The effect of a promoter on the acidic and catalytic properties of aluminum oxide in the reaction of acetic acid ammonolysis has been studied. It has been shown that the promotion of gamma-Al2O3 with phosphorus-oxygen compounds results in a change in the porous structure, an increase in the concentration of acid sites, and site strength redistribution, thereby enhancing the activity and selectivity of the catalyst. The change in the acid properties of gamma-Al2O3 surface has a significant effect on the second stage of the process, the dehydration of acetamide.