Benzene affinity distribution

By introducing reasonable values (about 2 for nitrogen, 4 for oxygen) for the electron affinity parameter relative to carbon, 8, and for the induced electron affinity for adjacent atoms (32/8i = Vio), we have shown that the calculated permanent charge distributions for pyridine, toluene, phenyltrimethylammonium ion, nitrobenzene, benzoic acid, benzaldehyde, acetophenone, benzo-nitrile, furan, thiophene, pyrrole, aniline, and phenol can be satisfactorily correlated qualitatively with the observed positions and rates of substitution. For naphthalene and the halogen benzenes this calculation does not lead to results... 

To increase the sorption component of the separation factor, homogeneously distributed tetracyanoethylene, a strong electron acceptor having high affinity for electron donors, was added to the polyimide matrix [77]. It can be seen from data presented in Table 9.12 that this is accompanied by an increase in the sorption component /3s (benzene/cyclohexane) by a factor of 1.5 probably as a result of selective sorption of aromatic compounds by tetracyanoethylene with a simultaneous increase in the diffusion component /3d. The prepared membranes showed good pervaporation properties with respect to benzene/cyclohexane, toluene/isooctane mixtures. For example, for a two-component 50/50 wt% benzene/cyclohexane mixture at 343 K, the flux was 2 = 0.44 kg p,m/m h, and /3p (benzene/cyclohexane) = 48 and for a two-component toluene/isooctane mixture, 45/55 wt%, at 343 K the flux was 2 = 1-1 kg p-m/m h, and /3p (toluene/wo-octane) = 330. 

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