US2799650A - Foam inhibition of oil - Google Patents

Description

atent FOAM INHIBITION OF OIL John P. McDermott, Springfield, and Malcolm F. Hurley,

Elizabeth, N. J., assignor to Esso Research and Engineermg Company, a corporation of Delaware No Drawing. Application August 1, 1951, Serial No. 239,851

3 Claims. (Cl. 252-325) The present invention relates to the foam inhibition of oils and particularly to the prevention of foaming and frothing in organic compositions such as hydrocarbon oils and related materials which contain additives tending normally to promote foaming. The invention is applicable particularly to lubricating oils containing detergent additives and the like but it is applicable also to other liquid hydrocarbon oils having a viscosity ranging between that of kerosene up to very heavy viscosities which are characteristic of the most viscous lubricating oils.

As is well known in the prior art, lubricating oils, hydraulic oils and the like which foam excessively frequently cause operating difiiculties in machinery as well as in the processing of the oils themselves. Various materials have been proposed in the past for adding to such oils to inhibit their foaming. In recent years there has been a marked trend toward the use of detergent additives, particularly in lubricating oils and hydraulic oils, and, to a lessor extent, in fuel oils. These additive materials, which are desirable because they prevent sludging, deposition of gum and the like, are strong foam promoters and the modern tendency to use such materials in increasing quantities gives rise to increasing difiiculties with foaming.

It has been proposed in the past to inhibit foaming of organic compositions by adding minor proportions of various materials including fluorinated hydrocarbons, long chain alcohols, and small quantities of silicone polymers having foam suppressing characteristics in oils. The action of these anti-foamants appears to be quite specific and their activity cannot, in general, be predicted. Anti-foaming activity appears to have some relation to oil-insolubility as well as to surface tension but the factors which determine whether a given oil composition will foam are not clearly understood.

In general, the heavier the hydrocarbon oil and the greater its content of detergent additive, the greater will be its tendency to foam and the more difficult to inhibit its foaming. The foaming tendency, however, varies also with the particular type of oil and varies even more with the particular type of detergent, or other foam promoting additive. The fatty acid soaps of most metals, the oil soluble sulfonates, various aliphatic esters and amines and the salts of alkylated aromatic compounds such as alkyl phenol sulfides, alkyl phenolates, the phosphorus sulfide treated derivatives of such materials and the like, frequently tend to promote foaming in conventional mineral base hydrocarbon oils. The degree of foaming in each case varies with the particular constituents and the type and degree of agitation to which the oil is subjected.

In general, prior art attempts to prevent foaming of oils have been based upon the addition of certain antifoaming materials to the oil compositions. One feature of the present invention resides in the discovery that a pretreatment of the foam promoting additive itself, before addition to the oil, can greatly reduce the foaming tendency of oil containing the additive.

According to the present invention, foam promoting additive of the general type mentioned above, may be treated in a very simple and inexpensive manner to reduce greatly their tendencies to foam upon agitation of oil compositions containing them. The treatment consists in treating such additives with an aliphatic ketone containing from about 3 to about 7 carbon atoms. The treatment is rather specific and higher ketones are not useful. Thus acetone, methyl-ethyl ketone, methyl-propyl ketone, diethyl ketone, ethyl-propyl ketone, mesityl oxide ((CH3)2C=CHCOCH3), diisopropyl ketone methylbutyl ketone, and ethyl butyl ketone are all useful. The unsaturated ketone, mesityl oxide, is particularly effective with such materials as the alkaline earth metal salts of alkyl phenol sulfides and their phosphorus sulfide treated derivatives but the other ketones mentioned are quite effective also. The ketones of the normal as Well as the isoalkyl type may be used.

The quantity of ketone used should be between 0.1% and 25% of the weight of the additive or detergent material per se. Proportions in the range of about 3 to 20% are preferred, especially around 10%.

.A number of experiments were conducted to show the effect of treating detergent additives of various types which detergents were added to mineral lubricating oils of SAE 30 grade in concentrations of 5% for the foaming test.

In general the additive and the ketone treating agent were stirred together and heated at a moderately elevated temperature within the range of about to 170 C., with continued rapid stirring, accompanied by blowing with nitrogen. The treating temperature depends of course both upon the material treated and the treating agent used. With acetone the treating temperature in the neighborhood of 80 C. appears to be desirable for phenol sulfide type detergents. For methylethyl ketone, the treating temperature for such detergents should be about C., and about 120 C., for methyl propyl ketone. For mesityl oxide the treating temperatures used in the examples below were around 160 C., and for di-isopropyl ketone about 170 C. The results of these treatments, as indicated in standard foaming tests (ASTM Foam Test D892-64T) are indicated in the following table. In this Table, the detergent A was a barium salt of di-isobutyl phenol sulfide. Detergent B was a similar salt, treated however with P285 to improve its performance in certain types of mineral lubricating oil, combined with oil soluble calcium petroleum sulfonate. Detergent C was an alkaline barium alkyl phenol sulfide in combination with oil soluble calcium petroleum sulfonate.

Table I.Efiect of ketone treatment of additives on foaming BLENDS IN SAE 30 OIL ASTM Foam Test D892-46T Wt. Deter- Per- Ketone Treat- 75 F. 200 F. 75 F. (After gent cent ment 200 F.)

Fl. FS FT li FI FS A 5 None l. 600 500 650 0 595 485 A 5 Mesityl Oxide, 370 290 230 0 345 270 10 B 5 Non? 430 425 0 495 430 B 5 Methyl Ethyl 230 0 25 0 0 fietone, B s Acetone,10% 300 0 25 o o B 5 Diisopropyl 20 0 40 0 15 0 Ketone, 10%. O 5 None 470 410 230 0 465 400 C 5 Methyl Ethyl 0 30 0 180 0 Ketone, 10%. G 5 Acetone, 10%. 0 40 0 170 0 O 5 Methyl 10 0 30 0 10 0 Propyl Ketone, 10%. O 5 Mesityl 0x- 15 0 35 0 15 0 lde, 5%. O 5 Mesityl 0x- 20 0 30 0 20 0 ide, 1%.

Table I.--Continued BLENDS IN SAE 50 OIL 1 Foaming tendency. Z Foam stability.

It will be understood that the oil compositions which are subjected to the treatments described above form newand useful products, and that the treatments are applicable to fuel oils, hydraulic oils, diesel fuels, gear lubricants, crank case lubricants, and various greases and types of hydrocarbon oil compositions having a viscosity at least as great as that of kerosene. The oil compositions may incorporate various other conventional additives such as anti-oxidants, pour point depressants, corrosion inhibitors, detergents, film strengthening agents, anti-friction agents, extreme pressure agents, anti-rust agents, and the like as will be apparent to those skilled in the art. While reference has been made in general to the hydrocarbon, or mineral base oils, the invention is applicable also to other organic oils consisting of, or containing synthetic oils such as polyesters, polyglycols, polyglycol-ethers and the like so far as the same problems of foaming and foam inhibition are encountered therein.

What is claimed is:

1. The product of the treatment of an oil-soluble foampromoting detergent selected from the group consisting of the alkaline earth metal salts of alkyl phenol sulfides, the phospho-sulfurized derivatives of said salts and mixtures of said salts, with 0.125% of its weight of mesityl oxide at a moderately elevated temperature in the neighborhood of about 160 C. while stirring, said product having a reduced tendency to promote foaming.

2. The process of substantially reducing the tendency of detergent additives to promote the foaming of organic oil compositions containing the same, which comprises stirring and heating an additive selected from the group consisting of the alkaline earth metal salts of alkyl phenol sulfides, the phospho-sulfurizcd derivatives of said salts, and mixtures of said salts, prior to incorporation in said oils together with 01-25% by Weight, based on the additive, of mesityl oxide at a moderately elevated temperature in the neighborhood of about 160 C.

3. An oil composition of reduced foaming tendencies comprising a major proportion of an organic oil composition of viscosity at least as high as kerosene and a minor detergency-improving proportion of about 5% by weight of a normally foam-promoting detergent additive selected from the group consisting of the alkaline earth metal salts of alkyl phenol sulfides, the phospho-sulfurized derivatives of said salts, and mixtures of said salts, which has been stirred and heated prior to incorporation in said oil, together with about 01-25% by Weight, based on the additive, of mesityl oxide at a moderately elevated temperature in the neighborhood of about 160 C.

References Cited in the file of this patent UNITED STATES PATENTS 2,430,858 Borsoif et a1. Nov. 18, 1947

Claims (1)

1. 3. AN OIL COMPOSITION OF REDUCED FOAMING TENDENCIES COMPRISING A MAJOR PROPORTION OF AN ORGANIC OIL COMPOSITION OF VISCOSITY AT LEAST AS HIGH AS KEROSENE AND A MINOR DETERGENCY-IMPROVING PROPORTION OF ABOUT 5% BY WEIGHT OF A NORMALLY FOAM-PROMOTING DETERGENT ADDITIVE SELECTED FROM THE GROUP CONSISTING OF THE ALKALINE EARTH METAL SALTS OF ALKYL PHENOL SULFIDES, THE PHOSPHO-SULFURIZED DERIVATIVES OF SAID SALTS, AND MIXTURES OF SAID SALTS, WHICH HAS BEEN STIRRED AND HEATED PRIOR TO INCORPORATION IN SAID OIL, TOGETHER WITH ABOUT 0.1-25% BY WEIGHT, BASED ON THE ADDITIVE, OF MESITYL OXIDE AT A MODERATELY ELEVATED TEMPERATURE IN THE NEIGHBORHOOD OF ABOUT 160*C.