Azulene is a highly colored aromatic molecule consisting of a five-membered ring fused to a seven-membered ring. It is isoelectronic with naphthalene. However, while naphthalene is nonpolar, azulene has a dipole moment of 1.08 D – approximately equal to that of HCl. The properties of azulene might be of advantage in certain chromatography applications. In unpublished work we have observed that azulenes are much more strongly retained on gas chromatography stationary phases relative to other aromatics with the same number of carbons. We postulate that azulene-modified stationary phases would demonstrate a unique mode of retention: polarity without heteroatoms. This paper describes the synthesis of a new polysiloxane material containing trimethylazulene- and naphthalene-based side chains. These materials were synthesized by the hydrosilylation of alkene-functionalized trimethylazulene and naphthalene onto poly(hydromethyl/dimethyl)siloxane. These polymers were coated onto capillary columns and an evaluation of their separation properties was performed. Results show that these stationary phases form good films on the interior of the capillary, and give sharp peaks and good separation. Analysis of the retention properties of the columns indicate the material is relatively nonpolar. We are also investigating other azulene-containing stationary phases and their separation properties.

Investigating the gas chromatography separation properties of azulene- and naphthalene-modified polysiloxanes

253rd National Meeting (2017)

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