Nucleophilic substitution in PVC. Additional NMR proof of the conformational mechanism

✍ Scribed by J. Millan; G. Martinez; M.L. Jimeno

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 296 KB
• Volume: 27
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(91)90171-j

✦ Synopsis

By utilizing some new 13 C-NMR spectra of very high resolution, the contents of ram, mr and rr triads and of mmmm, mnunr and rmmr pentads of PVC after nucleophilic substitution to various degrees (ranging between 0 and 10%) could be measured very accurately. Moreover, the content of nunmmrx (x = m, r) and rmmmrx (x = m, r) isotactic heptads could be estimated semiquantitatively. The evolution of these bands allows both to confirm that the reaction proceeds preferably by nun triads, as already found in earlier work, and to assess that only nun triads in ... mmr.., sequences are reactive and that the reactivity is higher as the length of the isotactic sequence ending with nmar increases. These results support the conformational mechanism of substitution proposed earlier.