138946-76-6Relevant articles and documents
Study on Differential Scanning Calorimetry (DSC) of 4-(4'-n-Alkoxycinnamoyloxy) Ethoxybenzenes (A) and 4-(4'-n-Alkoxycinnamoyloxy)-n-Propoxybenzenes (B)
Agrawal, Y. K.,Vyas, P. R.
, p. 243 - 250 (2007/10/02)
Two homologous series (A) and (B), with the following structure p-RO-C6H4-CH=CH-CO-O-C6H4-OR'(p) , were synthesized by reacting 4-n-alkoxycinnamoyl chlorides with 4-ethoxyphenol and 4-n-propoxyphenol, respectively.It was envisaged that the esters from esterification of 4-n-alkoxy cinnamic acids with 4-substituted phenols would have relatively lower transition enthalpies than the analogous phenylbenzoates.This is reflected in the mesogenic behaviour of both these series.The solid-mesogenic and mesogenic-isotropic transitions are lowered considerably.Both series exhibit nematic behaviour at short chain lengths and both smectic and nematic phases at longer chain lengths.DSC studies not only confirmed the results observed under polarising microscope but also revealed additional phase transitions in the solid phase.Entropies and enthalpies are also provided.Enthalpy values of structurally similar compounds reveal that the values for these series are comparable.The enthalpies of various types of phase transitions also fall in the range of reported values for these transitions.