US2356340A

US2356340A - Metal soaps

Info

Publication number: US2356340A
Application number: US347482A
Authority: US
Inventors: Eger V Murphree
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1937-12-23
Filing date: 1940-07-25
Publication date: 1944-08-22
Anticipated expiration: 1961-08-22

Description

1 encies as well as increasing oiliness.

' to 4 hours.

Patented Au 22, 1944 umTEos'rA'rEs PATENT "OFFICE l I I I v margins I 'sstsra 'asaatgamma:

NoDrawing. Original application December 23, 1937,v Serial N0. 181,374. Divided and this applic'ation July 25, 1940, Serial No. 347,482

8 Claims. .(Cl. 260-448) This invention relates to lubricating oils for Diesel engines and is more particularly concerned with certain addition agents which when added to non-waxy lubricating oils greatly improve their properties.

It' is known that certain metallic soaps such as aluminum stearate and aluminum naphthenate improve the properties of lubricating oils for Diesel engines particularly with-respect to decreasing ring' sticking and varnish forming tend- A serious objection to the use of aluminum stearate for this'purpose is that it tends to-settle'out orgel upon standing; An objection to'the use of aluminum naphthenate is that it requires a temperature of 300 to 400 F. for solution in oil, and at these temperatures color deterioration is inevitable and unavoidable.

It is desirable touse a metallic soap which'has all of the desirable properties of these aluminum soapsbut which does notsettle out onfstanding and does notrequire temperatures for-solution high enough to cause color deterioration.

It has now been found that metallic soaps of acids obtained by the oxidation of sweater oil form extremely stablesolutions in non-waxy lubricating oils and can be completely dissolved in the oily layer. The aqueous layer contains the sodium soaps of the desired acids along with a small amount of unsaponiilable materials. The

unsaponiflable materials are then removed either I by naphtha extraction or by vaporization. Sulfuricacid is addedv to the sodium soaps to liberate the acids. The acids are then washed and the alkali (sodium, for example) soap is first preamounts of 0.1 to 3% in lubricating oil at temperatures between 175 and 200 F. at which no color deterioration occurs. The nature of these soaps and the method of preparing them will be fully understood fromthe following description:

In dewaxing an oil containing pressable wax, the wax precipitated in the process is called crude slack wax. 'This contains varying quantities of oil which is carrieddown with the wax.- The crude slack wax-is warmed to sweat out the oil.

The sweated wax is called crude scale wax, and

the oil obtained is called foots oil. The crude scale wax is subjected to. another sweating operation and the oil so obtained is called sweater oil. It is this sweater oil obtained from the sweating of crude scale wax which is used as the starting material for the preparation of the acids desired in the present process.

Sweater oil is distinguished from crude scale wax by the fact that it contains relatively much larger quantities of oil. 1

The sweater oil is oxidized with air or other gas containing free oxygen at a temperature between about 200 and 350 F. for a period of 2 Variouscatalytic materials such as potassium permanganate, manganese stearate or soda ash may be used to promote the oxidation.

The reaction product is then saponified with caustic soda preferably containing some methyl alcohol. Thereafter, the mixture is thoroughly agitated and the aqueous layer is separated from of the total acid and No. 6 cut pared. The alkali soap, solution is then addedv to.

an' aluminum-s'ul fate solution, a slight excess of the' latter being used. It will be understood that if other metallic soaps are desired, appropriate vsolutions of the metal salts will be used or the soaps may be prepared by direct cooking of the acids with appropriate metallic oxides or hydroxides. r

. The aluminum soap is washed free of inorganic salts and may then be dried or may be incorporated directly in the oil without drying, in which 'latter case the moisture is removed from 'the compounded oil by blowing with air or an inert gas.

The metallic soap is'added to the oil in amounts of 0.1 to 3%. The oil is heated to a temperature between about 175 and 200 F. and the soap stirred into it. a

Various other metalsbesides aluminum may be used, such as calcium, nickel, cobalt, magnesium, manganese, chromium, tin, zinc, etc. These soaps may be prepared as indicated above by adding the sodium soapto a solution of the metallic salt. -Other methods of preparation are, or

' 50 to 65% of the entire acid product.

The acid numbers and saponification numbers respectively are approximately as follows:

- f Saponifl Acid No. cation number Crude acid product 161 238 No. 6 out l- 239 It is found that the soaps prepared from sweater oil acids are markedly diflerent in properties from those prepared from oxidized scale wax. For example, the acid and saponification numbers compare as follows:

It is also found that the soaps of the No. 6 cut of oxidized scale wax as such are substantially insoluble in mineral oils whereas the soaps of the No. 6 cut of sweater oil acids are relatively much more soluble.

The following example illustrates the use of the improved soap:

1.7% of aluminum soap of the No. 6 cut of the distillate of acids prepared by the oxidation of "sweater oil is added to a non-waxy naphthenic oil obtained from a Coastal crude and having a Saybolt viscosity at 210 F. of 55 seconds and the mixture heated to about 175 to 200 F. until complete solution is effected. After standing in storage for 3 months, the oil shows no haze, gelling or other evidence of separation of the soap, but remains clear, bright and of excellent appearance.

This oil was tested for 250 hours operation in a Caterpillar Diesel engine and showed superior performance over blends of aluminum naphthenate or the aluminum soap of acids derived from the oxidation of crude scale wax in the same oil.

In some instances, e. g. in the case of the calcium, magnesium, zinc, manganese and similar soaps, difficulties may be encountered in dissolving them in certain mineral lubricating oils. In such cases, it has been found advantageous to add a solubilizing agent (about 5100% or more of the weight of the soap added) to prevent gel formation and to overcome other efiects of deficiency in solubility of the soaps. Such solubilizers may be free fatty acids, fatty esters, naphthenic acids or, esters, aromatic fatty acids such as phenyl stearic acid or their esters, organic esters of inorganic acids or aromatic polybasic acids, high molecular weight alcohols, alcohol-esters, alcohol-ethers, ether-esters, and other similar high boiling compounds.

It'will be understood that other addition agentsbesides the aluminum soaps may be added to the Diesel oils, such as oilness agents, corrosion inhibitors, oxidation inhibitors, extreme pressure agents, thickeners, dyes, etc;

The use of these soaps is not restricted to any particular type of non-waxy lubricating oil but is applicable generally to all Diesel lubricating fractions whether obtained bythe distillation, cracking, hydrogenation, destructive hydrogenation or other treatment of petroleum, coals, tars, shales, lignites or fractions thereof.

This application is a division of application Serial No. 181,374 filed December 23, 1937, now Patent 2,227,149, issued December 13, 1940.

This invention is not limited by any theories of the mechanism of the reactions nor by any details which have been given merely for purposes of illustration, but is limited only in and by the followingclaims in which it is intended to claim all novelty inherent in the invention.

I claim:

1. A composition comprising a polyvalent metal soap of acids derived from the oxidation of sweater oil.

2. A composition consisting essentially .of a polyvalent metal soap of acids derived from the oxidation of sweater oil."

3. A composition according to claim 2 in which the soap is prepared from a metal selected from the class consisting of aluminum, calcium, nickel, tin and magnesium.

4. A composition consisting essentially of an aluminum soap of acids derived from the oxidation of sweater oil.

5. A composition according to claim 2 in which the soap is prepared from an .acid fraction boiling between about C. and 280 C. at 4 mm. of mercury with steam, obtained from the products of oxidation of sweater oil.

6. A product comprising essentially a polyvalent metal soap of acids derived from the oxidation of a petroleum hydrocarbon fraction called sweater oil obtained as described in claim 8.

7. An oil-soluble, polyvalent metal soap of an acid fraction boiling between about 150 C. and 280 C. at 4 mm. of mercury with steam and having an acid number of about and a saponification number of about 240, said acid fraction being derived by subjecting to oxidation with air at a temperature between about 200 F. and 350 F. in the presence of an oxidation catalyst for a. period of about 2 to 4 hours, a petroleum hydrocarbon fraction called sweater oil obtained as described in claim 8. v

8. A productconsisting essentially ,of a polyvalent metal soap of acids derived by the oxidation of a. petroleum hydrocarbon oil fraction called sweater oil obtained by sweating oil out of a scale wax to make refined paraflin wax.

EGER V. MURPHREE.