The kinetics of oxiranes addition to bis/2-hydroxyalkyl/disulfides and bis/2-hydroxyalkyl/sulfides in the presence of N,N-dimethylcyclohexylamine

Rate constants for the reaction of oxiranes with bis/2-hydroxyalkyl/disulfides, bis/2-Hydroxyalkyl/sulfides, and 1,6-Hexanediol in the presence of N,N-dimethylcyclohexylamine were studied at the temperature range of 50–90°C. A mechanism of these reactions has been proposed and its kinetic equation has been presented.     

Mass spectra of perfluoroalkyl and perfluoroalkylether nitriles and acyl halides

Electron impact fragmentation patterns were obtained for perfluoroalkylether nitriles, C,F,O[CF(CF₃)CFIO]ICF(CF₃)CN (x = 1 and 2), perfluoroalkylether acyl halides, CSF,OCF(CF,)-CF₂OCF(CF₃)COX (X = F and Cl), n-perfluorooctanonitrile and n-perfiuorooctanoyl chloride. The perfluoroalkyl and perfluoroalkylether nitriles afforded ions characteristic of the nitrile function. The major fragment from the acyl chlorides was the [COClJ]+ ion; the presence of chlorine was evidenced also by rearrangement ions of the general form [R_fCl] t. The perfluoroalkylether compounds appeared to undergo a typical fragmentation governed by the cleavage of the carbon-oxygen bond.     

Ion-Molecule reactions in methylamine and dimethylamine and trimethylamine systems

Fourier transform ion cyclotron resonance mass spectrometry has been used to measure the reaction rates for ions derived from methylamine with dimethylamine or trimethylamine. The use of the selective ion ejection technique greatly simplifies the elucidation of the ion-molecule reaction channels. The rate constants for proton transfer from protonated metwlamine, CH₃NH ₃ ⁺ (m/z 32), to dimethylamine and trimethylamine are 16.1 ± 1.6 × 10^?10 and 9.3 ± 0.9 × 10^?10 cm³ molec^?1s^?1, respectively. The rate constants for charge transfer from methylamine molecular ion, CH₃NH ₂ ⁺ (m/z 31), to dimethylamine and trimethylamine are 9.3 ± 1.8 x 10^?10 and 15.0 ± 5 × 10^?10 cm³molec^?1s^?1, respectively.     

Adsorption of oligooxypropylenated amines at the aqueous solution—air interface: Homologous series of piperidine and morpholine derivatives

The surface tension isotherms for pure oligooxypropylenated piperidine and morpholine at the aqueous solution—air interface were determined and interpreted. The surface excess concentration, Γ, the surface area per molecule, A, and the standard free energy of adsorption, ΔG°, were calculated according to a new empirical adsorption equation. The standard free energy contribution for the oxypropylene group (PO) in morpholine derivatives,ΔG° (PO) = −3.34 kJ mol⁻¹, is substantially lower than that for the PO group located in the piperidine derivatives, i.e. ΔG° (PO)= −3.12 kJ mol⁻¹.     

Surface-active, micellar, and antielectrostatic properties of bis-ammonium salts

A series of new cationic surfactants, bis-quaternary ammonium dibromides, were synthesized. The properties of these surfactants were characterized by surface tension measurements, conductivity study, and dynamic light scattering. The surface properties, such as surface excess concentration, Gamma(cmc), surface area demand per molecule, A(min), efficiency in surface tension reduction, pC(20), the effectiveness of surface tension reduction, gamma(min), critical micelle concentration, cmc, and standard free energy of micellization, DeltaG(mic)(0) and DeltaG(ads)(0), were obtained by means of surface tension measurements. The antielectrostatic properties were investigated by measuring the surface resistance, the half-charge decay time, and the maximum voltage induced on polyethylene films and propylene unwoven fabrics. Critical micellar concentrations (cmc) of investigated salts were much lower than those of the monomeric salt DTAC. The results obtained in this work were compared to analogous bis-quaternary ammonium dichlorides and well-known gemini cationic surfactants. It was found that the type of counterion had an impact on the values of the micelle ionization degree and the hydrodynamic diameters. Larger aggregates were found for bis-quaternary ammonium dibromides, which had smaller values of the ionization micelle degree than bis-quaternary ammonium dichlorides. Moreover, the antielectrostatic effect strongly depended on the kind of counterion. All investigated salts had very good antistatic properties.     

Formulation of Environmentally Safe Graffiti Remover Containing Esterified Plant Oils and Sugar Surfactant

The removal of graffiti or over-painting requires special attention in order to not induce the surface destruction but to also address all of the important eco-compatibility concerns. Because of the necessity to avoid the use of volatile and toxic petroleum-based solvents that are common in cleaning formulations, much attention has recently been paid to the design of a variety of sustainable formulations that are based on biodegradable raw materials. In the present contribution we propose a new approach to graffiti cleaning formulations that are composed of newly synthesized green solvents such as esterified plant oils, i.e., rapeseed oil (RO), sunflower oil (SO), or used cooking oil (UCO), ethyl lactate (EL), and alkylpolyglucosides (APGs) as surfactants. Oil PEG-8 ester solvents were synthesized through the direct esterification/transesterification of these oils using monobutyltin(IV) tris(2-ethylhexanoate) and titanium(IV) butoxide catalysts under mild process conditions. The most efficient formulations, determined by optimization through the response surface methodology (RSM) was more effective in comparison to the reference solvents such as the so-called Nitro solvent (denoting a mixture of toluene and acetone) and petroleum ether. Additionally, the optimal product was found to be effective in removing graffiti from glass, metal, or sandstone surfaces under open-field conditions in the city of Wrocław. The performed studies could be an invaluable tool for developing future green formulations for graffiti removal.     

Characterization of the Microenvironments of Alkylamidoamine-N-oxide Surfactant Aggregates by the EPR Spin Labeling Method

Spin labeling EPR methods were applied to characterize the local microviscosity and micropolarity of micellar aggregates formed by 3-(alkanoylamino)ethyldimethylamine-N-oxides (alkyl = nonyl, undecyl and tridecyl) in an aqueous environment in the temperature range 297?C337?K. Four doxylstearic derivatives: 5-doxylstearate methyl ester (5-DSE), 16-doxylstearate methyl ester (16-DSE), 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA) were used as spin probes to monitor mainly the rotational correlation time ?? _R and the isotropic hyperfine splitting constant A _N. In the case of anisotropic spectra, the order parameter S was also determined. The selected probes were found to be sensitive to the microenvironments whereby it was possible to characterize in detail local changes in composition and micelle formation.     

O-Trimethylsilylenol ethers as versatile building blocks in a modular preparation of polyenic backbone

Versatility and synthetic potential of 1-(trimethylsilyloxy)-1,3-butadiene, 1-(trimethylsilyloxy)penta-1,3-diene, and their methyl substituted derivatives have been demonstrated in a modular synthetic methodology of stereodefined π-conjugated unsymmetrical, symmetrical two-dimensional, and octupolar polyenal structure.     

Potentiometrische Titrationen in der L?sung vom Triacetatsolvat des Trimethylaminacetats

Zusammenfassung Es wird über die physikalischen Eigenschaften und den chemischen Charakter des Triacetatsolvats des Trimethylaminacetats berichtet sowie über die Möglichkeit, diese Verbindung als wasserfreies Lösungsmittel anzuwenden. Viele anorganische und organische Verbindungen sind in TAT löslich. Die untersuchten potentiometrischen Fällungs- und Redoxtitrationen in TAT ergeben potentiometrische Kurven von normalem Verlauf und guter Reproduzierbarkeit.     

Influence of N-hexadecyl-N,N,N-trimethylammonium nitrate on the dehydrobromination reaction of 2-phenylethyl derivatives

The basis dehydrobromination of p-substituted 2-phenylethyl bromides promoted by hydroxide ion has been studied in micelles of N-hexadecyl-N,N,N-trimethylammonium nitrate (CTANO₃). The pseudophase ion exchange model can be adapted to explain the kinetic results at low hydroxide ion concentration, i.e., less than 0.075 M of NaOH. At high hydroxide ion concentration in solution the applied model does not describe the kinetic results unless the empirical variations are applied for the mol ratio of reactive ion to micellar head group (β) and the binding constant of the organic reagent to the micelle (K_s).