Di(hydroxyphenyl)-1,2-4-triazole monomers

US5245043A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the 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: Jun 29, 1992
• Grant date: Sep 14, 1993
• Expiry date: Jun 29, 2012

Classification

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

Abstract

The di(hydroxyphenyl)-1,2,4-triazole monomers were 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)phenylene-dihydrazide with 2 moles of aniline hydrochloride in the melt. Purification of the di(hydroxyphenyl)-1,2,4-triazole monomers was accomplished by recrystallization. Poly(1,2,4-triazoles) (PT) were prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)-1,2,4-triazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions were carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. 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.