Synthesis of new alkyl maleates ammonium derivatives and their uses in emulsion polymerization

The synthesis of several ammonium derivatives of maleic acid diesters are reported. The starting material is the hemiester of maleic acid, easily obtained from ring opening of the maleic anhydride. The hemiester is submitted to functionalization with an aminated compound, followed by quaternarization with the convenient alkylation reagent. Products crystallize easily and yields are generally high. They have been fully characterized by H-1 and C-13 NMR and the CMC have been measured. Some of them have been engaged in emulsion polymerization with styrene or methyl methacrylate. Maleates functionalized with quaternary ammonium salts yield polystyrene particle sizes around 30 nm with a narrow size distribution without adding ally additional emulsifier.