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Chemoenzymatic Polymerization of Hydrazone Functionalized Phenol
(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2016) Isci, Irfan; Gokturk, Ersen; Turac, Ersen; Sahmetlioglu, Ertugrul
Hydrazone substituted oligophenol was synthesized via enzymatic oxidative polymerization of (E)-2-((2-phenylhydrazono) methyl) phenol. Enzymatic polymerization catalyzed by Horseradish peroxidase (HRP) enzyme and H2O2 oxidizer yielded oligophenol with hydrazone functionality on the side-chain. Effects of various factors including solvent system, reaction pH and temperature on the polymerization were studied. Optimum polymerization conditions with the highest yield (84%) and molecular weight (M-n = 8 x 103, DP approximate to 37, PDI - 1.11) was achieved using MeOH/pH 6.0 buffer (1 : 1 vol %) at 25 degrees C in 24 h under air. Synthesized oligomer was characterized by H-1 and C-13 NMR, FTIR, UV-Vis spectroscopy, GPC, cyclic voltammetry and thermo-gravimetric analyses. The polymerization involved hydrogen elimination from the monomer, and terminal units of the oligomer structure consisted of phenolic hydroxyl (-OH) end groups. The oligomer backbone possessed phenylene and oxyphenylene repeat units. The resulting oligomer was completely soluble in common organic solvents. The oligomer was thermally robust and exhibited 5% mass loss at 375 degrees C and 50% mass loss at 440 degrees C.