Kinetics of Model Reactions for Interfacial Polymerization

Jeffrey Robertson,Anne Padias,Henry Hall,Trevor Centeno-Hall,Robert Bates

doi:10.3390/polym4010741

Abstract

To model the rates of interfacial polycondensations, the rates of reaction of benzoyl chloride and methyl chloroformate with various aliphatic monoamines in acetonitrile were determined at 25 °C. Buffering with picric acid slowed these extremely fast reactions so the rate constants could be determined from the rate of disappearance of picrate ion. The rates of the amine reactions correlated linearly with their Swain-Scott nucleophilicities.

Highlights

Interfacial polycondensation is an important polymerization technique, recently used for membrane formation [1] and encapsulation [2]
We utilized a novel technique to determine the rate constants in organic solvents: amine picrates were reacted with acid chlorides in acetonitrile solution
The kinetic data resulting from the averages of several runs at varying concentrations are summarized in Table 1 with the amines listed in order of increasing nucleophilicity

Summary

Introduction

Interfacial polycondensation is an important polymerization technique, recently used for membrane formation [1] and encapsulation [2] It involves the extremely rapid reaction of diacid chlorides or bis-chloroformates with diamines. This process has been known for over fifty years [3,4,5], measurement of the rate constants has not yet been reported. We utilized a novel technique to determine the rate constants in organic solvents: amine picrates were reacted with acid chlorides in acetonitrile solution. The reactions were followed by UV, which monitored the disappearance of picrate ion In this way the concentration of free amine is buffered to very low concentrations which allow rate measurements.

Experimental Section

Results and Discussion

Conclusions