Phase Rejection as a Factor in the Kinetics of Atropisomerization of 1,1′-Binaphthyl Conducted in Liquid Crystal and Solid Phases

Abstract

The atropisomerisation of 1,1′-binaphthyl has been studied through the phase transitions (twisted) nematic → smectic A → solid in a solvent consisting of a mixture of alkylcyanobiphenyls and an alkylcyanoterphenyl. Increases in rates with decreasing temperature and increasing apparent order of the solvent medium are observed. Enthalpy and entropy both decrease in value as the phase order increases. By studying in detail the thermograms of these and related systems, it is shown that phase rejection and consequent phase heterogeneity is an important factor in this anti-Arrhenius behavior.

Key Words:

• Liquid crystals
• phase separation
• kinetics
• atropisomerization
• 1,1′-binaphthyl