Preparation of liquid crystals using various alkyl chains with nitro group as terminal

Mohd Aliff Iskandar Zulkarnain, (2007) Preparation of liquid crystals using various alkyl chains with nitro group as terminal. Universiti Malaysia Sabah. (Unpublished)

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Abstract

The objective is to synthesize and prepare three Liquid Crystal (LC) compounds with nitro group as tenninal of differs only by their length of alkyl chains. The preparation started with synthesizing 4-(4 nitrophenylazo)phenol. Initially, it starts with the diazotization of p-nitroaniline to prepare the diazonium salt. The diazonium salt obtained then undergoes a coupling reaction with phenol, which produces 4-(4-nitrophenylazo) phenol in an ice bath to keep the whole reaction under 5ºC. The compound is then left crystallized. Later, three final products were obtained via Williamson Synthesis by reacting the 4-(4-nitrophenylazo)phenol with 1-bromohexane, 1-bromodecane, and 1-bromohexadecane - producing the three 4-(4-nitropheny lazophenoxy )hexane, 4-( 4-nitropheny lazophenoxy )decane, and 4-(4-nitrophenylazophenoxy) hexadecane respectfully. They are then purified and recrystallized. A structure molecule and phase analysis are done via FTIR, 'H-NMR spectroscopy and DSC. The functional groups found are identical with the correspond compounds, and so does it's molecular structure. Enthalpies were also obtained but not the mesophase for all LCs.

Item Type: Academic Exercise
Uncontrolled Keywords: Liquid Crystal, length, alkyl chain, diazonium salt, Williamson Synthesis, enthalpies
Subjects: T Technology > TP Chemical technology
Divisions: SCHOOL > School of Science and Technology
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 13 Mar 2014 07:05
Last Modified: 11 Oct 2017 04:54
URI: http://eprints.ums.edu.my/id/eprint/8121

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