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Di(hydroxyphenyl)- 1,2,4-triazole monomersThe di(hydroxyphenyl)- 1,2,4-triazole monomers were first synthesized by reacting bis (4-hydroxyphenyl) hydrazide with aniline hydrochloride at 250 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.
Document ID
19940018602
Acquisition Source
Legacy CDMS
Document Type
Other - Patent
Authors
Connell, John W. (NASA Langley Research Center Hampton, VA, United States)
Hergenrother, Paul M. (NASA Langley Research Center Hampton, VA, United States)
Wolf, Peter (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
September 14, 1993
Subject Category
Nonmetallic Materials
Accession Number
94N23075
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-PATENT-5,245,043|NASA-CASE-LAR-14440-2
Patent Application
US-PATENT-APPL-SN-650336|US-PATENT-APPL-SN-905708

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