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    ENVIRONMENTALLY FRIENDLY ENZYME-CATALYZED POLYMERIZATION OF A NOVEL PHENOXY-KETIMINE
    (Gh Asachi Technical Univ Iasi, 2017) Tapan, Senem; Sahmetlioglu, Ertugrul; Demir, Haci Okkes; Turac, Ersen; Sahin, Elif
    The monomer with ketimine side group, 2-(1-(benzylimino) ethyl) phenol (2-BEP), was synthesized from the condensation of 2-hydroxyacetophenone and benzyl amine. The enzymatic oxidative polymerization of 2-BEP was performed in the presence of hydrogen peroxide using horseradish peroxidase (HRP) as catalyst. The oxidation reaction was carried out in various solvents and phosphate buffers at room temperature. These studies have shown that a dark brown polymer was successfully synthesized by utilizing aqueous methanol as the cosolvent at pH 7.0. Poly(2-BEP) shows good solubility in DMF and DMSO, but it is insoluble in THF, methanol, water, acetone and chloroform. Characterization of poly(2-BEP) was carried out via UV-vis, FT-IR, H-1-NMR, C-13-NMR and GPC techniques. The number-average molecular weight (M-n), weight-average molecular weight (M-w) and polydispersity index (PDI) of the polymer were determined to be 1157.4 g mol(-1), 2039.6 g mol(-1) and 1.76, respectively. FTIR and H-1-NMR studies confirmed the presence of phenylene and oxyphenylene units within the polymer backbone. The optical band gaps (E-g) of 2-BEP and poly(2-BEP) were calculated as 4.10 eV and 3.86 eV, respectively.
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    Horseradish peroxidase-catalyzed polymerization of ortho-imino-phenol: Synthesis, characterization, thermal stability and electrochemical properties
    (ELSEVIER SCIENCE BV, 2017) Topal, Yasemin; Tapan, Senem; Gokturk, Ersen; Sahmetlioglu, Ertugrul
    Enzymatic polymerization of phenols has been investigated extensively over the last decades. However, involving imine functional group in the side chain of an oligophenol and its effect on polymerization is poorly understood. Therefore, the influence of the imine functionality in the side chain of oligophenol for enzymatic polymerization is explored in this work. Ortho-imine substituted phenol, (E)-2-((p-tolylimino) methyl) phenol (PTIMP), was enzymatically polymerized using horseradish peroxidase (HRP) enzyme in aqueous organic solvents and hydrogen peroxide (H2O2) as an oxidant. Different parameters (solvent system, pH and reaction temperature) on polymerization were investigated. EtOH/pH 6.0 buffer (50: 50 vol.%) at 25 degrees C in 24 h under air was found to be the optimum polymerization condition with 65% of yield and Mn = 6100 g/mol (DP approximate to 29, PDI = 1.09). Polymerization of PTIMP in the presence of HRP enzyme catalyst leads to the formation of an oligophenol containing phenylene and oxyphenylene repeat units. The resulting oligophenol is soluble in most of the organic solvents. Characterization of oligo(PTIMP) was achieved by NMR, UV-Vis, CV, FT-IR spectroscopy and thermogravimetric analysis. (C) 2017 King Saud University. Production and hosting by Elsevier B. V. This is an open access article under the CC BY-NC-ND license.
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    Yeni tip fenol türevli monomerlerin enzim katalizörleriyle oksidatif polimerizasyonu
    (Niğde Üniversitesi / Fen Bilimleri Enstitüsü, 2012) Tapan, Senem; Şahmetlioğlu, Ertuğrul
    Bu çalışmada öncelikle schiff baz türevi 2-(1(benzilimino)etil)fenol monomeri kondenzasyon reaksiyonu ile sentezlenmiştir ve monomerin kimyasal yapısı UV?vis, FT-IR, 1H-NMR, 13C-NMR spektroskopileriyle karakterize edilmiştir. 2-(1(benzilimino)etil)fenol'ün enzimatik oksidatif polimerizasyonu oksitleyici ajan ve katalizör olarak hidrojen peroksit varlığında HRP kullanılarak oda sıcaklığında değişik çözücü ve fosfat tamponlarında (pH: 3, 4, 5, 6, 7, 8) gerçekleştirilmiştir. Optimum şartlar belirlenmiştir. Çalışmalar koyu kahve renkli polimerin, çözücü olarak sulu metanolün kullanıldığı pH: 7 fosfat tamponunda başarılı bir şekilde sentezlendiğini göstermiştir. P(2-(1(benzilimino)etil)fenol)'ün karakterizasyonu UV?vis, FT-IR, 1H-NMR, 13C-NMR, GPC analiz teknikleri ve tarama hızı çalışması yoluyla gerçekleştirilmiştir.