MOTOR FUEL CONTAINING A SUBSTITUTED ASPARAGINE
United States Patent 3773479
Motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing a minor amount of a substituted asparagine having the formula: ##SPC1## In which R and R' each represent a secondary or tertiary alkyl or alkylene radical having from about seven to about 20 carbon atoms.
US Patent References:
Inhibition of carburetor icing
Andress et al. - May 1961 - 2982629
Lubricant
Rense - November 1965 - 3215707
Inhibition of carburetor icing
Andress et al. - May 1961 - 2982629
Lubricant
Rense - November 1965 - 3215707
Inventors:
Dorn, Peter (Lagrangeville, NY)
Dille, Kenneth L. (Wappingers Falls, NY)
Dille, Kenneth L. (Wappingers Falls, NY)
Application Number:
05/205337
Publication Date:
11/20/1973
Filing Date:
12/06/1971
View Patent Images:
Export Citation:
Assignee:
Texaco Inc. (New York, NY)
Primary Class:
Other Classes:
252/392, 562/561, 562/574
International Classes:
C10L1/224; C10L1/10; C10L1/22; C10L1/18
Field of Search:
44/DIG.1,71,62 252/392 260/534R
Primary Examiner:
Wyman, Daniel E.
Assistant Examiner:
Shine W. J.
Parent Case Data:
This application is a continuation-in-part of application Ser. No. 40,401, filed on May 25, 1970, now abandoned.
Claims:
We claim
1. A motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing from about 0.0005 to 0.1 weight percent of a substituted asparagine having the formula: ##SPC4##
2. A motor fuel composition according to claim 1 in which R and R' represent secondary hydrocarbyl radicals.
3. A motor fuel composition according to claim 1 in which R and R' represent tertiary hydrocarbyl radicals.
4. A motor fuel composition according to claim 1 in which R and R' represent mixed secondary and tertiary hydrocarbyl radicals.
5. A motor fuel composition according to claim 1 in which R and R' represent secondary alkyl radicals having from 12 to 18 carbon atoms.
6. A motor fuel composition according to claim 1 containing N,N'-di-C14 -C15 -sec. alkyl asparagine.
7. A motor fuel composition according to claim 1 containing N,N'-di-C7 -C9 -sec. alkyl asparagine.
8. A motor fuel composition according to claim 1 containing N,N'-di-C15 -C20 -sec. alkyl asparagine.
9. A motor fuel composition according to claim 1 containing N,N'-di-C11 -C14 -sec. alkyl asparagine.
10. A motor fuel composition according to claim 1 containing N,N'-di-C12 -tert. alkyl asparagine.
11. A motor fuel composition according to claim 1 containing from about 0.002 weight percent to 0.02 weight percent of said asparagine.
1. A motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing from about 0.0005 to 0.1 weight percent of a substituted asparagine having the formula: ##SPC4##
2. A motor fuel composition according to claim 1 in which R and R' represent secondary hydrocarbyl radicals.
3. A motor fuel composition according to claim 1 in which R and R' represent tertiary hydrocarbyl radicals.
4. A motor fuel composition according to claim 1 in which R and R' represent mixed secondary and tertiary hydrocarbyl radicals.
5. A motor fuel composition according to claim 1 in which R and R' represent secondary alkyl radicals having from 12 to 18 carbon atoms.
6. A motor fuel composition according to claim 1 containing N,N'-di-C14 -C15 -sec. alkyl asparagine.
7. A motor fuel composition according to claim 1 containing N,N'-di-C7 -C9 -sec. alkyl asparagine.
8. A motor fuel composition according to claim 1 containing N,N'-di-C15 -C20 -sec. alkyl asparagine.
9. A motor fuel composition according to claim 1 containing N,N'-di-C11 -C14 -sec. alkyl asparagine.
10. A motor fuel composition according to claim 1 containing N,N'-di-C12 -tert. alkyl asparagine.
11. A motor fuel composition according to claim 1 containing from about 0.002 weight percent to 0.02 weight percent of said asparagine.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
Modern internal combustion engine design is undergoing important changes to meet stricter standards concerning engine and exhaust gas emissions. A major change in engine design recently adopted is the feeding of blow-by gases from the crankcase zone of the engine into the intake air supply to the carburetor just below the throttle plate, rather than venting these gases to the atmosphere as in the past. The blow-by gases contain substantial amounts of deposit-forming substances and are known to form deposits in and around the throttle plate area of the carburetor. These deposits restrict the flow of air through the carburetor at idle and at low speeds so that an overrich fuel mixture results. This condition produces rough engine idling, stalling and also results in excessive hydrocarbon exhaust emissions to the atmosphere.
2. Description of the Prior Art
U.S. Pat. No. 2,207,063 discloses the use of N(p-hydroxy-phenyl) dihydrocarbyl aspartate esters as gum inhibitors for hydrocarbon fuel oils.
U.S. Pat. No. 3,502,451 discloses motor fuel compositions containing polymers and copolymers of C 2 to C 6 unsaturated hydrocarbons and the corresponding hydrogenated polymers and copolymers having molecular weights ranging from about 500 to 3,500.
SUMMARY OF THE INVENTION
A class of hydrocarbon substituted asparagines are provided as carburetor detergents when employed in a liquid hydrocarbonaceous fuel for an internal combustion engine. These asparagines are characterized by having relatively long chain secondary and tertiary hydrocarbyl radicals substituted on the nitrogen atoms in the basic asparagine structure and appear to be unique in their detergency properties. The substituted asparagines in which the alkyl radicals are secondary alkyl radicals surprisingly also possess anti-icing and corrosion inhibiting properties.
The fuel composition of the invention mitigates or overcomes the important problem of deposits laydown in the carburetor of an internal combustion engine. When a gasoline of the invention is employed in a carburetor which has had a substantial build-up of deposits from prior operations, a severe test of the detergency property of the fuel, this gasoline is very effective for removing substantial amounts of the preformed deposits.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The substituted asparagine additive of the invention is represented by the formula: ##SPC2##
In which R and R' each represent a secondary or tertiary alkyl or alkylene radical having from seven to 20 carbon atoms. In a more preferred embodiment, R and R' represent the same or different secondary alkyl or alkylene radicals having from 12 to 18 carbon atoms.
There appears to be criticality in the structure of the substituted asparagine particularly with respect to the hydrocarbyl radicals represented by R and R'. The asparagines having carburetor detergency properties are those in which R and R' are secondary or tertiary hydrocarbyl or secondary or tertiary alkyl radicals. When R and R' are primary hydrocarbyl radicals, the compounds are generally too insoluble in gasoline to be effective. When R and R' are secondary hydrocarbyl radicals, the compounds also possess carburetor anti-icing and corrosion inhibiting properties. While it is convenient for R and R' to be the same hydrocarbyl radical it is sometimes advantageous for R and R' to be different hydrocarbyl groups or to be a mixture of secondary and tertiary hydrocarbyl radicals.
The additives of this invention have a number of advantages in addition to those noted above. The selected asparagines in gasoline are generally resistant to the formation of insoluble calcium soaps, to the formation of lead precipitates in the presence of terne metal and to the formation of emulsions in the presence of water.
The substituted asparagines are prepared by the reaction of maleic anhydride with a suitable amine according to the following reaction steps: ##SPC3##
In general, a mole of a suitable secondary or tertiary hydrocarbyl amine is reacted with maleic anhydride at a moderate temperature preferably dissolved in an organic solvent, such as benzene. Following the initial reaction step, the reaction mixture is cooled to a temperature of about 50°C or below and another mole of the hydrocarbyl amine is added to the reaction mixture. On the completion of this addition, the temperature of the reaction mixture is raised to the reflux temperature of the solvent and the mixture refluxed for an extended period until the reaction is complete. The yield of the substituted asparagine is substantially quantitative.
Examples of substituted asparagines which are effective in the present invention include:
N,N'-di-C 14 -C 15 secondary alkyl asparagine
N,N'-di-C 10 -C 14 secondary alkyl asparagine
N,N'-di-C 15 -C 20 secondary alkyl asparagine
N,N'-di-C 7 -C 9 secondary alkyl asparagine
N-sec.-octyl,N'-sec. lauryl asparagine
N-sec.-nonyl,N'-sec. octadecyl asparagine
N,N'-di-C 12 tertiary alkyl asparagine
N,N'-di-C 18 tertiary alkyl asparagine
N-C 14 -15 sec. alkyl-N'-C 12 tertiary alkyl asparagine
N-C 12 -14 tert. alkyl-N'-C 18 -22 tert. alkyl asparagine
N,N'-di-C 11 -C 14 -sec. alkyl asparagine
The fuel composition of the present invention comprises a mixture of hydrocarbons in the gasoline boiling range containing a minor amount of the substituted hydrocarbyl asparagine. In general, the additive is employed in the fuel composition at a concentration ranging from 0.0005 to 0.1 weight percent with the preferred concentration range being from about 0.002 to 0.02 weight percent. The motor fuel composition of the invention can contain additives conventionally employed in gasoline including anti-knock agents, corrosion inhibitors, anti-oxidants and upper cylinder lubricants. This fuel composition can also contain valve deposit inhibitors such as disclosed in U.S. Pat. No. 3,502,451 and this disclosure is incorporated in the present invention.
The following example illustrates the method of preparing the substituted asparagines of this invention.
EXAMPLE I
To a gently refluxing, stirred solution of 98 g (1.0 mole) maleic anhydride in 200 ml benzene there is slowly added dropwise 220 g (1.0 mole) of the C 14 -C 15 sec.-alkyl amine. After the addition is complete the solution is cooled to 50°C and another 220 g (1.0 mole) of the amine in 200 ml benzene is added dropwise. After this addition is complete the temperature is raised and the solution is refluxed for 5 hours. The solvent is then stripped to afford 535 g of a viscous, amber oil. The yield of the N,N'-di-C 14 -C 15 -secondary alkyl asparagine is quantitative.
Analysis Found Calc. %N 5.5 5.2 TAN 91.2 104 TBN 105 104 n D 20 1.4785
any gasoline suitable for a spark-ignited, internal combustion engine can be used in the practice of this invention. In general, the base fuel will consist of a mixture of hydrocarbons in the gasoline boiling range, i.e., from about 75° to 450°F. The hydrocarbon components can consist of paraffinic, naphthenic, aromatic and olefinic hydrocarbons obtained by thermal or catalytic cracking or reforming of petroleum hydrocarbons. This base fuel will generally have a Research Octane Number above 85 and preferably above 90.
The substituted asparagine additive of the invention was tested for its effectiveness as a carburetor Detergency Test. This test is run on a Chevrolet V-8 engine mounted on a test stand using a modified four barrel carburetor. The two secondary barrels of the carburetor are sealed and the feed to each of the primary barrels arranged so that an additive fuel can be run in one barrel and a base fuel run in the other. The primary carburetor barrels were also modified so that they had removable aluminum inserts in the throttle plate area in order that deposits formed on the inserts in this area would be conveniently weighed.
In the procedure designed to determine the effectiveness of an additive fuel to remove preformed deposits in the carburetor, the engine is run for a period of time usually 24 or 48 hours using the base fuel as the feed to both barrels with engine blow-by circulated to the air inlet of the carburetor. The weight of the deposits on both sleeves is determined and recorded. The engine is then cycled for 24 additional hours with base fuel being fed to one barrel, additive fuel to the other and no blow-by to the carburetor air inlet. The inserts are then removed from the carburetor and weighed to determine the difference between the performance of the additive and non-additive fuels in removing the preformed deposits. After the aluminum inserts are cleaned, they are replaced in the carburetor and the process repeated with the fuels reversed in the carburetor to minimize differences in fuel distribution and barrel construction. The deposit weights in the two runs are averaged and the effectiveness of the base fuel and of the additive fuel for removing deposits expressed in percent.
The base fuel employed in the following examples was a premium grade gasoline having a Research Octane Number of about 100 and containing 3 cc of tetraethyl lead per gallon. This gasoline consisted of about 25% aromatic hydrocarbons, 10% olefinic hydrocarbons and 65% paraffinic hydrocarbons and boiled in the range from about 90°F to 360°F.
The carburetor detergency test results obtained from the base fuel and the additive-containing fuels are set forth in the following Table. The additive-containing fuels contained the active detergent additive at a concentration of 20 PTB (pounds per thousand barrels of fuel), a concentration equal to about 0.01 weight percent.
TABLE I
Chevrolet Carburetor Detergency Test
Deposit Removal
Deposit Deposit Percent Run Build-up Removed effective ,mg* ,mg 1 Base Fuel 32.0 11.2 35 2 Base Fuel + 20 PTB 28.5 26.6 93 N,N'-di-C 14 -C 15 sec. alkyl asparagine * Built up with base fuel.
EXAMPLE II
A Chevrolet Carburetor Detergency Test was conducted employing a gasoline containing N,N'-di-C 12 -tert. alkyl asparagine as the detergent. The base fuel was similar to the base fuel employed in Table I above.
TABLE II
Chevrolet Carburetor Detergency Test
Run Fuel Percent Effective 1 Base Fuel 41 2 Base Fuel + 30 PTB N,N'-di-C 12 -tert. alkyl asparagine* 70 * Conventional non-dispersant gasoline additives also present.
This example illustrates that substituted asparagines, in which the alkyl radicals are tertiary alkyl radicals, are highly effective carburetor detergents.
The action of the substituted asparagines as anti-stalling, anti-icing additives was evaluated in a Glass Tube Carburetor Icing Bench Test consisting of a glass tube containing a simulated throttle plate so that cooled moisture saturated air from an ice tower is drawn through the simple glass tube gasoline carburetor by suction from a vacuum pump. The gasoline sample is placed on a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is usually 20 gauge. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation on the simulated throttle plate. The formation of ice on the throttle plate causes a pressure differential which is registered on a manometer. The fuels were rated in terms of seconds required to attain a pressure differential of 0.9 inch of mercury. Since most fuels stall in an engine in 1 to 4 minutes, 300 seconds is the maximum time taken for a run. A recording of 300 seconds denotes no simulated stall (pressure differential did not reach 0.9 inch of mercury), within the test period. Each fuel is run three times in succession and the average is reported. If the differences in runs are great the glass tube carburetor and test throttle are washed with alcohol and the runs repeated. A leaded winter-grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in about 50 to 90 seconds in this test. Additives which raise the stalling time to over 200 seconds are effective anti-stalling, anti-icing additives.
The following Table gives the carburetor anti-icing results of secondary alkyl asparagine derivatives of the invention in comparison to some ineffective asparagines. The additives were employed at a concentration of 20 PTB (pounds per thousand barrels of fuel).
TABLE III
ANTI-ICING TEST
Seconds to 0.9" Fuel Composition HG Manifold Vacuum 1. Base Fuel 72 2. Base Fuel + N,N'-di-C 10 -C 14 - sec. alkyl asparagine 217 3. Base Fuel + N,N'-di-C 14 -C 15 - sec. alkyl asparagine 248 4. Base Fuel + N,N'-di-C 12 - tert. alkyl asparagine 133 5 Base Fuel + N,N'-di-C 18 -C 22 - tert. alkyl asparagine 74
The rust inhibitng properties of fuel compositions containing secondary alkyl derivatives of the invention was determined in the Colonial Pipeline Rust Test. This test is a modification of ASTM Rust Test D-665-60 Procedure A. In the Colonial Pipeline Rust Test, a steel spindle is polished with non-waterproof fine emery cloth. The spindle is immersed in a mixture containing 300 cc fuel and 30 cc distilled water and is rotated at 100°F for 3.5 hours. The spindle is then rated visually to determine the amount of rust formation. A passing result is an average of less than 5% rust.
The results of this test are set forth in Table IV below. The additives were employed at a concentration of 20 pounds per thousand barrels of fuel.
TABLE IV
Colonial Pipeline Rust Test
Fuel Composition Percent Rust 1. Base Fuel 90, 100 2. N,N'-di-C 10 -C 14 -sec. alkyl asparagine trace, trace 3. N,N'-di-C 14 -C 15 -sec. alkyl asparagine trace, 5-10 4. N,N'-di-C 15 -C 20 -sec. alkyl asparagine trace, 5 5. N,N'-di-C 11 -C 15 -sec. alkyl asparagine 5, 0 6. N,N'-di-C 7 -C 9 -sec. alkyl asparagine 0, 0 7. N,N'-di-C 12 -tert. alkyl asparagine 100, 80 8. N,N'-did-C 18 -C 22 -tert. alkyl asparagine 80, 80
The foregoing test demonstrates the outstanding effectiveness of secondary alkyl derivatives of the invention in their rust inhibiting properties in contrast to related materials which are ineffective in these properties.
1. Field of the Invention
Modern internal combustion engine design is undergoing important changes to meet stricter standards concerning engine and exhaust gas emissions. A major change in engine design recently adopted is the feeding of blow-by gases from the crankcase zone of the engine into the intake air supply to the carburetor just below the throttle plate, rather than venting these gases to the atmosphere as in the past. The blow-by gases contain substantial amounts of deposit-forming substances and are known to form deposits in and around the throttle plate area of the carburetor. These deposits restrict the flow of air through the carburetor at idle and at low speeds so that an overrich fuel mixture results. This condition produces rough engine idling, stalling and also results in excessive hydrocarbon exhaust emissions to the atmosphere.
2. Description of the Prior Art
U.S. Pat. No. 2,207,063 discloses the use of N(p-hydroxy-phenyl) dihydrocarbyl aspartate esters as gum inhibitors for hydrocarbon fuel oils.
U.S. Pat. No. 3,502,451 discloses motor fuel compositions containing polymers and copolymers of C 2 to C 6 unsaturated hydrocarbons and the corresponding hydrogenated polymers and copolymers having molecular weights ranging from about 500 to 3,500.
SUMMARY OF THE INVENTION
A class of hydrocarbon substituted asparagines are provided as carburetor detergents when employed in a liquid hydrocarbonaceous fuel for an internal combustion engine. These asparagines are characterized by having relatively long chain secondary and tertiary hydrocarbyl radicals substituted on the nitrogen atoms in the basic asparagine structure and appear to be unique in their detergency properties. The substituted asparagines in which the alkyl radicals are secondary alkyl radicals surprisingly also possess anti-icing and corrosion inhibiting properties.
The fuel composition of the invention mitigates or overcomes the important problem of deposits laydown in the carburetor of an internal combustion engine. When a gasoline of the invention is employed in a carburetor which has had a substantial build-up of deposits from prior operations, a severe test of the detergency property of the fuel, this gasoline is very effective for removing substantial amounts of the preformed deposits.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The substituted asparagine additive of the invention is represented by the formula: ##SPC2##
In which R and R' each represent a secondary or tertiary alkyl or alkylene radical having from seven to 20 carbon atoms. In a more preferred embodiment, R and R' represent the same or different secondary alkyl or alkylene radicals having from 12 to 18 carbon atoms.
There appears to be criticality in the structure of the substituted asparagine particularly with respect to the hydrocarbyl radicals represented by R and R'. The asparagines having carburetor detergency properties are those in which R and R' are secondary or tertiary hydrocarbyl or secondary or tertiary alkyl radicals. When R and R' are primary hydrocarbyl radicals, the compounds are generally too insoluble in gasoline to be effective. When R and R' are secondary hydrocarbyl radicals, the compounds also possess carburetor anti-icing and corrosion inhibiting properties. While it is convenient for R and R' to be the same hydrocarbyl radical it is sometimes advantageous for R and R' to be different hydrocarbyl groups or to be a mixture of secondary and tertiary hydrocarbyl radicals.
The additives of this invention have a number of advantages in addition to those noted above. The selected asparagines in gasoline are generally resistant to the formation of insoluble calcium soaps, to the formation of lead precipitates in the presence of terne metal and to the formation of emulsions in the presence of water.
The substituted asparagines are prepared by the reaction of maleic anhydride with a suitable amine according to the following reaction steps: ##SPC3##
In general, a mole of a suitable secondary or tertiary hydrocarbyl amine is reacted with maleic anhydride at a moderate temperature preferably dissolved in an organic solvent, such as benzene. Following the initial reaction step, the reaction mixture is cooled to a temperature of about 50°C or below and another mole of the hydrocarbyl amine is added to the reaction mixture. On the completion of this addition, the temperature of the reaction mixture is raised to the reflux temperature of the solvent and the mixture refluxed for an extended period until the reaction is complete. The yield of the substituted asparagine is substantially quantitative.
Examples of substituted asparagines which are effective in the present invention include:
N,N'-di-C 14 -C 15 secondary alkyl asparagine
N,N'-di-C 10 -C 14 secondary alkyl asparagine
N,N'-di-C 15 -C 20 secondary alkyl asparagine
N,N'-di-C 7 -C 9 secondary alkyl asparagine
N-sec.-octyl,N'-sec. lauryl asparagine
N-sec.-nonyl,N'-sec. octadecyl asparagine
N,N'-di-C 12 tertiary alkyl asparagine
N,N'-di-C 18 tertiary alkyl asparagine
N-C 14 -15 sec. alkyl-N'-C 12 tertiary alkyl asparagine
N-C 12 -14 tert. alkyl-N'-C 18 -22 tert. alkyl asparagine
N,N'-di-C 11 -C 14 -sec. alkyl asparagine
The fuel composition of the present invention comprises a mixture of hydrocarbons in the gasoline boiling range containing a minor amount of the substituted hydrocarbyl asparagine. In general, the additive is employed in the fuel composition at a concentration ranging from 0.0005 to 0.1 weight percent with the preferred concentration range being from about 0.002 to 0.02 weight percent. The motor fuel composition of the invention can contain additives conventionally employed in gasoline including anti-knock agents, corrosion inhibitors, anti-oxidants and upper cylinder lubricants. This fuel composition can also contain valve deposit inhibitors such as disclosed in U.S. Pat. No. 3,502,451 and this disclosure is incorporated in the present invention.
The following example illustrates the method of preparing the substituted asparagines of this invention.
EXAMPLE I
To a gently refluxing, stirred solution of 98 g (1.0 mole) maleic anhydride in 200 ml benzene there is slowly added dropwise 220 g (1.0 mole) of the C 14 -C 15 sec.-alkyl amine. After the addition is complete the solution is cooled to 50°C and another 220 g (1.0 mole) of the amine in 200 ml benzene is added dropwise. After this addition is complete the temperature is raised and the solution is refluxed for 5 hours. The solvent is then stripped to afford 535 g of a viscous, amber oil. The yield of the N,N'-di-C 14 -C 15 -secondary alkyl asparagine is quantitative.
Analysis Found Calc. %N 5.5 5.2 TAN 91.2 104 TBN 105 104 n D 20 1.4785
any gasoline suitable for a spark-ignited, internal combustion engine can be used in the practice of this invention. In general, the base fuel will consist of a mixture of hydrocarbons in the gasoline boiling range, i.e., from about 75° to 450°F. The hydrocarbon components can consist of paraffinic, naphthenic, aromatic and olefinic hydrocarbons obtained by thermal or catalytic cracking or reforming of petroleum hydrocarbons. This base fuel will generally have a Research Octane Number above 85 and preferably above 90.
The substituted asparagine additive of the invention was tested for its effectiveness as a carburetor Detergency Test. This test is run on a Chevrolet V-8 engine mounted on a test stand using a modified four barrel carburetor. The two secondary barrels of the carburetor are sealed and the feed to each of the primary barrels arranged so that an additive fuel can be run in one barrel and a base fuel run in the other. The primary carburetor barrels were also modified so that they had removable aluminum inserts in the throttle plate area in order that deposits formed on the inserts in this area would be conveniently weighed.
In the procedure designed to determine the effectiveness of an additive fuel to remove preformed deposits in the carburetor, the engine is run for a period of time usually 24 or 48 hours using the base fuel as the feed to both barrels with engine blow-by circulated to the air inlet of the carburetor. The weight of the deposits on both sleeves is determined and recorded. The engine is then cycled for 24 additional hours with base fuel being fed to one barrel, additive fuel to the other and no blow-by to the carburetor air inlet. The inserts are then removed from the carburetor and weighed to determine the difference between the performance of the additive and non-additive fuels in removing the preformed deposits. After the aluminum inserts are cleaned, they are replaced in the carburetor and the process repeated with the fuels reversed in the carburetor to minimize differences in fuel distribution and barrel construction. The deposit weights in the two runs are averaged and the effectiveness of the base fuel and of the additive fuel for removing deposits expressed in percent.
The base fuel employed in the following examples was a premium grade gasoline having a Research Octane Number of about 100 and containing 3 cc of tetraethyl lead per gallon. This gasoline consisted of about 25% aromatic hydrocarbons, 10% olefinic hydrocarbons and 65% paraffinic hydrocarbons and boiled in the range from about 90°F to 360°F.
The carburetor detergency test results obtained from the base fuel and the additive-containing fuels are set forth in the following Table. The additive-containing fuels contained the active detergent additive at a concentration of 20 PTB (pounds per thousand barrels of fuel), a concentration equal to about 0.01 weight percent.
TABLE I
Chevrolet Carburetor Detergency Test
Deposit Removal
Deposit Deposit Percent Run Build-up Removed effective ,mg* ,mg 1 Base Fuel 32.0 11.2 35 2 Base Fuel + 20 PTB 28.5 26.6 93 N,N'-di-C 14 -C 15 sec. alkyl asparagine * Built up with base fuel.
EXAMPLE II
A Chevrolet Carburetor Detergency Test was conducted employing a gasoline containing N,N'-di-C 12 -tert. alkyl asparagine as the detergent. The base fuel was similar to the base fuel employed in Table I above.
TABLE II
Chevrolet Carburetor Detergency Test
Run Fuel Percent Effective 1 Base Fuel 41 2 Base Fuel + 30 PTB N,N'-di-C 12 -tert. alkyl asparagine* 70 * Conventional non-dispersant gasoline additives also present.
This example illustrates that substituted asparagines, in which the alkyl radicals are tertiary alkyl radicals, are highly effective carburetor detergents.
The action of the substituted asparagines as anti-stalling, anti-icing additives was evaluated in a Glass Tube Carburetor Icing Bench Test consisting of a glass tube containing a simulated throttle plate so that cooled moisture saturated air from an ice tower is drawn through the simple glass tube gasoline carburetor by suction from a vacuum pump. The gasoline sample is placed on a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is usually 20 gauge. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation on the simulated throttle plate. The formation of ice on the throttle plate causes a pressure differential which is registered on a manometer. The fuels were rated in terms of seconds required to attain a pressure differential of 0.9 inch of mercury. Since most fuels stall in an engine in 1 to 4 minutes, 300 seconds is the maximum time taken for a run. A recording of 300 seconds denotes no simulated stall (pressure differential did not reach 0.9 inch of mercury), within the test period. Each fuel is run three times in succession and the average is reported. If the differences in runs are great the glass tube carburetor and test throttle are washed with alcohol and the runs repeated. A leaded winter-grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in about 50 to 90 seconds in this test. Additives which raise the stalling time to over 200 seconds are effective anti-stalling, anti-icing additives.
The following Table gives the carburetor anti-icing results of secondary alkyl asparagine derivatives of the invention in comparison to some ineffective asparagines. The additives were employed at a concentration of 20 PTB (pounds per thousand barrels of fuel).
TABLE III
ANTI-ICING TEST
Seconds to 0.9" Fuel Composition HG Manifold Vacuum 1. Base Fuel 72 2. Base Fuel + N,N'-di-C 10 -C 14 - sec. alkyl asparagine 217 3. Base Fuel + N,N'-di-C 14 -C 15 - sec. alkyl asparagine 248 4. Base Fuel + N,N'-di-C 12 - tert. alkyl asparagine 133 5 Base Fuel + N,N'-di-C 18 -C 22 - tert. alkyl asparagine 74
The rust inhibitng properties of fuel compositions containing secondary alkyl derivatives of the invention was determined in the Colonial Pipeline Rust Test. This test is a modification of ASTM Rust Test D-665-60 Procedure A. In the Colonial Pipeline Rust Test, a steel spindle is polished with non-waterproof fine emery cloth. The spindle is immersed in a mixture containing 300 cc fuel and 30 cc distilled water and is rotated at 100°F for 3.5 hours. The spindle is then rated visually to determine the amount of rust formation. A passing result is an average of less than 5% rust.
The results of this test are set forth in Table IV below. The additives were employed at a concentration of 20 pounds per thousand barrels of fuel.
TABLE IV
Colonial Pipeline Rust Test
Fuel Composition Percent Rust 1. Base Fuel 90, 100 2. N,N'-di-C 10 -C 14 -sec. alkyl asparagine trace, trace 3. N,N'-di-C 14 -C 15 -sec. alkyl asparagine trace, 5-10 4. N,N'-di-C 15 -C 20 -sec. alkyl asparagine trace, 5 5. N,N'-di-C 11 -C 15 -sec. alkyl asparagine 5, 0 6. N,N'-di-C 7 -C 9 -sec. alkyl asparagine 0, 0 7. N,N'-di-C 12 -tert. alkyl asparagine 100, 80 8. N,N'-did-C 18 -C 22 -tert. alkyl asparagine 80, 80
The foregoing test demonstrates the outstanding effectiveness of secondary alkyl derivatives of the invention in their rust inhibiting properties in contrast to related materials which are ineffective in these properties.