US2994595A - Motor fuel compositions - Google Patents

Description

United States Patent 2,994,595 MOTOR FUEL COMPOSITIONS Albert C. Condo, Jr., James B. Hunter, and William S.

lfoung, Newtown Square, Pa., assignors to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed Mar. 2, 1960, Ser. No. 12,246 4'Claims. (Cl. 44-63) This invention relatm to improvements in motor fuels in the gasoline boiling range and in particular to such motor fuels, the effect of which will be to reduce the octane requirement increase and thus inhibit surface ignition in internal combustion engines. Specifically, this invention has to do with motor fuels to which has been added an organo-fluoro-nitrogen compound.

The recent trend in internal combustion engines has been toward higher compression ratios for which there is required a motor fuel having a compensating octane number. Moderately high octane number fuels have been found to satisfy the octane requirements of the engines while the engines are new but after only a few months of operation, i.e. two to six months, these same engines have beeln found to require increasingly higher octane number fue s.

This increase in octane requirement that an engine may experience following this relatively short period of use is termed octane number requirement increase and is usually abbreviated to ORI. ORI is the result of combustion chamber deposits. These deposits decrease the physical volume of the combustion chamber and thus in effect increase the compression ratio of the engine which in turn raises the octane number requirement of the engine. They also have a heat insulating effect which reduces the rate of heat transfer from the combustion chamber to the cooling system. This latter causes excessive heat to be transferred to the incoming air-fuel mixture which sensitizes the mixture and promotes autoignition. Thus, as the engine is operated the amount of deposits increases and the octane number requirement increases. Moreover, it has been suggested that these deposits produce hot spots in the combustion chamber with resultant preignition; that is, the hot, incandescent spot in the combustion chamber causes the explosion of the gasoline-air mixture instead of the explosion being caused by the firing of the spark plug. This ignition generally occurs prior to the firing of the spark plug and hence this phenomenon is termed preignition or surface-ignition. Preignition or surface-ignition produces an efiect similar to that of the knocking of low octane number fuels in a high octane requirement situation. 1

Accordingly it is an object of this invention to provide a motor fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and a minor amount of an additive suflicient to reduce the octane requirement increase and to inhibit surface-ignition in an internal combustion engine.

It is a further object of this invention to provide a motor fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and a minor amount of an organo-fluoro-nitrogen compound sufficient to reduce the octane requirement increase and inhibit surface-ignition in an internal combustion engine.

Further objects of this invention will be apparent from the description and claims that follow.

In accordance with the instant invention an organofluoro-nitrogen compound is added to gasoline in minor amounts. These compounds are added preferably to a gasoline containing tetraethyl lead since the bulk of the gasoline presently being produced is leaded and it is the improvement of such fuels that is the primary purpose of this invention. The tetraethyl lead antiknock agent is "ice employed in conventional amounts and contains the usual scavenging agents. In addition, the gasoline may contain minor and conventional amounts of other additives such as solvent oils, gum inhibitors, dyes, lead stabilizers, carburetor anti-icing agents and similar additives.

The amount of organo-fluoro-ni-trogen compound which is to be added to the gasoline is preferably measured in grams of compound per gallon of gasoline. It has been found that the octane requirement increase of an internal combustion engine may be substantially reduced by adding to the gasoline an organo-fluoro-nitrogen compound in amounts ranging between about 0.1 gram of compound per gallon of gasoline to about 4.0 grams of compound per gallon of gasoline. For best results, however, amounts ranging between 0.15 gram of compound per gallon of gasoline to about 1.5 grams of compound per gallon of gasoline are preferred.

The organo-fluoro-nitrogen compounds suitable for use as gasoline additives in accordance with the instant invention have the following general formula:

wherein R R and R are radicals selected from the group consisting of ,alkyl, aryl, alkaryl, aralkyl, fluoro: alkyl, fluoro-alkaryl and fluoro-aralkyl radicals. The total number of carbon atoms in the molecule ranges between 6 and 60 and the total number of fluorine atoms in the molecule ranges between 3 and 20. In addition, any carbon atom which is fluoride substituted bears at least 2 fluorine atoms and in the case of terminal carbon atoms the carbon may bear 3 fluorine atoms. In general, these compounds are prepared by reacting a fluoro-alcohol with a cyanuric chloride.

The preferred compound for use in combination with the gasoline component of this invention is tris(trifluoroethyl) cyanurate which has the following structural formula: V i

' OCHtCFa l C FBCHZQ C minors c-oomom H CFaCHrO-C II onsomo-o o-o CHHCH! C CH3 to further define its scope and usefulness, which examples are not to be construed as limitative.

EXAMPLE I Various fuel compositions were tested in a Briggs and Stratton, Model 5-8, single cylinder, air cooled L-head internal combustion engine. The base gasoline employed was a commercial premium gasoline-containing a blend of C hydrocarbons, catalytically reformed naphtha and catalytically cracked naphtha together with isobutanebutylene alkylate. This gasoline had a boiling range of 90 F. to 420 F. and contained 3 cc. of conventional tetraethyl lead fluid per gallon. The lubricant employed was a conventional premium grade detergent-inhibitor additive lubricating oil of SAE 20 grade.

The engine was first run for 20 hours on the conventional gasoline fuel during which time the octane requirement of the engine increased from 62 to 71, i.e., an increase of 9 octane numbers. After the run the engine was dismantled and the interior surfaces of the combustion chamber and exhaust valve were cleaned of deposits. A new spark plug was used for each run.

After reassembly the engine was operated for a period of 20 hours on gasoline containing 1.5 grams of tris(trifluoroethyl) cyanurate per gallon of the gasoline. During this run the octane requirement of the engine increased only 2 numbers, i.e., from 62 to 64. 'After disassembly, cleaning and reassembly the engine was operated for 20 hours on the same conventional gasoline which contained no additive specifically to reduce ORI. During this run the octane requirement of the engine increased from 62 to 72, i.e., an increase of 10 octane numbers. After the run the engine was dismantled and the internal surfaces of the combustion chamber and exhaust valve were cleaned of deposits.

After reassembly the engine was operated for a period of 20 hours on the same conventional gasoline which contained-0.75 gram of tris (trifluoroethyl) cyanurate per gallon of gasoline. During this run the octane requirement of the engine increased only 4 numbers, i.e., from 62 to 66.

Each type of run described above was repeated a number of times in a randomized order with the ORI determined each time and with disassembly, cleaning and reassembly of the engine between each run. The results of these runs are set forth in Table I below.

These data clearly show that when an engine is operated with a conventional gasoline containing no additive to specifically reduce ORI, the octane requirement increase of the engine is substantially higher than when the same engine is operated with a similar fuel containing the preferred amounts of organo-fluoro-nitrogen compound according to this invention. In addition, these data show that it is the addition of the organo-fiuoro-nitrogen compound which elfects the reduction in ORI since a blank run was performed both before and after the actual testing of the preferred compounds of this invention.

EXAMPLE II The same fuel and one of the preferred additive-fuel combinations employed in Example I were employed in a series of 60 hour runs in the same test engine used in Example I. The initial octane requirement of the engine was determined before the start of each test run and after each 20 hours of operation. The engine was not disassembled and cleaned until it had operated for the full 60 hours. The results of these tests are set forth in Table II below.

These data clearly show that the ORI of an internal combustion engine is substantially reduced, even under conditions of continuous operation for extended periods of time, when operated employing a gasoline fuel containing an organo-fluoro-nitrogen compound according to the teachings of the invention.

'We claim:

1. A gasoline motor fuel comprising a major amount of hydrocarbons boiling in the gasoline boiling range and a minor amount of an organo-fluoro-nitrogen compound sufficient to reduce octane requirement increase in an internal combustion engine, the organo-fluoronitrogen compound having the general formula:

wherein at least one of the radicals R R and R are fluorine-substituted and are selected from the group consisting of alkyl, aryl, .alkaryl, aralkyl, fluoro-alkyl, fluoroalkaryl, and fluoro-aralkyl, the total number of carbon atoms in the molecule ranges between 6 and 60, the total number of fluorine atoms in the molecule ranges between 3 and 20, and .each fluorine substituted carbon atom has at least 2. fluorine atoms attached thereto.

2. A gasoline motor fuel comprising hydrocarbons boiling in the gasoline range and containing tetraethyl lead antiknock agent together with an organo-fluoronitrogen compound in an amount ranging between about 0.10 to about 4.00 grams of organofluoro-nitrogen compound per gallon of gasoline, the organo-fluoro-nitrogen compound having thegeneral formula:

wherein at least one-of the radicals R R and R, are fluorine-substituted and are selected from the group consisting of .alkyl, ,aryl, alkaryl, aralkyl,-fluoro-alkyl, fluoroalltaryl, and fluoro-aralkyl, the total number of carbon atoms in the molecule ranges between 6 and 60, the total number of fluorine atoms in the molecule ranges between 3 and 20, and each fluorine substituted carbon atom has at least two fluorine atoms attached thereto.

3. A gasoline motor -fuel comprising hydrocarbons boiling in the gasoline range and containing tetraethyl lead antiknock agent together with tris(trifluoroethyl) cyanurate in an amount ranging between about 0.10 to about 4.00 grams of tris(trifluoroethyl) cyanurate per gallon of gasoline.

4. A gasoline motor fuel comprising hydrocarbons boiling in the gasoline range and containing tetraethyl lead antiknock agent together with tris(trifiuoroethyl) cyanurate in an amount ranging between about 0.15 to about 1.5 grams of tris(trifiuoroethyl) oyanurate per gallon of gasoline.

References Cited in the file of this patent UNITED STATES PATENTS 2,682,541 Kaiser June 29, 1954 1 2,714,057 Chenicek July 26, 1955 21,741,606 Holt et a1. Apr. 10, 1956 2,861,990 Cleaver et a1. Nov. 25, 1958 UNITED STATES PATENT OFFICE 7 CERTIFICATE OF CORRECTION Patent No. 2,994,595 I August 1, 19 1 Albert 0.. Condo, Jr, et, a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,-

Column 2, line 34, for "fluoride" read fluorine Signed and sealed this 5th day of December 1961,

(SEAL) Attest: v

ERNEST W. SWIDER DAVID L. I

Attesting Officer Commissioner of Patents USCOMM-DC

Claims (1)

1. A GASOLINE MOTOR FUEL COMPRISING A MAJOR AMOUNT OF HYDROCARBONS BOILING IN THE GASOLINE BOILING RANGE AND A MINOR AMOUNT OF AN ORGANO-FLUORO-NITROGEN COMPOUND SUFFICIENT TO REDUCE OCTANE REQUIREMENT INCREASE IN AN INTERNAL COMBUSTION ENGINE, THE ORGANO-FLUORONITROGEN COMPOUND HAVING THE GENERAL FORMULA: