The reactions of pyridinyl and alkylpyridinyl radicals with duroquinone involve an electron transfer to produce the durosemiquinone radical in a diffusion-controlled process. The rate constants for such reactions in several ionic liquids and molecular organic solvents are determined by pulse radiolysis. The ionic liquids used are N-butylpyridinium tetrafluoroborate (BuPyBF 4 ) and the following tetraalkylammonium (R 4 N + ) salts of bis-(trifluoromethylsulfonyl)imide ( -NTf 2 ): methyltributylammonium (MeBu 3 NNTf 2 ), hexyltributylammonium (HxBu 3 NNTf 2 ), methyltrioctylammonium (MeOc 3 NNTf 2 ), and methylbutylpyrrolidinium (MeBuPyrNTf 2 ). The molecular solvents used are triethanolamine (TEOA) and cyclohexanol (c-HxOH). The experimental rate constants in the molecular solvents are only slightly higher than the diffusion-controlled rate constants estimated from the viscosity. On the other hand, the experimental values in the ionic liquids are about an order of magnitude higher than the values estimated from the measured viscosity. The reason for this difference is suggested to be due to the voids that exist in ionic liquids and the possibility that diffusion of reacting species takes place through movement of segments of the ions while the viscosity is related to movement of the whole ions.

Novel trigeminal tricationic ionic liquids (TTILs) have been successfully synthesized in high yields by means of Menschutkin quaternization via an S(N)1 mechanism. This reaction presents a new convenient method for transforming glycerol into multifunctional compounds. The physical properties of a series of TTILs were characterized by using a variety of techniques. The prepared salts were tested for antimicrobial activity. Electrochemical characterization of TTILs was also performed, which allowed the estimation of the conductivity of these new compounds, to establish their electrochemical stability window and capacitance properties over a wide range of temperatures. A good correlation of the physical properties of TTILs with capacitance values was observed.

No abstract

The rate constant for the Menschutkin reaction of 1,2-dimethylimidazole with benzyl bromide to produce 3-benzyl-1,2-dimethylimidazolium bromide was determined in a number of ionic liquids and molecular organic solvents. The rate constants in 12 ionic liquids are in the range of (1.0-3.2) × 10 −3 L mol −1 s −1 and vary with the solvent anion in the order (CF 3 SO 2 ) 2 N − < PF 6 − < BF 4 − . Variations with the solvent cation (butylmethylimidazolium, octylmethylimidazolium, butyldimethylimidazolium, octyldimethylimidazolium, butylmethylpyrrolidinium, and hexyltributylammonium) are minimal. The rate constants in the ionic liquids are comparable to those in polar aprotic molecular solvents (acetonitrile, propylene carbonate) but much higher than those in weakly polar organic solvents and in alcohols. Correlation of the rate constants with the solvatochromic parameter E T (30) is reasonable within each group of similar solvents but very poor when all the solvents are correlated together. Better correlation is obtained for the organic solvents by using a combination of two parameters, π * (dipolarity/polarizibility) and α (hydrogen bond acidity), while additional parameters such as δ (cohesive energy density) do not provide any further improvement. C

Effects of chemical modification of wood with innovative ionic liquid on the supermolecular and morphology of wood/polypropylene composites were investigated using X-ray diffraction, hot stage optical microscopy, and differential scanning calorimetry. For the first time the chemical treatment of wood was conducted solely with newly synthesized ionic liquid, didecyldimethylammonium bis(trifluoromethylsulfonyl)imide. The modification was found to be responsible for significant changes in nucleating abilities of wood in polypropylene matrix. These findings were confirmed by crystallization temperature, crystal conversion, crystallization half-time parameters, as well as observation of transcrystalline structures. Ionic liquid treatment of wood influenced also formation of polymorphic forms of polymer matrix. In contrast to composites with untreated wood, in composites with modified wood filler formation of b-phase of polypropylene was observed. This fact was discussed in view of differences in nucleating activity of lignocellulosic filler, resulting from chemical treatment with ionic liquid. Moreover, a relationship between mechanical properties of composites and the phenomena taking place at the polymer-filler interface, controlled by chemical modifications of lignocellulosic components, was evaluated.

A series of 70 new 3,3'(α,ω-dioxaalkyl)bis(1-alkylimidazolium) chlorides were synthesized. They were characterized with respect to surface active properties and antimicrobial activity against the following pathogens: Staphylococcus aureus, Enterococcus faecalis, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Candida krusei, and Candida albicans. In this article, besides description of the synthesis, we characterize a set of features of these compounds, concerning their structure (described by the length of the dioxaalkan spacer and the length of the alkyl substituent in the aromatic ring) and surface active properties (critical micelle concentration, value of surface tension at critical micelle concentration, value of surface excess, molecular area of a single particle, and free energy of adsorption of molecule). Then, we present a SAR study for Staphylococcus aureus, as one of the most widespread pathogenic strains, conducted with the help of the Dominance-based Rough Set Approach (DRSA), that involves identification of relevant features and relevant combinations of features being in strong relationship with a high antimicrobial activity of the compounds. The SAR study shows, moreover, that the antimicrobial activity is dependent on the type of substituents and their position at the chloride moiety, as well as on the surface active properties of the compounds.

No abstract

The aggregation behavior in the transition region was studied for a series of dicationic surfactants 3,3′-[α,ω-(dioxaalkane)]bis(1-dodecylimidazolium)dichlorides with varied spacer length from two to twelve carbon atoms.