Production cost can be reduced in preparation of powdered activated coke (PAC) by achieving higher SO2 adsorption capacity and lower burn-off. In this study, for the rapid preparation of PAC from pulverized coal, response surface methodology (RSM) based on central composite design (CCD) was used to develop the second order quadratic models of SO2 adsorption capacity and burn-off. Analysis of variance (ANOVA) was used to determine the effective parameters of the two models, and to explain the accuracy and fitness of them. In addition, the 3D response surface plots illustrated the influencing rules of the variables and their interactions. Further, multi-objective optimization was performed to maximize SO2 adsorption capacity and minimize burn-off using the desirability function. Optimal process parameters obtained were: reaction temperature, 923.97℃; oxygen concentration, 5.89% and vapor concentration, 20.04%; and the corresponding prediction results were: SO2 adsorption capacity, 110.31mg/g; burn-off, 47.45%. Confirmation experiment at the optimal condition was carried out, and the experimental results were consistent with the model prediction results, further verifying the accuracy and fitness of the models. The optimization results would provide guidance for the design and operation adjustment of large-scale industrial applications in the future.

X-ray scattering measurements were utilized to probe the effects of doping the neat 1-methyl-3-octylimidazolium bis (trifluoromethylsulfonyl) imide [C8mim][TFSI] room temperature ionic liquid with alkali-TFSI salts of varying concentrations. The introduction of lithium TFSI, sodium TFSI, potassium TFSI, rubidium TFSI and cesium TFSI has the universal effect on the scattering intensity of depressing the charge alternation peak and enhancing the aggregation peak as the relative concentration is increased. The changes in the liquid structure are interpreted as a result of the formation of long-lived alkali-TFSI complexes. The depression of the charge alternation peak is due to a more disordered structure at that length scale as the doping concentration increases. The aggregation peak is demonstrated to increase in height for all alkali complexes due to an increase in the scattering strength of the complexes and an increase in their prevalence as the concentration of each alkali salt is increased.

By a comparative study of the concentration-dependent IR spectra of methyl benzoate (MB)/methanol-d4 and MB/n-hexane mixtures, it is found that the infrared wavenumber (υ˜) of ester group (OCO) of MB in the former system decreased exponentially with the increase of mole fraction of MB (x1), while that of the latter system decreased linearly, suggesting that H-bonding interaction plays an important role in the microstructure of MB/methanol-d4 mixture. Therefore, to explore the microstructure and characterize the strength of H-bonding interaction of MB/methanol mixture, the excess infrared wavenumber of a group (υ~groupE) is proposed, showing that υ~O−DE of methanol-d4 presents an S shape with a minimum value at x1 ≈ 0.4 and a maximum value at x1 ≈ 0.8, respectively. Furthermore, the absolute value of υ~O−DE (|υ~O−DE|) of the former is greater than that of the latter, suggesting that H-bonding interaction in methanol-d4 molecules is stronger than that between methanol-d4 and MB. While both υ~C=OE and υ~C−OE of MB show a negative deviation with minimum values at x1 ≈ 0.4, and |υ~C=OE| is larger than |υ~C−OE|, indicating that CO is directly involved in H-bonding interaction with OD, resulting in the change of υ~C−OE through the electronic conjugation effect. To confirm the microstructure obtained from IR spectra, densities, speeds of sound, and viscosities of MB/methanol mixture are measured and excess properties are calculated. The results show that both excess molar volumes and isentropic compressibility deviations have a negative deviation with a minimum value at x1 ≈ 0.4, which is good consistent with x1 corresponding to the minimum value of υ~O−DE, υ~C=OE, and υ~C−OE, respectively. Moreover, viscosity deviations exhibit a negative deviation with a minimum value at x1 ≈ 0.8, which is good consistent with x1 corresponding to the maximum value of υ~O−DE.

In present study, a tetra-functionalized aromatic epoxy pre-polymer namely, 4,4′-oxybis(N,N-bis(oxiran-2-ylmethyl)aniline) (AA2) was synthesized and established as corrosion inhibitor for carbon steel corrosion in 1 M HCl medium. The prepolymer was characterized by proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FT-IR) spectral techniques and its inhibition property was demonstrated using electrochemical open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), surface scanning electron microscopy (SEM) analysis coupled with energy dispersive spectroscopy (EDS) analysis and computational density functional theory (DFT) and molecular dynamic (MD) simulations methods. Electrochemical studies demonstrate that AA2 acts as sensibly good inhibitor for carbon steel in 1 M HCl medium and showed highest efficiency of as high as 91.3% at 10−3 M. The PDP results show that AA2 behaves as predominantly cathodic type of inhibitor. SEM analysis coupled with EDS showed that AA2 forms surface protective films and isolates the metal from aggressive solution. DFT studies suggest that both neutral as well as cationic forms of the AA2 strongly interact with metallic surface using two aromatic and four oxirane rings. Molecular dynamic simulations (MDS) study showed that AA2 adsorb strongly on metallic surface using their electron rich centers and acquires the parallel or flat orientation. Outcomes of the experimental (SEM-EDS, OCP, EIS and PDP) and computational (DFT and MDS) studies were in excellent concurrence.

We employed non–equilibrium molecular dynamics simulations to investigate the hydrogen–bond dynamics in bulk water upon microwave heating. Microwave irradiation has been taken into account implicitly by performing simulations at a rotational temperature exceeding the translational one (Tr > Tt). We have shown that the effect of an increased Tr results in a modified geometry of the average path for hydrogen–bond switch and in decreased characteristic decay times for the reorientation of a water molecule. We also confirmed the validity of the extended jump model to describe hydrogen–bond dynamics under the studied non–equilibrium conditions.

The viscosities (η) of 2-ethylhexan-1-amine (EHA), diglyme, triglyme, tetraglyme and EHA-diglyme/triglyme/tetraglyme non-aqueous solutions were measured by using the NDJ-5S rotational viscometer at 101 kPa. The temperatures (T) ranged from 303.2 K to 323.2 K. The mass fractions of EHA (wEHA) ranged from 0.100 to 0.900. The viscosity was modeled and the calculated results agreed well with the experiments. The effects of wEHA and T on viscosity were demonstrated on the basis of experiments and calculations. The initial absorption rates of CO2 (r) in EHA-diglyme/triglyme/tetraglyme non-aqueous solutions were measured, and the effects of viscosity, absorbent concentration and absorption rate constant of CO2 (k) on initial absorption rates were demonstrated. Our research shows that in the temperature range of 303.2 K to 323.2 K, the proposed three non-aqueous absorbents have small solution viscosities (<3 mPa·s), which is beneficial to the mass transfer of CO2 absorption and the initial absorption rate. Thus the proposed non-aqueous absorbents have good application potential in the field of CO2 capture process.

The influence of Pluronics L64, F68, F88 and F127 on the solubility and membrane permeability of leflunomide (LEF) in acidic and alkaline buffer solutions with physiological pHs was revealed. A noticeable increase of LEF solubility in the presence of Pluronics was revealed. It was demonstrated that the structure of Pluronics has influence on the manifestation of a solubilizing effect. Namely, more efficient solubilizers for LEF were found to be L64 and F127, having the lowest content of ethylene oxide groups in the structure and lower HLB indices in comparison with F68 and F88. The binding of LEF with the core of Pluronic micelles was proposed on the basis of the obtained 1Н NMR data. Permeability of LEF through an artificial Permeapad barrier composed of phospholipids was measured using the Franz diffusion cell. Decrease of the LEF permeability in the presence of all investigated Pluronics was detected. The location of hydrophobic fragment of LEF molecule inside the micelle leads to a decrease in the non-polar surface area and the ability of the drug to pass through the lipophilic layer of the membrane.

The solvation properties of Co3+ and Ir3+ in pure liquid ammonia have been investigated via ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulations. During the simulation time of 20 ps, octahedral [Co(NH3)6]3+ and [Ir(NH3)6]3+ complexes were formed in the first solvation shell without the occurance of ligand exchange. The respective average first shell ion distance of Co3+ and Ir3+ were found to be 2.07 and 2.18 Å, respectively. The solvation properties in the first shells of each system are found in excellent agreement with experimental data. A number of ligands were exchanged between the second solvation shell and the bulk phase in both systems along the simulation. The associated mean residence times of NH3 ligands in the second shell are 3.06 and 2.47 ps for Co3+ and Ir3+, respectively.

In this research article, we have investigated the dielectric properties of a nematic liquid crystal (NLC), namely 4 cyano-4′- pentylbiphenyl (which is commonly known as 5CB), in sample cells of variable thickness. The dielectric behaviour has been studied through a LCR meter in the frequency ranging from 20 Hz to 1 MHz. It was observed that the real part of complex dielectric permittivity (ε') decreases and the peak value of the energy dissipated per unit cycle (ε'′) increases on increasing the cell thickness. It has also been noticed that the relaxation frequency of LC material under investigation shifts towards the lower side with the increment in the sample cell thickness. The observed dielectric behaviour has been attributed to the contribution of the ionic species available in the NLC used. The mobilized ions have a significant contribution in influencing the dielectric studies of 5CB in thin cells. Further, all the above mentioned physical attributes of 5CB will play an important role in fabricating a device which is not only cost effective but also has higher transmittance and negligible power consumption.

The protonation of the carboxamide nitrogen atom is an essential part of in vivo and in vitro processes (cis‐trans isomerization, amides hydrolysis etc). This phenomenon is well studied in geometrically strongly distorted amides, although there is little data concerning the protonation of undistorted amides. In the latter case, the participation of amide nitrogen in hydrogen bonding (which can be regarded as the incipient state of a proton transfer process) is less well‐studied. Thus, it would be a worthy goal to investigate the enthalpy of this interaction. We prepared and investigated a set of peri‐substituted naphthalenes containing the protonated dimethylamino group next to the amide nitrogen atom (“amide proton sponges”), which could serve as models for the study of an intramolecular hydrogen bond with the amide nitrogen atom. X‐Ray analysis, NMR spectra, basicity values as well as quantum chemical calculations revealed the existence of a hydrogen bond with the amide nitrogen, that should be attributed to the borderline between moderate and weak intramolecular hydrogen bonds (2–7 kcal·mol‒1).

Standard molar enthalpies of vaporization/sublimation (check for euro journal) of nitro and amino-substituted benzaldehydes were obtained from the temperature dependence of vapour pressure measured by the transpiration method. Enthalpies of fusion of these compounds were measured by using DSC. Solution enthalpies of nitro and amino-substituted benzaldehydes were measured by using a solution calorimeter. Available from literature primary experimental results on temperature dependences of vapour pressures have been collected and they have been treated uniformly in order to derive vaporization/sublimation enthalpies at the reference temperature 298.15 K. Standard molar enthalpies of formation of crystalline isomers of nitro-benzaldehydes were measured by using combustion calorimetry. Gas phase molar enthalpies of formation of substituted benzaldehydes were calculated by the high-level quantum-chemical G4 method and they were used for evaluation of available experimental results. A set of thermodynamic properties of substituted benzaldehydes was recommended as reliable reference properties for thermochemical calculations. Simple group-additivity procedures were developed for estimation of vaporization enthalpies, gas-phase, and liquid-phase enthalpies of formation of substituted benzenes.

For the obtained high-purity glasses of crystallization-resistant compositions Ge0.25-yGayTe0.75-xIx (y = 0.10, 0.15, x = 0-0.06 mole fractions) by method TM-DSC heat capacity experimentally determined and glass transition characteristics studied. Based on the results of theoretical processing of calorimetric data, standard thermodynamic functions were calculated in the temperature range 0 – 530 K which are complemented by temperature dependences of density and coefficient of thermal expansion. These thermodynamic functions are necessary for determining the conditions of synthesis by minimizing the Gibbs energy of promising representatives of the glass-forming system Ge–Ga–Te–I and prediction of the properties of glasses including those with functional additives that determine their optical-sensory applications.

Amine-based carbon dioxide absorbent has the characteristics of high selective absorption rate and strong absorption capacity and occupies the leading position in the carbon dioxide absorption process. The absorption performance of amine carbon dioxide absorbents is directly related to their thermodynamic properties. Accordingly, for the selection of new absorbents, the important thermodynamic properties such as the excess molar enthalpy of the system must be determined first. In this paper, the excess molar enthalpies for amine-based carbon dioxide absorbents in water were measured with C-80 calorimeter at atmospheric pressure. With the experimental data in this work and the literature data, the relationship between the molecular structure and excess molar enthalpy of amine-based carbon dioxide absorbent was studied.

In a recent publication by Dutta and co-workers in July 2019,(1) the authors reported a vibrational spectroscopic probe of local interactions in imidazolium-based ionic liquids (ILs) by deuteration of the C(2) position of the imidazolium ring. However, while we agree with the value of that approach, the claim that this is a new strategy is quite misleading, as our group has published several studies over the past six years,(2−6) using selective deuteration at the C(2)H position and structural characterization with infrared spectroscopy (more precisely, cryogenic ion vibrational predissociation spectroscopy)(7) to characterize the local microscopic interactions and binding of ILs involving the C(2) position. Our first report in 2013 focused on common imidazolium-based ILs(2−4) and has evolved to include more complicated ILs with functionalized side groups.(5,6) The protocols for H/D exchange(8) in these samples by heating with D2O or CD3OD solvents were described in detail in these studies. In particular, Williams et al. suggested, in the second last paragraph of their manuscript,(1) that a new class of hydroxy-functionalized ionic liquids that display attractive cation–cation interaction(9) could be “potentially detected” with the use of the C(2)D probe. In fact, this had been already done in our collaboration with Prof. Ralf Ludwig on hydroxy-functionalized systems, with our first results(5) in 2018 published in JPC Letters reporting different isomeric structures that were identified for the isolated ternary (HEMIm+)2NTf2– complex [HEMIm+ = 1-(2-hydroxyethyl)-3-methylimidazolium]. The experiment involved deuteration of the imidazolium C(2)H site as well as the OH group on the cation, cooling the ternary clusters to 35 K in a photodissociation mass spectrometer, and application of isomer-selective, two-color IR–IR double resonance spectroscopy. The binding motifs of these structures were identified on the basis of spectral shifts of the C(2)D and OD peaks, which were supported by DFT calculations.(10,11) Since the authors did not refer to any of these papers, we herein wish to correct this oversight. At the same time, we recognize and appreciate the importance of their demonstration that C(2)D substitution is effective in the structural analysis of macroscopic, condensed phase room temperature IL samples. The authors declare no competing financial interest. The authors thank Prof. James F. Wishart for bringing this to our attention. This article references 11 other publications.

We present an in-depth theoretical study of the C(1D) + HD (v=0,j=0) → CD (CH) (v',j') + H (D) reaction using a time-dependent wave packet method with full Coriolis coupling on the Zhang-Ma-Bian potential energy surfaces (PESs) recently constructed by our group. The integral cross sections (ICS), differential cross sections, CD/CH branching ratios, product state distributions are calculated over a wide range of collision energies. We find that the vibrational branching ratio defined as ICS(v'=1)/ICS(v'=0) obtained from the b̃1A" PES is much smaller than that from the ã1A' PES for both product channels, which may be attributed to the dynamical effects of the conical intersection-regulated (CI-R) intermediate on the b̃1A" PES. The collision energy dependence of CD/CH branching ratios displays oscillatory structures, which may be caused by the resonance states supported by the wells on the PESs. The high-temperature rate coefficients are also obtained and compared with the previous results. The role of the excited-state PESs is also discussed.