Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
2000-12-06
2002-03-19
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S551000, C508S555000, C560S174000
Reexamination Certificate
active
06358896
ABSTRACT:
This invention relates to lubricating oils particularly useful for passenger car engines. More particularly, the invention relates to lubricating oil compositions which exhibit improvements in fuel economy and fuel economy retention through use of certain friction modifiers.
The present invention is based on the discovery that the use of certain derivatives of alkyl acetoacetates as friction modifiers can provide increases in fuel economy as well as fuel economy retention as observed by coefficient of friction studies for lubricating oils containing these additives.
U.S. Pat. No. 4,839,072, issued Jun. 13, 1989 to Gutierrez et al. discloses the use of a polyolefinic succinimide polyamine alkyl acetoacetate adducts as additives for lubricants, including use as friction modifiers.
In accordance with the invention there has been discovered a lubricating oil composition which comprises an oil of lubricating viscosity and a friction modifier selected from the group consisting of
(a) a keto-amide formed by reacting an alkyl acetoacetate with a C
10
-C
24
aliphatic primary amine; and
(b) a keto-ester formed by transesterification of an alkyl acetoacetate with a compound selected from the group consisting of C
10
-C
24
aliphatic primary alcohols, C
10
-C
24
hydroxy-substituted aliphatic hydrocarbyl sulfides, ethoxylated C
10
-C
24
primary aliphatic amines and ethoxylated C
10
-C
24
primary aliphatic ether amines.
The keto-esters referred to in subparagraph (b) above are all considered to be novel compounds and thus constitute further embodiments of this invention.
The alkyl acetoacetates used in forming the friction modifiers of the present invention may be represented by the formula R
1
C(:O)CH
2
C(:O)OR
2
wherein R
1
and R
2
are C
1
-C
12
(meaning 1 to 12 carbon atoms) alkyl, preferably methyl or ethyl. A preferred compound for use in preparing the friction modifiers in accordance with the present invention is ethyl acetoacetate (EAA) which normally exists as a tautomer in both keto and enol forms. Methyl acetoacetate is also preferred.
The keto amide friction modifier is formed by reacting the alkyl acetoacetate with a C
10
-C
24
aliphatic primary amine where the C
10
-C
24
hydrocarbyl is branched or straight chain alkyl or alkenyl. This reaction may be carried out at about 100° C. for about 2 hours and for another 2 hours at about 150° C. Approximately, equimolar amounts of amine and alkyl acetoacetate are employed. Preferred amines are a mixture of C
11
-C
14
tertiary alkyl primary amines (particularly those sold as Primene 81R) as well as oleyl amine.
The second general category of friction modifiers for use in the present invention are the keto esters formed by transesterification of an alkyl acetoacetate. These friction modifiers are considered novel compounds. The first keto ester friction modifier is formed by the transesterification of an alkyl acetoacetate with a C
10
-C
24
aliphatic primary alcohol. The C
10
-C
24
group may comprise a branched or straight chain alkyl or alkenyl group. This may be prepared by reacting equimolar quantities of the alcohol and the acetoacetate at about 100° C. under nitrogen over a period of about 4 hours. The preferred compound is the product formed by the transesterification of ethyl acetoacetate with oleyl alcohol.
The next friction modifier is that formed by the transesterification of a C
10
-C
24
hydroxy-substituted aliphatic hydrocarbyl (branched or straight chain alkyl or alkenyl) sulfide with an alkyl acetoacetate. This reaction may be carried out by reacting equimolar quantities at 100° C. for about 2 hours and then for an additional 2 hours at about 150° C. Particularly preferred is the friction modifier formed by the transesterification of 2-hydroxyethyldodecyl sulfide with ethyl acetoacetate.
The next category of friction modifier in accordance with this invention is the product formed by the transesterification of an ethoxylated C
10
-C
24
branched or straight chain alkyl or alkenyl primary aliphatic amine with an alkyl acetoacetate. The degree of ethoxylation will be 1-6, preferably about 2, moles of ethylene oxide per mole of amine. The product may be formed by reacting a molar equivalent of alkyl acetoacetate per each molar equivalent of hydroxy functionality in the ethoxylated amine. This reaction may be carried out at 2 hours at 100° C. and for an additional 2 hours at 150° C. until the distillation of ethanol comes to an end. The preferred embodiment is a product formed by the transesterification of the 2 mole ethoxylate of di-tallow amine with ethyl acetoacetate.
The last friction modifier embodiment of this invention is the product formed by the transesterification of ethoxylated ether primary aliphatic C10-C24 straight chain or branched alkyl or alkenyl amine with an alkyl acetoacetate. The degree of ethoxylation will be 1-6, preferably about 2, moles of ethylene oxide per mole of ether amine. The molar ratio is again 1 molar equivalent of alkyl acetoacetate per each molar equivalent of hydroxyl functionality in the ether amine. This reaction is also carried out at 100° C. for about 2 hours and for an additional 2 hours at 150° C. until the ethanol distillation ceases. The preferred embodiment for this friction modifier is the product formed by the transesterification of the 2 mole ethoxylate of a mixture of C
16
-C
18
alkyl primary ether amines and ethyl acetoacetate.
Generally speaking, these friction modifiers are used in lubricating oils in amount from 0.05 to 2%, preferably 0.02 to 1% and most preferably 0.3 to 0.5% by weight.
Natural oils useful as basestocks in this invention include animal oils and vegetable oils (e.g., castor, lard oil) liquid petroleum oils and hydrorefined, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic and mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful base oils.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., are a class of known synthetic lubricating oils useful as basestocks in this invention. These are exemplified by polyoxyalkylene polymers prepared by polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-poly isopropylene glycol ether having an average molecular weight of 1000, diphenyl ether of poly-ethylene glycol having a molecular weight of 500-1000, diethyl ether of polypropylene glycol having a molecular weight of 1000-1500); and mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C
3
-C
8
fatty acid esters and C
13
Oxo acid diester of tetraethylene glycol.
Another suitable class of synthetic lubricating oils useful in this invention comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenyl malonic acids) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.
Esters useful as synthetic oils also include those made from C
5
to C
12
monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxysiloxane oils and silicate oils comprise another usef
Gutierrez Antonio
Hartley Rolfe J.
Infineum International Ltd.
McAvoy Ellen M.
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