Some Aspects on the Optical Resolution by Preferential Crystallization based on Phase Equilibrium
The relationship of racemic structure to resolution by preferential crystallization was discussed on the ternary phase diagrams of systems containing optical isomers and a solvent. From these discussions, it was concluded that the resolution by this method is applicable only to racemic mixtures, and that racemic compounds and also racemic solid solutions can not be resolved. In addition, we reexamined the resolution of 3, 3-diethyl-5-methyl-2, 4-dioxopiperidine reported to be resolved by this method in spite of the formation of a racemic solid solution, and found it impossible to resolve this compound by preferential crystallization.
Abstract A study was performed to investigate the effects of the application of an atmospheric-pressure plasma jet during polycrystalline diamond (PCD) micro- end-milling. A comparison was made between SiC surfaces after milling, with and without the application of the plasma jet. The plasma jet was found to allow the formation of a high-quality surface with an average roughness ( R a ) of 0.73 nm. The proposed plasma jet is highly effective in improving both the chip formation process, by imparting hydrophilicity to the tool and workpiece surfaces, and removing surface contamination at the tool edge during machining.