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Studies of tetrazoles as rubber chemicals. I. Preparation and characterization of reactive antioxidants based on tetrazoles
Author(s) -
Otomo S.,
Sako T.,
Yamamoto Y.,
Yamashita S.
Publication year - 1983
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1983.070281208
Subject(s) - pyridine , chemistry , reactivity (psychology) , polybutadiene , thermogravimetric analysis , polymer chemistry , styrene , organic chemistry , yield (engineering) , pyrolysis , solvent , copolymer , materials science , polymer , medicine , alternative medicine , pathology , metallurgy
The novel reactive antioxidants based on tetrazoles that are stable at room temperature and convertible into the highly reactive nitrileimines by pyrolysis were prepared and the reactivity for carbon–carbon double bonds was evaluated. Antioxidants, i.e., 2‐substituted phenyl‐5‐(3′,5′‐di‐ tert ‐butyl‐4′‐hydroxyphenyl)tetrazoles (PHPT) were prepared with the reaction of p ‐toluenesulfonylhydrazone of 3,5‐di‐ tert ‐butyl‐4‐hydroxybenzaldehyde and substituted phenyl diazonium chloride in a mixed solvent of pyridine, ethanol, and water at −10°C to −20°C in 31‐61% yields. To evaluate the reactivities of PHPT for carbon–carbon double bonds, m ‐chloro‐substituted PHPT was pyrolyzed in an excess of styrene at 160–170°C for 0.5 h to give the 1‐(3′‐chlorophenyl)‐3‐(3″,5″‐di‐ tert ‐butyl‐4″‐hydroxyphenyl)‐5‐phenyl‐2‐pyridazoline in a 44.1% yield by 1,3‐dipolar addition reaction of the nitrileimine formed from the m ‐chloro‐substituted PHPT. The thermogravimetric analysis of a mixture of proton isomer of PHPT and liquid polybutadiene showed that PHPT attached to liquid polybutadiene with an accompanying evolution of nitrogen.