Abstract:
The higher boiling ketone isomers are difficult to separate one from another by conventional distillation or rectification because of the close proximity of their boiling points. Ketone isomers can be readily separated from each other by extractive distillation. Typical examples of effective agents are: for 3-pentanone from 2-pentanone, dipropylene glycol; 3-hexanone from 2-hexanone, butoxypropanol; 3-heptanone from 2-heptanone, 50% ethylene glycol--50% butoxypropanol; 3-octanone from 2-octanone, ethylene glycol diacetate.

Description:
FIELD OF THE INVENTION 
     This invention relates to a method for separating ketone isomers one from another using certain higher boiling liquids as the agent in extractive distillation. 
     DESCRIPTION OF PRIOR ART 
     Extractive distillation is the method of separating close boiling compounds from each other by carrying out the distillation in a multiple rectification column in the presence of an added liquid or liquid mixture, said liquid(s) having a boiling point higher than the compounds being separated. The extractive agent is introduced near the top of the column and flows downward until it reaches the stillpot or reboiler. Its presence on each plate of the rectification column alters the relative volatility in a direction to make the separation on each plate greater and thus require either fewer plates to effect the same separation or make possible a greater degree of separation with the same number of plates. The extractive agent should boil higher than any of the close boiling liquids being separated and not form minimum azeotropes with them. Usually the extractive agent is introduced a few plates from the top of the column to insure that none of the extractive agent is carried over with the lowest boiling compound. This usually requires that the extractive agent boil twenty Centrigrade degrees or more above the lowest boiling component. 
     At the bottom of a continuous column, the less volatile components of the close boiling mixture and the extractive agent are continuously removed from the column. The usual methods of separation of these two components are the use of another rectification column, cooling and phase separation or solvent extraction. 
     Extractive distillation typically requires the addition of an equal amount to twice as much extractive agent as the ketone isomer mixture on each plate of the rectification column. The extractive agent should be heated to about the same temperature as the plate into which it is introduced. Thus extractive distillation imposes an additional heat requirement on the column as well as somewhat larger plates. However this is less than the increase caused by the additional agents requires if the separation is done by azeotropic distillation. Another consideration in the selection of the extractive distillation agent is its recovery from the bottoms product. The usual method is by rectification in another column. In order to keep the cost of this operation to a minimum, an appreciable boiling point difference between the compound being separated and the extractive agent is desirable. It is also desirable that the extractive agent be miscible with the extracted ketone otherwise it will form a two-phase azeotrope with the extracted ketone in the recovery column and some other method of separation will have to be employed. 
     In the manufacture of the higher ketones, the process frequently yields a mixture of isomers. Depending upon the number of isomers and the difference in their molecular structure, the boiling points of some isomers can be very close together. The closest boilers in a series of isomeric ketones are listed as follows for their boiling points and relative volatilities: 2-pentanone, B.P.=100° C., 3-pentanone, B.F.=102° C., rel. vol.=1.02; 3-hexanone, B.P.=123° C., 2-hexanone, B.P.=127° C., rel. vol.=1.15; 3-heptanone, B.P.=146° C., 2-heptanone, B.P.+146° C., rel. vol.=1.17; 3-octanone, B.P.=168° C., 2-octanone, B.P.=173° C., rel. vol.=1.15. 
     
                       TABLE 1______________________________________Plates Required To Effect Separation Of 99% PurityRelative     Theoretical                  Actual Plates,Volatility   Plates    75% Efficiency______________________________________1.02         465       6201.15         66        881.17         59        791.25         41        551.30         35        471.35         31        411.40         27        36______________________________________ 
    
     Table 1 shows that to separate a mixture having a relative volatility of 1.15, 66 theoretical or 88 actual plates would be required to separate in 99% purity. If the relative volatility could be improved to 1.3, only 47 actual plates would be required and with a relative volatility of 1.4, only 36 actual plates are needed. 
     Extractive distillation would be an attractive method of effecting the separation of ketone isomers one from another, if agents can be found that (1) will increase the relative volatility of one isomer to the other and (2) are easy to recover from the ketone being extracted, that is, form no azeotrope with ketone and boil sufficiently above it to make separation by rectification possible with only a few plates. 
     Pacoud &amp; Dallemagne, U.S. Pat. No. 3,013,954 described the use of an auxiliary substance to separate the ketone acetone from acetic acid, formic acid, formaldehyde and water. The auxiliary substance used was isopropyl ether. 
     Carpenter, Taylor &amp; McNair, U.S. Pat. No. 3,228,985 described the use of aqueous sodium carbonate in a solvent extraction process to recover methyl ethyl ketone from a complex mixture of water, acids, alcohols, ketone and esters. Van Melsen &amp; Langedijk, U.S. Pat. No. 2,010,384 described a process for separating isomeric pentanones using a water soluble bisulfite as the agent in a solvent extraction method. 
     OBJECTIVE OF THE INVENTION 
     The object of this invention is to provide a process or method of extractive distillation that will enhance the relative volatility of ketone isomers one from another in their separation in a rectification column. It is a further object of this invention to identify organic compounds which in addition to the above constraints, are stable, can be separated from the ketone being extracted by rectification with relatively few plates and can be recycled to the extractive distillation column and reused with little decomposition. 
     SUMMARY OF THE INVENTION 
     The objects of the invention are provided by a process for separating ketone isomers one from another which entails the use of certain glycols, either alone or admixed with certain high boiling organic compounds in an extractive distillation. 
     DETAILED DESCRIPTION OF THE INVENTION 
     3-Pentanone From 2-Pentanone: 
     We have discovered that certain glycols, either alone or admixed with certain high boiling organic compounds will effectively enhance the relative volatility of 3-pentanone to 2-pentanone by rectification when employed as the agent in extractive distillation. Table 2 lists the glycols and certain high boiling organic compounds that we have found to be effective. 
     The glycols and mixtures which are effective in the separation of 3-pentanone from 2-pentanone are propylene glycol, 1,3-butanediol, 1,2-butanediol, triethylene glycol, tetraethylene glycol, dipropylene glycol, hexylene glycol, 1,4-butanediol, polyethylene glycol 200, 2-methyl-1,3-propanediol, 50% ethylene glycol, 50% propoxypropanol, 67% ethylene glycol, 33% dipropylene glycol and 67% ethylene glycol, 33% polyethylene glycol 200. 
     Three compounds, namely triethylene glycol, 1,4-butanediol and dipropylene glycol, whose relative volatility had been determined in a vapor-liquid equilibrium still and reported in Table 2, were then evaluated in a glass perforated plate rectification column possessing 7.3 theoretical plates. The results are listed in Table 4 and show that triethylene glycol gave a relative volatility of 1.167, 1,4-butanediol gave 1.25 and dipropylene gave 1.63. 
     Table 3 lists several glycols that might have been expected to be effective but which were not. 
     
                       TABLE 2______________________________________Effective Agents For Separating 3-Pentanone From 2-Pentanone                      RelativeCompounds                  Volatility______________________________________None                       1.0250% Ethylene glycol, 50% Propoxypropanol                      1.14Propylene glycol           1.181,3-Butanediol             1.311,2-Butanediol             1.29Triethylene glycol         1.22tetraethylene glycol       1.19Dipropylene glycol         1.30hexylene glycol            1.151,4-Butanediol             1.25Polyethylene glycol 200    1.3067% Ethylene glycol, 33% Dipropylene glycol                      1.1767% Ethylene glycol, 33% polyethylene glycol 200                      1.302-Methyl-1,3-propanediol   1.30______________________________________ 
    
     
                       TABLE 3______________________________________Ineffective Agents For Separating 3-Pentanone From 2-Pentanone              RelativeCompounds          Volatility______________________________________1,5-Pentanediol    1.021,6-Hexanediol     1.08Diethylene glycol  1.06Tripropylene glycol              1.03Polyethylene glycol 300              1.04______________________________________ 
    
     
                       TABLE 4______________________________________Data From Runs Made in Rectification Column -3-Pentanone From 2-Pentanone                     Weight Weight              Time   % 3-Pen-                            % 2-Pen-                                   RelativeAgent    Column    hrs.   tanone tanone Volatility______________________________________Triethylene    Overhead  1.5    58.7   41.3    1.167glycol   Bottoms          31.4   68.61,4-     Overhead  2      72.1   27.9   1.25Butanediol    Bottoms          33.5   66.5Dipropylene    Overhead  1      98.7    1.3   1.63glycol   Bottoms          67.3   32.7______________________________________ 
    
     3-Hexanone From 2-Hexanone: 
     We have discovered that certain oxygenated organic compounds will effectively enhance the relative volatility of 3-hexanone to 2-hexanone when employed as the agent in extractive distillation. Table 5 lists the compounds that we have found to be effective. The relative volatilities shown in Table 5 were obtained in an Othmer type vapor-liquid equilibrium still. The compounds and mixture which are effective in the separation of 3-hexanone from 2-hexanone are triethylene glycol, dipropylene glycol methyl ether, n-octanol, ethylene glycol diacetate, diethylene glycol hexyl ether, benzyl alcohol, tripropylene glycol methyl ether, butoxypropanol, propoxypropanol, sulfolane, benzonotrile and 50% ethylene glycol--50% butoxypropanol. 
     
                       TABLE 5______________________________________Effective Agents For Separating 3-Hexanone From 2-Hexanone                RelativeCompounds            Volatility______________________________________None                 1.15Ethylene glycol, Butoxypropanol                1.27Triethylene glycol   1.22Dipropylene glycol methyl ether                1.25Ethylene glycol diacetate                1.20Diethylene glycol hexyl ether                1.23n-Octanol            1.23Tripropylene glycol methyl ether                1.27Butoxypropanol       1.28Propoxypropanol      1.33Sulfolane            1.22Benzyl alcohol       1.23Benzonitrile         1.28______________________________________ 
    
     
                       TABLE 6______________________________________Ineffective Agents For Separating 3-Hexanone From 2-Hexanone                RelativeCompounds            Volatility______________________________________Propylene glycol     1.16Ethylene glycol hexyl ether                1.10Diethylene glycol methyl ether                1.16Glycerol triacetate  1.19Diethylene glycol butyl ether                1.19Isononyl alcohol     1.17Dodecanol            1.18Nitrobenzene         1.132-Nitrotoluene       1.013-Nitrotoluene       1.142-Methylpyrrolidone  1.13o-tert. Butyl phenol 1.12Phenol               1.19Ethyl acetoacetate   1.17______________________________________ 
    
     
                       TABLE 7______________________________________Data From Run Made In Rectification Column -3-Hexanone From 2-Hexanone                     Weight Weight              Time   % 3-Hex-                            % 2-Hex-                                   RelativeAgent    Column    hrs.   anone  anone  Volatility______________________________________Butoxypro-    Overhead  1      71.5   28.5   1.32panol    Bottoms          25.8   74.2Butoxypro-    Overhead  2      70.2   29.8   1.31panol    Bottoms          24.4   75.6______________________________________ 
    
     Table 6 lists several compounds that might have been expected to be effective but which were not. 
     One compound, butoxypropanol, whose relative volatility had been determined in the vapor-liquid equilibrium still and reported in Table 5, was then evaluated in a glass perforated plate rectification column possessing 7.3 theoretical plates. The results are listed in Table 7 and show that butoxypropanol gave a relative volatility of 1.31. 
     3-Heptanone From 2-Heptanone: 
     We have discovered that certain oxygenated organic compounds will effectively enhance the relative volatility of 3-heptanone to 2-heptanone when employed as the agent in extractive distillation. Table 8 lists the compounds that we have found to be effective. The relative volatilities shown in Table 8 were obtained in an Othmer type vapor-liquid equilibrium still. The compounds and mixtures which are effective in the separation of 3-heptanone from 2-heptanone are propylene glycol, triethylene glycol, hexylene glycol, 1,2-butanediol ethylene glycol-butoxypropanol, diethylene glycol-butoxypropanol, propylene glycol-butoxypropanol, 1,4-butanediol-butoxypropanol and nitrobenzene-butoxypropanol. Table 9 lists several compounds and mixtures that might have been expected to be effective but which were not. One mixture, 50% ethylene glycol, 50% butoxypropanol, whose relative volatility had been determined in the vapor-liquid equilibrium still and reported in Table 8, was then evaluated in a glass perforated plate rectification column possessing 7.3 theoretical plates. The results are listed in Table 10 and show that 50% ethylene glycol--50% butoxypropanol gave a relative volatility of 1.28. 
     3-Octanone From  2-Octanone: 
     We have discovered that certain oxygenated organic compounds will effectively enhance the relative volatility of 3-octanone to 2-octanone when employed as the agent in extractive distillation. Table 11 lists the compounds and mixtures that we have found to be effective. The relative volatilities shown in Table 11 were obtained in an Othmer type vapor-liquid equilibrium still. The compounds and mixtures which are effective are ethylene carbonate, propylene carbonate, sulfolane, 2-hydroxyacetophenone, tripropylene glycol methyl ether, ethylene glycol hexyl ether, ethylene glycol diacetate, dipropylene glycol methyl ether, benzonitrole, n-(2-hydroxyethyl-2-pyrrolidone, butoxyethoxy-2-propanol, diethylene glycol hexyl ether, triethylene glycol-diethylene glycol butyl ether and polyethylene glycol 200--tripropylene glycol methyl ether. 
     
                       TABLE 8______________________________________Effective Agents For Separating 3-Heptanone From 2-Heptanone                 RelativeCompounds             Volatility______________________________________None                  1.17Propylene glycol      1.29Triethylene glycol    1.28Hexylene glycol       1.231,2-Butanediol        1.24Ethylene glycol, Butoxypropanol                 1.28Diethylene glycol, Butoxypropanol                 1.26Propylene glycol, Butoxypropanol                 1.251,4-Butanediol, Butoxypropanol                 1.27Nitrobenzene, Butoxypropanol                 1.28______________________________________ 
    
     
                       TABLE 9______________________________________Ineffective Agents For Separating3-Heptanone From 2-Heptanone                 RelativeCompounds             Volatility______________________________________Dimethylsulfoxide     1.18Dimethylacetamide     1.10Adiponitrile          1.121,2-Butanediol, Butoxypropanol                 1.161,3-Butanediol, Butoxypropanol                 1.101,5-Pentanediol, Butoxypropanol                 1.121,6-Hexanediol        1.20Dipropylene glycol    1.05Tripropylene glycol   1.19Polyethylene glycol 200                 1.21Polyethylene glycol 300                 1.18Butoxypropanol        1.14Tetraethylene glycol  1.182-Methoxymethyl ether 1.002-Nitrotoluene, Butoxypropanol                 1.183-Nitrotoluene        1.154-Nitrotoluene        1.13______________________________________ 
    
     
                       TABLE 10______________________________________Data From Run Made In Rectification Column -3-Heptanone From 2-Heptanone                     Weight Weight              time   % 3-Hep-                            % 2-Hep-                                   RelativeAgent    Column    hrs.   tanone tanone Volatility______________________________________50% Ethyl-    Overhead  1      74     26     1.262ene glycol,    Bottoms          33.9   66.150% Butoxy-propanol50% Ethyl-    Overhead  1.7    73.8   26.2   1.28ene glycol,    Bottoms          32     6850% Butoxy-propanol______________________________________ 
    
     
                       TABLE 11______________________________________Effective Agents For Separating 3-Octanone From 2-Octanone                  RelativeCompounds              Volatility______________________________________None                   1.15Ethylene carbonate     1.25Propylene carbonate    1.232-Hydroxyacetophenone  1.22Sulfolane              1.23Tripropylene glycol methyl ether                  1.25Ethylene glycol hexyl ether                  1.24Ethylene glycol diacetate                  1.28Dipropylene glycol methyl ether                  1.21Benzonitrile           1.20N-(2-Hydroxyethyl-2-Pyrrolidone)                  1.21Triethylene glycol, Diethylene glycol                  1.20butyl etherPolyethylene glycol 200, Tripropylene                  1.23glycol methyl etherButoxyethoxy-2-propanol                  1.24Diethylene glycol hexyl ether                  1.28______________________________________ 
    
     
                       TABLE 12______________________________________Ineffective Agents For Separating 3-Octanone From 2-Octanone                 RelativeCompounds             Volatility______________________________________Adiponitrile          1.14Butyl benzoate        1.11Dihexyl phthalate     1.03Methyl salicylate     1.09Pelargonic acid       1.16Polyethylene glycol 200                 1.19Polyethylene glycol 300                 1.15Diethylene glycol butyl ether                 1.18Glycerol triacetate   1.08Diethylene glycol diethyl ether                 1.06Ethyl acetoacetate    1.15Diethylene glycol methyl ether                 1.14Diethyl malonate      1.10Triisononyl trimellitate                 1.13N-Methyl-2-pyrrolidone                 1.16N-Cyclohexyl-2-pyrrolidone                 1.02Diisononyl adipate    1.19Tridecyl phthalate    1.10Tributyl phosphate    1.16Tri-2-Ethyl hexyl trimellitate                 1.09Ethylene glycol phenyl ether                 1.192-Ethyl hexyl acetate 1.17Diisodecyl phthalate  1.15Tetraethylene glycol, Tripropylene                 1.16glycol methyl etherPropylene carbonate, n-Methyl-2-                 1.13pyrrolidone______________________________________ 
    
     
                       TABLE 13______________________________________Data From Runs Made In Rectification Column -3-Octanone From 2-Octanone                     Weight Weight              Time   % 3-   % 2-   RelativeAgent    Column    hrs.   Octanone                            Octanone                                   Volatility______________________________________Dipropylene    Overhead  2      38.6   61.4   1.20glycol methyl    Bottoms          14.1   85.9etherDipropylene    Overhead  3      39.6   60.4   1.21glycol methyl    Bottoms          14.4   85.6etherEthylene gly-    Overhead  1      54.4   45.6   1.36col diacetate    Bottoms          11.1   88.9Ethylene gly-    Overhead  2      57.6   42.4   1.39col diacetate    Bottoms          10.7   89.3______________________________________ 
    
     Table 12 lists several compounds and mixtures that might have been expected to be effective but which were not. 
     Two compounds, dipropylene glycol methyl ether and ethylene glycol diacetate, whose relative volatilities had been determined in the vapor-liquid equilibrium still and reported in Table 11, were then evaluated in a glass perforated plate rectification column possessing 7.3 theoretical plates. The results are listed in Table 13 and show that dipropylene glycol methyl ether gave a relative volatility of 1.21 and ethylene glycol diacetate gave a relative volatility of 1.39. 
     THE USEFULNESS OF THE INVENTION 
     The usefulness or utility of this invention can be demonstrated by referring to the data presented in Tables 1-13. All of the successful extractive agents show that ketone isomers can be separated one from another by means of distillation in a rectification column and that the ease of separation as measured by relative volatility is considerable. Without these extractive distillation agents, only slight improvement will occur in a rectification column. The data also show that the most attractive agents will operate at a boilup rate low enough to make this a useful and efficient method of recovering high purity ketone from any mixture of ketone isomers. The stability of the compounds used and the boiling point difference is such that complete recovery and recycle is obtainable by a simple distillation and the amount required for make-up is small. 
    
    
     WORKING EXAMPLES 
     EXAMPLE 1 
     Ten grams of 3-pentanone, 40 grams of 2-pentanone and 20 grams of 1,3-butanediol were charged to an Othmer type vapor-liquid still and refluxed for six hours. Analysis by gas chromatography gave a vapor composition of 19.2% 3-pentanone, 80.8% 2-pentanone; a liquid composition of 15.4% 3-pentanone, 84.6% 2-pentanone which is a relative volatility of 1.31. 
     EXAMPLE 2 
     A glass perforated plate rectification column was calibrated with m-xylene and o-xylene which possesses a relative volatility of 1.11 and found to have 7.3 theoretical plates. A solution comprising 250 grams 3-pentanone and 50 grams of 2-pentanone was placed in the stillpot and heated. When refluxing began, an extractive agent comprising dipropylene glycol was pumped into the column at a rate of 15 ml/min. The boil-up rate was 20 ml/min. and the temperature of the extractive agent as it entered the column was 85° C. After establishing the feed rate of the extractive agent, the heat input to the m-xylene and o-xylene in the stillpot was adjusted to give a total reflux rate of 30-40 ml/min. After one hour of operation, the overhead and bottoms samples of approximately two ml. were collected and analysed by gas chromatography. The overhead analysis was 98.7% 3-pentanone, 1.3% 2-pentanone. The bottoms analysis was 67.3% 3-pentanone, 32.7% 2-pentanone. Using these compositions in the Fenske equation with the number of theoretical plates in the column being 7.3, gave an average relative volatility of 1.63. for each theoretical plate. This run is presented in Table 4. 
     EXAMPLE 3 
     Ten grams of 3-hexanone, 30 grams of 2-hexanone and 20 grams of tripropylene glycol methyl ether were charged to an Othmer type vapor-liquid equilibrium still and refluxed for 12 hours. Analysis by gas chromatography gave a vapor composition of 21.25 3-hexanone, 78.8% 2-hexanone; a liquid composition of 17.4% 3-hexanone, 82.6% 2-hexanone which is a relative volatility of 1.27. 
     EXAMPLE 4 
     A glass perforated plate rectification column was calibrated with m-xylene and o-xylene which possesses a relative volatility of 1.11 and found to have 7.3 theoretical plates. A solution comprising 200 grams of 3-hexanone and 100 grams of 2-hexanone was placed in the stillpot and heated. When refluxing began, an extractive agent comprising butoxypropanol was pumped into the column at a rate of 15 ml/min. The boil-up rate was 20 ml/min. and the temperature of the extractive agent as it entered the column was 85° C. After establishing the feed rate of the extractive agent, the heat input to the m-xylene and o-xylene in the stillpot was adjusted to give a total reflux rate of 30-40 ml/min. After one hour of operation, the overhead and bottoms samples of approximately two ml. were collected and analysed by gas chromatography. The overhead analysis was 71.5% 3-hexanone, 28.5% 2-hexanone. The bottoms analysis was 25.8% 3-hexanone, 74.2% 2-hexanone. Using these compositions in the Fenske equation with the number of theoretical plates in the column being 7.3, gave an average relative volatility of 1.32 for each theoretical plate. This run is presented in Table 7. 
     EXAMPLE 5 
     Ten grams of 3-heptanone, 30 grams of 2-heptanone and 20 grams of triethylene glycol were charged to an Othmer type vapor-liquid equilibrium still and refluxed for five hours. Analysis by gas chromatography gave a vapor composition of 18.4% 3-heptanone, 81.6% 2-heptanone; a liquid composition of 15% 3-heptanone, 85% 2-heptanone which is a relative volatility of 1.28. 
     EXAMPLE 6 
     A glass perforated plate rectification column was calibrated with m-xylene and o-xylene which possesses a relative volatility of 1.11 and found to have 7.3 theoretical plates. A solution comprising 100 grams of 3-heptanone and 200 grams of 2-heptanone was placed in the stillpot and heated. When refluxing began, an extractive agent comprising 50% ethylene glycol, 50% butoxypropanol was pumped into the column at a rate of 15 ml/min. The boil-up rate was 20 ml/min. and the temperature of the extractive agent as it entered the column was 85° C. After establishing the feed rate of the extractive agent, the heat input to the m-xylene and o-xylene in the stillpot was adjusted to give a total reflux rate of 30-40 ml/min. After one hour of operation, the overhead and bottoms samples of approximately two ml. were collected and analysed by gas chromatography. The overhead analysis was 74% 3-heptanone, 26% 2-heptanone. The bottoms analysis was 33.9% 3-heptanone, 66.1% 2-heptanone. Using these compositions in the Fenske equation with the number of theoretical plates in the column being 7.3, gave an average relative volatility of 1.26 for each theoretical plate. This run is presented in Table 10. 
     EXAMPLE 7 
     Ten grams of 3-octanone, 30 grams of 2-octanone and 20 grams of diethylene glycol hexyl ether were charged to an Othmer type vapor-liquid equilibrium still and refluxed for four hours. Analysis by gas chromatography gave a vapor composition of 13.15 3-octanone, 86.9% 2-octanone; a liquid composition of 10.5% 3-octanone, 89.5% 2-octanone which is a relative volatility of 1.28. 
     EXAMPLE 8 
     A glass perforated plate rectification column was calibrated with m-xylene and o-xylene which possesses a relative volatility of 1.11 and found to have 7.3 theoretical plates. A solution comprising 50 grams of 3-octanone and 250 grams of 2-octanone was placed in the stillpot and heated. When refluxing began, an extractive agent comprising ethylene glycol diacetate was pumped into the column at a rate of 15 ml/min. The boil-up rate was 20 ml/min. and the temperature of the extractive agent as it entered the column was 85° C. After establishing the feed rate of the extractive agent, the heat input to the m-xylene and o-xylene in the stillpot was adjusted to give a total reflux rate of 30-40 ml/min. After two hour of operation, the overhead and bottoms samples of approximately two ml. were collected and analysed by gas chromatography. The overhead analysis was 57.6% 3-octanone, 42.4% 2-octanone. The bottoms analysis was 10.7% 3-octanone, 89.3% 2-octanone. Using these compositions in the Fenske equation with the number of theoretical plates in the column being 7.3, gave an average relative volatility of 1.39 for each theoretical plate. This run is presented in Table 13.