Akzona Incorporated

Akzo N.v.

Anton Toth

Gerhard Meyer

Dieter Laudien

A process for the production of 3-hydrazino-4-amino-5-mercapto-1,2,4-triazole wherein hydrazinium-dithiocarbazinate is heated at moderately elevated temperature, e.g. about 50.degree. C. to 85.degree. C. and under reduced pressure, e.g. about 50 to 500 mm. Hg, with at least a 3.times. molar amount of hydrazine hydrate.

Process for producing 3-hydrazino-4-amino-5-mercapto-1,2,4-triazole

A process for the producing a polyamidocarboxylic acid, or so-called polyamic acid, which is the prepolymer in forming a polyamide and which requires the reaction of a tetracarboxylic acid dianhydride with a diprimary diamine below about 50.degree.C. in an anhydrous, polar, aprotic organic solvent, characterized by an initial treatment of the dianhydride by only wetting with an inert organic solvent or by at least wetting this dianhydride with the polar, aprotic solvent and thereafter adding to the wetted dianhydride a solution of the diamine in the polar, aprotic solvent under thorough mixing, preferably within a very short period of time after treating the dianhydride. Stable polyamic acid solutions formed in this manner are useful intermediates in preparing films, filaments or other shaped polyimide products.

Process for the production of polyamidocarboxylic acids

In a process for reacting an aromatic or hydroaromatic alicyclic or heterocyclic dicarboxylic acid or its anhydride with an aliphatic or aromatic alicyclic or heterocyclic mono- or di-amine to produce an N-substituted dicarboxylic acid imide with a splitting off of water, the improvement of carrying out the reaction in a liquid solvent mixture consisting essentially of a non-polar organic solvent and a strongly polar organic solvent which together form a ternary azeotrope with water at reaction temperatures between about 40.degree.C. and 160.degree.C. The imide products are generally known for use as intermediates and final products in a number of industries.

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Obernburg, Germany

Anton Toth