PROCESS FOR THE PREPARATION OF A POLY(PHENYLENE ETHER) PROTECTED AGAINST MOLECULAR-WEIGHT DEGRADATION, IN WHICH THE COPPER SALT, USED IN THE COUPLING REACTION, CAN BE USED AGAIN

摘要

Polyphenylene ethers (PPO) protected against mol.wt. degradation are produced by 1) terminating the oxidative coupling reaction of di-ortho-substd. phenols and sepn. of the Cu component, in a reaction medium for the oxidative coupling reaction chosen from i) 1-4C chlorinated hydrocarbon, ii) 6-8C aromatic solvent or iii) a mixt. of i) and ii) and 1-6C alcohol or ketone in a vol. ratio of 92.5:7.5-50:50 with the constraint that during the oxidative coupling reaction the PPO remains in soln. 2) removing the O2 needed for the coupling reaction, 3) treating the reaction soln. with hydrazine or hydrazine soln., 4) sepg. the ppte. Pref. the O2 or the reaction gas contg. O2 is expelled using an inert gas e.g. N2 or Ar. During the oxidative coupling reaction sufficient O2 is introduced so that the total amt. is consumed on attaining the desired deg. of polymerisation. The reaction soln. is treated with hydrazine or a soln. contg. hydrazine at between 20-100, esp. 40-70 deg.C. The hydrazine:Cu mol. ratio is between