Direct optical resolution of the enantiomers of biphenyl compounds by high-performance liquid chromatography on cellulose tris-(3,5-dimethylphenylcarbamate) stationary phase

A chiral stationary phase (CSP) was prepared by coating cellulose - tris(3, 5 - dimethylphenylcarbamate) onto aminopropylated spherical silica gel. Th e enantioselective separation of a series of biphenyl compounds with antihe patitis activity was achieved for the first time on the CSP, using the norm al phase mode. The effects of temperature and concentration of ethanol in t he mobile phase on the chiral separation were studied. The retention factor s and separation factors for the enantiomers of all investigated compounds decreased with increasing temperature or increasing ethanol concentration i n the eluent. The natural logarithms of the separation factors (ln alpha) o f the investigated compounds depended linearly on the reciprocal of tempera ture (1/T). The thermodynamic parameters, such as the difference in enthalp y Delta (DeltaH degrees), entropy Delta(DeltaS degrees) and Gibbs free ener gy Delta(DeltaG degrees) for the transfer of analyte from the mobile phase to the CSP were calculated.