Chemistry

Interaction of Maleic Anhydride with 1,2-phenylenediamine under Different Conditions

The reaction of maleic anhydride with 1,2-phenylenediamine when heated in an aprotic solvent, regardless of temperature, proceeds with the initial formation of the primary addition product, namely, 4-[(2-aminophenyl)amino)-4-oxobut-2-enoic acid, which further undergoes heterocyclization within two ways, due to the presence of several electrophilic centers in the molecule, depending on the reaction conditions.

Synthesis and Ways of Formation of Hydroxyphenyl Substituted Triazolohexahydroquinazolines

With three-component condensation of 1,2,4-triazol-3-amine, hydroxy-substituted aromatic aldehyde (2-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 2-naphthalene-carbaldehyde), cyclohexanone, the aldehyde component has a defining impact on the shaping of triazologic hydroquinazolines with different types of rings articulation and the position of the double bond in them (C4a–C5 and C4a–C8a). When salicylic aldehyde is used, the positional isomers of the triazologic hexahydroquinazolines of angular and linear structure are formed in an equimolar ratio.

Exploration of Possibilities for Organic Selenides and Dihydroselenochromilium Salt Interaction with Diphenylpicrylhydrazyl

Higher fungi – basidiomycetes play significant role as food and biological subjects for establishing the regularities of the living systems’ operation, development and response to the different-nature effectors impact. Insufficient activity of the living organisms’ antioxidant system interfering the ability of overcoming the negative consequences of oxidative stress (excessive level of free radicals in cells) is believed to be a reason for the organisms aging and death.

Ionic Aggregation of Macromolecules as the Cause of the Kinetic (Non)Stability of Physicochemical Properties of Chitosan Solutions

Hydrodynamic, optical, colloid-flocculating, film-forming and structural morphological properties of diluted chitosan solutions (50–640 kDa) in acetate buffer (0.33 М СН3СООН + 0.2 М СН3СOONa), both initial ones and stored for ~1,850 days, were studied. It has been established that the decrease in the intrinsic viscosity of solutions over time is manifested for the reprecipitated and high-molecular-weight samples of chitosan to a greater degree. The viscosity drop effect is not affected by the use of untreated or sterile degassed distilled water to dissolve the polymer.

Rare Earth Metal Iminodisuccinates

Iminodisuccinates of several rare earth metals (REM) have been synthesized as a result of reaction between freshly prepared ammonia iminodisuccinate and REM chloride soltuions at pH 3. According to element analysis data, the chemical composition of synthesized salts is MeHC8H7O8N · nH2O, where Ме = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, n = 1–5. Synthesized compounds were further analyzed via X-ray diffraction and thermogravimetric analysis. According to X-ray data, REM iminodissucinates form well-defined crystals in two distinct isostructural groups.

Application of the Sodium Arsenite Hydrolysed for Obtaining Pure Arsenic Products

The article presents information about the possibility of using sodium arsenite hydrolyzed as a new type of arsenic-containing raw material for obtaining marketable products of various qualities. The methods of purification of arsenic (III) oxide as the main product of sodium arsenite hydrolyzed processing to various degrees of purity (3-6N) are given, which allows using it as a raw material for the synthesis of a wide range of arsenic compounds: arsenic acid, elemental arsenic, arsenic trichloride.

Express Method for Cefazolin Determination in Small Samples Sensors Planar Potentiometric

The unmodified and modified by polyaniline and nanoparticles planar potentiometric sensors on the basis of tetradecylammonium associates with a complex silver (I) – cefazolin are created. Optimum ratios of components in carbon-containing ink are established: 30–32% carbon powder, 16–18% polyvinylchloride, 48–50% dibutylphthalate and 1–3% of electrode active compound (EAC). Planar sensors of two types are examined: electrode active compounds, electrode active compound and modifiers were added into in carbon-сontaining ink.

The Influence of the Composition of Subphase and External Conditions on the Formation and Properties of Langmuir Monolayer

The specifity of the formation of arachinic acid monolayers (used as models of cell membranes) by the Langmuir method on a subphase containing L-ascorbic and D-isoascorbic acids with a concentration of 10-2, 10-3 M at a temperature of 25, 37 and 41°C was studied. The influence of the isoforms of ascorbic acid, the composition and temperature of the subphase on the mechanical properties of monolayers (specific area, compressibility, collapse pressure) was experimentally found.

Receiving Oil Sorbents from Renewable Agricultural Raw Materials

A method is proposed for obtaining a promising cellulosecontaining oil sorbent based on the buckwheat shell and millet shell, suggesting its modification by compounds structuring the polymer followed by heat treatment. These modification methods contribute to the creation of carbon structures with controlled porosity, as well as an increase in the yield of carbonized structures after heat treatment. Sorption properties of materials based on modified plant raw materials are investigated.

Prospects for the Development of Biomimetic Hybrid Materials Based on the Layer-by-Layer Assembly Technique

Natural composite structures, such as horn bones and nacre (or socalled mother-of-pearl), are characterized by a structural organization ordered at the nanoscale. This material architecture has attracted a wide interest order to develop new hybrid composite materials with tunable mechanical properties. The сurrent review aimed to establish the prospects for the development of artificial methods for synthesis of mechanically strong biomimetic materials.

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