Synthesis of bent-shaped liquid crystals containing nitro as terminal group

Yong, Pui Ling (2007) Synthesis of bent-shaped liquid crystals containing nitro as terminal group. Universiti Malaysia Sabah. (Unpublished)

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Abstract

The main objectives of the study were to synthesized bent-shaped liquid crystal that containing nitro as terminal groups. 4-nitroaniline was used as a stal1ing material for the synthesis. The initial step of the synthesized was diazonium coupling reaction with phenol to obtain 4-(4-nitrophenylazo)phenol. The obtained compound was used for the Williamson ether synthesis to obtain l-bromo-4-( 4-nitrophenylazo )phenoxyhexane. The targeted molecule 1 ,3-bis-[4-( 4-n itrophenylazo )phenoxyhexyloxy ]benzene was prepared by 1-bromo-4-(4-nitrophenylazo)phenoxyhexane was used to resorcinol in the present of potassium carbonate and potassium iodide.The melting point of the final compound was in the range between 75°C to 80°C. From the obtained IR spectra. the functional groups in both compounds, 1-bromo-4-(4-nitrophenylazo)phenoxyhexane and 1,3-bis-[4-(4- nitrophenylazo)phenoxyhexyloxy]benzene were compared. It showed that the synthesized compound had all the functional groups as in the projected molecular structure except a band of hydroxyl group in the 1 ,3-bis-[4-(4-nitrophenylazo) phenoxyhexyloxy] benzene. The mesomorphic properties of the final compound were investigated by differential scanning calorimetry (DSC). It showed the enthalpy changes of transition were 67.7076 Jg�¹ when heating and -44.2609 Jg�¹ when cooling.

Item Type: Academic Exercise
Uncontrolled Keywords: liquid crystal, mesomorphic, differential scanning calorimetry, melting point, IR spectra, diazonium coupling reaction, phenol
Subjects: T Technology > TP Chemical technology
Divisions: SCHOOL > School of Science and Technology
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 04 Apr 2014 08:05
Last Modified: 13 Oct 2017 02:22
URI: http://eprints.ums.edu.my/id/eprint/8691

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