Influence Of Solvent Research Articles

Femtosecond laser-mediated preparation of HfNbTaTiZr refractory high-entropy alloy nanoparticles for photothermal therapy applications: Influence of solvent and fluence

Nanoparticles (NPs) have become popular photothermal therapy (PTT) photosensitizers because they can be targeted to cancer tissues and deliver a chemotherapeutic medication. Pulsed laser ablation in liquid media (PLAL) can produce stable colloidal NPs without any stabilizing agents. The stability, size distribution, and morphology of the produced colloids are influenced by the nature of NPs, laser parameters such as laser power, laser frequency repetition, ablation rate, and the specific ionic effects from the solvent. In this work, HfNbTaTiZr refractory high entropy alloy (RHEA) NPs were prepared by PLAL method in different solvents, including distilled water, ethanol, and n-hexane. The experiments were performed by irradiating a HfNbTaTiZr target with a femtosecond laser outputting 120-fs pulse at varying levels of ablation fluence (0.1, 0.16, 0.23 mJ/cm2). The elemental and structural characteristics of the prepared HfNbTaTiZr NPs were elucidated by using several advanced analytical techniques. The XRD pattern of NPs revealed that the liquid medium significantly affects the type of crystallized phases and the surface composition. The surface composition was studied by XPS, indicating that the fabricated NPs were oxidized. SEM and TEM analysis have evidenced the generation of NPs with an average diameter of less than 50 nm. The results revealed that the higher ablation fluence resulted in the formation of NPs with a larger average diameter. The highest intrinsic photothermal conversion efficiency and 12 °C time-dependent solvent heating produced in ethanol at 640 nm irradiation after 20 min were demonstrated.

Solvent Effect on Small-Molecule Thin Film Formation Deposited Using the Doctor Blade Technique

Small molecule thin films are the core of some organic optoelectronic devices. Their deposition by solution processes is an advantage for device fabrication and can be achieved via spin coating for small areas and slot-die or doctor blade for larger areas. Solution deposition of small molecule thin films is usually processed only with medium polarity solvents. Herein, the use and influence of solvents with several polarities and physicochemical properties to form small-molecule homogeneous thin films via the doctor blade technique over an area of 25 cm2 have been explored. Solvents with different polarity, heptane, chlorobenzene, N,N-dimethylformamide, acetonitrile, and methanol were used along with different deposition temperatures, from room temperature up to near the boiling temperature for each solvent. With heptane and chlorobenzene, smooth films with an average roughness of 3 nm and thickness of 100–120 nm were obtained. The film was homogeneous over the whole substrate for temperatures from room temperature to close to the boiling temperature of both solvents. On the other hand, with dimethylformamide, a film is observed when the deposition is conducted only at room temperature; when the deposition temperature increases, the formation of agglomerates of several sizes from 1 to 5 nm was observed. With acetonitrile, and methanol, no films were formed, and only nanoaggregates were created on the substrate due to the solvent high vapor pressure, and the agglomerate size depends on the deposition temperature. The measure of the contact angle of pure solvent and solutions indicated that wettability helps to film formation over the whole substrate. For heptane and chlorobenzene, a small angle was measured; meanwhile, the contact angle is large in acetonitrile leading to the formation of nanoaggregates. In the case of methanol solution, although it wets very well, no film is deposited because it has high volatility.

Intramolecular interactions (O-H∙∙∙O, C-H∙∙∙N, N-H∙∙∙π) in isomers of neutral, cation, and anion dopamine molecules: A DFT study on the influence of solvents (water and ethanol).

Dopamine (DA) is one of the most important neurotransmitters associated with numerous neural disorders. This investigation reports the intramolecular interactions present in the isomers of neutral (DA0), anionic (DA-), and cationic (DA+) dopamine isomers in gas, water, and ethanol mediums. Neutral and anion isomers have O-H∙∙∙O, C-H∙∙∙N intramolecular hydrogen bonds and N-H∙∙∙π interactions. All the interactions are electrostatic in nature. Isomers of cation dopamine show no intramolecular interactions in the solvent. Natural charges from natural bond orbital (NBO) analysis show that O-H∙∙∙O bonds and the N-H∙∙∙π interactions are the most and least polar, respectively. 1H NMR study reveals the inverse linear correlation between shielding constant and electron density in a solvent medium. HOMO-LUMO energy gap indicates higher stability for neutral and cationic forms of dopamine isomers in water and ethanol medium. We have optimized all the structural forms of dopamine molecule using the Becke three hybrid exchange and Lee-Yang-Parr correlation functional with Grimme's dispersion correction, B3LYP-D3(BJ), and aug-cc-pVTZ basis set using the Gaussian16 software. Vibrational frequency analysis with no imaginary frequencies confirms the nature of global minima. The solvent studies (water and ethanol) were carried out using the SCRF keyword and the polarisable continuum model (PCM) of Miertus and Tomasi. NBO analysis and NMR studies were also performed for all conformers. Topology analysis was explored using the software Multiwfn.

MassChemSite for In-Depth Forced Degradation Analysis of PARP Inhibitors Olaparib, Rucaparib, and Niraparib.

Drugs must satisfy several protocols and tests before being approved for the market. Among them, forced degradation studies aim to evaluate drug stability under stressful conditions in order to predict the formation of harmful degradation products (DPs). Recent advances in LC-MS instrumentation have facilitated the structure elucidation of degradants, although a comprehensive data analysis still represents a bottle-neck due to the massive amount of data that can be easily generated. MassChemSite has been recently described as a promising informatics solution for LC-MS/MS and UV data analysis of forced degradation experiments and for the automated structural identification of DPs. Here, we applied MassChemSite to investigate the forced degradation of three poly(ADP-ribose) polymerase inhibitors (olaparib, rucaparib, and niraparib) under basic, acidic, neutral, and oxidative stress conditions. Samples were analyzed by UHPLC with online DAD coupled to high-resolution mass spectrometry. The kinetic evolution of the reactions and the influence of solvent on the degradation process were also assessed. Our investigation confirmed the formation of three DPs of olaparib and the wide degradation of the drug under the basic condition. Intriguingly, base-catalyzed hydrolysis of olaparib was greater when the content of aprotic-dipolar solvent in the mixture decreased. For the other two compounds, whose stability has been much less studied previously, six new degradants of rucaparib were identified under oxidative degradation, while niraparib emerged as stable under all stress conditions tested.

The impact of solvent selection on the characteristics of niosome nanoparticles prepared by microfluidic mixing

The aim of this work was to assess the impact of solvent selection on the characteristics of niosomes prepared by microfluidic mixing. To achieve this, niosomes were manufactured using bench-scale microfluidic mixing systems by changing the type of aqueous and/or organic solvents used to prepare the particles. Niosomes were prepared using different non-ionic surfactants and cholesterol compositions with different solvents and evaluated to investigate the influence of organic and aqueous solvents on the particle's physiochemical characteristics. Here we demonstrated that the solvent selection is a key factor to be considered during the preparation of niosomes with microfluidic mixing. The type of organic solvent was shown to significantly affect the size and the size distribution of the prepared particles. In general, niosome size increased with increasing organic solvent polarity, without affecting the niosomes stability. Moreover, changing the aqueous solvent used to hydrate the lipid components significantly (p < 0.05) affected the characteristics of the prepared niosomes in terms of particles size, size distribution, and surface charge. This impact of solvent selection on the final product is dependent on the lipid components where niosomes prepared with different compositions will have different characteristics when changing the type of organic and/or aqueous solvents. The apparent encapsulation efficiency of quinine as a model hydrophobic drug was subsequently shown to be significantly (p < 0.05) affected by the type of the organic solvent used to prepare the niosomes, while the impact of the organic solvent had less impact on the apparent encapsulation of atenolol as a model hydrophilic drug.

Solvent effect on structural and optical properties of Titania nanoparticles for pH sensing applications

Herein, solvents i.e., methanol, ethanol, propanol, and butanol-assisted titania nanoparticles (TNPs) are synthesized by low-temperature sol-gel method for pH sensing applications. The influence of solvent on the morphology, roughness, porosity, refractive index, and sensing properties are investigated. The relatively high average roughness 2.5 nm and lower refractive index 1.69 is observed for B-TNPs. The sensitivity of butanol-assisted phenol red encapsulated TNPs is observed 2.32 counts/pH.

Influence of solvent on accelerating deposition time of α-Fe2O3 photoanode via AACVD

The optical and photoelectrochemical (PEC) properties of semiconductors can be manipulated by varying the deposition time and the solvent used. In this work, the study investigates the influence of organic solvent (methanol and ethanol) on accelerating deposition time for the efficient optical and photoelectrochemical performance of the fabricated α-Fe2O3 thin film photoanode below 10 minutes. The α-Fe2O3 film was fabricated via aerosol-assisted chemical vapor deposition (AACVD). The study discovered that the solvent with high polarity enhanced the crystal growth direction of α-Fe2O3 on the (110) orientation. The UV-vis showed that all deposited α-Fe2O3 films exhibit the absorption band in the visible-light region with the estimated energy bandgap of 2.10 eV. Furthermore, the PEC performance exhibited good photoanodic responses with excellent charge transfer behavior and photostability. These findings show that the choice of solvent could influence the rapid deposition time, thus, would be reliable to accelerate the fabrication process of photoelectrochemical water-splitting photoanode.

Synthesis, structural elucidation and optical activity of symmetric Schiff base-functionalized ferrocenes: Synergetic experimental and DFT insights

A number of Schiff base functionalized derivatives (3a-c) was synthesized from the conventional dehydration of ferrocenecarboxaldehyde and diamine precursors in acetonitrile as a solvent at ambient conditions. IR, UV–Vis, elemental analysis, 1H- and 13CNMR were used to elucidate the novel bis-Schiff base compounds. The nature of electronic absorptions was tracked using Time-Dependent Density-Functional Theory (TD-DFT). The molecular electrostatic potential illuminated that the target compounds are sharing relatively akin electronic distributions. In order to determine the electrophilic and nucleophilic sites, surface analysis of the structures was examined for this purpose. These sites are expected to possess an indispensable role to stabilize and robust the structures via typical hydrogen bonding and non-classical CH···π interactions. Type and influence of solvents on absorption spectra were pursued for the selected model (3a), in which aprotic solvents showed negative solvatochromism (more stable ground state), whereas protic solvents delivered positive solvatochromism (more stable excited state). For example, the metal-to-ligand charge transfer band displayed a gradual shift of the λmax (12 nm) when the type of solvent was switched from polar aprotic (ethyl acetate) to polar protic (methanol) due to the formation of hydrogen bonding, causing bathochromic shift. Eventually, the computationally resulting energy gap of the new products (ΔE) were found to be −4.258 (3a), −4.022 (3b) and −3.105 (3c) eV. These values were compared and found to be in a close level with produced figures from the spectra of density of states and with experimentally determined values using Tauc approach.

Semisynthetic Sesquiterpene Lactones Generated by the Sensibility of Glaucolide B to Lewis and Brønsted-Lowry Acids and Bases: Cytotoxicity and Anti-Inflammatory Activities.

Sesquiterpene lactone (SL) subtypes including hirsutinolide and cadinanolide have a controversial genesis. Metabolites of these classes are either described as natural products or as artifacts produced via the influence of solvents, chromatographic mobile phases, and adsorbents used in phytochemical studies. Based on this divergence, and to better understand the sensibility of these metabolites, different pH conditions were used to prepare semisynthetic SLs and evaluate the anti-inflammatory and antiproliferative activities. Therefore, glaucolide B (1) was treated with various Brønsted-Lowry and Lewis acids and bases-the same approach was applied to some of its derivatives-allowing us to obtain 14 semisynthetic SL derivatives, 10 of which are hereby reported for the first time. Hirsutinolide derivatives 7a (CC50 = 5.0 µM; SI = 2.5) and 7b (CC50 = 11.2 µM; SI = 2.5) and the germacranolide derivative 8a (CC50 = 3.1 µM; SI = 3.0) revealed significant cytotoxic activity and selectivity against human melanoma SK-MEL-28 cells when compared with that against non-tumoral HUVEC cells. Additionally, compounds 7a and 7c.1 showed strongly reduced interleukin-6 (IL-6) and nitrite (NOx) release in pre-treated M1 macrophages J774A.1 when stimulated with lipopolysaccharide. Despite the fact that hirsutinolide and cadinanolide SLs may be produced via plant metabolism, this study shows that acidic and alkaline extraction and solid-phase purification processes can promote their formation.

Computational study of the alcoholysis for organophosphorus pesticides: The reaction of phoxim with methanol

The alcoholysis process for one of organophosphorus pesticides, phoxim, was systematically examined by using the M06-2X/6–311++G(d,p) and MP2/6–311++G(d,p)//M06-2X/6–311++G(d,p) levels. Two possible alcoholysis mechanisms, P–OR1, P–OEt rupture channels together with the concerted and stepwise steps, were theoretically evaluated. The catalytic role of an extra methanol was also simulated. Furthermore, the influence of solvent on water was also taken into consideration for the M06-2X/6–311++G(d,p) level of theory. Our predicted results show convincingly that the P–OEt disintegration pathway is slightly more favorable than the P–OR removal channel. The stepwise pathway is calculated to be more prominent than the concerted one for all reactions. It can be observed that the methanol-assisted alcoholysis is more easier to take place than the direct alcoholysis. Solvent effect does not have remarkable effect on the reaction mechanism.

Chiral and Morphological Anisotropy of Supramolecular Polymers Shaped by a Singularity in Solvent Composition.

Understanding the role of solvent in translating molecular anisotropy to supramolecular polymers is in the early stages. A solvent's influence on the strength of different noncovalent interactions can explain anisotropic growth in some cases, but its effect on cooperative processes, particularly in mixed solvents, remains obscure. We report the self-assembly of a series of chiral perylene bisimides in water-cosolvent mixtures, and the results highlight the fascinating influence of solvent-solute interactions on supramolecular anisotropy, both chiral and morphological. The initial assembly is agnostic to solvent composition, resulting in weakly chiral, spherical nanostructures. In an extremely narrow solvent composition range, the nanospheres transform into long, prominently chiral supramolecular polymers. Further, chirality can be fully reversed by changing the good (achiral) cosolvent. We elucidate how solvent modulates specific noncovalent interactions and governs the kinetics and thermodynamics of key processes, such as spontaneous phase segregation, secondary nucleation, and cooperative growth. In the context of supramolecular polymerization, our results encourage one to steer the focus away from the physical attributes of a solvent (polarity, phase diagram, etc.) and toward the complexities of solvent-solute interactions.

Effects of Soaking, Cooking, and Steaming Treatments on the Faba Bean Seeds’ Total Bioactive Compounds Content and Antioxidant Activity

Faba bean (Vicia faba L.) is a winter-sowing grain legume with high-protein content utilized for human consumption and animal feeding. Faba beans contain high levels of polyphenol compounds with various nutritional benefits. Legume seeds, such as faba beans, are subject to different processing procedures before consumption, which decreases the levels of their bioactive compounds (polyphenols and flavonoids), resulting in a reduction in antioxidant activity. This study aimed to examine the influence of soaking, cooking, and steaming treatments on the total polyphenols, total flavonoid, and antioxidant activity levels of Broad (large) and Field (small) faba beans. Initially, the influence of the different extraction solvents on total phenolic content (TPC), total flavonoid content (TFC), and ferric reduction ability of plasma antioxidant activity (FRAP), variables were inspected, wherein the extraction efficiency. 70% acidic acetone treatment was found to be the best solvent for extraction. Then, we determined the soaking, cooking, and steaming effects on TPC, TFC, and FRAP levels compared to dry seeds as the control. It was found that the various processes resulted in a significant reduction in the level of these components in the processed seeds of both Broad and Field beans. Nevertheless, the soaking treatment resulted in the smallest reduction. In addition, steaming caused a more moderate decline among the cooking types. Therefore, to maintain a higher level of these three ingredients in the final product, it is better to steam the seeds than cook them.

Anisole Hydrodeoxygenation over Nickel-Based Catalysts: Influences of Solvent and Support Properties

The realization of biofuels and chemicals requires the development of highly active and selective catalysts, which are resistant to deactivation. A conventional ZSM-5 (SiO2/Al2O3 = 30) was modified with 0.2 M NaOH to generate a mesoporous zeolite support. The parent zeolite, mic-ZSM-5, the modified zeolite, hie-ZSM-5, and a mesoporous silica support, SiO2, were impregnated with 5% nickel and characterized using X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis of nitrogen sorption, scanning electron microscopy with energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonium hydrogen temperature-programmed desorption (NH3-TPD), and thermogravimetric analysis (TGA). The influences of the support properties and solvent during the hydrodeoxygenation of anisole were investigated by measuring concentration profiles and rates in a high-pressure batch reactor. NaOH treatment significantly improved the pore structure, acidity of the support, and metal dispersion as well as the interaction of nonframework Ni species with zeolite and, hence, the catalytic activity and selectivity. The highest anisole conversion of 100% was obtained in 120 min over the hie-Ni/ZSM-5 catalyst with cyclohexane selectivity of 88.1%. In addition, the Ni/SiO2 catalyst was 84.5% selective to toluene at 48.9% anisole conversion in 120 min; as such, it was proposed that the transformation of anisole proceeds via either a direct deoxygenation–hydrogenation or isomerization–direct deoxygenation pathway. However, no substantial differences in anisole conversion or product selectivity were observed when decalin and n-decane were compared as solvents. A catalyst reusability test showed hie-Ni/ZSM-5 as the most stable of the three catalysts in terms of anisole transformation, even though the catalyst recorded the biggest weight loss of 9.2% suggesting high resistance to carbon deactivation. Therefore, with this very good catalytic activity, good selectivity to liquid product, and stability, the mesoporous Ni/ZSM-5 catalyst is a potential candidate for economically beneficial future industrial applications.

Solvent Influence on the Magnetization and Phase of Fe-Ni Alloy Nanoparticles Generated by Laser Ablation in Liquids.

The synthesis of bimetallic iron-nickel nanoparticles with control over the synthesized phases, particle size, surface chemistry, and oxidation level remains a challenge that limits the application of these nanoparticles. Pulsed laser ablation in liquid allows the properties tuning of the generated nanoparticles by changing the ablation solvent. Organic solvents such as acetone can minimize nanoparticle oxidation. Yet, economical laboratory and technical grade solvents that allow cost-effective production of FeNi nanoparticles contain water impurities, which are a potential source of oxidation. Here, we investigated the influence of water impurities in acetone on the properties of FeNi nanoparticles generated by pulsed laser ablation in liquids. To remove water impurities and produce "dried acetone", cost-effective and reusable molecular sieves (3 Å) are employed. The results show that the Fe50Ni50 nanoparticles' properties are influenced by the water content of the solvent. The metastable HCP FeNi phase is found in NPs prepared in acetone, while only the FCC phase is observed in NPs formed in water. Mössbauer spectroscopy revealed that the FeNi nanoparticles oxidation in dried acetone is reduced by 8% compared to acetone. The high-field magnetization of Fe50Ni50 nanoparticles in water is the highest, 68 Am2/kg, followed by the nanoparticles obtained after ablation in acetone without water impurities, 59 Am2/kg, and acetone, 52 Am2/kg. The core-shell structures formed in these three liquids are also distinctive, demonstrating that a core-shell structure with an outer oxide layer is formed in water, while carbon external layers are obtained in acetone without water impurity. The results confirm that the size, structure, phase, and oxidation of FeNi nanoparticles produced by pulsed laser ablation in liquids can be modified by changing the solvent or just reducing the water impurities in the organic solvent.

The effect of solvent on determining highest occupied molecular orbital energies of semiconducting organic molecules: Insight from a combined computational approach.

Although cyclic voltammetry (CV) measurements in solution have been widely used to determine the highest occupied molecular orbital energy (EHOMO ) of semiconducting organic molecules, an understanding of the experimentally observed discrepancies due to the solvent used is lacking. To explain these differences, we investigate the solvent effects on EHOMO by combining density functional theory and molecular dynamics calculations for four donor molecules with a common backbone moiety. We compare the experimental EHOMO values to the calculated values obtained from either implicit or first solvation shell theories. We find that the first solvation shell method can capture the EHOMO variation arising from the functional groups in solution, unlike the implicit method. We further applied the first solvation shell method to other semiconducting organic molecules measured in solutions for different solvents. We find that the EHOMO obtained using an implicit method is insensitive to solvent choice. The first solvation shell, however, produces EHOMO values that are sensitive to solvent choices and agrees with published experimental results. The solvent sensitivity arises from a hierarchy of three effects: (1) the solute electronic state within a surrounding dielectric continuum, (2) ambient temperature or solvent atoms changing the solute geometry, and (3) electronic interactions between the solute and solvents. The implicit method, on the other hand, only captures the effect of a dielectric environment. Our findings suggest that EHOMO obtained by CV measurements should account for the influence of solvent when the results are reported, interpreted, or compared to other molecules.

Heterogenised catalysts for the H-transfer reduction reaction of aldehydes: influence of solvent and solvation effects on reaction performances.

Heterogenisation of homogeneous catalysts onto solid supports represents a potential strategy to make the homogeneous catalytic function recyclable and reuseable. Yet, it is usually the case that immobilised catalysts have much lower catalytic activity than their homogeneous counterpart. In addition, the presence of a solid interface introduces a higher degree of complexity by modulating solid/fluid interactions, which can often influence adsorption properties of solvents and reactive species and, ultimately, catalytic activity. In this work, the influence of support and solvent in the H-transfer reduction of propionaldehyde over Al(OiPr)3-SiO2, Al(OiPr)3-TiO2 and Al(OiPr)3-Al2O3 heterogenised catalysts has been studied. Reaction studies are coupled with both NMR relaxation measurements as well as molecular dynamics (MD) simulations in order to unravel surface and solvation effects during the reaction. The results show that, whilst the choice of the support does not influence significantly catalytic activity, reactions carried out in solvents with high affinity for the catalyst surface, or able to hinder access to active sites due to solvation effects, have a lower activity. MD calculations provide key insights into bulk solvation effects involved in such reactions, which are thought to play an important role in determining the catalytic behaviour. The activity of the heterogenised catalysts was found to be comparable with that of the homogeneous Al(OiPr)3 catalysts for all supports used, showing that for the type of reaction studied immobilisation of the homogeneous catalyst onto solid supports is a viable, robust and effective strategy.

The influence of solvents on the appearance of the absorption bands of the polystyrene films deposited from solutions on metal mirrors

Infrared reflection-absorption spectra (IRRAS) at the near-normal incidence of polystyrene films from benzene, toluene, and chloroform solutions were analyzed in this paper. The appearance of the spectrum can be affected so that false conclusions can be drawn about the positions and the shape of the absorption bands. The knowledge of these influences of residual solvents in the polymer film is important for the correct interpretation of the reflection-absorption spectra. Unlike other approaches, a single reflection at a 20° incidence angle was used. A new drop-carting technique was used for the deposition of polymer film solutions on metal mirrors. Reflection-absorption spectra at a near-normal incidence angle were obtained using a dispersive infrared spectrometer.

Influence of solvent choice and operating conditions on Chlorzoxazone crystal shape and size

Solubility of pharmaceutical drugs in organic solvents is one of the important parameters to understand the equilibrium concentration of solute-solvent, which helps optimize and design crystallization conditions to obtain the desired product crystals. In the present study, Chlorzoxazone (CHZ) is used as a model pharmaceutical compound to investigate the equilibrium solubility, the influence of solvent and the operating conditions on the shape, and the size distribution. The solubility of CHZ is determined in organic solvents like Isopropanol, Ethanol, and 2-Ethoxyethylacetate, Ethylacetate and Ethyllactate using shake flask method from -5ºC to 60ºC. The solubility of CHZ in these solvents shows an increasing trend as the temperature increases in the following order: ethyllactate + water (0.5+0.5) < ethylacetate < isopropanol < ethanol < 2-ethoxyethylacetate < ethyllactate + water (0.75+0.25). The solvents, isopropanol, ethanol, and ethyl lactate, produce needle-shaped crystals, while 2-ethoxyethylacetate and ethyl acetate tend to produce plate shaped crystals. CHZ crystals obtained from 2-ethoxyethylacetate tend to have plate shaped crystals with a lower aspect ratio and are selected for batch cooling crystallization experiments performed at different cooling rates, and agitation. It is found that the agitation at 300 rpm and the cooling rate 0.2ºC/min produce more uniform crystal size distribution.

Дослідження екстракційного розділення бензинових фракцій, одержаних внаслідок піролізу вживаних шин.

In recent years, the high demand for energy resources and environmental degradation have been pressing issues faced by humanity due to the over-exploitation and use of fossil fuels. With the increasing environmental awareness of the population, technologies for the reuse of waste, including waste tires, deserve special attention, which in turn allows to reduce the negative impact on the environment, maximize resource utilization and reduce dependence on fossil fuels. In this work, we analyze the process of extraction separation of the fraction boiling above 200°C to remove aromatic and unsaturated compounds obtained as a result of the pyrolysis process of used tires at a small pilot plant. Two solvents, N-methylpyrrolidone and diethylene glycol (DEG), were used in the extraction separation of the fraction boiling above 200 °C. The volume ratios of raw materials to solvent were chosen as follows: 1:0.5, 1:1, 1:1.5, and 1:2 for N-methylpyrrolidone, and 1:5, 1:10, 1:15, and 1:20 for DEG, respectively. As a result of the studies, the influence of solvents on the physicochemical properties of the obtained products was determined. It has been proved that the best physicochemical properties are characterized by the raffinates and extracts obtained at a volume ratio of raw materials to solvent of 1:2.0 in the presence of N-methylpyrrolidone, and 1:20 in the presence of DEG. It was found that the use of N-methylpyrrolidone in a ratio of 1:2 resulted in a decrease in the density and bromine number of the refined product by 2.64 % and 10.79 % compared to the initial fraction, respectively, and the use of DEG in a ratio of 1:20 resulted in a decrease in the density and bromine number of the refined product by 1.44 % and 12.06 % compared to the initial fraction, respectively. Further ways of using the obtained products of the extraction separation process of the gasoline fraction at a boiling above 200 °C are proposed. Keywords: used tires, waste tires, tire pyrolysis, gasoline, fraction, extraction separation. Corresponding author: B.O. Korchak, e-mail: kor4ak93@gmail.com

Influence of solvent on the electronic structure and the photochemistry of nitrophenols

Photochemistry of nitroaromatics in organic solvents can vary significantly from the photochemistry in aqueous solutions.