SEPARATION OF ISOTOPES. Annual Progress Report
The chemical exchange systems NO-HNO/sub 3/ and NO-N/sub 2/O/sub 3/ as described previously were successful in the preparation of over 99% N/sup 15/ and the exchange of NO with nitric acid solutions appeared promising for the concentration of O/sup 16/. These systems require chemical reflux. Exchangedistillation systems have the desirable feature of not requiring chemical reflux. Several such systems for concentration of N/sup 15/ or O/sup 18/ were considered. They include the following exchange reactions: nitric oxide with nitric oxide complexes of cupric chloride and cupric bromide in nonaqueous solvents; nitric oxide with nitrosonium salt solutions; nitric oxide with nitrosyl bromide; carbon dioxide with non-aqueous solutions of carbamates; and nitrogen dioxide with liquid dinitrogen tetroxide. Of the systems involving nitric oxide, its exchange with complexes of nitric oxide and cupric chloride in methanol solutions was the most promising for the concentration of N/sup 15/. The enrichment factor was found to be 1.017 at --20 deg C. Experiments with exchange-distillation columns showed that the exchange was rapid. Stage heights of 2.2 to 3.0 cm were obtained at interstage flows of 1.0 and 1.3 m moles of nitric oxide per cm/sup 2/-min at temperatures from -- 20 deg to 14 deg C. O/sup 18/ concentrated along with the N/sup 15/, but to a lesser extent. The favorable enrichment factor for the exchange of O/sup 18/ between carbon dioxide and water (1.038 at 25 deg C) made the system an attractive one for the concentration of O/ sup 18/, provided the exchange could be effectively catalyzed. The effect of several catalysts on the rate of the exchange was investigated. Of the substances investigated, mixtures of amines and selenous acid exhibited the most pronounced catalytic effect. The problems concerned with the use of these catalysts in the exchange columns were considered. Preliminary results were also obtained on exchange-distillation systems involving carbon dioxide and carbamate formation with non-aqueous solutions of amines. The reflux reactions for the concentration of O/sup 18/ by the exchange of nitric oxide with nitric acid solutions and the use of the exchange reaction between nitrogen dioxide and liquid dinitrogen tetroxide in a two-temperature system are described. The eIfective separation factor for a particular isotopic species in a multicomponent mixture of isotopes such as occurs in the distillation of nitric oxide or water, is discussed. (auth)
- Research Organization:
- Columbia Univ., New York
- DOE Contract Number:
- AT(30-1)-755
- NSA Number:
- NSA-16-002101
- OSTI ID:
- 4833960
- Report Number(s):
- TID-13776; CU-14-61 AT(30-1)75
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- United States
- Language:
- English
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SEPARATION OF ISOTOPES. Annual Progress Report