ordinary the content of the autoclave was warmed to room temperature thereafter the content of the autoclave was reacted for 48 hours at 120 u00b0 c and after purging phosgene and hydrogen chloride the reaction mixture was added to 100 ml of methanol after collecting the thus formed polymer by filtrating the mixture the thus collected polymer was washed two times with each 100 ml of hot methanol two times with each 100 ml of a hot aqueous 2 solution of sodium hydroxide two times with each 100 ml of a hot aqueous 5 solution of hydrochloric acid two times with each 200 ml of distilled water and once with 200 ml of methanol in the order and then the thus washed polymer was dried in vacuum at 120 u00b0 c for 24 hours the yield of the thus obtained polymer was 100 on the basis of diphenyl ether when the thus obtained polymer was dissolved into 97 sulfuric acid at a concentration of 1 g of the polymer dl and the solution was subjected to determination of the viscosity to know that u03b7 inh was 0 95 dl g in the infrared absorption spectrum of the thus obtained polymer an absorption max at 1240 cm 1 corresponding to aromatic ether and an absorption max at 1650 cm 1 corresponding to.