Abstract: Disclosed are processes for preparing monomer complexes that include contacting 2,3,5,6-tetraaminopyridine free base in water with 2,5-dihydroxy terephthalic acid dipotassium salt to form an aqueous mixture, and adjusting the pH of the aqueous mixture to within the range of from about (3) to about (5) to precipitate the monomer complex. Processes of polymerizing the monomer complexes, polyareneazoles, filaments and yarns are also disclosed.

Abstract: The present invention relates to fibers comprising polyareneazole polymer having pendant hydroxyl groups and cations.

Abstract: The present invention concerns a process for making a polyareneazole multifilament yarn comprising: a) extruding a solution comprising polyareneazole polymer and polyphosphoric acid through a plurality of orifices to produce filaments; b) forming a multifilament yarn from said filaments; c) hydrolyzing at least some of the polyphosphoric acid in the yarn by heating the yarn to a temperature above about 120° C. for up to about two minutes; d) washing at least some of the hydrolyzed polyphosphoric acid from the yarn; e) drying the washed yarn; f) optionally, heating the yarn above about 300° C., and g) collecting the yarn at a speed of at least about 50 meters per minute.

Abstract: A process is disclosed for dicarboxylating dihydric phenols, notably those where the hydroxyl groups are in the para or the ortho position vis-a-vis one another. More particularly, the invention pertains to a process for preparing 2,5-dihydroxyterephthalic acid (2,5 DHTA). The invention comprises contacting a dihydric phenol with carbon dioxide in the presence of an alkali metal carbonate, the reaction being carried out in the presence of an alkali metal formate, at a temperature above the formate's melting point. The invention has several advantages over the well-known Kolbe-Schmitt reaction and other known carboxylation reactions, such as a lower operating pressure, higher yields, and/or shorter reaction times.

Abstract: It has been found that the nitration of pyridine-2,6-diamines, which is commonly performed in a mixture of nitric acid and concentrated sulfuric acid, will give a significantly higher yield (from about 50% up to more than 90%) if the reaction is carried out in a mixture of nitric acid and oleum, or by otherwise providing an inherently anhydrous medium.

Abstract: A process has been found for preparing pyridine-2,6-diamines, i.e., 2,6-diaminopyridine (DAP) and derivative compounds in which one of the amino groups is a substituted amine (secondary or tertiary). According to this process, 3-hydroxy pentane 1,5-dinitrile (3-hydroxyglutaronitrile) is reacted with an ammonium donor in the form of ammonia, a primary amine such as n-butylamine, or a secondary amine such as piperidine.

Abstract: A rigid rod polymer in which at least 50% of the recurring groups correspond to the formula; ##STR1## Included in the invention are processes for preparation of the above rigid rod polymer and using such polymer as well as compositions employing the above rigid rod polymer.