10. 8 Kinetics of reactions in solution Extensive reading Levine, p. 573-576, Section 17.15
10.8 Kinetics of reactions in solution Extensive reading: Levine, p. 573-576, Section 17.15
10.8 Kinetics of reactions in solution Brainstorm: What factors will affect the rate of reaction in solution? Does a reaction differs a lot when it occurs in gaseous state or in solution ○ What is your hypothesis?
Brainstorm: What factors will affect the rate of reaction in solution? Does a reaction differs a lot when it occurs in gaseous state or in solution? What is your hypothesis? 10.8 Kinetics of reactions in solution
10.8 Kinetics of reactions in solution (2)Theoretical model-solvent cage SOME REMARKS ABOUT FREE RADICALS AND THE PHOTOCHEMISTRY OF SOLUTIONS BY PROFESSOR J. FRANCK AND DR. E. RABINOWITSCH(Gottingen) Ill. Secondary Recombination and the Temperature- Coefficient. The equilibrium concentration of free atoms or radicals in a solution as compared with a gas, is affected not only by a decreased rate of forma- tion and the possibility of "primary recombination "but also by an increased probability of norm or“ secondary"” recombination, resulting from the fact that every collision of two radicals or atoms in solution is made a"triple "or"multipl ole ) collis ision by the presence the molecules of the solvent. Thus the velocity of normal recombina- tion will in every solution be greater by the factor I03 to Iof than it i in a gas at atmospheric pressure. J. Franck and E Rabinowitch, Trans. Faraday Soc., 1934, 30: 120
(2) Theoretical model—solvent cage 10.8 Kinetics of reactions in solution J. Franck and E. Rabinowitch, Trans. Faraday Soc., 1934, 30: 120
10.8 Kinetics of reactions in solution (2) Theoretical model-solvent cage 1934. J. Franck and E. Rabinowitch established that. once reactant molecules meet in one solvent cage through diffusion (an encounter), they will be trapped in the cage for a relatively long time during which they collide repeatedly with each other, providing more chance to react Solvent cage: capture reactant molecules diffuse Within a solvent cage(for 1-100 ns),two in or out from or to other solvent cages reactant molecules can collide 10 105 times
(2) Theoretical model—solvent cage Solvent cage: capture reactant molecules diffuse in or out from or to other solvent cages. 1934, J. Franck and E. Rabinowitch established that, once reactant molecules meet in one solvent cage through diffusion (an encounter), they will be trapped in the cage for a relatively long time during which they collide repeatedly with each other, providing more chance to react. Within a solvent cage (for 1~100 ns), two reactant molecules can collide 10 ~105 times. 10.8 Kinetics of reactions in solution
10.8 Kinetics of reactions in solution (2)Theoretical model OOoOOooo P8900 A+B→{AB}→P fAB term represents the caged reactants including the encounter pair and the activated complex 10-12 10-10 s collides for 10 105 times diff reaction control Edit> ere diffusion control
A + B → {AB} → P {AB} term represents the caged reactants including the encounter pair and the activated complex. 10-12 ~ 10-10 s, collides for 10 ~ 105 times. Ere > Ediff. Reaction control. Ediff. > Ere, diffusion control. (2) Theoretical model 10.8 Kinetics of reactions in solution