THEORETICAL STUDY OF CHLORINATION REACTION OF NITROBENZENE FROM DFT CALCULATIONS

The geometric parameters of stationary points on the potential surface energy of the chlorination reaction of nitrobenzene in the presence of Aluminium chloride as catalyst were investigated theoretically by hybrid DFT (Density Functional Theory) calculations in order to determine his general reaction mechanism in gas phase and in solution. The results obtained by DFT have been compared with CCSD(T) method which is the most powerful post-Hartree Fock method in terms of inclusion of dynamic correlation. Although the electrophilic substitution reaction is widely taught in most courses in organic chemistry, the mechanism has been very few studied theoretically. The results obtained in gas phase are consistent with the traditional description of these reactions: the orientation of this substitution in meta position depends on the stability of a reaction intermediate (Wheland said). Without taking in consideration the reactants and products, six stationary points are found on the potential surface energy of this reaction. The reaction has also been studied in the presence of solvent and we’ve noted that the influence of solvent decreases the electrostatic attraction on the Wheland complex, but the general reaction mechanism remains unchanged in solution

Crystal structure of tris[4-(dimethylamino)pyridinium] tris(oxalato-κ2O,O′)chromate(III) tetrahydrate

In the title hybrid salt, (C7H11N2)3[Cr(C2O4)3]·4H2O, the central CrIII ion of the complex anion (point group symmetry 2) is coordinated by six O atoms from three chelating oxalate(2−) ligands in a slightly distorted octahedral coordination sphere. The Cr—O bond lengths vary from 1.9577 (11) to 1.9804 (11) Å, while the chelate O—Cr—O angles range from 82.11 (6) to 93.41 (5)°. The 4-(dimethylamino)pyridinium cations (one situated in a general position and one on a twofold rotation axis) are protonated at the pyridine N atoms. In the crystal, N—H...O and O—H...O hydrogen bonds link the cations and anions into a three-dimensional network. π–π interactions between the pyridine rings of adjacent cations provide additional stabilization of the crystal packing, with the closest centroid-to-centroid distances being 3.541 (1) and 3.575 (1) Å

Pyridinium trans-diaquabis[oxalato(2−)-κ2O1,O2]chromate(III) urea monosolvate

The asymmetric unit of the title solvated molecular salt, (C5H6N)[Cr(C2O4)2(H2O)2]·CO(NH2)2, contains half a formula unit. Each component is completed by crystallographic twofold symmetry: in the cation, one C and the N atom lie on the rotation axis; in the anion, the CrIII ion lies on the axis; in the solvent molecule, the C and the O atom lie on the axis. The aqua ligands are in a trans disposition in the resulting CrO6 octahedron. In the crystal, the components are linked by O—H...O, N—H...O and N—H...(O,O) hydrogen bonds, generating a three-dimensional network

Анализ эффективности проведения гидроразрыва пласта на Ямбургском нефтегазоконденсатном месторождении (ЯНАО)

Цель данной работы – определить, насколько целесообразно проведение ГРП с технологической и экономической точки зрения, выявить главные аспекты, проанализировать эффективность данного метода на N–ом нефтегазоконденсатном месторождении. Основными задачами является: освещение сущности ГРП как метода интенсификации притока на N–ом нефтегазоконденсатном месторождении; анализ основных характеристик процесса ГРП, с целью определения эффективности данного метода; так же проведение экономического расчета ГРП для определения рентабельности данного метода. По окончанию выполнения поставленных задач можно будет судить о том, на сколько эффективно проведение ГРП на N–ом месторождении.The purpose of this paper is to determine the feasibility of the Hydraulic fracturing treatment from a technological and economic point of view, to identify the main aspects, to analyze the method at the N oil and gas condensate hall. The main tasks are: to illuminate the nature of the hydraulic fracturing as a method of intensifying the inflow at the N oil and gas condensate hall; Analysis of the main characteristics of the fracturing process, in order to determine the effectiveness of this method; In the same way, the economic calculation of the hydraulic fracturing is carried out to determine the variability of this method. After the completion of the tasks, it will be possible to judge how efficient the hydraulic fracturing at the N field is

Two tris(oxalato)ferrate(III) hybrid salts with pyridinium derivative isomers as counter cations: synthesis, crystal structures, thermal analyses, and magnetic properties

International audienceTwo organic–inorganic hybrid salts, tris(2-amino-4,6-dimethylpyridinium) tris(oxalato)ferrate(III), (C7H11N2)3[Fe(C2O4)3] (1), and tris(4-dimethylaminopyridinium) tris(oxalato)ferrate(III) tetrahydrate, (C7H11N2)3[Fe(C2O4)3]·4H2O (2), have been synthesized and characterized by elemental and thermal analyses, IR spectroscopy, single-crystal X-ray diffraction, and SQUID magnetometry. Compounds 1 and 2 crystallize in triclinic P-1 and monoclinic C2/c space groups, respectively. Each compound contains the anionic complex [Fe(C2O4)3]3- in which the central metal is six-coordinate in a slightly distorted octahedron defined by three chelating oxalate(2-) ligands. The two substituted pyridinium cations are isomers. However, due to the great steric hindrance provided by the bulky cation, 2-amino-4,6-dimethylpyridinium, only the 4-dimethylaminopyridinium cation, the smallest of this series, led to formation of 2 with enough vacant spaces to be occupied by four solvent water molecules. In the crystals, cations and anions are connected via hydrogen-bonds of the types N–H⋯O in 1 and N–H⋯O and O–H⋯O in 2, with π–π stacking interactions between the pyridine rings stabilizing the 3-D framework. The thermal studies confirmed the anhydrous character of salt 1 and the presence of water molecules in salt 2. The magnetic susceptibility measurements in the 2–300 K temperature range revealed weak antiferromagnetic coupling in the two salts