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The formation of homochiral and heterochiral dimers in solutions of enantiomers causes a number of remarkable phenomena, such as the enantiomeric enrichment of nonracemic mixtures on achiral chromatographic columns when chiral monomers and dimers exhibit different retention behavior. In this work, such effects on optical rotation and UV absorbance are analyzed theoretically and experimentally. In particular, it is demonstrated how optical rotation measurements can be used to estimate the dimerization equilibrium constants. It is shown how significant this is for polarimeter calibration, as well as for the determination of enantiomer concentrations in process streams, when optical rotation and UV absorbance measurements are combined. All experimental measurements refer to the enantiomers of the chiral 2,2′-dihydroxy-1,1′-binaphthyl in chloroform, at a temperature of 23 °C. The measured values of its dimerization equilibrium constants are 1.3 ( 0.5 and 3.1 ( 1.0 L/mol for the formation of homochiral and of heterochiral dimers, respectively.

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The scale-up of the HPLC separation of the enantiomers of the flavour norterpenoid ketones˛-ionone and˛-damascone from analytical to preparative scale was achieved using the chromatographic simulated moving bed (SMB) technique. Commercial HPLC columns, with heptakis-(2,3,6-per-O-methyl)-ˇ-cyclodextrin bound to silica gel as chiral stationary phase, were employed for the separation. High-purity enantiomers of both chiral compounds have been obtained with a rather satisfactory productivity.