Copolymerization of maleic anhydride and norbornene catalyzed by Fe(acac)3-Al(i-Bu)3-CCl4

The characteristics and product structure of alternating copolymerization of maleic anhydride (MA) with norbornene (NBE) catalyzed by Fe(acac)(3)-Al(i-Bu)(3)-CCl4 were studied. The copolymerization can be realized in solvents such as aromatic hydrocarbon, alkane and 1,4-dioxane, and the copolymer yield is the highest in 1, 4-dioxane. When the reaction was carried out in I, 4-dioxane for 12 h under nitrogen atmosphere, the copolymer yield was 85.4%. The copolymer yield increases as temperature and MA/Fe molar ratio increase, and it also increases with increasing Al/Fe molar ratio when the Al/Fe molar ratio is less than 14, but it decreases when the Al/Fe molar ratio is more than 14. The third composition Of CCl4 exerts a great influence on the copolymerization. The best conditions are n (MA)/n (Fe) = 90 similar to 150, n (Al) 177 (Fe) = 14, 17 (CCl4) In (Fe) = 20, n (MA)/n (NBE) = 1 and theta = 70 degrees C. The copolymer structure is characterized by IR, NMR and elemental analysis. The copolymer is a product of high alternation, and the content of MA and NBE are 52.2% and 47.8%, respectively, when n (MA)/n (NBE) = 1. The copolymer molecular weight and its distribution were studied by gel permeation chromatography. The molecular weight distribution is narrow. The kinetic studies indicate that the reaction rate of copolymerization is first order with respect to the monomer concentration. The apparent activation energy of the copolymerization is 74.3 kJ/mol. The copolymerization reaction follows the coordinate mechanism.