US2644795A - Hydrocarbon oil composition - Google Patents

Description

Patented July 7, 1953 2,644,795 1 HYDROCARBON OIL COMPOSITION- Joseph .E. Fields, Dayton, Ohio, assignor to Mon- 'santo Chemical-Company, St. I ouis', Mo., acorporation of Delaware No Drawing. Application November-15,1950,

Serial No. 195,897-- I This invention relates to antifoaming hydrocarbon oils and deals more particularly with hy drocarbon oils containing, as anti-foaming agents, small amounts of certain ketonic esters;

The problem of foam inhibition is one of major 5 Claims. (01. 252-56) importance to all industries employing hydrocarbon oils under foam-inducing conditions. While most oils will foam to some extent due to vigorous agitation and aeration in a running engine, foaming becomes a problem only when loss of oil occurs by foam seepage or when so manyair bubbles are present in the oil that proper lubrication of bearing surfaces is impeded. Foaming isv often experienced with dry sump engines in which there is employed a scavenger pump for collecting oil from various engine parts and returning it to the lubricant reservoir. Here air maybe colv lected along with the oil and deposited in the reservoir. The design and operationof aircraft engines is such that foaming occurs more readily in this type of engine than it does in automotive engines.

properties have been met by the formulationand use of numerous chemicals which give these desirable properties to oils when admixed therewith, the use ofsuch additives makes the treated oils particularly susceptible to foaming. While light grade oils, e. g., SAE 10 grade oils, are almost 1 1 non foaming under the 'most severe" conditions,

when there are employed with these oils oneor more additives such as viscosity index improvers, extreme pressure resisting improvers, pour-point depressors, etc. The resulting improved oils do not retain their non-foaming characteristics and are frequently even more susceptible to foaming than are the heavygrade oils.

Hence, with the development of new high-speed engines and the provision of the new additive-type lubricants, the problem of foaming has assumed major importance. Attempts to solve the problem Foam and froth in hydrocarbon oils, however,

is not due solely to engine design. Although lo-' cation and design of the oil pump, oil sump and oil lines as well as modification of otherme chanical features may retard foam development, when certain oils are employed with high speed engines, mechanical control, alone, does not suffice. Herethe nature of crankcase oil is often the prime factor in foaming difiiculties. The heavier the grade of the oil or the higher the vis cosity of the oil, the more diiiicult it is to avoid foaming. Heavy grade oils-such as those employed in high-speed diesel and spark ignition engines operating under severe 'conditions'areparticularly susceptible to foaming. The heavy oils holdbubbles very firmly so that when foam is formed, it is very persistent. I

New developments in engine construction have constantly demanded lubricants having properties not possessed by crude hydrocarbon oils. Such properties are now generally imparted tolubricants by the use of additives. For example,"in order to satisfy the lubrication requirementsof hypoid gears, materials which impart extremepressure resisting properties are now generally added to gear lubricants. In most cases, however, the improvement attained in an oil by the use of additives is made only at the expense of increasing its susceptibility to foam. Thus, while the demands of modern engine design for ex-' treme pressure resisting lubricants, for anticorrosive lubricants, for lubricantsof increased viscosity and low pour-point and good 'detersive by defoaming existing oils, e. g., by submitting oils toheat-treatment, adsorption processes, filtering steps, etc, have proved of but little value. The most practical solution to this problem has been made by the use of anti-foam additives.

A number of anti-foam additives, i. e., antifoaming agents, foam depressingagents, foam depressants, anti-frothe'rs'or' foam suppressors,

ar known; but in prior art their use has been attended with numerous difliculties. Among disadvantages of such known additives are chemical reactivity with the lubricant or other oil additives, corrosive effect, susceptibility to decomposition upon heating, instability when exposed for long periods of time to ordinary atmospheric conditions, high cost, etc.

Now I havefound that foaming of hydrocarbon oils is efficiently retarded and even completely inhibited when there is added to such oils a small quantity, say, up to 1.0 'per cent by weight of a liquidaddition product of one mole of a saturated al'dehyde of from 1 to 18 carbon atoms 7 I with more than'one mole of a trialkyl aconitate in which the alkyl radical has from 1 to s carbon atoms. Addition products of this kind are described in the copending application of Tracy M.

Patrick and Earl W. Gluesenkamp, Serial No.

195,915 filed November 15, 1950. They are readily obtained by a free-radical-catalyzed addition reaction spbstantially according to the scheme in which R is an alkyl radical of from 1 to 17 carbon atoms, Y is an alkyl radical of from 1 to 8 carbon atoms, and n is an integer greater than one. Saturated aldehydes which may be employed in preparing the anti-foaming adducts are, for example, acetaldehyde, propionaldehyde, nbutyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, methylethylacetaldehyde, n-caproic aldehyde, isohexaldehyde, 2-ethylhexaldehyde, capric aldehyde, undecaldehyde, lauric aldehyde, palmitic aldehyde, stearic aldehyde, etc.

Aconitates which may be reacted with the above aldehydes to yield addition products having antifoaming properties are, for example, trimethyl, triethyl, triisopropyl, diethyl n-butyl, tri-sec.- butyl, tri-tert.-butyl, tri-n-amyl, methyl di-sec.-

amyl, tri-tert.-amyl, tri-n-hexyl, triisohexyl, 1311111- n-octyl, triisooctyl and tris(2-ethylhexyl) aconitate. A mixture of different alkyl aconitates may be employed, e. g., a mixture of triethyl aconitate and trihex'yl aconitate to give adducts having recurring triethyl ester andtrihexyl ester units.

Preparation of the present liquid mixture of adducts may be effected by simply contacting the saturated aldehyde with the aconitate inthe presence of a free-radical-1iberating agent such as a peroxidic compound at ordinary or increased. temperature until formation of the adducts has occurred, andremoving from the resulting reaction mixture any unreacted starting materials and 1:1 addition products.

The present aldehyde-aconitate adducts are effectiveanti-foaming agents when they are employed in very low proportions, i. e., in amounts of up to 1.0 per cent by weight, based on the weight of the total hydrocarbon oil composition. From .008 per cent to .05 per cent, of the adducts is preferred, depending upon the nature of the oil. Heavy oilsand oils containing foam-inducing adjuvants require more of the present antifoaming adducts than do base oils of good viscosity characteristics.

The anti-foaming effect of the aldehyde-aconitate adducts is not materially affected by the presence of other adjuvants in the oil. The present adducts are stable keto-esters which can be hydrolyzed only with difficulty, and since they are present in the oils in only very small quantities, the use of even very acidic or very basic additionsin the oil has substantially no effect-on the adducts. Hyrocarbon oils containing the present antifoaming agents are stable when stored over long periods of time and also when subjected to heat and pressure conditions of engine and motor operation,

While the antifoaming effect of the aldehyde aconitate adducts is obtained when they are employed in concentrations of up to 1.0% by weight, the adducts may be incorporated into hydrocarbon oils in much higher proportions, e. g., in amounts of up to 10 per cent or even 50 per cent of the weight of the hydrocarbon oil to give concentrates. Oils containing such high proportions of the adducts may be manufactured and sold for use as lubricant additives. Addition of small amounts of such concentrate to hydrocarbon oils may be made so as to supply an oil containing suitable quantities of the adducts.

Hydrocarbon oils which are rendered substantially antifoaming by incorporation therein of quantities of up to 1.0 per cent of the present adducts are synthetic or petroleum stocks of varying viscosities such as lubricating oils for internal combustion engines and motors, diesel fuels and lubricants and pressure transfer media, e. g., in-

dustrial lubricants, process oils, hydraulic oils, turbine oils, cutting oils, fluid greases, gear oils, shock absorber oils, spindle oils, journal bearing oils, pneumatic tool lubricants, etc. They may be synthetic or natural hydrocarbons of any type, i. e., parafiinic, naphthenic or blended.

The invention is further illustrated, but not limited, by the following example Example The anti-foaming properties of lubricants may be determined according to the procedure generally described, in Designation Ll2-445 of the Coordinating Lubricants Research Committee of the, Coordinating Research Council. New York. Briefly this procedure involves bubbling air or an inert gas such as nitrogen through the hydrocarbon oil to be tested, employing standard apparatus and standard conditions.

The oil was placed in a standard -ml. graduated cylinder in the top of which was inserted a two-hole. rubber stopper. An air-inlet tube extended through this stopper, to the bottom of which was attached a gas diffuser or porous stone sphere. The length, of the inlet tube was adjusted so thatwhen the apparatus was assembled, the sphere just touched the bottom of the cylinder. The sphere was attached to the inlet tube by means oflitharge and glycerine, or by a copper tube soldered to the diffuser-stone coupling. The oil bath used was capable of controlling temperature at 200:+;1 F. A93.3i0.6 C.), large enough topermit the cylinder to be immersed at least to the 90-ml. mark, and arranged to permit the visual observation of the graduations on the cylinder.

Dry nitrogen air was supplied at the rate of 0.2 cubic, foot per hour, employing a calibrated flowmeter. The. sample was heated to F. (48.9 C.) and then cooled, before testing, to 75i5 F. (23.9i2.8 C.) in aconstant temperature room. 25 cc. of oil was used for each test.

With the air hose disconnected between the fiowmeter and the. delivery tube to the diffuser stone, the stone was allowed to soak in the oil for 5 minutes, at the end of which time the air flow (0.2 .cu. ft. per hour) was started through the stone. Zero time was noted when the air or nitrogen bubbles started to rise from the stone. Readings of thetop and bottom foam levels were taken at the end of a 5-minute period. The volume of foam was calculated from the two readings.

Employing the testing procedure described above there was determined. the anti-foaming effeet of a liquid mixture of 2-ethylhexaldehydetributyl aconitate adducts when added to a Champlin 30 SAE base oil in concentrations of from 0.02% to 0.05% by weight of the oil. The liquid mixture of adducts. B. P. above 172 C./0.5 mm. n l.4556, was prepared by the addition reaction of 2eethylhexaldehyde with tributyl accnitate in the presence of benzoyl peroxide, as described in the previously cited copending application. The following results were obtained:

Concentration of adduct, weight Foam, cc. 0.02 10 0.03 none 0.05 none In the absence of an additive, the Champlin 30 SAE oil gave 71 cc. of foam under the same testing conditions.

Non-foaming hydrocarbon oil compositions may be obtained by incorporating into such oils,

in a quantity of up to 1.0 per cent based on the Weight of the composition, other liquid mixtures of adducts of one mole of a saturated aliphatic aldehyde with from 2 to 20 moles of trialkyl aconitates. Thus instead of the 2-ethy1hexaldehyde-tributyl aconitate adducts employed in the above example there may be used, e. g., adducts of 1 mole of n-butylaldehyde, of acetaldehyde or of hexaldehyde with from 2 to 20 moles of a trialkyl aconitate such as tri-n-amyl, triisopropyl or tri-whexyl aconitate. The present adducts impart anti-foaming properties to hydrocarbon oils, generally,'in the presence or absence of other customarily employed additives such as extreme-pressure resisting additives, detergent additives, etc,

What I claim is:

1. A substantially foam-resisting hydrocarbon oil composition containing up to 1.0 per cent by weight, based on the weight of the composition, of a liquid mixture of adducts having the formula in which R, is an alkyl radical of from l-to 1'7 carbon atoms, Y is an alkyl radical of from 1 to 8 carbon atoms and n is an integer of from 2 to 20.

2. A lubricant composition containing a hydrocarbon oil, and up to 1.0 per cent by weight, based on the weight of the composition, of a liquid mixture of adducts having the formula in which R is an alkyl radical of from 1 to 17 carbon atoms, Y is an alkyl radical of from 1 to 8 carbon atoms and n is an integer of from 2 to 20.

3. A lubricant composition containing a hydrocarbon oil and up to 1.0 per cent by weight,

based on the weight of the composition of a liquid mixture of adducts having the formula in which Bu denotes the butyl'radical, R is an alkyl radical of from 1 to 1'7 carbon atoms, and n is an integer of from 2 to 20. I

5. A lubricant composition containing a hydrocarbonoil and up to 1.0 per cent by weight, based on the weight of the composition, of a liquid mixture of adducts having the formula 1 CHaCHgCH2CHCH2CO[-([DH (1) $112 111 CHQCHQ COOBu COOBu oooBu in which Bu denotes the butyl radical and n is an integer of from 2 to 20.

JOSEPH E. FIELDS.

References Cited in the file Of this patent UNITED STATES PATENTS Name Date Gleason July 10, 1945 Borsofi; Oct. 31, 1950 Borsoff Oct. 31, 1950 Grammaria Oct. 9, 1951 Bartlett Nov. 20, 1951 OTHER REFERENCES Number Foaming of Aircraft-Engine Oils as a Problem in Colloid Chem. NACA report ARR. No. 4 I 05- 1944-McBain et a1.

Claims (1)

1. A SUBSTANTIALLY FOAM-RESISTING HYDROCARBON OIL COMPOSITION CONTAINING UP TO 1.0 PER CENT BY WEIGHT, BASED ON THE WEIGHT OF THE COMPOSITION, OF A LIQUID MIXTURE OF ADDUCTS HAVING THE FORMULA