Continuous flow homogeneous catalysis using ionic liquid/supercritical fluid biphasic systems
Abstract
Ionic liquid/scCO₂ biphasic systems have been studied as a possible solution to
the main problems concerning homogeneous catalysis reactions such as, the
product/catalyst separation, the catalyst retention in the reaction medium and the
use of organic solvents. The hydroformylation of long chain alkenes (1-octene)
has been carried out as a continuous flow reaction using [OctMIM]Tf₂N (OctMIM
= 1-octyl-3-methylimidazolium, Tf = CF₃SO₂) as the reaction solvent and scCO₂as the mobile phase to extract the products. The performance of the rhodium
complexes formed with the ionic ligands [PentMIM][TPPTS] (1-pentyl-3-
methylimidazolium tri(m-sulfonyl)triphenylphosphine) and [OctMIM][TPPTS]
(1-octyl-3- methylimidazolium tri(m-sulfonyl)triphenylphosphine) is described
under different sets of experimental conditions.
Continuous flow hydroformylation of 1-octene was also carried out using a SILP
(Supported Ionic Liquid Phase) catalyst formed with the TPPTS-based ionic
ligands named above. The SILP system described in this work has the peculiarity
of introducing the “without gases” approach: syn gas was synthesised in situ by
the decomposition of formaldehyde.
The performance of both systems is compared in the end.
The extension of the continuous flow ionic liquid/scCO₂ biphasic system is shown
with the optimisation of the silver-catalysed heterocyclisation of furans. A
comparison is carried out with a previously developed and optimised continuous
flow heterogeneous system.
Type
Thesis, PhD Doctor of Philosophy
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