THE MECHANISM OF CHAIN GROWTH IN OXIDATIVE POLYCONDENSATION OF PHENOLS

A new mechanism of chain extension in oxidative polycondensation of ph enols has been proposed. Between the two accepted mechanisms: quinol e ther redistribution and quinol ether rearrangement, the second mechani sm seems to be the most important for the chain growth. The first mech anism, quinol ether redistribution, preserves the system average degre e of polymerization and assures a permanent equilibration of the polym eric chains, but has only a minor contribution to the molecular weight increase. The second mechanism, quinol ether rearrangement, proved to be the most important for chain extension and was interpreted as a re peated Claisen rearrangement (a particular case of a sigmatropic rearr angement), characteristic to allyl ethers of phenols. Experimental dat a proved that the above mentioned mechanisms probably take place simul taneously and the real growth of the molecular weight is a result of t he cumulative contributions of both mechanisms.