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Synthesis, Characterisation and Applications of Novel Ionic Liquids.

A series of novel phosphinate-based ionic liquids have been synthesised using various organic phosphorus acids, such as mono-n-octylphosphinic acid (octylPO₂H₂), mono-n-hexylphosphinic acid (hexylPO₂H₂), di-n-octylphosphinic acid ((octyl)₂PO₂H), di-n-hexylphosphinic acid ((hexyl)₂PO₂H) and bis(2,4,4-trimethylpentyl)phosphinic acid ((TMP)₂PO₂H), by reaction with tetrabutylphosphonium hydroxide (Bu₄POH), tetrabutylammonium hydroxide (Bu₄NOH), pyridine (py) and triethylamine (Et₃N). Reactions simply involve neutralizing the organophosphorus acids with bases. The only byproduct, water, and excess amine, py/Et₃N can be easily removed under vacuum (Chapter 2). Some of the physical and chemical properties of these ionic liquids have been characterized by NMR, ES-MS, TGA, UV-Visible spectroscopy etc. The formed tetraalkylphosphonium/tetraalkylammonium phosphinate ionic liquids are viscous, hygroscopic liquids, but are more thermally stable than trialkylammonium and pyridinium analogues. For example, for the most stable ionic liquid, [Bu₄P][(octyl)₂PO₂], its onset temperature of decomposition in thermal gravimetric analysis (TGA) is 358 °C (Chapter 2). One of the applications of these novel phosphinate-based ionic liquids has been investigated. Au(0), Rh(0) and Ir(0) nanoparticles have been prepared in some of these phosphinate-based ionic liquids as a media and (or) reducing agents and have been characterized by SEM, TEM, Zetasizer, UV-Visible spectroscopy and IR spectroscopy. In general, the average particles size of Au(0), and Ir(0) were ca. 25 nm, but some of the particles average size formed was less than 2 nm, such as Rh(0) and Ir(0) nanoparticles formed in [Bu₄P][(octyl)₂PO₂] or [Bu₄P][(TMP)₂PO₂]. Generally, these phosphinate-based ionic liquids are good media to prevent nanoparticle aggregation (Chapter 3).
Type of thesis
Ying, L. (Li). (2006). Synthesis, Characterisation and Applications of Novel Ionic Liquids. (Thesis, Master of Philosophy (MPhil)). The University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/9987
The University of Waikato
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