Preparation of cyclic oligomeric alkylene phthalates via pseudo-high dilution condensation of alkylene diols with iso- and terephthaloyl chlorides and conversion to high molecular weight polyesters via ring-opening polymerization is described. Sterically unhindered amines such as quinuclidine or 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyze the condensation significantly faster than other tertiary amines and are useful for carrying out this conversion in high yield, in the first direct reaction of diol and diacid chloride to form cyclic polyesters. The mixtures of oligomeric cyclics melt at 150-200 degrees C, providing liquids of low viscosity. Ring-opening polymerization using tin or titanate catalysts affords high molecular weight polymers within minutes. Complete polymerization of PBT oligomeric cyclics can be achieved at 180-200 degreesC, significantly below the polymer's melting point of 225 degreesC, and with molecular weights as high as 445 x 10(3). Polymers formed via such a process are more crystalline than conventionally prepared polyesters.

Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion is a versatile and useful reaction for the synthesis of aromatic ethers. Preparation of various aromatic monomers and polymers containing ether linkages is described.

The polymerization and characterization of the ether‐containing aromatic polyimides of the following general structure are presented. The polymerization was conducted in one step in homogeneous solution of m‐cresol at high temperatures. Typical polyeterimides (PEI) were noncrystalline and showed excellent thermal stability. Among 46 polymers synthesized, only two were crystalline. PEI had glass transition temperatures from 178° to 277°C and exhibited excellent processibility. Many PEI were also soluble in dipolar aprotic solvents and chlorinated hydrocarbons.

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A general synthetic method and characterization of bis(ether anhydride)s, the ether containing aromatic dianhydrides of the following structure, are presented. magnified image The method involves aromatic nitro‐displacement of N‐substituted 3‐ or 4‐nitrophthalimide with bisphenoxides to form N‐substituted arylene‐bis(phthalimido)ethers or bis(ether imide)s. Sixteen structurally different bis(ether imide)s have been prepared and subsequently converted to the corresponding bis(ether anhydride)s. Bis(ether anhydride)s are stable crystalline compounds of a moderate reactivity. Unlike highly reactive dianydrides such as pyromellitic and benzophenonetetracarboxylic dianhydrides bis(ether anhydride)s are semipermanently stable against hydrolysis in the presence of atmospheric moisture.