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Studies of some novel piperazine derived amphiphiles and polymeric materials
Author
Roshan Deen Gulam Rasool
Supervisor
Gan, Leong Huat
Abstract
This thesis describes the study of some novel piperazine derived amphiphiles and polymeric materials.
In the first chapter, the synthesis of a series of some long chain piperazine derivatives, Nalkyl-N'- methyl piperazine and their amphiphilic salts, N-alkyl-N'-ethyl-N'-methyl piperazinium bromide, the related N-alkyl-N,N-dimethyl piperazinium bromide, and the polymerizable counterparts, N-acryloyl-N'-alkyl-N'-methyl piperazinium bromide were described. The products were characterized by 1H and 13C NMR FTIR spectroscopy; and elemental analysis. The NMR data showed unequivocally that the quaternization of Nalkjl-N'-methyl piperazine by the reaction with ethyl bromide, and the quaternization of Nacryloyl-N'-alkyl-N'-methyl piperazine by the reaction with n-alkyl bromide occurred exclusively at the nitrogen atom bearing the methyl group due to the steric hindrance of the substituents.
Critical micelle concentration (c.m.c.) and surfactant properties of the amphiphiles were investigated. Plots of surface tension y against log (concentration) were presented. It was found that yc.m.c. increased progressively with the increase in the alkyl chain length for the three homologous series of amphiphiles, indicating that the piperazine moieties were more available for interaction with water as the chain lengh increased. N-acryloyl-N'-alkyl-N'-methyl piperazinium bromide were polymerized under both micellar and isotropic conditions. The polyelectrolyte behaviour was studied by viscometric method. The polymers prepared under micellar conditions had a higher intrinsic viscosity than the ones prepared under isotropic conditions. This was attributed to the aggregation of the monomers under the micellar environment.
The second chapter describes the synthesis of some polymeric materials of piperazine. N-acryloyl-N'-methyl piperazine (AcrNMP), homopolymer of AcrNMP, crosslinked polymers of AcrNMP with ethyleneglycol dimethacrylate, copolymers of AcrNMP with MMA, N-rnethacryloyl-N'-methyl piperazine, and N,W-diacryloyl piperazine were synthesized. The monomer ratios in the copolymer were analyzed by FTLR spectroscopy. The reactivity ratios of the copolymers of AcrNMPMMA were evaluated both by the Finernan-Ross (F-R) and Kelen-Tudos (K-T) methods. The monomer reactivity ratios were found to be r1(AcrNMP) = 0.552 and r>(MMA) = 1.074. The swelling ratio of the crosslinked polymers decreased with an increase in the percentage of the crosslinker used. This was attributed to the hydrophobic nature of the crosslinker.
In the third chapter, the application of a piperazine based copolymer (AcrNMPmllMA) for the detection of Hg(I1) ions, using anodic stripping voltammetry was presented. A chemically modified electrode (CME), was fabricated by attaching the copolymer film to a glassy carbon electrode. The polymer swelled in aqueous solution, allowing easy access of Hg(I1) ion for binding. The effects of pH of the measurement and deposition solutions, deposition time and the Hg(I1) concentrations were studied. The limit of detection was estimated to be 0.23 μglml.
In the first chapter, the synthesis of a series of some long chain piperazine derivatives, Nalkyl-N'- methyl piperazine and their amphiphilic salts, N-alkyl-N'-ethyl-N'-methyl piperazinium bromide, the related N-alkyl-N,N-dimethyl piperazinium bromide, and the polymerizable counterparts, N-acryloyl-N'-alkyl-N'-methyl piperazinium bromide were described. The products were characterized by 1H and 13C NMR FTIR spectroscopy; and elemental analysis. The NMR data showed unequivocally that the quaternization of Nalkjl-N'-methyl piperazine by the reaction with ethyl bromide, and the quaternization of Nacryloyl-N'-alkyl-N'-methyl piperazine by the reaction with n-alkyl bromide occurred exclusively at the nitrogen atom bearing the methyl group due to the steric hindrance of the substituents.
Critical micelle concentration (c.m.c.) and surfactant properties of the amphiphiles were investigated. Plots of surface tension y against log (concentration) were presented. It was found that yc.m.c. increased progressively with the increase in the alkyl chain length for the three homologous series of amphiphiles, indicating that the piperazine moieties were more available for interaction with water as the chain lengh increased. N-acryloyl-N'-alkyl-N'-methyl piperazinium bromide were polymerized under both micellar and isotropic conditions. The polyelectrolyte behaviour was studied by viscometric method. The polymers prepared under micellar conditions had a higher intrinsic viscosity than the ones prepared under isotropic conditions. This was attributed to the aggregation of the monomers under the micellar environment.
The second chapter describes the synthesis of some polymeric materials of piperazine. N-acryloyl-N'-methyl piperazine (AcrNMP), homopolymer of AcrNMP, crosslinked polymers of AcrNMP with ethyleneglycol dimethacrylate, copolymers of AcrNMP with MMA, N-rnethacryloyl-N'-methyl piperazine, and N,W-diacryloyl piperazine were synthesized. The monomer ratios in the copolymer were analyzed by FTLR spectroscopy. The reactivity ratios of the copolymers of AcrNMPMMA were evaluated both by the Finernan-Ross (F-R) and Kelen-Tudos (K-T) methods. The monomer reactivity ratios were found to be r1(AcrNMP) = 0.552 and r>(MMA) = 1.074. The swelling ratio of the crosslinked polymers decreased with an increase in the percentage of the crosslinker used. This was attributed to the hydrophobic nature of the crosslinker.
In the third chapter, the application of a piperazine based copolymer (AcrNMPmllMA) for the detection of Hg(I1) ions, using anodic stripping voltammetry was presented. A chemically modified electrode (CME), was fabricated by attaching the copolymer film to a glassy carbon electrode. The polymer swelled in aqueous solution, allowing easy access of Hg(I1) ion for binding. The effects of pH of the measurement and deposition solutions, deposition time and the Hg(I1) concentrations were studied. The limit of detection was estimated to be 0.23 μglml.
Date Issued
1996
Call Number
QD506 Ros
Date Submitted
1996