Applications, thermal microscopy heating

In the p-alkoxyphenyl esters of cyclohexanedicarboxylic acid, the series was prepared and thermally examined in which the alkoxy group was varied from methoxy through hexyloxy The thermal properties and analytical results for this series are listed in Table 1. The first two members of the series have only nematic mesophases, while the propoxy through the hexyloxy have both nematic and smectic phases As the length of the alkyl tail increases, so does the complexity of the transitions There are four distinct solid polymorphs in the pentyloxy and three in the hexyloxy compound The hexyloxy also has three smectic phases as well as the nematic These three transitions were identified as smectic by microscopy, however no attempt was made to assign them to a particular class The heats of two of these transitions were too small to measure with any degree of accuracy and only the temperatures were recorded Solid polymorphism, such as encountered in these compounds where the transitions occur at very close temperatures, prevents the application of the differential scanning calorimetric method for determination of purity ... 

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