The separation of stable isotopes of carbon

Separation of Carbon Isotopes in Methane with Nanoporous Materials

“…Naturally occurring carbon consists of two stable isotopes, 12 C (98.89%) and 13 C (1.11%), and a minuscule amount of radioactive carbon 14 C (e.g., 1 part per trillion in the atmosphere). Among different molecular forms of carbon isotopes, labeled methane isotopes 13 CH 4 and 14 CH 4 are widely used in organic and analytical chemistry as a powerful agent to detect trace compounds in various chemical and biochemical systems. − Highly specific radioactivity is a prerequisite for applications such as medical diagnosis or in vivo detection of receptor bindings. ,, …”

“…The isotopic effect on carbon-substituted methanes 13 CH 4 , 14 CH 4 , and 12 CH 4 is even more diminutive in comparison with that introduced by isotopic hydrogen substitutions. Especially, the molar volumes of hydrocarbon compounds with peripheral deuterium atoms are substantially smaller than those with skeletal 13 C or 14 C atoms of the same molecular weight. ,, Conventional methods for isotopic separation are mostly based on macroscopic processes that utilize small differences in the thermodynamic or transport properties of bulk systems. ,− Whereas processes such as thermal diffusion, gas–liquid chromatography, or cryogenic distillation have been well-established for industrial production of carbon isotopes, these traditional techniques have extremely low overall separation efficiency and often entail intensive energy consumption and high operation cost. ,,, Relatively inexpensive methods such as chemical isotope exchange are not suitable for industrial-scale applications due to extra energy and material costs affiliated with the recovery of the isotopic products. − Despite its superior separation efficiency, the laser-induced plasma method cannot be scaled up to industrial operations because of high cost and technical difficulties related to the conversion of the direct chemical products to those widely used isotopic carbon compounds …”

“…1−7 Highly specific radioactivity is a prerequisite for applications such as medical diagnosis or in vivo detection of receptor bindings. 5,8,9 Isotopic methanes have virtually identical molecular characteristics and chemical properties. The isotopic effect on carbon-substituted methanes 13 CH 4 , 14 CH 4 , and 12 CH 4 is even more diminutive in comparison with that introduced by isotopic hydrogen substitutions.…”

“…8,12−17 Whereas processes such as thermal diffusion, gas−liquid chromatography, or cryogenic distillation have been wellestablished for industrial production of carbon isotopes, these traditional techniques have extremely low overall separation efficiency and often entail intensive energy consumption and high operation cost. 5,9,18,19 Relatively inexpensive methods such as chemical isotope exchange are not suitable for industrialscale applications due to extra energy and material costs affiliated with the recovery of the isotopic products. 20−22 Despite its superior separation efficiency, the laser-induced plasma method cannot be scaled up to industrial operations because of high cost and technical difficulties related to the conversion of the direct chemical products to those widely used isotopic carbon compounds.…”

Fractionation of Isotopic Methanes with Metal–Organic Frameworks

“…Recent years have witnessed rising interest in separation and purification of radioactive isotopes of different elements for biomedical and analytical applications. For example, high-purity 13 C isotope can be used as a tracer in chemical and biological analysis, early diagnosis of human diseases, and determining chemical reaction mechanisms. − Besides, the increasing energy demand leads to construction of more nuclear power plants and, subsequently, generation of more nuclear waste . Isotope separation is often a prerequisite to store and post-treat radioactive nuclear materials.…”