Poly(1,2,4-triazole) via aromatic nucleophilic displacement

US5182356A · kind A · utility

Assignee

• The United States of America as represented by the United States National Aeronautics and Space Administration · US

Inventors

• John W. Connell · Newport News, US
• Paul M. Hergenrother · Yorktown, US
• Peter Wolf · Gaithersburg, US

Key dates

• Filing date: Jan 24, 1991
• Grant date: Jan 26, 1993
• Expiry date: Jan 24, 2011

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G73/08
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Poly(1,2,4-triazoles)(PT) have been prepared by involving the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)-1,2,4-triazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl)-1,2,4-triazole monomers are first synthesized by reacting bis(4-hydroxyphenyl) hydrazide with aniline hydrochloride at 250.degree. C. in the melt and also by reacting 1,3 or 1,4-bis-(4-hydroxyphenyl)phenylenedihydrazide with 2 moles of aniline hydrochloride in the melt. Purification of the di(hydroxyphenyl)-1,2,4-triazole monomers is accomplished by recrystallization. This synthetic route has provided high molecular weight PT of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides.