Poly(cyclopenta [2,1-b;3,4-b′]dithiophen-4-one) (PCDT) has been characterized by several electrochemical and spectroscopic techniques so that it can be used as an active electrode material in electrochemical supercapacitors. This polythiophene derivative was prepared by the electrochemical polymerization of cyclopenta[2,1-b;3,4-b′]dithiophene-4-one (CDT) from a nonaqueous solution (acetonitrile) containing tetraethylammonium tetrafluoroborate. The range of electroactivity of PCDT in nonaqueous media spans at least 2 V. The doping levels measured by cyclic voltammetry and EDAX were found to be 0.19 and 0.14, respectively, for the oxidized-PCDT. Low-frequency capacitance measurements were made by electrochemical impedance spectroscopy to evaluate the film's ability to store charge. Low-frequency capacitances of about ∼70 F/g were found for both the p-and n-doped states. Ionic and electronic resistances were established using both a Randles equivalent circuit and the linear transmission line model to analyze the impedance data of electronically conducting polymers. The film morphology was studied by scanning electron microscopy, and photomicrographs revealed an open and porous structure. X-ray photoelectron spectroscopy was employed to evaluate the electronic properties of the polymer. Negatively charged sulfur atoms were only observed in low content probably due to low negative polaron stability and the sensitivity of the polymer to trace amounts of oxygen and water. Nonetheless, the S 2p σ-species for the n-doped state has clearly been identified in our study as we present here. A conservative estimate of the doping level was found to be ∼0.06. Preliminary galvanostatic charge/ discharge cycling experiments indicated an energy density, E, of about 6 (W h)/kg for the active material with a power density, P, of 1 kW/kg for an 18 s discharge time. These values are above the midterm requirements fixed by the U. S. Department of Energy for electrochemical supercapacitors (E > 5 (W h)/kg and P > 500 W/kg). A discharge capacity decrease was observed during the first 20 cycles but thereafter the discharge capacity remained constant for the next 80 cycles. Additional work is currently under way to improve the stability of the PCDT-based capacitor since this conducting polymer should be very interesting as an active electrode in electrochemical supercapacitors.

A short procedure for the synthesis of 2,2-di(3-thienyl)-1,3-dioxolan is described. The route developed is convenient (only two synthetic and one chromatographic steps are required) and efficient (66% overall yield from 3-bromothiophene). This compound was transformed into the ketone, cyclopenta [2,1-b:3',4'-b']dithiophen-4-one by a known process. Optimized syntheses of symmetric aryl ketones, 1-alkyl-3-methylimidazolium and 1-alkyl-2-methyl-3-methylimidazolium liquid salts are also reported.Electrochemical capacitors are energy conversion devices which consist of two active electrode materials that are in contact with an appropriate electrolyte. 1 First, electronically conducting polymers such as polythiophene derivatives, have recently received some attention as electrode materials due to their potentially high power densities which originate from fast redox switching (e.g. fast ionic transport). 2 Second, conventional liquid solvent-salt and polymer-salt were used as electrolyte (to insure ionic conduction between the two polymer electrodes) in these capacitors. 2 Thiophene derivatives are among the most widely investigated model compounds for electrically conducting material since they give rise to polymers which may be both p-and n-type doped. 2-7 Within this family of polymers, poly(cyclopenta[2,1-b:3',4'-b']dithiophen-4-one, (CDT) 5, introduced by Lambert and Ferraris, 8 stands out for its electrochemical properties, high stability in the conducting state and propensity to multiple redox cycling, making it a stable p-and n-dopable conductor suitable for application as supercapacitors composites as we have recently shown. 9 Roncali et al. have also reported that the polymer obtained from the 1,3-dioxolane derivative of the title compound 5 displayed similar electrochemical properties. 10 Since, many of the precursors of small band gap conducting polymers are substituted-4-methylidene derivatives of 5, 4,9-16 ketone 5 is an important intermediate in the synthesis of a variety of low band gap conducting polymers. 17On the other hand, room-temperature ionic liquids have also attracted interest as solvents for synthesis and catalysis applications, which have recently been reviewed. 18 These liquid salts can replace classic organic solvents which may be volatile and/or hazardous. Much of the progress realized to date render these room-temperature molten salts more stable, chemically and thermally. These liquids are entirely composed of ions and in this state, they resemble the ionic melts which are generally produced by heating normal metallic salts such as sodium chloride to high temperature (e.g. NaCl to over 800°C). Some other useful features of these ionic liquid systems include the greater solubilities of organic species, the prevalence of high coulombic forces resulting in the absence of any significant vapor pressure and the availability of air and moisture stable, water immiscible ionic liquids (e.g. imidazolium salts of PF 6 -or BF 4 -). Such systems are able media for the development of completely nove...

Several arylthiophene derivatives were synthesized using the Kumada cross-coupling reaction and electropolymerized at a platinum electrode with the aim of investigating the effect of the number of thiophene unit and substitution pattern of the monomers on the spectroscopic and charge storage properties of the resulting polymers. The electrochemical oxidation of these monomers showed a decrease of the anodic peak potential as the number of thiophene units is increased: 1.2−1.4, 1.0, and 0.75 V for the mono-, bi-, and terthiophene, respectively. The polymers having one phenyl ring per thiophene unit displayed a larger band gap with the exception of poly-3-phenyl-thiophene, which showed a much smaller band gap. The lower band gap for the later can be explained by the higher reactivity of the cation radical (as evidenced by a high oxidation potential) which led to a highly conjugated polymer. The cyclic voltammograms of the same polythiophene derivatives is characterized by a significant charge unbalance between the doping and undoping charge and most showed a limited cycle lifetime. On the other hand, poly-3-phenyl thiophene, poly-3‘-(1-naphthyl)-2,2‘:5‘,2‘ ‘-terthiophene are the more stable and also show a relatively good balance between doping and undoping charge for both the p- and n-doping redox processes. The highest voltammetric charge density evaluated by considering the weight of monomer unit was recorded for poly-3-phenyl thiophene despite the fact that some poly terthiophene derivatives have a lower phenyl ring/thiophene unit ratio.

Lignin availability has increased significantly due to the commercialization of several processes for recovery and further development of alternatives for integration into Kraft pulp mills. Also, progress in lignin characterization, understanding of its chemistry as well as processing methods have resulted in the identification of novel lignin-based products and potential derivatives, which can serve as building block chemicals. However, all these have not led to the successful commercialization of lignin-based chemicals and materials. This is because most analyses and characterizations focus only on the technical suitability and quantify only the composition, functional groups present, size and morphology. Optical properties, such as the colour, which influences the uptake by users for diverse applications, are neither taken into consideration nor analysed. This paper investigates the quantification of lignin optical properties and how they can be influenced by process operating conditions. Lignin extraction conditions were also successfully correlated to the powder colour. About 120 lignin samples were collected and the variability of their colours quantified with the CIE L*a*b* colour space. In addition, a robust and reproducible colour measurement method was developed. This work lays the foundation for identifying chromophore molecules in lignin, as a step towards correlating the colour to the functional groups and the purity.

New insights on the variability of solubility elucidated for diverse lignins, quantification thereby makes it possible to predict performance for solvent fractionation processes and polymers formulation.

Yellow birch barks is one of the abundant species in Quebec with harvest surplus in several regions. Biofuels or biochemicals such as biobutanol can be produced using the surplus feedstock, however challenges such as the cost of pretreatment, production of unwanted by-products in the fermentation process, and the efficient recovery of solvents must be addressed to make it feasible. The objectives of this study are to establish the optimal conditions to produce biobutanol from Eastern Canadian yellow birch; to identify natural/local Clostridium sp. strains that are capable of producing Isopropanol-Butanol-Ethanol (IBE) from synthetic sugar mixtures, as candidates for metabolic engineering and to benchmark solvent producing ability with commercially available strains; and to elucidate the challenges of paradigm shift to IBE production. Alkali pretreatment of the biomass using chemical that are present in the Kraft process were performed, followed by enzymatic hydrolysis to obtain fermentable sugars and subsequent fermentation with Clostridium acetobutylicum DSM 792. The results showed that the produced Acetone-Butanol-Ethanol (ABE) solvent concentration were 6.6-8.2 g/L of acetone; 11.2-13.1 g/L of butanol; and 2.5-2.7 g/L of ethanol. The organic acids concentration was acetic acid, 1.1-1.8 g/L, and butyric acid, 0.1-0.2 g/L. Further fermentation experiments to benchmark IBE were performed using both Clostridium beijerinckii DSM 6423 and wild isolated strains, which revealed the gaps in terms of yields and the need to optimize the fermentation paradigm. Moreover, alternative process sequences for product recovery were identified, and the impact of prior liquid-liquid extraction elucidated.