US2982634A - Alkenyl succinamic acid deicer - Google Patents

Description

2,982,634 wee M y 2. l

2, 63 ALKENYL SUCCINAMIC ACID DEICER Edwin M. Nygaard, Woodbury, NJ., assignor to Socony Mobil Oil Company, Inc., a corporation of New York g No Drawing. Filed Jan. 27, 1959 Ser. No. 789,269

' 4 Claims. (CI. 44-41 V This invention relates to gasoline compositions adapted to improve the operation ofinternal combustion engines. It is more particularly concerned with motor fuels that provide improved engine operation under cool, humid weather conditions. i

As is well known to those skilled in the art, frequent stalling of automobile engines, especially during, the warmup period, has been a common occurrence. This difliculty is most pronounced in postwar cars having automatic transmissions and a consequent limit on the maximum permissible idle speed, although icingl'occurs in cars not having automatic transmissions. Stallingof this type, of course, is a definite safety'hazard, as well as a decided inconvenience in frequent restarting of'the engine.

It is now recognized that stalling during the warmup period is attributable to the formation of'ice on' the throttle plate and the carburetor barrel near it. The water which forms the ice does not come from the gasoline, i.e., as entrained water, but from the air that enters the carburetor. As has been mentioned hereinbefore, stalling generally occurs in. cool, humid weather,

the throttle plate and in the carburetor barrel. The more moist this air is, the greater the buildup of ice. Then, when the engine is idled, the throttle plate closes and the ice chokes off the normal small flow of air through the small clearance between the throttle plate and the carburetor wall. This causes the engine to stall. The engine can usually be restarted when the heat from the exhaust manifold melts the ice: sufficiently. However, stalling will continue until the'engine is completely warmed up.

Carburetor icing occurs in many vehicles when cruising at speeds of 30-60 m.p.h. Such icing is a pronounced problem in the case of certain trucks and cars equipped with carburetors having Venturi-type fuel-air mixing tubes (emulsion tubes). Suchcarburetors are found in trucks and in many European cars. The ice builds up on the tube and restricts the flow of air, thereby enriching the fuel mixture and reducing efficiency. Eventually the engine may stall.

Gasoline is a mixture of hydrocarbons having an initial boiling point falling'between about 75 F. and about 135 F. and an end-boiling point falling between about 250 F. and about 450 The boiling range of the gasoline,- of course, reflects on its volatility. Thus, a higher boiling gasoline will be less volatile and give less stalling difliculty. It has been proposed in the art that a gasoline having an A.S.T.M. mid-boiling (50%) point of 310 F. or higher will not be subject to stalling.

at i 0551s? alkenyl succinamic acids.

Although this may. be the case for a given series of:

gasolines, however, it isnot the sole and controlling factor.- Gasolines of higher mid-boiling point but a low initial boiling point (e.g. full boiling range gasolines).c an in duce stalling when the aforementioned stall-inducing atmospheric conditions are prevalent. Thus, any gaso line will give difficulty in damp, cool weather. In niod- 5 cm engine operation, however, control of stalling by means of volatility is not feasible, because other performance characteristics are affected.

It has now been found that stalling during engine warmup can be overcome simply and economically. It has been discovered that small amounts of certain alkenyl succinamic acids, when added to motor gasoline, will overcome stalling difficulties attributable to carbue retor icingl. V

Accordingly, it is an object of this invention to provide an improved motor fuel. Another object is to pro vide a motor fuel adapted to prevent stalling during engine warmup in cool, humid weather. A specific object is to provide an antistall gasoline containing certain Other objects and advantages of this invention will become apparent to those skilled in the art, from the following detailed description.

In general, this invention provides a motor gasoline, containing a small amount, sufficient to inhibit stalling, of an alkenyl succinamic acid, having between about 10 and about 25 carbon atoms in the alkenyl radical thereof.

The addition agents contemplated herein are the alkenyl succinamic acids having between about 10 carbon atoms and about 25 carbon atoms in the alkenyl radical. These compounds are readily prepared by reacting an alkenyl succinic acid anhydride in a 1:1 molar ratio with ammonia or with ammonium hydroxide. When reacting the acid anhydride with ammonia, ammonia gas is bubbled through a'solution'of the anhydride in a non-polar solvent, e.g., benzene, toluene, or xylene. Gen: erally, the reaction is carried out by introducing ammonia gas at a slow rate, up to about 126 cc. perminute. The temperaturewill be between about 60 C. and about 85C. In reacting with ammonium hydroxide the acid anhydride is reacted with ammonium hydroxide solution acid. In forming'this ammonium salt, theammoniun'z tively low temperatures, in the order of about 5-30 C.

- U The free succinamic acid is obtained by neutralizing the ammonium salt with a dilute aqueous acid solution, such as hydrochloric acid andsulfuric acid. It is oftenpreferable to carryout the reaction using an organic solvent, such .aspetroleum ether, benzene, xylene, or toluene.

The alkenyl'succinic acid anhydrides are well known materials, many of which are commercially available.

They have the structure:

. 10 carbon atoms and about 25 carbon atoms.

anhydride, andpentaco senyl succinic acid anhydrideax'.

, 2 R-CH-C HrCi 0 I wherein R is an alkenyl radical having between about,

Non-- limiting examples thereof are decenyl succinic acid anhydride, undecenyl succinic acid anhydride, triisobutenyl succinicacid anhydride, tetrapropenyl succinic acid anhydride, dodecenyl succinic acid anhydride, tetrapropenyl succinic acid anhydride, tetradecenyl succinic acid anhydride, hexadec'enyl succinic acid anhydride, tetraiso butenyl succinic acid anhydride, octadecenyl succinic acid anhydride, eicosenyl succinic acid anhydride, henei-' cosenyl succinic acid anhydride, tricosenyl succinic acid The amount of alkenyl succinamic acid that is added to the motor gasoline will vary between about 0.005 percent and about 0.5 percent, by weight, of the gasoline. In preferred practice, amounts varying between about 0.01 percent and about 0.05 percent, by weight, are used.

The antistall additives of the invention may be used in the gasoline along with other antistall addition agents or other additives designed to impart other improved properties thereto. Thus, anti-knock agents, pre-ignition inhibitors, anti-rust agents, metal-deactivators, dyes, antioxidants, detergents, etc., may be present in the gasoline. Also, the gasoline may contain a small amount, from about 0.01 percent to about 1 percent, by weight, of a solvent oil or upperlube. Suitable oils. for example, in elude Coastal and Mid-Continent distillate oils having viscosities within the range of from about 50 to about 500 S.U.S. at 100 F. Synthetic oils, such as diester oils, polyalkylene glycols, silicones, phosphate esters, polypropylenes, polybutylenes and the like, may also be used.

The following examples are for the purpose of illustrating this invention and demonstrating the effectiveness thereof. This invention is not to be limited to the specific compositions set forth in the examples or to the operations and manipulations involved. Other materials and formulations as described hereinbefore can be used, as those skilled in the art will readily understand.

The ability of an additive to inhibit stalling is demonstrated in the following test:

CHEVROLET ENGINE TEST A standard Chevrolet engine, equipped with a Holley single downdraft carburetor, was mounted in a cold" chamber refrigerated to about 40 F. A thermocouple was attached to the throttle plate shaft to record the plate temperature. A /2-inch insulating gasket was placed between the carburetor and manifold to prevent heat conduction. An asbestos sheet covered the entire manifold system to shield the carburetor from convection and radiation. A spray chamber was used to saturate the incoming air with moisture before entering an ice tower which cooled the air to about 35 F.

In conducting a test, the engine was first run for about minutes at 2000 r.p.m. to bring the engine temperature to equilibrium. The engine was then shut off. When the throttle shaft temperature rose to 40 F., the engine was restarted with the idle speed set at 450 r.p.m. so that the base fuel stalled at idle in 10 seconds or less after at run-time of 20 to 50 seconds. Run-time means the time that the engine was run at 2000 r.p.m. before returning to idle.

All the runs were started when the throttle shaft reached 40 F. At the instant of starting, the throttle arm was moved to the 2000 r.p.m. position and a stop watch started. At the end of the selected run-time, the throttle arm was moved to the idle position. The time required to stall was recorded. Several tests were made at each run-time and averaged.

In evaluating an additive, the base fuel was first tested followed by several concentrations of the additive. The system was flushed between tests wifh the fuel to be run next. Any improvement caused by the additive was reflected in a longer run-time (as compared to the base fuel) to cause stalling in 10 seconds or less when the engine was idled. The more effective the additive, the longer the run-time.

HILLMAN-MINX ENGINE TEST A downdraft Solex FAI 3O carburetor was mounted on a standard 1953 Hillman-Minx engine. The engine was connected to a 7.5 horsepower induction motor and operated under load at 2800 r.p.m. This was equivalent to driving at about 40 miles per hour.

The Solex carburetor was especially prone to icing on its spraying well which is located in the center of the carburetor throat. The spraying well is a cylindrical recorded at one minute intervals for 20 minutes.

metal tube with apertures through which a fuel-air mixture is sprayed into the carburetor throat. Evaporation of the fuel refrigerates the spraying well.

As ice formed on the well it restricted the flow of air through the carburetor and caused a drop in pressure. This pressure change was recorded by a monometer connected above and below the point of ice deposition. Temperatures at this point were measured by a thermocouple attached to the well. The entire carburetor was enclosed in an asbestos chamber that was connected to an ice tower. Air at 34-37 F. and 90-100 percent relative humidity was passed through the carburetor at constant velocity.

In conducting a test the engine was first run until the sprayin well reached an equilibrium temperature of about 20-25 F. The fuel flow was then stopped and the engine was driven by the induction motor until the spraying well reached 45 F. (warm ambient air was admitted to the carburetor during this period). Fuel flow was now restored to the engine and the run was started. As the engine operated under load, ice deposited on the spraying well. The pressure drop across the ice formation was The run was concluded. Several tests were made on each fuel blend and the results were averaged. A fuel rating was obtained by using these pressure readings to calculate the percentage of the carburetor throat area that would be blocked with ice after 20 minutes. The percent of annular area in the carburetor that is blocked by ice determines the amount of pressure drop across the annular opening in any given installation. Thus, for each carburetor, the amount of throat area blocked by ice is related to the amount of pressure drop above and below the point of ice deposition. The relationship between pressure drop and area blocked was determined to calibrate the carburetor, as follows:

A series of flanged cylinders were prepared, which fitted over the emulsion tube and blocked a portion of the annular opening. Each tube had a different, but known size flange. Thus, it was known what fraction of the annular area was blocked by each flange. The engine was operated with a flanged cylinder in the carburetor and the amount of pressure drop was noted and recorded. This operation was repeated with each flange.

From the data, thus obtained, the relationship between pressure drop and amount of throat area blocked was plotted. Then, when runs were made using blank fuel or inhibited (test) fuel, but with no flanged inserts in the carburetor, the throat area blocked by ice was determined from the amount of pressure drop. The area blocked after the 20-minute run is obtained from the summation of the one-minute observations.

It will be appreciated, of course, that calibration curves will vary with each carburetor, but any carburetor can be readily calibrated as aforedescribed. As is the case in many test procedures, results can vary from time to time, because of slight variations in test conditions, vapor pressure of fuel, and even techniques of individual operators. Thus, each day a test run is made, a blank fuel should be run. This provides a reference point, so that even if values determined may not be finite, comparison of a test fuel result with the result on the blank fuel gives a positive order of magnitude, i.e., one can say for example that an additive cut the amount of ice formation by some certain percentage.

Three base gasolines were used to evaluate the antistall additives. Gasoline A" was a blend, by volume, of 66 percent catalytically cracked gasoline, 6 percent natural gasoline, 12 percent benzene, 8 percent toluene, and 8 percent butane. It had an A.S.T.M. boiling range of 87 F. to 385 R, with a mid-boiling point of 197 F. Gasoline B was a blend, by volume, of 66 percent catalytically cracked gasoline, 2 percent natural gasoline, 12 percent benzene, 8 percent toluene, and 12 percent butane. It had an A.S.T.M. boiling range of F. to

394 F., with a mid-boiling point of 200 F. "Gasoline C had the same composition as Gasoline A, but had an A.S.T.M. boiling range of 85 F. to 402 F., with a midboiling point of 198 F.

Example 1 Into a reaction vessel equipped with a thermometer, condenser, dropping funnel, and agitator, were placed 53.2 grams (0.2 mole) of tetrapropenyl succinic acid anhydride. Agitation was commenced and the contents of the vessel were cooled to 6 C. Then, 28.0 grams (0.8 mole) of ammonium hydroxide was added over a period of 45 minutes. During this period of time, the temperature in the reaction vessel 'was between about 6 C. and about 26 C.

Then, the thick mass of material (ammonium tetrapropenylsuccinamate) in the flask was diluted with 50 cc. distilled water and cooled to 2 C. Thereupon a gradual addition of 73 cc. of 20% HCl was begun. The material in the reaction vessel formed a clear aqueous layer and a very viscous layer of organic material. An additional 50 cc. of water and petroleum ether to dissolve the organic matter were added and the addition of HCl was completed. The aqueous phase at this point had a pH of 3. The material was transferred to a separatory funnel and agitated. The organic layer was separated and filtered. The petroleum ether was distilled out at atmospheric pressure and, finally, under 142 mm. mercury pressure at 5062.5 C. The product was a very viscous, amber-color fluid, tetrapropenyl succinamic acid.

Example 2 Into a reaction vessel provided with an agitator, theta mometer, gas inlet tube, and a condenser having a water take-oft trap, were placed 105.2 grams (0.25 mole) of ll-tricosenyl succinic acid anhydride and 500 grams xylene. The contents of the vessel were dried by azeotropic distillation (0.1 cc. water removed). The water take-01f was replaced with a reflux condenser protected with a drying tube containing solid desiccant. Gradually, over 2.75 hours, 3.75 grams of dry ammonia gas was introduced into the reaction mixture and the temperature was slowly raised to 80 C. Then, another 5.2 grams of ammonia gas was introduced at this temperature. The xylene was removed by distillation under reduced pressure leaving the product, ll-tricosenyl suc-. cinamic acid,

CmHnCH=CH-CHCH21 H CH:

Blends of tetrapropenyl succinamic acid (Example 1) in two concentrations in gasoline I A werev prepared. These blends were subjected to the Chevrolet engine test. Pertinent data are set forth in Table I.

TABLE I Run Time to Additive Conc'n, WT Percent Gasoline 10 Sec. Stall 7 Time (See) Blank A 50 0.01 A 80 0.02 A 80 were also blended in gasolines B and Cand further tested on the Hillman-Minx engine test." Pertinent data and 8 results are set forth in Table II.

TABLE II Percent Additive of Example Conen, Wt. Gasoline Annular Area Percent Blocked With Ice 1 0.0 (blank) 0 38 1 0 01- C 3. 6

O 9 B 36 B 21 B 16 B 34 B 15 1. A motor gasoline containing a small amount, sufli-' cient to inhibit stalling, of an alkenyl succinamic acid, having between about 10 and about 25 carbon atoms in the alkenyl radical thereof, and being otherwise unsulr stituted.

2. A motor gasoline containing between about 0.005

percent and about 0.5 percent, by weight, of an alkenyl succinamic acid, having between about 10 and about 25 carbon atoms in the alkenyl radical thereof, and being otherwise unsubstituted.

3. A motor gasoline containing between about 0.01

percent and about 0.05 percent, by weight, of tetrapro- V i penyl succinamic acid.

4. A motor gasoline containing between about 0.01

percent and about 0.05 percent, by weight, of 11#tri-' cosenyl succinamic acid.

References Cited in the file of this patent I UNITED STATES PATENTS 2,604,451 Rocchini Iuly 22, 1952' 2,706,677 Duncan et al Apr. 19, 1955 2,843,464 Gaston et al. 'July 15, 1958 r 2,862,800 Cantrell et al. Dec. 2, 1958 a 2,886,423 Vitalis et al. May' 12, 1959 2,906,613 Mills Sept. 29, 19 59 8' OTHER REFERENCES 7 Petroleum Refining with Chemicals, Kalichevsky and Kobe, Elsevier Pub. Co., 1956, page 480.

UMTLU STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,982,634 May 2, 1961 Edwin M. Nygaard 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 5, lines 48 to'53, the formula should appear as shown below instead of as in the patent:

Signed and sealed this 6th day of February 1962.

(SEAL) Attest:

DAVID L. LADD ERNEST w. SWIDER Attesting Officer Commissioner of Patents

Claims (1)

1. MOTOR GASOLINE CONTAINING A SMALL AMOUNT, SUFFICIENT TO INHIBIT STALLING, OF AN ALKENYL SUCCINAMIC ACID, HAVING BETWEEN ABOUT 10 AND ABOUT 25 CARBON ATOMS IN THE ALKENYL RADICAL THEREOF, AND BEING OTHERWISE UNSUBSTITUTED.