99163-23-2Relevant academic research and scientific papers
Mesogenic Properties as an Analytical Tool for the Pyrolytic Transformation of Substituted Aryl Aldehyde Semicarbazones to Corresponding Benzalazines
Chudgar, N. K.,Shah, S. N.,Vora, R. A.
, p. 237 - 242 (2007/10/02)
The evaluation of semicarbazones for the mesogenic properties revealed that it undergoes transformation to azine at elevated temperatures.The transformation products were identified by modern tools.The diazines of 4-n-alkoxy benzaldehydes are reported to be mesogenic.It was planned to use mesomorphism as a tool for analysis.We had established that transformation of a semicarbazone of aldehyde gives diazine.With this in view fourteen 4-n-alkoxybenzaldehyde semicarbazones were synthesized and heated at 260 deg C in an oil bath.The pyrolized products were purified and evaluated for their mesogenic properties.The mesogenic properties of pyrolized products exactly tally with the diazines reported by Shaw and Brown.A few diazines which were not reported are also obtained in present study and are characterized.They also exhibit mesomorphism.The study indicates that if the transformation products can be designed which are conducive to mesomorphism, the mesogenic properties can be the tool to understand it and identify the products.The calorimetric study is carried out and enthalpy values are obtained to understand thermodynamic behavior.
Mesomorphic Properties of the 4,4'-Di(n) Alkoxybenzalazines
Bennur, S. C.,Gault, J. D.,Kroin, T.,Ouriques, G. R.,Taylor, T. R.
, p. 267 - 276 (2007/10/02)
We have reinvestigated the mesomorphic properties of the 4,4'-Di(n) alkoxybenzalazines, first reported by Shaw and Brown.Thirteen members of the series were prepared with the number (n) of carbon atoms varying from 1 to 16.A Nematic phase was always observed except for n >/= 13; a monotropic smectic phase was observed for n = 5, 6 and another smectic phase for n >/= 10.The compounds were examined with a polarizing microscope and heats of transition determined using a DSC-2 calorimeter.Our results differ from those of Shaw and Brown as they did not observe the monotropic smectic phase for n = 5, 6.They also cite a smectic phase for n = 7, 8, 9, 10 whereas we observe a smectic phase only for n >/= 10 (n = 9, was not synthesized by us).The temperature given by Shaw and Brown for the crystal-smectic transitions for n = 7, 8, 9, 10 we identify as the temperatures of crystal-crystal transitions.Of these only n = 10 has a smectic phase and the transition temperature is considerably higher than that given by Shaw and Brown.
