Radical kinetics in sub- and supercritical carbon dioxide: thermodynamic rate tuning

Abstract

We report rate constants for muonium addition to 1,1-difluoroethylene (vinylidene fluoride) in CO2 at 290-530 K, 40-360 bar, and 0.05-0.90 g cm(-3). Rate constants are mapped against their thermodynamic conditions, demonstrating the kinetic tuning ability of the solvent. The reaction exhibits critical slowing near conditions of maximum solvent isothermal compressibility, where activation volumes of unprecedentedly large magnitudes on the order of ±10(6) cm(3) mol(-1) are observed. Such values are suggestive of pressure being a significant parameter for tuning fluorolkene reactivity.

A first principles approach to the electronic properties of liquid and supercritical CO2

“…Moreover, scCO 2 is a reference green solvent with a wide spectrum of technological applications which are mainly related to its ability to induce significant and controlled physical-chemical modifications on solvated species. Some examples are the tuning of chemical kinetics at supercritical conditions 5,7 and the dynamics of macromolecules and polymeric chains 8 in scCO 2 . Recent researches also emphasize the interest in the combination of subcritical and supercritical CO 2 with ionic liquids 6 which may lead to the design of sophisticated multiphasic reaction environments.…”

Prediction of rate constants of important chemical reactions in water radiation chemistry in sub and supercritical water – non-equilibrium reactions

“…Many properties of water depend on temperature and density, and this can significantly change the rate constants of reactions. 10,11,13,15,[67][68][69][70][71][72][73][74][75][76][77][78][79][80] These include the efficiency factor (cage effect), 7 the diffusion rate of different species, and the dielectric constant that influences the reactions of charged species. In this work, we considered all these aspects.…”

“…Additional correction to critical fluctuation is needed in order to more accurately model the behavior of the reactions at conditions close to maximum compressibility. 19,67,68,72 Also, influences of pH on rate constants for each reaction need to be considered. For example, D r a f t Figure 12 The rate constants of R17 at different pressures.…”

“…The change of those properties influence reaction kinetics. 11,65,67 However, away from the critical point, liquid…”

Selective Free Radical Reactions using Supercritical Carbon Dioxide

“…This method allows for a direct measurement of Mu rate constants, eliminating the need to make approximations or assumptions required in traditional product analysis methods. Full details of our method and set up may be found in the Supporting Information and in our previous work. − Rate coefficients were determined for a wide range of temperatures, pressures, and densities. All studied samples were oxygen-free.…”