Mesogenic alkoxy benzoates with propoxyethyl tail

Propoxyethyl 4-hydroxybenzoate was used to condense several 4-n-alkoxybenzoic acids, resulting in a new mesomorphic homologous series of ester exhibiting mesomorphic behavior at relatively low temperatures. Series In propoxyethyl 4-(4-n-alkoxybenzoyloxy)-benzoates have three no mesogenic members: the n-butoxy member showed only a monotropic nematic phase, the n-pentyloxy derivative showed a monotropic Sm A phase, and the hexyloxy derivatives showed an enantiotropic Sm A mesophase that lasted until the n-hexadecyloxy derivative. Plotting the changeover temperature in Series In in contradiction of the number of carbon atoms in the alkoxy chain demonstrates the typical odd–even consequence. It also indicates a propensity for Smectic-isotropic transitions to rise as the series ascends and smooths out for the higher homologues.