Ionothermal synthesis : a new synthesis methodology using ionic liquids and eutectic mixtures as both solvent and template in zeotype synthesis
Abstract
The aim of this thesis was to research the new synthesis methodology of ionothermal
synthesis, used for the synthesis of zeolite type materials, mainly aluminophosphates.
An ionic liquid or eutectic mixture is to act as both the organic template and the solvent,
hence eliminating the space filling effects in the reaction from the water.
Initial reactions were carried out using the ionic liquid 1-ethyl-3-methylimidazolium
bromide which acted as the solvent and template in the production of four three-dimensional structures and one layered structure. The addition of cobalt into the
aluminophosphate framework was investigated and resulted in three different cobalt-aluminophosphates being synthesised, including one new zeolite framework.
Experiments were carried out into the effect of altering the imidazolium cation alkyl
chain. It appears likely that in the presence of fluoride, some of the imidazolium cations
undergo a metathesis reaction forming 1,3-dimethylimidazolium which acts as a
template in the formation of an aluminophosphate. Preliminary investigations have also
been started into the effects of changing the ionic liquid anion from bromide to
phosphorus hexafluoride and bis((trifluoromethyl)sulfonyl)amide. The use of these
anions resulted in the production of several different one and two-dimensional
structures.
The use of eutectic mixtures as solvent and template was also investigated as a cheaper,
more easily synthesised solvent than the ionic liquids. The results show a new
methodology of eutectic mixtures acting as template delivery agents through the slow,
in situ decomposition of the urea derivative of the eutectic mixture. This synthesis
method resulted in the formation of nine one and two-dimensional aluminophosphates.
Type
Thesis, PhD Doctor of Philosophy
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