U.S. patent number RE29,488 [Application Number 05/728,398] was granted by the patent office on 1977-12-06 for fuel compositions and additive mixtures for alleviation of exhaust gas catalyst plugging.
This patent grant is currently assigned to Ethyl Corporation. Invention is credited to Marcelian F. Gautreaux.
United States Patent |
RE29,488 |
Gautreaux |
December 6, 1977 |
Fuel compositions and additive mixtures for alleviation of exhaust
gas catalyst plugging
Abstract
Gasoline compositions and additive mixtures of
carboxymethoxysuccinic acid, its salts, esters, or other
derivatives in amount sufficient to alleviate the plugging of
certain catalysts being used in an engine exhaust system to lower
the amount of undesirable constituents in exhaust gas from an
engine being operated on gasoline containing a cyclopentadienyl
manganese antiknock.
Inventors: |
Gautreaux; Marcelian F. (Baton
Rouge, LA) |
Assignee: |
Ethyl Corporation (Richmond,
VA)
|
Family
ID: |
23920908 |
Appl.
No.: |
05/728,398 |
Filed: |
September 30, 1976 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
483641 |
Jun 27, 1974 |
03926580 |
Dec 16, 1975 |
|
|
Current U.S.
Class: |
44/360 |
Current CPC
Class: |
B01D
53/86 (20130101); C10L 1/14 (20130101); C10L
10/06 (20130101); C10L 10/10 (20130101); C10L
10/04 (20130101); C10L 1/1883 (20130101); C10L
1/19 (20130101); C10L 1/191 (20130101); C10L
1/205 (20130101); C10L 1/2225 (20130101); C10L
1/305 (20130101) |
Current International
Class: |
C10L
1/10 (20060101); C10L 1/14 (20060101); B01D
53/86 (20060101); C10L 1/18 (20060101); C10L
1/22 (20060101); C10L 1/30 (20060101); C10L
1/20 (20060101); C10L 001/18 () |
Field of
Search: |
;44/68,70 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wyman; Daniel E.
Assistant Examiner: Harris-Smith; Mrs. Y.
Attorney, Agent or Firm: Johnson; Donald L. Linn; Robert A.
Montgomery; Willard G.
Claims
I claim:
1. As a composition of matter, a gasoline for an internal
combustion engine comprising
i. about 0.005 -10 grams of manganese per gallon as a
cyclopentadienyl manganese tricarbonyl wherein said
cyclopentadienyl group is a hydrocarbon group containing 5-17
carbon atoms, and
ii. amount sufficient to reduce the plugging of an exhaust gas
catalyst of a compound having the general formula: ##STR6## wherein
R is independently selected from hydrogen and hydrocarbyl
radicals.
2. The composition of claim 1 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
3. The composition of claim 1 wherein each R is methyl.
4. The composition of claim 1 wherein each R is ethyl.
5. The composition of claim 1 wherein said cyclopentadienyl
manganese tricarbonyl is methylcyclopentadienyl manganese
tricarbonyl.
6. Gasoline comprising
i. a cyclopentadienyl manganese tricarbonyl wherein said
cyclopentadienyl group is a hydrocarbon group containing 5-17
carbon atoms antiknock compound in an amount sufficient to improve
the antiknock characteristics of said gasoline, and
ii. a compound in an amount sufficient to reduce the plugging of a
noble metal exhaust gas catalyst, said compound having the general
formula: ##STR7## wherein R is independently selected from hydrogen
and a hydrocarbyl radical.
7. The gasoline of claim 6 wherein R is a lower alkyl group having
from 1 to about 10 carbon atoms.
8. The gasoline of claim 6 wherein each R is methyl.
9. The gasoline of claim 6 wherein each R is ethyl.
10. The gasoline of claim 6 wherein R is an aryl group.
11. The gasoline of claim 10 wherein said aryl group is a phenyl
group of up to 10 carbon atoms.
12. A substantially lead-free gasoline (for use with a noble metal
exhaust gas purification catalyst, said gasoline comprising
i. a cyclopentadienyl manganese tricarbonyl wherein said
cyclopentadienyl group is a hydrocarbon group containing 5-17
carbon atoms antiknock in an amount sufficient to improve the
antiknock characteristics of said gasoline, and
ii. a compound in an amount sufficient to reduce plugging of said
noble metal exhaust gas purification catalyst, said compound having
the general formula: ##STR8## wherein R is independently selected
from hydrogen and hydrocarbyl radicals.
13. The gasoline of claim 12 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
14. The gasoline of claim 12 wherein each R is methyl.
15. The gasoline of claim 12 wherein each R is ethyl.
16. The gasoline of claim 12 wherein said hydrocarbyl radical is an
aryl group.
17. The gasoline of claim 16 wherein said aryl group is a phenyl
group of up to about 10 carbon atoms.
18. A gasoline for use with a noble metal exhaust gas purification
catalyst said gasoline comprising
i. a cyclopentadienyl manganese tricarbonyl wherein said
cyclopentadienyl group is a hydrocarbon group containing 5-17
carbon atoms antiknock in an amount sufficient to improve the
antiknock characteristics of said gasoline, and
ii. a compound in an amount sufficient to reduce the plugging of
said noble metal exhaust gas catalyst, said compound having the
formula: ##STR9##
19. As a composition of matter an additive fluid for low lead or
essentially lead-free gasoline comprising a cyclopentadienyl
manganese tricarbonyl wherein said cyclopentadienyl group is a
hydrocarbon group containing 5-17 carbon atoms antiknock, and an
amount sufficient to reduce the plugging of an exhaust gas catalyst
of a compound having the general formula: ##STR10## wherein R is
independently selected from hydrogen and hydrocarbyl radicals.
20. The composition of claim 19 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
21. The composition of claim 19 wherein each R is methyl.
22. The composition of claim 19 wherein each R is ethyl.
23. The composition of claim 19 wherein R is an aryl group.
24. The composition of claim 23 wherein said aryl group is a phenyl
group of up to about 10 carbon atoms.
25. The composition of claim 19 wherein said cyclopentadienyl
manganese tricarbonyl is methylcyclopentadienyl manganese
tricarbonyl.
26. The composition of claim 25 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
27. The composition of claim 26 wherein said lower alkyl group is
ethyl.
28. The composition of claim 26 wherein said lower alkyl group is
methyl.
29. The gasoline of claim 18 wherein said cyclopentadienyl
manganese tricarbonyl is methylcyclopentadienyl manganese
tricarbonyl.
30. The gasoline of claim 12 wherein said cyclopentadienyl
manganese tricarbonyl is methylcyclopentadienyl manganese
tricarbonyl.
31. The gasoline of claim 30 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
32. The gasoline of claim 31 wherein said lower alkyl group is
methyl.
33. The gasoline of claim 31 wherein said lower alkyl group is
ethyl.
34. The gasoline of claim 6 wherein said cyclopentadienyl manganese
tricarbonyl is methylcyclopentadienyl manganese tricarbonyl.
35. The gasoline of claim 34 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
36. The gasoline of claim 35 wherein sid lower alkyl group is
methyl.
37. The gasoline of claim 35 wherein said lower alkyl group is
ethyl.
38. The composition of claim 5 wherein R is a lower alkyl group
having from 1 to about 10 carbon atoms.
39. The composition of claim 38 wherein said lower alkyl group is
ethyl.
40. The composition of claim 38 wherein said lower alkyl group is
methyl.
Description
BACKGROUND OF THE INVENTION
Cyclopentadienyl manganense compounds are excellent antiknocks in
gasoline used to operate internal combustion engines. These
manganese compounds have proved to be especially beneficial in
solving some of the problems present when low-lead or lead-free
gasolines are used with internal combustion engines. Use of such
compounds as antiknocks is described in U.S. Pat. Nos. 2,818,417;
2,839,552; and 3,127,351, incorporated herein by reference. Not
only are these compounds effective antiknock compounds, but it has
also been found that they do not adversely affect the activity of
oxidation metal catalysts used to decrease the amount of
undesirable constituents in engine exhaust gas. Under some
operating conditions it has been found that, although the manganese
antiknocks do not lessen the activity of the exhaust gas catalyst,
they can interact in some manner at the surface of the catalyst bed
leading to a reduction in the size of the openings into the bed
thereby causing an increase in exhaust back-pressure and a decrease
in the effective life of said catalysts. The present invention
provides a simple effective means of alleviating this problem.
It has been previously suggested that the addition of triethyl
citrate to gasoline mixes containing organomanganese antiknocks
tends to reduce catalyst plugging. The use of triethyl citrate,
however, has proved to be of rather limited success in reducing the
plugging problem, especially at higher temperatures.
SUMMARY
According to the present invention, the useful life of an exhaust
gas catalyst in an exhaust system of an engine operating on
gasoline containing a cyclopentadienyl manganese antiknock is
greatly increased by providing new additive fluids and gasoline
compositions which contain an amount of carboxymethoxysuccinic acid
or gasoline soluble derivative thereof sufficient to alleviate
plugging of the exhaust gas catalyst.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The essence of the present invention resides in reducing the
plugging of oxidation metal catalytic apparatus for purifying
exhaust gases of internal combustion engines which burn a gasoline
containing an organomanganese compound. This reduction in plugging
is effected by the addition of carboxymethoxysuccinic acid, its
gasoline soluble esters, salts, or other gasoline soluble
derivatives to the gasoline. Accordingly, a preferred embodiment is
a gasoline suitable for use in an internal combustion engine and
containing an amount of organomanganese compound, preferably a
cyclopentadienyl manganese tricarbonyl, sufficient to increase its
antiknock effectiveness, and also containing an amount sufficient
to prevent plugging of the catalyst of carboxymethoxysuccinic acid,
or its gasoline soluble salts, esters, and other gasoline soluble
derivatives.
A further embodiment of the present invention is a gasoline
additive fluid composition comprising an organomanganese compound,
preferably a cyclopentadienyl manganese tricarbonyl, and most
preferably methylcyclopentadienyl manganese tricarbonyl, in an
amount sufficient to improve the antiknock characteristics of the
gasoline and carboxymethoxysuccinic acid, or its gasoline soluble
salts, esters, and other gasoline soluble derivatives, preferably
the mono-, di-, and triesters of carboxymethoxysuccinic acid, and
most preferably the triesters of carboxymethoxysuccinic acid, in an
amount sufficient to reduce catalyst plugging.
Since the invention also embodies the operation of an internal
combustion engine in a manner which results in reduced plugging of
the catalyst, a still further embodiment is a method of operating
an internal combustion engine using a gasoline containing an
organomanganese, preferably a cyclopentadienyl manganese
tricarbonyl, and most preferably methylcyclopentadienyl manganese
tricarbonyl antiknock in a manner which results in substantial
reduction in the plugging of the catalyst, said method comprising
(a) supplying to the fuel induction system of said engine a
gasoline containing an organomanganese antiknock and a gasoline
soluble solution of carboxymethoxysuccinic acid, its salts, esters,
or other gasoline soluble derivatives, (b) mixing said gasoline
with air, (c) inducting the mixture into the combustion chambers of
said engine, (d) compressing said mixture, (e) igniting said
compressed mixture, and (f) exhausting the resultant combustion
products which have a reduced plugging effect on the catalyst
.Iadd., .Iaddend.through said catalyst.
Liquid hydrocarbon fuels of the gasoline boiling range are mixtures
of hydrocarbons having a boiling range of from about 80.degree. F
to about 430.degree. F. Of course, these mixtures can contain
individual constituents boiling above or below these figures. These
hydrocarbon mixtures contain aromatic hydrocarbons, saturated
hydrocarbons and olefinic hydrocarbons. The bulk of the hydrocarbon
mixture is obtained by refining crude petroleum by either straight
distillation or through the use of one of the many known refining
processes, such as thermal cracking, catalytic cracking, catalytic
hydroforming, catalytic reforming, and the like. Generally, the
final gasoline is a blend of sticks obtained from several refinery
processes. The final blend may also contain hydrocarbons made by
other procedures such as allkylate made by the reaction of C.sub.4
olefins and butanes using an acid catalyst such as sulfuric acid or
hydrofluoric acid.
Preferred gasolines are those having a Research Octane Number of at
least 85. A more preferred Research Octane Number is 90 or greater.
It is also preferred to blend the gasoline such that it has a
content of aromatic hydrocarbons ranging from 10 to about 60 volume
percent, an olefinic hydrocarbon content ranging from 0 to about 30
volume percent, and a saturate hydrocarbon content ranging from
about 40 to 80 volume percent, based on the whole gasoline.
In order to obtain fuels having properties required by modern
automotive engines, a blending procedure is generally followed by
selecting appropriate blending stocks and blending them in suitable
proportions. The required octane level is most readily accomplished
by employing aromatics (e.g., BTX, catalytic reformate or the
like), alkylate (e.g., C.sub.6-9 saturates made by reacting C.sub.4
olefins with isobutane using a HF or H.sub.2 SO.sub.4 catalyst), or
blends of different types.
The balance of the whole fuel may be made up of other components
such as other saturates, olefins, or the like. The olefins are
generally formed by using such procedures as thermal cracking,
catalytic cracking and polymerization. Dehydrogenation of paraffins
to olefins can supplement the gaseous olefins occurring in the
refinery to produce feed material for either polymerization or
alkylation processes. The saturated gasoline components comprise
paraffins and naphthenes. These saturates are obtained from (1)
virgin gasoline by distillation (straight run gasoline), (2)
alkylation processes (alkylates) and (3) isomerization procedures
(conversion of normal paraffins to branched chain paraffins of
greater octane quality). Saturated gasoline components also occur
in so-called natural gasolines. In addition to the foregoing,
thermally cracked stocks, catalytically cracked stocks and
catalytic reformates contain saturated components.
The classification of gasoline components into aromatics, olefins
and saturates is well recognized in the art. Procedures for
analyzing gasolines and gasoline components for hydrocarbon
composition have long been known and used. Commonly used today is
the FIA analytical method involving fluorescent indicator
adsorption techniques. These are based on selective adsorption of
gasoline components on an activated silica gel column, the
components being concentrated by hydrocarbon type in different
parts of the column. Special fluorescent dyes are added to the test
sample and are also selectively separated with the sample fraction
to make the boundaries of the aromatics, olefins and saturates
clearly visible under ultraviolet light. Further details concerning
this method can be found in "1969 Book of ASTM Standards," Jan.
1969 Edition, under ASTM Test Designation D 1319-66T.
The motor gasolines used in formulating the improved fuels of this
invention generally have initial boiling points ranging from about
80.degree. to about 105.degree. F. and final boiling points ranging
from about 380.degree. to about 430.degree. F. as measured by the
standard ASTM distillation procedure (ASTM D-86). Intermediate
gasoline fractions boil away at temperatures within these
extremes.
From the standpoint of minimizing atmospheric pollution to the
greatest extent possible, it is best to keep the olefin content of
the fuel as low as can be economically achieved as olefins
reportedly give rise to smog-forming emissions, especially from
improperly adjusted vehicular engines. Accordingly, in the
preferred base stocks of this invention the olefin content will not
exceed about 10 volume percent and the most particularly preferred
fuels will not contain more than about 5 percent olefins. Table I
illustrates the hydrocarbon type makeup of a number of particularly
preferred fuels for use in this invention.
TABLE I ______________________________________ Hydrocarbon Blends
of Particularly Preferred Base Fuels Volume Percentage Fuel
Aromatice Olefins Saturates ______________________________________
A 35.0 2.0 63.0 B 40.0 1.5 58.5 C 20.0 2.5 77.5 D 33.5 1.0 65.5 E
36.5 2.5 61.0 F 43.5 1.5 55.0 G 49.5 2.5 48.0
______________________________________
It is also desirable to utilize base fuels having a low sulfur
content as the oxides of sulfur tend to contribute an irritating
and choking character to smog and other forms of atmospheric
pollution. Therefore, to the extent it is economically feasible,
the fuel will contain not more than about 0.1 weight percent of
sulfur in the form of conventional sulfur-containing impurities.
Fuels in which the sulfur content is no more than about 0.02 weight
percent are especially preferred for use in this invention.
Normally the gasoline to which this invention is applied is
lead-free or substantially lead-free, although small amounts of
organolead additives usually employed to give fuels of improved
performance quality such as tetraalkyllead antiknocks including
tetramethyllead, tetraethyllead, physical or redistributed mixtures
of tetramethyllead and tetraethyllead, and the like may be present
therein. The gasoline may also contain antiknock quantities of
other agents such as cyclopentadienyl nickel nitrosyl, N-methyl
aniline, and the like. Antiknock promoters such as tert-butyl
acetate may be included. The gasoline may also contain blending
agents or supplements such as methanol, isopropanol, t-butanol, and
the like. Antioxidants such as 2,6-di-tert-butylphenol,
2,6-di-tert-butyl-p-cresol, phenylenediamines such as
N,N'-di-sec-butyl-p-phenylenediamine, N-isopropylphenylenediamine,
and the like, may be present. Likewise, the gasoline can contain
dyes, metal deactivators, or other types of additives recognized to
serve some useful purpose in improving the gasoline quality.
Cyclopentadienyl manganese tricarbonyls are known antiknocks and
their preparation and use are described in U.S. Pat. Nos.
2,818,417; 2,839,552; and 3,127,351. As important antiknock of this
type is methylcyclopentadienyl manganese tricarbonyl. The amount of
the cyclopentadienyl manganese tricarbonyl added to the gasoline
should be an amount adequate to increase its antiknock
effectiveness. This has generally been found to be in the range of
from about 0.005 to 10 grams per gallon of manganese as a
cyclopentadienyl manganese tricarbonyl. A preferred range is from
about 0.05 to 6 gm (grams) of manganese per gallon as a
cyclopentadienyl manganese tricarbonyl. A more preferred range is
from about 0.05 to about 0.25 grams of manganese per gallon, and a
most preferred range is from about 0.05 to about 0.125 grams of
manganese per gallon as methylcyclopentadienyl manganese
tricarbonyl.
The exhaust gas purification apparatus are well known and generally
employ an oxidation catalytic metal such as platinum, rhodium,
palladium, or iridium or combinations thereof. Some examples of
catalytic converter units are described in U.S. Pat. Nos. 3,441,381
and 3,692,497. The essential elements of such units consist of a
catalytic reactor formed by an enlarged cylindrical-frustoconical
housing having an inlet port and an outlet port. Located within the
housing is a catalyst bed which is a honeycomb
alumina-magnesia-silica monolithic ceramic-supported platinum
catalyst.
In order to obtain rapid warmup required for catalyst activation,
the catalytic reactor is preferably located proximate to the engine
exhaust outlet. By proximate is meant that it is close enough that
the catalyst bed is rapidly heated to "light off" or activation
temperature. The exhaust gas temperature required to accomplish
this is dependent upon the nature of the catalyst. Noble metal
catalysts containing at least some noble metal such as platinum,
palladium or mixtures thereof, activate at lower exhaust
temperatures, e.g., 350.degree.-500.degree. F. However, in order to
ensure activation, the catalytic reactor is preferably located such
that the inlet exhaust temperature is above that 1,000.degree. F.
and more preferably above about 1,400.degree. F. during normal
engine cruise conditions. It is also at temperatures above about
1,400.degree. F. and at concentrations of manganese of and above
0.25 gms per gallon that the cyclopentadienyl manganese antiknocks
are most likely to plug the catalyst and, hence, it is under these
conditions that the present invention is most useful. With
concentrations of manganese of less than 0.25 gms per gallon and at
temperatures under 1,400.degree. F. plugging of the catalyst does
not occur.
In tests run with the aforementioned catalytic converters
containing monolithic ceramic supports it has been found that
plugging occurs by "spikes" forming on the entrance surface of the
cordierite ceramic. These form a network which essentially traps
large manganese particles and caps the entrance to the monolithic
core.
As stated above, the exhaust gas catalyst unit uses a honeycomb,
monolithic ceramic, supported platinum catalyst. These are made by
coating a corrugated ceramic structure with an activated alumina
and a .[.palladium.]. .Iadd.platinum .Iaddend.compound. The
preferred ceramics are made using alumina-silica,
magnesia-alumina-silica (e.g., cordierite) or mixtures thereof.
Palladium can be used in place of platinum, and since these
elements generally occur in nature together, it is sometimes
preferred to use mixtures of platinum and palladium.
The utility of the invention in alleviating plugging with noble
metal catalysts suggests its use with other catalysts if an
undesirable amount of plugging is noted. Many non-noble metals have
been suggested for exhaust gas catalysts. Examples of other
catalytic metals include V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Na, Mo,
Ru, Rh, Ag, W, Re, Os, Ir, Pb, Ba, and the like. These are
generally used in an oxide form. They may be used individually or
in various groupings such as Cu-Cr, Cu-Cr-V, Cu-Pd, Mn-Pd, Ni-Cr
and the like. They may be supported on the above monolithic ceramic
support or on any other of numerous well-known catalyst supports
such as granular, pelletized, or extruded alumina, silica,
silica-alumina, zirconia, magnesia, alumina-magnesia and the
like.
The antiplugging agents of the present invention have the general
formula ##STR1## wherein R is independently selected from hydrogen,
metals, ammonium and substituted ammonium cations, hydrocarbyl
radicals of preferably up to 20 carbon atoms, and substituted
hydrocarbyl radicals. For purposes of this invention a hydrocarbyl
radical can be defined as an organic group solely composed of
hydrogen and carbon atoms. Some non-limiting representative
examples of hydrocarbyl radicals are alkyl, cycloalkyl, alkenyl,
aralkyl, alkaryl, and aryl.
Examples of alkyl groups represented by the R group in the above
general formula are methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl, sec-butyl, tert-butyl, n-amyl, and the various positional
isomers thereof, and likewise the corresponding straight and
branched chain isomers of hexyl, heptyl, octyl, nonyl, decyl,
undecyl, dodecyl, and the like.
When said R groups are cycloalkyl groups, they may be cyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,
cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, and the like.
They may also be such cycloaliphatic groups as
.alpha.-cyclopropyl-ethyl, .alpha.-cyclobutyl-propyl,
.beta.-cyclobutyl-propyl, and similar alkyl derivatives of the
higher cycloalkyls.
The R groups in the above general formula may also be alkenyl
groups such as ethenyl, 1-propenyl, 2-propenyl, isopropenyl,
1-butenyl, 2-butenyl, 3-butenyl, and the corresponding
branched-chain isomers thereof as for example, 1-isobutenyl,
2-isobutenyl, 2-sec-butenyl, including 1-methylene-2-propenyl, and
the various isomers of pentenyl, hexenyl, heptenyl, octenyl,
nonenyl, decenyl, undecenyl, and dodecenyl, including
3,3-dimethyl-1-butenyl, 2,3-dimethyl-1butenyl,
2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl,
1-methyl-1-ethyl-2-propenyl, and the like.
When said R groups are alkaryl groups, they may be tolyl,
2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3,4-xylyl, 3,5-xylyl;
o, m, and p-cumenyl, mesityl, o, m, and p-ethylphenyl,
2-methyl-1-naphthyl, 3-methyl-1-naphthyl, 4-methyl-1-naphthyl,
5-methyl-2-naphthyl, 6-methyl-3-naphthyl, 7-methyl-1-naphthyl,
8-methyl-4-naphthyl, 1-ethyl-2-naphthyl, and its various positional
isomers and the like.
Examples of aryl groups which may be present in the above general
formula are phenyl, naphthyl, and the like.
When said R groups are aralkyl groups, they may be benzyl,
phenylethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenyl-propyl, 1-
and 2-isomers of phenylisopropyl, 1-, 2-, and 3-isomers of
phenylbutyl, and the like.
The substituted hydrocarbyl radicals are hydrocarbyl radicals which
contain substituents such as halogen, hydroxyl, carboxyl,
alkoxycarbonyl, amino, or amide radicals. Thus, the three R groups
may contain the same or different substituents or any one R group
may contain one or more of said radicals substituted thereon.
As mentioned above, the R groups may be halogen substituted. Thus,
chlorine, bromine, iodine, and fluorine may be substituted on the
alkyl, cycloalkyl, alkenyl, alkaryl, aryl, and aralkyl groups which
are present. Non-limiting examples of such substituted groups are
chloromethyl, chloroethyl, bromoethyl, 2-fluoro-1,2-dibromoethyl,
1-iodopropyl, 2-fluoropropyl, 1-chlorobutyl, 2-bromobutyl,
2-iodo-2-methylpropyl, 1-chloropentyl, 3-fluoro-2-methylbutyl,
3-iodo-2-methylbutyl, 1-chloro-2,2-dimethylpropyl, 2-chloroheptyl,
3-fluorononyl, 1-chlorododecyl, and the like. Examples of
halogenated cycloalkyl groups are chlorocyclopropyl,
chlorocyclohexyl, 1,2-dichlorohexyl, bromocyclobutyl,
iodocyclohexyl, and the like.
Examples of halogen-substituted alkenyl groups are bromoethenyl,
chloroethenyl, iodoethenyl, 1-bromododecenyl, and the like.
Examples of halogenated alkaryl groups are chloro-o-tolyl,
chloro-p-tolyl, chloro-m-tolyl, 2-bromo-3,4-xylyl,
4-bromo-2,3-xylyl, 5-bromo-2,4xylyl, 2-bromo-4,5-xylyl, o, m, and
p-tolyl, 3-bromomesityl, chloro(methyl)-1-naphthyl,
iodo(ethyl)-1-naphthyl, all positional isomers of the above, and
the like.
Examples of halogen substituted aryl groups are bromophenyl,
2-bromo-1-naphthyl, 3-bromo-1-naphthyl and all positional isomers
thereof, 2,4-dibromophenyl, 2,3-dibromophenyl, 2,5-dibromophenyl,
2,3,4,5-tetrabromophenyl, 2,3,5,6-tetrabromophenyl,
pentabromophenyl, all isomers of chlorophenyl, and all isomers of
multichlorophenyl: 2-chloro-1-naphthyl and the remaining isomers
thereof: 2,3-dichloro-1-naphthyl, 2,4-dichloro-1-naphthyl and the
remaining positional isomers of
dichloronaphthyl,2,3,4,5-tetrachloro-1-naphthyl.
Amine groups may also be substituted on the R groups. Some
non-limiting illustrative examples of R groups containing amine
substituents are aminomethyl, 2-aminoethyl, 2,2-diaminoethyl,
2-aminoisopropyl, 5-aminopentyl, 1,2-aminododecyl,
1,2-diaminoethyl, 1,5-diaminopentyl, aminocyclobutyl,
aminocyclohexyl, 3-amino-1-propen-1-yl, 5-amino-2-penten-1-yl,
aminophenyl, (methylamino)phenyl, 2-amino-o-tolyl, 4-amino-m-tolyl,
3-amino-p-tolyl, and other positional isomers, various isomers of
diaminophenyl, amino-2,5-xylyl, and various positional isomers
thereof, 2-amino-1-naphthyl, 3-amino-1-naphthyl,
2-amino-3-methyl-1-naphthyl, 2,3-diamino-5-ethyl-1-naphthyl, and
the like.
The R groups may contain amide groups which may be illustrated by
such non-limiting examples as: carbamoylmethyl, 2-carbamoylethyl,
4-carbamoylbutyl, 8-carbamoyl-2-ethyloctyl, 1,4-dicarbamoylbutyl,
carbamoylcyclopentyl, carbamoylcyclohexyl, 2-carbamoyl-o-tolyl,
2-carbamoyl-m-tolyl, 3-carbamoyl-p-tolyl, (carbamoylmethyl)phenyl,
(2-carbamoylethyl)benzyl; o, m, and p-(2-carbamoylethyl)phenyl, and
the like.
The preferred hydrocarbyls are the alkyls, especially the lower
alkyls having from 1 to about 10 carbon atoms, with the more
preferred alkyls being ethyl and methyl. The most preferred alkyl
is ethyl.
The R groups in the above general formula may also be ammonium and
substituted ammonium cations such as morpholinium, alkyl ammonium
and mono-, di-, and trialkanol ammonium. Typical of such materials
are triammonium carboxymethoxysuccinate, the normal
monoethanolamine salt of carboxymethoxysuccinic acid, the normal
diethanolamine salt of carboxymethoxysuccinic acid, the normal
triethanolamine salt of carboxymethoxysuccinic acid, the nornal
tetramethylammonium salt of carboxymethoxysuccinic acid,
tri(ethylammonium)carboxymethoxysuccinate, the normal
monoisopropanolamine salt of carboxymethoxysuccinic acid, the
normal diisopropanolamine salt of carboxymethoxysuccinic acid, the
normal morpholine salt of carboxymethoxysuccinic acid and the
like.
Corresponding esters wherein from 1 to 2 of the ammonium and/or
substituted ammonium cations are replaced with organic groups also
have effective plugging reducing properties when used with a
cyclopentadienyl manganese tricarbonyl containing gasoline. Typical
organic groups include the above hydrocarbyl and substituted
hydrocarbyl groups.
Some examples of metals represented by the R groups are the
monovalent and polyvalent metals, particularly the alkali metals,
and especially sodium, potassium, and lithium. Useful metal salts
are trisodiumcarboxymethoxysuccinate,
tripotassiumcarboxymethoxysuccinate, and
trilithiumcarboxymethoxysuccinate. Additional useful metal salts
are disodiumcarboxymethoxysuccinate,
monosodiumcarboxymethoxysuccinate,
dipotassiumcarboxymethoxysuccinate, monopotassiumcarboxysuccinate,
dilithiumcarboxymethoxysuccinate,
monolithiumcarboxymethoxysuccinate,
monosodiumdipotassiumcarboxymethoxysuccinate,
disodiummonopotassiumcarboxymethoxysuccinate, and the like.
Corresponding esters wherein from 1 to 3 of the metal atoms are
replaced with organic groups are also useful antiplugging agents.
It is understood that in the case of mono esters the remaining two
R groups can both be metal cations, one of the R groups can be a
metal cation and one of the R group can be hydrogen, both of the R
groups can be hydrogen, both of the R groups can be ammonium or
ammonium cations, one of the R groups can be an ammonium or
substituted ammonium cation and the other R group can be hydrogen,
or one of the R groups can be a metal cation and the other R group
can be ammonium or a substituted ammonium cation. In the case of
diesters the remaining R can be either a metal cation, ammonium or
a substituted ammonium cation, or hydrogen. Typical organic groups
are the aforementioned hydrocarbyl and substituted hydrocarbyl
groups. The preferred esters are the mono-, di-, and trialkyl
groups. The more preferred esters are the trialkyl esters of
carboxymethoxysuccinic acid such as the triethyl, tributyl,
trioctyl, tridecyl and tridodecyl esters or mixtures of two or more
such esters, with the most preferred esters being
triethylmethoxysuccinate.
In order to be most advantageously employed as antiplugging agents,
the above compounds should be readily soluble, either directly or
indirectly, in the gasoline. The carboxymethoxysuccinic acid, while
not readily directly soluble in the gasoline is soluble in an
alcohol such as ethyl alcohol and this resulting solution is then
readily soluble in gasoline. The salts of carboxymethoxysuccinic
acid, such as the ammonium salts and the salts of mono- and
polyvalent metals, and particularly the salts of the alkali metals,
especially the mono-, di-, and trilithium salts; the mono-, di-,
and trisodium salts; and the mono-, di-, or tripotassium salts, are
not very readily soluble in gasoline. Thus, some difficulty is
encountered in incorporating these salts in effective quantities
into gasoline to function as antiplugging agents. Other various
aforementioned derivatives of carboxymethoxysuccinic acid are
effective in reducing plugging of the catalyst by various degrees.
The main requirement for these derivatives is that they be directly
or indirectly soluble in the gasoline in useful concentrations.
The salts and esters of carboxymethoxysuccinic acid are known
compounds whose preparation .[.is known.]. .Iadd.has been described
.Iaddend.in the art. The trisodium salt of carboxymethoxysuccinic
acid, or trisodiumcarboxymethoxysuccinate .[.is.]. .Iadd., can be
.Iaddend.prepared as follows:
EXAMPLE 1
Maleic anhydride (0.2 mole; 19.6 g) is dissolved in water (100 ml)
at room temperature and stirred for 10-15 minutes to convert it to
the acid. Glycolic acid (0.24 mole; 18.3 g) is then added and
dissolved with stirring. Calcium hydroxide (Ca 0.36 mole; 27 g)
sufficient to attain a pH of 11.4 as measured initially at
25.degree. C. is next added while stirring the reaction mixture
vigorously. The mixture is heated to reflux and maintained at
reflux for two hours while stirring vigorously. After cooling to
60.degree. C., finely ground sodium carbonate (0.4 mole; 42.4 g) is
added and stirring continued for 15 minutes at 60.degree. C. The
mixture is then cooled to room temperature and the suspended
CaCO.sub.3 filtered off and washed with water. The filtrate
(including the washings) contains the product,
trisodiumcarboxymethoxysuccinate in yields of about 95%.
EXAMPLE 2
The reaction mixture, trisodiumcarboxymethoxysuccinate, of Example
1, is converted to carboxymethoxysuccinic acid by neutralization
with sulfuric acid.
.[.One method of preparing the triethyl ester of
carboxymethoxysuccinic acid is set forth in Example 3 below..].
.[.EXAMPLE 3.].
.[.Ethyl iodoacetate was reacted with L-maleic acid diethylester in
the presence of sodium to give the triethyl ester of
carboxymethoxysuccinic acid; Canadian Journal of Chemistry, pp.
316-317, Vol. 35, 1957..].
.[.Another.]. .Iadd.One .Iaddend.method of preparing
triethylcarboxymethoxysuccinate is according to the equation
##STR2## and is set forth below.
EXAMPLE .[.4.]. .Iadd.3 .Iaddend.
To 700 grams of carboxymethoxysuccinic acid in a reaction flask
.[.were.]. .Iadd.is .Iaddend.added 3,000 grams of
triethylorthoformate. The mixture .[.was.]. .Iadd.is
.Iaddend.stirred and heated to .[.about 40.degree.-50.degree. C.
The.]. .Iadd.distill off .Iaddend.volatiles .[.were distilled off
from the reaction vessel.].. Heating .[.was.]. .Iadd.is
.Iaddend.continued for about 30 hours, at which time no more
volatiles .[.were.]. .Iadd.are .Iaddend.given off. The product,
triethylcarboxymethoxysuccinate, .[.was.]. .Iadd.is
.Iaddend.removed and weighed. .[.The weight of the ester obtained
was 476 grams..].
Tests were run to illustrate the unusual and beneficial effects of
the products of this invention on reducing exhaust catalyst
plugging with manganese. In such tests a single cylinder engine was
used. The A/F mixture was held at approximately 16.0:1 maintaining
1.8% oxygen in the exhaust stream. The engine speed was run
generally with a wide open throttle with the spark firing at an
appropriate crank angle, depending on engine characteristics and
exhaust gas temperature required.
Generally an exhaust gas temperature range of from 1,500.degree. F.
to 1,700.degree. F. in the catalyst entrance cone was
maintained.
The exhaust catalysts used were PTX units manufactured and sold by
Engelhard Industries. The particular PTX unit used was the PTX-3
which is composed of a cordierite ceramic core which has a random
stacked, 16 cell/inch configuration. The ceramic has 0.2 wt.
percent platinum with 0.5 g Pt on the entire ceramic core of the
PTX-3 unit. This ceramic is 2.625 inches in diameter, 3.8 inches
long and is encased in a Monel mesh to take care of thermal
expansion differences between the ceramic and steel housing. This
is encased in a stainless steel housing 3 inches in outer diameter
and 4 inches long. The ceramic is held firmly in place by two
retaining rings on the face of the ceramic welded to the steel
casing; in addition 1/8 inch square strips are welded to the casing
to prevent rotation of the core. The inlet and outlet cover of the
unit are 1.5 inches long and the sides form a 45.degree. angle. The
casings are joined to a pipe which is connected to the exhaust
system. A standard unleaded gasoline of the type described above
was used with from 0.25 to 1.0 g Mn/gal. The concentration of
triethyl ester added to the gasoline ranged from 0.2 g/gal to 1.0
g/gal. To determine when the PTX-3 unit was plugged the back
pressure in the exhaust stream in front of the PTX-3 unit was
measured at predetermined intervals, usually every one or two
hours, as the test progressed. The initial back pressure readings
generally varied from 0.2 to 0.6 psi. When the back pressure
reached a value of 2.0 psi the system was considered plugged and
the test was terminated.
The following results were obtained in the above tests when
triethylcarboxymethoxysuccinate and methylcyclopentadienyl
manganese tricarbonyl were used in the test fuel.
TABLE II ______________________________________ Triethyl ester of
carboxy- methoxysuccinic Temp. Mn conc. acid conc. Hours to plug
______________________________________ 1500.degree. F. 1g/gal 0
46-63 1g/gal 0.2g/gal 193-219 1600.degree. F. 1g/gal 0 30-43 1g/gal
0.2g/gal 38 1g/gal 0.5g/gal 55 1g/gal 1.0g/gal 154 1700.degree. F.
.25g/gal 0 61-95 .25g/gal .25g/gal 159-50 percent plugged
______________________________________
When trimethylcarboxymethoxysuccinate and methylcyclopentadienyl
manganese were used in the test fuel the following results were
obtained.
TABLE III ______________________________________ Trimethyl ester of
carboxy- methoxysuccinic Temp. Mn conc. acid conc.
______________________________________ 1600.degree. F. 1g/gal
1g/gal ______________________________________
The catalyst life (time to plug the catalyst) was extended about 50
percent.
As demonstrated by the data in Tables II and III when the triesters
of carboxymethoxysuccinic acid of the type described above are
blended with gasoline containing cyclopentadienyl manganese
antiknocks unexpected results are obtained in the alleviation of
catalyst plugging.
The amount of antiplugging compound, as for example,
triethylcarboxymethoxysuccinate, sufficient to reduce the plugging
of the catalyst is at least to some extent dependent upon the
amount of manganese present in the gasoline and on the inlet
exhaust temperature. Generally, the greater the concentration of
manganese and the higher the temperature the greater the amount of
antiplugging compound needed to reduce plugging of the catalyst.
Thus, for example, 0.2 gram of triethylcarboxymethoxysuccinate per
gallon of gasoline is sufficient to extend the life of the catalyst
from about 50 hours to about 200 hours at a temperature of
1,500.degree. F. with unleaded gasoline containing 1 gram of
manganese per gallon of gasoline. However, with the same
concentration of manganese, but at a temperature of 1,600.degree.
F., 1 g/gal of triethylcarboxymethoxysuccinate is needed to
effectively reduce plugging of the catalyst.
The lower limit at which the antiplugging compounds of the present
invention, such as the triethyl esters of carboxymethoxysuccinic
acid, are effective to reduce plugging is about 0.01 g/gal.
Preferably, the amount of the compound is greater than 0.03 g/gal,
and more preferably greater than 0.125 g/gal. There is no real
upper limit on the concentration of the antiplugging compound, and,
accordingly, the upper limit is restricted by such secondary
considerations as economics, etc. However, 1.0 g/gal of the
antiplugging compounds, such as the triethyl ester of
carboxymethoxysuccinic acid, is sufficient to reduce plugging of
the catalyst when using a gasoline containing 1 g/gal of manganese
at a temperature of 1,700.degree. F. Thus, since the amount of the
antiplugging compound, such as the aforementioned triethyl ester,
is quite dependent upon the concentration of the manganese, for
practical purposes the upper limit is about 10 g/gal.
It is convenient to utilize additive fluid mixtures composed of
cyclopentadienyl manganese tricarbonyl antiknock agents and
antiplugging agents having the general formula ##STR3## wherein R
is independently selected from hydrogen, metals, ammonium and
substituted ammonium cation, hydrocarbyl radicals, and substituted
hydrocarbyl radicals. These additive fluid mixtures are added to
lowlead or unleaded gasoline. In other words, part of the present
invention are antiknock-antiplug fluids which comprise
cyclopentadienyl manganese tricarbonyl antiknock agents and the
antiplugging agents of the type described hereinabove.
Use of such antiknock-antiplug fluid in addition to resulting in
great convenience in storage, handling, transportation, blending
with fuels, and so forth, also are potent concentrates which serve
the multipurpose functions of being useful as antiknocks, and
catalyst plugging reducers.
In these fluid compositions the weight ratio of
manganese-to-antiplugging agent can vary from about 0.03 gram of
antiplugging agent such as triethylcarboxymethoxysuccinate to 1
gram of manganese or even 0.01 gram of the antiplugging agent such
as triethylcarboxymethoxysuccinate to 1 gram of manganese on the
one hand to about 10 grams of the antiplugging agent such as
triethylcarboxymethoxysuccinate to about 1 gram of manganese on the
other hand. Some examples of preferred fluids are 0.03 grams of
triethylcarboxymethoxysuccinate to 0.125 grams of manganese, 0.06
grams of triethylcarboxymethoxysuccinate to 0.125 gram of
manganese, 0.2 gram of triethylcarboxymethoxysuccinate to 1 gram of
manganese, 0.1 gram of triethylcarboxymethoxysuccinate to 0.25 gram
of manganese, 0.5 gram of triethylcarboxymethoxysuccinate to 1 gram
of manganese, 1 gram of triethylcarboxymethoxysuccinate to 1 gram
of manganese, 1 gram of trimethylcarboxymethoxysuccinate to 1 gram
of manganese, and 2 grams of triethylcarboxymethoxysuccinate to 1
gram of manganese. The fluids may optionally contain other
additives such as antioxidants, antirust agents, detergents, etc.,
as well as solvents, e.g., a hydrocarbon, to facilitate
handling.
Although the preferred antiplugging compounds have the general
formula ##STR4## wherein R has been previously described, it is
believed that compounds having the skeletal structure ##STR5## will
have useful properties in reducing the plugging of exhaust
catalysts.
Thus for example, one, some, or all of the carbon hydrogens can be
replaced by other groups such as alkyls, cycloalkyls, aryls,
aralkyls, and alkaryls. Furthermore, said carbon hydrogens may be
substituted by halogen, hydroxyl, carboxyl, and amino radicals. A
limiting factor regarding the numbers and types of group that can
replace the carbon hydrogens is that these groups do not make the
compound insoluble in gasoline to such a degree that an effective
amount of compound cannot be added.
Although the compounds of the present invention have the most
utility when added to gasoline, they can also be used in
conjunction with other liquid petroleum distillate fuels such as
kerosene, diesel fuel, jet engine fuel, and the like.
Claims to the invention follow.
* * * * *