Tech Briefs

Description

Historically, the production of isotopically exchanged organic material through catalytic isotope exchange is done by exposing an organic molecule-catalyst mixture in a heated, sealed vessel to D2 gas or D2O liquid. This batch process is inefficient and insufficient for the scalable production of highly deuterated organics as hydrogen isotope exchange is governed by the fundamental equilibria between the isotopologues in the two phases. Another issue is that the high pressure, high temperature environment of the sealed vessel may change the molecular structure of the target molecule. Alternatively, some deuterated organic molecules may be synthesized from deuterated precursors. However, the types of molecules that can be achieved in this manner are constrained by known chemical reaction pathways and the availability of the necessary precursors. Further, this approach is not applicable to detritiation of organics with entrained tritium. Thus, there remains a need to achieve selectively or highly exchanged complex organic molecules in a manner that does not require altering chemical structures.

A continuously purged system is one way to circumvent the equilibrium limitation of isotope exchange reactions. In this case, a pure hydrogen isotope stream (e.g., D2) continuously flows into the reactor and interfaces with the organic or organosilicon molecules and catalysts. The outlet flow carries away both the exchanged and unexchanged hydrogen isotopes, which continuously keeps the equilibrium favorable for isotope exchange. It is important to note that sealed, batch systems conserve deuterium and tritium, while a traditional flow-through system would “waste” a significant amount of these precious resources. Further, in the case of the tritiation and detritiation, the outlet flow would be an environmental health hazard due to the presence of tritium. However, if the flow-through system is coupled with a hydrogen isotope processing system, as in the CECIE process, then the outlet flow can be readily processed to recover the deuterium or tritium, negating these issues. For the detritiation of organic and organosilicons in tritium processing facilities, the catalytic isotope exchange process can be coupled with the existing process infrastructure to manage the tritium effluent. For catalytic deuteration/tritiation, a flexible hydrogen isotope processing system can be coupled with the reactor.