Fuel and related compositions – Liquid fuels – Containing organic -c
Reexamination Certificate
1999-11-04
2004-04-13
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Containing organic -c
C560S067000
Reexamination Certificate
active
06719814
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a lubricity additive, a process for preparing lubricity additives, and low-sulphur, middle distillate fuel oil compositions containing the same.
BACKGROUND OF THE INVENTION
International application WO 98/01516 concerns acids have excellent lubricity behaviour when used in a fuel oil composition comprising a major amount of a low-sulphur, middle distillate fuel oil.
International application WO 98/16596 concerns specific substituted aromatic ester compounds useful as lubricity additive for middle distillate fuel compositions comprising a major proportion of a diesel fuel oil having a sulphur concentration of 0.2% by weight or less, and a minor proportion of the additive. The specific substituted aromatic ester compounds are produced by esterification of an acid similar to those of WO 98/01516 with a mono- or polyhydroxy alcohol. Typical examples are based on the esterification of a C
18
-alkyl salicylic acid with ethylene glycol (conversion of the acid to the ester product up to a degree of 45%), or by an epoxy ring-opening reaction using glycidol (conversion up to 80.4%).
It would be desirable if lubricity additives could be found with even better properties.
SUMMARY OF THE INVENTION
Accordingly, the invention provides a lubricity additive in the form of an ester of an acid and an alcohol, wherein the acid is an aromatic mono-, di- or polyhydric, mono-, di- or polycarboxylic acid or mixture thereof, which may be alkylated and/or alkoxylated and wherein the alkyl and/or alkoxy groups, if any, are independently selected from groups having from 1 to 30 carbon atoms, characterised in that
(a) the alcohol is glycerol, and
(b) the mole percent of acid groups in the lubricity additive is less than 10%, based on the total of acid and ester groups. Preferably the mole percent of acid groups in the lubricity additive is less than 5%.
The invention also provides a process for preparing the lubricity additive characterised in that
(a) the alcohol is glycerol, and
(b) the esterification is carried out in the presence of catalyst selected from boric acid or a titanium alkoxide.
The invention also provides a middle distillate fuel oil having a sulphur concentration of 0.2% by weight or less, and a minor portion of the lubricity additive.
DETAILED DESCRIPTION OF THE INVENTION
The lubricity additives according to the present invention have been produced by esterification, wherein the degree of esterification is at least 90%, preferably at least 95%, and more preferably at least 97%, by weight of the original amount of acid or derivative reactant acid. These esters may also be identified by their residual acid value, provided the (average) molecular weight of the acid is known. For instance, if the lubricity additive is produced from a mixture of acids having an average molecular weight of 400 with a corresponding acid value of 2.5 mmole/g, then the lubricity additive will have a residual acid value of less than 0.25 mmole/g.
The lubricity additives therefore differ from those of WO 98/16596 in that their residual acid values are substantially lower, and in the selection of glycerol as alcohol feed. Given the already outstanding performance of the acids and the—slightly—underscoring performance of the glycidol ester D in WO 98/16596 vis-à-vis the—more acid containing—glycol esters A, B and C in WO 98/16596, a further improvement for the lubricity additives of the present invention could not be expected.
The acid, the ester, the process and the fuel composition will now be discussed in further detail.
The Acid
The acid from which the ester is derived may be an aromatic mono-, di- or polyhydric, mono-, di- or polycarboxylic acid wherein the carboxyl and hydroxyl groups are attached to the aromatic nucleus. The aromatic nucleus may be monocyclic, bicyclic or polycyclic, e.g., a benzene ring or a naphthalene ring. Besides, the aromatic nucleus may be contain heterogeneous elements, e.g., nitrogen and oxygen atoms. The aromatic nucleus is preferably a benzene ring. The presence of at least one hydroxyl group (in contrast to esters based on benzoic acid) has been found essential. More than 1 hydroxyl group may be present, but the presence of one hydroxyl group is preferred. Similarly, the presence of one arboxyl group—rather than 2 or more—is preferred.
The aromatic nucleus may be substituted with one or more groups selected independently from alkyl and alkoxy groups of 1 to 30 carbon atoms. Preferred acids are those in which whenever there are less than three groups selected from alkyl and alkoxy groups attached to the aromatic nucleus, there is at least one group selected from alkyl and alkoxy groups of 2 to 30 carbon atoms attached to said nucleus. Preferably, the acid is an alkyl salicylic acid containing one or two alkyl groups of 1—30 carbon atoms. The or each alkyl or alkoxy group in the acid has preferably 8 to 22 carbon atoms, more preferably 8 to 18 carbon atoms.
The acids from which the ester is derived are either known compounds or can be prepared by methods analogous to methods used for preparing known compounds, as will readily be appreciated by those skilled in the art.
Preferred alkyl salicylic acids may be very readily be prepared by the methods described in UK 1146925. (In that patent, the alkyl salicylic acids are intermediates in the preparation of polyvalent metal salts used as dispersants in lubricant compositions).
The Ester
The ester is prepared by esterifying the acid directly with the alcohol in the presence of a catalyst and distilling off the water formed.
The Process
The preparation of esters of an aromatic acid via direct esterification is known to those skilled in the art. For instance, Romanian patent RO 0102886 and U.S. Pat. No. 4,098,708 describe processes using p-toluenesulphonic acid as catalyst; RO 093627 describes processes using sulphuric acid as catalyst; French patent FR 2200241 describes processes using p-toluenesulphonic acid or sulphuric acid as catalyst; Russian Journal Maslo-zhir. Prom-st, (1986), (8), 25-6, J. Chem. Educ., (1996), 73(2), 173-5 and Chinese patent CN 1056488 describe processes using boric acid as catalyst; Indian patent 167688 describes processes using molecular sieve as catalyst. Also, WO 98/16596 describes methods of making esters from salicylic acid and polyols. There is no indication in any of the above documents what process and/or catalyst might be used in order to produce lubricity additives that outperform those of WO 98/16596.
In the present invention, we have found that processes using boric acid or titanium alkoxides as catalyst and glycerol as alcohol reactant lead to the highest conversion of the acid to ester, typically as high as 99.9%.
Preferred titanium alkoxides are based on alkoxy groups having 1 to 10 carbon atoms, preferably based on alkoxy groups having 2 to 6 carbon atoms. A suitable titanium alkoxide is, for instance, titanium(IV) butoxide.
The process is ordinarily carried out at temperatures 30 of from 50 to 250° C. The process is preferably carried out at temperatures of from 100 to 250° C. and especially of from 125 to 250° C.
The reaction may be carried out with or without a diluent. Typically it is carried out in the presence of an inert, non-polar liquid organic diluent, for example, hydrocarbons such as naphtha, mineral oil, toluene, xylene (ortho-, meta-, para- or a mixture thereof).
The ratio of OH equivalent of glycerol over COOH equivalent of acid will at least be 1, typically ranging from 1 to 10, preferably from 1 to 5.
The low-sulphur, Middle Distillate Fuel Oil Composition Fuel oil compositions in accordance with the invention may be prepared by a process which comprises admixing the additive or an additive concentrate containing the additive with the fuel oil.
The ester is preferably present in an amount in the range 50 to 600 ppmw, more preferably 50 to 500 ppmw, most preferably 150 to 300 ppmw (“ppmw” is parts per million by weight), based on the total weight of the fuel composition. Also mixtures of esters may be used.
The middle distillate fuel
Infineum International LTD
Medley Margaret
LandOfFree
Lubricity additive, process for preparing lubricity... 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 additive, process for preparing lubricity..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lubricity additive, process for preparing lubricity... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3244018