PRESSURE EFFECT AND MECHANISM IN ACID CATALYSIS: VIII. HYDROLYSIS OF ACETAMIDE AND BENZAMIDE

The effect of pressures up to 3 kbar on the rate of the acid-catalyzed hydrolysis of acetamide and benzamide in both dilute and concentrated perchloric acid has been measured. The volumes of activation in dilute acid are consistent with a transition state that is not highly polar. It follows from this that if the attacking water molecule adds to the amidium ion then the reactive amidium ion is the O-protonated form, and if the attacking water molecule substitutes then the reactive amidium ion is the N-protonated form.The volume of activation for acetamide in concentrated acid provides no additional information about the mechanism. That for benzamide in concentrated acid is tentatively interpreted as favoring the O-protonated benzamidium ion as the reactive ion.

[1]  R. Brown,et al.  THE CHEMISTRY OF ETHYLENE OXIDE: VI. THE ACID-CATALYZED REACTION OF ETHYLENE OXIDE WITH ETHANOL–WATER MIXTURES , 1960 .

[2]  J. T. Edward,et al.  APPLICATION OF THE HAMMETT EQUATION TO THE HYDROLYSIS OF SUBSTITUTED BENZAMIDES , 1960 .

[3]  C. Franconi,et al.  Protonation of Amides1 , 1960 .

[4]  J. Koskikallio,et al.  PRESSURE EFFECT AND MECHANISM IN ACID CATALYSIS: IV. THE HYDROLYSIS OF DIETHYL ETHER , 1959 .

[5]  J. Koskikallio,et al.  Pressure effect and mechanism in acid catalysis. Part 3.—Hydrolysis of epoxides , 1959 .

[6]  E. Whalley.  Pressure effect and mechanism in acid catalysis. Part 1 , 1959 .

[7]  C. Niemann,et al.  The Mode of Protonation of Amides , 1958 .

[8]  K. Laidler,et al.  The influence of the solvent on reaction rates , 1956 .

[9]  A. Mele,et al.  Basicity of the Amide Bond1,2 , 1955 .

[10]  L. S. Harrow.  Organic Syntheses, Collective , 1955 .

[11]  M. L. Bender,et al.  Intermediates in the Reactions of Carboxylic Acid Derivatives. IV. The Hydrolysis of Benzamide1-3 , 1955 .

[12]  M. L. Bender,et al.  OXYGEN EXCHANGE DURING THE ACIDIC AND BASIC HYDROLYSES OF AMIDES AND THE ENZYMATIC HYDROLYSIS OF ESTERS1 , 1954 .

[13]  Sc Lim,et al.  The volume change on ionizatin of weak electrolytes , 1954 .

[14]  H. J. Lucas,et al.  Measurement of the Basic Strength of Weak Bases in Glacial Acetic Acid1 , 1951 .

[15]  K. Laidler,et al.  Substituent Effects in the Acid and Base Hydrolyses of Aromatic Amides1 , 1951 .

[16]  S. Brinkley,et al.  Calculation of the Effect of Pressure upon Ionic Equilibria in Pure Water and in Salt Solutions. , 1941 .

[17]  N. F. Hall,et al.  THE STRENGTH OF ORGANIC BASES IN GLACIAL ACETIC ACID SOLUTION1 , 1930 .

[18]  B. Oser,et al.  PRACTICAL PHYSIOLOGICAL CHEMISTRY , 1916 .