Methanol-water Mixtures Research Articles

Spectroscopic, anti-cancer, anti-bacterial and theoretical studies of new bivalent Schiff base complexes derived from 4-bromo-2,6-dichloroaniline

In this paper, four new mono-nuclear Ni(II), Pd(II), Pt(II) and Zn(II) complexes were prepared by using a bi-dentate Schiff base ligand, (E)-2-(((4-bromo-2,6-dichlorophenyl)imino)methyl)-5-chlorophenol (BrcOH), with bivalent ions in a methanol and distil water mixture as solvent in presence of NaOH as base. The structures of the prepared compounds were characterized by spectroscopic techniques (IR and 1H NMR), CHN analysis, and molar conductivity. The M(II) (Ni, Pd and Pt) ions are four-coordinated by a bi-dentate N2O2 donor ligand, forming square planar geometry, whereas the Zn(II) is coordinated as a tetrahedral geometry. The newly synthesized compounds, which include the Schiff base ligand and its complexes, underwent antibacterial screening against E. coli and S. aureus. The results demonstrated a remarkable and noteworthy biological activity of these compounds against these pathogenic bacterial strains. Different binding energies showed good correlation, with Pd showing the strongest binding. Small energy differences indicated high reactivity, with Ni and Pd complexes being the most reactive. Electrophilicity index exhibited electron-accepting properties, with Zn showing the highest reactivity. The dipole moments showed polarity and charge separation, with Pt having the highest polarity. We evaluated the pharmacokinetic properties (ADME) of a ligand and its metal complexes using the Swiss ADME website. The results of the in-silico prediction of physicochemical properties revealed that ten compounds in total adhered to Lipinski's rule.

Benzothiazole-based Schiff base for sensing Ca2+ ions: Synthesis, DFT studies, toxicity evaluation in zebrafish embryo and in silico analysis of MMP-9 inhibition

A new heterocyclic Schiff base, 2-(2-benzo(d)thiazol-2yl)hydrazono)methyl)phenol (BTAZ) synthesized from 2-hydrazinobenzothaizole and salicyclaldehyde was characterized by spectral, mass and single crystal XRD data and subjected to sense Ca2+ ions in methanol–water mixture (1:1, v/v) using UV–visible absorption and fluorescence emission spectral studies. The probe BTAZ showed specific detection of Ca2+ ions in a solution containing various metal ions with a detection limit as low as 5.1 × 10−6 M via photo-induced electron transfer (PET) pathway. The binding stoichiometry between BTAZ and Ca2+ was determined to be 2:1 by Job’s plot method. The stoichiometry and optical properties of both BTAZ and BTAZ-Ca2+ complex showed good correlation with theoretical results based on DFT and TD-DFT calculations. The pharmacological evaluation of the probe BTAZ against bacterial and fungal stains also demonstrated its notable efficacy to control their growth in vitro along with anti-oxidant capabilities. Further, toxicity assay of the probe BTAZ against zebrafish embryo did demonstrate that it is non-toxic to the test model in vivo. Ability of the probe BTAZ to inhibit matrix metalloproteinase-9 (MMP-9) enzyme was analyzed in detail using in silico experiments.

Reducing Solvent Consumption in Reductive Catalytic Fractionation through Lignin Oil Recycling.

Reductive catalytic fractionation (RCF) enables the simultaneous valorization of lignin and carbohydrates in lignocellulosic biomass through solvent-based lignin extraction, followed by depolymerization and catalytic stabilization of the extracted lignin. Process modeling has shown that the use of exogenous organic solvent in RCF is a challenge for economic and environmental feasibility, and previous works proposed that lignin oil, a mixture of lignin-derived monomers and oligomers produced by RCF, can be used as a cosolvent in RCF. Here, we further explore the potential of RCF solvent recycling with lignin oil, extending the feasible lignin oil concentration in the solvent to 100 wt %, relative to the previously demonstrated 0-19 wt % range. Solvents containing up to 80 wt % lignin oil exhibited 83-93% delignification, comparable to 83% delignification with a methanol-water mixture, and notably, using lignin oil solely as a solvent achieved 67% delignification in the absence of water. In additional experiments, applying the RCF solvent recycling approach to ten consecutive RCF reactions resulted in a final lignin oil concentration of 11 wt %, without detrimental impacts on lignin extraction, lignin oil molar mass distribution, aromatic monomer selectivity, and cellulose retention. Overall, this work further demonstrates the potential for using lignin oil as an effective cosolvent in RCF, which can reduce the burden on downstream solvent recovery.

EFFECT OF SNO2 POROUS STRUCTURE ON ITS OPTICAL AND PHOTOELECTROCHEMICAL PROPERTIES IN WATER AND WATER-METHANOL SOLUTIONS

Tin(IV) oxide is a wide-gap semiconductor material that is widely used in photooxidation reactions of organic compounds. However, the relationship between energetic and photoelectrocatalytic properties in the oxidation of small organic molecules has not yet been sufficiently explored. In this work, a series of tin oxides were synthesized using hydrothermal, sol-gel, and template methods. Polystyrene spheres with a size of 250 nm, as well as cetyltrimethylammonium bromide, were used as templates. X-Ray diffraction, low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy and diffuse reflectance spectroscopy methods were used to study the structure, surface composition, optical and energy characteristics. Using photoelectrochemical methods, the potentials of the conduction band and valence band were determined, and photocurrents in aqueous and aqueous-methanol solutions were studied depending on electrode polarization. It is shown that the preparation method (sol-gel or hydrothermal) does not affect the position of energy bands, while the use of a template during synthesis leads to an increase in the average pore diameter in the samples and an increase in photocurrent values in the presence of methanol. It has been established that for template-synthesized samples, the magnitude of photocurrents in a water-methanol mixture increases with an increase in the valence-band potential. The sample prepared by the hydrothermal method using a template showed the highest photocurrent values both in the background electrolyte (17.3 μA/cm2) and in the presence of methanol (26 μA/cm2), compared to the sample prepared without using a template in the electrolyte with the addition of methanol (7.6 μA/cm2) and without it (7.8 μA/cm2).

Dopamine Functionalized TiO2 1D Lepidocrocite Mesoporous Particles As a Sulfur Host

Lithium sulfur batteries are attractive because of their high specific capacities. However, a variety of issues, chiefly polysulfides and the polysulfide shuttle still hinder their development. In our past work we demonstrated a new form of titania-based nanomaterials which we labelled 1 dimensional lepidocrocite nanofilaments (1DLs) as a sulfur (S) host for Li-S batteries1. 1DL is synthesized using a facile bottom-up scalable reaction, directly from commercial 3D bulk solids at ambient pressures and near ambient temperatures2. Moreover, these materials self-assemble into a plethora of microstructures – from individual 1D nanofilaments 5x7 Å2 in cross-section to 2D flakes to mesoscopic particles, all comprised of 1DL - depending on the synthesis and washing parameters. The multitude of structures allows for a variety of applications like electrocatalysis and hydrogen production3. Here we introduce a new structure of 1DLs - mesoporous particles - as S hosts. We further show that by employing a facile, aqueous, 1-step surface functionalization with dopamine – confirmed through changes in the FTIR peaks and an increase in the d-spacing in XRD (inst in Fig 1b) – we increase their interaction with S. The surface functionalization results in a reduction of the 1DL bandgap energy, Eg, to ~1.84 eV, which is a ≈ 50% reduction over un-functionalized 1DL. Additionally, the surface functionalization renders a more conformal coating of S on the 1DL, leading to increased S utilization and interaction with the 1DL, seen in a 20% reduction in of polysulfide shuttle current and 750 mAh.gs -1 at 0.5 C at a loading of 2 mg.cm-2 (seen in Fig 1a and 1b). This is further seen in the increased interactions of the thiosulfate species and Lewis acid-base interactions, shown in our prior work with S and 1DL.References Cardoza, N. A.; Badr, H. O.; Pereira, R.; Barsoum, M. W.; Kalra, V. One-Dimensional, Titania Lepidocrocite-Based Nanofilaments and Their Polysulfide Anchoring Capabilities in Lithium–Sulfur Batteries. ACS Appl. Mater. Interfaces 2023, 15 (44), 50973–50980.Badr, H. O.; Cope, J.; Kono, T.; Torita, T.; Lagunas, F.; Castiel, E.; Klie, R. F.; Barsoum, M. W. Titanium Oxide-Based 1D Nanofilaments, 2D Sheets, and Mesoporous Particles: Synthesis, Characterization, and Ion Intercalation. Matter 2023, 6 (10), 3538–3554.Badr, H. O.; Natu, V.; Neațu, Ștefan; Neațu, F.; Kuncser, A.; Rostas, A. M.; Racey, M.; Barsoum, M. W.; Florea, M. Photo-Stable, 1D-Nanofilaments TiO2-Based Lepidocrocite for Photocatalytic Hydrogen Production in Water-Methanol Mixtures. Matter 2023, 6 (9), 2853–2869. Figure 1

Effect of methanol-water mixtures on the oxidation of n-heptane at low to intermediate temperatures: Experimental and numerical study

Methanol is widely recognized as a carbon-neutral fuel. This work used synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) to study the oxidation process of water/methanol/n-heptane mixes in a jet-stirred reactor (JSR) at a pressure of 1 atm, equivalence ratios (ϕ) of 1 and a temperature range of 500–1100 K. The results of the experiment indicate that the inhibition of n-heptane's oxidation at low temperatures (500–740K) is the primary manifestation of the action of methanol/water mixtures on n-heptane oxidation. The strong interactions among the components of water/methanol/n-heptane mixtures at low temperatures are primarily between methanol and n-heptane. The higher the methanol content, the greater the strength of inhibition of n-heptane oxidation. This inhibitory effect primarily results from the competition of methanol with ˙OH radicals. It is noteworthy that the chemical kinetic interactions between methanol-water mixtures and n-heptane not only manifest changes in the ˙OH radical pools but are also associated with the intermolecular chemical kinetic interactions between peroxyalkyl radicals (ROO˙) and CH3OH.

NiO/vermiculite composites prepared for photocatalytic degradation of methanol-water solution and hydrogen generation

A novel eco-friendly NiO/Vm clay based photocatalysts were synthesized from two vermiculites (Vm1 and Vm2) and nickel(II) nitrate hexahydrate (Ni(NO3)2·6H2O salt precursor by the chemical precipitation without and with the sodium hydroxide (NaOH) or ammonium hydroxide (NH4OH, 28% NH3 in H2O) as precipitation agents (Synthesis A) in comparison with the solid-state thermal decomposition (Synthesis B) at 600 °C. Structural properties of all specimens were characterized by X-ray fluorescence, scanning electron microscopy, X-ray diffraction, infrared (IR) and Raman spectroscopy. The photocatalytic performance of NiO/Vm composites was evaluated under UV radiation (λ = 254 nm) for decomposition of methanol-water to hydrogen over 4-h and the stable yield of hydrogen over the 24-h periods. The NaOH and NH4OH affected the NiO crystallite size and therefore the photocatalytic activity during 4 h. Different 2:1 layer charge of Vm1 (0.82 e−) and Vm2 (0.40 e−) and the specific surface area of Vm1 (about 43 m2/g) and Vm2 (about 34 m2/g) supported H2 yield of 628.2 μmol/gcat. and 596.8 μmol/gcat., close to 657.0 μmol/gcat. produced in the presence of commercial photocatalyst TiO2 Evonik P25. Crystalline NiO precipitated and anchored in NiO/Vm composites contained smaller crystallites than those in free NiO. Vermiculite silica surface supports coverage of NiO by hydrogen bonding to Si-OH groups influencing the geometry of the NiO crystal structure (disorder NiO(X)). The heterojunction with Si-O-Ni bonding, at which electrons transfer from Vm to NiO cause enriching electron density in NiO and favoring its photocatalytic activity. Photocatalytic hydrogen generation from methanol–water mixture at the presence of all specimens indicated the main product H2 and minimum by-products CH4 and CO. The stable hydrogen production for 24 h was confirmed only in the presence NiO/Vm1–24 while maintaining the NiO(X) in small crystallites. The thermal solid-state procedure provided the gradual dehydration of vermiculites and Ni(NO3)2·6H2O to the same amount and crystallinity of NiO in NiO/Vm1 and NiO/Vm2 composites. The results of this work confirm that vermiculites mixed layer structures with different negative layer charge play a dominant role as semiconductors for anchored NiO. The photocatalytic activity of NiO/vermiculite composites can be harnessed to treat wastewater containing organic contaminants.

X-ray crystallography derived diffraction properties of cuprite crystal as revealed by transmission electron microscopy

To produce high crystalline and unified cuprite nano single crystals from copper sulfate pentahydrate a unique bi-polarized methanol-water mixture reduces surface energy and enhances capping efficiency. Exhaustive significance lattice parameters, crystal volume, peak profiling, lattice constant, percent of crystallinity and crystal strain were analyzed by the whole powder pattern fitting (WFPP) Rietveld refinement method. A red shift at 636.0 nm in UV spectrophotometry is associated with a high surface plasmon effect and the zeta potential of 89.0 mV confirms the excellent stability of the cuprite crystal. Crystallographic data, d-spacing 0.25188 nm, lattice parameters a = b = c = 3.78 Å, α = β = γ = 90° of cuprite single crystal was further established by the selected area electron diffraction (SAED) in TEM. Energy dispersive spectroscopy (EDS) reveals the formation of the 100.0 % unified cuprite single crystal.

ЭФФЕКТИВНОСТЬ КОНТАКТНЫХ ТАРЕЛОК РЕКТИФИКАЦИОННЫХ КОЛОНН

The methods of calculating the efficiency of fracking column plates are considered. The efficiency of cap plates was calculated when separating the methanol-water mixture according to two models based on the use of the number of transfer units and mass transfer coefficients

Determination of vanillin compounds in oilseed using solid-phase extraction with ultra-performance liquid chromatography–mass spectrometry

Vanillin, methylvanillin, and ethylvanillin are widely utilized as food flavorings. Oilseeds undergo alterations in their flavor profiles during growth, storage, processing, and oil extraction. To accurately identify the source and quantify the content of these three compounds in oilseeds, we have established an analytical method that utilizes solid-phase extraction coupled with ultra-high performance liquid chromatography–mass spectrometry (UPLC–MS/MS). Oilseed samples were crushed and underwent solvent extraction using water, acetonitrile, and n-hexane. The extracted components were then purified through a liquid chromatography C18 solid-phase column, dried under nitrogen, and reconstituted in a methanol–water mixture (4:1, v/v) prior to UPLC–MS/MS analysis. Quantification of vanillin, methylvanillin, and ethylvanillin was achieved using an external standard method. A total of 34 oilseed samples were analyzed to investigate the origin of vanillin. Among these, 30 samples contained varying concentrations of vanillin, ranging from 51.1 to 1774.7 μg/kg. Furthermore, the presence of vanillin in rapeseed oil confirmed that it originated from the raw rapeseed material. The developed analytical method provides a reliable and valuable tool for screening the authentic source and content of vanillin, methylvanillin, and ethylvanillin in oilseeds, ensuring the quality and integrity of the food supply chain.

Determination of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

Succinic acid and lactic acid have been associated with diarrhea in weaned piglets. The level of succinic acid and lactic acid in serum, meat, and intestinal contents is important to elucidate the mechanism of diarrhea in weaned piglets. A facile method was developed for the quantification of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS). The serum samples underwent protein precipitation with methanol. The meat and intestinal contents were freeze-dried and homogenized using a tissue grinding apparatus. Methanol-water mixture (80:20, v/v) was used for homogenizing the meat, while water was used for homogenizing the intestinal contents. An additional step of protein precipitation with acetonitrile was required for the intestinal contents. The resulting solution was diluted with water before being analyzed by UHPLC/MS/MS. Separation of succinic acid and lactic acid could be achieved within 3min using a Kinetic XB-C18 column. The coefficients of variation for peak areas of succinic acid and lactic acid were less than 5.0%. The established method demonstrated good linearity as indicated by correlation coefficients exceeding 0.996. Additionally, satisfactory recoveries ranging from 88.58% to 108.8% were obtained. The detection limits (RS/N = 3) for succinic acid and lactic acid were determined to be 0.75 ng/mL and 0.02 μg/mL, respectively. This method exhibited high sensitivity, simplicity in operation, and small sample weight, making it suitable for quantitative determination of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat. The method developed will provide valuable technical support in studying the metabolic mechanisms of succinic acid and lactic acid in pigs.

Synthesis, characterization and theoretical studies of tris-cyclometalated rhodium(III) complexes: applications to asymmetric transfer hydrogenation of ketones

This paper presents the synthesis of {Rh[PyCH=C(O)Rn]3} complexes, where R1 = 4-cyanophenyl (L1), R2 = 3-nitrophenyl (L2), and R3 = 4-fluorophenyl (L3). These complexes were derived from the reactions of potassium hexachlororhodate(III) with related pyridinium ylides: PyCH=C(O)C6H4-p-CN (Y1), PyCH=C(O)C6H4-m-NO2 (Y2), and PyCH=C(O)C6H4-p-F (Y3). The reactions were carried out in methanol-water mixtures under mild conditions. The synthesized complexes were characterized using FT-IR, ESI-MS, multinuclear NMR (1H and 13C), and elemental analysis techniques (CHN). Furthermore, these Rh(III) compounds demonstrated excellent catalytic activity, high turnover number (TON), and turnover frequency (TOF) in the hydrogenation of various ketones, resulting in a series of alcohol products with outstanding yields and efficiencies. To investigate the structures of L1, L2, and L3, density function theory (DFT) calculations were performed at the BP86/def2-SVP level of theory. The study employed natural bond orbital analysis (NBO) and energy-decomposition analysis (EDA) to examine the strength and nature of the donor-acceptor bonds between the pyridinium ylide (Y) and Rh fragments in the complexes. Additionally, variations in natural orbitals for chemical valence (NOCV) were investigated.

In-situ synthesis of V2AlC@V2O5/TiO2 immobilized over honeycomb support with vanadium oxide electron transfer mediator for stimulating selective CO2 photoreduction through bi-reforming in a monolith reactor

Photocatalytic CO2 reduction to valuable chemicals and fuels is a practical approach for climate action; however, available photocatalysts and photoreactors are less efficient. In this work, well-designed V2AlC@V2O5 supported TiO2 and immobilized over honeycomb support for CO2 photoreduction in a monolith reactor have been investigated. The catalysts were loaded over the monolithic support using the sol-gel dip-coating method and found promising for higher light absorbance and charge separation. The performance of V2AlC@V2O5/TiO2 composite for photocatalytic CO2 reduction with water and bi-reforming of methanol was performed using a fixed bed and monolith photoreactor. Using V2AlC@V2O5/TiO2 with a fixed bed reactor and methanol–water mixture, a CO yield of 13.75 mmol g−1h−1 was produced, 26.39 and 38.19-fold higher than using water and pristine TiO2, respectively. Similarly, CH4 production was 1.97 and 12.33 folds higher than using water and TiO2 only, whereas, using water, production of H2 was not detected. The higher photoactivity of the composite with methanol was due to efficient photo-induced carrier separation due to the synergistic effect of V2AlC/V2O5 and more production of protons. Using a monolith photoreactor, CH4, CO and H2 production rates of 55.44, 35.51 and 1.638 mmol g−1h−1 were obtained, 166.50, 2.58 and 3.05 times more than those produced using a fixed bed reactor. This significantly higher photoactivity with monolith photoreactor was due to higher photon flux utilization with surface reactions, resulting in more production and utilization of photoinduced charge carriers. The highest QY after five consecutive cycles was 48.374, 25.358 and 1.51 % for CH4, CO and H2, which is 200.5, 2.54 and 3.87 folds higher than using the fixed bed, respectively. This work provides a new approach to designing and fabricating higher efficient and stable photocatalytic system for CO2 recycling, and it can be further employed for other energy-related applications.

Conductometric investigation of nano MnSO4 association parameters and complex formation with glycylglycine in aqueous and methanol-water mixtures: Thermodynamic parameters and potential applications

This study aimed to investigate the ion pair association values and association parameters of nano MnSO4 in water and methanol-water mixtures (20 % and 40 % methanol by mass percentage) at varying temperatures (298.15, 303.15, 308.15, and 313.15 K) using the conductometric technique. Additionally, the parameters for complex formation between nano MnSO4 and glycylglycine as a ligand were determined. The focus was on elucidating the thermodynamic formation parameters for the nano Mn2+-glycylglycine interaction, with particular emphasis on comparing the 1: 1 and 1: 2 (M: L) complexes to understand the complexation behavior more comprehensively. The results indicated that the complexation process was spontaneous, as evidenced by negative ΔGf (formation free energy change) values, which increased with temperature, highlighting the enhanced spontaneity of the process. The findings provide valuable insights into designing new materials and procedures by enhancing our understanding of the complexation behavior of nano MnSO4 with ligands like glycylglycine, thus contributing to advancements in various applications such as chemical synthesis, medicines, and environmental remediation. By elucidating the thermodynamic aspects of these interactions, the study aimed to provide valuable information that could be utilized in practical applications and further research endeavors.

Investigation of Dielectric Constants of Alcohol-Water Mixtures by Microwave (MW) Spectroscopy Technique

Over the last few decades, the utilization of microwave (MW) spectroscopy applications in industry has grown dramatically. This technique is very useful as it gives very important details about alcohol-water mixtures through the measurement of dielectric parameters (Ɛ’ and Ɛ”). This research determined the dielectric parameters (Ɛ’ and Ɛ”) of ethanol-water and methanol-water mixtures for concentration changes from pure water to pure alcohol. The ethanol-water and methanol-water mixture volume fractions of 43% and 44%, respectively, as well as the molar fractions xet≈ 0.20M and xmet ≈ 0.26M, obtained the breaking points of the dielectric parameters (Ɛ’ and Ɛ”).

Porous Anisometric PNIPAM Microgels: Tailored Porous Structure and Thermal Response.

The porous structure of microgels significantly influences their properties and, thus, their suitability for various applications, in particular as building blocks for tissue scaffolds. Porosity is one of the crucial features for microgel-cell interactions and significantly increases the cells' accumulation and proliferation. Consequently, tailoring the porosity of microgels in an effortless way is important but still challenging, especially for nonspherical microgels. This work presents a straightforward procedure to fabricate complex-shaped poly(N-isopropyl acrylamide) (PNIPAM) microgels with tuned porous structures using the so-called cononsolvency effect during microgel polymerization. Therefore, the classical solvent in the reaction solution is exchanged from water to water-methanol mixtures in a stop-flow lithography process. For cylindrical microgels with a higher methanol content during fabrication, a greater degree of collapsing is observed, and their aspect ratio increases. Furthermore, the collapsing and swelling velocities change with the methanol content, indicating a modified porous structure, which is confirmed by electron microscopy micrographs. Furthermore, swelling patterns of the microgel variants occur during cooling, revealing their thermal response as a highly heterogeneous process. These results show a novel procedure to fabricate PNIPAM microgels of any elongated 2D shape with tailored porous structure and thermoresponsiveness by introducing the cononsolvency effect during stop-flow lithographypolymerization.

Non-destructive chromatographic determination of surface area in reverse phase chromatographic columns

One of the critical but underutilized parameters that affect chromatographic separation is an adsorbent surface area (S.A.). We introduce a concept of direct determination of the total surface area of chromatographic columns by utilizing a nondestructive measurement of eluent component excess adsorption isotherm measurement and the application of the Standard Excess Adsorption Isotherm from acetonitrile-water and methanol-water binary mixtures for direct determination of the S.A. in chromatographic columns. This nondestructive technique was used to determine the surface area of five commercial columns, including three core-shell particle type columns (Kinetex-C18, Ascentis C18, and Hallo C18) and in-housemade C18 columns. The traditional low-temperature nitrogen adsorption (LTNA) technique was compared to the novel chromatographic method of nondestructive surface area determination for adsorbents modified with octadecylsilanes. The chromatographically determined surface area was in good agreement with the conventional techniques for all columns used. The difference between the three techniques is less than 10%. Columns were characterized in terms of adsorbent geometry (e.g., pore volume, column void volume, interparticle volume), ligands bonding density, and the amount of the packing material in a chromatographic column.

DEVELOPMENT OF UNIFIED UNIT DESIGN FOR SEPARATION OF HIGHLY MINERALIZED WATER-METHANOL MIXTURE

None of the commodity industries generates as much excitement and profit as oil and gas, which are the main energy carriers. The ability to utilize these key products and their reserves, to hold the strings of business in these areas, determines the path to economic prosperity and the choice of political and economic strategy of the state.The Far North is an area larger than several European countries. It is characterized by extreme climatic conditions, a quarter of all foreign currency revenues to the state budget of Russia comes from this region. 20% of the world’s gas and 90 % of Russian gas and oil are produced here annually. Moreover, the Far North is not only a powerful raw material base of the country today, it is also a kind of guarantor of energy security of the state for many years to come: a quarter of all explored world reserves of natural gas and oil are concentrated here.Resource extraction in the Far North is complicated by a number of external factors, such as low temperatures, difficulties in delivery, installation of equipment at the site, as well as in the operation and repair of process equipment, which in turn leads to new requirements for the design of equipment used for oil and gas production. This paper describes the developed concept of a small-size separation unit for highly mineralized water-methanol mixture (hereinafter referred to as WMM), which is achieved by adopting a number of new technological solutions. The paper also describes the developed methodology of designing a small-size Navy separation plant, which allows to reduce the number of economic costs caused by difficulties in transportation, installation and operation.

Dimension and Flexibility of Polystyrenesulfonate Chains in Methanol-Water.

The influence of the relative permittivity of the solvent medium on the single-chain dimension and flexibility of sodium polystyrenesulfonate chains has been investigated in mixed solvent media of methanol and water using viscosity experiments. Particular attention has been paid to explore the effect of the added low-molar-mass electrolyte. The root-mean-square (rms) radii of gyration of the chains in the unperturbed state have been calculated by applying the Flory model, while the intrinsic persistence lengths by the Benoit-Doty equation on the basis of the Kratky-Porod worm-like chain model. Estimation of the expansion factors for the rms radius of gyration, and the electrostatic persistence length helps evaluate the rms radii of gyration and the total persistence length of polystyrenesulfonate chains in the presence of varying amount of the supporting electrolyte. The polyion chains are highly extended at low ionic strengths but exhibit coil-like behavior with small persistence lengths when an excess of the supporting electrolyte is added in all the methanol-water mixtures investigated. Specifically, in the investigated solvent media, the polystyrenesulfonate chains have been found to shrink by ∼63-65% in the θ-state from their expanded conformation in the presence of 0.0001 mol L-1 NaCl. The chain dimensions pass through a maximum as the medium becomes richer in methanol, which could be explained by the formation and breakup of internal rings involving the polyion chain and water and/or methanol molecules. The intrinsic persistence length of sodium polystyrenesulfonate in a methanol-water mixture containing 0.1 mole fraction of methanol is ca. 1.3 times that in a medium with 0.3 mole fraction of methanol, indicating that flexibility of the polyion depends appreciably on the relative permittivity of the medium.

Charge Transfer Quenching and Maximum of a Liquid-Air Contact Line Moving over a Hydrophobic Surface.

Charge transfer when a hydrophobic fluoropolymer surface comes in contact with salt solutions of water, methanol, and glycerol is investigated. It is found that the charge transfer decreases faster with an increasing fraction of glycerol in water than it does with methanol in water. It is also demonstrated that for both mixtures, the charge transfer increases with the amount of added sodium chloride for small concentrations but then reaches a maximum and subsequently decreases. Surprisingly, this maximum charge transfer shifts toward higher salt concentrations with increasing amount of glycerol in water. However, in water-methanol mixtures, one does not observe a similar shift in charge transfer maximum toward higher salt concentrations. These observations are explained using a model, taking into account the decreased shear distance from the hydrophobic surface for which ions are removed from the electrical double layer due to an interplay of forces acting on the ions.