Fuel and related compositions – Liquid fuels – Containing organic -c
Reexamination Certificate
1998-09-22
2001-09-25
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Containing organic -c
C044S398000
Reexamination Certificate
active
06293977
ABSTRACT:
This invention relates to additives for improving the lubricity of fuel oils such as diesel fuel oil. Fuel oil compositions including the additives of this invention exhibit improved lubricity and reduced engine system wear.
Concern for the environment has resulted in moves to significantly reduce the noxious components in emissions when fuel oils are burnt, particularly in engines such as diesel engines. Attempts are being made, for example, to minimise sulphur dioxide emissions. As a consequence attempts are being made to minimise the sulphur content of fuel oils. For example, although typical diesel fuel oils have in the past contained 1% by weight or more of sulphur (expressed as elemental sulphur) it is now considered desirable to reduce the level to 0.2% by weight, preferably to 0.05% by weight and, advantageously, to less than 0.01% by weight, particularly less than 0.001% by weight.
Additional refining of fuel oils, necessary to achieve these low sulphur levels, often results in reductions in the level of polar components. In addition, refinery processes can reduce the level of polynuclear aromatic compounds present in such fuel oils.
Reducing the level of one or more of the sulphur, polynuclear aromatic or polar components of diesel fuel oil can reduce the ability of the oil to lubricate the injection system of the engine so that, for example, the fuel injection pump of the engine fails relatively early in the life of an engine. Failure may occur in fuel injection systems such as high pressure rotary distributors, in-line pumps and injectors. The problem of poor lubricity in diesel fuel oils is likely to be exacerbated by the future engine system developments aimed at further reducing emissions, which will have more exacting lubricity requirements than present engines. For example, the advent of high pressure unit injectors is anticipated to increase the fuel oil lubricity requirement.
Similarly, poor lubricity can lead to wear problems in outer areas of the engine system or in other mechanical devices dependent for lubrication on the natural lubricity of fuel oil. Lubricity additives for fuel oils have been described in the art. WO 94/17160 describes an additive which comprises an ester of a carboxylic acid and an alcohol wherein the acid has from 2 to 50 carbon atoms and the alcohol has one or more carbon atoms. Glycerol monooleate is specifically disclosed as an example. Acids of the formula “R
1
(COOH)”, wherein R
1
is an aromatic hydrocarbyl group are generically disclosed by not exemplified.
U.S. Pat. No. 3,273,981 discloses a lubricity additive being a mixture of A+B wherein A is a polybasic acid, or a polybasic acid ester made by reacting the acid with C1-C5 monohydric alcohols; while B is a partial ester of a polyhydric alcohol and a fatty acid, for example glycerol monooleate, sorbitan monooleate or pentaerythritol monooleate. The mixture finds application in jet fuels.
U.S. Pat. No. 3,287,273 describes lubricity additives which are reaction products of a dicarboxylic acid and an oil-insoluble glycol. The acid is typically predominantly a dimer of unsaturated fatty acids such as linoleic or oleic acid, although minor proportions of the monomer acid may also be present. Alkane diols or oxa-alkane diols are primarily suggested as the glycol reactant. Example 7 discloses the reaction of one molar proportion of a dioic acid with 0.01 to 0.75 molar proportion of ethylene or propylene oxide.
UK 1,231,185 discloses a process for the preparation of &bgr;-hydroxy alkyl and aralkyl esters of unsaturated aliphatic dicarboxylic acids by reaction with vicinal epoxides of the general formula:
wherein R and R′ are each hydrogen, alkyl or aryl. The specific disclosure regarding the dicarboxylic acid reactant is limited to maleic, fumaric, glutaconic and 2-methylene alkane dicarboxylic acids such as itaconic acid and 2-methylene glutaric acid.
UK 1,552,280 discloses polycarboxylic acid -2-hydroxyalkyl esters and the use thereof as emulsifying agents in cosmetic emulsions. The esters have the general formula (—COOH)
n
wherein A represents an alkyl, cycloalkyl or aryl radical which is optionally substituted or interrupted by heteroatoms, R
1
, represents hydrogen or an alkyl radical having 1 to 12 carbon atoms, and R
2
represents an alkyl radical having 12 to 22 carbon atoms, n≧0 and m≧2, with the proviso that m≧n and the total of n+m≧3. The esters are manufactured by reacting the corresponding carboxylic acid and epoxide.
WO-A-94 06896 discloses oligomeric or polymeric reaction products of aromatic anhydrides and epoxides of the type (-A-B)
n
wherein n is equal to or greater than 1. The additives are described as improving the low temperature properties of distillate fuels.
U.S. Pat. No. 5,266,084 similarly concerns low temperature flow improvers for distillate fuels which may be formed from the alkenyl anhydrides or diacid equivalents and long-chain epoxides or diol equivalents. C
18
to C
24
alylated succinic anhydride is quoted as an example of the anhydride reactant.
There exists in the art a continual need for lubricity additives showing enhanced performance over existing materials, due not only to the development of engines with more exacting requirements, but also to the general demand from consumers and fuel producers for higher quality fuels.
In addition, there is a desire for additives to be handleable without the need for special operating measures. The extent to which an additive solidifies at lower ambient temperature (e.g. via crystallisation) determines the extent to which an additive may be handled in the absence of heating and mixing procedures. Many conventional additives require substantial mixing and heating prior to addition to the fuel, and such operations can cause processing delays and may make the use of such additives uneconomic in spite of their performance-enhancing effects.
SUMMARY OF THE INVENTION
In has not been found that certain products obtainable by the reaction of polycarboxylic acids with a certain molar amount of epoxides show excellent lubricity performance and handling properties.
In a first aspect, this invention provides the product obtainable by the reaction of at least one hydrocarbyl-substituted polycarboxylic acid with at least one epoxide, wherein one molar equivalent of carboxylic acid groups is reacted with 0.5 to 1.5 molar equivalents of epoxide groups.
In second and third aspects, this invention provides a process for making the product of the first aspect, comprising the reaction of at least one hydrocarbyl-substituted polycarboxylic acid with at least one epoxide, wherein one molar equivalent of carboxylic acid groups is reacted with 0.5 to 1.5 molar equivalents of epoxide groups, and the product obtained by such a process.
Further aspects of this invention include an additive composition comprising the product of the first or third aspects; an additive concentrate composition comprising either the product of the first or third aspects, or the additive composition, an optionally one or more additional additives, into a mutually-compatible solvent therefor; a fuel oil composition comprising fuel oil and either the product of the first or third aspects, or the additive composition or concentrate composition; an internal combustion engine system containing the fuel oil composition; the use of the product or the additive composition or concentrate to improve the lubricity of a fuel oil; and a method for improving fuel oil lubricity, comprising the addition thereto of the product or additive composition or concentrate composition.
The products defined under the first and third aspects of the invention provide, upon addition to low sulphur fuel oil, an improvement in fuel oil lubricity which can significantly exceed that obtainable from existing lubricity additives, and especially the dimer acid—glycol products disclosed in U.S. Pat. No. 3,287,273. The products also show excellent handleability at low temperature.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The or each acid from which the product is
Caprotti Rinaldo
Ledeore Christophe
Exxon Chemical Patents Inc.
Medley Margaret
LandOfFree
Lubricity additives for fuel oil compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lubricity additives for fuel oil compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lubricity additives for fuel oil compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485061