The paper presents the results of pH, redox, and conductometric studies on the acid-base interaction during sulfur dioxide chemisorption by aqueous solutions containing 0.1 mol/L monoethanolammonium (MEA·1/3CA) and polyethylenepolyammonium (PEPA·1/3CA) citrates, as well as buffer solutions of monoethanolamine–monoethanolammonium citrate (MEA·1/6CA) and polyethylenepolyamine–polyethylenepolyammonium citrate (PEPA·1/6CA), in comparison with sodium citrate. The composition of the compounds formed during SO2 absorption by Na3Cit, MEA·1/3CA, PEPA·1/3CA, MEA·1/6CA, and PEPA·1/6CA solutions at 273–313 K was determined.For the same amount of absorbed sulfur dioxide, an increase in specific electrical conductivity (æ) with rising temperature was observed in SO2–Na3Cit–H2O and SO2–MEA×1/3CA–H2O solutions within the 273–313 K range. However, in the SO2–MEA×1/3CA–H2O, SO2–PEPA×1/3CA–H2O, SO2–MEA×1/6CA–H2O, and SO2–PEPA×1/6CA–H2O systems, a decrease in Δæ was noted upon heating to 303 K, which is attributed to their ion-molecular composition. Based on developed mathematical models, the ion-molecular component composition of SO2–MEA×1/3CA–H2O and SO2–MEA×1/6CA–H2O solutions was determined at 283–313 K. The concentration and thermodynamic constants for the formation of ionic associates were calculated:(NH3CH2CH2OH)2SO3, {H3CH2CH2OH}{HOC3H4(COOH)2(COO-)} (Ia), {H3CH2CH2OH}2{HOC3H4(COOH)(COO-)2} (IIa), {H3CH2CH2OH}2{HOC3H4(COOH)2(COO-)} (IIb), {H3CH2CH2OH}3{HOC3H4(COO-)3} (IIIa), as well as ion-molecular associates:{H3CH2CH2OH}{HOC3H4(COOH)3} (Ib), {NH2CH2CH2OH}3{H3CH2CH2OH}3{HOC3H4(COO-)3} (IVa), {NH2CH2CH2OH}2{H3CH2CH2OH}4{HOC3H4(COO-)3} (IVb). In SO2–MEA×1/3CA–H2O solutions, as the temperature increases, bond rearrangement occurs in ionic associates IIa and Ib, as indicated by the absence of a clear temperature dependence ofp, along with the strengthening of IIa and Ib. Conversely, in SO2–MEA×1/6CA–H2O solutions, increasing temperature leads to the weakening of the bonds in compounds Ia, IIIa, IVa, and IVb, while in compound Ib, the bonds strengthen.

Interaction in the system "sulfur dioxide–diethylenetriamine (or bis-(hexamethylene)triamine)–water–air oxygen" results in a mixture of double salts (diethylenetriammonium bis(sulfito)-dithionate (Ia) and bis(sulfito)-sulfate trihydrate diethylenetriammonium (Ib)) or bis(hexamethylene)triammonium sulfate (II). The obtained ammonium salts of sulfur-containing oxyanions Ia, Ib, and II were characterized by the methods of elemental analysis, X-ray structural analysis, X-ray powder diffraction, IR spectroscopy, and mass spectrometry. Compound Ia crystallizes in monoclinic syngony (space group С2/с, a=28.1583(5) Å, b=6.84450(10) Å, c=10.8351(2) Å, =93.776(2)0, V=2083.71(6) Å3, Z=4). Compound Ib crystallizes in rhombic syngony (space group Pbcn, a=18.9777(13) Å, b=10.3131(8) Å, c=11.5414(10) Å, V=2258.9(3) Å3, Z=4). Compound II crystallizes in triclinic syngony (space group P-1, a=11.347(3) Å, b=11.700(5) Å, c=18.913(4) Å, =95.22(3)0, =92,52(2)0, =118,27(4)0, V=2191,36 Å3, Z=2). The IR spectrum of the mixture of salts Ia and Ib shows the valence vibrations of (SO) of sulfite anion (1 and 3), represented by bands at 955, 931, 907, 1026, and 1006 cm–1. Two bands at 566 and 493 cm–1 are the result of the splitting of a doubly degenerate out-of-plane deformation vibration of the 4 (E) of dithionate anion. The bands at 1127 and 1078 cm–1 correspond to the oscillations of as and s of sulfate anion (SO42–). A decrease in the symmetry of the SO42– anion as a result of salt formation is accompanied by the appearance of the band 1 (A1) at 980 cm–1 in its spectrum.

The reaction products formed in the SO2 – ROH – (HOCH2)3CNH2 (where R – CH3, C2H5, n-C3H7, i-C3H7, n-C4H9 and n-C5H11) systems were isolated and identified as: binary salt – ammonium O-methylsulfite [(HOCH2)3CNH3]+ [CH3OSO2]− (1); 1/1 charge transfer complex between diethyl sulfite (2) and tris(hydroxymethyl)aminomethane by S-N binding; polymorhps of zwitterionic internal salt – O-sulfite tris(hydroxymethyl)methylammonium (at R – n-C4H9 and n-C5H11); and its solvates with n-propanol 1/1 (3) and isopropanol 2/1. The structures of all synthesized products were confirmed by FT-IR, Raman, 1H NMR and 13C NMR spectrometry, and the structure of 1 and 3 was characterized by crystal X-ray diffraction studies as well.

pH and conductometric study of aqueous (0.1 ÷ 9.0)⋅10-3 mol/l solutions of sodium (Na3Cit), monoethanolammonium (H3Cit⋅3MEA) and polyethylenepolyammonium (kH3Cit⋅3PEPA) citrates was carried out. Features of the electrochemical behavior of monoethanolamine and polyethylenepolamine ammonium citrates aqueous solutions were revealed in comparison with Na3Cit. As the temperature increases from 293 to 303 K, the pH values and Na3Cit solutions molar electrical conductivity increase. Due to hydrolytic processes, when diluting H3Cit⋅3MEA solutions, a change in pH is observed from slightly acidic to slightly alkaline, in contrast to Na3Cit. An increase in temperature (in the region of 293–308 K) leads to an increase in the medium acidity, in contrast to sodium citrate solutions, which is accompanied by an atypical decrease in molar electrical conductivity at the same H3Cit⋅3MEA content. It has been shown that an increase in temperature in the range of 293-308 K leads to a decrease in H3Cit⋅3MEA aqueous solutions pH, in contrast to Na3Cit and kH3Cit⋅3PEPA solutions, which is accompanied by an atypical decrease in molar electrical conductivity at the same H3Cit⋅3MEA content. The component composition of Na3Cit, H3Cit⋅3MEA and kH3Cit⋅3PEPA aqueous solutions was calculated. The probability of the existence of negatively charged ion-molecular complexes in H3Cit⋅3MEA and kH3Cit⋅3PEPA aqueous solutions is shown. The concentration and temperature dependence of citrate ions hydrolysis constant was obtained. The concentration and temperature dependence of these complexes was assessed. The atypical negative effect of heating on H3Cit⋅3MEA aqueous solutions molar electrical conductivity is associated with a change in the radius of the ion-molecular complex and its stability. The value of the limiting molar electrical conductivity of sodium, monoethanolammonium and polyethylenepolyammonium citrates aqueous solutions in the range of 293–313 K was estimated. Correlations were revealed between the values of the limiting electrical conductivity and ion-molecular complexes formation constants in H3Cit⋅PEPA aqueous solutions. The values of energy, enthalpy and entropy of activation of molar electrical conductivities of aqueous solutions were calculated. For the solutions studied, compensation effects were noted in the activation parameters of molar electrical conductivity.

Встановлення особливостей кислотно-основної та електрохімічної поведінки в системах H3Cit – Am – H2O (H3Cit – лимонна кислота; Am – моноетаноламін (MEA) і поліетиленполіамін (PEPA)) та їх структурних характеристик є актуальним завданням. Здійснено рН- та кондуктометричне дослідження протеолітичних рівноваг в системах HOC3H4(COOH)3 – NH2CH2CH2OH – H2O та HOC3H4(COOH)3 – NH2(CH2CH2NH)kH– H2O із сумарним вмістом цитратних форм 1.0 М в області температур 293 ¸ 313 К. Оцінено міжмолекулярні взаємодії у вказаних системах у порівнянні із розчинами цитрат натрію (Na3Cit) – лимонна кислота – вода за 298 К. Порядок додавання компонентів суттєво впливає на значення pH отриманих розчинів, на відміну від питомої електропровідності та густини. За однакового сумарного вмісту цитратів за значеннями питомої електропровідності досліджені системи можна розташувати в наступний ряд: Na3Cit – H3Cit – H2O > MEA – H3Cit – H2O > PEPA – H3Cit – H2O. Це зумовлено рухливістю катіонів та додатковим утворенням катіон-молекулярних комплексів і йонних асоціатів за рахунок H-зв’язування в системах із MEA та PEPA. За даними денситометрії введення у водний розчин H3Cit MEA та PEPA, на відміну від Na3Cit, призводить до структурування системи. Положення зламів на денситометричних кривих відповідають зламам на кондуктометричних; значення питомої електропровідності досліджених розчинів корелюють з їх густиною. Розраховані іон-молекулярний склад та йонна сила досліджених розчинів. Проведено оцінку концентраційних та термодинамічних констант утворення катіон-молекулярних комплексів і йонних асоціатів.

Acid -base and electrochemical behavior in the systems H-3 Cit - Am - H2O (H-3 Cit - citric acid; Am - monoethanolamine and polyethylene polyamine) and their structural characteristics features establishment is an urgent task. The pH and conductometric study of protolytic equilibria in the systems HOC3 H-4(COOH)(3) - NH2 CH2CH2OH - H2O and HOC3 H-4( COOH)(3) - NH2 (CH 2 CH 2 NH) k H - H2O was carried out with the total content of citrate forms (citric acid, dihydrogen citrate, hydrogen citrate and citrate anions, cation -molecular complexes and ionic associates) 1.0 M in the temperature range 293-313 K. Intermolecular interactions in these systems were estimated in comparison with sodium citrate - citric acid - water solutions at 298 K. The order of components adding affects resulting solutions pH values in contrast to the specific electrical conductivity and density. With the same total citrates content according to the specific electrical conductivity values the studied systems can be arranged in such series: HOC3H4(COONa)(3) - HOC3H4(COOH)(3) - H2O > NH2 CH 2 CH2OH - HOC3H4(COOH)(3) - H2O> NH2 (CH2CH2NH) k H - HOC3H4(COOH)(3) -H2O. This is because of the mobility of cations and the additional formation of cation -molecular complexes and ionic associates due to H -bonding in the monoethanolamine and polyethylene polyamine systems. According to densitometry, the organic amine (monoethanolamine or polyethylene polyamine) introduction into an citric acid aqueous solution in contrast to sodium citrate results the structuring of the system. The breaks positions on the densitometric curves correspond to the breaks on the conductometric curves; the studied solutions specific electrical conductivity values correlate with their density. The investigated solutions cation -molecular compositions and ionic strengths were calculated. The cation -molecular complexes and ionic associates concentration and thermodynamic formation constants estimation was carried out. The obtained results can be useful to evaluate of the solutions studied in this work buffer properties as well as for developing of chemisorbents based on them.

Much research attention has been paid to amino acids as an alternative to amino alcohols for capture of sulfur dioxide. Taurine (Tau) occupies a special place among amino acids. This study was stimulated by the limited literature data on the nature of the interaction of SO2 with Tau salts aqueous solutions, the composition and relative stability of the corresponding reaction products. Chrono-pH-, chrono-redox- and chrono-conductometric studies of SO2 chemisorption with potassium taurate (TauK) and monoethanolammonium (TauMEA) aqueous 0.1 M solutions were carried out in the temperature range 293–313 K to study these processes. The maxima on the differential pH-metric titration curves positions coincide with the positions of the jumps on the integral and maxima on the redox-metric titration differential curves, as well as with breaks on the conductometric curves position. Δk negative values indicate the formation of weakly dissociated particles or less mobile ions in the solutions under study that is confirmed by the data of mathematical calculations. Using a mathematical model that takes into account the law of mass action, material balance and electrical neutrality principle, SO2 – TauK – H2O solutions ion-molecular composition and ionic strength were calculated. With an increase in the chemisotption SO2 amount, the taurate anions concentration decreases due to the hydrolytic transformation into zwitter ions +NH3CH2CH2SO2O - and the sequential transformation of hydrotaurate-sulfite (4:1 and 2:1; I and II), taurate-sulfite (2:1; III), hydrotaurate-hydrosulfite (2:1; IV) and taurate-hydrosulfite (1:1; V) associates. The concentration and thermodynamic constants for the formation ionic associates I–V were calculated. TauK input into impregnated fibrous chemisorbents (IFCS) composition obtained by impregnating viscose fibers with monoethanolamine aqueous 0.25 M solutions (IFCS-0.25MEA) leads to a synergistic increase in quantity of adsorbed SO2. IFCS-0.25MEA-TauK are long-acting sulfur dioxide chemisorbents, and TauK itself serves as a promoter-modifier towards IFCS-0.25MEA preventing the MEA removal from IFCS surface by the GPS flow due to the ionic associates formation and promoting deeper HOCH2CH2NH2 «response».

The study of data on acid-base properties of model systems SO2 – KOH – TrOOO – H2O and SO2 – Am – TrOOO – H2O (TrOOO – tropeoline OOO; Am – diethanolamine (DEA), triethanolamine (TEA), N‑methylmonoethanolamine (MMEA) and morpholine (Mf) at 293 K using pH-, spectrophotometry and colorimetry methods are presented. There is a pronounced isosbestic point at 415 nm in the electronic absorption spectra of the systems SO2– Am –TrOOO– H2O (Am = MMEA, MEA and TEA; pH ≤ 7.5; T = 293 K), which indicates the presence of a dynamic equilibrium between ion-molecular forms. According to the width of the absorption spectra, the bases in the region of 2.0 ≤ pH ≤ 8.0 can be arranged in the following row: MEA > Mf > KOH > DEA > TEA > MMEA. The bases can be arranged in the following rows for the effect on optical density at 490 nm: KOH > Mf ≥ MEA > DEA ≥ TEA (at 5.5 ≤ pH < 9.0); KOH = MEA = Mf > DEA = TEA (at pH < 6.0). According to the values of optical density at 360 nm in the region of 2.0 ≤ pH < 8.5, the bases can be arranged in the following row: Mf > KOH ≥ MEA ≥ DEA > MMEA > TEA. The total color difference (ΔE76) and specific color difference (SCD) values were calculated by colorimetric method as a function of pH. The acid–base dissociation constants in the SO2 – Am (KOH) – TrOOO – H2O systems significantly depend on the structure and physicochemical properties of the organic base and differ significantly from those in the HCl (HClO4, H2SO4) – MEA – TrOOO – H2O systems. The interrelation of colorimetric functions was established (total color difference and specific color difference) of SO2 – Am – TrOOO – H2O systems with molar refraction Am, empirical function pKa – lgPow, which combines the basicity and hydrophilicity of Am, formation constants of ammonium sulfites and hydrosulfites, pH- (dpH/dpQSO2), redox- (dЕ/dpQSO2) and conductometric (Dk) titration curves of Am aqueous solutions with gaseous sulfur dioxide.

The review is devoted to the use of impregnated activated carbon materials as chemisorbents of sulfur (IV) oxide. General methods for obtaining ordinary activated carbon, preparation of raw materials, their chemical activation with alkalis and acids followed by heat treatment (carbonization) in an inert environment or in the presence of a gaseous oxidizer, the role of acid-base and redox catalysts in this process are considered. The influence of the chemical composition of the activated carbon surface, the presence of functional groups, and their acid-base properties, as well as the products of surface reactions on the peculiarities of sulfur (IV) oxide adsorption is analyzed from the point of view of SO2 removal efficiency and the possibility of SO2 regeneration. An important role in these processes is played by the pore size, the possibility of co-adsorption of water, and the presence of an oxidant. The nature of adsorbent-adsorbate interactions on the surface of activated carbon, their ener­gy, in particular, the contribution of so-called "physical" adsorption, van der Waals forces, hydrogen bonding, and the influence of surface functional groups are discussed. The activation of carbon raw materials with nitrogen-containing compounds leads to the N-doping of the surface, which increases the efficiency of SO2 adsorption, facilitating not only van der Waals and electrostatic interactions, but also S←N binding. The influence of oxygen and oxygen-containing functional groups on SO2 adsorption is also discussed. To obtain impregnated activated carbon for SO2 absorption, the original activated carbon of the required quality is impregnated with solutions of inorganic and organic compounds that remain on the inner surface of the activated carbon after drying. Impregnation blocks partly the porosity of activated carbon, but makes it more capable of chemical adsorption. Chemisorption, in which certain chemical bonds are formed between the surface of the activated carbon and the compound being adsorbed, is more selective than physical adsorption, where the size of molecules is critical for an effective capture process. It can be noted that unlike inorganic alkalis, which spoil the porous structure of activated carbon, treatment with a solution of ammonia or organic N-containing bases promotes SO2 absorption. A special place in gas purification is occupied by activated carbon impregnated with ionic liquids, non-aqueous solvents being used for impregnation. A separate issue of the chemisorption of sulfur (IV) oxide by samples of impregnated activated carbon based on d-metals will be discussed in detail below.

In the current study stability of hexamethylenetetramine (HMTA) aqueous solutions without acid additives (HCl, H2SO4, citrate-phosphate buffer systems, etc.) in the range of temperatures 1.0 divided by 20.0 degrees C and concentrations of HMTA 0.10 divided by 1.0 M (pH(0) = 7.05 divided by 8.25) was investigated by the spectrophotometric and potentiometric (pH and redox) methods. The obtained data indicate the complexity of the mechanism of hydrolytic transformations and acid-base interactions in the studied HMTA solutions. It was noted that the mechanism of disproportionation of HMTA in water significantly depends on temperature and its concentration. The contents of ammonium ions and formaldehyde as the final products of HMTA hydrolysis was determinated. The molar concentration of ammonium ions is no more than 5.0 % of the total content of HMTA and is several times higher than the formaldehyde concentration. It is shown that the dynamics of ammonium ions and formaldehyde accumulation does not correlate with the potentiometric curves. It was established that hydrolytic stability of HMTA aqueous solutions increases with it concentration. Recommendations for the preparation of buffer solutions based on HMTA are formulated. It is noted that it is desirable to prepare aqueous HMTA solutions of high concentration (>= 0.50 M) and store them at room temperature. An algebraic equation that describes the ratio of volumes of solutions of 1.00 M (2.50 M) HMTA and 0.10 M HCl, which are required for the preparation of buffer solutions with a certain pH in the range of 4.30 divided by 7.40 (5.00 divided by 7.50) was obtained. Mathematical model that describes the concentration dependence of the HMTA - HCl - H2O buffer solutions capacity and the influence of dilution on the change in pH has been proposed. It is noted that the buffer capacity of the studied buffer system depends significantly on the concentration and ratio of the components in the solution.

The paper presents the research results on the colorimetric behavior of impregnated fibrous chemisorbents (IFCS-I) of acid gases with visual identification of the dynamic absorption capacity “response” moment during the absorption of sulfur dioxide. Chemisorbents were obtained by impregnation of fibrous carriers by N-containing organic bases aqueous solutions with adding acid-base indicators (Ind). IFCS-I based on hexamethylenetetramine (IFCS-HMTA-I) and polyethylenepolyamine (IFCS-PEPA-I), as well as IFCS-MEA-EDTA-I based on monoethanolamine (MEA) and the disodium salt of ethylenediaminetetraacetic acid (EDTA) were used. The change specificity of colorimetric functions of indicator impregnated fibrous chemisorbents during their absorption of SO2 is revealed. IFCS-I original samples color significantly depends not only on the structure of Ind, but also the nature of amines (MEA, HMTA and PEPA), which are part of them. The color of the “response” samples of IFCS-MEA-EDTA-I, IFCS-PEPA-I and IFCS-HMTA-I, differ from the same properties of Bronsted acids aqueous solutions. The color change of azo-indicators occurs due to redox reactions with sulfite compounds. PEPA molecules and their ammonium cations in the composition of IFCS-I stabilize azo-indicators to these redox transformations.

The protolytic equilibria in the system citric acid (H3Cit)–sodium citrate (Na3Cit)–water at a total content of citrates forms (citric acid, dihydrocitrate (H2Cit-), hydrocitrate (HCit2-) and citrate (Cit3-) anions) 1.0 mol/l have been studied by pH- and conductometric methods in the temperature range 293 ÷ 313 K. The first concentration ranges at which pH – lg(νH3Cit/νNa3Cit) and κ – CNa+/Ccit functions are linear correspond to the H3Cit/H2Cit- buffer system; the second ones – to H3Cit/H2Cit- and H2Cit-/HCit2-; the third ones to – HCit2-/Cit3- buffer system. The investigated solutions ion-molecular composition and ionic strength (m, mol/l) have been calculated using the mathematical model taking into account the law of mass action, material balance for citrates and electrical neutrality principle. The ionic strength concentration dependences have a complex character due to the ion-molecular composition multicomponent nature for the studied solutions. The ionic strength values are directly proportional to the ratio [Na+]/CCit in the concentration intervals 0 ≤ [Na+]/CCit ≤ 1.0 and 2.0 ≤ [Na+]/CCit ≤ 3.0. In the concentration range 1.0 ≤ [Na+]/CCit ≤ 2.0, the values of m = 1.15 ± 0.27 mol/l) weakly depend on the [Na+]/CCit ratio and practically do not depend on temperature. Citric acid concentration and thermodynamic constants for the first, second, and third dissociation stages have been determined. The obtained data on the acid-base and electrochemical characteristics of the solutions HOC3H4(COOH)3 – HOC3H4(COONa)3 – H2O(СCit = 1.0 mol/l; СNa+ = 0 ÷ 1.0 mol/l) can be used in chemical analysis, microbiological and biochemical studies, and the acidity data of the solutions studied can simulate chemisorption of acidic (SO2) and/or basic (NH3) gases.

Досліджено стабільність водних розчинів гексаметилентетраміну (HMTA) без кислотних добавок (HCl, H2SO4, цитратно-фосфатні буферні системи тощо) в області температур 1.0 ÷ 20.0 °С та концентрацій HMTA 0.10 ÷ 1.0 М (pH0 = 7.05 ÷ 8.25) методами спектрофотометрії, прямої рН- та редоксметрії. Оцінено вміст іонів амонію та формальдегіду – кінцевих продуктів гідролізу HMTA. Молярна концентрація іонів амонію складає не більше 5.0 % від загального вмісту HMTA та у кілька разів вища за концентрацію формальдегіду. Показано, що динаміка накопичення іонів амонію та формальдегіду не корелює із ходом потенціометричних кривих. Встановлено, що зі збільшенням концентрації водних розчинів HMTA (0.50 та 1.00 М) підвищується їх гідролітична стійкість. Отримано алгебраїчне рівняння, що описує співвідношення об’ємів розчинів 1.00 М (2.50 М) HMTA та 0.10 М HCl, які необхідні для приготування буферних розчинів із певним значенням pH в області 4.30 ÷ 7.40 (5.00 ÷ 7.50). Запропоновано математичну модель, яка в першому наближенні описує концентраційну залежність буферної ємності розчинів HMTA – HCl – H2O. Показано, що розведення в тисячу разів розчинів, які приготовлені на основі 1.00 М HMTA та 0.10 М HCl (рН0 5.45 та 6.35), а також 2.50 М HMTA та 0.10 М HCl (рН0 5.90) практично не призводить до помітних змін значень рН.

The influence of relative humidity (RH) of the gas-air environment on the ammonia chemisorption by impregnated fibrous chemisorbent (IFCS) is studied. IFCS was obtained by impregnating nonwoven needle-punched material from polyester fibers with an aqueous solution of citric acid (40 w%) with modifiers (glycerin, sodium chloride and ethanol) to uniformly distribute the chemisorbent on the surface of the fibers and increase adhesion to the composition of the impregnating solution. It is shown that for all values of relative humidity the curves of ammonia breakthrough through a fixed layer of IFCS спр(tпр) in the coordinates ln(c0/спр -1), tпр are reliably R2 > 0.95 approximated by straight lines and the Wheeler-Jonas theoretical model can be used for the quantitative description of the ammonia-IFCS system. By comparing the experimental and theoretical curves спр(tпр) in the coordinates ln(c0/спр -1), tпр the unknown model parameters were determined: the chemisorption rate constant and the sorption capacity of the IFCS unit mass and their dependence on the relative humidity of the gas-air environment (GAE). It has been established that the IFCS sorption capacity increases linearly with increasing, and the chemisorption rate constant of the ammonia-IFCS system does not depend on the GAE relative humidity and is equal to . The influence of the GAE relative humidity and the thickness of the IFCS layer on the ammonia breakthrough time is experimentally investigated and the adequacy of using the Wheeler-Jonas model for predicting the service life of IFCS for real use conditions is substantiated.

Background. The spread of a new strain of SARS-CoV-2 and the pandemic that caused it has led to huge changes around the world. So, it reminded us again about the importance of developing measures for the prevention of infections that transmitted by air droplets. Aim: investigation of the antimicrobial activity of aminomethanesulfonic acid (AMSA) and its derivatives (N-(2-hydroxyethyl)-(HEAMSA), N-benzyl-(BnAMSA) and N-(tert-butyl)-(t-BuAMSA)) which impregnated on filtering fibrous material and can be used for the manufacture of anti-aerosol elements of individual respiratory protection against strains of Staphylococcus aureus with different level of antibiotics resistance. Materials and methods. The standard method of Kirby and Bauer disks is used for the investigation of the specific activity of antimicrobial drugs. The 24-hour cultures of microorganisms that contained (1.2+0.2)x109 CFU/ml were diluted according to the turbidity standard. The results were detected after 18-20 hours of incubation at 37°C. The 0.5 cm diameter filter fibrous discs contained the following compounds: AMSA, HEAMSA, BzAMSA, t-BuAMSA and streptocide (sulfanilamide) as a reference with active compound content (Q) at a final concentration of 0.047 and 0.236 mmol/g. Results. All test samples with aminomethanesulfonic acids at a final concentration of 0.236 mmol/g that were applied to the filter fibrous material had a higher level of inhibition of the growth of the microorganisms than the prototype using streptocide (sulfanilamide) e against the strains of Staphylococcus aureus 2781 and Staphylococcus aureus Kunda. Conclusions. Samples based on HEAMSA showed the greatest antimicrobial activity against the studied strains of Staphylococcus aureus from all research samples of filter fibrous material with YAMSA. They were characterized by the maximum hydrophilicity and the minimum value of the empirical pKa function lgPow. AMSA and HEAMSA were characterized by the smallest particle sizes on the surface of lavsan fiber according to electron microscopy analysis. This provides the largest boundary of contact between the phases of these biocides in the composition of the filtering fibrous material with bio aerosols during respiratory air purification.

This paper summarizes the data on the development of import-substituting impregnated This paper summarizes the data on the development of import-substituting impregnated fibrous chemisorbents (IFCS) intended for equipping gas cleaning equipment and personal respiratory protection equipment against gaseous toxicants of various chemical nature. To obtain IFCS of the basic gases (ammonia, organic amines), aqueous solutions of polybasic acids (citric, tartaric and hydroxyethylenediphosphonic) are used as impregnating reagents. IFCS absorb toxicants due to neutralization reactions. The absorption of ammonia and amines of IFCS obtained by impregnation of fibrous carriers (FC) with aqueous solutions of 3d-metals (Ni2+, Co2+ and Cu2+) salts occurs due to complex formation reactions. To obtain IFCS of acidic gases, aqueous solutions of sodium carbonate and urotropine (HMTA) containing structuring additives were used. Impregnating aqueous solutions based on monoethanolamine (MEA) and polyethylenepolyamine (PEPA) have also been developed using their non-volatile derivatives with a higher molar mass. A significant improvement of the IFCS protective characteristics was achieved by introducing of various modifying additives – promoters into the composition of these solutions. Single-layer IFCS -ampholytes (IFCS-A) for respiratory purposes have been developed, which depending on the circumstances are able to absorb both acidic and basic gases (vapours), for example SO2 and NH3. Impregnation solutions include complex compounds of 3d-metals (Ni2+, Co2+ and Cu2+) with MEA, ethylenediamine, HMTA and PEPA at various molar ratios of components or buffer mixtures based on polybasic acids and organic bases (MEA and PEPA) of medium strength salts. Chemisorbents for acidic and/or basic gases (IFCS-I, IFCS-AI) have been developed, the moment of “response” of the dynamic absorption capacity of which can be visually determined by the change in color of the gas mask elements during the “breakthrough” of the sorbate, obtained by impregnating of FC with solutions containing acid-base indicators.

Одним з найперспективніших шляхів розробки потенційних лікарських препаратів залишається спрямований синтез нових сполук, у тому числі серед похідних амінометансульфонової кислоти (АMSA). Мета дослідження – оцінка потенційної біологічної та фармакологічної активності низки похідних АMSA за допомогою комп’ютерної системи PASS. Розрахунок потенційної біологічної активності похідних AMSA проводили за допомогою PASS (Prediction of Activity Spectra for Substances). Показник (імовірності) Ра від 0,7 до 1,0 свідчить про високу ймовірність активності. Були досліджені: N-(2-гідроксиетил)-AMSA (HEAMSA), N-(пропіл)AMSA (PrAMSA), N-(бутил)-AMSA (BuAMSA), N-(трет-бутил)-AMSA (tBuAMSA), N-(гептил)-AMSA (HpAMSA), 4-(N-феніламінометил)феніл-AMSA (PhAMPhAMSA), N-(бензил)-AMSA (BzAMSA). За результатами дослідження в чотирьох сполук (HEAMSA > BzAMSA > PrAMSA > tBuAMSA; Pa = 0,702…0,822) передбачається здатність пригнічувати глікозилфосфотидилінозитол фосфоліпазу D, що вказує на можливість пригнічувати ріст пухлинних і стовбурових клітин. Сполуки HEAMSA, PrAMSA, BuAMSA, tBuAMSA, HpAMSA виявили здатність пригнічувати екзорибонуклеазу ІІ, що зумовлює наявність противірусної активності. Практично всі досліджувані сполуки ймовірно пригнічують активність ферментів ендоглюкозилцерамідази та цукор-фосфатази, що може зумовлювати гіпоглікемічну активність. При цьому за останньою активністю Ра = 0,732…0,815, а за силою дії сполуки розташувались наступним чином: HpAMSA > BuAMSA > PrAMSA > HEAMSA > tBuAMSA > BzAMSA. У всіх досліджених похідних АМSA, крім BzAMSA, прогнозується антигіпоксична активність, за силою якою сполуки розташувались наступним чином: BuAMSA > HpAMSA > HEAMSA > PrAMSA > tBuAMSA > PhAMPhAMSA (Pa = 0,705…0,814). Сполуки HEAMSA і PrAMSA можуть викликати анксіолітичну дію, сполука tBuAMSA – аналгетичну дію, PhAMPhAMSA – антипіретичну дію, сполуки BuAMSA, HpAMSA можуть пригнічувати про-опіомеланокортин (РОМС) конвертуючий фермент. РОМС є прогормоном, з якого утворюються адренокортикотропний і меланоцит-стимулюючий гормони, а також бета-ліпотропін і бета-ендорфін. Тому пригнічення процесу лізису РОМС може впливати на ендокринну й антиноцицептивну системи. Таким чином, наведені дані свідчать про перспективність доклінічного дослідження нових похідних амінометансульфонової кислоти.

Recently, the practice of analytical chemistry has included the method of chemical chromaticity, based on the measurement of the integral characteristics of the color reflected from the surface of the analyte and which makes it possible to distinguish between spectrally close substances. With the spread scanners and computer programs for color image processing, a fast and objective method for assessing the color characteristics of colored samples has appeared, opening up the prospect of using chemical chromaticity in the chemical analysis of various objects in the absence of special spectrophotometric equipment or with minimal use of it. Thus, the process of chemical chromaticity analysis is divided into two parts: obtaining a high-quality digital image of the analyzed object and processing the resulting file in a graphics editor. The article describes in detail the methodological issues of scanning solutions, powders, surfaces of dosage forms using an office scanner and processing the resulting digital images in a graphics editor. On the example of model samples, standard solutions of salts FeCl3⋅6H2O, CoCl2⋅6H2O, CuSO4⋅5H2O, it is shown that in the range of 6–60 g/l their concentrations can be determined with sufficient accuracy as with using its absorption spectra (registered on a Lambda 9 PerkinElmer spectrophotometer) or spectra of diffuse reflection (on the same instrument using a scanning sphere B013–9941), and when using an desktop scanner HP scanjet 2200c with HP PrecisionScan LTX 1.2 software, followed by digital processing of the scan in Photoshop CS3. Acquisition and analysis of digital images of analytes can be considered as an inexpensive replacement for spectrophotometry in a certain interval of concentrations, comparable with it in terms of accuracy and reliability of determinations. The introduction of this technique into the educational process makes it possible to increase the efficiency of teaching students when mastering the skills of converting color characteristics into optical density values and to better understand the principles of the science of color and light absorption. The method can be made mobile for analysis of results in remote areas using a portable scanner powered by battery.

The limits of the pH buffering action (pHbuff) of YNHCH2SO3H – NH2CH2CH2OH –H2O (Y = H, CH3, HOCH2CH2, t-С4H9 and C6H5CH2) were determined and their buffer capacity (p) for monoethanolamine (MEA) was estimated in the temperature range 293–313 K. For systems with aminomethanesulfonic acid (AMSA), its N‑methyl, N‑hydroxyethyl (HEAMSA) and N‑benzyl (BzAMSA) derivatives, an increase in temperature leads to a decrease in the pH values of the lower limit of the buffering action of their solutions with monoethanolamine; in the case of N‑tert-butylaminomethanesulfonic acid (t-BuAMSA) – to an increase in the specified characteristic. An increase in temperature for systems with the most hydrophobic t-BuAMSA and BzAMSA (in comparison with other studied aminomethanesulfonic acids) leads to a decrease in the pH values of the upper limit of the buffer action. A decrease in the YNHCH2SO3H and NH2CH2CH2OH concentration leads to a shift in the boundaries of the pH of the buffering action to a more acidic region. The nature of the influence of the empirical function, combining their acid-base properties and lipophilicity (рKа + lgPow), on the concentration dependence of the buffer capacity according to MEA was revealed. It is shown that the buffering effect of the studied systems is due to the presence, in addition to the systems N‑alkylammoniummethanesulfonate – N‑alkylaminomethanesulfonate and 2-hydroxyethylammonium – monoethanolamine, ionic associates (pairs and triples). The position of the extrema on the graphical π=f(CMEA)/QYAMSA) dependencies for systems with hydrophilic AMSA and HEAMSA coincides with the position of the first minima on the differential titration curves dpH/dV = f(CMEA)/QYAMSA). Substitution of MEA to potassium aminomethanesulfonate leads to a shift in the pH buffering action to a more acidic region and increases the buffer capacity of the resulting systems.