US2178769A - Voltolization of mineral oils and products thereof - Google Patents

Description

Patented Nov... 7

sires argues OFFICE V VOLTOTIUN OF MINE UELS PRODUCTS THEREOF Peter J. Wiezevich, Elizabeth, H. .lL, now by'ju-' dicial change of name to Peter J. Gaylor, as-

signor to Standard Oil Development Eompany, a corporation of Delaware No Drawing.

1 5 Claims.

Application January 111, 1936, Serial No. 58,780

cosity, has already been suggested. Such treatment may be conducted in any suitable apparatus for bringing the oil in contact with a silent electric discharge. It is conveniently conducted in a Siemens ozonization tube or in a trommel type voltolizer, in which a thiniilm of oil is continuously passed between electrodes in a reaction chamber maintained under an absolute pressure or about 2 to or cms. of mercury, with an electric potential of about 1,000 to 10,000 volts or more at a frequency of'about 500 to 10,000 cycles per second, the potential and pressure and space between electrodes being adjusted so as to 'obtain continuous silent electric discharge.

rates are the highly refined white oils produced by the action of fuming or concentrated sulfuric acid, and also destructively hydrogenated oils or oils prepared by strong hydrogenation at low temperatures. The rates of oxidation of well re- 5. lined oils of the types mentioned above may be far in excess of the figure mentioned, for example, they may have absorption rates up to 100 or 180 or even up to 300 cc. for very pure parafm iinic oils.

It has now been found that greatly improved products, are prepared by submitting non-paraffinic concentrates of mineral oils, particularly oils boiling above about 400 F. and preferably lubricating oils, to such treatment with the silent electric discharge. By this means oil fractions oi poor color, from a lubricating oil standpoint, are converted into improved lubricating oils of a color and cast equal to that of high grade Pennsylvania lubricating oils.

The voltolized products of this invention are also very resistant to oxidation, and may be used as oxidation inhibitors in other oils, such as petroleum lubricating oils generally. They are particularly suitable for addition in small amounts of about l, 2 to 5 or 10% to refined petroleum lubricating oils which have a high rate oi oxidation.

By an oil of high oxidation rate is meant an oil which has an absorption rate in excess of about cc. of oxygen per fifteen minute interval per 10 cc. of sample when agitated with oxygen at a temperature of about 392 F. Examples of such oils are those which are substantially parafiinic in type, such as those obtained from paramn or mixed base crudes which have been well refined with acid, clay or by other means so The voltolized non-paraflinic concentrates also have the property of reducing the pour point of waxy lubricating oils, when added thereto in small amounts of about to 10% and preferably of the order of 1 or 2 to 5%. 154

The non-parafiinic concentrates suitable for use according to the-present invention are fractions, preferably oils composed predominately of unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, naphthenic hydrocarbons, and/or asphaltic compounds isolated from paramnic hydrocarbons in mineral oils and which are separated from mineral oils by any suitable .means for separating the parafiinic and non-parafiinic components thereof. A preferred method is by extracting the oil with a solvent having a selective solvent action between the parafiinic and the non-parafiinic components. The solvent may selectively dissolve the paramn, or it may have a preferential solvent action on the aromatics, olefins, naphthanes, and/or asphaltic components, separately or collectively, of the oil. Examples of suitable selective solvents are liquid sulfur dioxide, phenol, wet phenol, cresols, acetone and other ketones, benzol-acetone mixtures, liquid sulfur dioxide, benzol mixtures, nitrobenzol, furfural, the lower aliphatic alcohols, dichlorethyl ether, ethylene dichloride and other halogenated light hydrocarbons of about 2 to 4 carbon atoms, esters, ethers, aldehydes and ketones generally, the normally gaseous liquefied hydrocarbons, as of 2 to 4 carbon atoms per molecule, propane-phenol mixtures and other mixtures of liquefied normally gaseous hydrocarbons with selective solvents for naphthet c or aromatic hydrocarbons. These solvents may be used alone or in various combinations, for batch, continuous and countercurrent extraction according to the usual methods for the solvent extraction of the lubricating oils and burning oils.

The non-paraiiinic concentrates are preferably normally liquid oils having a viscosity above about 10 to 50 seconds Saybolt at 210 F. Highly viscous to normally solid concentrates, of asphaltic consistency, may also be used, and are preferably voltolised at a temperature at which they are liquid, or are dissolved in any suitable solvents. By the action of silent electric d charge, the non-paraffinlc compounds are polymerized to viscous oils having viscosities above Lilli) Saybolt seconds at 2lil preferably above 3.000 Saybolt seconds at 210 and the thus formed polymerization product is characterized by possessing efiective oxidation inhibiting properties when dissolved minor proportions in refined petroleum lubricating oils.

lit has been found that the addition of small amounts of sulfur, of the order of about 0.1 to 2% or more, to the concentrate before the voltolization substantially increases the effectiveness of the voltoiized product an oxidation inhibitor in refined oils. This sulfur is preferably dissolved in the oil, but oil-soluble sulfur compounds, preferably non-acidic organic compounds, may be dissolved in the oil, or flowers of sulfur may even be mixed with the oil prior to voltolization. One suitable method for dissolving sulfur in the oil is by heating a mixture of the oil and flowers of sulfur to a reaction temperature of about 300 F., whereby the sulfur reacts with the oil to form oil-soluble organic sulfur compounds.

-1e ncn-paraffinio concentrates may also be mixed with other oils prior to or during the voltolization. Such oils include mineral oils, which are preferably less paramnic than the oil from which the extract was obtained, also oxygen-contaming oils such as the natural and synthetic estors, including animal, vegetable and fish oils. Unsaturated oils having iodine value of about 58 to 100 are preierable for such use, but more and less unsaturated oils may also be used.

following eramples are presented to illustrate suitable methods for conducting the process of the present invention, but are not to be construed as limiting this invention in any way.

Example I A lubricating oil having a viscosity of 95 seconds Saybolt at 210 F. was obtained by distillation of a Mid-Continent crude petroleum. This oil was extracted with about 2 volumes of phenol at 175 F., thereby obtaining 32% of an extract which, after distilling ofi the phenol, had a viscosity of 331 seconds at 210 F., a density of 1 12.0" A. P. I. and a dirty green-black color.

This extract was mixed with an equal volume of rapeseed oil, and the blend was then subjected to the action of a silent electric discharge in a trommeZ-type voltolizer for 28' hours, at an absolute pressure of l to 6 mm. of mercury and at an elec-.

trio potential of 25G0-volts at 10,000 cycles per second. There was thus obtained as condensation product an oil having the clear green cast and appearance of a high grade Pennsylvania oil,

a viscosity of 159% seconds at 210 5.

Example .al

in Example 15, was sulm1 extract, obtained inhaled by mixing therewith 0-.6% by Weight of flowers of sulfur heating to scar e sub furized extract then blended with on. equal $aybolt viscc ,ivavco raise the vis- This is amounts of about or more to cosity and improve the viscosity index. illustrated in the following example:

Example III 10 volumes of the two condensation. products obtained in the above examples were each blended with 90 parts ole petroleum lubricating oil. "l'he viscosities of the original oil and the blends were as follows:

+107 of con- -1O% of condensz te from dcnsetc from Example I Example II V iscosltySaybolt:

Seconds at 100 F... 169 278 274 Seconds at 210 F... 44. 9 54. 2 53. 6 Viscosity index 99 120 119 These condensation products may also be used as oxidation inhibitors for lubricating oils, and

,are particularly suitable for use in stabilizing highly refined lubricating oils which have high rates of oxidation. This is illustrated in the following example:

Example IV distillate'having a viscosity of about 50 seconds at 210 F. and without the addition of non-parab finic concentrates. The oxidation characteristics of the original oil and the blends were determined by measuring the volume of oxygen absorbed in a fixed time while passing oxygen over the SUI-- face of a standard volume of oil heated to 392 F. under carefully standardized conditions. The results obtained are presented in the following table:

Percent Oxidation Voltohzed condensate in on mm in oil 0.0 84 Rapeseed-mineral oil 2. 0 09 Example In"; 2.0 39 Example I 5. 0 19 Example II 2.0 14

Example V A west Texas burning oil fraction was extracted with liquid sulfur dioxide, yielding an extract, which was destructively hydrogenated over a sulfur resistant catalyst under conditions, adapted to the formation of anti-knock gasoline, at a temperature of the order of 900 to 110W F. and a pressure above 20 to 50 atmospheres, preleraoiy about 100 to 200 atmospheres, with a partial pressure of free hydrogen or" about half the total pressure. 49 parts of the highly aromatic distillation idue of this destructively hydrogenated pro ct were mined with 49 parts of a Mid-Continent lubricat' stillate of i2 seconds -ty at 3'10 which had been relined by hydrogenation and acid and clay treating. 2 parts of flowers of sulfur were mixed with this'blend, and the mixture was heated to 3% F. to dissolve and fix the sulfur.

This sulfurlzed blend, having a viscosity of 32 seconds at Zl0 ill, was then subjected to the action of the silent electric discharge in a Siemens ozonizer tube in an atmosphere of hydrogen at 2 cm. of mercury absolute pressure, at an electric potential of 3000 volts and a frequency of 1200 cycles per second. The resulting voltolized product had a viscosity of 68 seconds at 210 F. of this product was added to a light phenolextracted Mid-Continent petroleum oil having a viscosity of 48 seconds at 210 F. and an oxidation rate of 70. The oxidation rate of. the resulting blend was thereby reduced to 32.

The addition of ordinary, unvoltolized nonparafinic concentrates, such as phenol extracts,

to refined lubricating oils, such as those shown in the above examples, results in blends of poor quality for motor lubrication, because they deposit much sludge on oxidation. The blends prepared with voltolized products, as in the above examples, are much superior in that this tendency to deposit sludge is greatly reduced.

This application is a continuation-in-part of my copending application Serial No. 751,706, filed November 6, 1934.

This invention is not to be limited to any examples or explanations, all of which are presented herein solely for purpose of illustration, but is limited only by the following claims, in which it is desired to claim all novelty insofar as the prior art permits.

'1 claim: 7

1. A process of preparing an anti-oxidizing hydrocarbon composition for use in lubricating oil, which comprises treating crude petroleum oil with a selective solvent to remove the non-paraffinic components, thereby obtaining a parafiinfree oil containing aromatic, olefinic, naphthenic,

the treated oil to silentelectric discharge polymerizatlon, thereby obtaining a polymerized hydrocarbon' oil having high oxidation resistance properties.

2. A process of preparing an anti-oxidant blending agent for use in a refined petroleum lubricating oil, which comprises selectively extracting a high boiling crude petroleum oil with a solvent which preferentially dissolves cyclic and unsaturated hydrocarbons, and then subjecting the resultant parafifin-free concentrate to silent discharge polymerization, thereby obtaining a polymerized hydrocarbon oil having oxidation inhibiting properties. v

3. A process according to claim 2, in which said non-paraffinic concentrate is polymerized with dissolved sulfur by the action of the silentelectric discharge.

4. A process according to claim 2, in which said non-parafilnic concentrate is polymerized with an unsaturated ester oil by the action of the silent electric discharges.

5. An anti-oxidant. blending agent for use in refined petroleum lubricating .oil, which comprises a viscous silent electric discharge polymerization product of a non-parafiinic solvent extract from a crude petroleum oil, said polymerization product being characterized as consisting essentially of polymens formed by mixed cyclic and unsaturated hydrocarbon high boiling petroleum components in the absence of parafinic petroleum components, by having a viscosity above 1000 Saybolt seconds at 210 F., having miscibility with refined petroleum lubricating oils, and by having ability to reduce the oxidation rate' of refined petroleum lubricatin'gails.

PETER J. "WTIEZEV'ICB.