Enhanced Reactivity of Nucleophiles in Polyethylenimines PEIs

To assess the aminolytic effectiveness of the polymer amines, the cleavage reaction of Eq. (2) has been followed. If an amine P-NH2 is used in the aqueous solution, one obtains RCONHP instead of RCOOH. 

With nonacylated polyethylenimines (Table 3.1) the rate constant is increased ca. 4-fold over that of propylamine. This small enhancement may merely be because a greater fraction of the polymer s primary amine groups are in the basic, NH2 state. With these polyethylenimines, as with propylamine, k drops with increasing length of the hydrocarbon chain of the acyl nitrophenyl ester. 

Markedly different trends in the rate constants appear for aminolysis by lauroyl-poly-ethylenimine (containing 10 residue % lauroyl groups). For each nitrophenyl ester the rate is substantially greater with lauroyl-polyethylenimine than with polymer contain- 

Amine p-Nitrophenyl acetate p-Nitrophenyl caproate p-Nitrophenyl laurate 

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