Methylcyclohexane/toluene/phenol

Determination of stage requirements for extractive distillation follows the approaches discussed in Section 5.3. It is necessaiy to have vapor-liquid equilibrium data, and these are measured conventionally. A representative relation between solvent/nonsolvent ratio and relative volatility is shown in Rg. 5.5-4, taken from the papers of Oerster and Drickamer et al. From the figure it is clear that vatious combinations of solvent content and stage requirements are possible, and the optimum solvent ratio must be determined. Figure 5.5-4 deals with the separation of toluene fium methylcyclohexane using phenol as the solvem. The natural volatility of the binaiy mixture is shown as the bottom line (no phenol presem) and the enhancement of this volatility by phenol addition is significant. A ffow diagram of this separation process te shown in Fig. 5.5-5. 

EINECS 203-468-6, see Ethylenediamine EINECS 203-470-7, see Allyl alcohol EINECS 203-472-8, see Chloroacetaldehyde EINECS 203-481-7, see Methyl formate EINECS 203-523-4, see 2-Methylpentane EINECS 203-528-1, see 2-Pentanone EINECS 203-544-9, see 1-Nitropropane EINECS 203-545-4, see Vinyl acetate EINECS 203-548-0, see 2,4-Dimethylpentane EINECS 203-550-1, see 4-Methyl-2-pentanone EINECS 203-558-5, see Diisopropylamine EINECS 203-560-6, see Isopropyl ether EINECS 203-561-1, see Isopropyl acetate EINECS 203-564-8, see Acetic anhydride EINECS 203-571-6, see Maleic anhydride EINECS 203-576-3, see m-Xylene EINECS 203-598-3, see Bis(2-chloroisopropyl) ether EINECS 203-604-4, see 1,3,5-Trimethylbenzene EINECS 203-608-6, see 1,3,5-Trichlorobenzene EINECS 203-620-1, see Diisobutyl ketone EINECS 203-621-7, see sec-Hexyl acetate EINECS 203-623-8, see Bromobenzene EINECS 203-624-3, see Methylcyclohexane EINECS 203-625-9, see Toluene EINECS 203-628-5, see Chlorobenzene EINECS 203-630-6, see Cyclohexanol EINECS 203-632-7, see Phenol EINECS 203-686-1, see Propyl acetate EINECS 203-692-4, see Pentane EINECS 203-694-5, see 1-Pentene EINECS 203-695-0, see cis-2-Pentene EINECS 203-699-2, see Butylamine EINECS 203-713-7, see Methyl cellosolve EINECS 203-714-2, see Methylal EINECS 203-716-3, see Diethylamine EINECS 203-721-0, see Ethyl formate EINECS 203-726-8, see Tetrahydrofuran EINECS 203-729-4, see Thiophene EINECS 203-767-1, see 2-Heptanone EINECS 203-772-9, see Methyl cellosolve acetate EINECS 203-777-6, see Hexane EINECS 203-799-6, see 2-Chloroethyl vinyl ether EINECS 203-804-1, see 2-Ethoxyethanol EINECS 203-806-2, see Cyclohexane EINECS 203-807-8, see Cyclohexene EINECS 203-809-9, see Pyridine EINECS 203-815-1, see Morpholine EINECS 203-839-2, see 2-Ethoxyethyl acetate EINECS 203-870-1, see Bis(2-chloroethyl) ether EINECS 203-892-1, see Octane EINECS 203-893-7, see 1-Octene EINECS 203-905-0, see 2-Butoxyethanol EINECS 203-913-4, see Nonane EINECS 203-920-2, see Bis(2-chloroethoxy)methane EINECS 203-967-9, see Dodecane EINECS 204-066-3, see 2-Methylpropene EINECS 204-112-2, see Triphenyl phosphate EINECS 204-211-0, see Bis(2-ethylhexyl) phthalate EINECS 204-258-7, see l,3-Dichloro-5,5-dimethylhydantoin... 

The results obtained in the solution of a sample problem are summarized here to illustrate the application of the method. An extractive distillation problem from Oliver (6) was used in which methylcyclo-hexane is separated from toluene by adding phenol. The column contains 11 stages (including the reboiler and condenser) and has a feed of 0.4 moles/unit time of methylcyclohexane and 0.6 moles/unit time of toluene to the fourth stage from the reboiler and 4.848 moles/unit time of phenol to the fourth stage from the condenser. We used the same physical property correlations as Oliver. The activity coefficients were obtained from a multicomponent form of the Van Laar Equation (7). 

Figure 13.24. Composition profiles and flowsketches of two extractive distillation processes, (a) Separation of methylcyclohexane and toluene with phenol as solvent (data calculated by Smith, 1963). (b) Separation of aqueous ethanol and isopropanol, recovering 98% of the ethanol containing 0.2 mol % isopropanol, employing water as the solvent. Flow rates are in mols/hr (data calculated by Robinson and Gilliland, 1950).

Typical mixtures that can be separated by extractive distillation in processes similar to the one described above include cyclohexane and benzene, and toluene and methylcyclohexane, both using phenol as the solvent. In another process, isobutane and 1-butene are separated using furfural as the solvent. 

An example of an extractive distillation process is the separation of methylcyclohexane (MCH) from toluene using a phenol solvent, as shown in Figure 12.17. Since MCH boils at 101.0°C and toluene boils at 110.7°C (1 atm), their separation by ordinary distillation is very difficult even though they do not form an azeotrope. Phenol is an effective solvent, since it has a structure more similar to the aromatic than to MCH (a naphthene), and it is relatively nonvolatile. The rectification... 

A new Rh catalyst [Rh/A10(OH)] that is recyclable (can be recovered simply by filtration and reused 10 times without activity loss) and highly active in the hydrogenation of arenes was synthesized from RhClj HjO, 2-butanol, and Al(0- cc-Bu)j and then entrapped in a highly porous and fibrous boehmite matrix. The particle size of Rh was estimated to be 2.5-3.Onm. The catalyst was highly active at room temperature under 1 atm for monosubstituted arenes such as toluene (80), phenol (82), and ethyl benzoate (84). Methylcyclohexane (81) and cyclohexanol (83) were... 

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