CHLORINATION OF N-METHYLACETAMIDE - A KINETIC-STUDY

In the pH range 4.3-13, the reaction between N-methylacetamide (NMA) and sodium hypochlorite in dilute aqueous solution to give N-chloro-N-methylacetamide (CINMA) was found to be far slower than analogous reactions affording N-chloramines or N-chloroamino acids. The rate expression for chlorination was first-order each in [NMA] and [Cl-tot] (the total concentration of chlorinating species). A rate constant calculated for chlorination by each chlorinating species indicated that the order of increasing reactivity was HClO < ClO- < Ch < CH3COOCl (formed in the presence of acetic/acetate buffer). At pH > 7 the reaction rate was unaffected by variations in [Cl-] or pH, but under acidic conditions the rate increased with [Cl-] and decreasing pH. Regardless of pH, the reaction rate was not affected by changes in ionic strength. The influence of temperature on the reaction rate was also studied which allowed calculation of thermodynamic activation parameters for the N-chlorination reaction. (C) 1995 John Wiley & Sons, Inc.