Amidification of poly(styrene-co-maleic anhydride) with amines in tetrahydrofuran solution: A kinetic study
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- Hu, G.H. & Lindt, J.T. Polymer Bulletin (1992) 29: 357. doi:10.1007/BF00944831
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The kinetics of the reaction between a styrene-maleic anhydride copolymer (SMA) and amines was investigated in tetrahydrofuran solution between 0°C and 40°C. This reaction converts the maleic anhydride (MA) into the corresponding amide-acid, while the consecutive reaction of the generated acid with amine forming a diamide or transformation of the acid-amide into the imide was not observed. The amine reactivity follows the order: 1-octylamine> >1-methyl hexylamine> >1,1-dimethyl propylamine or dibutylamine, demonstrating that the amine reactivity depends, to a large extent, upon its steric hindrance. This reaction is reversible as shown by IR at high temperatures, but the reverse reaction was undetectable between 0 and 40°C. The overall reaction involves spontaneous and autocatalytic reactions, and the overall reaction rate can be written as:-d[MA]/dt=k0[MA][-NH2]+k1[MA][-NH0]2. In the case of 1-octylamine below 0.02 M, the spontaneous reaction dominates (i.e, k0> >k1[-NH2]).