US2653911A - Hydrocarbon oil compositions containing telomeric polyalkyl oxoesters as anti-foaming agents - Google Patents

Description

Patented Sept. 29, 1953 HYDROCARBON on, COMPOSITIONS CON- TAINING .TELOMERIC ,POLYALKYL X0 ESTERS AS ANTI-FOAMING AGENTS Joseph Fields and Tracy Patrick; .1 Dayton, Ohio, assignors to Monsanto" Chemical Company; StaLi'niis, Mo., a: corporation of Dela ware 1% Drawing. paiafios m m 1, 1952',

SerialNo. 269,602 1'2 Glaiiiiis. (Cl; 252-56)" This invention relates toantifoaming hydrocarbon oils and deals more particularly with hydrocarbon oils containing small" amounts of liouidtelomeric polyalkyl oXoestersl The problem of foam inhibition is one"of ma= jor importance to all industries employing Hydrocarbon oils under foam-inducing conditions;- While most oils wil1 foam to some extent" due to vigorous agitation and aeration in arunningengine, foaming becomes a problemonly when loss of oil occurs by foam seepage or" when'so many air bubbles are present in the oil that proper lubrication of bearing surfacesisimpeded. Foaming is often experiencedwith drysurnp" engines in which there is employed a'scave'nger pump for collecting oil from various engine parts" and returning it to the lubricant reservoir. Here air may be collected alongwiththe oil and deposited in the reservoir. The design and opera tion of aircraft engines issucli" that foaming 0c curs more readily in this type-of engine thanit does in automotive engines.

Foam and froth in hydrocarbon oils, however;- is not due solely to engine-design. Although-loca tion and design of the oil pump, oil suinp and oil lines as well'as modification of other engineering features: may retard foam'develop ment, "when certain oils are employed with high; speed engines, mechanical" control, alone, does not suffice. Here, the nature of the crank 'case oil is often the prime factor in roaming diifi culties. Theheavier the gradeof the oil' o'r' th'e higher the viscosity of the oil, the more dif ficult it is to avoidfoaming. Heavy gradeoils; such as those employed in' high-speed di'es'el and spark ignition engines operating under severe conditions are particularly susceptible to foa'rn ing. The heav oils hold bubbles very firmly-so that when foam is formed, it is very persistent;

New developments in engine constructionhave" constantly demanded lubricants'havihg proper-'- ties not possessed by crude hydrocarbon oils.- Such properties are'nowgener'ally conferredto lubricants by the use of additives; For eii'arh ple, in order to satisfy the lubrication require: ments of hypoidgears, materials, whichim expense of increasing its susceptibility to foam;

Thus, while-the demandsof modern engine'*de-- sign for extreme pressure resisting lubricants;

for anticorrosive lubricants, for lubricantsof'iIf: creased viscosity and 'low" pour-point andgfoo'df detersive properties have" been met by theior' 2. inulation' and use of numerous chemicals which give these desirable properties to oils when adniixedtherewith, the use of such additives makes the treated oils particularly susceptible to foaming. While light grade oils, e. g., SAE 10 grade oils are almost non-foaming under the most severe conditions, when there are employed with these oils one or more additives such as viscosity index improver's, extreme pressure resisting improver's','pour'-point depressors, etc, the result improved oil's do notretain their nonreamin chalracteristics and are frequently even nioresusceptibleto foaming than are the heavy del 4 I-I ence, with thedevelopmer'it-of new high-speed engines and the provision" of the new additivetyp'e-lubricants', the problem of foaming has assumed major importance; Attempts to solve the problem by defoaming ensuing o'il's, e. g., by submitting oils to" heat treatment, absorption processesyfilteringlstep's, etch,- have proved of but little value, The most practical solution to this problem has-been made by the use of antifoam additives. j V

.A number of'antifoani additives, i. e., antifoaming' agents} roam depressing agents, foam depressants; antifrotlierspr foam sup'pressorsarc known; but in prior art their use has been attended' with numerous difficulties. Among disadvantages'ofsuch known additives are chemical reactvity with' the'lubricant or other oil addieves;massive-eases susceptibility to decomposi tion upon-' 'h'eating instability when exposed for long-period'sof time to ordinary'atmospheric conditions, high co'stfetc.

Now we hav'e round' that foaming of hydrocarbon oils is: efficiently'retarded and even completelyinhibited' when-there is added to such oils' a sr'nall quantity, say; from 0.001 per cent to 1.0 percent by" v'vig'ht of a liquid mixture of t'eldrn'ersprepar'ed byreactionof onevmole of a saturated, alirilria'tic aldehyde of from 2 to 13 carbon atomsfwith n'iore than' one mole of certain esters of m-unsaturated aliphatic, dicarbokylicacids. Teloiners of this kind are described inthe copending application of Tracy M; Fatrick, Jr .'and Earl W. Gluesenkamp, Serial'No. 200,101, fi e peeember' 9; 1950; They are readil obtained by a free radicalcat'alyzed addition re in which R. is an alkyl radical of from 1 to 12 carbon atoms, X is selected from the class consisting of hydrogen and the methyl radical and R and R" are selected from the class consisting of alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n is an integer greater than one.

Saturated aldehydes which may be employed for the preparation of the present adducts are, ifor example, acetaldehyde, propionaldehyde, nbutyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, methylethylacetaldehyde, trimethylacetaldehyde, n-caproic aldehyde, isohexaldehyde, Z-ethylhexaldehyde, octaldehyde, capric aldehyde, undecaldehyde, lauric aldehyde, palmitic aldehyde, stearic aldehyde, etc. Esters which react with the above aldehydes to yield telomers which are useful for the present purpose are, for example, dimeth'yl, diethyl, diisopropyl, di-n-butyl, bis(2-ethylhexyl), dicyclohexyl, dibenzyl, di-p-tolyl, dihexadecyl, and didodecyl maleate; dimethyl, diisobutyl, dioctadecyl, diphenyl and dicyclopentyl fumarate, dipropyl, dioctlyl, bis(2-phenylethyl) and di-a-naphthyl citraconate, dimethyl, diundecyl, dixenyl and dibenzyl mesaconate, etc.

The liquid telomeric polyalkyl oxoesters are effective antifoaming 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 .01 per cent to .10 per cent of the telomeric esters is preferred, depending upon the nature of the oil. Heavy oils and oils containing foaminducing adjuvants require more of the present antifoaming adducts than do base oils of good viscosity characteristics.

Particularly valuable as antifoaming additives for hydrocarbon oils are liquid telomeric polyalkyl oxoesters in which one mole of a saturated, unsubstituted aliphatic aldehyde of from 2 to 12 carbon atoms has combined with from 2 to 30 moles of an ester selected from the class consisting of dialkyl and dicycloalkyl maleates, fumarates, mesaconates and citraconates in which each alkyl radical and each cycloalkyl radical has from 1 to 12 carbon atoms. The dialkyl and di cycloalkyl maleates in which each alkyl radical has from 1 to 8 carbon atoms are commercially available, inexpensive starting materials, and telomers prepared from such maleates are the preferred antifoaming agents at present.

The antifoaming effect of the aldehyde-ester telomers is not materially afiected by the presence of other adjuvants in the oil. The liquid telomers are stable polyesters 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 additions in the oil has substantially no effect on the telomers. Hydrocarbon 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 liquid telomers is obtained when they are employed in concentrations of up to 1.0 per cent by weight, they 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 telomers may be manufactured and sold for use as lubricant additives. Addition of small amounts of such concentrates to hydrocarbon oils may be made so as to supply an oil containing suitable quantities of the telomers.

Hydrocarbon oils which are rendered substantially antifoaming by incorporation therein of quantities of up to 1.0 per cent of the present telomeric oxoesters 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., industrial 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 antifoaming properties of lubricants may be determined according to the procedure generally described in Designation L-l2-445 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.

Theoil was placed in a standard IOU-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 that when the apparatus was as 'sembled, the sphere just touched the bottom of the cylinder. The sphere was attached to the inlet tube by means of litharge or glycerine, or by a copper tube soldered to the difiuser-stone coupling. The oil bath used was capable of controlling temperature at 200i1 F. (93.3:0.6

' 0.), large enough to permit the cylinder to be immersed at least to the ml. mark, and arranged to permit the visual observation of the graduations 0n the cylinder.

Dr nitrogen or air was supplied at the rate of 0.2 cubic foot per hour, employing a calibrated flowrneter. The sample was heated to F. (48.9" 0.), and then cooled, before testing, to 75i5 F. (23.9i2.8 C.) in a constant 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 the top 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 were determined the antifoaming effects of various aldehydemaleate telomers when added to a Champlin 30 SAE base'oil in concentrations of from 0.05% to 005% by weight of the oil. The telomers were prepared by heating mixtures of the aldehyde and maleate indicated below in the presence of benzoyl peroxide as catalyst, and removing from the resulting reaction mixture any unreacted material and 1:1 addition product by distilling the mixture up to B the head temperatures shown below, as described in the previously cited copending application.

Reactants Used e B. P. of Telomer, l??? above Head Temp.

Aldehyde Maleate Of 1 Butyraldehyda. Dicyclohexyl. 185 O./l mm. 2 .do bi]sJ-2-(lil)th-yl- 184 C ./0.5 mm.

exy 3 Heptaldehyde .do 2102 GJOXZ 4 2 Ethylhexal- Diethyl 136 C./0.8 mm.

dehyde.

The following antifoaming values were obtained with these telomers:

Foam (cc.) in 5 Min. Additive in p. p. m; of-oil Additive, rrelome'r N0.

None. 500 200 so Nonfoaming hydrocarbon oil compositions are also obtained by incorporating into such oils in a quantity of up to 1.0 per cent, based on the weight of the composition, telomers of other saturated aliphatic aldehydes of from 2 to 13 carbon atoms and other dicarboxylates having the general formula o o o R do on" in which X is selected from the class consisting of hydrogen and the methyl radical and R and R" are selected from the class consisting of alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms. Thus instead of the telomers tested above, there may be advantageously employed, e. g., telomers of acetaldehyde and didodecyl fumarate, propionaldehyde and dil-tolyl citraconate, n-valeraldehyde and dinaphthyl mesaconate, lauric aldehyde and dimethyl fumarate, etc. The present telomers impart antifoaming properties to hydrocarbon oils, generally, in the presence or absence of other customarily employed additives such as extremepressure resisting additives, detergent additives, etc.

This is a continuation-in-part of our application Serial No. 217,324, filed March 23, 1951, now abandoned.

What we claim is:

1. A hydrocarbon oil composition containing up to 1.0 per cent by weight, based on the total composition, of a liquid telomeric polyalkyl oxoester having the general formula R.CO CH 011- ]H JJOOR' 4700B" n in which R is an alkyl radical of from 1 to 12 carbon atoms, and R and R" are selected from the class consisting of alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n is an integer greater than one.

2. A hydrocarbon lubricant composition containing up to 1.0 per cent by weight, based on the total composition, of a liquid telomeric polyalkyl oxoester having the general formula 11.00 -on-cn- 1H 00R coon" in which R. is an alkyl radical of from 1 to 12 .6 carbon atoms, and R. .andR""areselecte;d from the class consisting of alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n is an integer greater than one.

3. A substantially antifoaming hydrocarbon lubricant composition containing up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula CHa(CH2)a-CQ on OH ]H oooo ioooy in which Cy denotes the cyclohexyl radicalfland n is an integer greater than one.

4. A substantially antifoaming hydrocarbon lubricant composition containing up to 1.0 per cent by Weight, based on the total compositiomo'f a liquid telomer having the formula CH- 11;. OOAlk c-ooalk in which Alk denotes the .2-ethylhexyl radical and n is an integergreater than one.

5. A substantially .antifoaming hydrocarbon lubricant composition containing up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula in which Alk denotes the 2-ethylhexyl radical and n is greater than one.

6. A substantially antifoaming hydrocarbon lubricant composition containing up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula in which Et denotes the ethyl radical and n is an integer greater than one.

7. The method of imparting antifoaming propperties to hydrocarbon oil compositions which comprises incorporating into said compositions up to 1.0 per cent by weight, based on the total composition, of a liquid telomeric polyalkyl oxoester having the general formula in which R is an alkyl radical of from 1 to 12 carbon atoms, and R. and R." are selected from the class consisting of alkyl, cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n is an integer greater than one.

9. The method of imparting antifoaming properties to hydrocarbon lubricant compositions which comprises incorporating into said compositions up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula CHs(CHz)a.CO CH CH- 1H JOOCy JJOOCY n in which by denotes the cycloalkyl radical and n is an integer greater than one.

10. The method of imparting antifoaining properties to hydrocarbon lubricant compositions which comprises incorporating into said compositions up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula ormcnmco OH CH H I: OOAlk dooAlkl .in which Alk denotes the 2-ethylhexy1 radical and n is an integer greater than one.

11. The method of imparting antifoaming properties to hydrocarbon lubricant compositions which comprises incorporating into said compositions up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula in which All; denotes the 2-ethylhexyl radical and n is an integer greater than one.

. 12. The method of imparting antifoami'ng properties to hydrocarbon lubricant compositions which comprises incorporating into said compositions up to 1.0 per cent by weight, based on the total composition, of a liquid telomer having the formula OHz(CHi)a?H.OHz.OO[OH-GH :lH

in whichEt denotes the ethyl radical and n is an integer greater than one.

JOSEPH E. FIELDS. TRACY M. PATRICK, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,417,833 Lincoln et a1. Mar. 25, 1947 2,430,858 Borsoff et a1 Nov. 18, 1947 2,528,466 Borsofi' et a1 Oct. 31, 1950

Claims (1)

1. A HYDROCARBON OIL COMPOSITON CONTAINING UP TO 1.0 PER CENT BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF A LIQUID TELOMERIC POLYALKYL OXOESTER HAVING THE GENERAL FORMULA