Hydrogen isotope exchange between fluoroform (CF₃H) and water. 4. Catalysis by NaOH and anionic resin above 100 °C as an alternative to DMSO addition for rate enhancement

Abstract

Measurement of rate constants for NaOH-catalyzed CF3D/H2O isotopic exchange has been extended from 80 to 140 °C. Corresponding CF3H solubility data were obtained for water and 1.0 mol/L NaOH solution up to 120 °C. Above 120 °C, the NaOH solution provides sufficient catalytic activity to be considered as a simple alternative to the use of aqueous DMSO systems containing NaOH for a CF3H redeuteration process.Tests done with both Ionac A-935 and regular types of anion exchange resin in the hydroxide ion form indicate that these resins, although initially quite effective for deuterium exchange catalysis, lose their reactivity when employed above 100 °C. The thermal instability of this type of supported −OH catalyst makes it unsuitable for use (as a substitute for NaOH) at elevated temperatures in packed towers in a commercial process.

Multiphoton absorption and decomposition studies of chloroform-d induced by a pulsed 13CO2 laser

“…Of these, fluoroform is currently the one most promising (6)(7)(8)(9)(10)(11)(12)(13)(14) and may also be suitable for tritium recovery (1 5-18). However, there are two major obstacles to the use of fluoroform in a heavy water process: ( a ) efficient MPD of fluoroform requires fluences in excess of 20 J/cm2, which, combined with the need to use short pulses (9) (AT .= 1-2 ns) leads to laserinduced damage of windows which complicate the design of the photolysis cell and (b) exchange of fluoroform with water or natural gas is too slow for a practical exchange step without ' AECL Contribution Number 8869 the use of a catalyst ( 1 1).…”