An upper limit to the influence of chiral discrimination on some transport properties of gaseous stereoisomers

Stereospecific interaction between optical isomers is investigated by studying its impact on gas phase transport properties at room temperature. Using differential techniques, both the thermal conductivity and the viscosity of optically pure samples were compared with those of the racemic mixture. Despite the high sensitivity achieved experimentally, no differences were observed. Upper limits in the case of thermal conductivity were found to be δλ/λ ⩽ 3 × 10-6 for 2-butanol and 2-chloro-butane, and ⩽ 3 × 10-5 for fenchone. For the viscosity, δη/η ⩽ 2 × 10-4 for 2-butanol. A theoretical description of the dependence of transport properties on stereoisomeric composition is given.