The Reaction Rate of Acetic Anhydride and Water

Abstract

The infrared absorption of acetic acid and acetic anhydride has been measured from 1μ to 6.5μ. A number of bands were observed below 5μ which were similar for the two substances, and were attributed to CH bonds. An intense band was found in acetic anhydride at 5.45μ and in acetic acid at 5.75μ. By measuring the intensity of these bands at different times, the reaction velocities of equivalent amounts of anhydride and water were determined. This method offers a new and independent means of determining reaction velocities and related constants. The reaction was approximately unimolecular for any concentration. The reaction constant decreased as the time increased. A different value of the constant was obtained when different concentrations were used. The reaction constant was also determined for three different temperatures. The values of the reaction constant and other constants are tabulated. The error is estimated to be 10 percent.