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Publication numberUS2910518 A
Publication typeGrant
Publication dateOct 27, 1959
Filing dateJun 25, 1957
Priority dateJun 25, 1957
Publication numberUS 2910518 A, US 2910518A, US-A-2910518, US2910518 A, US2910518A
InventorsBernard B Lampert, Jr James V Murray, David W Peck
Original AssigneeUnion Carbide Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Separation of aromatic hydrocarbons from aliphatic hydrocarbons using ketodioxane
US 2910518 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Oct. 27, 1959 B. B. LAMPERT ETAL 2,910,518

SEPARATION OF AROMATIC HYDROCARBQNS FROM ALIPHATIC HYDROCARBONS USING KETODIOXANE Filed June 25, 195": 3 Sheets-Sheet 3 Me'fhylnaph'lhalenes A?! AVA )XIAA ll 02 -0 Y AvAv 6 Am Kefodioxane BERNARD B LAMP Decalin JA sv. RRAY,

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United States Patent SEPARATION OF AROMATIC HYDROCARBONS FROM ALIPHATIC HYDROCARBONS USING KETODIOXANE Bernard B. Lampert, Pittsburgh, Pa., and James V. Murray, Jr., and David W. Peck, South Charleston, W. Va., assignors to Union Carbide Corporation, a corporation of New York Application June 25, 1957, Serial No. 667,878

5 Claims. (Cl. 260-674) This invention relates to chemical processes. More particularly, it relates to the separation of aromatic hydrocarbons from admixture with aliphatic hydrocarbons using ketodioxane.

In the common raw material sources of hydrocarbons for the chemical industry there are usually found intimate mixtures of aromatic and aliphatic hydrocarbons. This is true whether the hydrocarbons are derived from petroleum sources such as oil or shale, or from carbonaceous materials such as coal tar fractions or coal hydrogenation product fractions. Such mixtures, regardless of source, must ordinarily be separated into generally aromatic and non-aromatic fractions as a prerequisite to their commercial utilization. Our invention has been developed using coal hydrogenation fractions (as well as artificial binary mixtures) and is described and illustrated below with such coal hydrogenation products. However, it is in no sense limited to these materials but is generally applicable to any mixture of aromatic and aliphatic hydrocarbons regardless of source.

Due to the prevalence of such mixtures and the demand for their separated components, numerous methods have been suggested for the separation of aromatic compounds from aliphatic compounds. Prominent among the methods suggested have been those involving extraction with a selective solvent, usually extraction of the aromatic compounds by the solvent. Solvents suggested for this purpose have included such compounds as liquid sulfur dioxide, which requires special lowtemperature equipment, and ethylene carbonate, which is difficult to recover without decomposition, as well as others such as ethylene glycol which is somewhat limited in the range of compounds it can separate. i

We have now discovered that ketodioxane is useful as a selective solvent for separating aromatic hydrocarbons from aliphatic hydrocarbons. It is particularly desirable as a solvent when applied to a broad and complex aromatic-aliphatic mixture such as coal hydrogenation neutral light oil, a gross aromatic-nonaromatic oil fraction having a boiling temperature range of 100 C. to 260 C. and from which most of the acidic and basic constituents have been removed. Ketodioxane can also be called (2- hydroxyethoxy) acetic acid laotone and can be represented by the formula: r

Hg CH:

(It is potentially an inexpensive, easily available solvent, being readily produced in good yield by the catalytic dehydrogenation of diethylene glycol.

I In the drawings:

Figure 1 is a schematic representation of an embodiment of the invention wherein the aromatic hydrocarbons are separated from the ketodioxane extract by distillation.

Figure 2 is a schematic representation of an embodi- 2,910,518 Patented Oct. 27, 1959 ment of the invention wherein the aromatic hydrocarbons are separated from the ketodioxane extract by back extraction with an aliphatic naptha.

Figure 3 is a schematic representation of an embodiment of the invention wherein the aromatic hydrocarbons are separated from the ketodioxane extract by hydrolyzing the ketodioxane and removing it in water.

Figure 4 is a ternary diagram of the relative solubilities of benzene, normal heptane and ketodioxane.

Figure 5 is a ternary diagram of the relative solubilities of methyl-naphthalenes (50% alphaand 50% beta-), decalin and ketodioxane.

Figure 6 is a ternary diagram of the relative solubilities of tetralin, decalin and ketodioxane.

In the practice of the invention, the aromatic-aliphatics mixture, whether a simple binary mixture of two compounds or a complex mixture such as coal hydrogenation neutral light oil, is contacted with ketodioxane which preferentially dissolves or extracts the aromatic hydrocarbons. The ketodioxane extract of aromatics is removed from the aliphatics and the aromatics are recovered from the extract. The extraction of the aromatics with ketodioxane must be conducted at a temperature above 28 C., which is the freezing point of ketodioxane. Temperatures between 30 C. and 60 C. will be found suitable for most applications, although higher temperatures may be employed if desired. However, the temperature of the extraction should not approach the boiling point of the lowest boiling component of the mixture being extracted. Atmospheric pressure is suitable for the extraction and is preferred. If desired, however, subatmospheric or superatmospheric pressure could be employed. In varying the temperature and/ or the pressure, the most important consideration is that these conditions should be such that the aromaticraliphatics: feed mixture, the ketodioxane solvent, the extract and the ratfinate will all remain the the liquid state during the actual extraction.

For the most effective separation of the aromatic hydrocarbons from the aliphatics, a multistage extraction apparatus is preferred. The relative quantity of ketodioxane employed as solvent is not extremely critical and may vary from as little as one part by weight of ketodioxane for 20 parts by weight of aromatic-aliphatic mixture to as much as 20 parts by weight or more of ketodioxane for one part by weight of mixture. The relative quantity used will of course be influenced by the proportion of aliphatics in the mixture. We have found that for neutral light oil mixtures from coal hydrogenation between 2 and 3 parts by weight of ketodioxane to one part by weight of neutral light oil is preferred.

When the extraction has been accomplished the aliphatic hydrocarbons are left as product and the aromatic hydrocarbons are in the ketodioxane extract and must be recovered therefrom. The boiiing point of ketodioxane is 216 C. If the aromatics which have been extracted by the ketodioxane all boil at temperatures appreciably below 216 C. they may be readily separated from the ketodioxane by distillation according to the embodiment of the invention illustrated in Figure 1 of the drawing. Such distillation is normally at atmospheric pressure although subatmospheric or superatmospheric pressures could be used if desired. This embodiment is most useful in separating simple mixtures of aromatics and aliphatics when there is only one or a few aromatic hydrocarbons all boiling below 216 C. When any of the aromatics being separated have boiling points close to that of ketodioxane, distillation is not available for the separation and other means must be employed.

One such means involves back extraction with a naphtha and is illustrated in Figure 2 of the drawing. In this embodiment of the invention the ketodioxane extract of aromatic hydrocarbons is itself extracted, that is, back extracted, with an aliphatic naphtha. The aliphatic naphtha, being miscible with aromatic hydrocarbons but immiscible with the ketodioxane, extracts the aromatic hydrocarbons and leaves the ketodioxane for reuse. The aliphatic naphtha is chosen to have a boiling point temperature substantially different from the boiling pointtemperatures of any of the aromatic hydrocarbons so that it may be readily separated from them by distillation. Aliphatic naphthas useful in the invention include pentane, hexane, heptane and octane, and any of their isomers, as well as cyclopentane, methylcyclopentane, dimethylcyclopentane, ethylcyclopentane, cyclohexane, and methylcyclohexane, as well as petroleum ether fractionshaving boiling temperatures below 120 C.

Like the principal ketodioxane extraction thenaphtha back extraction must be conducted at a temperature above 28 C. and below the boiling point temperature of any of the compounds. emperatures between 30 C. and 60" C. havebeen found generally suitable. Atmospheric pressure is suitable for the back extraction and is preferred. If desired, however, subatmosphericor superatmospheric pressure could be employed. In varying the temperature and/ or the pressure, the most important consideration is that these conditions should be such that the ketodioxane-aromatics feed solution, the aliphatic naphtha solvent, the extract and the raffinate will all remain in the liquid state during the back extraction.

'For tl e most ehfective back extraction of the aromatics from the ketodioxane a multistage extraction ap paratus is preferred. The relative quantity of aliphatic naphtha employed as back extractant is not extremely critical and may vary from as little as'one part by weight of naphtha for 20 parts by weight of ketodioxane-aromatics solution to as much as 20 parts by weight or'more of naphtha for one part by weight of ketodioxane-aromatics solution. The relative quantity used will of course be influenced by the proportion of aromatics to ketodioxane in the solution. We have found in work with neutral light oil mixtures from coal hydrogenation that between 0.5 and 4 parts by weight of aliphatic naphtha per one part by weight of ketodioxane-aromatics.solution is preferred. When the back extraction has been accomplished the naphtha can be distilled from the naphthaaromatics solution and the aromatics distillant can then be Water washed, if desired, to remove residual ketodioxane.

Another method of separating the aromatics from the ketodioxane extract thereof, which can be employed when any of the aromatics being separated have boiling points close to that of ketodioxane, is illustrated in Figure 3 of the drawing. In this embodiment of the invention water is added to the ketodioxane extract of aromatics. Addition of the water causes the ketodioxane to hydrolyze to (Z-hydroxyethoxy) acetic acid which dissolves in the water. The mixtures separates into an aromatics layer and a water layer with the (Z-hydroxyethoxy) acetic acid dissolved in the water layer. The layers are then removed separately. The addition of the water, hydrolysis and separation of the layers are normally conducted at room temperatures and atmospheric pressure, although elevated temperature and subatmospheric or superatmospheric pressure could be employed provided all components remained in the liquid state. After separation of the layers, the water solution of (.2-hydroxyethoxy) acetic acid is distilled at atmospheric pressure and after the water, including the water of hydrolysis, is removed: as distillate, the ketodioxane is recovered as. distillate for reuse. The aromatic layer can be washed with water if desired, to remove any traces of ketodioxane.

The embodiments of the invention can be described in detail with reference to the drawings.

In Figure 1 of the drawing is illustrated the embodiment of the invention wherein a hydrocarbon mixture is extracted with ketodioxane in the extractor 11 and the ketodioxane is recovered from the extract in still 16. This embodiment is used when the aromatic hydrocarbon being separated will not co-distill with ketodioxane.

The hydrocarbon mixture is introduced into the extractor 11 through line 12. Concurrently ketodioxane is introduced into the extractor 11 through line 13. As the extraction proceeds the ketodioxane extract of arcmatic hydrocarbon is removed from the extractor 11 through line 14. The rafiinate from the extraction is the nonaromatic hydrocarbons which are removed from the extractor 11 through line 15 as product. The ketodioxane-aromatics extract removed through. line 14 is conducted therein into a still 16. As distillation proceeds the ketodioxane and the aromatic hydrocarbons are removed as distillate, the lower boiling of the two being distilled off first. The aromatics are removed as product through line 17. The ketodioxane is removed through line 18 and recycled therein to the ketodioxane feed line 13, for reuse in the extractor 11.

Figure 2; of the drawing illustrates a second embodiment of the invention wherein the hydrocarbon mixture is extracted with ketodioxane in extractor 21' after which the ketodioxane-aromatics extract is back-extracted with an aliphatic naphtha in a second extractor 22', from which the ketodioxane is recycled for reuse. The naphtha-aromatics extract is distilled in still 23 to remove the naphtha for recycle. The aromatic hydrocarbons are then water washed in a third extractor. 2.41 and removed therefrom as product. This embodiment may be employed where the aromatichydrocarbons and ketodioxane have boiling points close together or azeotrope, so as to co-distill.

The hydrocarbon mixture is introduced intothe first extractor 21 through line 25. Concurrently ketodioxane.

is introduced into the extractor 21 through line 26., Asthe extraction proceeds the ketodioxane extract of 'aro,. matic hydrocarbons is removed from extractor 21 through line 27. The raffinate from the extraction is the non aromatic hydrocarbons which are removed from; the extractor 21 through line 28 as product. The ketodioxanearomatics extract removed through line 27 is conducted therein into a second extractor 22 wherein it is backextracted. with an aliphatic naphtha which is introduced into the, extractor 22 through line 29. As the backextraction proceeds the naphtha extract of aromatics is removed from the extractor 22 through line 30. The; ketodioxane residue from the back-extraction is removed from the extractor 22 through line 31 and recycled therein to the ketodioxane feed line 26 for reuse in the process.

The naphtha extract of aromatics removed through line 30 is conducted therein into the still 23. As the; distillation proceeds in still 23 the naphtha distillate; is

removed from the still 23 through line 32 and recycled therein to the naphtha feed line 29 for reuse in the process. the still 23 through line 33 and conducted therein into extractor 24. through line 34: In extractor 24 the water washes, any

residual traces of ketodioxane out of the aromatics and ketodioxane occurs in a water layer which separates-.

from the aromatics. The aromatics are then conducted: to an extractor 43 where they are washed with water and then recovered therefrom as product. The water solutionof (Z-hydroxyethoxy) acetic acid, the hydrolysis productof ketodioxane, isconducted to a still 44 where The distillate of aromatics is removed from Water is introduced into extractor 2,4.-

extractor '43.

arrears the Water is first removed' as distillate and "the ketodioxane is then recovered as distillate .for recycleand reuse.

The hydrocarbon mixture is introduced into the "first extractor 41 through line 45. Concurrently ketodioxane -issintroduced into the extractor 41 through line 46. As the extraction proceeds the ketodioxane extract of aroma'tic hydrocarbons is'renioved from extractor 41 through line 47. The :rafiinatefrom .the extraction is the nonaromatic hydrocarbons which are removed from the ex -tractor 41 through line 48aslproduct. The ketodioxanearomatics extract removedthrough line 47 is conducted therein into a mixing-settling tank 42. Water is introduced into the tank 42 through line 49 and as it mixes with 'the ketodioxane-aromatics extract the ketodioxane is =converted by hydrolysis to (2-hydroxyethoxy) acetic acid and dissolved in the water. Upon standing the aro matic-hydrocarbons rise to the surface and separate from the water solution so that two layers are formed. The water'solutionof (Z-hydroxyethoxy) acetic acid is with- "drawn :from the tank42 through line 50.

The aromatic hydrocarbons are removed from the tank 42 through line 51 wherein they are conducted into an Water is introduced into extractor 43 throughline-SZ. In extractor 43 the water washes any "residual :traces of ketodioxane out of the aromatics and the washed aromatichydrocarbons are removed from the extractor-43 as :product through line 53. The wash water with traces'of ketodioxane is removed from the extractor -43 through li-ne54. The water solution of (2-hydroxyethoxy) acetic acid -in line 50 is conducted therein into a still 44. :As distillation proceeds in still 44 the (2- hydroxyethoxy) acetic acid is converted back to ketodioxane as the water, including the water of hydrolysis, is removed from the still 44 first as distillate through line 55. The ketodioxane is then'removed from the still 44 as distillate through line 56 andrecycled therein to the ketodioxane feed line 46 for reuse in the process.

The eifica'cy of the separations obtained in the examples below 'are 'deinonstr'ate'dby reference to mixed aniline point and torefractive-index. The mixed aniline point in each case was determined according to ASTM method;D-10125 1. The method consists of mixing together one part by volume of the sample being tested, one part by volume'of-normal-heptane and two parts by volume of aniline, :and then observing 'the temperature at which the mixture changes vfrom one homogenous solution to two liquid phases, this temperature being the so-called mixed aniline poin The mixed aniline point is considered indicative of aromaticity, inasmuch as aromatic hydrocarbons have relatively lower mixed aniline points, and nonaromatic hydrocarbons have relatively higher mixed aniline points. For example, the mixed aniline point of normal-heptane is 69 C., of methylcyclohexane is 54 C., of transdecalin is 50 C., of 1- methylnaphthalene is 13 C., of toluene is C. and of tetralin is 9 C.

The refractive index is also considered indicative of aromaticity, with the more aromatic hydrocarbons having relatively higher refractive indexes. The refractive index, n of normal-heptane is 1.3875, of methylcyclohexane is 1.4225, of toluene is 1.4950, of trans-decalin is 1.4700, of tetralin is 1.5461, and of l-methylnaphthalene is 1.6180.

Example I The hydrocarbon mixture separated was a neutral light oil derived from coal hydrogenation. It had a refractive index, 11 of 1.5120 and a mixed aniline point of 323 C. It contained 26 percent by weight of aliphatic hydrocarbons and 75 percent aromatic hydrocarbons.

The equipment comprised a l2-stage, 2 inch inside diameter York-Scheibel extraction column. The temperature of the materials during the extraction process was fmaintain'ed rat 50 C. The feed to the extraction column was 2 parts of volume -'of ketodioxane to one part 'by volume of hydrocarbon mixture. The ketodioxane extract from the column was found to contain '65 percentrby weight 'of the hydrocarbon mixture with the other 35 apercentby weight remaining as raffinate.

'When L1 800.milliliters ofwater was added to 2808 grams of the extract an aromatic hydrocarbon phase separated. After being washedwith water this aromatic hydrocarbon extract phase amounted to 550 grams. It :had a'refractive index of 1.5418 and a mixed aniline point of 18.4 C. This aromatic hydrocarbon extract .contain'ed'98 percent by weight o'f aromatic hydrocarbons and only 'tWmperce'nt by weight of aliphatic hydrocarbons. The water phase rofxthe extract was washed with hexane to remove residual hydrocarbons and then distilled. Ketodioxane in the amount of 1900 grams was recovered as distillate.

The raflinate remaining after :the extraction with ketodioxane :had -a refractive index of 1.4613 and amixed aniline .point of 515 .C. .It consisted. of '58 percent by weight of aliphatic hydrocarbons and 42 percent aromatic. hydrocarbons.

Example 11 The hydrocarbon mixture separated consisted of 56 percent by -Wight=.0f benzene and 44 percent by weight of n-heptane. The ketodioxane employed as extractant had a freezing point of 24.8 C.

The equipment comprised a four foot long, 11 stage, 1 inch inside diameter York-Scheibel extraction column. The temperature of the materials during the extraction process was :maintained at 40 C. The feed to -the extraction column was 2 parts by volume of ketodioxane to :1 part by volume of hydrocarbon mixture. Feed to the extraction column was commenced'and the column was allowed to come to equilibrium. Then'while 776 .grams (1000 milliliters) of the hydrocarbon mixture was extracted with2534 grams (.2000 milliliters) of ketodioxane,.there was obtained from the column 2927 grams ofextract and 306 grams of rafiinate.

The extract was charged to a laboratory still having a 2 foot by 1 inch inside diameter column, and the extract was distilled ata reflux ratio of 3 to 1 until the distillationtemperature began to rise rapidly above C. The .distillate up to this point, being the material extracted by the ketodioxane from the original hydrocarbon mixture, amounted to 448 grams and contained 93 percent by Weight of benzene and only 7 percent by weight of heptane. The distillation was continued to recover the ketodioxane and 2327 grams of ketodioxane, having a freezing point of 26.5 C., was recovered.

The composition of the rafiinate from the extraction, on a solvent-free basis, was 98 percent by weight of heptane and only 2 percent by weight of benzene.

Example III The hydrocarbon mixture separated was a neutral light oil derived from coal hydrogenation. That fraction of the mixture having a boiling temperature between C. and 260 C. was analyzed and found to have a refractive index, 21 of 1.5113 and a mixed aniline point of 328 C. It contained 26 percent by weight of aliphatic hydrocarbons and 74 percent of aromatic hydrocarbons.

The equipment comprised a four foot long 1l-stage, 1 inch inside diameter York-Scheibel extraction column. The temperature of the materials during the extraction process was maintained at 50 C. The feed to the extraction column was 3 parts by volume by ketodioxane to 1 part by volume of hydrocarbon mixture. Feed to the extraction column was commenced and the column was allowed to come to equlibrium. Then while 901 grams (1 liter) of the hydrocarbon mixture was extracted with 3735 grams (3 liters) of ketodioxane, there '7 was obtained from the column 4228 grams of extract and 360 grams of rafiinate.

The extract was back-extracted, in the same type of column as that used for the original extraction, with n-heptane at a n-heptane to feed ratio of 2 to 1 so as to recover the aromatic hydrocarbons which had been extracted by the ketodioxane. The n-heptane was distilled from the n-heptane extract and the residue was washed with water, leaving 515 grams of aromatic hydrocarbons. The fraction of the material boiling between 120 C. and 260 C. was analyzed and found to have a refractive index of 1.5452 and a mixed aniline point of l7.4 C. It contained 97 percent by Weight of aromatic hydrocarbons and only 3 percent by weight of aliphatic hydrocarbons. The ketodioxane raifinate from the nheptane back-extraction was found to have a freezing point of 25.5 C. and to be suitable recycle in the process.

The aliphatic hydrocarbon rafiinate from the. original ketodioxane extraction was washed with water to remove any traces of ketodioxane. The fraction of it boiling between 120 C. and 260 C. was analyzed and found to have a refractive index of 1.4605 and a mixed aniline point of 53.2 C. It contained 61 percent by weight of aliphatic hydrocarbons.

Further examples of the eflicacy of ketodioxane as a selective solvent for extracting an aromatic compound from admixture with an aliphatic compound are to be seen in the results plotted in Figures 4, 5 and 6 of the drawing. Each of these figures is a ternary diagram representing the relative miscibility of ketodioxane with an aliphatic and an aromatic compound. The data for these figures was all gathered at a temperature of about 25 C. These ternary diagrams clearly demonstrate to one skilled in the art the efiiciency of ketodioxane in the aforesaid extractive separation.

What is claimed is:

1. Process for separating a more aromatic hydrocarbon fraction from admixture with a less aromatic hydrocarbon fraction which comprises extracting said more aromatic fraction with ketodioxane to leave said less aromatic fraction as product and recovering said more aromatic fraction from the extract thus obtained.

2. Process for separating a more aromatic hydrocarbon fraction from admixture with a less aromatic hydrocarbon fractionwhich comprises extracting said more aromatic fraction with ketodioxane to leave said less aromatic fraction as product and distilling said more aromatic fraction from the extract thus obtained.

3. Process for separating a more aromatic hydrocarbon fraction from admixture with a less aromatic hydrocarbon fraction which comprises extracting said more aromatic fraction with ketodioxane to leave said less aromatic fraction as product, back-extracting the first extract thus obtained with an aliphatic naphtha to remove the more aromatic fraction as a second extract and distilling said naphtha from said second extract to leave said more aromatic fraction as product.

4. Process for separating a more aromatic hydrocarbon fraction from admixture with a less aromatic hydrocarbon fraction which comprises extracting said more aromatic fraction with ketodioxane to leave said less aromatic fraction as product, diluting the first extract thus obtained with water and thereby hydrolyzing the ketodioxane to (Z-hydroxyethoxy) acetic acid, separating the thus formed aromatic hydrocarbon phase from the thus formed water-acid phase and recovering said aromatics as product.

5. Process for separating a more aromatic hydrocarbon fraction from admixture with a less aromatic hydrocarbon fraction which comprises extracting said more aromatic fraction with ketodioxane to leave said less aromatic fraction as product, diluting the first extract thus obtained with water and thereby hydrolyzing the ketodioxane to (Z-hydroxyethoxy) acetic acid, separating the thus formed aromatic hydrocarbon phase from the thus formed water-acid phase, and distilling the wateracid phase to recover ketodioxane as distillate and recovering said aromatics as product.

References Cited in the file of this patent UNITED STATES PATENTS 2,568,159 Medcalf et al. Sept. 18, 1951 2,568,176 Vriens et al. Sept. 18, 1951 FOREIGN PATENTS 413,307 Great Britain July 11, 1934 472,767 Great Britain Sept. 30, 1937 OTHER REFERENCES Ham: Ind. and Eng. Chem., vol. 46, pp. 390-392, 1954. (Copy in Patent Ofiice Library.)

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2568159 *Feb 10, 1950Sep 18, 1951American Cyanamid CoRecovery of dicyanodialkyl ethers and sulfides used as solvents in an aromatic hydrocarbon extraction process
US2568176 *Feb 10, 1950Sep 18, 1951American Cyanamid CoRecovery of dinitrile solvents
GB413307A * Title not available
GB472767A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3072568 *Mar 28, 1960Jan 8, 1963Marathon Oil CoSelective solvent extraction process in the gas-oil range
US4498980 *Feb 14, 1983Feb 12, 1985Union Carbide CorporationOlvent extraction using mixture of polyalkylene glycol and glycolether
US4571295 *May 13, 1983Feb 18, 1986Union Carbide CorporationSolvent extraction
Classifications
U.S. Classification585/839, 585/840, 208/321, 585/865, 208/325
International ClassificationC10G21/16, C07C7/10
Cooperative ClassificationC10G21/16, C07C7/10
European ClassificationC07C7/10, C10G21/16