Free OH Research Articles

The Fate of the Formic Acid Proton on the Anatase TiO2(101) Surface

AbstractAs a prototype adsorption reaction of gas Brønsted acid on oxides, we study the adsorption of formic acid on anatase. We perform infrared spectroscopy measurements of adsorbed HCOOH and HCOOD on TiO2 nanopowders, from 13 K up to room temperature in an ultra‐high vacuum chamber. We assign the IR signals via computed spectra from nuclear quantum dynamics simulations using our divide‐and‐conquer semiclassical ab initio molecular dynamics method. The acid proton forms an extraordinarily short and strong hydrogen bond with the surface oxygen. The strength of this hydrogen bond, that compares to H bonds in ice at high pressures, is at the root of a substantial redshift with respect to the typical free OH stretching frequency, which eludes its straightforward detection.

Revisiting the Thickness of the Air-Water Interface from Two Extremes of Interface Hydrogen Bond Dynamics.

The air-water interface plays a crucial role in many aspects of science because of its unique properties, such as a two-dimensional hydrogen bond (HB) network and completely different HB dynamics compared to bulk water. However, accurately determining the boundary of interfacial and bulk water, that is, the thickness of the air-water interface, still challenges experimentalists. Various simulation-based methods have been developed to estimate the thickness, converging on a range of approximately 3-10 (Å). In this study, we introduce a novel approach, grounded in density functional theory-based molecular dynamics and deep potential molecular dynamics simulations, to measure the air-water interface thickness, offering a different perspective based on prior research. To capture realistic HB dynamics in the air-water interface, two extreme scenarios of the interface HB dynamics are obtained: one underestimates the interface HB dynamics, while the other overestimates it. Surprisingly, our results suggest that the interface HB dynamics in both scenarios converges as the thickness of the air-water interface increases to 4 (Å). This convergence point, indicative of the realistic interface thickness, is also validated by our calculation of anisotropic decay of OH stretch and the free OH dynamics at the air-water interface.

In-situ manganese-aluminum-iron biochar derived from waste flocs for enhanced peroxymonosulfate oxidation: Role of Fe/Mn drives active species based on aluminum adsorption and synergistic promoted electron transfer

Conventional coagulation or enhanced coagulation water treatment produced mass floc sludge, which contained plenty of metals and organic matter. Floc sludge disposal and resource recycling was vital relevance and urgently needed. Here, we reported on the waste flocs recycling through in-situ manganese-aluminum-iron biochar (MAFBC) synthesized via one-step pyrolysis using potassium permanganate (KMnO4) oxidation- aluminum-iron composite flocculant coagulation for humic acid removal floc sludge as raw material. Compared with ex-situ loaded or similar types of biochar, MAFBC showed faster and efficient activation effect of peroxymonosulfate (PMS) to degrade tetracycline (TC). TC was rapidly removed within 1 min in MAFBC/PMS system with degradation rate constant Kobs was 1.825 min−1, which mainly attributed to the multiple promoting effects of manganese-aluminum-iron. Aluminum oxides facilitated TC adsorption and synergistic Fe/Mn further significantly promoted electron transfer on the surface of the MAFBC. Additionally, bimetallic structure of Fe/Mn and the CO functional group on MAFBC accelerated the formation of reactive species. The redox cycles of Fe2+/Fe3+ and Mn2+/Mn3+/Mn4+ promoted the formation of free radicals OH and SO4−. Moreover, O2– and 1O2 also assumed an important role for TC removal during active species evolution drived by Fe/Mn. This research provides a new perspective for in-situ design of economical and stable metal carbon-based water treatment activator, and make contributions to the utilization of waste flocs in water treatment.

Reactive Molecular Dynamics Simulations of Micrometeoroid Bombardment for Space Weathering of Asteroid (162173) Ryugu

Remote sensing observations by Hayabusa2 and laboratory measurements have revealed that the phyllosilicates on asteroid (162173) Ryugu are dehydrated/dehydroxylated due to space weathering. Reactive molecular dynamics simulations were performed to evaluate the magnitude of the dehydroxylation of Mg-rich serpentine by micrometeoroid impacts. When micrometeoroids were not coupled with interplanetary magnetic fields, serpentine could be dehydroxylated by micrometeoroids as small as 2 nm in size. In particular, ∼200 O–H bonds dissociated when the meteoroids were derived from cometary activity (the impact velocity was ∼20 km s−1). When nano-sized dust particles were accelerated to ∼300 km s−1 by the magnetic fields of solar wind plasma, the number of dissociated O–H bonds increased by 1 order of magnitude. Consequently, even 1 nm-sized dust particles can contribute to the space weathering of Ryugu. In all cases, Si–OH, H2O, and free OH were generated from the hydroxyls initially connected to Mg, which could partially offset dehydration. Despite the limitations of our computational resources, which restricted the simulation timescale to 1 ps, reactive molecular dynamic simulations demonstrated that micrometeoroid bombardment could influence the space weathering of asteroids.

The Fate of the Formic Acid Proton on the Anatase TiO2(101) Surface.

As a prototype adsorption reaction of gas Brønsted acid on oxides, we study the adsorption of formic acid on anatase. We perform infrared spectroscopy measurements of adsorbed HCOOH and HCOOD on TiO2 nanopowders, from 13 K up to room temperature in an ultra-high vacuum chamber. We assign the IR signals via computed spectra from nuclear quantum dynamics simulations using our divide-and-conquer semiclassical ab initio molecular dynamics method. The acid proton forms an extraordinarily short and strong hydrogen bond with the surface oxygen. The strength of this hydrogen bond, that compares to H bonds in ice at high pressures, is at the root of a substantial redshift with respect to the typical free OH stretching frequency, which eludes its straightforward detection.

Catalyst-free selective oxidation of C(sp3)-H bonds in toluene on water

The anisotropic water interfaces provide an environment to drive various chemical reactions not seen in bulk solutions. However, catalytic reactions by the aqueous interfaces are still in their infancy, with the emphasis being on the reaction rate acceleration on water. Here, we report that the oil-water interface activates and oxidizes C(sp3)-H bonds in toluene, yielding benzaldehyde with high selectivity (>99%) and conversion (>99%) under mild, catalyst-free conditions. Collision at the interface between oil-dissolved toluene and hydroxyl radicals spontaneously generated near the water-side interfaces is responsible for the unexpectedly high selectivity. Protrusion of free OH groups from interfacial water destabilizes the transition state of the OH-addition by forming π-hydrogen bonds with toluene, while the H-abstraction remains unchanged to effectively activate C(sp3)-H bonds. Moreover, the exposed free OH groups form hydrogen bonds with the produced benzaldehyde, suppressing it from being overoxidized. Our investigation shows that the oil-water interface has considerable promise for chemoselective redox reactions on water without any catalysts.

Soft confinement of water in aliphatic alcohols: MIR/NIR spectroscopic and DFT studies

Here, we present the first examination of the state of water under a soft confinement in eight aliphatic alcohols including cyclopentanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-decanol, 2-octanol and 3-octanol. Due to relatively large size of the aliphatic part, water has limited solubility in all studied alcohols. Water content in saturated solutions was determined by Karl Fischer titration and correlated with the spectroscopic data. This way, we determined the molar absorptivity of the ν2+ν3 combination mode. The effect of addition of water and temperature variation was monitored by ATR-IR and NIR spectroscopy. Analysis of the experimental results was guided by DFT calculations, which provided the structures, harmonic MIR spectra and binding energies of selected alcohol-water complexes.Our studies demonstrated that the state of water in alcohols is related to its solubility, which depends on structure of solvent molecules. The solubility of water in 1-alcohols decreases on increasing of the chain length, but for long chain alcohols this effect is less evident. More apparent solubility reduction appears in going from the primary to secondary alcohols. The effective shielding of the OH group in the linear alcohols is achieved when on both sides of the OH group are ethyl or longer substituents, while the shielding by methyl groups is less efficient. Water is much better soluble in the cyclic alcohols as compared with the linear ones due to better accessibility of the OH group.The soft confinement of water in aliphatic alcohols allows for flexible structural arrangements and interactions. Even at low water content, we did not observe free molecules of water. At these conditions, the molecules of water are singly or doubly bonded to the OH groups from the alcohol. Increasing solubility of water reduces the number of the free OH groups and leads to formation of water clusters. Obtained results allow concluding that in alcohols with sizable aliphatic part the molecules of water are confined in the vicinity of the OH groups.

THE METHOD OF QUANTITATIVE DETERMINATION OF THE AMOUNT OF FLAVONOIDS IN THE FLOWERS OF GIANT CEPHALARIA

Giant cephalaria (Cephalaria gigantea (LEDEB.) BOBROV) is a powerful perennial whose height reaches two meters. This plant is found in Southern Europe, Western and Central Asia, as well as in North and South Africa. It is cultivated in the Botanical garden of Samara University. The extracts of giant cephalaria have been used in traditional medicine for many years due to their antimicrobial, antifungal, cytotoxic, antioxidant, antidiabetic and antipyretic activities, which may be due to various biologically active compounds. It is known that the leaves contain triterpenoids, phenolic carboxylic acids and their derivatives, flavonoids, and the flowers contain flavonoid compounds: luteolin, quercetin, cynaroside, quercimeritrin and gigantoside A. The article describes the development of a technique for quantifying of the amount of flavonoids in the flowers of giant cephalaria. Spectrophotometric analysis of water-alcohol extracts from giant cephalaria flowers allowed us to establish that the main contribution to the absorption curve of their UV-spectra in the presence of AlCl3 is made by flavonols having a free OH group at the C-3 position, and in the differential version, the maximum absorption of the tested solution is close to that of the standard sample of quercetin (428±2 nm). Optimal conditions for the extraction of flavonoids in giant cephalaria flowers were determined: extractant 70% ethyl alcohol; the ratio "raw material-extractant" – 1 : 50; extraction time – extraction in a boiling water bath for 60 minutes, the degree of grinding of raw materials – 2 mm, analytical wavelength – 426 nm. It was determined that the content of the total flavonoids calculated on quercetin in the flowers of giant cephalaria varies from 1.58±0.05% to 2.63±0.05%. The error of a single determination with a 95% confidence probability is ±1.75%. The obtained results were used in the development of the FS project for a new type of medicinal plant raw materials "Cephalaria giant flowers" for introduction into the State Pharmacopoeia of the Russian Federation.

Influence of surfactant adsorption on coal oxidation and wettability: Experimental discussion and model development

To further investigate the physicochemical properties and wettability changes of surfactant-modified coal after oxidation, the contact angle, industrial composition, and functional groups of the surfactant-modified coal were measured. The experimental data were analyzed using a ridge regression prediction model to explore the relationship between the physicochemical properties and the wettability. The results indicate that the oxidated-modified coal has a worse wettability at room temperature. The adsorption of SL and CDEA surfactants effectively impedes the increase in the contact angle of the oxidized coal. The hydrophilic functional group (2#CO, C–O–C, RHCCH2) in coal demonstrates higher sensitivity to surfactants, while the hydrophobic functional group (2# Free OH, 1#CC) exhibits greater reactivity. There is a strong correlation between the industrial composition, structural parameters, and the contact angle. The quantitative influence of the parameters on the contact angle is as follows: FCad > Vad > P1 ≥ P4 ≥ Mad ≥ P3 ≥ P2. A coal wetting model is established that considers the combined action of surfactants and coal quality. These findings suggest that wettability is determined by multiple parameters, providing a basis for discovering new reagents that significantly enhance coal wettability and reduce coal oxidation activity.

Analyzing moisture diffusion in the interface between rubber-modified asphalt and aggregate: A 3D study considering multiple influencing factors

Moisture erosion is inevitable at the interface between rubber-modified asphalt and aggregate. When moisture penetrates the interface through diffusion, it causes varying degrees of damage. In this study, molecular simulation technology was used to simulate the moisture diffusion interface considering multiple influencing factors. The radial distribution function (RDF), mean square displacement (MSD), and relative concentration profile (RCP) were calculated to evaluate the moisture diffusion direction. Density functional theory was employed to measure the interaction between rubber-modified asphalt components and H2O molecules, and the moisture-damaged areas were analyzed using crystal orbital populations, which can obtain three-dimensional (3D) diffusion mechanism. The results demonstrated that the remaining free H+ ions interacted with the aromatic ring and CC (double bond) in the rubber. Under the effects of multiple factors such as loading and temperature conditions, moisture permeates the rubber-modified asphalt and aggregate interface, resulting in overall degradation of the composition. Furthermore, the hydrogen atoms in the free OH- groups attract the more polar heteroatoms surrounding them.

Ion Spectroscopy Reveals Structural Difference for Proteins Microhydrated by Retention and Condensation of Water.

Protein ubiquitin in its +7 charge state microhydrated by 5 and 10 water molecules has been interrogated in the gas phase by cold ion UV/IR spectroscopy. The complexes were formed either by condensing water onto the unfolded bare proteins in a temperature-controlled ion trap or by incomplete dehydration of the folded proteins. In the case of cryogenic condensation, the UV spectra of the complexes exhibit a resolved vibrational structure, which looks similar to the spectrum of bare unfolded ubiquitin. The spectra become, however, broad-band with no structure when complexes of the same size are produced by incomplete dehydration under soft conditions of electrospray ionization. We attribute this spectroscopic dissimilarity to the structural difference of the protein: condensing a few water molecules cannot refold the gas-phase structure of the bare ubiquitin, while the retained water preserves its solution-like folded motif through evaporative cooling. This assessment is firmly confirmed by IR spectroscopy, which reveals the presence of free NH and carboxylic OH stretching vibrations only in the complexes with condensed water.

A Photocatalytic Approach for the Synthesis of L‐Shape Bicyclic NHC Ligands

AbstractL‐shape N‐Heterocyclic Carbenes (NHCs) based on the imidazo[1,5‐a]pyridine (ImPy) scaffold have recently gained considerable interest as the true carbene ligand analogues of the popular dialkylbiarylphosphines, better known as Buchwald phosphines. Nevertheless, the substitution pattern of ImPy ligands is still rather limited due to synthetic access issues. We report herein an efficient and versatile visible light photocatalytic strategy to access L‐shape bifunctional ImPy ligands laterally‐functionalized by a phenol group. Mechanistic investigations supported by density functional theory (DFT) reveal that the excited state of the iridium photocatalyst undergoes either a reductive quenching (SET process) or an energy‐transfer quenching (EnT process) depending on the nature of the counterion of the 5‐bromoimidazo[1,5‐a]pyridinium substrate salt. Moreover, the bifunctional character of these new family of L‐shape ImPy ligands is demonstrated by the preparation of a gold(I) complex exhibiting a free OH function capable of intermolecular hydrogen bonding. This work highlights the advantage of visible light photocatalysis in the synthesis of advanced NHC ligand structures, a strategy that has not yet been considered despite its potential benefits in terms of versatility, diversity and practicability.

Unified picture of vibrational relaxation of OH stretch at the air/water interface

The elucidation of the energy dissipation process is crucial for understanding various phenomena occurring in nature. Yet, the vibrational relaxation and its timescale at the water interface, where the hydrogen-bonding network is truncated, are not well understood and are still under debate. In the present study, we focus on the OH stretch of interfacial water at the air/water interface and investigate its vibrational relaxation by femtosecond time-resolved, heterodyne-detected vibrational sum-frequency generation (TR-HD-VSFG) spectroscopy. The temporal change of the vibrationally excited hydrogen-bonded (HB) OH stretch band (ν=1→2 transition) is measured, enabling us to determine reliable vibrational relaxation (T1) time. The T1 times obtained with direct excitations of HB OH stretch are 0.2-0.4 ps, which are similar to the T1 time in bulk water and do not noticeably change with the excitation frequency. It suggests that vibrational relaxation of the interfacial HB OH proceeds predominantly with the intramolecular relaxation mechanism as in the case of bulk water. The delayed rise and following decay of the excited-state HB OH band are observed with excitation of free OH stretch, indicating conversion from excited free OH to excited HB OH (~0.9 ps) followed by relaxation to low-frequency vibrations (~0.3 ps). This study provides a complete set of the T1 time of the interfacial OH stretch and presents a unified picture of its vibrational relaxation at the air/water interface.

Regulating Microstructure and Macroscopic Properties in Saturated Salt Solutions Containing Disordered Anions and Cations by Magnetic Field.

Saturated aqueous salt solutions have diverse applications in food production, mineral processing, pharmaceuticals, and environmental monitoring. However, the random and disordered arrangement of ions in these solutions poses limitations across different fields. In this study, we employ magnetic fields to regulate the disordered arrangement by a comprehensive methodology combining contact angle measurement, Raman spectroscopy, X-ray diffraction, and molecular dynamics simulations on saturated KCl solutions. Our findings reveal that weak magnetic fields impede the formation of K-Cl contact pairs and disrupt hydrogen bond networks, particularly DDAA and free OH types. However, they facilitate the interaction between water molecules and ions, leading to an increase in the number of K-O and Cl-H contact pairs, along with an expansion in ion hydration radius. These changes affect macroscopic properties, including the interaction with solid substrates and potential solubility increases. Our experimental and simulation results mutually validate each other, contributing to a theoretical framework for studying magnetic field-material interactions.

Tunneling splittings in the vibrationally excited states of water trimer.

Tunneling splitting (TS) patterns in vibrationally excited states of the water trimer are calculated, taking into account six tunneling pathways that describe the flips of free OH bonds and five bifurcation mechanisms that break and reform hydrogen bonds in the trimer ring. A tunneling matrix (TM) model is used to derive the energy shifts due to tunneling in terms of the six distinct TM elements in symbolic form. TM elements are calculated using the recently-developed modified WKB (Wentzel-Kramers-Brillouin) method in full dimensionality. Convergence was achieved for the lowest six excited vibrational modes. Bifurcation widths of the pseudorotational quartets are shown to be of comparable size to the ground-state widths, obtained using instanton theory, or increased for some particular modes of vibration. The largest increase is obtained for the excited out-of-phase flip of two adjacent water monomers with free OH bonds pointing in opposite directions relative to the ring plane. Bifurcation widths in (D2O)3 are found to be two orders of magnitude smaller than in (H2O)3. Geometrical arguments were used to explain the order of states in some TS multiplets in vibrationally excited water trimers.

Conformational adaptation and large amplitude motions of 1-phenyl-2,2,2-trifluoroethanol with two water molecules: a rotational spectroscopic and ab initio investigation.

The 1 : 2 adduct of 1-phenyl-2,2,2-trifluoroethanol (PhTFE), a chiral fluoroalcohol, with two water molecules (PhTFE⋯2H2O) was investigated via chirped pulse Fourier-transform microwave (CP-FTMW) spectroscopy and theoretical calculations. A systematic search of the PhTFE⋯2H2O conformational landscape identified 38 stable minima at the B3LYP-D3BJ/def2-TZVPPD level of theory, 27 of which are within an energy window of 10 kJ mol-1 after applying zero-point energy corrections. Rotational spectra of a single PhTFE⋯2H2O conformer along with eight deuterated and three oxygen-18 isotopologues were assigned. Interestingly, the observed PhTFE⋯2H2O conformer contains PhTFE II, the second most stable monomer conformer, and the most stable PhTFE I dihydrate is ca. 4 kJ mol-1 higher in energy. In contrast, PhTFE I⋯H2O was identified experimentally and theoretically as the most stable 1 : 1 conformer. Furthermore, the observed dihydrate structure experiences large amplitude motions connecting three theoretical minima which differ only in which water oxygen lone pairs are involved in the hydrogen-bonds, i.e., the free OH pointing directions. Additionally, the ortho and para-H2O tunnelling splittings were detected and attributed to the interchange water hydrogen atoms which interact with the aromatic part of PhTFE but not for the water interacting with PhTFE hydroxy group. Extensive theoretical modelling was carried out to gain insight into the associated large amplitude motions including tunnelling, supported by the experimental isotopic and tunnelling splitting data.

Deterioration of bond performance between BFRP bars and coral aggregate concrete incorporating slag-based geopolymers under seawater corrosion environments

The utilization of durable geopolymers instead of ordinary Portland cement (OPC) for developing geopolymer-based seawater coral aggregated concrete (GPCAC) in coastal constructions contributed to the improved marine resource utilization and the reduced CO2 emissions and construction costs. Thus, this study investigated the durability of GPCAC and its bond performance with basalt fiber-reinforced polymer (BFRP) bars under seawater drying-wetting cycles, and cement-based CAC was also selected as a comparison. The bond characteristics and degradation mechanisms of slag-based GPCAC and cement-based CAC specimens were compared and analyzed under different seawater exposure condition. Experimental results revealed that both GPCAC and CAC specimens demonstrated various degrees of degradation in bond strength, whereas their initial bond stiffness exhibited a slight increase owing to the hygroscopic expansion of the superficial epoxy resin of BFRP bars, after being exposed to seawater environmental attacks. This degraded bond strength was primarily attributed to the existence of corrosive ions (i.e., SO42-, Mg2+, and Cl-) in seawater and free OH- in concrete capillary pores. These compounds chemically reacted with the slurry hydration products and the resin matrix, which resulted in the decreasing of concrete strength, the hydrolysis of the resin matrix, the deterioration of fibers, and fiber-resin interface debonding. Compared with CAC specimens, GPCAC specimens achieved better resistance to seawater attacks owing to the more dense and stable reaction products formed by geopolymers compared to OPC. After being subjected to 60 °C seawater attacks for 12 months, approximately 4.9% and 12.0% reductions in the bond strength were reported for GPCAC and CAC specimens, respectively. Finally, the residual bond strength of both GPCAC and CAC specimens was predicted after being served in seawater erosion conditions for 50 years.

A simple strategy passivating ZnO electron transport layers for realizing high efficiency in organic solar cells

Sol–gel processed ZnO films are widely used as electron transport layers (ETLs) in organic solar cells (OSCs). However, defects caused by COOH, OH, and vacancies of oxygen in ZnO ETLs are harmful for electron extraction and transport processes in OSCs. Here, a simple and effective strategy is reported to passivate free OH via hydrogen bond of HO…NH2. A small molecule of biuret is introduced into ZnO precursor as an additive to form ZnO films. The hydrogen bond of HO…NH2 is confirmed by XPS and FT-IR in this study, which passivates traps originated from free OH. The passivated ZnO ETLs exhibit better morphology and higher electron mobility than pristine ZnO ETLs. In OSCs with fullerene and non-fullerene light absorbers, the cells with biuret-doped ZnO ETLs obtain improved power conversion efficiency (PCE), which prove the generality of biuret doped ZnO ETLs. Eventually, a maximal PCE of 18.19 % is obtained when PM6:L8-BO is selected as light absorber. Furthermore, the contributions of biuret are discussed in this work.

Efficient recovery of iron from anaerobic roasted cyanide tailings using advanced oxidation technology

Persulfate-mediated advanced oxidation process (AOP) has been used to oxidize iron and sulfur bearing minerals, but the iron leaching process and the activation of persulfate by minerals themselves has been neglected. In this study, AOP was used to leach iron from cyanide tailings, roasted in a nitrogen atmosphere. The oxidation behavior of pyrrhotite and the activation mechanism of persulfate were proposed through process optimization, product analysis, reactive species and degradation area. The iron leaching efficiency from roasted cyanide tailings was 97.1%, with a mass loss ratio of 32.5%. The gold grade in leach residues increased from 1.19 g/t to 2.07 g/t under the leaching conditions: sodium persulfate concentration of 0.3 mol/L, leaching temperature of 60 °C, slurry concentration of 30 g/L, and stirring speed of 300 rpm. The pyrrhotite in roasted cyanide tailings was oxidized by persulfate and the free radicals produced by its activation. Oxidation products were Fe3+, SO42−, and elemental sulfur. The oxidation of pyrrhotite was dominated by the indirect oxidation by the free radicals OH• and SO4−•, and their contributions to the iron leaching efficiency were 66.6% and 24.2%, respectively. The reason for the thermally enhanced iron leaching effect was the activation of persulfate to produce a certain amount of OH•. The Fe2+ produced by the oxidation of pyrrhotite activated persulfate to produce SO4−• and OH•. Besides, S(II) in pyrrhotite mediated the circulation of iron ions, thereby continuously producing Fe2+ to activate persulfate.

Mucoactive therapy in the treatment of sinusitis in patients with post-Covid syndrome

Rhinosinusitis, as in the pre-ovoid era, are still the most common diseases in the practice of an otorhinolaryngologist. According to the results of the analysis of medical documentation conducted at the clinic of the St. Petersburg Scientific Research Institute of Ear, Throat, Nose and Speech, more and more patients associate the diseases of the nasopharyngeal space that have appeared in them and the increase in the number of exacerbations of existing chronic diseases of this area with a coronavirus infection. In this regard, we decided to consider approaches to the treatment of rhinosinusitis by summarizing the available data and considering individual clinical cases of patients with sinusitis and COVID-19. Antibiotic resistance associated with uncontrolled administration of antibacterial drugs when infected with SARS-CoV-2 has also become one of the frequent problems at present. Therefore, our article considers the most relevant method in this case, based on the use of phytotherapy. According to the literature, the most effective phytopreparations are preparations containing standardized myrtol, which reduces the viscosity of the mucus of the paranasal sinuses and nasal cavity, increases the frequency of beating of the cilia of the ciliated epithelium, thereby contributing to an increase in the speed of mucociliary transport. Standardized myrtol also has an anti-inflammatory effect by reducing the concentration of leukotrienes and prostaglandin, neutralizing free OH radicals, inhibiting oxidation processes myrtol reduces toxic effects on the nasal mucosa and paranasal sinuses, and also acts on pathogenic flora as a bacteriostatic drug. Clinical recommendations of the Ministry of Health of the Russian Federation from 2021 according to the treatment of acute sinusitis and the European recommendations of the European Position Paper on Rhinosinusitis and Nasal polyps (EPOS 2020), based on the data of controlled studies presented in them, the use of phytopreparations in the treatment of acute and chronic sinusitis is confirmed both in combination with antibacterial therapy and without antibacterial drugs in combination with irrigation therapy and the use of topical decongestants.