Evaporative effects, filter media

In a relatively new process for production and fractionation of fine particles by the use of compressible media - the PGSS process (Particles from Gas-Saturated Solutions) - the compressible medium is solubilized in the substance which has to be micronized [58-61]. Then the gas-containing solution is rapidly expanded in an expansion unit (e.g., a nozzle) and the gas is evaporated. Owing to the Joule-Thomson effect and/or the evaporation and the volume-expansion of the gas, the solution cools down below the solidification temperature of the solute, and fine particles are formed. The solute is separated and fractionated from the gas stream by a cyclone and electro-filter. The PGSS process was tested in the pilot- and technical size on various classes of substances (polymers, resins, waxes, surface-active components, and pharmaceuticals). The powders produced show narrow particle-size distributions, and have improved properties compared to the conventional produced powders. 

The oil described above was utilized directly in the condensation reaction with the epichlorohydrin. A mixture of 0.1 mole of methyl 3-(4-hydroxyphenyl)propionate, 0.2 mole potassium carbonate and 0.4 mole epichlorohydrin in 250 mL acetone was heated to reflux for 24 hours. The reaction medium was then filtered and evaporated. The residue was taken up in 100 mL toluene and washed with 100 mL 1.0 N NaOH and 100 mL water (2 times). The toluene phase was then dried over magnesium sulfate and evaporated to provide the crude product as an oil. Purification was effected by vacuum distillation (156°C/0.4 mm) and provided methyl 3-[4-(2,3-epoxypropoxy)phenyl]propionate. The NMR and IR spectra and elemental analysis data were consistent with the assigned structure. 

Freeman and Morrison (1949) have given a detailed procedure for the production of this antibiotic from T. roseum F227. The medium contained 50g of glucose, 2 g of ammonium tartrate, 0.5 g of magnesium sulfate, 1 g of potassium hydrogen phosphate, 0.5 g of potassium chloride, 0.01 g of ferrous sulfate, 10 ml of corn steep liquor, and sufficient water to make 1000 ml of solution. After the pH was adjusted to 5, the culture was allowed to stand for 28 days at 25 , filtered, the filtrate extracted with chloroform, and the chloroform evaporated. Final purification was effected by chromatography on alumina, and gave about 36 mg of trichothecin (I) per 1 of culture filtrate. 

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