The electrocopolymerization of o-toluidine (OT) and p-phenylenediamine (PPDA) on a platinum electrode in a solution of 0.5 mol/dm³ H₂SO₄ with cyclic voltammetry was examined. The addition of PPDA to the solution of OT in 0.5 mol/dm³ H₂SO₄ accelerated the electrocopolymerization of OT and PPDA. Fourier transform infrared spectroscopy and ultraviolet–visible spectra for the polymers showed that the unit of PPDA should have been integrated into the backbones of the copolymers to form phenazine-like ring structures, and the delocalization of electrons in the copolymer was better than that in poly(o-toluidine) (POT). The scanning electron microscopy (SEM) images for the polymers showed that the copolymers became more porous, and smaller particles, which made oxygen, oxidized the reduced copolymer more easily and faster. It was proven with SEM, energy-dispersive X-ray spectroscopy, and transmission electron microscopy that the size of the nanoplatinum particles deposited on the copolymer reached 10 nm and was much smaller than those on POT. They had better tolerance to the poisoning species arising from the intermediates of the dissociation of methanol on a platinum electrode during the electrocatalytic oxidation of methanol. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The reduction of benzophenone was investigated in five different ionic liquids by using transient cyclic voltammetry, near steady-state voltammetry, and numerical simulation. Two reversible, well-resolved one-electron-reduction processes were observed in dry (≤20 ppm water, ca. 1 mM)) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpyrd][NTf₂]) and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide ([Bmpipd][NTf₂]), which did not contain any readily available proton source. Upon addition of water, the second process became chemically irreversible and shifted to a more positive potential by approximately 600 mV; moreover, the two reduction processes merged into a single two-electron proton-coupled process when about 0.6 M H₂O was present. This large dependence of potential on water content, which was not observed in molecular solvents (electrolyte), was explained by a reaction mechanism that incorporated protonation and hydrogen-bonding interactions of the benzophenone dianion with as many as seven water molecules. In the three imidazolium-based ionic liquids used herein, the first benzophenone-reduction process was again reversible, whilst the second reduction process became chemically irreversible owing to the availability of the C2-H imidazolium protons in these ionic liquids. The reversible potentials for benzophenone reduction were remarkably independent of the identity of the ionic liquids, thereby implying either weak interactions with the ionic liquids or relatively insignificant differences in the levels of ion-pairing. Thus, the magnitude of the separation of the potentials of the reversible first and irreversible second reduction processes mainly reflected the proton availability from either the ionic liquid itself or from adventitious water. Consequently, voltammetric reduction of benzophenone provides a sensitive tool for the determination of proton availability in ionic liquids.

Under the conditions of potentiostatic electrolysis, the electropolymerization of o-toluidine (OT) and para-phenylenediamine (PPDA) and the electrocopolymerization between OT and PPDA on an indium tin oxide (ITO) conductive glass electrode at potentials of 0.7, 0.8, and 0.9 V were studied in detail by in situ ultraviolet–visible (UV–vis) spectrometry in 0.5 mol/L sulfuric acid media. It was shown that both OT and PPDA could be electropolymerized on the ITO electrode, which depended on the applied electrolysis potential and the concentration of the monomer. Furthermore, in situ UV–vis spectra indicated that the electrocopolymerization between OT and PPDA could happen. The presence of PPDA not only promoted polymerization but also accelerated polymerization, which was attributed to the formation of an intermediate result from the coupling of PPDA and the toluidine monomer cation radical. PPDA could be incorporated into the copolymer to make the copolymer have a phenazine or phenazine-like cyclic structure, which was proven by the reflectance Fourier transform infrared spectra of the polymer and copolymer. The scanning electron microscopy morphology images of the polymers obtained showed that, in addition to accelerating polymerization, PPDA also could change the method of nucleation for the polymer to make the copolymer possess a fibrous surface morphology. The diameter of the fibroid copolymer was about 100 nm, and the length of that reached about 1000 nm. In the article, a newer concerned mechanism of copolymerization was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

In the one compartment electrochemical cell 2-hydroxy-2-p-tolyl-butyric acid methyl ester was electrosynthesized by electrochemical carboxylation of p-methylpropiophenone in the presence of carbon dioxide. Under galvanostatic conditions, the electrocarboxylation was influenced by supporting electrolytes, cathode materials, the current density, passed charge and temperatures. Application scope of the eletrocarboxylation system was then examined, and an excellent yield of 97% was obtained when the electrolysis was carried out in DMF-0.1 mol·L⁻¹ TEABr solution using cheap and environmentally benign nickel as the cathode under a controlled current density of 5.0 mA·cm⁻² until 2.8 F·mol⁻¹ charge passed through the cell at −10°C. The electrochemical behavior of p-methoxylacetophenone has been studied on the glassy carbon electrode by cyclic voltammetry and the probable mechanism was proposed accordingly.

Polypyrrole (PPy) films were electropolymerized on Pt and indium-tin-oxide (ITO) electrodes in a room temperature ionic liquid, 1-buthyl-3-methylimidazolium hexafluorophosphate (bmimPF₆). The ionic liquid was used as both the growth medium and the supporting electrolyte. The cyclic voltammetry (CV) shows that the growth of polymer, prepared in ionic liquid was not similar to that prepared in traditional organic media. The polymer was further characterized via AC impedance, in situ UV-Visible spectroscopy, scanning electron microscopy (SEM), Raman and Fourier transform infrared spectroscopy (FTIR). Both Raman and FTIR spectroscopy results show the characteristic peak of PPy. SEM shows the morphology differences between the both sides of the polymer. The electrocatalytic effect of the PPy modified electrode was investigated in hydroquinone solution and the result exhibited electrocatalytic properties for hydroquinone by the PPy modified electrode.

The feasibility of electrocarboxylation of benzyl chloride has been investigated at silver cathode in CO₂-saturated room-temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄) solution for the first time. The electrochemical behavior was studied at different electrodes by cyclic voltammetry, which showed significant electrocatalytic effect of the silver electrode on the reduction of benzyl chloride. The highest yield of 45% of phenylacetic acid was obtained under optimal conditions. The recovered ionic liquid was reused for four times with gradual decrease in the yield of phenylacetic acid.

The electrochemical reduction and carboxylation of ethyl cinnamate have been carried out in an undivided cell equipped with a Mg sacrificial anode using MeCN as solvent. Direct electroreduction led to the formation of the hydrodimers and saturated ester. And electrocarboxylation was carried out in the presence of CO₂. The global yield and the ratio of mono- to dicarboxylic acids were strongly affected by various factors: electrode material, electrolysis potential, the substrate concentration and temperature. The high yield (78%) was obtained under an optimized reaction condition (cathode: Ni; electrolysis potential: −1.7 V; substrate concentration: 0.1 mol·L⁻¹; and temperature: −10 °C).

A new electrochemical synthesis of 2-anisidine from 2-nitroanisole has been developed in room-temperature ionic liquid (RTIL), which was carried out under mild and safe conditions, where the volatile, toxic solvents, catalysts, as well as any additional supporting electrolyte were avoided. The maximal yield of 2-anisidine reached 51.3% on Cu-graphite couple electrodes under potentiostatic electrolysis at −1.0 V (vs. SCE) until 6 F·mol⁻¹ of charge was passed at 50 °C, which offers a new and clean route to synthesis of 2-anisidine. The reduction behavior of 2-nitroanisole was studied in RTIL by cycle voltammertry. The RTIL could be recycled.

Electrocarboxylation of acetophenone with CO₂ to obtain 2-hydroxy-2-phenylpropionic acid was carried out in acetonitrile solution containing 0.1 mol·L⁻¹ tetraethylammonium bromide. Influences of the nature of the electrodes, the working potential, the passed charge and the concentration of acetophenone on the electrocarboxylation were studied. After optimizing the synthetic parameters, the maximal isolated yield reached 73.0% on Mg-stainless steel couple electrodes under potentiostatic electrolysis until 2.2 F·mol⁻¹ of charge was passed at 25 °C. The reduction of acetophenone was studied by cyclic voltammetry and the mechanism has been proposed on the basis of the results.