Arloxy p-phenylene diamines

#This invention relates to substituted P-phenylene diamines.

#Considerable research effort has been directed toward the synthesis of rigid rod polymers for their unique ordering properties that provide extremely high modulus/high strength films and fibers. One class of materials of particular interest is the aromatic heterocyclic bisbenzazole polymers. These polymers exhibit excellent thermal and thermooxidative stabilities. Another class of materials having comparable high temperature properties is the aromatic polyimides. The polyimides are attractive, not only for their high temperature properties, but also because of the low cost of the diamine and dianhydride monomers used in their synthesis.

#An aromatic polymide with the desired para-ordered geometry and be prepared from pyromellitic dianhydride (PMDA) and p-phenylene-diamine. High molecular weight polyamic acid has been prepared in dimethylacetamide (DMAC) using these monomers; however, thermal or chemical cyclodehydration leads to an insoluble, infusible material. Fabrication of this material is normally carried out via the DMAC-soluble polyamic acid which produces two units of water per repeat unit during high temperature thermal cyclodehydration to the imide structure. The water produced by this process limits the utility of this material, particularly in the fabrication of thick components.

#The following examples illustrate the invention:

#100 g (0.724 mol) of p-nitroaniline was slowly added to 1550 ml of glacial acetic acid at 40.degree. C. After cooling the solution to 20.degree. C., 37.4 ml (116.65 g, 0.730 mol) of bromine was added dropwise over a period of one h, after which the solution was allowed to stir an additional 45 min. at 20.degree. C. The precipitate which formed during the reaction was collected by suction filtration and stirred with 2500 ml of 10% aqueous sodium bisulfite for 16 h; collected again by suction filtration and washed with 2500 ml of water. The solid was air-dried for 24 h. The crude material (139 g) was recrystallized twice from 65% methanol to yield 103 g (65.6%) of a yellow crystalline solid which melted at 101.degree.-102.degree. C.; IR (KBr) 3500, 3400, 1125 cm.sup.-1 (NH.sub.2); 1500, 1325 (NO.sub.2).

#Anal. Calcd. for C.sub.6 H.sub.5 N.sub.2 O.sub.2 Br: C,33.18; H, 2.30; N, 12.90. Found: C, 33.26; H, 2.28; N, 12.92.