摘要: The vapor pressure isotope effects (VPIE) between exp 13 CH sub 2 F sub 2 and exp 12 CH sub 2 F sub 2 and one between exp 12 CD sub 2 F sub 2 have been measured between 150 and 250 exp 0 K. The exp 13 C/ exp 12 C effect is inverse... 展开 The vapor pressure isotope effects (VPIE) between exp 13 CH sub 2 F sub 2 and exp 12 CH sub 2 F sub 2 and one between exp 12 CD sub 2 F sub 2 have been measured between 150 and 250 exp 0 K. The exp 13 C/ exp 12 C effect is inverse, and its magnitudes fall within a narrow difference between the exp 13 C/ exp 12 C-VPIE of methyl fluoride and fluoroform. The (normal) D/H-VPIE, however, shows magnitudes which are significantly higher than the D/H-VPIE's of methyl fluoride and fluoroform. In preparation for VPIE measurements of liquid and solid ammonia, exp 14 NH sub 3 , exp 15 NH sub 3 , and exp 14 ND sub 3 samples have been purified against water, O sub 2 , CH sub 4 , N sub 2 , and CO by using a combination of sodium treatment, distillation, and preparative GC. Impurity levels of the purified specimen are below 5 ppM for all impurities. The exp 15 N fractionation column system based on the NO/N sub 2 O sub 3 exchange, has been successfully operated under pressures up to 3 atm. The single stage separation factor ( alpha ) linearly increases with pressure, from 1.006 at 1 atm to 1.029 at 2.7 atm at 15.5 exp 0 C. The HETP slowly increases with decreasing concentration of +4 nitrogen which catalyzes the exchange reaction. However, the overall separation increases with pressure, from 1.5 at 1 atm to 4.0 at 2.7 atm. The closed-cycle product-reflexer for the Nitrox process, in which Fe exp 2+ /Fe exp 3+ solution in sulfuric acid is circulated between a product refluxer and electrolytic Fe exp 2+ -regeneration cells, has been studied to determine the extent of loss of enriched nitrogen in the refluxing system. The second-order orthogonal approximation for the zero-point energy (ZPE) has been refined, and new approximation parameters have been obtained. (ERA citation 09:002971) 收起