Abstract: Crude diphenyl phthalates, including isomeric mixtures thereof which are prepared by reacting mixtures of isophthalic and terephthalic acids with phenol, preferably in the presence of an organotitanate, organozirconate, or organostannate catalyst, are purified by dissolving the crude phthalate in an organic solvent, contacting the resulting solution with dilute aqueous alkali to neutralize the ester, separating the resulting oil and aqueous phases, and thereafter recovering from the oil phase a purified diaryl phthalate of reduced color and low acidity.

Abstract: An oxymethylene polymer composition which exhibits improved thermal stability is provided by utilizing as a stabilizer a major amount of superpolyamide and a minor amount of a transition metal salt.

Abstract: Oxymethylene polymers are prepared by the continuous polymerization of trioxane using as a catalyst a blend of boron trifluoride gas and nitrogen gas. Oxymethylene polymers are used in the manufacture of plumbing fixtures, pipes, automobile body parts and a variety of other articles.

Abstract: Polyester molding composition containing polybutylene terephthalate, nucleated polyethylene terephthalate or mixtures thereof as well as thermally stable reinforcing fibers and polyphenylene sulfide having a melt flow rate of less than about 1,000.

Abstract: Poly(C.sub.2 -C.sub.4 alkylene terephthalate) molding composition containing aromatic polyester carbonate and impact modifier. The aromatic polyester carbonate is derived from a dihydric phenol, a carbonate precursor and dicarboxylic acid or ester forming derivative thereof. The impact modifier may be a core-shell polymer polymerized from monomers comprising butadiene or may be a core-shell polymer having a first elastomeric phase polymerized from a monomer system including C.sub.1 -C.sub.6 alkylacrylate as well as crosslinking and graftlinking monomers and having a final rigid thermoplastic phase polymerized in the presence of the elastomeric phase.