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Modifiers of the properties of petroleum paving bitumen were developed on the basis of two kinds of acryl-nitrile rubbers BNKSС-18 AM (TU 38.30313-2006) and BNKS-28 AM (TU 38.30313-2006) and the fraction of liquid products of tyre pyrolysis without access of the air, with boiling point above 170 °C. Rubber content in the mixture did not exceed 30 mass %, the temperature of mechanical homogenization was 100-120 °C duration was 3 h. Preliminary studies showed that the mixtures prepared under these conditions do not get separated into phases when kept hot for 6 h. Addition of a modifier in the amount of 3-5 mass % per rubber improves the elasticity of bitumen and, which is especially important, causes a substantial decrease in brittle temperature. Due to this, resistance of paving asphalt concrete to frost and to cracks increases substantially. The composition of the fraction of liquid products of tyre pyrolysis was determined by means of IR spectroscopy and gas chromatography-mass spectrometry. This composition includes more than 100 individual compounds with content >0.1 % of the sum of all detectable peaks. These substances are represented mainly by aromatic hydrocarbons, mainly the derivatives of benzene and naphthalene containing aliphatic fragments with total number of carbon atoms 4 to 10 as substituents (43 rel. %). In addition, hydrocarbons with menthene structure were detected (31 rel. %), and aliphatic acyclic hydrocarbons with chains containing 16 to 27 carbon atoms (18 rel. %). Nitrogen-containing compounds are represented by hexahydro-2Н-azerin-2-one (caprolactam) - 0.5 rel. %, as well as 1,2,3-benzotriazol - 0.9 rel. %.

Results of theoretical studies of the thermal decomposition of substances present in the coke residue from primary coal processing are presented. On the basis of the molecular structure of coke residue represented by 1,3,5-triphenylbenzene, tetraphenylmethane, pentaphenylethane, hexaphenylethane, rubrene and benzoquinoline, the mechanism of thermal decomposition is proposed in the form of generalized chemical reactions. The possibility for reactions to proceed is substantiated by the calculated values of Gibbs energy, determined taking into account thermodynamic parameters of the structural fragments modelling the components of high-carbon coke residue. The changes of enthalpy and entropy of the proposed chemical reactions were calculated. The routes to the formation of the components of generator gas during the interaction of gaseous components with high-carbon substances allowing determination of the kinetic and thermal physical parameters of gasification process are shown.

For medical preparations of antidepressant class (amitriptyline, carbamazepine) as examples, experimental evaluation of the dependence of extraction extent on the parameters of alkaline destruction (concentration of potassium hydroxide, hydrolysis temperature, exposure) and organic solvent used to extract the target substances from hair hydrolyzate was carried out.. Relying on the results of the studies, a universal method of hair sample preparation within chemical toxicological analysis was proposed: hydrolysis of the sample in a 1.5 M KOH solution at 60 °C for 1.5 h, subsequent extraction with a mixture of hexane with ethyl acetate at the volume ratio of 5 : 1. The parameters of gas chromatographic-mass spectrometric detection of the target substances were optimized. A procedure for the analysis of amitriptyline and carbamazepine in hair by means of GC-MS was developed. Validation of this procedure was carried out, the working range of the procedure was determined to be 1-100 ng/mg; detection limits for amitriptyline and carbamazepine were determined to be 0.5 and 1 ng/mg, respectively. This procedure was successfully tested with heal hair samples.

By applying a three-dimensional holographic vector of the atomic interaction field (3D-HoVAIF) to express the structure of three classical peptide drugs, quantitative structure activity relationship (QSAR) models are built by the multiple linear regression. The accuracy of the proposed model is illustrated using (cross-validation) and r ² (test set validation). Moreover, the r _m² metrics is used to further refine the predictive ability of the developed QSAR models. The results show that 3D-HoVAIF, due to the high predictive ability, offers a useful alternative to the costly and time-consuming experiments determining the bioactivity of peptide drugs.

In this work, the molecular geometry of heptachlor is investigated using ab initio HF, DFT, LDA, and GGA methods. The natural bond orbital (NBO) analysis is performed at the B3LYP/6-311++G(d,p) level of theory. The first order hyperpolarizability b_total, the mean polarizability Da, the anisotropy of the polarizability Da, and the dipole moment m, are calculated by B3LYP/6-311++G(d,p) and HF/6-311++G(d,p) methods. The first order hyperpolarizability (b_total) is calculated based on the finite field approach. UV spectral parameters along with HOMO, LUMO energies for heptachlor are determined in vacuum and the solvent phase using HF, DFT, and TD-DFT/B3LYP methods implemented with the 6-311++G(d,p) basis set. Atomic charges and electron density of heptachlor in vacuum and ethanol are calculated using DFT/B3LYP and TD-DFT/B3LYP methods and the 6-311++G(d,p) basis set. In addition, after the frontier molecular orbitals (FMOs), the molecular electrostatic potential (MEP), the electrostatic potential (ESP), the electron density (ED), and the solvent accessible surface of heptachlor are visualized as a results of the B3LYP/6-311++G(d,p) calculation. Densities of states (DOS), the external electric field (EF) effect on the HOMO-LUMO gap, and the dipole moment are investigated by LDA and GGA methods.

DFT calculations are employed to investigate the effects of the addition of a photoisomerizable stilbene unit to Aida's molecular scissors on relative energies, dipole moments, and kinetic stability according to HOMO-LUMO energy gaps and amplitude of the open-close motion of blade moieties. The most obvious finding emerging from this study is the coming into existence of a new pair of molecular scissors operated by two photoswitchable units. Based on photoisomerization of azobenzene and stilbene units, four conformations appear for these new molecular scissors: cis-cis, cis-trans, trans-cis, and trans-trans. The HOMO-LUMO energy gaps promise that all isomers are kinetically stable. The other important finding is that in these new molecular scissors the dihedral angle between the two blade moieties can be controlled and measured through the open-close motion and the blade parts can adopt two middle states in addition to open-close forms.

This paper reports the optimized geometrical parameters of the stationary point for 2,3-bis(furan-2-yl)pyrazino[2,3-f][1,10]phenanthroline. The calculations are performed using the density functional theory (DFT) method at the B3LYP/ LanL2DZ level. Bond lengths and bond angles are determined for the compound and the amount of bond hybridization is calculated according to the natural bond orbital theory (NBO). The energy of frontier orbitals (HOMO and LUMO) are computed. In addition, the calculated data are accurately compared with the experimental results. This comparison shows that our theoretical data are in reasonable agreement with the experimental values.

The torsional potentials, molecular structures, conformational stability, and vibrational wavenumbers for the rotational isomers of 2-formylfuran and 3-formylfuran are computed using the density functional theory (B3LYP) method with the 6-31+G* basis set. All structures are fully optimized and the optimized geometries, rotational constants, dipole moments, and energies are presented. From the computations, both 2-formylfuran and 3-formylfuran are predicted to exist predominantly in trans conformation with a cis-trans rotational barrier of 11.19 kcal/mol and 8.10 kcal/mol, respectively. The vibrational wavenumbers and the corresponding vibrational assignments of the molecules in the C_s symmetry are examined and the infrared spectra of the molecules are simulated using the wavenumbers and the corresponding intensities obtained from the computations. The effect of solvents on the conformational stability of all the molecules in nine different solvents (heptane, chloroform, tetrahydrofuran, dichloroethane, acetone, ethanol, methanol, dimethylsulfoxide, and water) is investigated. The integral equation formalism in the polarizable continuum model (IEF-PCM) is used for all solution phase computations.

The structure, spectroscopic, thermodynamic, and electronic properties of zoledronic acid (ZL,1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-diyldiphosphonic acid), typical third-generation nitrogen-containing bisphosphonates (N-BPs), have been investigated systematically. Six conformations are taken into account, including three unprotonated and three protonated structures. They are optimized by four different density functional theory (DFT) methods combined with four different basis sets to evaluate their performance in predicting the structural and spectral features of ZL. Thermodynamic properties are calculated based on the harmonic vibrational analysis, including the standard heat capacity (C_p,m⁰), entropy (S_m⁰), and enthalpy (H_m⁰). The ¹H and ¹³C NMR chemical shifts are calculated using the GIAO method and compared with the experimental data. Molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analyses are also performed to study the electronic characteristics of the title compound.