CA1058870A - Fuel compositions and additive mixtures for alleviation of exhaust gas catalyst plugging - Google Patents

Abstract

Abstract of the Disclosure 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 cyclo-pentasienyl manganese antiknock.

Description

Cyclopentadienyl manganese compounds are excellent antiknocks in gasoline used to operate internal com-bustion engines. These manganese compounds have prov~d to be especially beneficial in solving some of the problems present when low-lead or lead-free gasolines are used with internal com-bustion engines. Use of such compounds as antiknocks is described in U.S. 2,818,417; U.S. 2,839,552; and U.S. 3,127,351. 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 tncrea~e ln e~hau~t backpressure and a decrea~e in the effective life of sald catalysts. m e present invent~on provlde~ a simple e~fectlve means of alleviating this problem.
It has been previously ~ugge~ted that the additlon Or trlethyl citrate to gasoline mlxes containing organomanganese antlknocks tends to reduce cataly~t plugging. m e u~e of trlethyl citrate, however, has proved to be of rather llmited success ln reducing the plugglng problem, especially at higher temperatures.

Summary According to the present inventlon~ the useful life of an exhaust ga3 cataly~t ln an exhaust ~ystem of an engine operating on gasollne containing ~ cyclopentadienyl manganese ~ntlknock iB greatly lncreased by providlng new additlve fluld~
and g~ollne compositlons which contaln an amount of carboxy-methoxysucclnlc acld or gasoline 801uble derlvatlve thereof 6ufflclent to allevlate plugging of the exhaust gas cataly~t.

Descrl~tion o~ the Preferred Embodiments me essence of the pre~ent inve~tion resides in reducing the plugging o~ oxidation metal catalytic apparatus for purlfying exhaust gases of internal combustlon englnes whlch burn a gasoline contalning an organ~manganese compound.
Thls reduction in plugglng 1~ effected by the addltion of ~arboxymethoxysuccinlc acld, its gasoline ~oluble esters.
salt~, or other ga~oline soluble derivatlves to the gasollne.
Aceordingly, a preferred embodiment i~ a gasollne sultable ~or u~e ln an internal combustion engine a~d containlng an 105~870 amount of organomanganese compound, pre~erably a cyclopentadlenyl manganese tricarbonyl, su~lclent to lncrease it~ antiknock effectiveness, and al~o contalnlng an amount ~u~ficlent to prevent plugging o~ the catalyst of carboxymethoxysuccinl~
~cid, or lts gasoline soluble saltsJ esters, snd other gasollne soluble derl~atlves.
A flurther embodiment o~ the pre~ent invention iB
a gasollne addltive ~luid composltlon ~omprising an organo-mangane~e compound, prerersbly a cyclopentadienyl manganese tricarbonyl, and mo~t preferably methylcyclopentadienyl manganese trlcarbonyl, ln nn amount s~fflclent to ~mprove the antiknock characterlstlcs o~ the ~asollne and carboxymethoxy-succinlc acld, or lts gasollne 601uble salt~, e~ters, and other ga~oline ~oluble derivatives, preferably the mono-, dl-, and trlesters Or carboxymethoxysucclnlc acld, ~nd most preferably the trlesters Or carboxymethoxysucclnlc acld, ln an amolmt surflclent to reduce catalyst plugging.
Since the lnvention al80 embodies the operation of an ~nternal combustion engine ln a manner whlch results ln reduced plugging Or the catalyst, a still further embodlment 1~ a method of operating an internal combustlon englne u8ing a ~asollne containlng an organomanganese, pre~erably a cyclo-pentadlenyl manganese trlcarbonyl, and mo~t preferably methyl-cyclopentadienyl mangane~e trlcarbonyl antiknock ln a manner whlch result~ in substantlal reductlon in the plugglng o~ the cataly~t, sald method compri~ing (a) supplying to the fuel ~nductlon system o~ said engine a gasoline contaln~ng an organomanganese antlknock and a gasoline æoluble solutlon of carboxymethoxysuccinic acld, its ~alts, esters, or other gasol$ne soluble derivatives, (b) mixing said ga~oline with air, (c) inducting the mixture lnto the combustion chambers of said englne, (d) compressing said mlxture, (e) ignitlng sald compressed mixture, and ~f) exhaustlng the resultant combustlon products which have a reduced plugging effect on the catalyst through ~aid cataly~t.
Llquid hydrocarbon fuels of the gasoline boillng range are mixtures of hydrocarbons havlng a boiling ra~ge of from about 80F. to about 430F. 0~ course, these mixtures can contain indlvidual con~tituents bolllng abo~e or below these flgures. m ese hydrocarbon mixtures contain aromatlc hgdrocarbon6, saturated hydrocarbons and olefinlc hydrocarbons.
The bulk of the hydrocarbon mlxture 18 obtained by reflning crude petroleum by either straight dlstillatlon or through the use Or one o~ the many known reflnlng processes, such a8 thermal cracklng, catalytlc cracklng, catalytlc hydroforming, catAlytlc reformlng, and the llke. Generally, the final g~oline ls ~ blend o~ 9toc~8 obtalned from several refinery proce~ses. The final blend may also contain hydrocarbons made by other procedures BUCh as alkylate made by the reaction of C~ olefins and butane~ using an acld catalyst such as sulfuric acid or hydrofluorie acid.
Pre~erred gasoline~ are those havlng a Re~earch Octane Number of at least 85. A more preferred Research Octane ~umber 18 90 or greater. It 1~ also preferred to blend the ga~ollne such that it has a content of aromatlc hydrocarbons ranglng from 10 to ab~ut 60 volume percent~ an oleflnlc hydrocarbon content ranging from O to about 30 volume percent, and a saturate hydrocarbon content ranging from~about 40 to 80 volume percent, b~sed on the whole gasoline.

In order to obtaln fuels ha~lng properties required by modern automotlve englne~, a blending procedure i8 generally ~ollowed by selecting appropriate blendlng stock~ and blending them ln ~ultable proportions. The required octane lev~l i6 most readlly accompll~hed by employing aromatlcs (e.~., BTX, catalytic reformate or the like), alkylate (e.g., C~_~ saturates made by reacting C~ ole~lns wlth l~obutane uslng a HF or H2S0 cataly~t), or b~ends of dl~erent type~.
The balance o~ the whole ~uel may be made up oi other components such as other saturate~, olefin3, or the llke.
The oleflns are generally ~ormed by us~ng such procedure~ as thermal cracking, catalytlc crac~ing and polymerlzation.
Dehydrogenation o~ parafflns to olefins can ~upplement the ga~eou~ olefins occurrlng ln the reflnery to produce feed materlal for elther polymerlzatlon or alXylation processes.
The saturated ga~oline component~ comprise paraffin~ and naphthenes. me~e saturates are obtained from (1) virgin ~asollne by dlstillatlon (stralght run gasoline), (2) alkylatlon processes (alkylates) and (~ omerizatlon procedures (converslon o~ normal parafflns to branched chain paraf~lns Or greater octane quallty). Saturated ga~ollne components also occur ~n so-called natural gasolines. In addltion to the fore-going, thermally cracked stocks, catalytlcally cracked ~tocks and catalytic reformate~ contaln saturated components.
The classlflcatlon o~ gasollne components lnto QromQtics, ole~ins and saturates 18 well recognlzed in the art.
Procedures for analyzlng ga~olines and gasoline components for hydrocarbvn cQ~positlon have long been known and used. Commonly u~ed today 1~ the FIA anslytlcal method lnvolving fluorescent ~058870 indlcator adsorption technlque~. These ~re based on ~electlve adsorptlon of gasollne components on an activated silica gel column, the component~ belng concentrated by hydrocarbon type ln different parts Or the column. Special ~luorescent dyes are added to the test sample and are al~o selectively ~eparated with the sample fractions to make the bGundarie~ of the aromatlcs, olerlns and ~aturates clearly vi~ible under ultravlolet light.
Further detail~ concern$ng this method can be found ln ~1969 Boo~ Or ASTM Standards, n January 1969 Editlon, under ASTM
Te~t Deslgnation ~ 1319-66T.
m e motor gasolines used in formulating the improved ~uels o~ thl~ invention generally have inltial boiling points ranglng from about 80 to about 105F. and final ~olling points ranglng from about 380 to about 430F. as measured by the ~tandard ASTM dlst~llatlon procedure (ASTM D-8~). Intermedlate gasoline fraction~ boll away at temperaturec wlthin the~e extreme~.
From the standpoint Or minimizing atmospherlc pollution to the greatest extent po~sible, lt i~ best to keep the ole~ln content of the fuel a8 low as can be economlcally achieved a6 oleflns reportedly give rise to ~mog-forming emi~ions, e~pecially from ~mproperly ad~usted vehlcular en$ines.
Accordlngly, ln the preferred base stocks of this inventlon the ole~n content wlll not exceed about 10 volume percent and the most partlcularly preferred ruels wlll not contain more than about 5 percent ole~lns. Table I lllustrates the hydrocarbon type makeup o~ a number o~ particulàrly prererred ruels rOr u~e ln this in~ention.

TABLE I
HYdrocarbon Blend~ of Particularly Preferred Base Fuels Volume Percentage Fuel Aromatice Olefins Saturate~
.
A ~5.0 2.0 6~.o 40.0 1.5 58.5 20.0 2.5 77.5 D - ~3.5 1.0 65.5 E 36.5 2.5 61.0 ~0 F 43.5 1.5 55.0 G 49.5 2.5 48.o It ls also desirable to utlllze base ~uels having a low iulfur content as the oxides of sulfur tend to contrlbute an lrritating and choking character to smog and other forms o~
atmospheric pollutlon. ThereforeJ to the extent it i8 economlcally feaslble, the fuel will contain not more than about 0.1 weight percènt Or sulfur in the form of conventional ~ulfur-contalning impur~tles. Fuels ln whlch the sulfur content 1~ no more than about 0.02 welght percent are ~speclally pre~erred ~or use ln thls lnventlon.
Normally the gasollne to which thls lnventlon ls applièd i8 lead-free or sub~tantlally lead-free, although ?mall amounts o~ organolead addltlve~ usually employed to give ~uel6 of impro~ed performance quallty such as tetraalkyllead antiknocks lncluding tetramethyllead, tetraethyllead, p~ysical or redlstributed mlxture~ of tetramethyllead and tetraethyllead, and the like may be present therein. m e ga~oline may also contaln antl~nock quantlties of other agent~ such as cyclopentadienyl nlckel nitrosyl, N-methyl anlllne, and the like. Rntikr.oc'.c promoters such as tert-butyl acetate may be ~ncluded. The gas~line may al80 contaln blen~lng agents or 6upplements such -7- ?

a~ methanol, lsopropanol, t-butanol, and the like. Antioxldant8 6uch as 2,6-dl-tert-butylphenol, 2,6-di-tert-butyl-~-cresol, phenglenediamines such as N,N'-dl-sec-butyl-~-phenylenediamine, N-lsopropylphenylenedlamine, and the llke, may be pre~ent.
Ll~ewl6e, the gasoline can contaln dye~, metal deactlvators, or other type~ Or addltlves recognized to serve some useful purpose ln improvine the gasoline quality.
Cyclopentadlenyl manganese trlcarbonyls are hnown ~ntlknocks and their preparation and use are described ln U.S. 2,818,417; U.S. 2,839,552; and U.S. 3,127,351. An i'mportant antiknock of thi~ type 1B methylcyclopentadlenyl manganese tricarbonyl. The ~mount of the cyclopentadienyl m~nganese tricarbonyl added to the gasollne should be an amount adequate to lncrease its antlknock effectiveness. Thls ha~
generally been found to be ln the range of from about 0.005 to 10 grams per gallon of manganese a~ a cyclopentadlenyl manganese tricarbonyl. A preferred range 18 from about 0,05 to 6 gm (grams) of manganese per gallon as a cyclopentadienyl manganese tricarbonyl. A more preferred range i8 from about 0.05 to about 0.25 grams of mangane~e per gallon, and a most pre~erred range is from about 0.05 to about 0.125 gram~ of manganese per gallon as methylcyclopentadienyl manganese tricarbonyl.
me exhaust gas purl~ication apparatu~ are well known and generally employ an oxidatlon catalytic metal such as platinum, rhodium, palladlum, or iridlum or combinations thereof. Some examples of catalytlc converter units are described in U.S. 3,441J381 and U.S. 3,692,497. m e es~ential-elements of such unlts consist of a catalytic reactor formed by an enlarged cylindrical-fru6toconical nouslng having an lnlet port and an outlet port. Located wlthin the housing 10~;8870 i8 ~ cataly~t bed which ls a honeycomb alumina-magnesia-s~lica monolithic ceramic-su~ported platlnum cataly~t.
In order to obtaln rapid warmup required for cataly~t actlvation, the catalytic reactor is prefer~bly located proximate to the engine exhaust outlet. By proximate i~ meant that it 1~ close en~ugh that the cataly~t bed 18 rapidly heated to "llght off" or actlYation temperature. m e exhaust gas temperature required to accomplish this iE dependent upon the nature of the catalyst. Noble metal catalyst~ containlng at least ~ome noble metal such as platinum, palladium or mixture~ thereof, actlvate at lower exhau~t temperature~, e.g., ~50-500F. However, in order to en~ure activatlonJ
t~e catalytic reactor 1~ preferably located such that the inlet exhaust temperature is above about 1,000~. and ~ore preferably above about 1,400F. durlng normal engine cruise conditions.
It 18 al~o ~t temperatures a~ove about 1,400F. and at concentrations of manganese of and above 0.25 gm~ per gallon that the cyclopentadlenyl manganese antiknock~ ~re most likely to plug the catalyst and, hence, it 1~ under the~e conditlon~
that the pre3ent lnYention i~ most u~eful. With concentratlons of manganese o~ le~s than 0.25 gm8 per gallon and at temperatures under 1,400~. plugging of the cataly6t does not occur.
~n tects run with the aforementloned catalytic con~erter~ contain~ng monollthlc cera~lc ~upport~ ~t ha~ been f~und that plugglng occurs by "spikes" forming on the entrance surrace o~ the cord~erite ceramic. These form a network whlch e~sentially trap~ large mangane~e partlcles and caps the entrance to the monolith~c core.

AB ~tated above, the exhaust gas catalyst unit u~es a honeycomb, monollth~c ceramic, supported platinum catnlyst.
m e~e are made by coat~ng a corrugated cera~ic structure with an activated alumina and a palladium compound. The preferred ceramics are made uslng alumina-sillca, magnesla-alum~na-sillca (e.~, cordierite) or mixtures thereof. Palladium can be used in place of platinum, and since the~e elements generally occur ~n nature together, lt 1~ sometimes preferred to use mixtures of platinum and palladium.
The utlllty of the inventlon in alleviQtlng plugging wlth noble metal catalystæ suggests it~ use w~th other catalyst~
if an unde61rable amount Or plu~ging 18 noted. Many non-noble metals have been suggested for exhaust gas catalysts. Examples o~ other catalytlc metal~ lnclude ~, Cr, Mh, Fe, Co, N1, Cu, ~n, ~r. N~, Mo, Ru, Rh, A~, W, Re, 08, IrJ Pb, ~a, and the li~e.
These are ~enerally u~ed in an oxlde form. They may be used indiv1dually or ln varlous grouplng8 ~uch as Cu-Cr, Cu-Cr-V, Cu-~d, Mn-Pd~ Ni-Cr and the like. They may be supported ~n the above monolithlc ceramic support or on any other of numerous well-known catalyst supports ~uch as granu~ar, pelletlzed, or extruded alumina, sllica, slllca alumina, zlrconia, magnesia, alum~na-magne~ia and the llke.
The antlplug~lng ngents of the pre~ent lnventlon have t~e general formula H
ROOC-C-H H ., ROOC-C - O C-COOR
. ~ H
wherein R ie lndependently ~elected from hydrogen, metal~.

, , ammonlum and ~ubstltuted ammonium cations, hydrocarbyl radicals of preferably up ~o 20 carbon atom~, ~nd substltuted hydrocarbyl radlcals. For purposes of this ln~entlon a hyd~ocarbyl radlcal cnn be defined as an organic group ~olely composed o~ hydrogen and carbon atom~. Some non-limiting repre~entatlve examples of hydrocarbyl radlcals are alkyl, cycloalkyl, alkenyl, aralkyl, alkaryl, and aryl.
Examples. of alkyl groups represented by the R group ln the above general ~ormula are methyl, ethyl~ n-propyl, isopropyl, n-butyl, i~obutyl, ~ec-butyl, tert-butyl, n-amyl, and the varlous pos1tional isomers thereof, and l~kewi~ the corresponding stral~ht and branched chaln l~omers ~f hexyl, heptyl. octyl, nonyl, decyl, undecyl, dodecyl, and the llke.
When said R groups are cycloalkyl gr~ups, they may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, and the llke. They may al~o be ~uch cycloaliphatic groups as a-cyclopropyl-ethyl, a-cyclobutyl-propyl, ~-cyclobutyl-propyl, and similar alkyl derivatives o~ the higher cycloalkyls.
The R groups in the above general formula may alEo be alkenyl groups such as ethenyl, l-propenyl, 2-~ropenyl, l~opropenyl, l-butenyl, 2-butenyl, 3-butenyl, and the corresponding br~nched-chain isomerQ thereof a~ for example, . l-isobutenyl, 2-i~obutenyl, 2-sec-butenyl, lncludlng 1-methylene-2-propenyl, and the varlow ls~mer~ vr pentenyl, hexenyl, hepteng~, octenyl, nonenyl, decenylJ undecenyl, and dodecenyl, including ~,3-dimethyl-1-butenyl, 2,3-dimethyl-1-butenyl, 2,~-dlmethyl-2-butenyl, Z,3-d~methyl-~-butenyl, l-methyl-l-ethy1-2-propenyl. and the like.

105~870 When said R groups are alkaryl group~, they may be tolyl,

2,~-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, ~,4-xylyl, ~,5-xylyl;
o, m, and ~-cumenyl, mesityl, o, m, and ~-ethylphenyl, 2-methyl-l-naphthyl, ~-methyl-l-naphthyl, 4-methyl-l-naphthyl, 5-methyl-2-naphthyl, 6-methyl-3-naphthyl, 7-methyl-l-naphthyl, 8-methyl-4-naphthyl, 1-ethyl-2-naphthyl, and itæ various positional l~omer~ and the like.
Examples of aryl group~ which may be present ln the above ~eneral formulaare phenyl, naphthylJ and the like.
When said R group~ ~re aralkyl groups, they may be benzyl, phe~ylethyl, l-phenylpropyl, 2-phenylpropyl, ~-phenyl-propyl, 1- and 2-lsomers of phenyllsopropyl, 1-, 2-, and 3-lsomers of phenylbutyl, and the llke.
The ~ub~tituted hydrocarbyl radlcal~ are hydrocarbyl radicals whlch contain sub~tituents such a~ halogen, hydroxyl, carboxyl, alkoxycarbonyl, amlno, or amide radical~. Thus, the three R groups may conta$n the same or different sub~tituents or any one R group may contaln one or more of ~aid radlcals ~ubstituted thereon.
As mentioned above, t~e R groups may be halogen substltuted. Thus, ~hlorine, bromine, iodine, and fluorine m~y be 6ubstituted on the alkyl, cycloalkyl, alkenyl, alkaryl, aryl, and aralkyl groups which are present. Non-limiting examples of such ~ubstituted groups are chloromethyl, Chloroethyl, bromoethyl~ 2-fluoro-1,2-d$bromoethyl, l-lodopropyl, 2-fluoro-propyl, l-chlorobutyl, 2-bromobutyl, 2-iodo-2-methylpropyl, l-chloropentyl, 3-fluoro-2-methylbutyl, 3-iodo-2-methylbutyl, l-chloro-2,2-d$methylpropyl, 2-chloroheptyl, 3-fluorononyl, l-chlorododecyl, and the like. Examples of halogenated r cycloalkgl group~ are chlorocyclopropyl, chlorocyclohexyl, 1,2-dichlorohexyl, bromocyclobutyl, lodocycl~hexyl, and the like.
Examples of halogen-6ub~titu~ed alkenyl groups are bromoethenyl, chloroethenyl, iodoethenyl, l-bromododecenyl, and the li~e.
Exa~ples o~ halogenated alkaryl group~ are chloro-o-tolyl, chloro-~-tolyl, chloro-m-tolyl, 2-bromo-3,4-xylyl, : 4-bromo-2~-xylyl, 5-bromo-2,4-xylyl, 2-bromo-4,5-xylyl, o, m, Qna ~-tolyl, 3-bromome~ltyl, chloro(methyl)-l-naphthyl, iodo(ethyl)-l-naphthyl, all positional isomeræ of the above, and t~e like.
Ex~mples o~ halogen ~ub~tltuted aryl groups are bromophenyl, 2~bromo-1-naphthyl, ~-bromo-l-naphthyl and all po~itional l~omer~ thereo~J 2,4-dibromophenyl, 2,~-dibromophenyl, 2.5-dibr~mophenyl, 2 J 3.4,5-tetrabramophenyl, 2,~,~,6-tetra-bromophenyl, pentabromophengl, all l~omers of chlorophenyl, ~nd all lGomers o~ ~ultlchlorophengl: 2-chloro-1-naphthyl and the remaining i60mers thereof: 2,3-dichloro-1-nap~thyl, 2,4-dichloro-l-naphthyl and the rema~ning po~itlonal ia~mers of dichloronaphthyl, 2,~,4,5-tetrachloro-1-naphthyl.
Amine grOUp8 may al~o be substltuted on the R groups.
~ome non-limiting illustrative example~ of R groups containing amine sub~tituents are aminomethyl, 2-aminoethyl, 2,2-diamino-ethyl, ~-aminoisopropyl, 5-amlnopentyl, ~2-a~inododecyl.
1~2-di~mlnoethyl, 1,5-dlamlnopentyl, aminocyclobutyl, am~no-cyclohexyl, 3-amino-1-propen-1-yl, 5-amino-2-penten-1-yl, aminophenyl~ ~methylam~no)phenyl, 2-amino-o-tolyl, 4-~mino-m-~01Y1J 3-~mino-~-tolyl, and other positional lsomers, varlous ~somers of diamlnophenyl, amlno-2,5-.xylyl, ~nd variou~

positlonal ~ ~omers thereo~, 2-amino-1-naphthyl, 3-amlno-1-naphthyl, 2-amino-3-methyl-1-naphthyl, 2,~-dla~ino-5-ethyl-l-naphthyl, and the 1~ ke.
m e R group~ may contaln a~ide groups whlch may be lllustrated by such n~n-llmiting example~ a~: carbamoylmethyl, 2-carbamoylethyl, 4-carbamoylbutyl, 8-carbamoyl-2-ethyloctyl, 1,4-dicarbamoylbutyl, carbamoylcyclopentyl. carbamoylcyclohexyl, 2-carbamoyl-o-tolyl, 2-carbamoyl-m-tolyl, 3-carbamoyl-~-tolyl, tcarbamoylmethyl)phenyl, (2-carbamoylethyl)benzyl; o, m, and ~-(2-carbamoylethyl)phenyl, ~nd the like, me pre~erred hydrocarbyls are the alkyl~, especlally the lower al~yls having from 1 to about 10 carbon atoms, wlth the more preferred alkyls belng ethyl and methyl. The mo~t preîerred alkyl 1~ ethyl~
q~he ~ groups in the above general formula may also be ammonlum and ~ubstltuted ammonium catlon~ ~uch as morpholinium~
alkyl ammonium and mono-, dl-, and trialkRnol ammonium. Typlcal of ~uch material~ ~re triammonium carboxymethoxysuccinate, the normal monoethanolamine ~alt of carboxymethoxysuccinlc acld, the normal diethanolamlne salt Or carboxymethoxysuccinic acld, the normal triethanolamine salt of carboxymethoxy~uccinic acld, : the normal tetramethylammonium ~alt of carboxymethoxysucc~nic acld, trl(ethylammonium)carboxymethoxysuccinate, the normal monolsopropanolamlne salt Or carboxymethoxysucclnlc acld, the normal dllsopropanolamlne ~alt o~ carboxymethoxysuccinic acld, the n~rmal morpholine salt Or carboxymethoxysuccinic acid ~nd the llke.
Corresponding esters wherein ~rom 1 to 2 o~ the ammonlum andtor ~ub~tituted ammonium cation~ are replaced With organlc group~ al~o have effectlve plugging reduclng propertieQ when use~ with a cyclopentadienyl mangane~e tri-carbonyl containing gasoline. Typical organic groups include the above hydrocarbyl and substituted hydrocarbyl groups.
- 5 Some ex~mple~ of metals represented by the R group~
~re the monovalent and polyvalent metals, partlcularly the alkali metals, and especlally sodium, potas~lum, and lithlum.
Useful metal ~alts are trisodiumcarboxymethoxysucc~nate, tripotas~lumcarboxymethoxysucclnate, and trilithiumcarboxy-methoxysuccinate. Addltlonal use~ul metal ~alts are dlsodium-carboxymethoxy~uccinate, monosodiumcarboxymethoxysuccinate, dipotasslumcarboxymethoxysucclnate, ~onopot~ssiumcarboxymethoxy-~uccinate) dilithiumcarboxymethoxy6uccinate, monollthiumcarboxy-methoxysuccinate, monosodiumdlpota~slumcarboxymethoxysuccinate, dlsodiummonopotasslumcarboxymcthoxysucclnate, and the like.
Corre~ponding ester~ whereln from 1 to 3 of the met~l atoms are replaced with organlc groups are al80 useflul an~iplugging agents~ It is under~tood that in the case of mono ester~ the remalning two R groups can both be metal cat1on~ ~
one o~ the R group~ can be a metal catlon and one o~ the R
group can be hydrogen. bo~h of the R groups can be hydrogen, both o~ the R groups can be ammonium or ammonlum catlons, one o~ the R groups can be an ammonium or sub~tituted ammonlum catlon and t~e other R grcup can be hydrogen, or one of the R groups can be a me~l cation and the other R group c~n be .~mmonlum or a substituted ammonlum catlon. In the ca~e Or d~e~ters the remalning R can be elther a metal cation, ammonlum or a ~ubstltuted ammonium catlon~-or hydroeen. Typlcal or~anic groups are the a~orementioned hydrocarbyl and ~ubstituted - . .

~ydrocarbyl groups. The pre~erred e~ters are the mono-, di-, and trlalkyl esters. me more preferred e8ters are the tri~lkyl e8ter8 of carboxymethoxysuccinlc ~cid ~uch ~8 the trlethyl.
t~ibutyl, trloctyl~ trldeeyl a~nd trldodecyl esters or mlxtures o~ two or ~ore uch e~ter~, wlth the most preferred esters belng trlethyl~ethoxysuccinate.
In order to ~e mo~t advantageously e~ployed as antlplugging agents~ the a~ove comp~unds should be readily soluble, either ~lrectly or lndirectly, ln the ga~oline.
The carboxymethoxysuccinic 2~c~d, wh$1e not readily clirectly 801uble in the gasollne i8 soluble in ~n alcohol such ~8 ethyl alcohol and thls resulting ~olut~on is then readily soluble in gasoline. The salts of car~oxymethoxy~uccinic acid, such a~ the ammonlum salt~ and the salts of mono- and polyvalent metals, and p~rtlcularly the sa}ts of the alk~li met~ls, especially the mono-, di-. ~nd trlllth~um salt~; the mono-, dl- and tri~odlum 8alt8; and the mono-, dl-) or trlpotassium ~alt~, are not ve~y readily ~oluble in ga3011ne.
mu~ some dif~lculty iB enc~untered ln incorporatlng these 8alt8 in effectl~e auantltle~ into ga~oline to runction ~
antlplugglng agents. Other various aforementioned deri~atives o~ carboxymethoxysuccinic acid are ef~ectl~e ln reduclng plugeing of the cataly~t by varlou~ degrees. The main requlrement ~or these ~criYativex i8 that they be directly or lndirectly soluble in the g~sollne in usenul concentratiQns.
me 8alts and e~ters of carboxymethoxysuccinlc acid are known coMpounds who~e preparat$on $~ known in the art.
The trlsodium ~lt of carboxyl~ethoxy~ucclnic ac~d, or trisodlumcarboxymethoxy~uccln~te ~8 prepared as ~ollows:

105~3870 Exam~le 1 ~
, Maleic anhydride (.2 mole; 19.6 g) 18 dissol~ed in water (100 ml) at room temperature and stirred ~or 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 hydroxi~e (Ca o.36 mole; 27 g) suf~icient to attain a pH of 11.4 as measured init1ally at 25C. is next added while stirring the reaction mixture vigorously. The mixture is heated to re~lux and maintained at re~lux ~or two hours while stirring vigorously. After cooling to 60C., flnely ground sodium carbonate (0.4 mole; 42.4 g) i8 added and stirring continued for 15 minutes at 60C. The mixture i5 then cooled to room temperature and the suspended CaC03 filtered o~ and washed with water. The flltrate (including the washings) contains the product. trisodiumcarboxymethoxysuccinate in yields of about 95/0.
Examle 2 The reaction mixture, trisodlumcarboxymethoxysuccinate, Or Example 1, is converte~ to carboxymethoxysuccinic acid by neutrallzation with sul~uric acld.
One method of preparing the triethyl ester o~ carboxy-methoxysuccinic acid i8 set ~orth in Example 3 below.
ExamPle 3 Ethyl iodoacetate was reacted with L-maleic acid diethylester in the presence o~ sodium to give the triethyl ester o~ carboxymethoxysuccinic acid; Canadian Journal of Chemistry, pp. 316-317, Vol. 35, 1957;

10~8~70 Another method o~ preparlng triethylca;-boxymethoxy-~uccinate 1B accordlng to the equatlon CH2-COOH OEt Hl~-COOH ~ 3 HC / OEt OEt EtOOC-C-H H
EtOOC-? O ~ COOEt+3EtOH +3HCOOEt H H
and i8 set forth below.
Example 4 To 700 grams of carboxymethoxysucclnic acid in a reactlon ~lask were added 3,000 grams of triethylortho~ormate.
The mlxture wa~ stlrred and heated to about 40-50C. m e volatlles were dlstllled off from the reaction ve~sel. Heating was continued for about 30 hour~, at whlch tlme no more volatiles were glven off. The product, trlethylcarboxymethoxysucclnate, was removed and welghed. The weight of the ester obtained was 476 grams.
Te~ts were run to illu~trate the unusual and beneflclal effects of the products of this invention on reducing exhaust catalyst plugging with manganese. In such tests a single cyllnder engine wa~ used. The A/F mixture was held at approximately 16.0:1 maintaining 1.8/o oxygen ln the exhaust stream. The engine speed WRB run generally wlth a wlde open throttle with the spark firlng at an appropriate crank angle, depending on engine characteristlcs and exhaust ga~ temperature requlred, il~

1058~370 Generally an exhau~t ga~ temperature range o~ ~rom 1,500F. to 1,700~. in the cataly~t entrance cone wa6 mainta~ned.
The ex~aust catalysts used were PTX units manufactured and sold by EhgeIhard In~ustrie~. The particular PTX unlt used was the PTX-3 which i8 compo~ed o~ a cordierite ceramic core wh~ch has a random ~tacked, 16 cell/inch conflguration.
The ceramic h~s 0.c wt. percent platinum with 0.5 g Pt on the entire ceramic core o~ the PTX-3 unit. Thl~ ceramic is 2.625' ln diame~er, 3.8~' long ~nd i~ encased ln a Monel mesh to take care o~ thermal exp~n~ion dlfferences between the ceramlc and steel housing. Thls ls encased ln a stalnle~s steel housing

3 n in outer d1ameter ~nd 4" long. me ceramic ls held firmly $n place by two retaining rings on the face of the ceramic welded t~ the steel casin~ ln addltlon 1/8" s~,uare strips are welded to the caslng to prevent rotatlon of the core.
The inlet and outlet cover of the unit are 1.5" long and the ~ldes form a 45 an~le. The caslngs are Jolnedto a pipe which 18 connected to the exhaust system. A standard unleaded ga~ollne o~ the type descrlbed above was used with from 0.25 to 1.0 g Mn~eal. The concentration of trieth~l ester added to the gasoline r3nged ~rom 0.2 g/gal to 1.0 g/gal. To determ1ne when the PTX-3 unlt W~8 plugged the back pressure ln the exhaust stream ln ~ront o~ the PTX-3 unlt was mea~ured ~C predete~ined interval6, usually every one or two hours, as the test progressed. The $n$tial back pressure readings generally varied ~rom 0.2 to o.6 p8i. When the back pressure rea~hed a value of ~.0 p~i the system was considered plugged and the test wa~ termlnated.

lOS8870 The following r~8ult8 were obtalned in the a~ove test~ when triethylcarboh~methoxysucclnate and methylcyclopenta-dienyl manganese trlcarbonyl were u~ed in the test fuel.
TABLE II
Trlethyl ester of carboxy-methoxysuccinic TemP. Mh conc. acid conc.Hours to Plug 1500F. lg/gal 0 ~6 - 6~
lgtgal 0.2g/gal 197 - 219 1600F. lg/gal 0 30 - 4 lg/gal 0.2g/gal 38 lg/gal 0.5g/gal 55 lg/gal l.Og/gal 154 1700F. .25g/gal 0 61 - 95 .25g/gal .25g/gal 159 - 50 percent plugged When trimethylcarboxymethoxysuccinate and methyl-cyclopentadlenyl manganese were used ln the te~t fuel the following results were obtained.
..TABLE III
Trimethyl ester of carboxy-methoxysuccinic TemP~ Mh conc. acld cenc.
1600F. lg/gal lg/gal me catalyst life (tlme to p~ug the cataly~t) was extended about 50 percent As demonstrated by the data ln Tables ~ and III
when the triesters of carboxymethoxy~uccinic acld o~ the type descrlbed above are blended wlth ~asollne contalnlng cyclo---2 o--pentadlenyl manganese antlknocks unexpecte~ result~ are obtained in the alleviatlon of cataly~t plug~lng.
m e amount of antlplugging compound, as for example, triethylcarboxy~ethoxysuccinate, sufficient to reduce the plu~glng of the catalyst i8 at least to ~ome extent dependent upon the amount of manganese present in the gQsoline and on the lnIet exhaust temperature. Generally, the greater the concentration of manganese and the higher the temperature the greater the am~unt of antlplug~lng ^ompound needed to reduce plugging of the catalyst. Thus, for example, 0.2 gram o~ triethylcarboxymethoxysuccinate per gallon of gasoline i~
~u~ficlent to extend the life of the catalyat from about 50 hour~ to about 200 h~urs at a temperature of 1,500F. wlth unleaded gasoline contalning 1 gram of m~nganese per gallon or ga~oline. However. with the same concentration of manganese, but at a temperature of l,600F., 1 g/gal of trlethylcarboxy-methoxysucclnate 18 needed to effectlvely reduce plugglng of the catalyst.
m e lower limit at whlch the antlplugging compounds Or the present lnvention, such as the trlethyl esters Or carbo~ymethoxy~uccinic acid, are effectlve to reduce plu~ging i~ about 0.01 g/gal. Preferably, the amount of the compound i~ greater than 0.0~ ~ gal, and more preferably greater than 0.125 g/gal. There is no real upper l~mit on the concentration Or the antiplugging compound, and, accordinglyl the upper llmit iB re~tricted by such ~econda~y consideratlons aB
econo~ics, etc. Ho~ever, 1.0 g/g~l of the antiplugging compounds, such as the trlethyl ester o~ carboxymethoxy-~uccinic acid, is 6uf~icient to reduce plug~in~ of the catalyst when u~ing a ~asoline conta~nlng 1 g/gal of mangane~e at a temperature of l,700F. Thu~, ~lnce the amount of the antiplugging compound, such as the aforementloned triethyl e~ter, i~ qulte dependent upon the concentration of the mangane~e, ~or practlcal purpo~es the upper limit ls about 10 g/~al.
It 1~ convenient to util~ze addltive ~luid mixtures composed of cyclopentadlenyl manganese tricarbonyl antlknock agents and antiplugging agent~ having the general formula H
ROOC-C-H H
ROOC-C O - C-COOR
H H
whereln R 1~ independently selected from hydrogen, metal~, ammonlum and 8ubstltuted ammonlum catlon, hydrocarbyl radical~, ~nd substituted hydrocarbyl radlcal~. These additive fluid mixture~ are added to low-lead or unleaded gasollne. In other words, part of the present invention are antiknock-antlplug fluids which comprise cyclopentadlenyl manganese tricarbonyl antiknock agents and the antlplugglng agents of the type de~cribed hereinabove.
U~e of ~uch antiknock-antlplug fluids in addition to resultlng ln great convenience ln ~torage, handling, transportation~ blending with fuels, and BO' forthJ also are potent concentrates whlch serve the multipurpose functlons of belng useful ~8 antlknocks, and catalyst pluggine reducers.
In the~e fluld compositions the weight ratio of ~anganese-to-antiplugging agent can vary from about 0.0~ gram r -22 ~

o~ antiplugging agent such a8 trlethyl carboxymethoAYysuccinate to 1 ~ra~ oA4 mangane~e or even 0.01 gram OA~ the antlplugglng agent ~uch as triethylcarboxymethoA~ys~ccA~n~te to 1 ~ram OA~
man~ane8e on the one hand to abGut 10 grams of the ~ntlplugglng a~ent such a~ triethylcarboxymethoxysuccinBte to ~bout 1 gram Or manganese on the other hand. Some exampleg OA~ preA~erred A~luids are 0.03 gram8 OA~ trlethylcarboxymethoYy~uccin~te to 0.125 grams of mangane8e, 0. o6 grams of trlethylcarboAYymet 6uccinate to 0.125 gram OA~ manganese,- 0.2 gr~m Or triethyl-carboxymethoxysuccinate to 1 gram OA~ manganese~ 0.1 gra~ OA~
trlethylcarboxyme~ho~ysuccinate to 0.25 gra~A OA~ manganese, 0.5 gram OA~ trlethylcnrboxymethoAxy8uccinate to 1 gram OA~
~angane8e~ 1 gram OA~ trlethylcarboAYymethoxy8uccin~lte to 1 gram o~ mangane~eJ 1 gram o~t~nethylcarboxymethoxysuccinate to 1 gram of manganese~ and 2 gr~lms o~ trlethylcarboxyrlethoxy-succinate to 1 8r~m o* manganese. The flulds may optlonally cont~ln other additiYes such a8 ~ntloxidants, antlrust agent~, detergents, etc.~ as well a~ solvent~, e.g., a hydrocarbon to ~acllltate handling.
Although the preferred antiplugging compounds have the general ~ormula ROOC-C-H
. ROOC-C O C-COOR
H
~herein R bas ~een pre~iously described, it is believed that -2~-`~ 1058870 compounds havlng the skeletal ~tructure -OOC-C--OOC-C-O-C-COO-will have u~e~ul propertles in reducing the plugglng of exhaust catalysts.
Thu8 for example, one, some, or all o~ the carbon hydrogens can be replaced by other groups such as alkylsJ
cycloalkyls, aryls, aralkyls, and alkaryls. Furthermore, fiald carbon hydrogens may be substituted by halogen, hydroxyl, carboxyl, and amlno radicals. A limltlng factor regarding the numbers and types of group that can replace the carbon hydrOgen8 iB that these groups do not make the compound insoluble ln gasoline to ~uch a degree that an effective amount o~ compound cannot be added.
Although the compound~ of the present invention have the mo~t utllity when added to gasoline, they can al80 be used ln conJunctlon with other liquld petroleum distillate ruels such a~ kerosene, diesel ~uel, ~et englne fuel~ and the llke.
Claims to the inventlon follow.

-~4

Claims (40)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

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:

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 cyclo-pentadienyl 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:

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:

wherein R is independently selected from hydrogen and hydrocarbyl radicals.

13. me 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. me 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:

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:

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 cyclo-pentadienyl 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. me 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 cyclopenta-dienyl 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 said 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.