Electrochemical and Chemical Polymerization of Imidazole and Some of Its Derivatives

Abstract

Imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, and benzimidazole were subjected to electrochemical and chemical oxidation. Chemical oxidation yields oligomers with higher molecular weight (DP > 12) than anodic oxidation (DP >6) as detected by laser desorption mass spectrometry (LDMS).The oligomers have a relatively simple structure in which imidazole moieties are linked by N-N bonds.1-Methylimidazole does not polymerize, and benzimidazole seems to react through the benzene carbon atoms as well as through the nitrogen atoms. Solubility of these products varies with the substituent group on the imidazole ring. We propose a variation of Diaz's mechanism of pyrrole polymerization that we base on cyclic voltammetry, spectral analysis, pH effects, laser desorption mass spectrometry, and computer calculations. The mechanism involves stepwise removal of an electron from the N-3 atom to produce a radical cation that then couples. LDMS data suggest that chemical polymerization occurs by rapid dimerization of imidazole followed by slower polymerization of the dimers. LDMS of electrochemical polymerization products suggests that polymerization occurs by addition of one imidazole unit at a time. None of these products exhibits electrical conductivity.

Influence of Iodide Ions Concentration on the Stability of 1-Ethyl-3-methylimidazolium Tetrafluoroborate | Molybdenum Carbide Derived Carbon Electrode Interface

“…systems has been calculated for 1-buthyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide at Pt microelectrode. 54 Results of Wang et al 55 indicated that 1-methylimidazole solution in CH 3 CN started to electrooxidize very slowly at Pt electrode at E > 2.0 V (vs. Ag/Ag + ) forming a very broad current peak with a maximum at E = 3.1 V (vs. Ag/Ag + ). Opposite to other investigated imidazolium compounds, the 1-methylimidazole was unable to give the polymeric products at the mentioned potentials because of (probable) blocking of one imidazolium nitrogen atom bound with the methyl group.…”

Magnetic, electrochemical and optical properties of a sulfate-bridged Co(ii) imidazole dimer

“…As a result of the similarity in oxidation potentials in 1 and 2, this process is assigned to the oxidation of the DMIM ligands, which in their uncoordinated form are known to form free radical species at potentials in this range. 14 The second, less pronounced, irreversible oxidation peak observed at 0.48 V vs. Fc 0 /Fc + is assigned to the Co(II)/Co(III) couple. This redox wave is broad, indicating that the Co(II) centres oxidise simultaneously.…”

Effect of the solvent type and polymerization conditions on the curing kinetics, thermal and viscoelastic performance of poly(amide-imide) resins

“…The lower activation energy in this case can be explained by the catalytic effect of MI for the PAAc-cyclisation. At the same time, this solvent is known for its catalytic effect among other nucleophilic reactions in acidic conditions [16,22,23]. In addition, there is a direct correlation between the basicity and the nucleophilicity: increase of the basicity increases the nucleophilicity [24] and, accordingly, the reaction rate [10,25].…”