Compounds In Liquid Phase Research Articles

Enhancement of biomethane production from coal by supercritical CO2 extraction

The recalcitrant nature of organic matter in coal presents a significant challenge to biomethane production. Supercritical CO2 has gained considerable attention for its unique extraction capabilities. This study uses four coal samples of varying ranks to investigate the promotion mechanism of biomethane production by supercritical CO2 extraction in combination with anaerobic digestion (Sc-AD). Methanogenic potential oxygenated functional groups, intermediate liquid phase products, microbial community structure, and methanogenic metabolic pathways were analyzed between Sc-AD and AD systems. The study found that microorganisms in the Sc-AD system produce more extracellular polymers that enhance the content of aromatic proteins in the anaerobic digestion system. The liquid-phase compounds extracted by supercritical CO2 were consumed by fermentative acidogenic bacteria, significantly increasing the metabolic efficiency of intermediates such as indole and catechol. The reduction in the relative content of carbonyl and carboxyl groups on the coal surface in the Sc-AD system was attributed to the successive attacks by supercritical CO2 and microorganisms on the coal surface. This resulted in the shedding of carbonyl and carboxyl groups from the coal surface, which were then utilized to synthesize small molecule acids. In contrast, hydroxyl groups were retained in the coal. The Sc-AD system exhibited a more stable and efficient microbial community structure in methane production than the AD system. The study demonstrated that supercritical CO2 extraction is a potential method for enhancing CBM recovery and CO2 reduction.

THEORETICAL AND EXPERIMENTAL APPROACHES IN THE STUDY OF ELECTROCHEMICAL AND THERMODYNAMIC PROPERTIES OF POLYFUNCTIONAL ORGANIC COMPOUNDS IN LIQUID-PHASE AND HETEROPHASE SYSTEMS

The publication reflects the experimental substantiation and fundamental development of some important ideas of the theory of the mutual influence of functional substitution in complex molecules of macrocyclic and chelating compounds on their coordination, solvation and redox properties, as well as the formation of algorithms for searching useful functions of these compounds. Researchers of the Analytical Chemistry Department of the Ivanovo State University of Chemistry and Technology have been studying the electrochemical and thermodynamic behavior of porphyrins, complexones, amino acids, peptides and the corresponding complexes with d- and f-metal ions, their influence on coordination, solvation and catalytic processes for a number of years. The results obtained together with the literature data are discussed in the review. For citation: Bazanov M.I., Berezina N.M., Gridchin S.N., Krutova O.N., Gorboletova G.G., Bychkova S.A., Lytkin A.I., Chernyavskaya N.V., Chernikov V.V., Volkov A.V. Theoretical and experimental approaches in the study of electrochemical and thermodynamic properties of polyfunctional organic compounds in liquid-phase and heterophase systems. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 7. P. 98-110. DOI: 10.6060/ivkkt.20236607. 6839j.

Mishik A. Kazaryan (1948–2020) – One of the pioneers of Russian hydrogen energetics

In 2018, Mishik Airazatovich Kazaryan received the highest award of the International Association for Alternative Energy and Ecology - Order of Antoine de Saint-Exupéry “For Improving the Quality of Life on the Planet of People” (IAAEE) on nominating the Award Committee of the Editorial Board of the International Scientific Journal for Alternative Energy and Ecology (ISJAEE). The award was given for his outstanding contribution to development of alternative energetics and ecology. M.A. Kazaryan's prominent contribution to the development of alternative energetics and ecology is based on his pioneering works in the field of development of methods for producing hydrogen as environmentally friendly safe fuel, as well as works in the field of processing organic compounds by various physical methods. As a part of joint research with colleagues from Lebedev Physical Institute of RAS (LPI), M.A. Kazaryan participated in creation of new methods for producing hydrogen from various chemical compounds. The method of conversion of liquid-phase compounds in plasma discharges under the influence of intensive ultrasonic cavitation occupies a special place. In the course of these works, it is shown that low-temperature plasma initiated in liquid-phase media in discharge between electrodes is able to effectively decompose hydrogen-containing molecules of organic compounds and form gaseous products where the part of hydrogen is more than 90%. Estimations of energy efficiency calculated taking into account hydrogen combustion heat and initial substances, as well as electricity costs, showed an efficiency level of about 60–70% in depending on the composition of the starting mixture. Another notable contribution of M.A. Kazaryan to the development of alternative energetics was the work on the optimization and justification of technological and structural parameters of energy discharge devices based on high-voltage pulse-periodic discharge for creating a reactor for plasmachemical processing of polymer wastes into hydrogen and other valuable compounds.

Modelling of photo-electrocatalytic behaviour of TiO2 nanotubes under solar light irradiation

A mathematical model of the photo-electrochemical processes occurring during irradiation with solar light has been implemented, to evaluate the optimal geometry of TiO2 nanotubular structures for the different applications. The model accounts for generation and recombination of charge carriers, as well as for transport phenomena in solid phase. Electrochemical reactions at the surface and chemical processes in liquid phase are also modelled. The solar irradiation has been discretised in the UV and visible range, and adsorption coefficients as a function of the wavelength have been used. The model has been solved for oxidation of water, as well as for oxidation of organic compounds with different reactivity. The effect of such variables as light intensity, electric potential and reactivity of the organic compounds on space distribution of charge carriers in solid phase, oxygenated radicals and organic compounds in liquid phase, have been determined. The model provides a versatile tool to assess the performances of nanotubular electrodes at microscale and makes possible the optimal design of the nanostructure.

Sorbitol transformation into biofuels over bimetallic platinum based catalysts supported on SiO2-Al2O3 – Effect of the nature of the second metal

Sorbitol hydrogenolysis in aqueous medium was carried out over Pt based catalysts supported on SiO2-Al2O3 and modified by a second metal (Re, Ir, Rh and Pd). The catalysts were synthetized by two preparation methods, co-impregnation and successive impregnations. The metallic properties of these catalysts were characterized by transmission electron microscopy and X-ray diffraction, H2 chemisorption, temperature programmed reduction and by the model reaction in gas phase of cyclohexane dehydrogenation. The acidic properties were characterized by ammonia thermodesorption and by the model reaction in gas phase of 3,3-dimethyl-1-butene. The catalytic performances were compared to those of corresponding monometallic catalysts under hydrothermal conditions, in a batch reactor at 240 °C under 60 bar H2 pressure. The main products were poly- and mono‑oxygenated compounds in liquid phase and hydrocarbons in gaseous phase. Among the studied modifiers, Re allowed to promote the catalytic performances of Pt leading to a synergistic effect for the transformation of sorbitol into liquid fuels (hexane). The highest efficiency of the Re-Pt/SiO2-Al2O3 catalyst prepared by co-impregnation was explained by an optimal balance between the acidic and metallic functions constituted of bimetallic particles of small size dispersed on the acidic support.

Reversible Photocuring of Liquid Hexa-Anthracene Compounds for Adhesive Applications

ABSTRACTReworkable adhesion of glass plates was demonstrated using colourless adhesives. This was achieved using anthracene-terminated liquid compounds with hexamer structures (2500 g mol−1) as adhesives, which are photo-crosslinkable and thermo-degradable materials. It was found that the substitution position at the anthracene was important to obtain liquid-phase compounds at room temperature. However, although the compounds were liquid, they were too viscous to be used as adhesive. Therefore, they were mixed with 25 wt.% of dibutyl phthalate to increase fluidity. The liquid mixture could then be applied to the glass substrates without further modification, and was curable via photodimerisation of anthracene moieties to tightly attach the glass substrates together. The cured material was stable up to 120°C, but it returned to the original liquid state at room temperature after heating at 180°C, resulting in the detachment of the substrates without applying any strong force. The cycles of the curing and liquefying processes was reproducible for at least five consecutive times.

Accurate prediction of liquid phase equilibrium adsorption of sulfur compound

This work highlights the application of two types of artificial neural networks namely PSO-RBF and CSA-LSSVM for prediction of equilibrium adsorption of sulfur compound in liquid phase of hydrocarbon solution of isotherm batch systems. The precision and reliability of developed models were investigated by various graphical and statistical approaches. Initial sulfur concentration, utilized adsorbent weights, molecular weights and densities of solvent and solute, average size of adsorbent particle, Si/Al ratio of adsorbent and temperature were used as input parameters of models and the amount of adsorption was considered as the output. Results show that the predictions of CSA-LSSVM model are a little more precise and reliable compared to the outcomes of PSO-RBF model. The overall values of R2 and AARD% for CSA-LSSVM model were 0.9920 and 0.55 that show precision and robustness of the applied model.

Evaluation of strategies for second generation bioethanol production from fast growing biomass Paulownia within a biorefinery scheme

Fast-growing and short-rotation biomass is identified as glucan-rich feedstock to be used for bioenergy purposes. For the first time to our knowledge, fast growing biomass (Paulownia tomentosa) was evaluated for bioethanol production in a biorefinery scheme. For that, Paulownia wood was subjected to autohydrolysis pretreatment under severity (S0) conditions in the range of 3.31–5.16. The effect of this treatment on its fractionation was evaluated by means of hemicelluloses solubilization as hemicellulose-derived compounds in liquid phase and enzymatic hydrolysis of glucan (remained in the solid phase) into glucose. A xylose and xylooligosaccharides concentration of 17.5g/L was obtained at S0=3.99 which corresponds to complete xylan solubilization. On the other hand, glucose yield of enzymatic hydrolysis increased up to reach 99% at S0=4.82. In addition, separate and simultaneous saccharification and fermentation assays (SHF and SSF) of autohydrolyzed Paulownia were compared for ethanol production. An increase of 47% in ethanol concentration was obtained by SHF in comparison with results achieved by SSF for Paulownia treated at S0=4.19. In SSF, Paulownia was successfully converted into ethanol (52.7g/L which corresponded to 80% of ethanol yield) operating at 20% solid loadings and S0=4.72. Energy analysis of results obtained in this work showed that 83% of energy respect to raw material can be recovered considering the ethanol and the combustion of residual lignin. This work provides a feasible process for bioethanol production using fast growing specie which could enrich the feedstock needs for biofuels sector.

Sorbitol transformation over bimetallic Ru-Pt/SiO2-Al2O3 catalysts: Effect of the preparation method

Sorbitol hydrogenolysis in aqueous medium was carried out over Ru-Pt based catalysts supported on SiO2-Al2O3 and synthetized by three preparation methods (co-impregnation, successive impregnations or a surface redox deposition). These catalysts were characterized by N2 isothermal adsorption desorption, transmission electron microscopy, H2 chemisorption, temperature programmed reduction and by the model reaction in gas phase of cyclohexane dehydrogenation. The catalytic performances were compared to those of monometallic catalysts (Pt/SiO2-Al2O3 and Ru/SiO2-Al2O3) under hydrothermal conditions, in a batch reactor at 240°C under 60bar H2 pressure. The main products were poly- and mono-oxygenated compounds in liquid phase and hydrocarbons in gaseous phase. The best yield of hydrocarbons was obtained in the presence of Ru-Pt bimetallic catalyst prepared by successive impregnations, for which a synergetic effect was observed. This effect can be explained by the existence of bimetallic particles of small size favoring an electronic exchange from Ru to Pt. Under the experimental conditions used in this study, it appeared that the reaction pathway of sorbitol transformation was not the same on Pt- or Ru-based catalysts.

Comprehensive monitoring of MEA degradation in a post-combustion CO2 capture pilot plant with identification of novel degradation products in gaseous effluents

A pilot plant campaign was performed to study MEA degradation in CO2 capture conditions and anticipate potential degradation products emissions to the atmosphere in industrial case. Aqueous 30% wt MEA was cycled between absorption and regeneration steps during 1700h in the presence of a synthetic flue gas containing 81% of N2, 14% of CO2, 5% of O2, 97ppm of NO, 9ppm of SO2 and 5ppm of NO2. Specific methods (sampling, sample conditioning and analysis) were developed to improve degradation products identification and to provide a quantification of targeted compounds in liquid phase and above all in absorber and stripper gas effluents. Especially, trace elements were detected in liquid phase thanks to Head Space-Solid Phase MicroExtraction (HS-SPME) and liquid–liquid extraction with ChemElut cartridges and in gas phase thanks to adsorbent tubes of different type: Sep-Pak® for aldehydes and ketones, Orbo 60 for N-nitrosodimethylamine, Tenax and active charcoal for non-specific adsorption. 32 degradation products were identified in liquid phase and 38 in gas phase, 17 of which for the first time, especially derivatives of pyridine and oxazolidine, 1H-pyrrole and a new nitrosamine, the N-nitroso-2-methyl-oxazolidine.

THE MATRIX EFFECT OF TUNA AND MAHI-MAHI ON BIOGENIC AMINE DETECTION

Method of standard addition (MSA) is used to account for and quantify matrix effect. In this study, MSA was used to analyze the matrix effect of mahi-mahi and tuna in respect to biogenic amine detection. Two different detection methods were used in conjunction with the MSA procedure: a colorimetric strip that detects volatile biogenic amines and a histamine-specific ELISA (enzyme-linked immunosorbant assay), which detects histamine in the liquid phase. Trained sensory experts were utilized to grade mahi-mahi and tuna. The grading system acted as a measure of fish quality. A biogenic amine cocktail was created to act as the standard spike for the MSA procedure. It contained histamine and other biogenic amine compounds of varying volatility that are present in nature. The ELISA-MSA showed a clear correlation between increase in histamine and a lower quality sample (higher numerical grade). The colorimetric strips did not have a clear correlation between biogenic amine content and grade. Comparing the two methods demonstrates that the matrix effect of the tuna and mahi-mahi is likely more prominent with gas phase compounds than liquid phase compounds.

A SEM Record of Proteins-Derived Microcellular Silicon Carbide Foams

Protein rigid foams based on albumin coreacted with camphor and an aldehyde were converted into silicon carbide (SiC) foams. This was carried out by putting albumin-derived template foams in contact with silicon compounds in liquid phase and calcinating the mix obtained at a relatively low temperature of 500°C to eliminate the protein and leave the SiC foam. The transformation was followed by scanning electron microscopy (SEM) from the natural albumin foams to the gel obtained by infi ltrating them with tetraethyl orthosilicate (TEOS) and to the appearance of the SiC foams after calcination. X-ray diffraction (XRD) and Raman spectra were done to characterise the resulting foam.

Fifty years of desorption ionization of nonvolatile compounds

During the past 50 years mass spectrometry has advanced from a small molecule method to one critical to understanding biological processes. The ability to analyze compounds as large as protein complexes did not happen with any single invention, but occurred in steps. Thus, electrospray ionization can be traced to Zeleny (1917) and Dole (1968), but also to Colby and Evans (1973) with the demonstration of electrohydrodynamic ionization of organic compounds. Likewise, matrix-assisted laser desorption/ionization can be traced to early work with laser desorption by Mumma and Vastola (1972), and the importance of a matrix in analysis of nonvolatile compounds can be attributed to Barber et al. with the introduction of fast atom bombardment (1981). Here, we look back over the past 50 years at the development of desorption methods for the analysis of nonvolatile compounds and the associated attempts at understanding the mechanism by which solid or liquid phase compounds are converted to gas-phase ions.

Gas phase glycerol conversion over lanthanum based catalysts: LaNiO3 and La2O3

The catalytic performance of lanthanum based catalysts: LaNiO3 and La2O3 were evaluated in the gas-phase transformation of glycerol. The reaction was investigated in the temperature range of 300–700°C. At 400 and 500°C, the production of compounds in liquid phase is favored while at high temperature gases such as carbon monoxide, carbon dioxide and hydrogen are mainly formed. The basic catalysts used in this study favor the production of hydroxyacetone. Additionally 1,2 propanediol, methanol and ethylene glycol were formed in significant amount. The perovskite LaNiO3 and La2O3 show no significant deactivation during 10h at 400°C, the selectivity to hydroxyacetone only slightly decreased with time on stream most probably due to the formation of heavy products. The catalysts were characterized before and after reaction (XRD, TGA, CO2-TPD) showing that LaNiO3 was partially reduced into LaNiO2.5 during reaction at 400°C. It is suggested that strong basic sites of La2O3 compared to LaNiO3 are particularly active to produce methanol through glyceraldehyde but also acetaldehyde, propionaldehyde and acetone.

CALCULATION OF Mn2+ IONS REMOVAL WITH SORBENT-CATALYST USING

New sorbent-catalyst using in water treatment technology from manganese compounds allows get qualitative water that satisfies present quality requirements. Salt content of doubly charged ions such as calcium, magnesium and sulphates on sorbent-catalyst efficiency in article was explored. It was established that singly ions of sodium chlorides and doubly charged hardness ions influence on residual concentration of manganese compounds in liquid phase. It was found that influence of doubly charged ions on water purification form manganese compounds with sorbent-catalyst using was substantial. Calcium and potassium carbonates leaching from sorbent-catalyst was confirmed. The solution pH value increased to optimal for manganese compounds removal range within sorbent-catalyst contact time. Experimental data with fitted coefficients were described by proposed theoretical model. The theoretical model makes it possible to calculate pH value, solution air oxygen saturation and salt content influence on water treatment from manganese compounds with sorbent-catalyst using.

The behaviors and fate of polycyclic aromatic hydrocarbons (PAHs) in a coking wastewater treatment plant

The occurrence, behaviors and fate of 18 PAHs were investigated in a coking wastewater treatment plant in Songshan coking plant, located in Shaoguan, Guangdong Province of China. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent, sludge and gas samples. In raw coking wastewater, high molecular weight (MW) PAHs were the dominant compounds, while 3–6 ring PAHs predominated in the final effluent. The dominant compounds in gas samples were phenathrene, fluoranthene and pyrene, while they were fluoranthene, pyrene, chrysene and benzo[k]fluoranthene for sludge. The process achieved over 97% removal for all the PAHs, 47–92% of eliminations of these target compounds in liquid phase were achieved in biological stage. Different behaviors of PAHs were observed in the primary tank, anaerobic tank, aerobic tank, hydrolytic tank and coagulation tank units, while heavier and lower ones were mainly removed in anaerobic tank and aerobic tanks, respectively. Regarding the fate of PAHs, calculated fractions of mass losses for low MW PAHs due to transformation and adsorption to sludge accounted for 15–50% and 24–49%, respectively, while the rest was less than 1%. For high MW PAHs, the mass losses were mainly due to adsorption to sludge and separation with tar (contributing 56–76% and 22–39%, respectively), and the removal through transformation was less.

Additivity methods for prediction of thermochemical properties. The Laidler method revisited. 2. Hydrocarbons including substituted cyclic compounds

A revised parameterization of the extended Laidler method for predicting standard molar enthalpies of atomization and standard molar enthalpies of formation at T = 298.15 K for several families of hydrocarbons (alkanes, alkenes, alkynes, polyenes, poly-ynes, cycloalkanes, substituted cycloalkanes, cycloalkenes, substituted cycloalkenes, benzene derivatives, and bi and polyphenyls) is presented. Data for a total of 265 gas-phase and 242 liquid-phase compounds were used for the calculation of the parameters. Comparison of the experimental values with those obtained using the additive scheme led to an average absolute difference of 0.73 kJ · mol −1 for the gas-phase standard molar enthalpy of formation and 0.79 kJ · mol −1 for the liquid-phase standard molar enthalpy of formation. The database used to establish the parameters was carefully reviewed by using, whenever possible, the original publications. A worksheet to simplify the calculation of standard molar enthalpies of formation and standard molar enthalpies of atomization at T = 298.15 K based on the extended Laidler parameters defined in this paper is provided as supplementary material.

Reactive uptake studies of NO3 and N2O5 on alkenoic acid, alkanoate, and polyalcohol substrates to probe nighttime aerosol chemistry

Heterogeneous reactions between NO3 and N2O5 and diethyl sebacate (DES), glycerol, oleic acid (OA), linoleic acid (LA), and conjugated linoleic acid (CLA) were studied to understand better nighttime aerosol chemistry. The reactive uptake coefficient of NO3 on the liquid alkenoic acids (OA, LA, and CLA) was found to be >0.07, which is higher than previous results for unsaturated organics, including alkenoic acids. This reaction could potentially be an important loss process of particle-phase unsaturated organic compounds in the atmosphere and in laboratory secondary organic aerosol studies. The reactive uptake coefficient of N2O5 on liquid glycerol was also found to be relatively large with a value of (3.2-8.5)x10(-4), suggesting that N2O5 heterogeneous reactions with alcohols may also be atmospherically relevant. For all measurements with OA, CLA, and DES, the reactive uptake coefficients decreased significantly upon freezing. One possible explanation is that the liquid reaction is due to both a surface reaction and a bulk reaction and that the freezing process significantly decreases the importance of any bulk reactions. NO3 reactive uptake coefficients for liquid-phase compounds decreased in magnitude in the order: alkenoic acids>DES>glycerol. This is different compared to previous gas-phase studies and the difference may be due to the large viscosity of glycerol compared to the other organic compounds studied. N2O5 reactive uptake coefficients for liquid-phase compounds decreased in magnitude in the order: glycerol>LA>DES congruent with OA congruent with CLA.

Prediction of direct chemiluminescence behavior of organic compounds in liquid phase based on QSPR method

Based on the quantitative structure–property relationship study, molecular topological index was used to construct a discriminate function of chemiluminescence with linear discriminant analysis. The proposed discriminate function was applied to theoretically predict the chemiluminescence behavior of 256 organic compounds when reacted with common oxidant in liquid phase with a success probability of higher than 94.5%. The present work would give an idea to quickly develop a suitable direct chemiluminescent analytical method in a very simple way.

Synthesis, characterization and catalytic activity of ordered SBA-15 materials containing high loading of diamine functional groups

Diamine-functionalized mesoporous SBA-15 materials have been synthesized by co-condensation of tetraethylorthosilicate (TEOS) with [3-(2-aminoethyl aminopropyl)]trimethoxysilane (ATMS) using amphiphilic block copolymer P123 as pore-directing agent under the aid of inorganic salt NaCl and with prehydrolysis of TEOS prior to the addition of organosiloxane. The functionalized materials have hexagonal mesostructure ordering, narrow pore-size distribution with diameter around 60 Å, and high loadings of amino groups (up to 3.49 mmol g −1). Prehydrolysis of TEOS was a key step for preparation of well-ordered mesoporous materials with amino functionalities. Inorganic salt had great influence on the ordering of mesostructure and the morphology of the resultant materials. The diamine-functionalized materials showed better catalytic performance than the aminopropyl-functionalized counterpart in the Knoevenagel reaction of benzaldehyde with ethyl cynoacetate to form α,β-unsaturated compound in liquid phase.