C 15 mole percent of pelargonic acid (C 45 mole percent of -a commercial isopentanoic acid (C containing 29.25 mole percent of normal valeric and 15.75 mole percent
• the initial kinematic viscosity at 40 F. of an ester made from a technical grade of pentaerythritol and this acid mixture is 8425 centistokes; at 210 F., the initial kinematic viscosity is 5.10 centistokes.
• pentaerythritol is initially mixed with at least four moles per mole of pentaerythritol of a mixture of two to six monocarboxylic alkanoic acids of from 5 to 9 carbon atoms, selected according to desired molar proportions. A 5% to'1-0% excess of the acid mixture over the stoichiometric requirement is preferred.
• the reaction is carried out by heating the reaction mixture in a liquid phase under reflux conditions for a period of from 6 to 10 hours.
• the reaction temperature may be from about 275 to 450 F.
• the methylol groups of the pentaerythritol are esterified by the acids, causing four moles of water to be split off per mole of pentaerythritol.
• the esterification reaction is complete when the four moles of water are removed.
• the reaction may be carried out in the presence of an azeotroping agent, such as toluene, benzene or other suitable agent which in inert to the reactants.
• the acids within the to 9 carbon atom range which may be used in my invention are the presently available commercial acids including the normal acids, valeric, caproic, caprylic and pelargonic, and the branched chain acids isopentanoic and 2-methyl pentanoic.
• the esters are made from either all straight-chain acids or mixed straight and branched chain acids. While I prefer to use straightchain caprylic and pelargonic acids, the lower acids, however, may be either all straight-chain acids or all branched or m-ixed.
• the isopentanoic acid used herein is a typical commercial blend containing 60% to 65% by weight of n-valeric and 40% to 35% by weight of the Z-methyl and 3-methyl butyric acid isomers.
• the methyl butyric acid isomers are treated as identical acids in computing the percent of branched acid contribution, while the entire mixture, including normal valeric, has the same number of carbon atoms with regard to computing the average number of carbon atoms.
• Two to six different acids are used to prepare my lubricants and hence the reaction product may be either a mixed ester or a mixture of mixed esters.
• I herein refer to the reaction product as simply a mixed ester or an ester-ification product.
• the pentaerythritol which I use in describing my invention is the technical or commercial grade of pentaerythritol, such as Pente (a product of the Heyden Chemical Corporation), which usually contains about 88 to 90% monopent-aerythritol, to 1 2% dipentaerythritol, and less than 0.5% tripentaerythritol.
• Pente a product of the Heyden Chemical Corporation
• monopent-aerythritol to 1 2% dipentaerythritol, and less than 0.5% tripentaerythritol.
• -I also use a higher grade of pentaerythritol such as.Monopentek (also produced by the Heyden Chemical Corporation); this product contains about 98.5% monopentaerythritol and 1.5% dipentaerythritol.
• the reaction vessel was closed and nitrogen gas was passed through at atmospheric pressure.
• the vessel was then heatedfrom about 300 to 450 F. for 7 to 9 hours under agitation until about 144 parts of water were condensed, indicating substantially complete esterification.
• a lubricant composition containing essentially the ester of Example I was subjected to a l'50-hour test run in a Pratt and Whitney JT-3D test engine following the procedure of Pratt and Whitney Type II Lubricating Oil Specification for Aircraft Turbine Engines. This specification calls for adding the sample lubricant to the engine and running the engine through a series of 5-hour and 10-hour cycles, operating at 20,000 pounds of thrust at a temperature in excess of 600 F. The lubricant is periodically tested for thermal and oxidative stability.
• the lubricant was found to comply with acceptable standards. It showed satisfactory thermal and oxidative stability, and the bearings and other metal parts in contact with the lubricant were clean and free of corrosion, wear or cracking.
• EXAMPLE H Using the same procedure and apparatus as in Example I, 272.3 parts (2 moles) of pentaerythritol (using technical grade pentaerythritol) were mixed with an acid mixture consisting of 584.2 parts (5.72 moles) of commercial isopentanoic acid (containing 65 of n-valeric acid and 35% by weight of Z-methyl and 3-methyl butyric acid) and 487.4 parts (3.08 moles) of pelargonic acid. This mixture thus consists of 22.75 mole percent of Z-methyl and 3-methyl butyric acids, 42.25 mole percent of normal valeric, and 35 mole percent of pelargonic.
• pentaerythritol using technical grade pentaerythritol
• an acid mixture consisting of 584.2 parts (5.72 moles) of commercial isopentanoic acid (containing 65 of n-valeric acid and 35% by weight of Z-methyl and 3-methyl butyric acid) and 487.4 parts
• the average carbon atom content is 6.4, the percent C contribution is 49.3 and the percent branched acid contribution is 17.8.
• the reactants were added to the reaction vessel and heated. When a total of 144 parts of water was collected in the condensate receiver, the heat was removed.
• the tables include the molar percentages of the acids and the carbon atoms contributed by each (C.A.), the average number of carbon atoms in the acid mixture (being the sum of the carbon atoms contributed), the carbon atom percentages for the C and C acids and for the branched acids, and the initial kinematic viscosities of the ester at 210 F. and -40 F.
• Example 9 the average carbon atom content of the esterifying acid mixture by itself is an inadequate means of predicting either the high or the low temperature viscosity.
• Example 9 the average number of carbon atoms is 6.7 and in Example 10 it is 6.5.
• Example 10 the low temperature viscosity for Example 10 is higher than that of Example 9.
• an ester was prepared from pentaerythritol and the following mixture of acids: caprylic, 35 mole percent; pelargonic, 15 mole percent; and n-valeric, mole percent. The average number of carbon atoms is 6.65, but the percent C and C contribution is 62.4. At 40 F., the ester crystallized.
• a second pentaerythritol ester was prepared from the following acid mixture: pelargonic 30 mole percent and Z-methyl pentanoic mole percent. The average number of carbon atoms is 6.9, but the percent branched acid contribution is 56.5.
• the initial kinematic viscosity of this ester was 14,530 centistokes.
• esters of this invention are compatible with the usual lubrication additives which may be added to enhance the properties of the esters. Minor amounts of such lubrication additives as antioxidants, stabilizers, corrosion inhibitors, detergents and the like may be added, depending upon the additional properties sought. These additives generally increase the kinematic viscosities of the esters, and therefore selection of the ester should be made with regard to such physical effect. My esters also have both excellent storage stability and chemical stability during use.
• 75 consisting essentially of an ester of pentaerythritol and a mixture ofalkanoic acids consisting essentially of about 25 mol percent caprylic acid, about mol percent methyl pentanoic acid, in the range of from about 15 to about pelargonic acid, and in the range of from about 40 to about 45 mol percent valeric acid, said mixture' of alkanoic acids having in the range of from about 6.5 to about 6.7 carbon atoms per acid molecule, said pelargonic and caprylic acids consisting of from about 51 /2 to about 57 mol percent of said alkanoic acids, said alkanoic acids consisting of not more than 15 mol per cent of branched acids, said composition being characterized by remaining liquid and also maintaining its lubricity at -40 F, and further characterized by an initial kinematic viscosity of not more than about 6800 centistokes at 40 F.
• a lubricant composition adapted for use at 40 F. consisting essentially of a pentaerythritol ester of a mixture of 1alkanoic acids consisting essentially in the range of from about to about mol percent pelargonic acid, in the range of from about 39, to about 45 /z mol percent n-valeric acid, and in the range of from about 22% to about 28 percent of a mixture of methyl butyric 8 acid isomers, said composition being characterized by remaining liquid and also maintaining its lubricity at F., and an initial kinematic viscosity of not more than 8425 centistokes at 40 F.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Emergency Medicine (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Lubricants (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (4)

• 0
  • BE BE649019D patent/BE649019A/xx unknown
• 1964
  • 1964-05-22 US US369600A patent/US3360465A/en not_active Expired - Lifetime
  • 1964-06-03 GB GB23078/64A patent/GB1049716A/en not_active Expired
  • 1964-06-11 NL NL6406651A patent/NL6406651A/xx unknown
  • 1964-06-12 DE DED44682A patent/DE1281422B/de active Pending

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