US2789145A - Method of removing thiophenols from phenols - Google Patents

Description

April 16, 1957 METHOD OF' REMOVING THIOPHENOLS FROM PHENOLS M. B. NEUWORTH Filed Aug. lO, 1954 2 Sheets-Sheet 1 46 noue-aus I6 Aaa/fous sal. VENT soLvE/vr 'un-u xr J r4s "-59 1 lo ,4 ze -aa u 'u 'll t k e z s E h g E 24 t 4l k z L-p u. n 2 g l2 h q E k 5 0 Q "I k g t a e 1 Je 0 1"-"1 az sz 2s naar/mums pendre l l "o 5| pHEnoLs lun/T114 INVENTOR. F/GURE MART/NBNEUWORTH April 16, 1957 M. B'NEUWORTH 2,789,145

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MAR' Tl/v NEI/WORTH m7 kuk A TTR/VEY United States Patent O METHOD 0F REMGVING THIOPHENOLS FROM PHENLS Martin B. Neuworth, Pittsburgh, Pa., assigner to Pittsburgh Consolidation Coal Company, Pittsburgh, Pa., a corporation of Pennsylvania Application August 10, 1954, Serial No. 448,947

9 Claims. (Cl. 269-627) This invention relates to the art of refining phenols, and more particularly, to the removal of thiophenols from phenols.

The two principal commercial sources of phenols are coke oven tar and petroleum distillates resulting from oil cracking processes. The conventional method of recovering phenols from either source is to extract them with aqueous caustic solution to produce Water soluble phenolate salts. The latter are separated from the source material by decantation and reconverted to phenols upon reaction with mineral acids. Other sources of phenols include tar from low temperature coal carbonization and oil shale distillates. The term phenols encompasses those hydroxy aromatic compounds, principally the mononuclear compounds, but also including the polynuclear compounds, for example, phenol itself, cresols, xylenols, higher methyl substituted phenols, ethyl phenols and higher alkylated phenols, bicyclic, polycyclic and dihydric phenols. The fraction of phenols boiling below 230 C. includes most of the commercially valuable phenols, i. e., phenol itself, cresols, xylenols and ethyl phenols.

Extraction of phenols by means of aqueous caustic solution is accompanied by the extraction of thiophenols since the latter are even stronger acids than the phenols themselves. The quantity of thiophenols in the Original source material varies widely, being sometimes as little as one percent by Weight of the phenols and ranging as high as 25 percent and above. Their presence in the eX- tracted phenols is undesirable for most industrial applications.

Many schemes have been proposed for the removal of the thiophenols from the caustic extracted phenols. The successful ones are based upon the ease of oxidation of the thiophenols to disuldes. lt is diicult to keep thiophenols free of disuides since normal handling will expose them to air and result in at least partial oxidation. Accordingly the proposed schemes, in View of this behavior, have resorted to deliberate oxidation by air blowing to completely convert the thiophenols to disuldes. The latter are readily separable from the phenols because of their insolubility in an aqueous medium.

The general method of oxidizing thiophenols to disuldes has three disadvantages; Firstly, destruction of a signicant quantity of the valuable phenols results from the oxidation; secondly, redistillation of the phenols causes a reversion of any remaining disulli'des to thiophenols; 4there thirdly, the thiophenol content of the resulting phenols is still not reduced suiciently for some commercial applications.

Analysis of a typical commercial product of petroleum cresylics (i. e. phenols boiling below 230 C.) that were recovered by caustic extraction and oxidized to remove thiophenols shows 97.7% by weight of phenols; 1% by weight of neutral oil; 1% by weight of sulfur compounds (total); and 0.3% by weight of tar bases. The sulfur is, of course, present in organic sulfur compounds, principally unoxidized or reconverted thiophenols, and disuldes resulting from oxidation of the thiophenols.

2,789,145 Patented Apr. 1.6, 1957 2 For many industrial resin applications, 1% by weight of sulfur compounds is too high.

ln accordance with the present invention, I have provided a method for removing thiophenols from phenols which are substantially free of. neutral oil. The method comprises contacting the contaminated phenols in a continuous, countercurre'nt' extraction zone with a low boiling parainic naphtha fraction as one vsolvent and an aqueous solution of an oxygenated hydrocarbon as the other solvent. The oxygenated hydrocarbons used in the present invention are glycols, polyglycols and their methyl and ethyl ethers.

When one contacts a mixture of phenols and thiophenols with a polar and a nonpolar solvent, one would expect the more strongly acidic thiophenol to remain lin the polar solvent (aqueous solutions of oxygenated hydrocarbons) However, I have found that the reverse is true. The less acidic phenols remain in the polar solvent (aqueous oxygenated hydrocarbons) and the. more acidic thiophenols are recovered in the nonpolar solventy (low boiling parainic naphtha). The separation resulting from the present extraction treatment is extremely effective; phenols of high purity can be recovered in virtually quantitative yields.

In the process of my invention, the feedstock consists of phenols from which substantially all the neutral oil has been separated. The etliciency of separating sulfur' compounds from phenols decreases as the; neutral oil content ot' the mixture increases. ln general, the neutral oil contamination of the feed material should be'lessthan about l0 percent, preferably less than about 5 percent. This feed stock generally but not necessarily has a boiling range from 160-300D C., or some portion thereof, particularly the fraction boiling upto 230 C. The organic sulfur contaminants comprising principally thiophenols (i. e. thiophenol itself, thiocresols, thioxylenols, etc.) may be present in amounts from about 0.5 to 25% by weight of the feedstock. The present process iseiective in removing thiophenols from phenols and also eective in eliminatingV the more readily separated' sulfur compounds, such as disuldes. Thus the present process can be applied to fresh phenolsas well as those which have been subjected to airblowing for partial oxidation of the thiophenols.

The contaminated feed stock is fed into a continuous, countercurrent, double'solvlent, extraction zone. Aqueous oxygenated hydrocarbon solution is fed into one end of the zone, anda low boiling, essentiallyparatinic naphtha fraction is fed into the other end" of the' Zone. The aqueous solvent passes through the extraction zone dissolving substantially all the phenols. The naphtha passes countercurrently through the Zone dissolving the thiophenols and any residual neutral oil. The phenolsv then may be recovered readily from the aqueous solvent by distillation, provided the boiling: ranges of the phenols and solvent are dilerent. Similarly, the thiophenols may be recovered from the naphtha solution for disposal as waste or for commercial use depending upon thev quantity.

The oxygenated hydrocarbon materials which I` have found to be effective in the present invention are glycols, polyglycols, and their methyl and ethyl ethers. These compounds may be represented by the following formula:

MOCEZIRONH Where R is H, CHs'or C21-I5; R' is H or CH3; and n is an integer from l to 10 inclusive. It is necessary that these oxygenated'hydrocarbon materials be used in an aqueous solution containing from about 50/ to 80% by Weight of the oxygenated hydrocarbons. In concentrations lbelow about 50 percent by weight of oxygenate'd hydrocarbons, recovery of phenols is too low to be practical. Above about 8O percent concentration of oxygenated hydrocarbons, the aqueous solvent dissolves the thiophenols so that the extracted phenols remain contaminated to an undesirable extent.

Suitable .materials for the aqueous solvent include 4ethylene glycol, propylene glycol, monomethyl and monoethyl ethers of ethylene glycol, diethylene glycol, dipropylene glycol, monomethyl and monoethyl ether-s of diethyl- The processY of this invention is further critically conditioned by the characteristics of the naphtha solvent. lt "must lbe essentially paraflinic in character. may 'be obtained from the distillation of parainic petro- Such solvents leum stock. VIts boiling range should Ibe 60l30 C. but

preferably 60l00 C. in order -to facilitate the subse- Q quent stripping of the naphtha solvent from the naphtha y extract. And finally, the naphtha density should be less th-an 0.80 and preferably less than 0.75 to insure a grav- 'ity difference between the two phases in the extraction column suiiicient to Veffect a ready separation of the phases. The hexane cut of parainic naphtha combines all these critical properties and accordingly is preferred as the nonpolar solvent.

For a clear understanding of my invention, its objects and advantages, reference should Ibe had to the following description and accompanying drawings in which:

Figure l is a diagrammatic illustration of apparatus adapted for the practice of the preferred embodiment of this invention; and

Figure 2 is a diagrammatic illustration of an alternate embodiment of this invention.

Referring to Figure l, a feedstock comprising phenols contaminated with sulfur compounds as previously devfined, is pumped continuously from a storage tank 10 through a pipeline 12 into a continuous countercurrent,

ldouble solvent extractionV zone consisting, in the preferred embodiment, of `a multistage, vertical, center feed extraction column 14. The extraction column may be of any convenient design capable of providing a sucient number of theoretical extraction stages to effect the desired separation of phenols. A conventional packed tower may be used, as well as a pierced plate column, a ybubble plate column, or a column containing alternate zones of quiescence and turbulence.

A polar aqueous solvent, as previously defined, is fed continuously from an aqueous solvent storage tank i6 through pipeline 18 into the top of the extraction column 14. Naphtha is fed continuously from the naphtha storage tank 20 through a pipeline 22 into the base of the extraction column 14. Since the density of the aqueous solvent exceeds the density of the naphtha, the aqueous solvent descends through the column, dissolving phenols While the lighter naphtha passed countercurrently upward through the column, dissolving the thiophenols contained in the feed. Column throughput and contact time lare dependent upon column design.

For every volume of feedstock, from 0.5 to 5.0 volumes of vaqueous solvent and from 0.5 to 5.0 volumes of naphtha should be employed, where lboth high phenol recov- 1 ery and high phenol purity are desired. These flow ratios yare therefore preferred. While either of the two solvents may be employed as the continuous phase in the extrac- Vindependent of the temperature at which the column is operated, it is preferred to operate `the extraction column within the range of 60-120" F. The increased viscosity of the phenol feedstocks below this range introduces column operation difficulties, while the increasing solubility of the thiophenols in the aqueous solvent at higher temperatures decreases the purity of the recovered phenols. It' necessary, the extraction column may be heated `or cooled in any convenient manner. Y

The aqueous solvent, containing purified phenols, is withdrawn continuously from the lbottom of the extraction column 14 through `a pipeline 24 and fed into a stripping column 26 for the separation of the aqueous solvent from the recovered puried phenols. Where the aqueous solvent contains oxygenated hydrocarbons having a boiling range below that -of the recovered phenols, the oxygenated hydrocarbons will pass overhead through a conduit 38, a condenser 40 and a conduit 42 to the aqueous solvent tank 16 for recirculation in lthe process. A portion of the condensed distillate may Ibe returned to the column 26 as reux through -conduit 44. The water entering the stripping column 26 also will pass overhead with the oxygenated hydrocarbon solvent. Puritied phenols are recovered vat the bottom of the `stripping column 26 through a conduit 28 and a condenser 32. Any water remaining with the purified phenols is separated in a decanter 30 and returned for recirculation as solvent through conduit 36. Purified phenols essentially free of thiophenols are recovered from the decanter 30 through conduit 34. Fresh oxygenated hydrocarbon solvent may lbe added as makeup through conduit 46.

Naphtha with dissolved thiophenols and any residual neutral oil leaves the top of the extraction column 14 through pipeline 48 and passes to a stripping column 50 where the naphtha is separated from the thiophenols. Naphtha passes overhead from the stripper 50 through a pipeline 52 and redux condenser 54. A portion of the condensed naphtha may be recirculated rthrough pipeline 56 as reflux for the stripper 50. The remainder of the naphtha is returned to the naphtha storage tank 20 through pipeline 58 for recirculation. Thiophenols leave the column 50 as a `bott-om product through pipeline 60. A cooler 62 may be inserted in the exit pipeline 60 to cool the sulfur containing product.

Where the oxygenated hydrocarbon solvent of this invention has a boiling range higher than that of the phenols being treated, the process should be conducted in accordance with Figure 2. Referring to Figure 2, a feedstock containing phenols and sulfur compounds is introduced from a storage tank 70 through a conduit 72 into a countercurrent extraction column 74. An aqueous solution of an oxygenated hydrocarbon material is introduced .into the top of the column 74 lfrom a solvent tank 76 through a conduit 78. A low boiling parat-linie naphtha Vsolvent from storage tank S0 is introduced through couduit 82 into the bottom of the extraction column 74. The aqueous solvent passes downwardly through the column dissolving the phenols contained in the feed material. The paraiiinic naphtha solvent passes upwardly through the column dissolving thiophenols and any residual neutral oils which may exist in the feed. The naphtha extract is recovered from the top of the column 74 through conduit 88 and sent to a naphtha stripping column 90. ln the naphtha stripper 90 the low boiling solvent i-s vapor- 'ized and recovered through conduit 92, condensed in a reflux condenser 94 and returned through conduit 98 to the naphtha storage vessel 30. A portion of `the con- -densed naphtha may be returned to the stripper 99 through the conduit-96 as reflux. Thiophenols are recovered from the stripping column 90 through a conduit 100. If desired a cooling condenser 102 may be provided in the withdrawal conduit.

The high boiling aqueous solvent extract is recovered from the bottom of the extraction column 74 through a conduit 84 and sent to a phenol stripping column` 86. Phenols and water pass from the top of the stripper 86 'through a condi1it1104 to areiux condenser 106. Condensed Water andl phenols are sent to a decanter 108 through a conduit 110. A portion of the condensed water and ph'enolsrnay'be returned to the top of the stripping column 86 through a conduit 112 as redux. Purified phenols are recovered from the decanter 108 through a 6 They included.(l) ethylene glycol-monomethyl ether; (2) ethyleneY glycol monoethylether; (3) ethylene glycol; (14) triethylene glycol; (5) polyprcpyleneglycol 150; and (-6) polyethylene glycol'600. The concentration of the aqueous solvent was from 70 to 80% by weight of the oxygenated hydrocarbon material.

The conditions and results 0f these runs are reported in the following Table I.

Table I.-Remooal of thophenols a/nd dtsulfldes from phenols usi/ng as solvents hewane and aqueous solutions of oygenated hydro,cttrfbcmsV Ethylene G1. co1 Ethylene Triethyl- Dipropyl# Polyethyl- Mgn Glycol Ethylene ene Glycol ene ene Glycol Aqueous SolventComponeut meth 1 Mono- Glycol Glycol 1' 600 2 Ethel', ethyl Ether Boiling Temperature, D C 124. 5 195 197 287 232V 40l) R CH3 (13H5 H H H H R'- H H H H CHI CHI 15.-.- 1 1 1 2 8-10 Aqueous Solvent Conc. (Wt. perce1! 70 80 75 70 70 70 Feed Rates (Volumes): v

1 1 1 1 1 1 2 3 2 2 2 2 3 4 3 3 3 3 Recovery of Phenols iu Extract Y (W't. percent) 98. 0 95. 3 93. 8 99. 5 95. S 95. 4 Contaminants in Recovered Phenols (Wt. percent):

Thiopheuols 0. 07 0. 07 O. 007 0. 14 0. 04 0. 2 Disulfides 0. 13 0.06 0.023 0. 10 l). 08 0. 03

1 The dipropylenc glycol in this run -w'as a commercially available solvent sold under the name Polypropylena 150, consisting of a narrow boiling fraction o propylene glycol having an average molecular weight o about 150. It is marketed by the Carbon and Carbide Chemicals Corporation.

Polyethylene glycol 600 is a commercially available solvent consisting of a narrow boiling distillate of polyethylene glycol having an average molecular weight of about 600. It is marketed under the trade name "Carbowar by the Carbon and Carbide Chemicals Corporation.

withdrawal conduit 114. The water inthe decanter S is separated from the phenols and returned for recirculation to the aqueous solvent storage vessel 76 through a conduit 116.

The high boiling oxygenated hydrocarbon material used in the aqueous solvent iswithdrawn from the bottom of the stripping column 36 through a conduit 11S and a cooling condenser 120. High boiling oxygenated hydrocarbon material is returned to the aqueous solvent storage vessel 76 for recirculation in the system. Additional high boiling oxygenated-hydrocarbon material may be introduced to the system as makeup through a conduit 120.

Asrriention'ed previously, the system shown in Figure 2 is employed when the oxygenated hydrocarbon material has a higher. boiling range than the phenols being separated. The advantage o'f the use of a high boiling oxygenated hydrocarbon material is that the large quantities of solvent required need not be vaporized prior to reuse in the process. In the practice of the present invention according to Figure 2 only the product' purified phenols and water from the aqueous solvent need be vaporized to effect recovery of the phenols.

By yva'y of example, a series of runs will now be described 'which vwere conducted on a `commercially available product consisting of petroleum cresylics, i. e., phenols, having a boiling range of 375 to 450 F. The petroleum cresylics employed as the feed material contained the following contaminants; thiophenol 0.6%, disuldes 4.0%, and neutral oil 1.0%. The elemental sulfur in the feed material was 1.4% by weight.

The runs were conducted in a 1-inch diameter, 8-feet long, center feed, countercurrent extraction column containing in its contact zone 29 settling stages alternately disposed with 28 agitation stages. The column was operated at a temperature of C. The continuous solvent. phase was commercial grade hexane which was employed asv the nonpolar solvent.

Six different oxygenated hydrocarbons having the following formula:

moorden/OH where R is H, CH3 or CzHsg. R is H or CH3; and n is an integer from l to v10 inclusive, were employed as the primary component of the vaqueous polar solvent.

In the runs recorded in Table I recovery of phenols ranged from 93.8-99.5%. The thiophenol contamination was reduced from its initial value of 0.6 weight percent to a value ranging from 0.007-0.l4 weight percent. The disulfide content was reduced from its initial value of 4.0% to a value in the range of 0.0234113 weight percent. Accordingly, even if the phenols containing thiophenOls are subjected toa preliminary air blowing treatment, the resulting disulfides can be substantially eliminated by the present process.

To facilitate separation of the recovered phenols from the solvents, it is preferred that the oxygenated hydrocarbon used in the polar solvent have aboiling range outside that of the phenols in the feedstock. Thus preferred solvents of the examples in Table I would include ethylene glycol monorne'thyl ether as boiling below the range of the cresylics, and triethylene glycol, polypropylene glycol and polyethylene glycol 6002s boiling above the range of the cresylics. The use of the other two examples, ethylene glycol monoethyl ether and ethylene glycol is Wellsuited for eectng the desired elimination ofthe sulfur compounds from the phenols, but it results in an extract which is not readily separable from the puried phenols by distillation.

And now according to the provisions of the patent statutes, I have explained the principle, preferred construction, and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

1 claim:

1. A method of separating thiophenols from a mixture of phenols and thiophenols that is substantially free of neutral oils which comprises the steps of feedingl said mixture of phenols to an extractionV zone, feeding to one end of said extraction zone an aqueous solution containing from about 50 to about 80 percent by weight of an oxygenated hydrocarbon having the formula where -R is a radical selected from the class consisting-of H, 'CH3 and CzHs; R' is a radical selected from the class consisting of H and CH3; and n is an integer having a value in the range of 1 to 10, feeding a parainic naphtha fraction boiling in the range of 60 to 130 C. and having a density of less than 0.8 to the other end of said extraction zone, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction. v v Y 2. A method Vof separating thiophenols from a mixture of phenols Vand thiophenols that is substantially free of neutral oils which comprises the steps of feeding said mixture of phenols to a vertical extraction zone at a point located between the ends thereof, feeding to the upper end of said vertical extraction zone-an aqueous solution containing from about 50 to about 80 percent by Weight of an oxygenated hydrocarbon having the formula where R is a radical selected from the class consisting of H, CH3 and CzHs; R is a radical selected from the `class consisting of H and CH3; and n is an integer having a value in the range of l tol 10, feeding a paraiinic naphtha fraction boiling in the range of 60 to 130 C. and having a density of less than 0.8 to the bottom of said extraction zone, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

3. A method of separating thiophenols from a phenol distillate fraction boiling within the range 170 to 230 C. comprising phenols and thiophenols and being substantially free of neutral oils, comprising the steps of feeding said distillate fraction to a vertical extraction zone at a point located between the ends thereof, feeding to the upper end of said vertical extraction zone an aqueous solution containing from about 50 to about 80 percent by weight of an oxygenated hydrocarbon boiling below 170 C. and having the formula where R is a radical selected from the class consisting of H, CH3 and CzHs; R' is a radical selected from the class consisting of H and CH3; and n is an integer having a value in the range of l to 10, feeding to the bottom of said extraction zone a paraflnic naphtha fraction boiling in the range of 60 to 130 C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

4. A method of separating thiophenols from a phenol distillate boiling within the range of 170 to 230 C. Comprising phenols and thiophenols and being substantially free of neutral oils, comprising the steps of feeding said distillate fraction to a vertical extraction zone at a point located between the ends thereof, feeding to the upper end of said vertical extraction zone an aqueous solution containing from about 50 to about 80 percent by weight of an oxygenated hydrocarbon boiling above 230 C. and having the formula where VR is a radical selected from the class consisting of H, CH3 and CzHs; R is a radical selected from the class consisting of H and CH3; and n is an integer having a value in the range of l to 10, feeding to the bottom of said extraction zone a parainic naphtha fraction boiling in the range of 60 to 130 C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in counter- Y current relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction. Y

5. A method of separating thiophenols Vfrom a mixture of phenols and thiophenols that is substantially free of neutral oils which comprises the steps of feeding said mixture of phenols to an extraction zone, feeding to one end of said extraction zone an aqueous solution containing from about 50 to about 80 percent by Weight of ethylene glycol monomethyl ether, feeding to the other end of said extraction zone a parainic naphtha fraction boiling in the range of 60 to 130 C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols princpally in the aqueous solution and the thiophenols principally in the naphtha fraction.

6. A method of separating thiophenols from a mixture of phenols and thiophenols that is substantially free of neutral oils which comprises the steps of feeding said mixture of phenols to an extraction zone, feeding to one end of said extraction zone an aqueous solution containing from about 50 to about 80 percent by weight of ethylene glycol monoethyl ether, feeding to the other end of said extraction zone a paranic naphtha fraction boiling in the range of 60 to 130 and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

7. A method of separating thiophenols from a mixture of phenols and thiophenols that is substantially free of neutral oils which comprises the steps of feeding said mixture of phenols to an extraction zone, feeding to one end of said extraction Zone an aqueous solution containing from about 50 to about 80 percent by weight of triethylene glycol, feeding to the other end of said extraction zone a parainic naphtha boiling in the range of 60 to 130 C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrentvrelation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

8. A method of separating thiophenols from a mixture of phenols and thiophenols that is substantially freeV of neutral oils which comprises the steps of feeding Vsaid mixture of phenols lto an extraction zone, feeding to one end of said extraction zone an aqueous solution containing from about 50 to about 80 percent by Weight of dipropylene glycol, feeding to the other end of said extraction zone a paraiinic naphtha boiling in the range of to C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

9. A method of separating thiophenols from a mixture of phenols and thiophenols that is substantially free of neutral oils which comprises the steps of feeding said mixture of phenols to an extraction zone, feeding to one end of said extraction zone an aqueous solution containing from about 50 to about 80 percent by weight of polyethylene glycol, feeding to the other end of said extraction zone a paraffinic naphtha boiling in the range of 60 to 130 C. and having a density of less than 0.8, passing said aqueous solution and said naphtha fraction through said extraction zone in countercurrent relation, and recovering the phenols principally in the aqueous solution and the thiophenols principally in the naphtha fraction.

References Cited in the ile of this patent UNITED STATES PATENTS 2,218,139 Thomas et al. Oct. 15, 1940 2,556,213 Pieroni et a1. June 12, 1 2,666,796 Gerin et al. Jan. 19, 1954

Claims (1)

1. A METHOD OF SEPARATING THIOPHENOLS FROM A MIXTURE OF PHENOLS AND THIOPHENOLS THAT IS SUBSTANTIALLY FREE OF NEUTRAL OILS WHICH COMPRISES THE STEPS OF FEEDING SAID MIXTURE OF PHENOLS TO AN EXTRACTION ZONE, FEEDING TO ONE END OF SAID EXTRACTION ZONE AN AQUEOUS SOLUTION CONTAINING FROM ABOUT 50 TO ABOUT 80 PERCENT BY WEIGHT OF AN OXYGENATION HYDROCARBON HAVING THE FORMULA

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