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
2001-05-31
2003-05-06
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...
C508S277000, C508S279000
Reexamination Certificate
active
06559107
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-alkyl-2-thione-1,3,4-thiadiazolidines.
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, R
2
and R
3
are independently selected from the group consisting of hydrocarbon or functionalized hydrocarbons of from 1 to 30 carbon atoms and hydrogen, and X is oxygen, sulfur or nitrogen.
In the above structural formulas, R
1
, R
2
, and R
3
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
, R
2
, and R
3
can be a straight or branched chain, a fully saturated or partially unsaturated hydrocarbon chain, preferably having from 1 to 40 carbon atoms, which may contain within it 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-alkyl-2-thione-1,3,4-thiadiazolidine 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-alkyl-2-thione-1,3,4-thiadiazolidine 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-alkyl-2-thione-1,3,4-thiadiazolidine compound of the formula:
wherein R
1
is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms, R
2
and R
3
are independently selected from the group consisting of hydrocarbon or functionalized hydrocarbons of from 1 to 30 carbon atoms and hydrogen, and X is oxygen, sulfur or nitrogen.
It is preferred that the 5-alkyl-2-thione-1,3,4-thiadiazolidine 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-alkyl-2-thione-1,3,4-thiadiazolidine 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, R
2
and R
3
are independently selected from the group consisting of hydrocarbon or functionalized hydrocarbons of from 1 to 30 carbon atoms and hydrogen, and X is oxygen, sulfur or nitrogen.
In the above structural formula, R
1
, R
2
, and R
3
are 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, 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, pentatriacontyl, tetracontyl, and the like, and isomers, e.g., 1-ethylpentyl, and mixtures thereof Where R
1
, R
2
, and/or R
3
are alkyl, they can be either a straight or a branched hydrocarbon chain, a fully saturated or partially unsaturated hydrocarbon chain, an alkylaryl, 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.
Additionally, R
1
and R
3
can be fused together as part of a spiro cyclic alkyl group CH
2
(CH
2
)
n
CH
2
, where n=1-4.
The use of the 5-alkyl-2-thione-1,3,4-thiadiazolidine compounds of this invention can improve the antifatigue, antiwear, and extreme pressure properties of a lubricant.
GENERAL SYNTHESIS OF ADDITIVES OF THIS INVENTION
The 5-alkyl-2-thione-1,3,4-thiadiazolidine compounds of the present invention can be synthesized as follows.
PROCEDURE A
In a 500 mL round bottom three-neck reaction flask equipped with a reflux condenser, mechanical stirrer, thermocouple, and nitrogen blanket is charged 100 mL of hexane solvent. The solvent can be any other liquid that is chemically inert towards the reactants and products that is also capable of azeotroping water, such as heptane, toluene, and xylenes. To the solvent is added aldehyde or
Crompton Corporation
Grandinetti Paul
Johnson Jerry D.
Reitenbach Daniel
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