US3484217A - Exhaust emission reducing additive - Google Patents

Description

United States Patent 3,484,217 EXHAUST EMISSION REDUCING ADDITIVE James D. ONeill, Sonthfield, Mich., assignor to Ethyl Corporation, New York, N.Y., a corporation of Virginia No Drawing. Filed Oct. 17, 1966, Ser. No. 586,964 Int. Cl. Cl1/18, J/30 U.S. Cl. 44-69 7 Claims ABSTRACT OF THE DISCLOSURE Fuel composition containing a liquid hydrocarbon fuel and an exhaust emission and combustion chamber depositreducing benzylidene bisphenol additive; e.g.; 4,4-benzylidene bis(2,6-di-tert-butylphenol). The benzylidene bisphenol may also be contained in a tetraalkyllead antiknock fluid.

This invention relates to a fuel composition for use in internal combustion engines which results in reduced hydrocarbon emission in the exhaust gas and a reduced amount of combustion chamber deposits. In particular, this invention relates to a liquid hydrocarbon fuel containing a benzylidene bisphenol.

The exhaust gas of internal combustion engines contains some quantity of unburned hydrocarbons. Hydrocarbons are reported by researchers to react with ozone in the atmosphere, forming irritants. Research has attributed photochemical smog to the presence of hydrocarbons in the atmosphere. Thus, a need exists for a method to reduce the amount of hydrocarbon introduced into the atmosphere from the exhaust gas of internal combustion engines. Previous means of accomplishing this have been through the secondary oxidation of the unburned exhaust hydrocarbons employing catalytic oxidizing methods or direct flame oxidation in the exhaust system. If the amount of unburned hydrocarbons initially in the exhaust can be reduced, the need for secondary oxidation is diminished. Previous attempts to reduce the initial hydrocarbon content of the exhaust gas have concentrated on mechanical methods such as improved carburetion. The present invention relates to a method of reducing exhaust emission and engine deposits through the use of a fuel containing an exhaust emission reducing additive.

An object of this invention is to provide an improved fuel composition. A further object is to provide a fuel composition which, when used to operate an internal combustion engine, results in reduced hydrocarbon emission.

A still further object is to provide a fuel that will substantially reduce the amount of deposits formed in the combustion chamber of engines.

These and other objects are accomplished by providing an improved fuel composition comprising a major portion of a liquid hydrocarbon fuel and a minor quantity sufficient to reduce exhaust emission and combustion chamber deposit of a benzylidene bisphenol having the formula:

3,484,217 Patented Dec. 16, 1969 ice wherein R R R R R and R are independently selected from the group consisting of hydrogen, alkyl radicals containing 1-20 carbon atoms, arakyl radicals containing 7-20 carbon atoms, ar'yl radicals containing 6-20 carbon atoms, cycloalkyl radicals containing 6-20 carbon atoms and halogen radicals having an Atomic No. from 17-53; and R is selected from the group consisting of hydrogen and lower alkyl radicals containing from 1-3 carbon atoms.

Some examples of these compounds are:

2,2- (p-nonyl benzylidene -bis- (4-methyl-6-tertbutyl-phenol) 2,2,4,6'-tetra-isopropyl-2,4'-benzylidene bisphenol 2,4-di-methyl-2',6-di-cyclohexyl-2,4'-benzylidene bis-phenol 4,4'-(oa-rnethyl-4-SeC-I10nyl benzylidene)-bis-(2-seceicosyl-phenol) 4,4-benzylidene bisphenol 4,4- u-n-propyl-4-sec-dodecyl benzylidene) -bis-2- tert-butyl-S-methylphenol 2,2'-benzylidene bis(6-sec-butylphenol) 2,2-benzylidene bis(S-methylphenol) 5-methyl-3-methyl-2,4-(p-nonyl benzylidene)bisphenol 4,4'-benzylidene bis 2- a-methylbenzyl) phenol] 4,4'- (4-chloro benzylidene -bis- 2-chloro-6-tertbutylphenol) 4,4-- 3 ,5 -di-bromo benzylidene bis (2-bromophenol) 2,2- a-methyl-2,5-di-chloro benzylidene bis [4-secnonyl-6- (4-sec-nonylcyclohexyl phenol] In a preferred embodiment of this invention, R and R are bonded to the position ortho to the phenolic hydroxyl radical and the benzylidene radical bonds between the para carbon atoms of the phenolic benzene rings. These compounds have the formula:

wherein R and R are selected from the group consisting of alphahybranched alkyl radicals containing 3 to 20 carbon atoms, alphahybranched aralkyl radicals containing 8 to 20 carbon atoms, cyclo alkyl radicals containing 6 to 20 carbon atoms, and R and R are selected from the group consisting of alkyl radicals containing 1 to 20 carbon atoms, cycloalkyl radicals containing 6 to 20 carbon atoms, aralkyl radicals containing 7 to 20 carbon atoms and halogens having an atomic number from 17 to 53, and R and R are the same as in Formula I, and R is hydrogen. Examples of these preferred compounds include:

4,4-benzylidene bis(2-tert-butyl-6-chlorophenol) 4,4'- (2,4-di-bromo benzylidene bis( 2-methyl-6-tertnonylphenol) 4,4-(4-sec-nonyl benzylidene)bis(2,6-di-sec eicosylphenol) 4,4'-(p-sec-dodecyl benzylidene)bis(2-methy1- 6-sec-dodecylphenol) 4,4'- 2-chloro-4-amyl benzylidene bis (2,6-di-secbutylphenol) 4.4-- (4-sec-octyl benzylidene bis (2-methyl-6-cyclohexylphenol) 4,4'-(4-tert-nonyl benzylidene)bis[Z-methyLG-(a-methyI- benzyl)phenol] 2 methyl 6 (a-methylbenzyl-2,6'-sec-eicosyl-4,4-(4- chloro benzylidene)bis(phen0l) A highly preferred class of emission and deposit-reducing benzylidene bisphenols of this invention are those having Formula II wherein R R R and R are alphabranched C alkyl radicals, C alkyl radicals, C cycloalkyl radicals, or C alpha-branched aralkyl radicals; R and R are C alkyl radicals or halogen radicals; and R is hydrogen. Some examples of these highly preferred compounds are:

4,4'- t-methyl benzylidene bis 2,6-di-tert-butylphenol) 4,4'-(4-eicosyl benzylidene)bis(2,6-di-sec-butylphenol) 4,4'-(4-chloro benzylidene) bis(2,6-di-sec-eicosy1phenol) 4,4'-(4-bromo benzylidene)bis(2,6-di-cyclohexylphenol) 4,4-(4-nonyl benzylidene bis [2-isopropyl-6 (ix-methylbenzyl)phenol] 4,4 (3,5 di-chloro benzylidene)bis[2-sec-butyl-6-(amethyl-4-sec-dodecyl benzyl)phenol] The most preferred benzylidene bisphenol is 4,4'-benzylidene bis(2,6-di-tert-butylphenol) The benzylidene bisphenols are readily made by the reaction of the appropriate phenol with a carbonyl compound in a solvent using an acid or a base catalyst. A suitable process is described by Filbey et al. in US. 2,807,- 653, Sept. 24, 1957. The following example will serve to illustrate the process for preparing the additives.

EXAMPLE 1 In a reaction vessel equipped with stirrer, condenser, thermometer and reagent-introducing means was placed 6.6 parts of potassium hydroxide dissolved in 400 parts of isopropanol. To this solution maintained under a nitrogen atmosphere was added 206 parts of 2,6-di-tert-butylphenol and 53 parts of benzaldehyde. Toward the end of the benzaldehyde addition, solids began to appear in the reaction vessel. After stirring for two hours at 40 C., the solids were filtered off to give a good yield of 4,4- benzylidene bis(2,6-di-tert-butylphenol) This method can be adapted to prepare other benzylidene bisphenols. The starting materials are readily prepared by methods known in the art.

The additives of this invention can be used to reduce emissions and combustion chamber deposits resulting from the use of a broad range of liquid hydrocarbon fuels including both spark ignition and diesel fuels. It is especially useful in gasoline used in spark ignition engines. These liquid hydrocarbon fuels have a boiling range of from about 95 to about 400 F. and contain aliphatic, aromatic, olefinic and naphthenic hydrocarbons. The hydrocarbon fuels may contain other materials frequently used in such fuels. For example, the fuels may contain antiknock agents such as tetraethyllead, tetramethyllead, triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, trivinylethyllead, ferrocene, methyl ferrocene, iron carbonyl, methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl nickel nitrosyl, N,N- dimethylaniline, and the like. When metallic antiknock agents are employed, the fuels generally contain a scavenging agent. A particularly useful scavenging agent when lead alkyls are employed are the halohydrocarbons such as ethylenedichloride, ethylenedibromide, and the like. An especially useful fuel in this invention is a fuel containing from 0.5 to 6 grams of lead per gallon as tetraalkyllead and from 1.5 to 2.5 gram atoms of chlorine as a chlorohydrocarbon per gram atom of lead and from 0.5 to 1.5 gram atoms of bromine as a bromohydrocarbon per gram atom of lead. Preferred tetraalkyllead antiknocks are tetraethyl lead and tetramethyl lead. The most preferred chlorohydrocarbon is ethylenedichloride, and the most preferred bromohydrocarbon is ethylenedibromide.

It is often desirable to include an induction aid in the gasoline compositions containing the benzylidene bisphenols. This is because some of the additives are high molecular weight, and, with a normal vaporization type carburetor, induct into the combustion chamber with difficulty. This problem is not encountered in diesel engines or fuel injected spark ignited engines. Suitable induction aids are solvents boiling in the range of from about 300-500 P. such as kerosene, alkylated aromatics, for example, isopropyl benzene, diethyl benzene, and the like; ketones boiling from 300500 P. such as cyclohexanone, ethylcyclohexanone, ethyl-n-butyl ketone diisobutyl ketone, and the like; ethers boiling in the 300- 500 F. range such as diethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, and the like; ether alcohols such as ethylene glycol monoisobutyl ether, ethylene glycol mono-n-butyl ether; esters such as isoamyl propionate, cyclohexyl acetate, furfuryl acetate, and the like. Of the foregoing examples, the preferred induction aids are kerosenes boiling from 300 to 500 F.

The amount of induction aid employed varies from none to about 5 percent depending upon the ease of inductibility and the carburetor design. When an aid is used, a preferred concentration is from 0.1 to 5 percent. A more preferred range is from about 0.2 to 1 percent.

The fuels can also contain deposit modifying agents such as phosphorus-containing additives, for example, tricresylphosphate, cresyldiphenylphosphate, trimethylphosphate, dimethylcresylphosphate, tris(B-chloropropyl) phosphate, and the like.

The fuels frequently contain antioxidant additives such as 2,6 di-tert-butylphenol; 2,6 di-tert-butyl-4-methylphenol, 4,4 methylenebis(2,6 di-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-tert-butylphenol), phenylenediamines; p-nonylphenol; mixed alkylated phenols, 4,4-thiobis(3-methyl-6-tert-butylphenol), and the like.

Other materials can be present in the fuel such as deicers, metal deactivators, pour point depressants, boron esters, nickel alkyl phosphates and dyes.

The following examples illustrate the preparation of typical improved fuel compositions of this invention.

EXAMPLE 2 To a blending vessel is added 1000 gallons of a gasoline having the following properties:

Boiling range F 101-375 Research octane number 93 Volume percent:

Aromatics 3 8 Olefinics 10 Aliphatics 5 2 To this gasoline is added a tetraethyllead antiknock agent containing two gram atoms of chlorine as ethylenedichloride per gram atom of lead and one gram atom of bromine as ethylenedibromide per gram atom of lead. The quantity of tetraethyllead antiknock agent added is sufficient to provide 3.17 grams of lead per gallon of fuel. There is then added sufficient 4,4'-benzylidene bis(2,6-ditert-butylphenol) to give a concentration of 0.25 weight percent. There is then added 0.25 weight percent of cycld hexanone as an induction aid. The mixture is agitated until thoroughly mixed, resulting in a gasoline having reduced exhaust emission properties.

EXAMPLE 3 To a blending vessel is added 1000 gallons of a reformate gasoline having the following properties: Boiling range F 94-403 Research octane number 97 Volume percent:

Aromatics 62 Olefinics 5 Aliphatics 33 mixture of butylated phenols containing about 75 percent 2,6-di-tert-butylphenol, such that the gasoline contains 0.1 weight percent of the antioxidant mixture. Then 0.05 weight percent of 4,4-(p-nonylbenzylidene)bis(2,6- di-tert-butylphenol) together with 1 percent of diethylene glycol diethyl ether is added and the mixture thoroughly stirred, resulting in a gasoline giving reduced emission and combustion chamber deposits Weight when used to operate a spark ignition internal combustion engine.

Good results are also obtained in the above example when other benzylidene bisphenols such as those previ ously listed are employed as the emission and deposit-reducing agent.

EXAMPLE 4 To a blending vessel is added 1000 gallons of a gasoline having the following properties:

Boiling range F 103399 Research octane number 89 Volume percent:

Aromatics 21 Aliphatics 63 Olefins 16 To this gasoline is added an antiknock fluid as shown in Example 7 in quantities sufficient to give a lead concentration of 3.0 grams per gallon as tetraethyl lead. This addition concurrently adds 4,4-benzylidene bis(2,6-ditert-butylphenol) in an amount equal to 0.05 weight per- EXAMPLE 5 To a blending vessel is added 1000 gallons of gasoline having the following properties:

Boiling range F 98-410 To this gasoline is added 0.25 weight percent of a kerosene having a boiling range of 356-450 F., visc. at 100 SUS of 73, flash point of 320 F., pour point 30 F., specific gravity 0.893, Conralson carbon of 0.02 weight percent and Kauri-butanol No. of 28. There is then added 2.6 grams of lead per gallon as a mixture of lead alkyls having the approximate composition of 6.25 percent tetramethyl lead, 25 percent ethyltrimethyl lead, 37.5 percent diethyldimethyl lead, 25 percent methyltriethyl lead, and 6.25 percent tetraethyl lead. There is then added 0.3 theories of phosphorus as tricresyl phosphate. Following this is added 4,4-benzylidene bis(2-methyl-6-sec-cetylphenol) in an amount equal to 0.5 weight percent of the mixture. The result is a gasoline having reduced emissionincreasing and combustion chamber deposit-forming properties.

EXAMPLE 6 To a blending vessel is added 1000 gallons of a diesel fuel having a boiling range of from 430572 F., and a cetane number of 47. To this is added 0.3 weight percent amyl nitrate as a cetane improver. There is then added 0.2 weight percent of 4,4-benzylidene bis[(2,6-di(amethylbenzyl) phenol], resulting in a diesel fuel having re duced exhaust emission and deposit forming properties.

In any of the previous examples, the forementioned emission-reducing compounds can be employed, giving fuels having reduced emission properties. Also, the concentrations may be varied from those shown. In general, a concentration of from about 0.01 to 3 weight percent of the emission-reducing additive can be employed. A preferred concentration range is from about 0.05 to about 1 weight percent, and a most useful range is from about 0.1 to 0.5 weight percent.

An especially useful means of adding the benzylidene bisphenols to gasoline is to include them in the antiknock fluid concentrate which is normally added to gasoline so that the entire operation can be accomplished in a single blending step. These antiknock fluids contain an antiknock such as, but not limited to, tetraalkyl lead plus other materials which beneficially effect the use of the antiknock. Especially useful tetraalkyl lead antiknocks are tetraethyl lead, tetramethyl lead, mixtures thereof, alkyl leads containing both ethyl and methyl groups, and mixtures thereof. These antiknock fluids usually contain a halogen compound as a scavenger. The most frequently employed halogen scavengers are ethylene dichloride and ethylene dibromide. The quantities of these scavengers can be varied within a wide range, but the best results are obtained when the antiknock fluid contains from 0.5 to 2 theories of chlorine as ethylene dichloride and from 0 to 1.0 theories of bromine as ethylene dibromide. A theory is equal to 2 gram equivalents of halogen per gram mole of lead. In other words, one theory of halogen is sufficient to convert the lead in a tetraalkyl lead to lead dihalide.

An amount of benezylidene bisphenol is added to the antiknock fluid such that when the antiknock fluid is added to gasoline in an amount sufiicient to raise the octane number of the gasoline to the desired value there will also be included in the gasoline an emission and deposit reducing amount of the benzylidene bisphenol. A preferred range of benzylidene bisphenol concentration in the gasoline is from about 0.05 to 3 weight percent. Hence, a useful range of benzylidene bisphenol in tetraalkyl lead antiknock fluids is from about 0.45 to 27.2 parts of the benzylidene bisphenol per part of lead as tetraalkyl lead. This amount will supply from 0.05 to 3 weight percent of the benzylidene bisphenol when suflicient antiknock fluid is added to the gasoline to supply 3 grams of lead per gallon as tetraalkyl lead. When more or less lead is desired, the concentration range of benzylidene bisphenol in the fluid can be varied accordingly to furnish the desired benzylidene bisphenol concentration. Following are some representative examples of antiknock fluids containing exhaust and deposit reducing benzylidene bisphenols.

EXAMPLE 7 An antiknock fluid is prepared by blending the following ingredients:

Parts Tetraethyllead 1000 Ethylene dibromide 290 Ethylene dichloride 306 4,4'-benzylidene bis(2,6-di-tert-butylphenol) 290 Kerosene Orange dye 5 EXAMPLE 8 An antiknock fluid is prepared by blending the following ingredients:

Parts Tetramethyllead 1,000

Ethylene dibromide 295 Trimethyl phosphate 4,4'-(p-nonyl benzylidene) bis(2,6-di-sec-dodecylphenol) 17,400

Kerosene 200 The above examples are merely illustrative of the typical antiknock fluids which can be prepared. Similar antiknock fluids can be prepared employing other antiknock agents such as triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, trivinylethyllead, ferrocene, methylferrocene, iron carbonyl, methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl nickel nitrosyl, N,N- dimethylaniline, and mixtures of any of the foregoing. Likewise, any of the previously described benzylidene bisphenols can be employed in these antiknock fluids in quantities that will give the desired concentration in the final gasoline blend. These concentrations are easily determined by those experienced in blending additives in gasoline.

Tests have been conducted to demonstrate the useful exhaust emission properties of the present compounds. In these tests, a single cylinder overhead valve engine, having a :1 compression ratio and a 36 cubic inch displacement, was operated on a typical commercial gasoline containing 3.17 grams of lead as a commercial tetraethyllead antiknock mixture containing one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide. The engine was idled for seconds and then run at percent wide open throttle for seconds under the following conditions.

Air/ fuel ratio 13 Rpm. 1370 Ignition timing BTC 15 lowed by another test on the fuel, again without the emission additive, to reconfirm the baseline. Using this procedure, the following results in terms of the percent reduction in exhaust hydrocarbon emission increase and total combustion chamber deposits were obtained using emission reducing additives of this invention.

Reduction of Emission Deposit increase, weight Additive Cone. percent (mg.)

4,4'-benzy1ideue bis(2,6-di-tertbutylphenol) 0. 2 58 63 Do l 0. 05 48 20 1 In this test, 0.25% of kerosene was also included in the test fuel.

As these results show, the emssion-reducing additives of the present invention effectively reduce both exhaust emission increase and engine deposits.

1 claim:

1. A liquid hydrocarbon fuel for an internal combustion engine, said fuel containing an exhaust emission and combustion chamber deposit-reducing amount of a benzy idene bisphenol having the formula:

wherein R and R are independently selected from the group consisting of alpha-branched alkyl radicals containing 3 to 20 carbon atoms, alpha-branched aralykl radicals containing 8-20 carbon atoms, cycloalkyl radicals containing 6-20 carbon atoms, and R and R are selected from the group consisting of alkyl radicals containing 120 carbon atoms, cycloalkyl radicals containing 620 carbon atoms, aralkyl radicals containing 7-20 carbon atoms, and halogen radicals having an atomic number from 1735, and R and R are selected from the group consisting of hydrogen, aryl radicals containing 6-20 carbon atoms, R3 and R4.

2. The composition of claim 1 wherein said benzylidene bisphenol is 4,4'-benzylidene bis(2,6-di-te1t-butylphenol).

3. The composition of claim 2 wherein said liquid hydrocarbon fuel is a liquid hydrocarbon of the gasoline boiling range.

4. The composition of claim 3 containing from 0.15 percent of an induction aid selected from the group consisting of kerosenes boiling from 300500 F., ketones boiling from 300500 F., aromatic hydrocarbons boiling from 300500 F.; ethers boiling from 300500 F., ether alcohols boiling from 300-500 F., and esters boiling from 300500 F.

5. The composition of claim 3 wherein said liquid hydrocarbon fuel of the gasoline boiling range contains from 0.5 to 6 grams of lead per gallon as a tetraalkyl lead antiknock.

6. A tetraalkyllead antiknock fluid containing a bcnzylidene bisphenol having the formula:

wherein R and R are independently selected from the group consisting of alpha-branched alkyl radicals containing 320 carbon atoms, alpha-branched aralkyl radicals containing 8-20 carbon atoms, cycloalkyl radicals containing 620 carbon atoms, and R and R are selected from the group consisting of alkyl radicals containing 1-20 carbon atoms, cycloalkyl radicals containing 620 carbon atoms, aralkyl radicals containing 7-20 carbon atoms, and halogen radicals having an atomic number from 1735, and R and R are selected from the group consisting of hydrogen, aryl radicals containing 620 carbon atoms, R and R in an amount such that when said antiknock fluid is added to gasoline in quantities sufficient to provide from 0.5 to 6.0 grams of lead per gallon of gasoline as said tetraalkyllead there will be co-added to said gasoline an exhaust emission and combustion chamber deposit reducing quantity of said benzylidene bisphenol.

7. The tetraalkyl lead antiknock fluid composition of claim 6 comprising tetraethyl lead, from 0.5 to 2.0 theories of chlorine as ethylene dichloride, from 0 to 1.0 theory of bromine as ethylene dibromide, and from 0.5 to parts of 4,4-benzylidene bis(2,6-di-tert-butylphenol) per part of lead as said tetraethyl lead.

References Cited UNITED STATES PATENTS 2,515,906 7/1950 Stevens et al. 2,570,402 10/1951 Stevens et al. 2,678,302 5/1954 Beaver et al. 2,807,653 9/1957 Filbey et al. 2,829,175 4/1958 Bowman et al.

DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. R3 and R4.

2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5A b 17 Dated D m er 16, 1969 mventoflx) James D. O'Neill It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 46, the formula should be labeled (II) Line 47, and Line +8, "alphahybranched" should read alpha-branched Column 4, line 7, insert a comma after "ketone". Column 7', line 63, in Claim 1, that portion of the formula reading:

OH should read OH dlGNED ANu SEALED JUL 2119 bEAL Atteat:

Edward M. Fletcher, It. WIN-IAN E- 'SOHIYNJR, J3- flommissinnw nf Palms Attesting Officer