Synthesis and Styrene Copolymerization of Novel Halogen, Alkoxy, and Alkyl Ring-Disubstituted Isopropyl 2-Cyano-3-Phenyl-2-Propenoates

Novel trisubstituted ethylenes, ring-disubstituted isopropyl 2-cyano-3-phenyl-2-propenoates, RPhCH=C(CN)CO₂CH(CH₃)₂ (where R is 2-bromo-5-methoxy, 3-bromo-4-methoxy, 5-bromo-2-methoxy, 2-chloro-3-methoxy, 3-chloro-4-methoxy, 2-chloro-6-methyl, 2-fluoro-6-methyl, 3-fluoro-2-methyl, 3-fluoro-4-methyl, 4-fluoro-2-methyl, 4-fluoro-3-methyl) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and isopropyl cyanoacetate and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200-500ºC range with residue (1-8% wt.), which then decomposed in the 500-800ºC range.