For the pharmaceutical industry, the manufacture of high value pharmaceuticals from natural products, chemical synthetic routes or fermentation processes all require intensive downstream processing steps to produce a pure final product. A small footprint liquid-liquid processing method would help to reduce the capital cost and process development time of this downstream processing. In this thesis, it is hypothesised that continuous liquid-liquid extraction can be achieved using a standard hydrodynamic counter-current chromatography (CCC) instrument by switching the flow of the liquid phases between normal phase and reversed phase intermittently, so separating a feed stream into two eluant flows. A model of the process was derived and tested on three scales of instrument, from the semipreparative to the pilot scale. The method developed, Intermittent Counter-current Extraction (ICcE) was compared to dual-flow counter-current chromatography (DFCCC), the classical method of applying continuous extraction using a counter-current chromatograph. ICcE was found to be advantaged due to the more stable phase volume ratio achievable in the columns and the ability to operate the procedure on standard commercial twin-column CCC instruments which operate at high g-field. The robustness of the ICcE method was successfully demonstrated across a range of phase system polarities and at high throughput (1kg/day on a preparative instrument) with model mixtures of pharmaceutical compounds. The effectiveness of this new processing method was confirmed on three industrially relevant case studies. Firstly a polar extract from natural senna pods to extract important sennosides, secondly an intermediate polarity highly complex active pharmaceutical ingredient waste stream to recover the main active component and thirdly a non-polar natural product extract to recover macrocarpal compounds. In summary, the ICcE method now offers another tool in the range of liquid-liquid separation methods available to the pharmaceutical and other high value industries.

Four potential new monomers were prepared, all of which were structural analogues of BisGMA (2,2-bis(4-(2-hydroxy-3-methacryloxyprop-1-oxy) phenyl)propane). The synthesis of these tetrafunctional dimethacrylate monomers was based on structural modifications of Bis-GMA in the core and the side chain and required a two-step reaction. The first step was propoxylation or ethoxylation of the bisphenols and the second step was the methacrylation of the resulting products. The core structures are designated by Bis-A for isopropylidene and 6F for hexafluoropropyl. The side chain structures were designated on the basis of the pendant side chains in the glycidyl moiety as -OH, -H, and -CH3 from the epichlorohydrin, ethyleneoxide, and propyleneoxide reaction products with the bisphenols, respectively. Bis-GMA was commercially obtained and used as a standard for comparison of the experimental monomers. All the monomers were prepared by the following general procedure of propoxylation or ethoxylation of the biphenols followed by methacrylation. They were characterized by NMR, FTIR, DSC and Cone and Plate Viscometry. All the experimental monomers exhibited lower viscosities and glass transition temperatures than the control, which was attributed to the elimination of the hydrogen bonding. The monomers were photopolymerized in a differential scanning calorimetry modified with an optics assembly (DPA 7; Double Beam Photocalorimetric Accessory) to study the photo-induced crosslinking reactions. The influence of monomer structure, temperature, light intensity, and initiator concentration on the photopolymerization kinetics of ethoxylated and propoxylated dimethacrylates was investigated by isothermal DSC. The DSC curves showed a rapid increase in rate due to the Trommsdorff effect, and then a decline due to the decrease of monomer concentration and the autodeceleration effect. The monomers with lower viscosities and glass transition temperatures exhibited higher conversions of the double bonds. The final extent of conversion increased with curing temperature, light intensity and initiator concentration. The radiation intensity exponent varied from 0.68 (BisGMA) to 0.74 for the ethoxylated 6F system. The initiator exponent were varied from 0.34 (for BisGMA) to 0.44 for the propoxylated BisA system. The ratio of the reaction rate constant (kt/kp) was calculated for PropBisAdm from both steady-state and non steady-state conditions. The effect of dilution on photopolymerization kinetics of BisGMA/triethyleneglycoldimethacrylate (TEGDMA) mixtures was also studied by isothermal photo-DSC. Dilution with TEGDMA significantly reduced the viscosity and glass transition temperatures of the mixtures due to the increase in the flexibility. The extent of polymerization increased with increasing TEGDMA and curing temperature. The calculation of ratio of rate constants (kt/kp) was also determined and the significance was discussed herein. / Master of Science