Abstract: There is disclosed a method for purifying a used aqueous N-methylmorpholine N-oxide solution reclaimed from a spinning aqueous solution, which results from a coagulation solution into which a cellulose dope containing N-methylmorpholine N-oxide is extruded through a spinning die and from a washing solution for the coagulated cellulosic articles in manufacture processes for cellulose fibers or films, comprising adding an oxidant to the used aqueous N-methylmorpholine N-oxide solution to remove impurities therefrom through oxidation N-methylmorpholine into N-methylmorpholine N-oxide and break down of the chromophores of the impurities. Utterly distinguished from, conventional methods in the principle, the method is very simple and efficient as well as far superior to the conventional methods using ion exchange resin in the decoloration. In addition, it needs not suffer a loss of amine oxide as usual in the ion exchange resin.

Abstract: This specification discloses pelletized pre-dope granules of cellulose and a tertiary amine oxide wherein the tertiary amine oxide is homogeneously dispersed throughout the cellulose and a process for making them. According to the invention, the pelletized pre-dope granules can be prepared by a process comprising of the steps of feeding cellulose to a mill with knife-edged blades, together with the tertiary amine oxide powder having a water content of 5 to 17% by weight; and milling and blending the resulting solid mixture in the blender, while heating the solid mixture at a temperature sufficient to agglomerate as a result of instantaneous melting of tertiary amine oxide powder and simultaneous penetration of the molten amine oxide into cellulose without dissolving the cellulose. The pre-dope granules thus obtained can be used in making shaped cellulosic articles such as fibers and films.

Abstract: New wholly aromatic polyamides are provided. This polymers are prepared by a mixture of N,N'-bis(4-aminophenyl)-isophthalamide and p-phenylenediamine in a tertiary amide solvent containing an alkali metal salt such as LiCl and a tertiary amine as an acid acceptor. The polymers are easily dry-jet spun to form a fiber and cast to form a film. The fiber and film so obtained have ultrahigh tenacity, elasticity and elongation.

Abstract: High molecular weight block copolyamides useful in the production of fibers of high strength and modulus, having the following formula: ##STR1## wherein X is --CH.sub.2 --.sub.m, wherein m is 0 to 12, ##STR2## wherein Z is C(CH.sub.3).sub.2, zero, oxygen or SO.sub.2, are prepared from N,N'-bis(4-aminophenyl) terephthalamide having the formula: ##STR3## which is itself prepared by condensing aniline with dimethyl terephthalate or terephthalic acid, nitrating the product produced thereby and finally hydrogenating the resultant compound.

Abstract: 5,6-Dihydro-2-methyl-1,4-oxathiin derivatives are prepared by chlorinolysis of an appropriate 1,3-oxathiolane derivative to generate alkene-sulfenyl chloride, followed by cyclization and loss of hydrogen chloride to form said product.

Abstract: 5,6-Dihydro-2-methyl-1,4-oxathiin derivatives are prepared by chlorinolysis of an appropriate 1,3-oxathiolane derivative to generate alkene-sulfenic acid, followed by cyclization and loss of hydrogen chloride to form said product.

Abstract: 5,6-Dihydro-2-methyl-1,4-oxathiin derivatives are prepared by converting an appropriate 1,3-oxathiolane derivative to its sulfoxide and subjecting the sulfoxide to acid catalyzed rearrangement to form the desired product.