Doklady Chemistry最新文献

Reducing carbon dioxide emissions during production is one of the main trends in modern oil and gas chemistry. One of the most realistic possibilities for achieving this is to involve carbon dioxide generated in technological processes as a feedstock for producing gas chemical products. The maximum effect can be achieved in the production of large-scale chemicals, such as syngas, hydrogen, and methanol. We consider such possibilities and present a new combined autothermal process for the joint production of hydrogen and methanol based on non-catalytic matrix conversion of natural gas into syngas, which allows one to almost avoid CO₂ emissions.

A first-generation triazole-containing dendron with hydroxypropyltriazole groups and a tetraethylene glycol linker was synthesized for the first time by stepwise modification of gallic acid by the azide–alkyne cycloaddition reaction. The structures of all intermediate compounds have been proven by advanced physical methods. It has been found that, due to the high mobility of the bromine atom in the benzylic position, the use of bromomethylene gallic acid derivatives in the synthesis of triazole-containing dendrons gives by-products resulting from alkylation of the bases used in the reaction (triethylamine and diisopropylethylamine).

An efficient synthesis of optically pure macrocyclic mono- and binuclear polylactones has been proposed. The synthesis is based on the condensation of natural triol, castor oil, with sebacoyl dichloride in 1 : 1 or 1 : 2 ratios in boiling carbon tetrachloride in the presence of triethylamine and N,N-dimethylaminopyridine as a catalyst.

Previously unknown phenyl-substituted iodo-δ-lactone derived from 11‑phenylundeca-5Z,9Z-dienoic acid was synthesized in 94% yield using the Ti-catalyzed intermolecular cross-cyclomagnesiation of aromatic 1,2-diene with O‑containing allene at the key stage. The in vitro cytotoxic activity of synthesized alkyl- and phenyl-substituted iodo-δ-lactones of 5Z,9Z-dienoic acids against the Jurkat, K562, U937, HL60, and Hek293 cell lines was studied, and their effect on the cell cycle and the ability to induce apoptosis were investigated using flow cytometry.

Methods have been proposed for the preparation of new polyfunctional heterocyclic compounds based on the addition of dichlorocarbene and ethanol to the terminal double bond of 2,2-disubstituted 4-methylene-1,3-dioxolanes, as well as on hydrogenation and ozonolysis of this bond.

The highly alkaline multicomponent systems TiO₂–H₂SO₄–Na₂SiO₃–NaOH–H₂O and TiO₂–H₂SO₄–(NH₄)₂SO₄–Na₂SiO₃–NaOH–H₂O have been studied under conditions of hydrothermal synthesis, which gives new products with specified technical properties. It has been shown that, by a targeted selection of structure-forming components, in particular, titanium compounds, together with optimal parameters of hydrothermal treatment of the formed precursor, one can obtain compounds with given chemical composition and particle size and morphology. It has been found that the rate of structural transformations in the synthesis depends on the phase composition of titanosilicate precursors. Their hydrothermal treatment involves the alkaline and thermal hydrolysis followed by dehydration of the hydrolyzed phases of titanium(IV) and silicon. This is accompanied by the localization of free bonds ensuring the formation of Ti–O–Si–O bridges and their subsequent transformation into new structured species.

Radical copolymerization of coumarin with N-vinylamides (N‑vinylpyrrolidone, N-methyl-N-vinylacetamide, N-vinylformamide) has been used to prepare copolymers of various composition with variable molecular weights. Subsequent reactions in their polymer chains affords water-soluble copolymers of salts of hydroxycinnamic acid and its hydrazides. The synthesized copolymers of hydroxycinnamic acid salts and hydrazides with N-vinylamides have low cytotoxicity and demonstrate the pronounced antiviral activity against human respiratory syncytial virus (strain A2).

The paper presents a new low-temperature method for the synthesis of fine powders of double phosphates LiCoPO₄ and LiNiPO₄ using a low-waste technology. It has been shown that the morphology and particle size distribution of the synthesized materials are determined by the type of precursor used. The resulting compounds are characterized by chemical analysis, X-ray powder diffraction analysis, scanning electron microscopy, cyclic voltammetry, and cyclic chronopotentiometry. The new approach to the synthesis of submicron powders of lithium and transition metal (nickel or cobalt) double phosphates is more efficient than the existing conventional methods.

The phenomenon of selective sorption of a stable nitroxyl radical TEMPO on rubber particles in the powder of dried and dispersed root of kok-saghyz has been discovered. This feature of the rubber-bearing root material has contributed to the development of a new, highly sensitive method of quantitative analysis of rubber by measuring the integrated intensity of the EPR TEMPO signal. The main advantages of the proposed method are the speed and the ability to determine the content of rubber directly in the roots of the plant in microquantities (5–30 mg).

The possibility of using widely available stearin to produce fatty acid-derived ionic liquids (ILs) has been shown for the first time. New amphiphilic ILs based on imidazolium, pyridinium, and quaternary ammonium cations containing long-chain alkyl substituents have been prepared. The synthesized compounds have been shown to have biological activity comparable to known antimicrobial compounds. ILs with one alkyl substituent have higher cytotoxicity and antimicrobial activity compared to disubstituted derivatives.