Synthesis and properties of α-substituted benzylpyridinium salts as cationic initiators

✍ Scribed by S. Nakano; T. Endo

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 397 KB
• Volume: 34
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199602)34:3<475::aid-pola16>3.0.co;2-m

✦ Synopsis

SYNOPSIS

a-Methylbenzylpyridinium SbFs ( l a ) and a,a-dimethylbenzylpyridinium SbFs (lb) were prepared and the effect of a-methyl groups on the active species and the activity of la, l b during the cationic polymerization of glycidyl phenyl ether (GPE) was evaluated. l b was prepared by the reaction of a,a-dimethylbenzyl alcohol with pyridinium hexafluoroantimonate (2) in several solvents, and the yield depended on the dipole moment of the solvents, although it was poor for the reaction of a,a-dimethylbenzyl chloride with pyridine for the steric hindrance of the a-methyl groups followed by exchange with NaSbFG. Both l a and l b acted as a latent thermal initiator during the cationic polymerization of GPE and l b showed higher activity during cationic polymerization with the higher steric effect of the a-methyl groups than la. The 'H-NMR analysis of the obtained poly GPE indicated that the active species of l b changed from the benzyl cation to H+, depending on the reaction temperature, although l a released benzyl cations as active species in the cationic polymerization of GPE.