Electroinduced oxidative copolymerization ofN-vinyl carbazole with methyl ethyl ketone formaldehyde resin

2004 ◽  
Vol 15 (7) ◽  
pp. 365-369 ◽  
Author(s):  
Belkıs Ustamehmetoğlu ◽  
A. Sezai Saraç ◽  
Nilgün Kızılcan ◽  
Ahmet Akar
2011 ◽  
Vol 40 (4) ◽  
pp. 211-221 ◽  
Author(s):  
Belkis Ustamehmetoğlu ◽  
Pelin Yazıcı ◽  
Nilgun Kızılcan

2005 ◽  
Vol 54 (11) ◽  
pp. 1019-1030 ◽  
Author(s):  
Belkıs Ustamehmetoğlu ◽  
Nilgün Kızılcan ◽  
A. Sezai Saraç ◽  
Ahmet Akar

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Belkis Ustamehmetoğlu ◽  
Nesrin Köken ◽  
Nilgun Kizilcan ◽  
Ahmet Akar ◽  
Şebnem Tayyar

Purpose The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV) polymerization method and the electrochemical oxidization of the formed copolymer to produce their conductive green form. The non-conductive and conductive copolymers were characterized by using Fourier transform infrared, solid-state conductivity and spectroelectrochemical, chronoamperometric, cyclovoltammetric and electrochemical impedance spectroscopic measurements. Design/methodology/approach The chronoamperometric electropolymerization of white, insulator form of the copolymer of NVCz and MEKFR (copolymer 1) on to Pt electrode was carried out and the green coloured film of the MEKFR-ox-NVCz copolymer (copolymer 11) was produced in the doped and conductive form. All reactions were performed in dichloromethane containing 0.1 M BU4NClO4. Copolymer 11 films obtained on the surface of the working electrode were removed and washed in acetonitrile and dried at room temperature before characterization. The results were compared with the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). Findings The insulating copolymer of NVCz and MEKFR (copolymer 1) was produced by the electroinduced Ce (IV) polymerization method and converted into the conductive form electrochemically on the surface of the Pt electrode (copolymer 11). The polymers were characterized by electrochemical, spectrophotometric and conductivity measurements. The ionization potentials, optical band gap, peak potentials Ep, doping degree and specific capacitance of the copolymer 11 were obtained. The conductivity of the copolymer 11 is lower than the PNVCz and higher than the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). The copolymer 11 has a lower onset potential than PNVCz and the copolymer 1 and slightly higher band gap than PNVCz. The capacitive behaviours of the copolymer 11 were very close to PNVCz. Research limitations/implications This study focuses on obtaining a green and conductive form of the copolymer of NVCz and MEKFR with the electrochemical method by using a white and insulator form of the same copolymer. Practical implications This work provides technical information for the synthesis of conducting copolymer of NVCz and MEKFR. Social implications These copolymers may be in the field of PNVCz applications such as photoconductivity and corrosion inhibition. Originality/value Electroinduced Ce (IV) MEKFR redox system was applied for the polymerization of NVCz monomer to produce the copolymer 1. The conductive copolymer 11 was synthesized through electrochemical oxidative coupling of the carbazole groups of the copolymer 1.


2012 ◽  
Vol 41 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Belkis Ustamehmetoğlu ◽  
Ahmet Akar ◽  
Nilgun Kizilcan ◽  
Eda Kelleboz

2014 ◽  
Vol 34 (1) ◽  
pp. 243-250
Author(s):  
Jianghong DING ◽  
Le XU ◽  
Hao XU ◽  
Haihong WU ◽  
Yueming LIU ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3317
Author(s):  
Maria Carolina Pereira Gonçalves ◽  
Jéssica Cristina Amaral ◽  
Roberto Fernandez-Lafuente ◽  
Ruy de Sousa Junior ◽  
Paulo Waldir Tardioli

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.


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