Technological parameters of dimeric ionene-type ionic liquids based on tetrahydro-1,4-oxazine

Abstract

Experimental studies confirmed that introduction of allyl and hydroxyethyl groups, a benzyl fragment, and alkylaromatic radicals into the cationic center of dimeric ionene-type ionic liquids leads to a high ionic conductivity of 10–1 S cm–1 at −1230C. The synthesized dimeric ionic liquids were found to be thermally stable in the range 107–2060C. The presence of –O–CH(CH3)–CH2– groups in the radical adjacent to the quaternized nitrogen atom was shown to enhance thermal stability. Studies of how the nature of the radical near the ionic center affects melting behavior established that the melting point of the dimeric ionene-type ionic liquids increases with an increasing number of –O–CH(CH3)–CH2– units in the radical. In particular, correlations between temperature, chemical structure of the tetrahydro-1,4-oxazine-based dimeric ionic liquids, and their ionic conductivity were established; correlation equations are provided and their chemical basis is discussed. These findings support the proposed mechanism of property formation and demonstrate the practical relevance of the developed compounds.