US1694461A - Fatty acid and soap derived from mineral oil and process of making same - Google Patents

Description

Patented Dec. 11, 1928.

UNITED sTATEs PATENT OFFICE.

GELLERT ALLEMAN, OF SWARTH'MORE, PENNSYLVANIA, ASSIGNOR IO SUN 'OIII COM- -IPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

FATTY ACID AND SOAP DERIVED FROM MINERAL OIL AND PROCESS OF MAKING SAME.

No Drawing.

In the manufacture of lubricating oils ond distillate may then be redistilled, the part remaining also being adapted for lubricating stock. Lubricatingstock is usually treated with sulfuric or other suitable acid, with ag tation, forming an acid sludge, whlch 1s drawn off. After the sludge is separated from the lubricating stock, the latter is treated with caustic soda or any other alkali, forming a precipitate, which may be called soda sludge or alkali precipitate, whlch is drawn'off and usually allowed to go to waste.

It is known that this alkali precipitate con- 20 tains a fatty acid soap or organic acid soap,

:1, large proportion of mineral oil, a considerable'body of inert material similar to the fossil resins, which I hereinafter call'petroleum resins, some sodium sulfate, and more or less water. It is known to so treat this alkaline precipitate as to eliminate some of the mineral oil, a large part of the water and most of the salts, and'to materially reduce the percentage of mineral oil. However, no process has ever been devised to effect an absolute, or even a substantial, elimination of the mineral oil, except the process set forth in my application filed February 6, 1924, Serial No. 691,022; norhas any process been devised to separate the petroleum resins.

In other words, a mineral oil derivative soap that. is miscible in all proportions with water or mineral oil, that is not a sulfonic acid soap or a naphthenic acid soap and is adapted to undergo the character of hydrolytic decomposition that occurs with soaps of animal or vegetable origin, that is distinguishable from soaps of animal or vegetable origin in that it contains a substantial proportion of mineral oil and petroleum resins and a minute percentage (say .02 per cent) of sulfur, is known (see Maitland Patents 1,425,882 and 1,425,884) but no such product is known that is also'devoid of both mineral oil and petroleum resins; and no such product is known that is devoid of mineral oil except the product set forth in my said application.

,undergo the character of hydrolytic decomeral oil and petroleum resins. Such isolated Application filed July 18, 1925. Serial 110. 44,629.

So, also, it is known to provide a saponifiable mineraloil derivative, or fatty acid, that is not a. sulfonic or naphthenic acid, and which is a liquid practically odorless, insol- I uble in water and does not become rancid, and

which is saponifiable and when saponified 1s soluble or emulsifia'ble in all proportions with water and mineral oil and is adapted to position that occurs with soaps of animal and vegetable oil, and which isdistinguishable from soaps of animal or vegetable origin in that it contains a substantial proportion of mineral oil and petroleum resins as well as a minute percentage of sulfur (see Maitland patents aforesaid); but no such product is known that is also devoid of both mineral oil and petroleum resins; and no such product is known that is devoid of mineral oil except the roduct set forth in my said application.

T 1e object of my invention is to isolate the above described fatty acid and soap derived from mineral oil; or, more accurately stated, to produce -a fatty acid and a soap having the characteristics specified above as characterizing known fatty acids and soaps but which is substantially devoid of both minfatty acid product, as might be conjectured, I found to be a mixture of acids. The pre I ponderating proportion of these fatty acids have certain compositions and properties which, combined, characterize no known isolated fatty acid derived from any source whatever. i

In practicing my process, I may start with any composition derived from mineral oil and containing soap, petroleum' resins and .90 mineral oil, such as the alkali precipitate hereinbefore mentioned or the product of the Maitland patents specified. In giving a specific example of the process, it will be understood that the statements therein contained as to the precise details of treatment are predicated upon the treatment of a composition having definite proportions of certain ingredients and produced in the above described treatment of lubricating oil stock derived from Texas oil. It will also be understood that even with this particular crude pe-. troleum, different distillation processes, and even variations in the same distillation process, as well as variations in the crude oil, would yield alkali precipitates of varied compositions and characteristics, making advisable some variation from the specific example of the process herein given, in order to secure the elimination of the mineral oil and petroleum resins to the highest degree. The skilled operator, however, can readily adjust the factors to secure the main results sought, namely, the substantially complete elimination of the mineral oil and petroleum resins.

A typical soap emulsion (e. g., alkali precipitate or soda sludge) from which I have succeeded in eliminatin the mineral oil and petroleum resins, is as ollows:

Per cent. Soap 11.6 Petroleum resins 17 .1 Mineral lubricating oil 46. Sodium sulfate 2.3 Water 23.

The soap, oil, and water emulsion, or colloidal suspension, contains particles or droplets which are positively charged. If this mixture is treated with gasoline, practically no separation takes place, except after very long standing. If, however, a small amount of ,lithium sulfate, sodium sulfate or potassium sulfate, or a small amount of lithium chloride, sodium chloride, or potassium chloride is added to the suspension or emulsion in gasoline, an immediate separation takes place. The sulfates are found to be superior to the chlorides, the double negative charge on the sulfate ion being more effective than the single negative charge on the chloride ion in neutralizing and precipitating the positively charged emulsion particles. Lithium salts are superior to sodium salts, and sodium salts superior to those of potassium. This is a function of surface tensionlithium increasing surface tension more than sodium or potassium, and hence tending to break the emulsion more readily. From a commercial standpoint, sodium chloride (common salt), becauseof its abundance and low cost, seems to be the most desirable substance to effect the separation of the gasoline and oil, withdissolved resins, from the soap, water and a minor proportion of resins. A saturated solution of the .salt is used, being added to the amount of 10 per cent of the total volume. The salt solution may be added before the introduction of the asoline or it may be added after the gaso ine has been distilled into the soap-oil-water emulsion. Instead of using a saturated solution of salt in water, solid sodium chloride (salt) may be added.

It is best to allow the gasoline to enter the crude soap tank, at the bottom, as a vapor. This stirs the mixture, and probably also aids in neutralizing the electrical charges on the suspended colloidal particles. Larger surfaces are exposed to the gasoline, in this manner.

The apparatus employed is conveniently arranged as follows: An upright, cylindrical container is employed to hold the oil-soapwater emulsion, which should fill the container to about one-third its capacity. This is conveniently connected to a gasoline still. The bottom of the first mentioned container should be above the level of the gasoline still. Vapors of gasoline are passed through appropriate pipes, from the still, to the bottom of the container holding the soap-oil-water emulsion. To the emulsion is added a saturated solution of common salt, equivalent in volume to about one-tenth of the soap-oilgasoline emulsion. Gasoline vapor is introduced at the bottom until the container is almost filled by the condensed gasoline. The introduction of gasoline into this container is then discontinued and the mixture allowed to separate. The gasoline-oil layer on top is siphoned back into the-gasoline still and the process repeated. After about three extractions, the soap-water solution which remains in the bottom of the container is substantially free of mineral oil, but contains the petroleum resins that have not been dissolved by the gasoline.

The partially purified soap contains the original sulfur compounds, wholly or principally sodium sulfate, which were In the crude soap. These can be largely removed by known methods if their removal be desirable. For example, the soap solution may be concentrated by first evaporating some of the water (to expedite the operation) and then cooling in order to separate the soap from the sodium sulfate, which remains in solution in the water. The separation begins to take place at about5 C. and is hastened by lower temperatures. The sodium sulfate remains in solution in the water.

The soap has the characteristics hereinbefore described as characterizing a known product, i. e. that of the Maitland patent specified, but has the further characteristic n that it is devoid of mineral oil and of the majof part of the resins. If it is desired to convert the soaps into fatty acids it may be so converted bymeans effective to convert other soaps into fatty acids, as, for example, 5 by decomposing the soap with sulfuric, hydrochloric or other mineral acids. These fatty \acids have an acid number of about 103.55 (The original crude soap before treatment yields fatty acids having an acid number of 30.) j-

The fatty acids are now subjected to distillation at an absolute pressure of 4 mm. of mercury yielding distillates which are free from resins. Up to a temperature of 180. C. a fraction is obtained having an acid number of 187.06. The next fraction boiling off between 180 and 190 C. has an acid number of 174.4. The next fraction boiling ofl' between 190 and 200 C. has an acitl'nu'mber 13c of 160. The residue, containing most of the resins, present before distillation, has an acid number of 61.

Any of these fractions may be, of course, saponified by the addition of any agent adapted to saponify fatty acids. If the fatty acid having an acid number of 103.5 is so treated, it of course, produces a soap the same as that from which the fatty acid was directly derived by decomposition with a mineral aci My improved fatty acids differ from ordinary fatty acids of animal or vegetable origin having chemical compositions and molecular weights approximating those of my im-' proved fatty acids in that they are liquid at ordinary temperatures arid solidify only at very low temperatures, differ in refractive index and by their degree of volatility (distilling temperature under a vacuum), and do not dry or harden when exposed to air but remain sticky or tacky indefinitely. At any rate, they haverbeen exposed to observation for a period of eighteen months and still retain this quality.

In order to more particularly differentiate my improved fatty acids from known fatty acids, the following more specific informa tion regarding the compositions, qualities, and properties of the same are given.

1. A predominating proportion of the acids belong to the series C H O and G H O One acid out of eleven that have been isolated from the mixture of acids seems to belong to the series C H O 2. They do not absorb oxygen from the air, and do not dry, or harden.

3. They have an extremely low melting point (below minus 30 C.)

4. They are extremely viscous at low temperatures and will not flow at 0 C.

5. The salts of all the acids are soluble in gasoline, in ether, and in carbon tetrachloride. The lithium, ammonium, potassium, sodium, and magnesium salts are soluble in water.

6. The acids cannot be distilled at ordinary atmospheric pressure without decomposition.

7. At an absolute pressure of 4 millimeters of mercury, the acids volatilize at temperatures ranging between about 160 C. and 245 C.

8. They have an extremely high refractive index. This ranges between 1.48563 and 1.49654. Only two of these acids have a refractive index below 1.49, and only one has a refractive index below 1.48968.

9. They are not volatile with steam ;.that is, when the materials are heated to a temperature above the boiling point of water but to a temperature below the point at which they will volatilize, and steam is passed through the materials, at the bottom of the container. the fatty acids will not pass over with the steam.

- 10. Their carbon content ranges froni C to C that is, there are from 16 to 25 carbon atoms in a molecule of the acid.

11. Their molecular weight ranges from about 250 to about 376. p a I 12. The saponificat-ion numbers obtained indicate that there is but one carboxyl group present.

.13. They latter belong to the series C H O 14. They do not give the reactions of ketonic acids.

In place of using gasoline in the manner described, I may use any light hydrocarbon, whether derived from petroleum or other sources, such as a benzol distillate from coal tar. Y

are notnaphthenic acids, which" It is not my intention, however,- to limit the product herein claimed to a product produced by the described process,'inasmuch as other methods of producing the fatty acids described may be devised. The described method, however, is particularly advantageous, particularly in respect to its simplicity and economy, and is entirely eflicient to effect the desired isolation of the fatty acid soap, from which all mineral oil and petroleum resins may be practically completely eliminated by practicing the described process in a thorough and careful manner.

Where, in the claims, I refer to soap or fatty acid substantially free of resins, I do not mean to be confined 'to a product from which the resins are necessarily completely eliminated. The fact that resins are present in the residue from the distillation indicates their presence, in small proportiomin the fatty acids before distillation. It isobvious that the advantages of my new product are 1 present, to a substantial'degree, even though J I the original content of resins 1S very greatly v reduced rather than absolutely eliminated.

Having now fully described my invention, what I claim and desire to protectby Let tors-Patent is: i

1. As a new product, a mixture of fatty acids derived from mineral oil, the same being insoluble in water and readily saponifiable, and when saponified being miscible. in all proportions with mineral oil and water and when mixed with oil and water forming a, homogeneous emulsion and having essential characteristics of soaps of animal or vegetable origin in that it forms with water a similar emulsion and undergoes the same character of hydrolytic decomposition; the fatty acids being distinguishable from othe. saponifiable derivatives of mineral oil in that in addition to the characteristics Specified they are substantially free of mineral oil and petroleum resins, and being distinguishable from fatty acids of animal or vegetable origin in that they have a melting range. below minus 30 C. v

2. As a new product, a mixture of fatty range below minus 30 0.

acids derived from mineral oil, the same being substantiall free from petroleum resins and mineral oi, and a preponeratmg proportion of which have the generic formulae C H O, and 0,,H and a melting volatilize at an absolute pressure of four mil- *limeters mercury at temperatures ranging between about 160 0. and about 245 0.,

have refractive indices mostly above 1.49,

have carbon contents the molecules of which contain from 16 to carbbn atoms and molecular weights ranging from about 250 to about 376.

4. As a new product, a derivative from mineral oil, the same being a soap miscible in all proportions with water and mineral oil, and when mixed with mineral oil and water forming a homogeneous emulsion, and having essential characteristics of soaps of animal and vegetable origin in that it forms with water a similar emulsion and undergoes the same character of hydrolytic decomposition; the new product being distinguishable from soaps of animal or vegetable origin in that the fatty acids from which the soap is derived have a melting range of below minus 0. and being distinguishable from other soaps derived from mineral oil in that in addition to the characteristics specified it is substantiall free of both mineral oil and petroleum reslns.

5. As a new product, a mixture of fatty acids derived from mineral oil, the same bein insoluble in water and readily saponifia 1e, and when saponified being miscible in all proportions with mineral oil and water and when mixed with oil and water forming ,a homogeneous emulsion and havin essential characteristics of soaps of animal or vegetable origin in that it forms with water a similar emulsion and undergoes the same character of hydrolytic decomposition; the fatty acids being distinguishable from other saponifiable derivatives of mineral oil in that in addition to the characteristics specified their acid number is not below about 100, and being distinguishable from fatty acids of animal or vegetable origin in that they have a melting range of below minus 30 0.

6. A soap derived from mineral oil and comprising a saponified mixture of fatty acids having an acid number not below about 100 and a melting range of below minus 30 0., the soap being miscible in all. proporof hydrolytic decomposition; I

7. As a newproduct, the. hereinbefore de-' scribed mixture of fatty acids derived from 0., 0 not absorb oxygen from the air, cannot be distilled at at-' mospheric pressure without decomposition,-

tions with mineral' oil and water and when mixed with oil andfwater forming a homogeneous emulsion and hav' teristics of soaps of anima or vegetable'origin in that it forms witkwaler a similar emulsion and undergoes the. same character mineral oil, the same being insoluble in water and readilysa onifiable, and when saponified bein with mineral oi and water and when mixed with oil and water forming a homogeneous emulsion and having essential characteristics of soaps of animal or vegetable'origin in that it forms with water a similar emulsion and undergoes the same character of hydrolytic decomposition; the fatty acids'being distinguishable from other saponifiable derivatives of mineral oil in that in addition to the characteristics specified their acid number is not below about 160, and being distinguishable from fatty acids of animal or vegetable origin in that they have a melting range of below minus 30 C.

8. A soap derived from mineral oil and comprising a saponified mixture of fatty acids having an acid number not below about 160 and a melting range of below minus 30 0., the soap being miscible in all proportions with mineral oil and water and when mixed with oil and water forming a homogeneous emulsion and havin essential characteristics of soaps of anima or vegetable oriemulsion and undergoes the same character of hydrolytic decomposition.

9. As a new product, a mixture of fatty acids derived from mineral oil, a preponderating proportion of which have the generic formulae C H O and 0n H O and have a melting range below minus 30 degrees 0. and are so nearly pure that their acid num ber is not below about 100. V

10. As a new product, a soap comprisinga saponified mixture of fatty acids as specified in claim 9.

11. As anew product, a mixture of fatty acids derived from mineral oil, a preponderating proportion of which have the generic formulae 0,,H,,, ,O and CDH O and having a melting range below minus 30 degrees 0., and are so nearly pure that their acid number is not below about 160.

,12. As a new product, a'soap comprisin a saponified mixture of fatty aclds as speci ed in claim 11 13. The process of recovering fatty acids from a crude soap emulsion containing soap,

mineral oil, petroleum resins and water which comprises adding to the crude soa emulsion a water soluble salt in quantity su ficient to enable the hereinafter specified sepessential characmisci le in all proportions contact therewith, the gasoline dissolving the oil, separating the solution of gasoline and such of the resins as are dissolved therein from the soap, converting the soap into fatty acids, and by distillation separating the fatty acids from any of the resins-that have not dissolved in the gasoline In testimony of which invention, I have hereunto set m hand, at Swarthmore, Pennsylvania, on thls 10th day of J uly, 1925. v

1 GELLERT ALLEMAN.