| 摘要 |
PURPOSE:To obtain a CO product having a high content of <13>C by allowing energy such as UV light to act on the raw gaseous CO having a low content of <13>C and concentrating the concd. raw gaseous CO by distillation. CONSTITUTION:The raw gaseous CO is irradiated with light, preferably the UV light from a Kr light source, to partially convert the CO to CO2 and C3O2 (photochemical reaction stage). At this time, <13>C is excited more strongly than <12>C, the reaction rate is increased, and the <13>C content of the CO2 and C3O2 is controlled to about 10-20%. The product mixture of the photochemical reaction is separated by condensation into CO2, C2O3 and unreacted CO (separation stage by cooling). The C3O2 is further oxidized to CO2 which is reduced to CO along with the above-mentioned CO2 (oxidation and reduction stage). The <12>C<18>O is converted to <13>C<18>O (isotope-exchange reaction stage). The CO is distilled at low temp. to recover CO having a high content of <13>CO (low temp.. distillation stage). A CO product contg. >= about 99% <13>C is obtained by this method at a low cost. |
