Notes
In the thesis supercritical fluids and high pressure separation processes were examined. According to literature review the most researches apply to supercritical fluid extraction and isolation of bioactive compound from plant material. Supercritical fluids are in the most cases compressible media, gasses at ambient temperature, therefore products without residues of toxic organic solvents are obtained. Consumption of energy and environment imprint is significantly lower, which greatly contribute to sustainable development. Supercritical extraction isolates variety of compounds from plant material. In order to separate these compounds from each other various chromatographic techniques, such as liquid chromatography, gas chromatography and supercritical fluid chromatography have been applied in the past. Supercritical fluid chromatography is relatively new technique, which was well developed in last decade. In the thesis, supercritical fluid chromatography has been investigated in analytical scale for two test compounds caffeine and theophylline, in order to determine the influence of the process parameters on the chromatographic parameters. Obtained results were used for scale up onto the preparative and production scale, which apparatus is one of the bigger worldwide. Influences of the pressure, temperature, type and concentration of the modifier, and type of the stationary phases have been studied. In supercritical fluid chromatography CO2 is the most frequently solvent used as the mobile phase. If polar compounds are separated, polar modifier, such as methanol, ethanol acetonitrile, iso-propanol etc., are added to the CO2. Chromatographic parameters are the most significantly influenced, when modifier concentration is increased. Pressure and temperature are less significant factor for separation, however it is more important as in liquid chromatography. Afterwards, experiments on analytical scale were conducted, investigations on operating the pilot apparatus were preformed. Regarding on results of the separation on the analytical scale apparatus and regarding on constrains of the equipment, range of process conditions have been determined for test compounds. Several experiments were conducted on pilot preparative scale apparatus at given process conditions. Even though, separation was achieved on analytical scale, such separation was not possible on pilot preparative scale apparatus at similar process conditions. Additionally, several experiments were conducted on the pilot apparatus. With altering the process conditions successful separation has been achieved. However chromatographic signals, which belong to detected compounds, were overlaying. Even though, fractionation was possible. Regarding on obtained results, this method could be applied for separation of real system, such as plant material extracts.