Unraveling the origins of catalyst degradation in non-heme iron-based alkane oxidation.

A series of potentially tetradentate and pentadentate ligands modelled on BPMEN has been prepared and their iron(II) bis(triflate) complexes have been isolated and characterised by spectroscopic and crystallographic techniques (BPMEN = N,N'-bis(pyridylmethyl)ethylenediamine). Changes to the BPMEN ligand have invariably led to complexes with different coordination modes or geometries and with inferior catalytic efficiencies for the oxidation of cyclohexane with H2O2. The reaction of an iron(II) complex containing a pentadentate BPMEN-type ligand with O2 has resulted in ligand degradation via oxidative N-dealkylation and the isolation of a bis(hydroxo)-bridged dinuclear iron(III) complex with a picolinate-type ligand.

Comprehensive monitoring of a biphasic switchable solvent synthesis.

Biphasic reactions were investigated in a specially designed high pressure set-up that allows simultaneous fibre-optic ATR IR and ATR UV-Vis measurements in both phases. The scope of quantitative spectroscopic measurements is tested on the absorption of CO(2) in hexanol and a biphasic switchable solvent synthesis. For both systems, all substances including dissolved and gaseous CO(2) can be quantified and a constant total mass balance over all phases can be achieved for every component in the reaction system. This confirms that the quantification methods are applicable and the reactor can be applied to gain further insight into the microkinetics and transport phenomena of multiphase reactions.