Enzymatic oxidative polymerization of pyrogallic acid for preparation of hindered phenol antioxidant

Abstract

A novel antioxidant with high molecular weight was successfully synthesized via horseradish peroxide-catalyzed oxidative polymerization of pyrogallic acid. As-synthesized poly(pyrogallic acid), a black powder completely soluble in common organic solvents, has a number-averaged molecular weight of about several thousand and consists of phenylene and oxyphenylene units. Besides, as-prepared poly(pyrogallic acid) exhibits much better thermal stability and antioxidant capacity than butylated hydroxyanisole (denoted as BHA) and butylated hydroxytoluene (denoted as BHT), two kinds of commercial antioxidants. And it was also found that the higher phenolic content the pyrogallic acid polymer possess, the better antioxidant activity the poly(pyrogallic acid) shows. More importantly, poly(pyrogallic acid) could effectively inhibit the oxidation degradation of polypropylene (denoted as PP) during plastic processing.

Sodium alginate/carboxymethyl cellulose films containing pyrogallic acid: physical and antibacterial properties

“…The peaks at 1619, 1518, 1480, 828, 764 and 716 cm −1 are assigned to various vibration modes of C‐C and C‐H bonds of the aromatic nuclei. Furthermore, a peak at 1065 cm −1 is ascribed to the symmetric vibration of the ether bond . The FT‐IR spectra of F1, F2, F3 and F4, which incorporated various concentrations of PA, display IR absorbance patterns similar to those of the control films.…”

“…These results can be attributed to the higher PA content opening the polymeric structure, allowing more charged sites to be accessible to water molecules. PA itself is very hygroscopic and therefore is probably responsible for most of the water uptake …”

Radical-Mediated Enzymatic Polymerizations

“…In a demonstration of how enzymatic polymerization leads to the facile synthesis of functional macromolecules, Cui and coworkers polymerized pyrogallic acid to generate moderately-high molecular weight polymers [ 90 ]. Adding HRP and hydrogen peroxide to pyrogallic acid solutions in water/solvent blends, again necessary to solubilize both the monomers and generated polymer, resulted in poly(pyrogallic acid) polymers with M n as high as 39 kg/mol; these materials were found to have excellent antioxidant properties, exceeding those of commonly-used commercial materials.…”

Enzi̇mati̇k Oksi̇dati̇f Poli̇meri̇zasyon İle Orto-Hi̇drazon-Fonksi̇yonlu Oli̇gofenol Sentezi̇

“…HRP enziminin pH≈3'te katalitik olarak aktif olmadığı bilinmektedir, bu yüzden pH <5,0 şartlarında çalışılmamıştır [24]. Literatürde, bazik bölge ve pH >9,0'da HRP enziminin daha düşük katalitik aktivite gösterdiğini rapor etmişlerdir [25]. Bu yüzden pH >9,0 olduğu şartlarda polimerizasyon düşünülmemiştir.…”