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
• • 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
  • C10M101/00—Lubricating compositions characterised by the base-material being a mineral or fatty oil
  • C10M101/04—Fatty oil fractions
• • 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
  • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
  • C10M107/20—Lubricating compositions characterised by the base-material being a macromolecular compound containing oxygen
  • C10M107/30—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
• • 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
• • 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
  • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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

Definitions

• This invention relates to esters of oleic acid estolides and their use as biodegradable base stocks and lubricants . Description of the Prior Art
• Synthetic esters such as polyol esters and adipates, low viscosity poly alpha olefins (PAO) , such as PAO 2, vegetable oils, especially Canola oil and oleates are used industrially as biodegradable basestocks to formulate lubricants.
• Lubricants usually contain 80-100% wt . basestock and 0-20% wt . additives to tailor their viscometric properties, low temperature behavior, oxidative stability, corrosion protection, demulsibility and water rejection, friction coefficients, lubricities, wear protection, air release, color and other properties. Biodegradability cannot be improved by using additives.
• estolides are a unique oligomeric fatty acid that contains secondary ester linkages on the alkyl backbone of the molecule .
• Estolides have typically been synthesized by the homopolymerization of castor oil fatty acids [Modak et al . , JAOCS 42:428 (1965); Neissner et al . , Fette Seifen Anstrichm 82:183
• Estolides derived from these sources are composed of esters at the 12 carbon of the fatty acids and have a residual hydroxyl group on the estolide backbone.
• the level of unsaturation in the produced estolides is not significantly lower than that in raw materials, i.e., hydroxy fatty acids.
• estolide compounds derived from oleic acids and characterized by superior properties for use as lubricant base stocks. These estolides may also be used as lubricants without the need for fortifying additives normally required to improve the lubricating properties of base stocks .
• estolide esters of this invention are generally characterized by Formula (I) :
• polyestolides is used herein to refer to the acid form of compounds having the structure of Formula I, wherein n is greater than 0.
• u ester , " estolide ester” and the like are generally used herein to refer to products produced by esterifying the residual fatty acid (attachment of the R group in Formula I) on the estolide or estolide mixtures as described below.
• estolides are esters resulting from secondary ester linkages between fatty acid chains, and every effort will be made herein to distinguish the actual estolide from the ester thereof.
• the oleic acid estolides for use in making the esters of this invention can be recovered by any conventional procedure. Typically, the preponderance of low boiling monomer fraction (unsaturated fatty acids and saturated fatty acids) and also dimer acids that may form are removed. In a preferred embodiment, reaction conditions will be selected such that no, or substantially no, dimer acids are produced in the course of reaction, with only estolides being formed and the residue fraction comprising substantially pure estolides .
• the oleic estolides are esterified by normal procedures, such as acid-catalyzed reduction with an appropriate alcohol.
• R and R 2 are not both hydrogen, and more preferably, neither R ⁇ nor R 2 is hydrogen. That is, it is preferred that the reactant alcohol be branched.
• the oleic estolide esters are selected from the group of isopropyl ester, 2- ethylhexyl ester and isostearyl ester. It is also preferred that the average value of n in Formula I is greater than about 0.5 and more preferably greater than about 1.0.
• esters which are characterized by: a viscosity at 40° C of at least 20 cSt and preferably at least about 32 cSt; a viscosity at 100° C of at least 5 cSt and preferably at least about 8 cSt; a viscosity index of at least 150; a pour point of less than -21° C and preferably at least -30° C; a volatility of less than 10% at 175° C; an insignificant ( ⁇ 10%) oxypolymerization in 30 min at 150° C in the micro oxidation test [Cvitkovic et al . , ASLE Trans .
• the oleic estolide esters of this invention have superior properties which render them useful as base stocks for biodegradable lubricant applications, such as crankcase oils, hydraulic fluids, drilling fluids, two-cycle engine oils and the like. Certain of these esters meet or exceed many, if not all, specifications for some lubricant end-use applications without the inclusion of conventional additives.
• the subject esters When used as a base stock, the subject esters can be admixed with an effective amount of other lubricating agents such as mineral or vegetable oils, other estolides, poly alpha olefins, polyol esters, oleates, diesters, and other natural or synthetic fluids .
• other lubricating agents such as mineral or vegetable oils, other estolides, poly alpha olefins, polyol esters, oleates, diesters, and other natural or synthetic fluids .
• any of a variety of conventional lubricant additives may optionally be incorporated into the base stock in an effective amount.
• these additives are detergents, antiwear agents, antioxidants, viscosity index improvers, pour point depressants, corrosion protectors, friction coefficient modifiers, colorants, antifoam agents, de ulsifiers and the like.
• effective amount as used herein is defined to mean any amount that produces a measurable effect for the intended purpose.
• an effective amount of an antiwear agent used in a lubricant composition is an amount that reduces wear in a machine by a measurable amount as compared with a control composition that does not include the agent .
• the reaction mixture was washed by mixing with a 10% solution of potassium hydrogen phosphate [50 lbs (23 kg) K 2 HP0 4 in 500 lbs (227 kg) city water] . After separation for 1 hour by settling, the pH was checked in both layers to be 5-6 and the water layer was decanted. After separation, the estolide ester was transferred to a kettle and vacuum dried to 105° C and 29 in of Hg to remove excess water and 2-ethylhexanol . The vacuum drying was followed by pressure filtration using 0.5% filter aid. The value of n in Formula I was 0.5.
• Example 3 Characterization of Physical Properties of 2-Ethylhexyl Oleic Estolide from Example 2.
• Biodegradation is usually tested using the Modified Sturm test, measuring the percent degradation in 28 days (OECD 301 B) . Biodegradabilities of the major basestocks are compared to that of nonesterified oleic estolide in Table I . It is expected that the 2-ethylhexyl ester of the oleic estolides would not have substantially different biodegradability than the nonesterified estolides .
• Viscometric properties determine the flow characteristics of the lubricants, their film thickness, and their ability to maintain a lubricating film under varying temperatures. In the lubricant industry these properties are determined by measuring kinematic viscosities using Cannon-Fenske viscometers and then assigned to viscosity grades. ISO 32 and ISO 46 grades are the most popular. Key viscometric properties of major basestocks used industrially to make biodegradable lubricants are compared to 2- ethylhexyl (2EH) ester of oleic estolide in Table II.
• 2EH 2- ethylhexyl
• estolide is its high viscosity index (VI) and viscosity grade of ISO 46. This compares to viscometric properties of oleates and vegetable oils . This estolide would not need thickeners which are necessary for tridecyl adipate or PAO 2. Presence of polymer based thickeners or viscosity modifiers may cause shear stability problems in formulated lubricants .
• Low temperature properties are important for lubricant pumpability, filterability, fluidity as well as cold cranking and startup .
• Pour point is the most common indicator of the low temperature behavior.
• Basestocks derived from vegetable oils usually cannot remain liquid in the cold storage test for more than 1 day, therefore, in addition to the pour point, the cold storage test is being developed by ASTM D02 to assess lubricants suitability.
• Key low temperature properties are compared in Table III.
• the estolide has significantly better low temperature properties than trioleates, vegetable oils or polyol esters of higher viscosities.
• Volatility is very important for lubricant vapor pressure, flammability, volatile burnoff and emissions. Volatility relates to the flash point, which is measured using Cleveland Open Cup test method. Micro oxidation data allows to quantify the volatility at particular temperatures, in this case 150° C (same range as hydraulic system or engine crankcase) . Key volatility properties are compared in Table IV. The estolides are much less volatile than low viscosity PAOs or adipates .
• Oxidative stability defines durability of lubricant and its ability to maintain functional properties during its use. Vegetable oil and oleate based lubricants usually suffer from poor oxidative stability. Micro oxidation is recognized in the lubricant industry as a technique to rank oxidative stabilities by quantifying oxypolymerization tendencies. Micro oxidation data are compared in Table V.
• Oxidative stability of estolide is comparable to that of fully saturated materials such as PAOs,. polyol esters and adipates . Vegetable oils and most of fluids derived from them are clearly inferior to the estolides.
• the 2-ethylexyl estolide ester has advantages over vegetable oils and oleates in its oxidative stability and low temperature properties, over low viscosity PAOs and adipates, in volatility, viscometric properties and biodegradability .
• the methyl, butyl, decyl, oleyl, isopropyl, isostearyl and branched C24 esters of oleic estolide were prepared substantially as described in Example 1 for the 2-ethylhexyl ester. These esters were evaluated for melting point, viscosity index, and viscosity at each of 100° F (38°C) , 40° C and 100° C in comparison with known vegetable oils, fatty acids and other estolides and vegetable oil derivatives . The results are given in Table VI .
• Oleic acid branched C24 ester 622 - 5 193 25.3 23.4 5
• Oleic estolide n 1.5 930 -31 148 453.9 404.9 40

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

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• 1998
  • 1998-11-16 ES ES98958608T patent/ES2272013T3/es not_active Expired - Lifetime
  • 1998-11-16 WO PCT/US1998/024469 patent/WO1999025794A1/en active IP Right Grant
  • 1998-11-16 DE DE69835694T patent/DE69835694T2/de not_active Expired - Lifetime
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