Objectives. When developing separation flowsheets for liquid mixtures, preference is often given to a specific process or flowsheet. Although alternative separation variants are sometimes considered, these tend to be based on a single-phase process, usually distillation. And while review papers on the specifics of implementing a particular separation technique exist, these mainly focus on the specific process of extractive distillation, combination of distillation and splitting processes, and extraction. Moreover, studies comparing the separation flowsheets of mixtures of different physicochemical nature based on different processes and special methods are fragmentary. This study presents a comparative analysis of the processes and methods of liquid mixtures separation based on a critical review of the literature and the authors’ own research results.

Methods. The study is based on the critical analysis of literature and mathematical modeling of phase equilibria using local composition equations via freely distributed software packages.

Results. Specific liquid mixture separation methods, including combining various processes in one flowsheet (including hybrid technologies), are compared in terms of their advantages and disadvantages.

Conclusions. Promising areas of further research in the field of synthesis of organic mixtures separation flowsheets through the use of various separation processes and methods are identified. The effectiveness of the various processes (extraction, splitting, special distillation techniques) is estimated at different stages of different number of components mixtures separation. A comparative analysis of extractive and heteroazeotropic distillation processes when separating mixtures of different initial composition highlights the areas of energy advantage of each process. The effectiveness of the flowsheets is estimated by combining extraction with other processes, depending on the stage of extractant regeneration.

Objectives. Oral administration of ibuprofen often requires much higher doses than the necessary therapeutic dose due to the low solubility and first-pass metabolism of this anti-inflammatory drug. In order to improve its solubility and bioavailability, orally administered ibuprofen can be encapsulated into chitosan nanoparticles. The release of ibuprofen from chitosan nanoparticles can be pH-controlled to increase drug delivery efficiency when passing through the gastrointestinal tract. While ionic gelation provides versatile nanochitosan synthesis, the impact of the chitosan-to-tripolyphosphate (CS/TPP) ratio on encapsulation efficiency (EE) and loading capacity (LC) of the ibuprofen-loaded chitosan nanoparticles (IBU-CSNPs), as well as their release behavior under various pH conditions, remains unexplored. The study aims to determine the appropriate CS/TPP ratio for the highest EE and LC, as well as to evaluate the morphology, release behavior, and degradability of the IBU-CSNPs under optimal conditions.

Methods. The effect of CS/TPP ratio on the EE and LC of nanoparticle-loaded ibuprofen is studied by comparing the total and free concentrations of the drug and the weights of the CSNPs and IBU-CSNPs. To elucidate the characteristic properties of the IBU-CSNPs prepared at the optimal CS/TPP ratio, in-depth characterization was performed, including their morphology, chemical structure, crystallinity profile, in vitro degradation, and release behavior. The release profile of the IBU-CSNPs is studied under simulated gastric fluid (SGF), intestinal fluid (SIF), and sequential conditions of SGF and SIF.

Results. EE and LC were found to be significantly enhanced by an appropriate 1 : 1 mg/mg ratio, reaching 77.70 ± 0.65% and 46.62 ± 0.39%, respectively. The fabricated IBU-CSNPs exhibit a spherical shape with a uniform size distribution of approximately 50–60 nm and accelerated degradation compared to the unadulterated chitosan nanoparticles under simulated gastrointestinal conditions. The synthesized IBU-CSNPs demonstrate remarkable acid resistance by a minimal drug release of 9.44% in SGF after 3 h. However, a sustained release pattern in SIF achieves an equilibrium cumulative release of 94.51% over 5 days. The elaboration of drug release kinetics using the Kopcha and Korsmeyer–Peppas models suggests erosion-controlled release in SGF and diffusion-controlled release with swellable ability in SIF.

Conclusions. The results represent valuable insights into the formulation of pH-responsive IBU-CSNPs for the controlled delivery of ibuprofen via oral administration.

Objectives. Gene therapy techniques based on the introduction of therapeutic nucleic acids into body cells are currently being developed for the treatment of diseases with a genetic etiology. Among modern drug delivery systems, nonviral agents based on the use of a variety of lipids to produce liposomes and micelles occupy a special place. This work sets out to synthesize and study the properties of dimeric cationic amphiphiles of irregular structure with symmetric and asymmetric hydrophobic blocks in order to determine the influence of structure on physicochemical properties and evaluate the prospects of their application as transfection agents.

Methods. The formation of hydrophobic and hydrophilic blocks involves reactions of L-cystine derivatives and L-glutamic acid and diethanolamine diesters using the condensing agents: dicyclohexylcarbodiimide (DCC) + 4-(dimethylamino)pyridine (DMAP) or hexafluorophosphate benzotriazole tetramethyl uranium (HBTU) + diisopropylethylamine (DIPEA). In order to isolate the reaction products from the reaction mixture, column chromatography and/or preparative thin-layer chromatography on silica gel were used. The structure of the obtained compounds was confirmed by 1H nuclear magnetic resonance spectroscopy and mass spectrometry. Synthesized lipopeptides in aqueous medium formed liposomal dispersions whose particle size was determined by photon correlation spectroscopy.

Results. Schemes for the preparation of novel dimeric cationic amphiphiles based on L-cystine derivatives were devised. The hydrophobic blocks of the obtained compounds include diesters of diethanolamine and L-glutamic acid (C10, C14, and C16). Targeted lipopeptides were used to obtain liposomal dispersed systems mixed with natural lipids. The hydrodynamic size of the particles formed in all dispersions was determined to be within the range of 50 to 200 nm.

Conclusions. The physicochemical properties of aqueous dispersions based on the synthesized compounds were investigated. Dimeric amphiphiles mixed with phosphatidylcholine and cholesterol form liposomal particles. The impact of amphiphile structure on aggregate size was demonstrated. The number of L-ornithine residues (0, 1, 2) in the target products was found to be the most significant parameter affecting the particle size.

Objectives. This study aims to investigate the kinetics and thermodynamics of furfural extraction from sweet potato peels using dichloromethane (CH₂Cl₂) as a solvent and sulfuric acid as a catalyst. To that end, we set out to determine the kinetic parameters for furfural production using first- and second-order models, optimize the extraction temperature, and evaluate the thermodynamic properties of the reaction.

Methods. Potato peels, selected for their high hemicellulose content, cost-effectiveness, and sustainability, were processed with dichloromethane, selected for its safety, low energy requirements, and compatibility with green extraction processes. Experimental conditions involved varying temperatures (60, 70, and 80°C) and peel powder particle sizes (<5 mm), with the reaction being monitored to fit kinetic models and calculate thermodynamic properties.

Results. Experimental findings revealed that the first-order kinetic model provided the best fit, with an activation energy (Eₐ) of 85.99 kJ/mol. Thermodynamic analysis showed an enthalpy change (ΔH) of 83.14 kJ/mol, entropy change (ΔS) of −86.08 J/(mol·K), and Gibbs free energy (ΔG) values ranging from 111.80 to 112.66 kJ/mol across the studied temperatures. Optimal extraction conditions were achieved at 80°C, yielding the highest furfural concentration through acid-catalyzed hydrolysis. The energy-intensive yet controlled nature of the reaction highlights the need for further optimization.

Conclusions. This study demonstrates the effectiveness of dichloromethane as a solvent for furfural extraction from sweet potato peels under optimized conditions. The kinetic and thermodynamic findings elucidate the reaction mechanism and its industrial applicability. Future studies should focus on simulating furfural separation from ternary solvent systems using Aspen Plus to enhance sustainability and scalability.

Objectives. The work set out to obtain the corresponding cyclohexenyl derivatives of 1,4-dioxaspiro[4.5]decane, 1,5-dioxaspiro[5.5]undecane, and 1,4-dithiaspiro[4.5]decane by condensation of 2-(cyclohexen-1-yl)cyclohexanone (Wallach ketone) with 1,2-, 1,3-diols, and 1,2-ethanedithiol; to determine reaction duration and process temperature at which the maximum possible yield of the target cyclic derivatives of 2-(cyclohexen-1-yl)cyclohexanone is achieved; to evaluate the anticorrosive properties of the obtained acetals in an acidic medium; to carry out dichlorocarbenation using 1,4-dioxaspiro[4.5]decane as an example, and to establish the structure of the obtained isomers.

Methods. Target compounds including cyclic acetals were obtained by a classical organic synthesis method involving condensation of 2-(cyclohexen-1-yl)cyclohexanone (Wallach ketone) with 1,2-, 1,3-diols, and 1,2-ethanedithiol. The following analysis methods were used to determine the qualitative and quantitative composition of the reaction masses: gas–liquid chromatography (Crystallux-4000M chromatograph with a flame ionization detector, a 25 m × 0.33 mm capillary column containing 100% polydimethylsiloxane as a stationary phase 0.5 μm), nuclear magnetic resonance spectroscopy (BrukerAM-500 device with operating frequencies of 500 and 125 MHz), and elemental microanalysis (rapid gravimetry method). Chlorine and sulfur were determined by the Schöniger method.

Results. Under conditions of thermal heating of Wallach ketone with 1,2-, 1,3-diols, and 1,2-ethanedithiol, 1,4-dioxaspiro[4.5]decane, 1,5-dioxaspiro[5.5]undecane, and 1,4-dithiaspiro[4.5]decane were obtained with a yield of 95%. 5,5-Dimethyldioxane derivative was found to have a moderate inhibitory effect on acid corrosion of carbon steel St20 at a temperature of 60°С. Dichlorocarbenation of 1,4-dioxaspiro[4.5]decane was shown to occur with the formation of a mixture of two diastereomers (ratio is 1 : 2) as evidenced by doubled signals of carbon atoms in the carbon spectrum.

Conclusions. 2-(Cyclohexen-1-yl)cyclohexanone 1 condenses with 1,2-, 1,3-diols, and ethanedithiol to form the corresponding spirocyclic derivatives in high yields. It is shown that 1,4-dioxaspiro[4.5]decane undergoes dichlorocarbenation under Mąkosza reaction conditions to form polycyclic gem-dichlorocyclopropane as a mixture of two diastereomers. 7-(Сyclohex-1-en-1-yl)-3,3-dimethyl-1,5- dioxaspiro[5.5]undecane is confirmed to inhibit steel corrosion in acidic media.

Objectives. To investigate the influence of hydrodynamic cavitation on the group hydrocarbon composition of straight-run fuel oil and the structural characteristics of its asphaltenes.

Methods. The cavitation treatment of fuel oil was carried out in hydrodynamic mode using a Donor-2 device. The pressure drop in the working part was 50 MPa, while the number of treatment cycles varied from 1 to 10. In some cases, to intensify the process, the fuel oil was compounded with low-boiling hydrocarbons (propane-butane fraction, decalin). The determination of the group hydrocarbon composition of the sample was based on the different solubility of hydrocarbons in polar and nonpolar solvents; asphaltenes were studied by diffractometry and Raman spectroscopy.

Results. It is shown that the group hydrocarbon composition of the sample changes as a result of the cavitation effect: the content of resins and asphaltenes decreases, the amount of the oil fraction increases, and its group hydrocarbon composition is altered. It was found that cavitation exposure also changes the structural characteristics of asphaltenes: they decrease the La and Lc crystallite parameters that characterize their dimensions in plane and height, as well as increase the distance between alkyl substituents and the degree of plasticity of asphaltenes. The processing of Raman spectra by various methods demonstrated consistent results: in all cases, an increase in the intensity of exposure led to an increase in the structural disorder of asphaltenes. In the case of preliminary compounding of the sample with low-boiling hydrocarbons, the effect of cavitation was enhanced.

Conclusions. The results obtained may indicate the localization of cavitation bubbles at the boundaries of complex structural units of the dispersed petroleum system formed by asphalt-resinous substances and a dispersion medium. For this reason, it is resins and asphaltenes that are most exposed to the thermal effects that occur when cavitation bubbles collapse. The destruction of resins and asphaltenes leads to a decrease in the size of complex structural units and consequent decrease in the viscosity of the petroleum dispersed system, while the oil fraction is enriched with saturated hydrocarbons. 

Objectives. Ethylbenzene is an important intermediate for styrene production. Most of the ethylbenzene synthesized worldwide is used to produce styrene, with smaller amounts used as a solvent or for the production of other chemicals. This article reviews contemporary technologies for the production of ethylbenzene.

 Results. The liquid-phase method of ethylbenzene production using zeolite-containing catalysts for alkylation and transalkylation exhibits the highest efficiency and simplicity. In comparison with liquid-phase alkylation catalysts, e.g., aluminum chloride, zeolitecontaining catalysts demonstrate high activity, selectivity, stability, and resistance to impurities. In addition, they are non-corrosive, environmentally friendly, regenerable, and have a prolonged cycle length between regenerations. More than half of the ethylbenzene synthesized globally is produced by the Badger EBMax process using a catalyst based on zeolite of the MWW family (MCM-22). This technology enables a low benzene to ethylene ratio (from 2.5 to 4), which reduces the benzene circulation rate, increases efficiency, and reduces the column throughput for benzene extraction. The main part of contemporary research in the field of benzene alkylation with ethylene into ethylbenzene is associated with the creation and use of zeolite-containing catalysts, which are solid porous systems containing an active component and a binder. The active component is USY, beta, mordenite, ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-48, MCM-22, and MCM-49 zeolites. Among the preferred alkylation catalysts are Beta zeolite or zeolite of the MCM-22 family. The binder is Al2O3, SiO2, or amorphous aluminosilicate. Current research also focuses on methods for creating zeolite materials with an increased mesoporous surface area by treating the initial zeolite precursor using various technologies, including combinations of acid treatment and surfactant treatment followed by alkaline solution treatment. Contemporary developments in the field of domestic alkylation and transalkylation catalysts for ethylbenzene production are presented.

Conclusions. The production of ethylbenzene and the further development of technologies for obtaining catalysts for its synthesis are highly promising and important directions in Russia. The technology of liquid-phase alkylation in the presence of contemporary highly active zeolite-containing catalysts offers significant advantages. 

Objectives. High-entropy alloys (HEAs) represent a novel class of metallic materials known for their exceptional mechanical and corrosion-resistant properties. This study investigates the effects of equal channel angular pressing (ECAP) on the microstructure, tensile strength, and corrosion behavior of an equiatomic FeNiMnCr alloy.

Methods. The alloy was synthesized via arc melting, homogenized, and subjected to up to four ECAP passes at 400°C. Phase composition was analyzed using X-ray diffraction, while microstructural features were examined using scanning electron microscopy and transmission electron microscopy. Mechanical properties were evaluated based on Vickers microhardness and tensile testing, while corrosion resistance was assessed in a 3.5% NaCl solution using potentiodynamic polarization.

Results. The results indicate a significant grain refinement, an increased hardness and strength (by 1013 MPa), and an improved corrosion resistance of the alloy after ECAP processing.

Conclusions. The study demonstrates that ECAP is an effective method for enhancing the performance of FeNiMnCr HEAs. This makes it promising for use in nuclear energy, medicine, and aerospace industry.