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2025, №1

pp. 3-14

Articles

Key words: supercritical fluid carbon dioxide, biodeterioration, micromycetes, mildew, fungicidal effect, disinfection, paper

For the first time in Russia, experience was used to evaluate the fungicidal effect of supercritical fluid carbon dioxide on 12 types of micromycetes that destroy paper. For the purpose of further use for disinfection treatment of library and museum collections, the effectiveness of various modes was assessed on paper samples with foci of biodamage caused by the micromycete Aspergillus niger: pure supercritical carbon dioxide and with the addition of ethanol as a co-solvent at a concentration of 2% and 4 %. Pure supercritical carbon dioxide results in minimal reduction of microorganisms on the surface of samples. Treatment with supercritical carbon dioxide in the presence of alcohol as a co-solvent has a pronounced fungicidal effect, which was demonstrated on all test cultures. Processing in supercritical carbon dioxide with the addition of 4% ethanol with stirring allows for a high degree of sterilization and is a promising method for processing library collections.

doi:10.34984/SCFTP.2025.20.1.001

2025, №1

pp. 15-26

Articles

Key words: supercritical fluid, supercritical carbon dioxide, copper salts, copper carbonate, copper acetate, copper thiocyanate, copper benzoate, polymer composite materials

The solubility of a series of copper salts (carbonate, acetate, benzoate and thiocyanate) in supercritical carbon dioxide at 308—328 K and 10—30 MPa was determined. The results were described using the Peng—Robinson equation of state and the Mukhopadhyay and Rao mixing rule. The results are necessary for developing technological approaches to the impregnation of polymeric materials and creating composite materials based on them.

doi:10.34984/SCFTP.2025.20.1.002

2025, №1

pp. 27-41

Articles

Key words: supercritical fluids, density, fibre-optic densitometer, CO2 hydrogenation, phenol conversion

The dependences of the reaction mixture density on temperature are analyzed for the following processes: 1) catalytic hydrogenation of CO2; 2) conversion of phenol and cyclohexanol in sub- and supercritical water. The density measurements were performed using «Lazerokhim» fiber-optic densitometer. The state of the waveguide end face surface after measurements at elevated temperature was analyzed using scanning electron microscopy (SEM). It was found that for non-aqueous reaction mixtures, the laser-optical method of density monitoring is applicable in a wide range of temperatures and pressures. In the case of water and water-organic mixtures, correct determination of the densities is possible only at temperatures of 25—190°C, since an increase in temperature above 200°C leads to irreversible etching of the silicate optical waveguide end face surface by water-containing fluid.

doi:10.34984/SCFTP.2025.20.1.003

2025, №1

pp. 42-54

Articles

Key words: supercritical lower alcohols, methanol, bornyl acetate, borneol, fir needle oil, transesterification reaction

A non-catalytic transesterification (alcoholysis) reaction of bornyl acetate in commercial fir needle oil has been carried out for the first time using supercritical lower alcohols - methanol, ethanol and isopropanol. Only the use of methanol is shown to provide high conversion and selectivity of the reaction. Thus, at 350 °C for 1 hour of reaction in autoclave-type reactor 93 % selectivity on borneol with 90 % conversion of bornyl acetate was achieved. A further increase in reaction time leads to a decrease in borneol selectivity, accompanied by an unexpected increase in camphor concentration.

doi:10.34984/SCFTP.2025.20.1.004

2025, №1

pp. 55-65

Articles

Synthesis of Transparent Amino-Modified SiO2 Aerogels and their Derivatives

N.A. Sipyagina, I.O. Gozhikova, N.E. Vlasenko, G.P. Kopitsa, S.A. Lermontov.

Quote

Key words: aerogels, silica, dimethyl sulfoxide, transparency, modification

Dimethyl sulfoxide (DMSO) is proposed as a solvent at the gelation stage during the synthesis of transparent aerogels based on tetramethyl orthosilicate and 3-aminopropyltrimethoxysilane (APTMS). The transparency of the aerogels varied depending on the content of the aminopropyl fragment. The textural characteristics of the aerogels were studied. It was shown that the use of DMSO instead of isopropanol, a standard solvent for the synthesis of gels, allows one to significantly increase the specific surface area of the aerogels. Using DMSO as a solvent, transparent aerogels based on APTMS and modified with fragments of perfluorononanoic acid and L-phenylalanine were obtained. The possibility of obtaining transparent aerogels containing amino complexes of transition metals, namely copper and palladium, was demonstrated.

doi:10.34984/SCFTP.2025.20.1.005

2025, №1

pp. 66-80

Articles

Key words: molecular descri ptor, supercritical carbon dioxide, solubility, method QSPR, software and analytical complex, database

Mathematical models of the solubility of various groups of organic substances in supercritical carbon dioxide are proposed. The developed models are based on the quantitative structure-property ratio method. The key feature of the method is to obtain the relationship between the predicted property and the structure of the substance molecule (molecular descri ptors). As part of the work, molecular descri ptors affecting solubility were selected and dependences of the solubility of organic substances in supercritical carbon dioxide were obtained using the multiple linear regression method. The models were developed using a developed software and analytical complex and an original database containing information on the solubility of substances in supercritical carbon dioxide and information on the molecular descri ptors of soluble substances. The predictive ability of the developed models was evaluated using training and test samples of experimental data on the solubility of substances in supercritical carbon dioxide at various pressure and temperature parameters. Based on the results obtained, it was concluded that the developed models are promising for predicting the solubility of substances in supercritical carbon dioxide.

doi:10.34984/SCFTP.2025.20.1.006

2025, №1

pp. 81-94

Articles

Key words: polymeric membranes, gas separation, 1,2-disubstituted polyacetylenes, CO2 capture, chemical modification of polymers, ionic liquids

This study focuses on the chemical modification of a polymer promising for gas separation membranes to enhance its CO2 selectivity. The possibility of introducing butylimidazolium bromide (BIm+Br-) into the structure of poly(1-trimethylsilyl-1-propyne) (PTMSP) via a two-step process was demonstrated: bromination of the initial polymer with N-bromosuccinimide followed by reaction with a tertiary amine—N-butylimidazole. Supercritical CO2 and CHF3 were used as reaction media, offering advantages over organic solvents, such as non-toxicity, non-flammability, and environmental safety. Depending on the process conditions, the proposed method allows for tuning the BIm+Br- content in the polymer structure. The obtained modified polymers exhibit good film-forming properties, thermal stability, and enhanced resistance to aliphatic, alicyclic, halogenated, and aromatic hydrocarbons. It was found that increasing the BIm+Br- content in the polymer improves the selectivity of CO2/N2 and CO2/CH4 separation while maintaining high gas permeability. These results open new possibilities for designing efficient membrane materials for industrial gas separation applications.

doi:10.34984/SCFTP.2025.20.1.007