GB2047237A - Primary aliphatic hydrocarbon amino alkylene-substituted asparagine and a motor fuel composition containing same - Google Patents

Abstract

The invention provides a primary aliphatic hydrocarbon amino alkylene-substituted asparagine having the formula: <IMAGE> in which R is a primary aliphatic hydrocarbon radical having from 6 to 30 carbon atoms, R' is hydrogen or methyl radical. These compounds can be employed in motor fuel compositions as anti-corrosion additives alone or mixed with N-alkyl alkylene diamines of the formula R,R'-N-C3H6-NH2 wherein R and R' have the meanings given above.

Description

SPECIFICATION Primary aliphatic hydrocarbon amino alkylenesubstituted asparagine and a motor fuel composition containing same This invention relates to novel primary aliphatic hydrocarbon amino alkylene-substituted asparagines, and motor fuel compositions containing these compounds.

Gasoline compositions are highly refined products. Despite this, they contain minor amounts of impurities which can promote corrosion while the fuel is transported in bulk or held in storage. Corrosion can also occur in the fuel tank, fuel lines and carburetor of a motor vehicle. As a result, a commercial motor fuel composition must contain a corrosion inhibitor to inhibit or prevent corrosion.

Internal combustion engine design is undergoing changes to meet new standards for engine exhaust gas emissions. One design change involves the feeding of blow-by gases from the crankcase zone of the engine into the intake air supply to the carburetor, rather than venting these gases to the atmosphere as in the past. Another change involves recycling part of the exhaust gases to the com bustion zone of the engine, in order to minimize objectionable emissions. Both the blow-by gases from the crankcase zone and the re-cycled exhaust gases contain significant amounts of deposit-forming substances, which promote the formation of 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 over-rich fuel mixture results. This condition produces rough engine idling or stalling, causing an increase in the amount of polluting exhaust gas emissions, which the engine design changes were intended to overcome, and decreasing fuel efficiency.

Certain N - alkyl - alkylene diamine compounds, e.g. N - oleyl -1,3 - diaminopropane, are known to give carburetor detergency properties to gasoline.

These additives, however, do not impart corrosioninhibiting properties to gasoline. As a result, a motor fuel containing an N - alkyl - alkylene diamine must be modified or formulated with an additional additive in order to have the necessary corrosioninhibiting properties for marketability.

U.S. Patent No. 3,773,479 discloses a motor fuel composition containing an alkyl-substituted asparagine having the formula:

in which R and R' each represents a secondary or tertiary alkyl radical from 7 to 20 carbon atoms. The corresponding compounds in which R and R' are straight chain radicals are too insoluble in gasoline to be effective as an additive.

A copending application disclosing a motor fuel composition containing the reaction product of an aliphatic ether monoamine and maleic anhydride was filed on March 27, 1978 under Serial No.

890,104.

This invention provides novel primary aliphatic hydrocarbon amino - alkylene - substituted asparagine compounds which are useful as multifunctional additives when employed in a liquid hydrocarbon fuel for an internal combustion engine.

These compounds, which are produced by reacting about two moles of an N-primary alkyl-alkylene diamine with a mole of maleic an hydride to produce compounds having a plurality of amino groups in an essentially straight chain primary alkylhydrocarbon radical, exhibit surprising corrosion-inhibiting properties as well as essential carburetor detergency properties, when employed in gasoline. This finding of multifunctionality is surprising in itself and also contrasts with the disclosure in U.S. Patent No.

3,773,479 that there is selectivity in the effectiveness of derivatives of maleic anhydride.

The fuel compositions of the invention prevent or reduce corrosion problems during the transportation, storage and the final use of the product. The fuel compositions of the invention also have highly effective carburetor detergency properties. When such a fuel composition is employed in a carburetor which already has a substantial build-up of deposits from prior operations, a severe test of the carburetor detergency property of a fuel composition, this motor fuel is effective for removing substantial amounts of the preformed deposits.

The present invention provides an asparagine compound having the formula:

wherein R is a primary aliphatic hydrocarbon radical having from 6 to 30 carbon atoms and R' is hydrogen or methyl.

The present invention also provides a motor fuel composition which comprises a mixture of hydrocarbons in the gasoline boiling range, and from 0.0002 to 0.2 weight percent of an asparagine compound as defined above.

According to a further embodiment, the present invention also provides a motor fuel composition which comprises a mixture of hydrocarbons in the gasoline boiling range and from 0.001 to 0.003 weight percent of an additive composition comprising A) from 30 to 70 weight percent of an asparagine compound as defined above, and B) from 70 to 30 weight percent of an Nalkyl-alkylene diamine component having the formula: R,R'-N-C3H6-NH2 wherein R and R' have the meanings given above.

Generally preferred additive compositions contain approximately equal weights of the asparagine compound (A) and the N-alkyl alkylene diamine component (B).

A preferred compound ofthe invention is one in which R is a straight chain primary aliphatic hydrocarbon radical and R' is hydrogen.

The preferred compound has the formula:

in which R is a primary aliphatic hydrocarbon radical having from 16 to 20 carbon atoms.

The novel compounds of the invention are prepared by reacting an N - primary - alkyl - alkylene diamine with maleic anhydride. Approximately two moles of the N-primary alkyl-alkylene diamine are reacted with one mole of maleic anhydride at a temperature from room temperature to 110"C. preferablyfrom 600 to 100"C. The upper temperature limit in the preparation of the additive is critical.

Higher temperatures, especially above 11 0 C., cause the formation of succinimide compounds which have essentially no corrosion inhibiting properties fora motor fuel composition.

The N-primary alkyl-alkylene diamine reactant has the formula: R, R'-N-C3H6-NH2 in which R is a primary aliphatic hydrocarbon radical having from 6 to 30 carbon atoms and R' is hydrogen or methyl. Preferred N-primary alkyl-alkylene diamines are those in which R is a straight chain primary alkyl radical and R' is hydrogen. As employed herein the term N - alkyl - alkylene diamine covers both N - monoalkyl - alkylene diamine and the N - dialkyl - alkylene diamine structure when R' is methyl.

The most preferred N - alkyl - alkylene diamines have the formula: R-NH-CH2CH2-CH2-NH2 in which R is a straight chain primary alkyl aliphatic hydrocarbon radical having from 16 to 20 carbon atoms.

Examples of suitable N - alkyl - alkylene diamines include N - oleyl -1,3 - propane diamine, N - lauryl 1,3 - propane diamine, N - stearyl -1,3 - propane diamine and N - dodecyl -1,3 - propane diamine.

This reaction is illustrated by the following equation:

in which R and R' have the meanings given above.

Examples of specific compounds of the invention produced in this reaction which are effective as multifunctional gasoline additives include: N,N' - di- (3 - n - oleylamino -1 - propyl) asparagine, N,N'- di -(3- n - dodecylamino - 1 - propyl) asparagine, N,N' -di - (3- n - octylamino - 1 - propyl) asparagine, N,Nr - d- (3 - stearylamino -1 - propyl) asparagine, N,N - dii-(3 - decylamino - 1 - propyl) asparagine, i; N,N'di-(3 - laurylamino - 1 - propyl) asparagine, and N,N' - di- (3 -behenylamino - 1 - propyl) asparagine.

It will be appreciated that by-products andlor impurities can be co-produced along with the compound of the invention in this reaction. The desired additive compounds can be readily recovered from the reaction product by known methods. However, it is feasible and economical to employ the prescribed compounds as produced without separation or purification.

The following preparative examples illustrate methods for preparing the additives of the invention: EXAMPLE I 63.4 grams of maleic an hydride (0.647 mole) are suspended in 423.4 grams of mineral oil having a viscosity of 100 SUS at 100"F, and is heated at 100"C.

for 1 hourwith stirring and nitrogen purge. N - oleyl 1,3 - propane diamine, (460 grams, 1.347 mole) in 100 grams of mineral oil similartothe above is introduced at 100"C. over 1 hour. The reaction is heated at 100"C. for an additional 2 hours and then filtered hot.

Analysis of the 50 percent oil solution of the additive was as follows: N, wt. % 3.5 Total Acid Number (TAN) 27.4 Total Base Number (TBN) 106.5 EXAMPLE Il 63.4 grams (0.647 moles) of maleic an hydride were added to 480 milliliters of xylene and heated to about 1 OO"C. 460 grams (1.349 moles) of N - oleyl 1,3 - propane diamine were added to the xylene solution of the maleic anhydride. The resulting mixture was continuously heated at about 100"C. for 2 hours It was then cooled to room temperature and stripped free ofxytene. A yield of 540 grams or 99 percent was obtained having the following analysis: : TBN 239 TAN 56 %N 6.2 EXAMPLE 111 13.2 grams (0.137 moles) of maleic anhydride anhydride were suspended in 50 grams of mineral oil in a closed reactor. The reactor was purged with nitrogen and the mixture was stirred with heating at 100"C. for 1 hour. 50 grams (0.269 moles) of N I(n-octyl)-1,3-propane diamine in 13.2 grams of mineral oil were introduced into the maleic anhyd ride mixture at 1000C. over a 1 hour period. The reac tion mixture was heated at 100"C. for an additional 2 hours and then filtered hot.

Analysis of the oil solution of the additive was as follows: N,wt.% 5.1 EXAMPLE IV 49 grams (0.51 moles) of maleic anhydride were suspended in 165.3 grams of mineral oil. The reactor was purged with nitrogen and the mixture was stir red with heating at 100"C. for 1 hour. 136.3 grams of N-1 (sec. C14-C,6 alkyl)-1,3-propane diamine were mixed with 20 grams of mineral oil. This solution was introduced into the maleic anhydride solution at 100"C. over a 1 hour period. The reaction mixture was heated 100"C. for an additional 1 hour and then the reaction product was filtered hot.

Analysis of the oil solution of the additive was as follows: N, wt % 2.2 In another embodiment of the invention, the additive is a composition whose second component is an N-primary alkyl-alkylene diamine having the formula: R,R'-N-C3H6-N H2 in which R is a primary aliphatic hydrocarbon radical having from 6 to 30 carbon atoms and R' is hydrogen or methyl. Preferred N-primary alkyl-alkylene diamines are those in which R is a straight chain primary alkyl radical and R' is hydrogen. As employed herein the term N - alkyl - alkylene diamine covers both N - monoalkyl - alkylene diamine and the N-dialkyl-alkylene diamine structure when R' is methyl.

The most preferred N - alkyl - alkylene diamine additive has the formula: R-NH-CH2CH2CH2-NH2 in which R is a straight chain primary alkyl aliphatic hydrocarbon radical having from 16 to 20 carbon atoms.

Examples of suitable N-alkyl-alkylene diamine additives which can be beneficially employed in combination with the prescribed substituted asparagine include N - oleyl - 1,3 - propane diamine, N - lauryl - 1,3 - propane diamine, N - stearyl - 1,3 propane diamine and N - dodecyl - 1,3 - propane diamine.

The base fuel, which is used in the compositions of the invention, is a mixture of hydrocarbons boiling in the gasoline boiling range. This base fuel may con sistofstraight-chain or branched-chain paraffins, cycloparaffins, olefins, and aromatic hydrocarbons, and any mixture of these. The base fuel can be derived from straight-run naphthia, polymer gasoline, natural gasoline or from catalytically reformed stocks, and generally boils in the range from 80" to 4500F. (25 to 2350C). The composition and the octane level of the base fuel are not critical, and any conventional motor fuel base can be employed in the practice of this invention.

In general, when the asparagine compound is used by itself, it is added to the base fuel in a minor amount, i.e., an amount effective to provide both corrosion inhibition and carburetor detergency to the fuel composition. It is effective in an amount ranging from 0.0002 to 0.2 weight percent based on the total fuel composition. An amount of the asparagine compound ranging from 0.001 to 0.01 weight percent is preferred, with an amount from 0.001 to 0.003 being particularly preferred, the latter amounts corresponding to 3 to 8 PTB (pounds of additive per 1000 barrels of gasoline) respectively.

The additive composition comprising the asparagine compound and the N-alkyl alkylene diamine compound is employed in motor fuel compositions according to the invention in a concentration ranging from about 0.001 to 0.003 weight percent, based on the weight of the motorfuelcomposi- tion. It is preferred to employ the additive composition in a concentration ranging from 0.0015 to 0.0025 weight percent, with the most preferred concentration being about 0.002 weight percent, or a dosage equivalent to about 6 PTB (6 pounds of additive per 1000 barrels of gasoline).

The fuel composition of the invention may contain any of the additives normally employed in a motor fuel. For example, the base fuel may be blended with an anti-knock compound, such as a methylcyclopentadienyl manganese tricarbonyl or tetraalkyl lead compound, e.g. tetraethyl lead, tetramethyl lead ortetrabutyl lead, and chemical and physical mixtures thereof, generally in a concentration from 0.025 to 4.0 cc. per gallon of gasoline. The tetraethyl lead mixture commercially available for automotive use contains an ethylene chloride-ethylene bromide mixture as a scavenger for removing lead from the combustion chamber in the form of a volatile lead halide.

Gasoline blends were prepared from a typical base fuel mixed with specified amounts of the prescribed fuel additive of the invention. These fuels were then tested to determine the effectiveness of the additive in gasoline together with comparison fuels in the following performance tests.

The base fuel employed with the additive of the invention in the following examples was an unleaded grade gasoline having a Research Octane Number of about 93. This gasoline consisted of about 32 percent aromatic hydrocarbons, 8 percent olefinic hydrocarbons and 60 percent paraffinic hydrocarbons and boiled in the range from 88"F. to 373"F. (31 to 1900C).

The rust inhibiting properties of fuel compositions of the invention was determined in the NACE Test (National Associatinn of Corrosion Engineers) which is a modification of ASTM Rust Test D-665-60 Procedure A. In the NACE Test, a steel spindle is polished with non-waterproof fine emery cloth. The spindle is immersed in a mixture containing 300 cc of fuel and 30 cc of distilled water and is rotated at 1 OO"F.

(37.8"C) 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 I below: TABLE! NACE RUST TEST Concentration, Percent Run Additive PTB1 Rust 1 N-oleyl-1 .3-propane 2.5 50-100 diamine 2 " 5.0 50-100 3 " 10.0 50-100 4 Example I (in a 50% 5.0 1-5 oil solution) 5 Exampie I (in a 50 /O 10.0 1-5 oil solution) 6 " 20.0 Trace to 7 Example IV (in a 50% 10.0 50-100 oil solution) 8 Commercial Rust 2.5 50-100 Inhibitor 9 " 5.0 1-5 (1) PTB = pounds of additive per 1000 barrels of fuel (unleaded gasoline).

The foreging data show that the novel reaction product of the invention was highly effective as a corrosion inhibitor in the NACE Test, even at the lowest concentrations. This result is in marked contrastto the results obtained using Noleyl-1,3-propane diamine and are superior to the results obtained using a commercial rust inhibitor.

The additive of the invention was tested as a carburetor detergent in the Chevrolet 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 is arranged so that an additive fuel can be run in one barrel and the 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 could 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 24to 48 hours using the base fuel as the feed to both barrels with engine blow-by circulated to an inlet in the carburetor body. The weight of the deposits on both sleeves is determined and recorded. The engine is then cycled for 24 additional hours with a suitable reference fuel being fed to one barrel, additive fuel to the other and blow-by to the inlet in the carburetor body. The inserts are then removed from the carburetor and weighed to determine the difference between the performance of the additive and reference fuels in removing the preformed deposits.Afterthe aluminum inserts are cleaned, they are replaced in the carburetor and the process is 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 fuel composition of the invention is compared to the reference fuel which contains an effective detergent additive. The difference in effectiveness is expressed in percent.

The carburetor detergency test results obtained with the fuel composition of the invention in comparison to the base fuel and to two commercial detergent fuel compositions was obtained at the same detergent additive concentration, i.e. 20 PTB.

The comparison commercial fuels are identified as Reference Fuel A and Reference Fuel B. The results are set forth in the table below.

TABLE II CHEVROLET CARBURETOR DETERGENCY TEST % Wash Down (RemovalJ of Run Additive Fuel Composition Preformed Deposits {1) 1 Base Fuel +1(Y2) 2 Reference Fuel A -62 3 Reference Fuel B -66 4 Base Fuel + 20 PTB Ex. l -80 (Check -86) (1) Built up with base fuel.

PTB = Pounds of Additive per 100 Barrels of fuel based upon 100% active material (additive neat).

(2) "+" Denotes a deposit build-up.

The foregoing tests show that the fuel composi tion of the invention was highly effective in the Chevrolet Carburetor Detergency Test with results superior to two commercial detergent fuel composi tions.

The effect on carburetor detergency of the fuel compositions of the invention was also determined in a second carburetor detergency test, namely, the Buick Carburetor Detergency Test. This test is run on a Buick 350 cubic inch displacement V-8 engine equipped with a two barrel carburetor. The engine is mounted on a test stand and has operating EGR and PCV systems. The test cycle, shown in Table II, is representative of normal road operation. Approximately 300 gallons of fuel and three quarts of oil are required for each run.

Prior to each run the carburetor is completely reconditioned. Upon completion of the run the throttle plate deposits are visually rated according to a CRC Varnish rating scale (Throttle Plate Merit Rating) where 1 describes heavy deposits on the throttle plate and 10 a completely clean plate.

TABLE III 1973 BUICK CARBURETOR DETERGENCY TEST OPERATING CONDITIONS Stage I Stage II Stage III Duration, hours 1 3 1 Speed, r.p.m. 650+25 1500i25 2000i25 Torque, ft.-lbs. 0 80+2 108t2 Water Out, 7. 205+5 205+5 205+5 CarburetorAir, F. 140+5 140+5 140+5 Exhaust Back Pres. - 0.7+0.1 in Hg Man. Vac. In. Hg - 15.8 14.2 Fuel Flow, Ibs/hr 0.7 7.5 12.0 Test Duration, 120 hours The Base Fuel employed for testing the additive of the invention was the same unleaded gasoline composition disclosed above.The results of this test are set forth in the following Table: TABLE IV BUICK CARBURETOR DETERGENCY TEST Additive Carburetor Rating Fuel Concentration PlateslBelow Platesl Run Composition PTB Average 1 Base Fuel -- 2.413.91(3.2) 2 Reference Fuel A(3) 20 6.8/7.5/(7.2) ck 7.817.81(7.8) 3 Reference Fuel Bt" 7.5 5.015.31(5.2) 4 Base Fuel + 15(2) 9.3/9.1 (9.2) Ex. I ,, 8.9/8.7 (8.8) " 9.1/8.9 (9.0) (1) Contains 7.5 PTB of a commercial fuel detergent (2) Concentration based on a 50 percent oil solution of the additive.

(3) An effective carburetor detergent.

The foregoing results demonstrate that the novel fuel composition ofthe invention was unusually effective for maintaining cleanliness of the throttle plates as measured by the CRC Varnish rating scale in the Buick Carburetor Detergency Test.

The following Examples V to IX illustrate two component additive compositions of the invention.

EXAMPLE V An additive is prepared by mixing N,N' - di - (3 - n oleylamino - 1 - propyl) asparagine with N - oleyl 1,3 - propane diamine in 50-50 weight percent amounts, based on diluent free materials.

EXAMPLE Vl An additive is prepared by mixing N,N' - di - (3 lauryl amino - 1 - propyl) asparagine with N - oleyl 1,3 - propane diamine in 50-50 weight percent amounts based on diluent free materials.

EXAMPLE VII An additive is prepared by mixing N,N' - di - (3 dodecyl - amino - 1 - propyl) asparagine with N stearyl - 1,3 - propane diamine in 50-50 weight percent amounts, based on diluent free materials.

EXAMPLE Vffl An additive is prepared by mixing 70 weight percent of N,N' - di - (3 - n - oleylamino - 1 - propyl) asparagine and 30 weight percent of N - oleyl - 13 pro pane diamine, based on the total additive composition of diluent free materials.

EXAMPLE IX An additive is prepared by mixing 30 weight percent of N,N' - di - (3 - decylamino - 1 - propyl) asparagine and 70 weight percent of N - lauryl - 1,3 propane diamine, based on the total additive composition of diluent free materials.

The results obtained using such compositions in the 1973 Buick Carburetor Detergency Test are shown in Table IV below.

TABLE IT BUICK CARBURETOR DETERGENCY TEST Carburetor Fuel Additive Rating Run Composition Concentration (Average) 1 Base Fuel None 3.6 2 Base Fuel 6 PTBct) CompA2) 7.7 3 Base Fuel 6 PTB Comp. B 8.5 4 Base Fuel 6 PTB Example \ 9.3 5 Comparison Fuel A4 - 6.2 6 Comparison Fuel B)4) - 5.8 (1) PTB = pounds of additive per 1000 barrelsoffuel (2) Component A is N,N' - di - (3 - n - oleylamino - 1 - propyl) asparagine (3) Component B is N - oleyl - 1,3 - propane diamine (4) Commercial unleaded detergent gasoline.

Similar results were obtained with the compositions of Examples VI to IX.

SET A

Claims (16)

1. An asparagine compound having the formula:

wherein R is a primary aliphatic hydrocarbon radical having from 6 to 30 carbon atoms and R' is hydrogen or methyl.

2. An asparagine compound having the formula:

wherein R is a straight chain primary aliphatic hydrocarbon radical having from 16 to 20 carbon atoms.

3. N,N' - di - (3 - n - oleylamino - 1 - propyl) asparagine.

4. N,N' - di - (3 - n - dodecylamino - 1 - propyl) asparagine.

5. N,N' - di - (3 - n -octylamino - 1 - propyl) asparagine.

6. N,N' - di - (3- stearylamino -1 - propyl) asparagine.

7. N,N'- di - (3 - decylamino - 1 - propyl) asparagine.

8. N,N' - di - (3 - larylamino -1 - propyl) asparagine.

9. N,N' - di - (3 - behenylamino -1 - propyl) asparagine.

10. A motor fuel composition which comprises a mixture of hydrocarbons in the gasoline boiling range and from 0.0002 to 0.2 weight percent of an asparagine compound as claimed in any of Claims 1 to9.

11. A motor fuel composition as claimed in Claim 10 which contains from 0.001 to 0.01 weight percent ofthe asparagine compound.

12. A motor fuel composition which comprises a mixture of hydrocarbons in the gasoline boiling range and from 0.001 to 0.003 weight percent of an additive composition comprising: A) from 30 to 70 weight percent of an asparagine compound as claimed in any of Claims 1 to 9, and B) from 70 to 30 weight percent of an N - alkyl alkylene diamine component having the formula: R,R'-N-C3H6-NH2 wherein R and R' have the meanings given in Claim 1.

13. A motor fuel composition as claimed in Claim 12 wherein component B is N - oleyl - 1,3 - propane diamine or N - stearyl - 1,3 - propane diamine.

14. A motor fuel composition as claimed in Claim 12 or 13 which contains from 0.0015 to 0.0025 weight percent of the additive composition.

15. A motor fuel composition as claimed in Claim 10 and substantially as hereinbefore defined.

16. A motor fuel composition as claimed in Claim 12 and substantially as hereinbefore described.