The mechanism of starch granule reacted with OSA by phase transition catalyst in aqueous medium.

The reactivity of octenyl succinic anhydride (OSA) with starch by phase transition catalyst (PTC) was investigated. The effects of two types (quaternary ammonium salt and non-ionic surfactant) and concentrations of PTC on the degree of substitution (DS) and reaction efficiency (RE) of OS-starch were examined. In aqueous medium, the use of a PTC, polyoxyethylene lauryl ether (AEO) produced derivatives with higher DS than others. The DS of OS-starch reached 0.0195 with 0.1% AEO, significantly higher than that (0.0182) without the use of PTC. As the concentration of AEO increased, the DS of OS-starch did not increase. The structural of AEO was investigated by nuclear magnetic resonance (NMR) spectroscopy. Conductivity measurement and Fourier transform infrared (FT-IR) spectroscopy confirmed that AEO could form complexes with Na(+). The complex of AEO and Na(+) could combine with starch-O(-), it should be possible to improve the transport of anion starch-O(-) to the hydrophobic reagents.