US3203971A - Glycol borate amine salts - Google Patents

Description

United States Patent 1 Claim. Cl. 260-462) This application is a divisional of application Serial No. 90,650, filed February 21, 1961, and now US. Patent 3,133,800, issued May 19, 1964.

This invention relates to organic boron compounds as fuel additives and to motor fuels containing organic boron compounds. More particularly, the invention relates to motor fuel compositions containing minor quantities of a multi-functional additive in the form of a glycol borate amine compound, and to such compounds as fuel additives.

In United States Patent 2,497,521 to Charles G. Trautman, there is described and claimed hydrocarbon oil compositions containing minor amounts of an addition agent to improve the stability of the oil. The additive described in the Trautman patent is an amine salt of a boro-diol complex, and is prepared by reacting a molar excess of a 1:2 (molar) boro-alkylene glycol with an amine.

In accordance with the present invention, it has surprisingly been found that the reaction product of a 1:1 (molar) glycol borate with a stoichiometric amount of an amine, acts as a multi-functional additive for motor fuels. The addition of minor amounts of the reaction product to motor fuels imparts bactericidal and anti-rust properties to the fuel, inhibits the buildup of deposits in the carburetor, prevents carburetor icing, and modifies the action of the fuel on the engine to provide an overall improvement in smoothness of engine operation.

It is therefore an object of this invention to provide motor fuels having excellent bactericidal and antirust properties.

Another object is to provide a motor fuel which, in normal consumption, prevents carburetor icing and inhibits the buildup of deposits on carburetor internals.

A further object is to improve smoothness of operation by modifying the action of a fuel on an internal combustion engine.

Other objects and advantages will become apparent from the following detailed description of the invention.

The boron additives of the present invention are believed to have the following formula:

0 I R 1; OHNgR \O R!!! where R is a divalent alpha or beta, straight or branch chain saturated hydrocarbon radical having from 3 to 20 carbon atoms; and R, R and R' are selected from the group consisting of hydrogen or alkyl, alkenyl, amino alkyl and amino-alkenyl groups having from 3 to 20 carbon atoms, provided at least one of the R, R" or R is an alkyl or alkenyl group and not more than one of R, R", or R is an amino alkyl or an aminoalkenyl group. While compounds having R, R, R" and/or R'" groups of more than 20 carbon atoms are suitable for use according to this invention, it vw'll be recognized that the low percent weight of boron in such higher molecular Weight compounds is a disadvantage. Furthermore, the higher molecular weight starting materials required to 3,203,971 Patented Aug. 31, 1965 ice produce such compounds are not readily available and are therefore expensive.

The present invention, however, is in no way limited by any theory concerning the structure of the glycol borate amine compounds.

Physical evidence in the form of calorimetric measurements indicates that a stoichiometric reaction takes place. A definite amount of heat is evolved, indicating a chemical reaction. A maximum of about 2 kilogram calories of heat per mole is evolved when a glycol borate and an amine are mixed. This indicates the formation of a relatively weak chemical bond when compared with the 13 kilogram calories per mole associated with the formation of a polar bond such as HOH. These findings were helpful in interpreting infrared analyses. The reaction product showed all the infra-red bands produced by the glycol borate and four new bands. These new bands were determined not to be solvent bands and did not make an appearance When a solution of glycol borate was examined. These new bands would indicate either (1), the presence of two starting materials plus a third compound, or (2), if one compound is indicated by physical evidence, the formation of a compound between the glycol borate and the amine with force loose enough not to disturb OH and NH vibrations. Since the physical evidence shows the stoichiometric formation of a compound, it would seem that alternative (2) is the proper interpretation of the infra-red analysis.

The organic boron compounds contemplated are those derived from the reaction of a 1:1 (molar) glycol borate having the formula:

and a primary, secondary, or tertiary monoor diamine, having the formula:

RI N R where R, R, R", and R are defined the same as above. To satisfy solubility requirements in gasoline, the reaction product must contain a minimum total of 14 carbon atoms; the glycol portion thereof, a minimum total of 3 carbon atoms. Both alpha and beta glycols are contemplated. The maximum number of carbon atoms is limited by economic factors and to some extent by the effect in the engine; to these ends, a maximum of 30 carbon atoms is recommended.

Motor fuels containing a glycol borate amine compound of the type described are effective in markedly reducing many of the adverse effects resulting from combustion chamber deposits which accumulate during the operation of an initially clean internal combustion engine running on a hydrocarbon fuel, and particularly a hydrocarbon fuel which contains a tetra-alkyl lead compound as an anti-knock agent. Despite the fact that one or more organic halides may be included in the fuel with the tetraalkyl lead, as a scavenging agent, not all of the lead is removed. The adverse effect of residual deposits manifests itself in uncontrolled ignition and a general lack of smoothness in engine operation, caused principally by such deposit becoming heated to incandescence within the combustion chamber during engine operation, and igniting the fuel either before or after that portion of the cycle where normal spark plug discharge would cause ignition. It has been found that incorporating minor amounts of the compounds of this invention in gasoline modifies the action of the resulting fuel on an engine to provide an overall improvement in smoothness of engine operation.

Another prevalent operational difliculty alleviated by the motor fuels of thi invention is carburetor icing. Vapon'zation of gasoline injected into a carburetor absorbs heat from incoming air and adjacent carburetor parts. On cool, humid days the temperature of the incoming air can be reduced below its dewpoint, resulting in condensation of moisture on cooled carburetor parts, which parts in turn have been reduced in temperature to below the freezing point of Water. In a short period of time, suflicient ice can build up on carburetor walls, throttle valves and in the venturi to cause the engine to stall. This condition is most likely to occur when the engine is below its normal operating temperature, as for instance, during warm-up. It has been found that where higher molecular weight amines (about C and above) are reacted in the manner disclosed, and a minor amount Of the reaction product is added to gasoline, the resulting fuel, as normally consumed in an engine, prevents carburetor icing.

Fuels containing compounds formed from higher molecular amines, (about C and above), are also etfective in preventing the formation of carburetor deposits. Such deposits are believed to accumulate from contaminants borne by the copious quantities of intake air an operating carburetor breathes. The situation is aggravated by prolonged engine operation in urban and industrial areas where the concentration of contaminants in the air is high. Since these deposits can result in rough idling and frequent stalling, their inhibition is distinctly advantageous.

The fuels of this invention also possess antirust and bactericidal activity. Bacteria and rust contaminated fuels are believed to be the cause of unpleasant odors and may even accelerate fuel degradation. Suflicient rust and bacteria develop under normal fuel storage conditions to be troublesome, making their elimination highly desirable. The compounds of this invention depress the formation of rust and bacteria to below troublesome levels.

Specific additives which may be used according to this invention include:

Propylene glycol borate dihexyl amine Propylene glycol borate di-Z-ethyl hexyl amine Butylene glycol borate diamyl amine Butylene glycol borate decyl amine Neopentyl glycol borate diamyl amine Hexylene glycol borate tripropyl amine Hexylene glycol borate dibutyl amine Hexylene glycol borate octyl amine Hexylene glycol borate coconut oil amine Hexylene glycol borate oleyl amine The additives so listed are prepared from a 1:1 (molar) glycol borate containing 3 to 6 carbon atoms and an amine selected from the group consisting of primary, secondary and tertiary alkyl amines wherein the alkyl contains from 3 to 18 carbon atoms, and coconut oil amine.

Gasoline base stocks to which the glycol borate amine compounds of this invention are added may be any of those conventionally used in preparing a motor gasoline for a spark-ignited internal combustion engine, such as catalytic distillate, motor polymer, alkylate, catalytic reformate, isomerate, naphthas, etc. The gasoline will preferably contain a tetra-alkyl lead compound as an antiknock agent and a scavenging agent. The amount of the anti-knock agent will he usually at a level of approximately 3 ml./gal., but may range from /2 mL/gal. up to 6 mL/gal. The base gasoline may also include other common additives such as anti-oxidants, stabilizers, solvent oils, dyes, and the like.

The amount of compound to be added to motor fuels for purposes of the invention may vary, and is conveniently expressed in terms of percent by weight of boron. Ex-

cellent results have been obtained where the amount of compound is within the range of 0.001 to 0.01% boron by weight. Usually amounts greater than 0.005% by Weight cannot be economically justified.

The amine salts of this invention may be prepared in a variety of Ways, the simplest of which is to mix with stirring, stoichiometric quantities of a 1:1 (molar) glycol borate with an amine. The reaction is substantially spontaneous and is believed to proceed according to the following representation:

where R, R", and R' are defined the same as above.

The reaction may be carried out with or without a solvent. Where higher molecular Weight borates and/ or amines are employed, a solvent may be desirable to effect solution of the reactants. Preferred solvents are hydro carbons and especially aromatics which are normal gasoline components, and therefore need not be removed from the reaction product.

The reaction is mildly exothermic, but external heat, while not required, may be desirable to melt higher molecular Weight starting materials where, for some reason, the use of a solvent is to be avoided.

The glycol borate may be prepared by reacting one mol of boric acid with one mol of glycol. A detailed discussion of glycol borate preparations may be had by reference to United States Patent 2,741,548 to Darling et al. Any of the 1:1 (molar) glycol borates disclosed in this patent may be used.

Alternatively, the glycol borate amine compound-s may be prepared by simultaneously mixing boric acid or boric oxide, a glycol, and an amine together in the presence of of a solvent (such as toluene or xylene), removing the requisite amount of Water to form a 1:1 glycol borate, whereupon the amine will spontaneously react with the glycol borate to form the desired product.

EXAMPLE I BUTYLENE GLYCOL BORATE-DIAMYL AMINE A mixture of 18.0 g. butylene glycol, 12.4 g. boric acid, and mls. toluene were heated with stirring until 7.2 g. of water were removed by azeotropic distillation. The P oduct was allowed to cool to room temperature, whereupon 31.4 g. of diamyl amine were added with stirring. The spontaneous reaction product was a pale, yellow liquid.

EXAMPLE II HEXYLENE GLYCOL BORATE-DIBUTYL AMINE A mixture of 23.6 grams of hexylene glycol, 12.4 g. boric acid, and 100 mls. of toluene were heated with stirring until 7.2 g. of water were removed by azeotropic distillation. The product was allowed to cool to room temperature, whereupon 25.8 g. of dibutyl amine were added with stirring. The spontaneous reaction product was a clear, white liquid.

EXAMPLE III HEXYLENE GLYCOL BORATE-COCONUT 01L PRIMARY 7 AMINE (HGB-COA) 8.64 g. of hexylene glycol borate was admixed with 13.38 g. of Armeen C (a coconut oil primary amine derived from a mixture of fatty acids comparable to that found in coconut oil). The materials with stirring spontaneously reacted to form a dark brown liquid.

EXAMPLE IV HEXYLENE GLYCOL BORATE-OLEYL AMINE (HGB-OA) A mixture of 59.0 g. hexene glycol, 30.9 g. boric acid, 100 ml. xylene and 143.5 g. Armeen O (oleyl primary amine) was heated with stirring until the requisite 18.0

g. of water to produce a 1:1 (molar) glycol borate was removed by azeotropic distillation. The heating was stopped as the amine spontaneously reacted with the glycol borate to form an amber liquid reaction product.

Carburetor icing A. Test procedure: A 1955 Plymouth V-8 engine was equipped with a two-barrel carburetor. Air was supplied to the carburetor at a constant rate of 70 cu. ft. per minute by a specially designed air conditioner controlled at 45 F. and 85% relative humidity (conditions frequently found, and conducive to carburetor icing). All test con ditions for each of the runs were the same save for the amine salt additive.

The test consisted of running five cycles on each fuel. During each cycle the engine was operated at 2200 r.p.m. for 10 seconds and then de-accelerated normally to an idle of 600 rpm. for a maximum of 30 seconds. Performance of the engine was observed during each idle period, and a numerical merit rating based on the degree of rough idling and engine stalling was assigned to each cycle. Merit ratings were chosen from a scale ranging from 100 to an engine operating at a smooth idle over the idle period of a cycle would be entitled to a rating of 100, while an engine which stalled in less than 8 seconds of idle would get an 0 rating. The base fuel used had the following composition and specifications:

*Hexylene glycol borate-oleyl amine.

It can be seen that the addition of a minor amount of glycol borate amine to the base fuel improved performance by 12 merit rating units.

Carburetor deposits A. Test procedure: A 1954 Oldsmobile engine was equipped with a cleaned, standard 4 barrel Rochester carburetor and an air filter with the filter element removed. The air filter inlet was fed a mixture of exhaust gases from a slave engine, and blow-by gases from the crankcase of the test engine. Prior to running the test cycles, the carburetor was stabilized with the test fuel by running the engine unloaded at 1500 r.-p.m. for 15 minutes, throttling back and running the engine unloaded at 850 rpm. for miutes.

The test for each fuel ran about 2 hours during which time 4 cycles were run. Each cycle consisted of 30 minutes at idle followed by 5 full throttle accelerations to 3000 r.p.-m. All test conditions for each of the runs were the same, save for the glycol borate amine additive. At the end of each test the carburetor was removed and disassembled. The primary throats were inspected and rated on an 0- -l0 scale; the higher the number, the cleaner the carburetor. After being rated the carburetor was cleaned,

6 assembled, and remounted on an engine in preparation for the next test. The base fuel used consisted of 75% catalytic distillate and 25% straight run naphtha.

1 Hexylene glycol borate-dibutyl amino.

2 Hexylene glycol borate-diamyl amine.

3 Hexylene glycol borate-coconut oil amine. 4 Hexylene glycol borate-oleyl amine.

It will be noted that the lower molecular weight additives, while not harmful, had little or no effect on the reduction of deposits; the coconut oil and oleyl amine compounds showed a substantial improvement.

In connection with the carburetor deposit test outlined above, it was found that the addition of from 20 to weight percent hexylene glycol borate to a higher molecular weight amine compound (about C and above) produced unexpected results. As shown in the table below, hexylene glycol alone had no elfect on the amount of material deposited in the carburetor. When used alone in an amount equivalent to 0.002 and 0.001 weight percent boron, hexylene glycol borate oleyl-amine effected an improvement over the base fuel of 4.5 and 2.3 units, respectively. The 2.3 unit improvement was increased to 3. 8 units by the addition of an amount of hexylene glycol borate, equivalent to 0.001 weight percent boron. This improvement was entirely unexpected since the hexylene glycol borate, by itself, was ineffectual against carburetor deposits. The carburetors were rated on an 0-10 scale; the higher the number, the cleaner the carburetor.

TABLE VI Boron (wt. percent) Rating Base=4.5 Fuel in Fuel (Improvement over Base) 1 Hexylene glycol borate. 9 Hexylene glycol borate-olcyl amine.

Smoothness A. Test procedure: A 1956 Oldsmobile research engine with an 11:1 compression ratio was equipped with a vibration pick-up mounted on the engine block near the front main bearing, and pressure responsive pick-ups mounted in each of the combustion chambers. Crankshaft vibration and excessively high combustion chamber pressures are caused by surface ignition and manifest themselves in a rough running engine. By actual vibration and pressure count, it was possible to measure the efiect of an additive in suppressing surface ignition, thereby providing a smoother running engine.

The signal generated from each of the pick-ups was amplified and fed to an electronic counter. By adjusting the gain on the amplifier, it was possible to count cycles of varying levels of roughness. For purposes of this test, the counters recorded only those manifestations which were sufliciently severe to be apparent to the operator.

Each test fuel was run in the engine at 1700 r.p.m. and 15" Hg manifold vacuum for 25 minutes. The engine was then adjusted at 1800 rpm. and 8 Hg manifold vacuum. The counters were turned on and for 70 seconds counted firing cycles of abnormal roughness.

At the end of this period, the engine was throttled back and the carburetor was drained and flushed with the next pletely covered by rust after 100 hours.

test fuel. The base fuel used had the following composition and specifications:

Engler distillation Composition Percent vol.

Percent F.

saturates" 57 L131. 102 O1cfins 8 10 140 Aromaticsu 35 30 200 50 238 TEL (cc/gal.) 2.2 70 2276 API Gravity (60/60) 55. 64 90 850 El. 402

TABLE VII Vibrations counts e) Boron (wt. Pressure percent) in counts fuel (avg) Fuel none

Base 0 Base-l-H GBDBA* 0. 002 l73 -24 *Hexylene glycol borate-dibutyl amine.

Anti-rust A. Test procedure: 12-inch lengths of l-inch angle-iron were sanded on a belt sander. The specimens were placed in glass containers along with 400 mls. of test fuel, and the fuel in the containers was vigorously sloshed. After the addition of 4 mls. of water, the containers were sealed and mounted along radii of a large rotatable wheel. At a speed of 3 r.p.m., the wheel and specimens were rotated for 100 hours. At completion of the run, the metal specimens were observed and rated according 'to"ai1'arbitra'ry 0-l0 scale. A rating of 0 would be given to a specimen that showed no rust after 100 hours. A rating of would be given to a specimen that is com- The base fuel used had the following composition and specifications.

.. k 8 7 1 B. Test results:

TABLE VIII Boron Fuel (wt. percent) Rating infuel None 5. 6 0. 001 1. 0-2. 5 BflS0+HGB-COA 3 0. 001 1.

1 Hexyleue glycol boratedibutyl amine. Hexyleue glycol borate coconut-oil amine.

Bactericidal properties A Test procedure: The initial procedure was the same used for the anti-rust determination. At the end of hours of rotation on the wheel, 1 ml. of fuel was removed from each container for bacteriological examination, and mixed with 20 mls. of sterile agar nutrient (at 45 C.) in Petri dishes. The mixture on the dishes was then allowed to cool to room temperature, whereupon the agar congealed. Each dish was then inverted and placed in an incubator maintained at 37 C. After incubation for 48 hours, the colonies were counted using 1 Hexylene glycol borate-dibutyl amine. 2 Hexylene glycol borate-coconut oil amine.

3 Hexylene glycol borate-oleyl amine.

It is to be understood that various modifications of the present invention will occur to those skilled in the art upon reading the foregoing disclosure. It is intended that all such modifications be covered which'reasonably fall within the scope of the appended claim.

We claim: I

As a composition of matter, the product of the reaction of a 1:1 (molar) glycol borate containing 3 to 6 carbon atoms with a stoichiometric amount of an aliphatic amine selected from the group consisting of primary, secondary and tertiary alkyl amines wherein the alkyl contains from 3 to 18 carbon atoms, said product containing a minimum of 14 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 2,497,521 2/50 Trautman 260462 2,883,412 4/59 Lowe 260462 3,133,800 5/64 De Gray et al. 260-426 CHARLES B. PARKER, Primary Examiner.