N-Pentane benzene and diethyl ether

The methods used here to give the phase equilibria are reviewed, and the Azeotropic Distillation Program ADP/ADPLLE is described. Application of the program to calculate an azeotropic distillation problem is shown and discussed, and a sample computer output is given and is briefly discussed. Finally, calculated azeotropic distillation results are compared for dehydrating aqueous ethanol for the three entrainers, n-pentane, benzene, and diethyl ether. 

For the azeotropic dehydration of aqueous ethanol mixtures approaching the constant boiling mixture, a brief comparison is shown for the entrainers, n-pentane, benzene, and diethyl ether. Since water is most non-ideal in n-pentane, the driest ethanol is expected to be produced if n-pentane is used. 

Figure 6. Comparing entrainers, n-pentane, benzene, and diethyl ether, for water content of ethanol product...

The calculated results, comparing the water content of the ethanol product for the entrainers, n-pentane, benzene, and diethyl ether, are shown in Figure 6. The mole fraction water in the ethanol product is plotted vs. the entrainer-to-ethanol ratio, on a mole basis, n-Pentane produces ethanol of lowest water content benzene comes next, and diethyl ether comes last. Entrainer-to-ethanol ratios of 2.5-3.5, mole basis, are adequate when n-pentane or benzene is used for diethyl ether, the ratio must be above four. 

The maximum flow on any tray in the column is compared for the three entrainers, n-pentane, benzene, and diethyl ether, in Figure 8. At the high entrainer-to-ethanol ratio of 4.2, the maximum flow when n-pentane is used is about 70% of that for the case using diethyl ether. For the low ratio of about 3, the flows with n-pentane are about 75% of those using benzene. A smaller diameter column is required with n-pentane than with either of the other entrainers. 

Chemica Scand A 32, 675-680 (1978). Data for water are from CS Kell, J Chem Eng Data 20, 97 (1 975). Data for benzene, n-pentane and diethyl ether are from Landolt-Bornstein,... 

Capello et al.16 applied LCA to 26 organic solvents (acetic acid, acetone, acetonitrile, butanol, butyl acetate, cyclohexane, cyclohexanone, diethyl ether, dioxane, dimethylformamide, ethanol, ethyl acetate, ethyl benzene, formaldehyde, formic acid, heptane, hexane, methyl ethyl ketone, methanol, methyl acetate, pentane, n- and isopropanol, tetrahydrofuran, toluene, and xylene). They applied the EHS Excel Tool36 to identify potential hazards resulting from the application of these substances. It was used to assess these compounds with respect to nine effect categories release potential, fire/explosion, reaction/decomposition, acute toxicity, irritation, chronic toxicity, persistency, air hazard, and water hazard. For each effect category, an index between zero and one was calculated, resulting in an overall score between zero and nine for each chemical. Figure 18.12 shows the life cycle model used by Capello et al.16... 

Tetrabutylammonium tetrahydroborate(l —) is a white, crystalline solid, moderately stable in air at room temperature. It is soluble in methylene chloride, chloroform, methanol, ethanol, water, tetrahydrofuran, and benzene, but insoluble in diethyl ether and pentane. Its H nmr spectrum consists of [N(n-C4H9)4] + multiplets centered at t6.73, t8.49, and t9.03 and a sharp 1 1 1 1 quartet (t 10.17, JBH = 82 Hz) characteristic of [BH4) . The nB nmr spectrum is similar to that of [P(C6H5)3CH3][BH4]. 

This rule works best for apolar, quasi-spherical molecules. Large deviations occur when chemical association is involved [e.g. carboxylic acids), from molecular dipolarity [e.g. dimethyl sulfoxide), and from molecular asphericity e.g. neopentane/n-pentane). Strongly associating solvents e.g. HF, H2O, NH3, alcohols, carboxylic acids) have Trouton constants which are higher than the average value of 88 J mol K found for non-associating solvents such as diethyl ether and benzene. 

The differences between the propagation rate constants obtained by radiation in bulk and stable carbonium ion salts in methylene chloride solution described earlier led to a direct study of the effects of solvents. Details of this earlier work have been recently published with both EVE and IPVE. An excellent linear relationship between In. kp and 1/p was found as shown in Figure 7. The results were all obtained in 50 50 mixtures of monomer and solvent. The more recent and detailed work described in the previous section indicated, however, that polymerizations conducted in bulk, benzene, diethyl ether, diglyme, neopentane and in n-pentane all gave roughly similar rates, certainly within a factor of less than three. The dielectric constants of these solvents were all low, and diluted 50% with EVE only varied from about 2.7-3.3. In view of the substantial decrease in rate found with methylene chloride, this solvent was studied in more detail. 

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