Conversion of Contaminated Post-Consumer Polyethylene Terephthalate into a Thermoset Alkyd Coating Using Biosourced Monomers.

The synthesis of a high-performance oxidative cross-linked thermoset alkyd coating is described that utilizes a novel recycling strategy from contaminated postconsumer waste polyethylene terephthalate (wPET). A single-stage "depolymerization-repolymerization" process has been developed that allows the exploitation of a waste stream from a commercial PET recycling process with 95% efficiency, which, when copolymerized with glycerol and tall oil fatty acid, delivers a sustainable fatty acid-functional polyester suitable for use in thermoset alkyd coatings. Physical drying challenges have been tackled via the development of a convergent polymer formulation strategy from a single source of wPET and the formulation of the resulting fatty acid-functional polymers with commercial alkyd driers, delivering a thermoset alkyd coating suitable for industrial applications.

Investigation of the acid/base behaviour of the opium alkaloid thebaine in LC-ESI-MS mobile phase by NMR spectroscopy.

As part of a research programme to establish an analytical method for the simultaneous detection of the five major opium alkaloids in poppy seeds by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) it was discovered that the inclusion of thebaine produced two peaks for the same compound. This was in contrast to the effective simultaneous detection, by LC-ESI-MS, of morphine, codeine, papaverine and noscapine. The presence of these two peaks for thebaine was investigated using nuclear magnetic resonance spectroscopy with deuterated solvents to emulate the mobile phase conditions experienced. It was found that the presence of 80%, or higher ratios of, water caused two epimeric forms of thebaine to be formed; this explained the presence of two peaks on the chromatogram. In contrast, when a lower water content was used with 1% acetic acid, one stable form of thebaine could be analysed and resulted in a single peak visible in the subsequent chromatography.

An investigation of nitrile transforming enzymes in the chemo-enzymatic synthesis of the taxol sidechain.

Paclitaxel (taxol) is an antimicrotubule agent widely used in the treatment of cancer. Taxol is prepared in a semisynthetic route by coupling the N-benzoyl-(2R,3S)-3-phenylisoserine sidechain to the baccatin III core structure. Precursors of the taxol sidechain have previously been prepared in chemoenzymatic approaches using acylases, lipases, and reductases, mostly featuring the enantioselective, enzymatic step early in the reaction pathway. Here, nitrile hydrolysing enzymes, namely nitrile hydratases and nitrilases, are investigated for the enzymatic hydrolysis of two different sidechain precursors. Both sidechain precursors, an openchain α-hydroxy-ß-amino nitrile and a cyanodihydrooxazole, are suitable for coupling to baccatin III directly after the enzymatic step. An extensive set of nitrilases and nitrile hydratases was screened towards their activity and selectivity in the hydrolysis of two taxol sidechain precursors and their epimers. A number of nitrilases and nitrile hydratases converted both sidechain precursors and their epimers.

A high-throughput screening method for determining the substrate scope of nitrilases.

Nitrile compounds are intermediates in the synthesis of pharmaceuticals such as atorvastatin. We have developed a chromogenic reagent to screen for nitrilase activity as an alternative to Nessler's reagent. It produces a semi-quantifiable blue colour and hydrolysis of 38 nitrile substrates by 23 nitrilases as cell-free extracts has been shown.