Cai Li
2009
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Journal
Journal of Beijing University of Chemical Technology
Abstract
8-[4′-propoxy(1,1-biphenyl)-yloxy]-octanoic acid has been synthesized in two steps from 4,4′-dihydroxybiphenyl and the factors influencing the yield studied. The optimal reaction conditions were found to be as follows: in the first step,with a molar ratio n(4,4′-dihydroxybiphenyl)∶n(1-bromopropane)∶n(alkali) of 1∶1.2∶1,and the weight of potassium iodide being 4.5% of that of 4,4′-dihydroxybiphenyl,under reflux for 8 hours,4-propoxy-4′-hydroxybiphenyl was obtained;in the second step,with a molar ratio n(potassium carbonate)∶n(8-bromooctanoic acid ethyl ester)∶n (4-propoxy-4′-hydroxy)biphenyl of 2∶1.5∶1,and with the dosage of phase transfer agent (tetrabutylammonium bromide) being 10% of that of 4-propoxy-4′-hydroxybiphenyl,refluxing for 24 hours,followed by hydrolysis in methanol,afforded 8-[4′-propoxy (1,1-biphenyl)-yloxy]-octanoic acid in a yield of 40% with a purity of 94.9%. The chemical structure of 8-[4′-propoxy (1,1-biphenyl)-yloxy]-octanoic acid was confirmed by FTIR,and 1H and 13C NMR spectroscopy. The phase transition and liquid crystalline behavior of 8-[4′-propoxy (1,1-biphenyl)-yloxy]-octanoic acid were characterized by differential scanning calorimetry (DSC) and polarizing microscopy (POM). The experimental results indicated that 8-[4′-propoxy (1,1-biphenyl)-yloxy]-octanoic acid is a thermotropic liquid crystal.