Chemistry

Phase equilibria and salting out of butyric acid in the ternary system potassium nitrate + water + 2-(2-butoxyethoxy)ethanol

Visual polythermal method in the bynary system of water-2-(2-butoxyethoxy) ethanol in the range of –25÷0° C the ice melting line is determined and the phase equilibria in the ternary system potassium nitrate–water–2-(2-butoxyethoxy) ethanol are studied in the range of 10.0–90.0° C. The ice melting line in the water–2-(2-butoxyethoxy) ethanol binary system is a flat, smooth line. This form of the melting line shows a hidden separation in liquid mixtures.

Extractive crystallization of salts in the ternary systems sodium (potassium, cesium) nitrate – water – triethylamine

A comparative analysis of the results of our polythermal study of the ternary systems sodium (potassium, cesium) nitrate – water – triethylamine has been carried out to estimate the efficiency of the use of triethylamine in the extractive crystallization of alkali metal nitrates from water–salt solutions containing 43.0, 44.0, 45.0, 46.0, and 47.0 wt. % sodium nitrate in the range of 10.0–25.0°C, 20.0, 21.0, and 22.0 wt.% potassium nitrate and 18.0, 19.0, 20.0 and 21.0 wt. % cesium nitrate in the range of 20.0–25.0°C.

Glauconite as a sorbent of 4-nitrophenol

The sorption properties of glauconite from Beloozersk deposits (Saratov region) for 4-nitrophenol (4-NF) have been investigated. The effect of glauconite on pH and 4-nitrophenol structure in solution is estimated. It is shown that glauconite increases pH of aqueous environment to 8 and shifts the equilibrium towards the formation of aci-form 4-NF. The conditions of sorption 4-NF by glauconite are established: the sorption time 20 min, the mass of the sorbent (0.50–1.0) g.

Effect of sulfur solvent on the properties of lead sulfide quantum dots

Colloidal quantum dots (QDs) of lead sulfide have been synthesized and investigated using octadecene and white spirit as a solvent for sulfur, varying the concentration of precursors and the temperature of the process. A method has been proposed for the synthesis of these QDs using anhydrous white spirit as a solvent at a temperature of 200° C, which made it possible to obtain polygonal nanoparticles with an average diameter of 2 to 3.2 nm with a minimum spread in size (± 10%).

The influence of nature of active components and modifiers on electroanalytic properties of planar cefalexine-selective sensors

The 1st generation cefalexine-cephalosporine antibiotic is used in the treatment of various infectious diseases. Spectrophotometry, kinetic spectrophotometry, spectrofluorimetry are proposed to determination of cefalexine in medicine and biological environment. Planar screenprinted sensors allow analyzing the micro-volumes of samples, which is important for the analysis of biological objects without preliminary samplepreparation. Depending on the active material and modifiers, you can create planar sensors for the determination of different organic compounds.

One-pot synthesis and structure of isomeric aryl-substituted triazolohexahydroquinazolines

Aryl-substituted triazolohexahydroquinazolines have been synthesized by means of three-component condensation of pnitro(pbromo) benzaldehydes, cyclohexanone, 1,2,4-triazol-3-amine. A scheme of the reaction mechanism is proposed, which makes it possible to explain the features of the behavior of p-nitro(bromo) benzaldehydes in condensation reactions in comparison with their ortho-substituted analogs.

Phase diagram of the β-alanine – water binary system

The phase diagram of the β-alanine–water binary system was studied using the visual polythermal method and the method of time–temperature curves in а temperature range of -20–90°С. There is a eutectic equilibrium at -18.3°С in the system; the solid phases of this equilibrium are ice and individual β-alanine. For the first time, the composition of the liquid phase of the eutectic state was determined.

Investigation of nikel(II) complexing with 2,6-dimerkapto-4-methilphenol and aminophenols

Complexing of nickel(II) with 2,6-dimercapto-4-methylphenol (DMMP) and hydrophobic amines was studied using physicochemical methods. Hydroxyl-containing amines-aminophenols (AP) were used as a hydrophobic amine. On the part of aminophenols, 2 (N, N-dimethylaminomethyl) -4-methylphenol (AP1 ), 2 (N, N-dimethylaminomethyl)-4-chlorophenol (AP2 ), and 2 (N, N-dimethylaminomethyl) -4-bromophenol (AP3 ) were used. Mixed-ligand complexes were formed in a weakly acidic medium (pHopt 4.6–6.4).

Adsorption of organic reagents by natural bentonites modified with aluminum and iron (III) polyhydroxocations

The effective nanostructured sorbents based on natural bentonite modified with aluminum and iron (III) polyhydroxocations were obtained. The elemental composition of the obtained sorbents was studied. The specific surface area was determined for the studied samples. It was shown that modified sorbents based on natural bentonite were nanostructured objects. IR spectroscopy showed that modification of natural bentonite led to the changes in its structural properties.

Branched polymers of N-isopropylacrylamide: A 2005–2020 review of english literature

The search and the analysis of English scientific literature from 2005 to 2020 devoted to the methods of obtaining branched polymers and copolymers of N-isopropylacrylamide were made in order to obtain novel materials with valuable properties. It was found that modern methods of controlled radical polymerization were mainly used for this purpose, namely, atom transfer radical polymerization (ATRP), polymerization with reversible addition-fragmentation chain transfer (RAFT) and group transfer polymerization (GTP). In most cases the original compounds were the chain transfer agents in RAFT.

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