US2671753A - Recovery of oxidation inhibitors - Google Patents

Description

March 9, 1954 J. G. LlLLARD RECOVERY OF OXIDATION INI-IIBITORS Fired oct. 19, 195o 2 Sheets-#Sheet l ALCOHOL STORAGE 'ATE R TE TRHYOROFUIFURYL ALCOHOL INTERUEOITE EXTRAOT INVENTOR. James 6. Lil/ord,

March 9, 1954 A 1 G, ARD 2,671,753

RECOVERY OF OXIDATION INHIBITORS l Filed Oct. 19, l1950 2 Sheets-Sheet 2 OXID TION v INHIBITUR ll-LIGHT SOLVENT il M l TETRAHYDRUFURFURYL I4 ALCOHOL STORAGE j ACETONE STORGES' sPEfH'V nu su meren 124 Llenr "2' saLvsNr f iI f | serrLsn 122 i l 5 N20 J2 WA TER FRGTION INVENTOR. James G. Lil/ard,

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ATTORNEY.

Patented Mar. 9, 1954 `UNITED STATES PATENT OFFICE RECOVERY OF OXIDATION INHIBITORS James G. Lillard, Baytown, Tex., assignor, by

mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application october 19, 195o, serial No. 190,915

7 Claims.

The present invention is directed to a method for recovering an oxidation inhibitor from solvent extracts of lubricating oil fractions. More particularly, the invention is directed to the production of an oxidation inhibitor from a solvent;

fraction, for example, a Mid-Continent lubricating oil fraction, with a solvent comprising tetrahydrofurfuryl alcohol or with a solvent comprising tetrahydrofurfuryl alcohol and acetone. The phenol extract is admixed with the tetrahydrofurfuryl alcohol solvent under conditions to provide a ratio of tetrahydrofurfuryl alcohol to solvent extract in the preferred range between 1:1 and 4:1. A small amount of water, such as up to about 3% based on the solvent may be added to increase the solvent selectivity. At temperatures in the range from 20 to 100 C. and at pressures ranging from to 25 pounds greater than the vapor pressure of the solvent, the admixture of the solvent extract and solvent forms stripping of the solvent from the hydrocarbon extract phase. The solvent-free hydrocarbon extract phase recovered by either of the above procedures is then suitable for use as an oxidation inhibitor. The oxidation inhibitor may suitably be added to oxidation susceptible lubricating oil fractions such as those obtained from Coastal crudes and those having a naphthene base.

The present invention will be further illustrated by reference to the drawing in which:

Fig. I is in the form of a diagrammatic iiow sheet illustrating one mode of practicing the present invention and Fig. II is in the form of a ow sheet illustrating another mode of practicing the present invention.

Referring now to the drawing, and irst to Fig. I. numeral I I designates an extraction zone which is designed to allow countercurrent extraction of hydrocarbon oils. Extraction zone II is understood to include internal baling equipment such as bell cap trays and contact equipment to allow intimate contact between immiscible liquids. It will be understood that extraction zone Il is also provided with means for inducing reflux such as are well known in the solvent extraction art. Leading into extraction zone Il is line I2 by way of which there is introduced thereto a feed which for the purposes of this description is a, phenol extract of a Mid-Continent lubricating oil fraction. At times it may be desirable to admix the feed with a paraiiinic hydrocarbon before it is introduced into the extraction zone, and such a vlight hydrocarbon may be introduced through iniet line IIJ into the feed passing through line I2. Where a phenol extract of `MidContinent lubricating oil fraction is used as feed, the par'- aiiinic hydrocarbon may be added thereto in an amount within the range from 10% to 150% based on said phenol extract. There is introduced into extraction zone Il from storage tank I 3 tetrahydrofurfuryl alcohol which is discharged from tank I3 by line I4 and thence by line I5 into extraction zone II. Conditions are adjusted in extraction zone il to maintain a temperature in the range between 20 and 100 C. such that a liquid phase is maintained therein. Pressure may be in the range from 0 to 25 pounds greater than the vapor pressure of the tetrahydrofurfuryl alcohol. Under the conditions in extraction zone I I, which preferably includes the maintenance oi a tetrahydrofurfuryl alcohol to phenol extract ratio in the range between 1:1 and 4:1, there is formed therein a raiiinate phase and an extract phase. The extract phase by virtue of the nature of the tetrahydrofurfuryl alcohol separates in the lower portion of zone II and there may be admixed therewith by way of line I6 controlled by valve I'I a small amount of water such as up to about 3% by volume based on the original tetrahydrofurfuryl alcohol. The water-containing extract discharges from extraction zone Il by line I8 and may be introduced thereby into a solvent stripping zone I9 which is provided with a heating means illustrated by steam coil 20 wherein temperatures and pressure are adjusted therein to allow the removal from stripper I 9 of water by line 2l and tetrahydrofurfuryl alcohol by way of line 22 which returns the tetrahydrofurfuryl alcohol to storage tank I3. The oxidation inhibitor is withdrawn from stripper I9 by line 23 for addition to lubricating oils susceptible to oxidation. Stripping zone i9 is preferably operated at reduced pressures as low as l0 mm. mer- .eury absolute to prevent alcohol degradation.

The ranate phase from extraction zone H discharges by line 24 controlled by valve 25 into a stripping still 26 which is similar to stripping still I9 and is provided with a heating means illustrated by coil 21 wherein conditions are adjusted in stripper 2S to remove overhead therefrom water by line 23 and as a side stream tetrahydrofurfuryl alcohol by line 29 which connects into line 22 and allows return of the tetrahydroi'urfuryl alcohol to storage tank I3. The stripped` raffinate discharges from stripper 25 by line 33 controlled by valve 3! into line 32 and` thence intol a second extraction zone 33 wherein the raiiinate is subjected to re-extraction with acetone introduced thereto by line 34 from. acetone storage tank 35.

Extraction zone 33 is similar to extraction zone Il and is provided with contacting equipment to insure intimate contact between inimiscible liquids. Extraction zone 33 is also provided with means for inducing refiux therein. The temperature conditions in extraction zone 33 are. in the range between U and' 75 C. while pressures may range from 0 to 30' pounds per square inch gauge. The amount of acetone which is em'- ployed to contact the raihnate in extraction zone 33 may range from a ratio of l to l to d' to. l of acetone to raffinate. Under conditions obtaining in extraction zone 33 a second ramnate and a second extract phase are formed'. The second.- ary extract is withdrawn from extraction zone 33 by line 35 controlled by valve 3l* and introduced thereby into a stripping still 38 which, similar to stripping stills i3 and 33, isV provided with a heating unit. illustrated by coil 39 wherein temperature and pressure conditions are maintained to remove overheadV byY line 43 which connects into line 4I acetone which is returned; by line di and branch line 42 to acetone storage The stripped secondary extract discharges from stripper 38 by line 43 controlled by valve 44 and may be recycled to line I2 by way of line 43 controlled by valve 46 orV may be discharged in part by opening valve 4T forV withdrawal ofthe intermediate extract froxn the system.

Alternatively, the extract withdrawn by line 36 from extraction zone 33 may by-pass stripper 33 by closing valve 3'! in line 33 and thus allowing the extract to be routed by line 48 controlled by valve 43 to line 43 and thence by line 45 for admixture with the phenol extract in line i2.

The rainate from secondary extraction zone 33 discharges therefrom by line 53 and is introduced thereby into a stripping zone I which, similar to the other stripping stills, is provided with a heating means illustrated by steam coil 52 for adjustment of temperatures and pressures therein to allow removal from stripper 5I by line 4I acetone which is discharged by lines I and 42 into acetone storage 35. Since the ramnate withdrawn from extraction zone II and second extraction zone 33 contains tetrahydrofurfuryl alcohol, the acetone stripped raffinate is discharged from stripper 5I by line 53 and routed by line 54 controlled by valve 35 into stripping zone 56 which is similar to the other stripping zones and is provided with a heating means illustrated by a steam coil 57 to allow recovery of the tetrahydrofurfuryl alcohol from the raffinate by line 53 which connects into line 22 and conducts the tetrahydrofurfuryl alcohol back to storage tank i3 for re-use in the process. rEhe stripped rainate is withdrawn from stripper 53 by line 53 controlled by valve 30 for use as may be desired.

As an alternative mode of practicing the invention, a mixture of tetrahydrofurfuryl alcohol and acetone may be employed as a solvent. Under these conditions the ratio of tetrahydroiurfuryl alcohol to acetone may range up to equal volurnes of tetrahydrofurfuryl alcohol to acetone. For purposes of this description it is assumed that an equal Volume mixture of tetrahydrofurfuryl alcohol', and acetone is introduced into extraction zone II by way of line I5, the acetone being withdrawn from storage tank 6I by line 62 controlled by valve 63. It is to be understood `that instead of providing an extra storage tank 6I for acetone that storage tank 35 may be used therefor, but for purposes of this description two storage. tanks are provided. In this operation the fiow is identical to that described before with the exception that the extract withdrawn by line I8 is discharged by branch line 64 controlled by valve, 65A into stripping zone 63 which, like the other stripping zones, is provided with a heating means illustrated by steam coil 6l' for adjustment of temperature and pressure conditions therein. When this mode is employed, it isv understood, of course, that valve 63 in lineV Wis in a closed position. Removed overheadfrom stripper 55 by line 69 is a stream of acetone which is discharged into storage tank 35 by way of line 42. The acetone-free extract is withdrawn from stripper 66 by line 'E3 controlled byY valve- T'I into line i8 and dischargedv thereby into line F3" for removal of water and tetrahydrofurfuryll alcohol as has been described, and forV recovery of the oxidation inhibitor by line 23.

The rafnate may be withdrawn from extraction zone II by line 24 and discharged into line 32 for introduction into second extraction'zone 33 as has been described, stripping zone 2I5v being by-passed by closing oii` valve 25 inline 24 and valve 3l in line 33, valve 'I2A in line 32 being opened to allowv passage of the rafilnate directly into extraction zone 33. The ow thereafter is identical with that described before with the extract either lay-passing stripper 38 or flowing by line 48 and line 43 and thence by line 45 back into feed line I2.

Although stripping techniques are generally preferred for separation of hydrocarbon extract and solvent, water washing procedures may be employed. The solvent extract, for example. may be admixed with suiiicient water, such as 15% or higher based on the extract phase to cause separation of hydrocarbon and solvent. rThe hydrocarbon layerl after separation, may be water washed to remove traces of solvent remaining therein;

Referring now to Figure II, another mode for practicing the present invention is here illus'- trated.

Irl Fig. II, extraction zone III corresponds to extraction zone II of Figure I. Storage tank I3, used for storing tetrahydrofurfuryl alcohol, and storage tank 62, used for storing acetone, and the lines I4, I5, S2 and valve 63 are identical to the corresponding units of Fig. I. Feed, such as a phenol extract of a Panhandle medium motor distillate, is introduced by inlet line II2 into extraction zone IH. In extraction zone III, a. raffinate phase and an extract phase are formed, the extract separating tothe lower portion of zone I II and being withdrawn through line IIB, while the raiiinate phase is withdrawn from extraction zone HI through outlet line I24. Into the stream of extract phase in line IIB there is introduced a low viscosity para'inic solvent by means of inlet line I I 4.1 The parafilnic' solvent is added'inv an amount sumcient to reduce the The aqueous alcohol layer is with- The hydrocarbon layer is withdrawn from settler |23 through` line |25 and passed into vessel |25, where it is washed with water introduced through inlet line |21 with a spent Wash water withdrawn through outlet line |28. The washed hydrocarbon is then passed from washing vessel |25 through line |29 to still |30 where the low viscosity paraiiinic solvent is removed as overhead through line |3| and the oxidation inhibitor is withdrawn through line |32.

It will be understood that various types oi auxiliary equipment, for example, such as that required for the recovery of solvent, will be desirable in the operation of the method illustrated in Fig. II, but for the purpose of simplifying the drawing and the description, such equipment has not been shown.

From the foregoing description and drawing, it will be seen that several modes of operation are provided wherein an oxidation inhibitor may be recovered by extracting a solvent extract of a lubricating oil fraction with tetrahydrofurfuryl alcohol.

The invention will be further illustrated by the following runs: In the first run 450 volumes of a lphenol extract of dewaxed Panhandle medium motor distillate were admixed with approximately equal Volumes of tetrahydrofurfuryl alcohol at 24 C. and at atmospheric pressure. Under vthese conditions an extract layer was separated and diluted with approximately equal volumes (500 parts) of a paraflinic solvent such as petroleum ether to reduce the viscosity of this layer. Water was then added to the admixture of extract and paraffnic solvent in an amount of approximately based on the extract layer. 'Ihe purpose of the addition of water was to reduce the solvency of the tetrahydrofurfuryl alcohol in the hydrocarbon and cause phase separation. The resulting hydrocarbon layer was then removed, washed with water several times to remove all the tetrahydrofurfuryl alcohol, dried and then distilled to strip therefrom the petroleum ether. Approximately llvolume per cent of an oxidation inhibitor was recovered. Physical and chemical inspection of the phenol extract charged to the operation and the raffinate which was recovered by water washing, drying and stripping similar to the aforementioned technique is compared in the following table with the characteristics of the tetrahydrofurfuryl al- A 6. From the foregoing inspection characteristics it will be seen that the tetrahydrofur'furyl alcoholv extract has a much higher carbon-hydrogen weight ratio than either the phenol extract charge stock or the raiiinate therefrom.

Various amounts of the tetrahydrofurfuryl alcohol extract were then added to an unstable Coastal lubricating oil and the blends were oxid-l ized under identical conditions in an accelerated laboratory oxidation test. The relative increase in viscosity was taken as a measure of degree of oxidation. The data obtained on these oxidation runs are shown in comparison with similar data. obtained for blends of the unstable Coastal lubricating oil with the original phenol extract charge stock and with silica gel extracts of the phenol extract in varying percentages. An oxidation index, which is the product of the ratio of the per cent viscosity increase of the sample to therper cent viscosity increase of .the standard times 100, was calculated for each sample for obtaining relative oxidation characteristics. A lower oxidation index indicates greater resistance to oxidation. These results are given in Table II:

Table II Viscosity at F. Percent Oxidw Additive and Concentration Iirxllcssf tion 2 Initial Oxicosity Index dized None (Standard) 577 1, 650 186 100 5%-Total Phenol Extract 615 950 55 30 2%-20.6 to 20.9 1 -A 577 l, 579 173 93 2%-55.8 t0 57.1 577 1, 403 143 77 1%-97.8 t0 98.3 A 577 l, 125 95 5l. 1%-Tetrahydrofurfury Alcohol Extract 577 886 53. 5 29 8%-Tetrahydrofurfuryl Alcohol Extract 577 S88 54 29 5%-Tetrahydroiurfuryl Alcohol Extract 57 7 721 25 13 Uniuhlbited Finished Panhandle Medium Motor Oil 485 583 20 11 l Volume percent extract-,from silica gel extraction of the phenol extract.

2 Percent Vis. Increase of Sample Percent Vis. Increase of Standard The oxidation test employed is used to compare the change in properties in oil after subjecting it to xed oxidation conditions. Usually it is desirable to compare the oil to be tested to a standard oil subjected to the same test. The test is carried out as follows:

Oxidation of an oil sample is carried out in a 200 cc. glass three-necked round bottom ask. The central neck of this flask is 5 cm. long and has an inside diameter of 3 cm. The two opposed side necks are 6 cm. long and 1.5 cm. inside diameter, and are situated at a 30 angle with the central neck, perpendicular to the surface of the spherical flask. The stirrer is a glass rod 0.5 cm. in diam'- eter, entering the flask through a glass tube bearing held in place by a rubber stopper in the central neck, with two glass blades 1.0 cm. long by 0.7 cm. wide welded to opposite sides of the bottom end of the glass rod at a 30 angle with .the vertical. The stirrer is driven by a `1'750 R. P. M. motor connected to the stirrer by a rubber tubing coupling. The blades of the stirrer are situated about 0.5 cm. from the bottom of the flask and spin in such a direction that their propeller-like action circulates the oil to the bottom of the ask, up along the sides of the iiask, back to the center of the flask, and down to the stirrer Ablades again. A considerable .amount of air issuckedfdown with the descending oil and intimately contacted with phenol extract.

it by the action 'of the stirrer. .A thermometer .Well cm. longer and 1.0 cm. inside diameter is situated in one side of the lnaskequiclistant from the tivo side arms. During the oxidation the nasi: is about two-thirds immersed in an oil bath maill- .tained at 375 F. The temperature of 'the oil in the `:flask is usually 5 to 10 F. below the temperature of the oil bath.

' 'The oxidation test is carried out in a specially constructed nask by 'stirring 100 cc. of the sample in the presence of air for sixteen hours at 375 F. At the end or" 'that time the flask is removed from the oil bath and tests obtained on the oxidized oil.

The data .presented in Table Il show that the vtetra-hydrourul'yl alcohol extract is effective in stabilizing an cxidizable Coastal lubricating oil. Furthermore, it will be seen that the oxidizable Coastal lubricating oils, to which the oxidation inhibitor has been added in an amount from 3 to 5 by volume, approach in quality, as measured by .the oxidation index, the quality of the original Panhandle medium motor oil from which the `phenol extract was obtained.

While one of the examples shows the dilution of the extract layer. with a, parainic solvent, it may be desirable to dilute the solvent extract, such as phenol extract, which is charged to the process with a parainic solvent to reduce the viscosity thereof and to facilitate the separation into phases on extraction with tetrahydrofurfuryl alcohol. Illustrative of paraiiinic hydrocarbons which may be used to dilute the solvent extract or the tetrahydrofurfuryl alcohol extract are :Dentaria hexane, heptane, octane, nonane and the like, including isomers thereof. Rather than use a Substantially pure parafnic hydrocarbon,

it may' be desirable to use a paramnic hydrocarfbon fraction boiling in the range from about 100 1i'.l up to about 300 F.

As another example of the practice of the present invention, a tetrahydrofurfuryl 'alcohol extract obtained in a single stage extract as described previously was rie-extracted with 200 volume per cent of tetrahydrofurfuryl alcohol with 1% by volume of water injection and an extract having a refractive index 11.52 of 1.5189 lwas ob- :alcohol to all acetone. Solvent mixtures containing from 20 to 9% by volume of acetone were Ihiglrlly ellicient in rejecting materials of lower refractive index into the rail'lnate, While the tetrahydrofurfulyl alcohol alone with Water injection as previously described was highly selective in concentrating highly refractive index matenais.

The invention has been described and claimed with respect to extracting a phenol extract of a lubricating oil fraction with a solvent comprising tetrahydrofurfuryl alcohol. While a phenol extract is preferred as the charge stock, other ,solvent extracts of 'lubricating oil fractions may be used. For example, furfural extracts of lubrieating oil fractions may be used in lieu of a Similarly, extracts of lubricatiner oil Vfractions produced by extracting lubrieating' oil fractions with solvents comprises liquid "sulfur dioxide, nltrobenzene, trichloroetliylena fil Chlorex, -chlorophenolg 'cresylic acid. pyridine and the like. As a general statement, it may be said that the solvent extract which forms a feed stock for the process of the present invention may be an extract of a lubricatingr oil produced by sole vent extracting same with a solvent which has a preferential selectivity for non-parafnic constituents. For example, the solvent will take into solution therein substantially non-parafllnic constituents and Will reject the substantially parat'- iinic constituents. It may be further said that the solvent extract of the lubricating oil fraction forming 'a feed stock 'of the present invention should be a Solvent extract obtained by extractin'g 'a lubricating oil fraction 'With a solvent other 'than that comprising tetrahyd-rofurfuryl alcohol.

The nature and objects of the present invention having been completely described and illustrated. what I Wish to claim as new and useful and to secure by Letters Patent is:

l. A method for producing an oxidation inhibitor suitable for use in lubricating oil which comprises the steps of admixing a solvent comprising tetrahydrofurfuryl alcohol 'with a phenol extract 'of a Panhandle medium motor distillate fraction 'in an amount and under conditions of temperature and pressure sufcient to cause formation of a second extract phase and a raffinate phase While maintaining a liquid state, separating said phases, removing said alcohol from said second extract phase, and recovering substantially alcohol-free hydrocarbons from said second extract phase suitable for 'use as an oxidation inhibitor.

2. A method for producing an oxidation inhibitor suitable for use in lubricating oil which comprises the steps oi admixing a solvent comprising tetrahydrofurfuryl alcohol with a phenol extract of 'a Panhandle medium motor distillate fraction an amount and under conditions of temperature and pressure suiiicient to cause formation cf a second extract phase'and a. raf"- ilnat'e 'phase While maintaining a liquid state, separating said phases, admixing the extract phase With a low viscosity paraninic solvent in an amount suilicient to reduce the viscosity thereof, adding to the admixture of the extract phase and 10W viscosity para-linie solvent a sufficient amount 'of water to reduce the solvency of the alcohol in said extract phase and to form a hydrocarbon layer and an aqueous alcohol layer, washing said hydrocarbon layer with `Water to remove alcohol therefrom, removing said low viscosity 'parafnic solvent from said hydrocarbon layer by' distilling same and recovering an oxidation inhibitor.

Y 3. A method for producing an oxidation inhibitor suitable for use in lubricating' oils which comprises the steps of countercurrently contacting in a solvent extraction Zone 'a phenolextract of a Panhandle medium motor distillate fraction with a solvent comprising tetraliydrofuifuiyl a1- cohcl in a ratio of alcohol to Solvent extract i'n the range between 1:1 and 4:1 at a temperature in the range between 29 and 100 C. and at a pressure suiiicient to maintain liquid phase conditions in said solvent extraction zone to form an extract phase and a rainate phase, adding sucient Water to said extract phase in said extraction zone to reduce the solvency of said alcohol therein, removing said water-containing extract phase from said solvent extraction lache,

one distillinc said water-containing extract pliage 9 to remove water and alcohol therefrom and to recover an oxidation inhibitor'.

4. A method for producing an oxidation inhibitor suitable for use in lubricating oils which comprises the steps of counter-currently contacting in a solvent extraction zone a phenol extract of a Panhandle medium motor distillate fraction with a solvent comprising tetrahydrofurfuryl alcohol and acetone, said alcohol and acetone being present in said solvent in a ratio no greater than 1:1, in a ratio of solvent to solvent extract in the range between 1:1 and 4:1 at a temperature in the range between 20" and 100 C. and at a pressure sufficient to maintain liquid phase conditions in said solvent extraction Zone to form an extractl phase and a raffinate phase, adding water to said extract phase in said extraction zone in an amount in excess of about 15% by Volume based on said extract phase, removing said Water-containing extract phase from said solvent extraction zone and distilling said Water-containing extract phase to remove Water and alcohol therefrom and to recover an oxidation inhibitor.

5. A method for producing an oxidation inhibitor suitable for use in lubricating oils which comprises the steps of counter-currently contactingr in a solvent extraction zone a phenol extract of a Panhandle medium motor distillate fraction with a solvent comprising approxi" mately two volumes of tetrahydrofurfuryl alcohol and one volume of acetone at a temperature of about 25 C. and at atmospheric pressure to form an extract phase and a raiiinate phase,

adding Water to said extract phase in said extraction zone in an amount in excess of about 15% by volume based on said extract phase, removing said Water-containing extract phase from said solvent extraction zone and distilling said water-containing extract phase to remove acetone and aqueous alcohol therefrom and to recover an oxidation inhibitor.

6. A process in accordance with claim 5 in which the phenol extract is admixed with a parainic hydrocarbon in an amount in the range from 10% to 150% based on said phenol extract prior to contacting with said solvent.

7. A process in accordance with claim 5 in which the rai'linate phase is admixed with acetone under conditions to form a secondary rafiinate and a secondary extract phase and in which said secondary extract phase is admixed with said phenol extract.

JAMES G. LILLARD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,883,374 Hill Oct. 18, 1932 2,054,052 Govers Sept. 8, 1936 2,106,234 Bray Jan. 25, 1938 2,114,524 Egli Apr, 19, 1938 2,220,016 Lyons Oct. 29, 1940 2,261,780 Whiteley Nov. 4, 1941 2,342,205 Manley Feb. 22, 1944 2,412,823 Mayland Dec. 17, 1946

Claims (1)

1. A METHOD FOR PRODUCING AN OXIDATION INHIBITOR SUITABLE FOR USE IN LUBRICATING OIL WHICH COMPRISES THE STEPS OF ADMIXING A SOLVENT COMPRISING TETRAHYDROFURFURYL ALCOHOL WITH A PHENOL EXTRACT OF A PANHANDLE MEDIUM MOTOR DISTILLATE FRACTION IN AN AMOUNT AND UNDER CONDITIONS OF TEMPERATURE AND PRESSURE SUFFICIENT TO CAUSE FORMATION OF A SECOND EXTRACT PHASE AND A RAFFINATE PHASE WHILE MAINTAINING A LIQUID STATE, SEPARATING SAID PHASE, REMOVING SAID ALCOHOL FROM SAID SECOND EXTRACT PHASE, AND RECOVERING SUBSTANTIALLY ALCOHOL-FREE HYDROCARBONS FROM SAID SECOND EXTRACT PHASE SUITABLE FOR USE AS AN OXIDATION INHIBITOR.

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