Anionic co-oligomerization of methacrylonitrile and methyl methacrylate

The bulk oligomerization of mixtures of MAN and MMA by NaOCH₃/CH₃OH, was found to lead to the formation of co-oligomers as well as the homo-oligomers. The reaction was followed by gas chromatography; because of the great complexity of the oligomer mixture at the trimer stage and higher, only the dimer mixtures were analysed. The chromatograms showed between the peaks of the homo- dimers of MAN and MMA, which had different retention times, the presence of a codimer. This was isolated by gas chromatography and identified as 1-methoxy-2-carbomethoxy-2-methyl-4-cyano pentane (MeOMMAMAN). While the chromatogram of the dimer of MMA showed only one peak, that of the dimer of MAN showed two peaks. The two isomeric, 1-methoxy-2,4-dicyano-2-methyl pentanes (MeOMANMAN), were separated and were found to be the isotactic and the syndiotactic modifications. Their structures were deduced from NMR and dipole moment measurements.