Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
2001-06-01
2003-04-22
Johnson, Jerry D. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
active
06551966
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is related to lubricants, especially lubricating oils, and, more particularly, to a class of ashless and non-phosphorus-containing anti-wear, anti-fatigue, and extreme pressure additives derived from 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazoles.
2. Description of Related Art
In developing lubricating oils, there have been many attempts to provide additives that impart antifatigue, antiwear, and extreme pressure properties thereto. Zinc dialkyldithiophosphates (ZDDP) have been used in formulated oils as antiwear additives for more than 50 years. However, zinc dialkyldithiophosphates give rise to ash, which contributes to particulate matter in automotive exhaust emissions, and regulatory agencies are seeking to reduce emissions of zinc into the environment. In addition, phosphorus, also a component of ZDDP, is suspected of limiting the service life of the catalytic converters that are used on cars to reduce pollution. It is important to limit the particulate matter and pollution formed during engine use for toxicological and environmental reasons, but it is also important to maintain undiminished the antiwear properties of the lubricating oil.
In view of the aforementioned shortcomings of the known zinc and phosphorus-containing additives, efforts have been made to provide lubricating oil additives that contain neither zinc nor phosphorus or, at least, contain them in substantially reduced amounts.
Illustrative of non-zinc, i.e., ashless, non-phosphorus-containing lubricating oil additives are the reaction products of 2,5-dimercapto-1,3,4-thiadiazoles and unsaturated mono-, di-, and tri-glycerides disclosed in U.S. Pat. No. 5,512,190 and the dialkyl dithiocarbamate-derived organic ethers of U.S. Pat. No. 5,514,189.
U.S. Pat. No. 5,512,190 discloses an additive that provides antiwear properties to a lubricating oil. The additive is the reaction product of 2,5-dimercapto-1,3,4-thiadiazole and a mixture of unsaturated mono-, di-, and triglycerides. Also disclosed is a lubricating oil additive with antiwear properties produced by reacting a mixture of unsaturated mono-, di-, and triglycerides with diethanolamine to provide an intermediate reaction product and reacting the intermediate reaction product with 2,5-dimercapto-1,3,4 thiadiazole.
U.S. Pat. No. 5,514,189 discloses that dialkyl dithiocarbamate-derived organic ethers have been found to be effective antiwear/antioxidant additives for lubricants and fuels.
U.S. Pat. Nos. 5,084,195 and 5,300,243 disclose N-acyl-thiourethane thioureas as antiwear additives specified for lubricants or hydraulic fluids.
The disclosures of the foregoing references are incorporated herein by reference in their entirety.
SUMMARY OF THE INVENTION
The present invention relates to compounds of the formula
wherein R
1
is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
In the above structural formulas, R
1
can be a straight or branched chain, fully saturated or partially unsaturated, hydrocarbon moiety, preferably alkyl or alkenyl having from 1 to 30 carbon atoms, e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, oleyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, triacontyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, oleenyl, nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricosenyl, tetracosenyl, pentacosenyl, triacontenyl, and the like, and isomers and mixtures thereof Additionally, R
1
can be a straight or branched chain, a fully saturated or partially unsaturated hydrocarbon chain, preferably having from 1 to 30 carbon atoms, within which may be ester groups or heteroatoms, such as, oxygen, sulfur, and nitrogen, which may take the form of ethers, polyethers, sulfides, amines, and amides. This is what is meant by “functionalized hydrocarbon.”
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of this invention are useful as ashless, non-phosphorus-containing antifatigue, antiwear, extreme pressure additives for lubricating oils.
The present invention also relates to lubricating oil compositions comprising a lubricating oil and a functional property-improving amount of at least one 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compound of the above formulas. More particularly, the present invention is directed to a composition comprising:
(A) a lubricant, and
(B) at least one 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compound of the formula:
wherein R
1
is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
It is preferred that the 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole is present in the compositions of the present invention in a concentration in the range of from about 0.01 to about 10 wt %.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of the present invention are compounds of the formula:
wherein R
1
is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
In the above structural formula, R
1
is preferably an alkyl moiety of 1 to 30 carbon atoms, more preferably of 1 to 22 carbon atoms, most preferably of 1 to 10 carbon atoms, and can have either a straight chain or a branched chain, a fully saturated or partially unsaturated hydrocarbon chain, alkylaryl, e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, oleyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, triacontyl, dodecyl phenyl, octyl phenyl, and the like, and isomers, e.g., 1-ethylpentyl, 2-ethylhexyl, and mixtures thereof. Where R
1
is alkyl, it can be either a straight or a branched hydrocarbon chain, a fully saturated or partially unsaturated hydrocarbon chain, wherein said chains may contain ester groups or heteroatoms, such as oxygen and/or sulfur and/or nitrogen, which may take the form of ethers, polyethers, sulfides, amines, amides, and the like. As employed herein, the term “alkyl” is also intended to include “cycloalkyl.” Where the alkyl is cyclic, it preferably contains from 3 to 9 carbon atoms, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and the like. Cycloalkyl moieties having 5 or 6 carbon atoms, i.e., cyclopentyl or cyclohexyl, are more preferred.
The use of the 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of this invention can improve the antifatigue, antiwear, and extreme pressure properties of a lubricant.
General Synthesis of Additives of this Invention
The following is a typical preparation of a 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole using oleyl hydrazide as the starting raw material to make 5-heptadecenyl-2-mercapto-1,3,4-oxadiazole.
In a 50 mL flask equipped with a magnetic stirring bar, nitrogen blanket with a caustic trap to absorb evolving hydrogen sulfide gas by-product, reflux condenser, thermocouple, and heating mantle, is charged 5 mL of triethylamine and 2.5 grams of carbon disulfide. To the reaction media, under a nitrogen blanket with stirring, is added dropwise a solution of 7.0 grams of oleyl hydrazide dissolved in 10 mL of warm triethylamine over a 10 minute period. This results in an immediate 20 to 25° C. exotherm to 42° C. The temperature is slowly raised to 90° C. and held for 15 hrs. with the evolution of hydrogen sulfide. The reaction media are then placed under 100 mm Hg vacuum for one hour at 130° C. to remove any residual hydrogen sulfide and triethylamine solvent. The final product is an orange liquid at room temperature which slowly solidifies to a paste.
Use with Other Additives
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole additives of this invention can be used as either a partial or complete replacement for the zinc dialkyldithiophosphates currently used. T
Crompton Corporation
Grandinetti Paul
Johnson Jerry D.
Reitenbach Daniel
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