Biphenyl solute retention

Solute retention as a function of pressure has been determined experimentally for a wide number of solutes over a range of temperatures and pressures.(1,23-25) The tcend in retention of a solute with pressure can be predicted within the limitations of our assumptions using eq. 11. The calculations are then compared with experimental data for the retention of naphthalene and biphenyl at various temperatures and pressures were obtained with supercritical CC. ... 

Table II. Retention of Biphenyl, Phenanthrene, and Pyrene in Aqueous Solutions during Vacuum Distillation and Lyophilization...

The experimental solubility for biphenyl in supercritical CC>2 at different temperatures as a function of pressure are shown in Figure 5.(22) The slopes of these plots were used to determine (alnX 0 /5P)T for biphenyl in supercritical CC, and these values were supplemented with solubilities predicted for lower pressures from theory as needed.(26) The experimental results of biphenyl at the temperatures 35.8°C, 45.5°C, and 55.28C are shown in Figures 6 and 7. The solid line in these figures is the theoretical prediction of the slope of the retention of the solute based on eq. 11 and the -stat... 

Two characteristics of macroporous supports are worth mentioning. First, the transfer of specific reaction conditions from solution to the macroporous support should be easier because the influence of swelling in different solvents and diffusion rates, typical for low-cross-linked PS resins, is not relevant. Second, this support can be washed more easily than the classical PS resins. A study of the retention of biphenyl in hydrophobic PS and AP-PS resins treated with solutions of biphenyl in methylene chloride (26) shows how after two identical wash cycles AP-PS retains 0.01% of biphenyl while hydrophobic PS retains 2.63% of the same impurity. This is due to the... 

The 50% phenyl-substituted sihcone and 30% biphenyl-substituted silicone stationary phases are moderately polar and contain polarizable aromatic rings that exhibit induced dipoles in the presence of dipolar solutes such as alcohols, phenols, amines, nitriles, ketones, and so forth. They give selectivity without extended retention of polar solutes because the dipole-induced-dipole interaction is relatively weak. Temperature affects the extent of this polarization and can be used as a variable in optimizing separations. 

Senn and Ziegler find the dissociative pathway to be the preferred one in their calculations in THF solution of the oxidative addition of chloro-, bromo- and iodobenzene to Pd(P-P) complexes, where P-P is a chelating diphosphine ligand of the type l,2-bis(dimethylphosphino)ethane or (P)-2,2 -bis(dimethylphosphino)-1,1 -biphenyl. The barriers from the prereaction complex are in fact quite low 31, 12 and 5 kJ/mol for the chloro, bromo and iodo species, respectively. For methyl-(lS,5R)-5-chlorocyclohex-3-ene-l-carboxylate in presence of neutral palladium, Espinet and Echavarren observed retention of configuration in apolar solvent (benzene) and inversion in polar solvent (acetonitrile) [13]. 

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