MOLECULAR-ORGANIZATION OF REAGENTS IN THE KINETICS AND CATALYSIS OF LIQUID-PHASE REACTIONS .6. PECULIARITIES OF THE TEMPERATURE DEPENDENCESOF THE RATE CONSTANTS FOR THE CATALYTIC REACTIONS OF URETHANE FORMATION

The temperature dependences of the rate constants for the reaction of m-chloro-phenylisocyanate with n-butanol in heptane in the presence of tributyltin acetate and acetic acid as catalysts are investigated, Th e deviations from the Arrhenius equations are related to the parallel reaction routes, whose contributions to the observed rate constant var y with temperature due to the effect of the latter on the equilibrium of the alcohol association. Considerable differences in the behavior o f the temperature dependences of the observed rate constants for the n oncatalytic and catalytic reactions stem from the fact that the latter involves the monomeric alcohol form, which is virtually inactive in t he noncatalytic reaction of urethane formation, but plays a crucial ro le in the catalytic process, forming reactive complexes with the catal yst.