synthesis of new liquid crystalline diglycidyl ethers合成新的液体水晶缩水甘油醚.pdfVIP

Molecules 2012, 17, 645-656; doi:10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Article Synthesis of New Liquid Crystalline Diglycidyl Ethers Issam Ahmed Mohammed * and Rashidah Mohamed Hamidi School of Industrial Technology, University Sains Malaysia, Penang 11800, Malaysia * Author to whom correspondence should be addressed; E-Mail: issam@usm.my; Fax: +604-6575-854. Received: 3 November 2011; in revised form: 13 December 2011 / Accepted: 17 December 2011 / Published: 10 January 2012 Abstract: The phenolic Schiff bases I–VI were synthesized by condensation reactions between various diamines, namely o-dianisidine, o-tolidine and ethylenediamine with vanillin or p -hydroxybenzaldehyde and subsequent reactions between these phenolic Schiff bases and epichlorohydrin to produce new diglycidyl ethers Ia–VIa. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). All the diglycidyl ethers prepared exhibit nematic mesophases, except for Va and VIa, which did not show any transition mesophases, but simply flow to liquids. Keywords: synthesis; diglycidyl ether; schiff base; liquid crystal 1. Introduction Diglycidyl ether can be differentiated from other organic