L. E. Shmukler

Bio: L. E. Shmukler is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Ionic liquid & Triethanolamine. The author has an hindex of 9, co-authored 25 publications receiving 212 citations.

Thermal behavior and electrochemistry of protic ionic liquids based on triethylamine with different acids

Abstract: Protic ionic liquids (PILs) composed of the triethylammonium cation with dihydrogen phosphite, tosylate, and trifluoroacetate anions were synthesized. All samples were salts with melting points below 100 °C and were characterized via NMR spectroscopy, attenuated total reflection (ATR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry (TG). The electrochemical characteristics of each protic ionic liquid were obtained using a combination of impedance spectroscopy and cyclic voltammetry. Moreover, the influence of water on the thermal behavior and conductivity of triethylammonium tosylate is studied. A linear correlation between the temperatures of melting and crystallization is established for a number of PILs, including both derivatives of triethylamine with different acids reported in the literature and the newly synthesized PILs. The optimal combination of thermal characteristics and electroconductivity was observed for triethylammonium trifluoroacetate and tosylate.

Conductance studies of 1-1 electrolytes in N,N-dimethylformamide at various temperatures

Abstract: Conductance data for NaNO3, KI, Pr4NBr and Bu4NI in N,N-dimethylformamide (DMF) at − 40, − 35, − 25, − 15, − 5, 5, 15, 25, 35 and 45°C are reported. The data have been analysed by the Lee–Wheaton conductance equation in terms of the limiting molar conductance (Λ0) and association constant (KA). Evaluation of single ionic conductances has been carried out on these data and on preceding experimental conductance data for MBr (M = Na+, K+, Cs+, NH4+, Et4N+, Pr4N+, Ph4P+), KClO4, NaBPh4 , Ph4PCl and Bu4NBPh4 using the Walden product of Bu4N+. The temperature dependences of Λ0 and KA are discussed. The values of KA indicate that all these salts are weakly associated in DMF.

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ionic Liquid–Polymer Composites: A New Platform for Multifunctional Applications

Abstract: The authors thank the FCT (Fundacao para a Ciencia e Tecnologia) for financial support under the framework of the Strategic Funding UID/FIS/04650/2019 and projects PTDC/BTMMAT/28237/2017, PTDC/EMD-EMD/28159/2017 and PTDC/FIS-MAC/28157/2017. Funds provided by FCT in the framework of EuroNanoMed 2016 call, Project LungChek ENMed/0049/2016 are also gratefully acknowledged. D.M.C, L.C.F and C.M.C also thanks to the FCT for the grants SFRH/BPD/121526/2016, SFRH/BD/145345/2019 and SFRH/BPD/112547/2015, respectively. PMM thanks to the ENMed_CQ_CF_04_2018 grant. Finally, the authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively.

Plant Nanomaterials and Inspiration from Nature: Water Interactions and Hierarchically Structured Hydrogels

Abstract: Recent developments in the area of plant-based hydrogels are introduced, especially those derived from wood as a widely available, multiscale, and hierarchical source of nanomaterials, as well as other cell wall elements. With water being fundamental in a hydrogel, water interactions, hydration, and swelling, all critically important in designing, processing, and achieving the desired properties of sustainable and functional hydrogels, are highlighted. A plant, by itself, is a form of a hydrogel, at least at given states of development, and for this reason phenomena such as fluid transport, diffusion, capillarity, and ionic effects are examined. These aspects are highly relevant not only to plants, especially lignified tissues, but also to the porous structures produced after removal of water (foams, sponges, cryogels, xerogels, and aerogels). Thus, a useful source of critical and comprehensive information is provided regarding the synthesis of hydrogels from plant materials (and especially wood nanostructures), and about the role of water, not only for processing but for developing hydrogel properties and uses.

Prediction of mineral scale formation in wet gas condensate pipelines and in meg (mono ethylene glycol) regeneration plants

Abstract: Gas hydrate formation is a serious problem in the oil and gas industry, since its formation can plug wells and prevent production. The gas hydrate is a crystalline solid with a natural gas molecule surrounded by a cage of water molecules. It forms at high pressures and low temperatures. This is a problem for offshore gas wells, where the temperature is low in transport lines from well to the production facilities. Mono Ethylene Glycol (MEG) is commonly used as hydrate inhibitor. Classified as a thermodynamic inhibitor, this additive functions just as antifreeze in an automotive radiator.When producing oil and gas there will in most cases also be produced some water, which can contain dissolved salts. These salts may precipitate and they tend to deposit on surfaces. Deposition of inorganic minerals from brine is called scale.Generally MEG has the adverse effect of lowering the solubility of most salts. A common method to prevent corrosion in flowlines is to increase pH by adding basic agents (e.g. NaOH, NaHCO3) to the MEG stream. In such cases, carbonate salts are particularly troublesome since an increase in pH by one unit, will reduce the solubility by two orders of magnitude. Thus there will be a trade off between good corrosion protection (high pH) and scale control (low pH).The aim of this work has been to develop a model that can predict mineral solubility in the presence of MEG. Experimental solubility data, together with thermodynamic data taken from literature, have been utilized to construct empirical functions for the influence of MEG on mineral scale formation. These functions enabled the expansion of an already existing aqueous scale model into a model valid for water+MEG mixed solutions. The aqueous scale model combines an equation of state (gas+oil phase) with the Pitzer ion interaction model (water phase) to describe the multiphase behaviour of gas-oil-water systems. This work describes how MEG has been introduced into the water phase model.The general idea is that the activity of a specie, ί, is given as its concentration, m, times the activity coefficient, γ , which is divided in two parts. γS shall take care of the “Salt effects”, and γN the “MEG effects”;ai=miγi=miγs iγNiγS is calculated by the Pitzer model, as if the solvent was water, and consequently has the same numerical value regardless of the MEG concentration in the water+MEG solvent. γN is empirically fitted from solubility data and is obviously a function of MEG concentration. γN may also be dependent on temperature and ionic strength.The pressure dependence of γN has not been investigated in this work. All equilibrium constants, K°, are independent of MEG concentration. Theoretically this corresponds to a pure water standard state. This modelling approach has the advantage that it gives a simple and robust model with reasonable extrapolations outside the range of experimental data. Practically it turns out that the effects of temperature, and that of dissolved species (ionic strength) are almost the same in water+MEG solutions as in water. In such a case a good approximation will be to let the γN term merely be dependent on MEG concentration. It has been shown that γN for some systems is a function of both temperature and ionic strength in addition to MEG concentration. The mathematical functions used for curve fitting γN were generally arbitrarily chosen polynomials, meaning that they do not have any physical/theoretical basis.The resulting model has good flexibility and can do exactly the same type of calculations as the aqueous model. It can handle MEG concentrations of up to 99 weight % in the solvent. MEG concentration is commonly specified in the water phase, but the model also accepts MEG input in the gas or oil phase. For conditions encountered in oil and gas transport pipelines and at well heads, the model should function well. It is empirically fitted from solubility data, generally covering the range 0-100°C and 0-100% MEG in the solvent. Hence if the model predicts precipitation of a salt, the ionic strength is normally comparable with the value in the data used for fitting the model. In e.g. a MEG regeneration boiler, however, the temperature is high, and/or several highly soluble species like Na+, K+, CO32-, Cl- are present yielding a very high salinity. The model is therefore not suited for calculations at such conditions.MEG influences the phase distribution of gases. This effect has been included for CO2, H2S, CH4 and the most common organic acids found in the oilfield. CO2, H2S, and the organic acids also have MEG dependent dissociation equilibria.The scale forming minerals included in the model are:→ CaSO4, CaSO4·2H2O, BaSO4 and SrSO4→ CaCO3, FeCO3, BaCO3, SrCO3, and 3MgCO3·Mg(OH)2 ·3H2O→ NaCl and KCl→ NaHCO3 and KHCO3,→ NaAc and NaAc·3H2O→ Na2CO3, Na2CO3·H2O and Na2CO3·10H2O→ K2CO3 and K2CO3·1.5H2O→ FeS→ Mg(OH)2,Much new data have been gathered for the water+MEG system, mainly concerning the first dissociation constant of CO2, the solubilities of the carbonates; CaCO3, BaCO3, SrCO3 and 3MgCO3·Mg(OH)2·3H2O as well as the sulphates, CaSO4 and CaSO4·2H2O. These experiments were confined to 20-80°C and ionic strengths of 0-0.7mol/kg.Hydromagnesite (3MgCO3·Mg(OH)2·3H2O) has been included as the only magnesium carbonate mineral in the scale model. Hydromagnesite is actually a meta-stable phase, but the thermodynamically stable magnesite (MgCO3) has been omitted due to its formation being kinetically inhibited. Magnesite of sufficient purity for solubility investigations was not available from commercial suppliers. It was therefore necessary to synthesize it in the laboratory. A new method for synthesizing magnesite from hydromagnesite at atmospheric conditions has been suggested. Mono Ethylene Glycol(MEG) is used to lower the solvent vapour pressure at temperatures above 100°C.The MEG concentration of an unknown sample is often measured using Gas chromatography (GC). This is an accurate method but has the disadvantage that the sample very often has to be shipped to an external laboratory. A new method for prediction of MEG concentration that is fast, easy and inexpensive has been developed. Values of density, conductivity and alkalinity of an aqueous solution, are used to estimate both MEG and salt contents. The method is valid in the whole concentration interval of 0 to 100 wt% MEG and with ionic strengths from zero to the solubility limits of NaCl and NaHCO3. At intermediate MEG concentrations (40 to 90wt %) the accuracy is regarded as ±2 wt % for MEG content determination. The main limitation is that NaCl and/or NaHCO3 must be the dominating dissolved salts.pH is an important parameter in carbonate scale prediction. This work summarizes the theoretical foundation and proposes how to work with pH in water+MEG solutions. A pH electrode calibrated only in common aqueous standard solutions, gives a measured value denoted pHmeas in this work. pHmeas is not reproducible in water+MEG solutions. Calibration also in 0.05m KHPh (Potassium Hydrogen Phtalate) solutions with certain MEG concentrations, gives the calibration value; ΔpHMEG. The actual pH, which is reproducible, can thereafter be found from pHmeas as;pH = pHmeas + ΔpH MEG+ ΔpHSaltΔpHMEG has to be determined once for each electrode. ΔpHSalt adjusts for the salt/ionic strength impact on the electrode and is only important at ionic strengths above ~0.5mol/kg.