It is possible to predict the kinetics of a reaction by using temperature versus time data under adiabatic conditions. This method was used for the cytidine/acetic anhydride reaction using a RC1 Mettler Reaction Calorimeter.
The authenticity of the experimental adiabatic system was verified by determining the kinetic parameters of a known reaction (hydrolysis of acetic anhydride) and comparing them to literature values.
For example, the average experimental activation energy, heat of reaction, and ln k0 values for the hydrolysis of acetic anhydride were 11.2 ±.5 kcal/gmole, -14.4 ± .2 kcal/gmole, and 12.74 ± .94 sec-1, respectfully, while the average literature values were 12.0 ± 2.4 kcal/gmole, -14.3 ± .3 kcal/qmole, and 11.56 ± 1.47 sec-1, respectfully. The reaction was first order.
The cytidine/acetic anhydride reaction (unknown system) was subjected to the same adiabatic analysis and the average experimental activation energy, heat of reaction, and ln k0 values were 13.3 ± .2 kcal/gmole, -10.5 ± .1 kcal/gmole, and 15.68 ± .34 L/(gmole sec), respectfully.
To further verify the results for the unknown system,three isothernal runs were executed and sanples were analyzed for concentration by High Pressure Liquid Chronatography (HPLC). The concentration-time data were analyzed and an Arrhenius Plot was constructed yielding an activation energy of 13.2 kcal/ginole and a ln k0 value of 15.14 L/(gTnole sec). The reaction was second order.
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