The electronic structures, charge distribution and bond orders in maleic anhydride (MA), hydroxide ion, and α- hydroxysuccinic anhydride carbanion (HOSA^-) have been calculated using an AM1 method. On the basis of the Frontier Orbital Theory and three Bonding Principles, the possibility of reaction of active HOSA^- carbanion on polymerization process of MA by alkali catalyst and the mechanism of anionic polymerization of maleic anhydride were studied. Calculations verify nicely the experimental findings.

Key words: REACTION MECHANISM, MALEIC ANHYDRIDE, POLYMERIZATION, ANION, ELECTRONIC STRUCTURE, HOMOPOLYMER, CHARGE DISTRIBUTION, HYDROXYL COMPOUNDS, CARBON ION, FRONTIER ORBITAL THEORY