Studies of tetrazoles as rubber chemicals. I. Preparation and characterization of reactive antioxidants based on tetrazoles

✍ Scribed by S. Otomo; T. Sako; Y. Yamamoto; S. Yamashita

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 464 KB
• Volume: 28
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1983.070281208

✦ Synopsis

The novel reactive antioxidants based on tetrazoles that are stable a t 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'-ditert-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 3141% yields. To evaluate the reactivities of P H P T for carbon-carbon double bonds, rn-chloro-substituted P H P T was pyrolyzed in an excess of styrene a t 160-170°C for 0.5 h to give the 1-(3'-chloropheny1)-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 rn-chloro-substituted PHPT. The thermogravimetric analysis of a mixture of proton isomer of P H P T and liquid polybutadiene showed that P H P T attached to liquid polybutadiene with an accompanying evolution of nitrogen.