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Aim and Objectives: To remain safe for further processing or human consumption, study of stressed degradation for the identification of feasible degradants is required. The stability indicating high performance thin layer chromatographic method was developed with Camag HPTLC system. Materials and Methods: Silica C60F254 precoated TLC plates were used as stationary phase for separation of degradation products. The optimized mobile phase system consist of toluene: methanol: diethylamine (7:3:0.1) at 280 nm. Results: From the mass details and IR, NMR interpretation, the plausible structure of alkaline degradation product of drospirenone could be 17a (3-hydroxy propyl)-6ß, 7ß, 15ß, 16ß-dimethylene-5ß-androstane-3ß,5,17ß triol and acidic degradation product of drospirenone could be 3-oxo-15a,16a-dihydro-3'H-cyclopropa[15,16]-17a-pregna-4,6-diene-21,17-carbolactone. Also in silico toxicity studies of the degradation products were performed to assess the toxicity profile of the products using Protox online sever. Conclusion: This analytical method can be considered as an alternative practical and inexpensive method for simple, accurate and efficient quantitative detection of drospirenone in the presence of its degraded products. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the optimization of the operation of a reductive amination (RA) reaction process in a miniplant without an accurate process model using iterative real-time optimization (RTO). The rhodium-catalyzed RA of undecanal with diethylamine produces a tertiary amine from a long-chain aldehyde and is performed in a thermomorphic multiphase system (TMS) to recover and reuse the expensive catalyst efficiently. An iterative RTO method called modifier adaptation with quadratic approximation (MAWQA) is used in combination with guaranteed model adequacy (GMA) to drive the RA process to its optimum iteratively. MAWQA utilizes online measurements to overcome model deficiencies. GMA ensures that the model used in MAWQA satisfies the model adequacy conditions. The optimal operating conditions of the RA process in the miniplant were identified during an experimental run of the plant, thereby validating the applicability and efficiency of MAWQA with GMA. The results illustrate the benefits of process optimization using iterative RTO methods without accurate process models. • Online optimization of a reductive amination process in a mini-plant is performed in the presence of model uncertainty. • An iterative real-time optimization method, modifier adaptation with quadratic approximation is used for optimization. • The issue of undesired input oscillations is avoided by ensuring model adequacy in MAWQA using guaranteed model adequacy. • Experimental results show a smooth convergence to the process optimum. [ABSTRACT FROM AUTHOR]

Azeotropes are boiling liquid mixtures which have identical vapor and liquid compositions. Known as polyazeotropy, azeotropic mixtures may exhibit more than one azeotrope at a given temperature or pressure. While the thermodynamic condition for azeotrope formation in vapor-liquid equilibrium is well established, thermodynamic modeling of mixtures exhibiting polyazeotropy remains challenging and prior modeling studies often failed to satisfactorily correlate the polyazeotropic behavior of associating systems. Based on the association NRTL model, this study presents successful correlation and analysis of double azeotrope formation for three diverse systems: strongly associating methanol + diethylamine binary, weakly associating ammonia + pentafluoroethane binary, and non-associating benzene + hexafluorobenzene binary systems. These systems exhibit polyazeotropic behavior as the temperature increases and approaches their Bancroft points. [ABSTRACT FROM AUTHOR]

The ammonium salts of many drugs have significantly improved the solubility and, accordingly, the bioavailability of medicinal substances in the human body. 5-(4-Hydroxy-2-oxo-2H-chromen-3-yl)-5H-chromeno[2,3-b]pyridines are potential NPY1R ligands, which are attractive for antiobesity treatment. Ammonium salts of 5H-chromeno[2,3-b]pyridines were previously unknown. In this communication, it was found that the four-component reaction of salicylaldehyde, 2-aminoprop-1-ene-1,1,3-tricarbonitrile, 4-Hydroxy-2H-chromen-2-one and amines results in the formation of ammonium salts of 5-(3-chromenyl)-5H-chromeno[2,3-b]pyridines. The structure of these previously unknown compounds was confirmed by means of 1H, 13C NMR and IR spectroscopy, mass spectrometry and elemental analysis.

This work is devoted to study the extraction dearomatization of the kerosene fraction using ionic liquids synthesized on the basis of formic acid and morpholine, as well as acetic acid and diethylamine as a selective solvent. The influence of various factors on the selective purification process has been investigated and the conditions for dearomatization of kerosene have been determined. The group hydrocarbon composition of the dearomatized kerosene raffinate samples by ion-liquid extraction was determined by IR and UV spectral analysis. [ABSTRACT FROM AUTHOR]

The reaction of alkyl 2-(bromozinc)acylates, obtained from ethyl bromoacetate (or butyl 2-bromobutanoate, or butyl 2-bromo-2-methylpropanoate) under the action of zinc, with N-chloro- or N-bromodiethylamine in tetrahydrofuran at 20–25°C under argon for 2 h resulted in the formation of diethyl succinate (or dibutyl 2,3-diethyl succinate, or dibutyl tetramethyl succinate) and diethylamine instead of the expected products of the nucleophilic substitution of the halogen with the 2-alkoxycarbonylalkyl residue. An anion-radical reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Background. Conducting targeted research to improve the quality of metals and their effective use is important in the world, with special attention paid to the following tasks: the use of watersoluble, organic inhibitors to combat scale formation, determination of optimal conditions for the inhibition of corrosion of metals. Purpose. Creation of new highly effective inhibitors based on nitrogen-containing compounds to prevent corrosion of steel in acidic medium and investigation of the mechanism of their action. Methodology. In work gravimetry, IR spectroscopy, X-ray structural analysis as well CE 105 corrosiometer. Originality. Mechanisms of action of organic inhibitors with chromium-containing compounds have been proposed, general regularities have been established affect the effectiveness of steel protection against corrosion in their presence. Findings. The results of the study are that the mechanism of protection of organic inhibitors has depended on their structure and physico-chemical characteristics. [ABSTRACT FROM AUTHOR]

In the present study, the removal of polycyclic aromatic hydrocarbon (PAH) compounds from contaminated soil with solar radiation was investigated. In this context, the effect of diethylamine (DEA) as a photo-sensitizer on the photodegradation of PAH was examined, and the ring distributions of the PAHs were determined. DEA was added to samples at the doses of 1%, 10%, and 20% of dry weight of soil, and samples were kept in ambient air for 24 hours. Concentrations of Σ12PAH in soil samples were detected with Gas Chromatography-Mass Spectrophotometer (GC-MS) as 4382 ng/g dry matter (DM). The total PAH content of the soil decreased by 45% in the presence of sunlight without using DEA. Σ12PAH removal efficiency was at the maximum level of 76% with the addition of 1% DEA to the soil. The increase in the dose of DEA adversely affected the PAH elimination process, and minimum removal ratio (32%) was obtained in the sample containing 20% DEA. The use of DEA has contributed to the elimination of most 3-ring PAH species. Heavy species, 5-6 ring compounds, have not been removed in the presence of sunlight. [ABSTRACT FROM AUTHOR]

The novelty of this work lies in the experimental confirmation that alkylamines react with Nitric oxide (NO) in aqueous solution at room temperature and atmospheric pressure conditions releasing HNO. We combined spectroscopic, electrochemical, and kinetic techniques to describe the reactions intermediates and characterized end products determined by UV–vis, NMR, and GC-MS. Nitrosamine and propene were detected for the reactions of diethylamine and isopropylamine, showing differential mechanisms between primary and secondary alkylamines. Finally, mechanistic analysis using ab-initio methods was performed and compared with the molecular mechanism proposed for the decomposition of NONOates. The results are discussed in the context of the growing interest in the NO/HNO interconversion reactions, required to understand their overlapping and different reactivity. [ABSTRACT FROM AUTHOR]

Of late, the demand for new CO2 adsorbents with high adsorption capacity and stability is growing very fast. Nanofibrous adsorbents are potential materials for such application with most attempts made on carbon nanofibers. In this study, a series of electrospun nanofibrous adsorbents containing amines were prepared using a 3-stage promising approach and tested comparatively for CO2 capture. The preparation of adsorbents involved electrospinning of syndiotactic polypropylene (s-PP) solution, radiation-induced grafting (RIG) of glycidyl methacrylate (GMA) onto electrospun nanofibers, and functionalization of poly-GMA grafted s-PP nanofibrous mats with different amines, including ethanolamine (EA) diethylamine (DEA) and triethylamine (TEA). The effect of different amination parameters: namely, amine concentration, reaction time, temperature, and degree of grafting (DG) on the degree of amination (DA), was evaluated. The nanofibrous mats containing amine were tested for CO2 adsorption in a fixed bed column operated under various parameters such as amine density, amine type, initial CO2 concentration and temperature. The adsorbents recorded CO2 adsorption capacities of 2.87, 2.06, and 0.94 mmol/g for EA-, DEA- and TEA-containing adsorbents, respectively, at 30°C using initial CO2 concentration of 15%. This was coupled with the same order of high amine efficiency of 75, 57, and 31%. Results demonstrated that the nanofibrous adsorbent containing amine had strong potential for CO2 capture application.

A promising method providing the practical implementation of synthesis of AlPO4-41 alumophosphate molecular sieve with high phase purity using boehmite, phosphoric acid, and diethylamine as the template has been proposed. It has been shown that the mixing of the precursors at room temperature leads to the formation of a gel consisting of diethylamine phosphate, an amorphous aluminophosphate, and undissolved boehmite. It has been found that the introduction of the stage of gel aging at 90°C leads to the dominant formation of an amorphous aluminophosphate, the subsequent crystallization of which ensures the formation of high phase purity AlPO4-41 having cubic morphology of crystals with a size of 0.5–1 μm, a BET specific surface area S of 210 m2/g, and a micropore volume of 0.08 cm3/g. [ABSTRACT FROM AUTHOR]

New data on the composition of hexagonal structure III (sH) diethylamine+methane double hydrate are presented. The hydrate was synthesized from methane and aqueous solutions of diethylamine with the molar ratio of diethylamine to water 1:17, 1:20, 1:30, 1:40, and 1:50. In the first case, pure sH hydrate was obtained; in other cases, the mixtures of sH hydrates and methane hydrate were formed. The content of each of the hydrates in mixture as well as the total content of methane in these samples were determined experimentally. The compositions of the formed sH hydrates in all samples were calculated on the basis of these data. It turned out that in all samples, substantial part of large cavities of sH hydrate framework was filled with two diethylamine molecules. To the best of our knowledge, this is the first example of double occupancy of hydrate cavities for gas hydrate synthesized at comparatively low (100 bar) pressure. Multiple filling of the hydrate cavities by guest molecules was previously observed only at pressures above 1000 bar. [ABSTRACT FROM AUTHOR]

The new investigation behind the present work was to envisage microsponges based novel drug delivery system for sustained action of Diclofenac Diethylamine(DDEA) microsponges through Quai-emulsion solvent diffusion method which was engaged using Ethyl cellulose (EC), Eudragit RS100 (ERS) and Poly Vinyl Alcohol (PVA) as carriers with various drug-polymer ratios for the preparation of microsponges. For optimization purposes, several factors are considered in investigation. Characterization techniques followed for the formed microsponges were Fourier Transformer Infrared (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), particle size analysis, along with morphology, drug loading, in vitro and ex vivo drug release. It was found that there is no interaction between the drug-excipients as per DSC and FTIR results. The drug polymer ratio showed great impact on encapsulation efficiency, particle size and drug content. SEM studies showed that morphological microsponges are spherical and porous in nature and with mean particle size of 33 µm. The microsponges were then loaded in gel followed by in vitro drug release studies by modified Franz diffusion cell, in vitro drug release results depicted that microsponges with ethyl cellulose 1:2 drug-polymer ratio were more effective to give extended drug release 76.49±0.261% at the end of 8hrs, which conventional formulation get exhausted earlier by releasing 96.99% drug release at the end of 5 hrs, only topical application of optimized microspongial gel enhanced drug residence time in the skin and therapeutic concentration is maintained for extended period of time, which is possible to show sustained action of drug. [ABSTRACT FROM AUTHOR]

The rotational spectrum of diethyl amine as observed by molecular beam Fourier transform microwave spectroscopy shows splittings due to nitrogen inversion, 14N quadrupole coupling, and internal rotation of the methyl groups. The rotational constants of diethyl amine were determined to be A = 17.61499170(11) GHz, B = 2.103650248(49) GHz, and C = 1.981332501(47) GHz. From the separation between the lowest symmetric and antisymmetric inversion energy level of E = 760.77062(20) MHz a barrier to inversion, using a standard analytical model potential, of 1531 cm-1 (18.31 kJ/mol) was deduced. The 14N quadrupole coupling constants were found to be χaa = 2.67576(37) MHz, χbb - χcc = 4.34144(65) MHz, and |χbc| = 2.9199(92) MHz. The internal rotation of two equivalent methyl groups gave rise to very narrow multiplets; the torsional barrier was determined to be 1051.74(57) cm-1. The experimental results were supplemented by quantum chemical calculations. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Sn(II)/Sn(IV)-doped CeZrO x catalysts were prepared by co-precipitation method. • Diethylamine combustion over CeZrSnO x -(Sn2+) had high activity and N 2 selectivity. • CeZrSnO x -(Sn2+) showed high hydrothermal stability during diethylamine combustion. • The ratio of Sn2+/Sn4+ had a significant impact on the catalytic activity. • The strong acidic sites on the catalyst were conducive to diethylamine combustion. The synthesis of CeZrSnO x by co-precipitation with different valence-state of Sn for diethylamine combustion is novel and intriguing. In this research, the Sn(II)/Sn(IV)-doped CeZrO x catalysts (CeZr(Sn)O x -(Sn2+) and CeZr(Sn)O x -(Sn4+)) were facilely prepared using the co-precipitation method, and their catalytic activities on destruction of diethylamine were evaluated. Detailed characterizations of the catalysts were conducted using X-ray photoelectron spectrometer (XPS), X-ray powder diffraction (XRD), hydrogen-temperature programmed reduction (H 2 -TPR), temperature programmed ammonia desorption (NH 3 -TPD) and so on. For diethylamine combustion, CeZr(Sn)O x -(Sn2+) showed higher activity and nitrogen selectivity than other catalysts, and a high conversion of diethylamine (>90 %) at 250 °C was obtained. After hydrothermal aging treatment, a high conversion (>90 %) and high N 2 selectivity maintained over CeZr(Sn)O x -(Sn2+)-H at 280 °C, indicating high hydrothermal stability of CeZr(Sn)O x -Sn2+. Owe to the large specific surface area (SSA), high oxygen mobility and strong redox performance, and the synergy between metal elements in CeZr(Sn)O x -Sn2+ catalysts, the catalytic properties were enhanced. Moreover, Sn2+/Sn4+ ratio in the catalyst and strong acidic sites on the surface of the catalyst both had significant impacts on the catalytic activity and N 2 selectivity of the catalyst. Finally, the mechanism of diethylamine combustion over CeZr(Sn)O x -Sn2+ was obtained by analyzing the reaction through in-situ diffuse reflection infrared Fourier-transform spectrum (in situ DRIFTS) test. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gas-phase kinetics of Criegee Intermediate CH 2 OO with diethylamine and ethylamine was investigated. • Temperature- and pressure-dependent rate coefficients were measured using a laser-induced fluorescence technique. • Atmospheric implications of CH 2 OO reaction with diethylamine and ethylamine were examined. • The diethylamine and Ethylamine removal rate from the troposphere by CH 2 OO and OH radicals was compared. This paper investigates the pressure and temperature-dependent kinetics of CH 2 OO reacting with diethylamine (DEA) and ethylamine (EA) using the OH laser-induced fluorescence method. Pressure independence was observed within the range of 5.4–75 Torr. The rate coefficients for these reactions at 298 K are (2.49 ± 0.39) × 10−11 and (8.14 ± 1.25) × 10−12 cm3 molecule−1 s−1. The activation energies, determined from experiments conducted between 283 and 328 K, are (−2.01 ± 0.08) and (−1.35 ± 0.02) kcal mol−1. These reactions may contribute to the degradation of DEA and EA under specific environmental conditions. [ABSTRACT FROM AUTHOR]

This article is a highlight of the paper by Isor et al. in this issue of Photochemistry and Photobiology. It describes the photolysis of a dibenzothiophene sulfoximine (bearing N‐phenyl imino and S‐oxide groups) to produce two reactive intermediates in tandem. The sulfoximine undergoes a S–N and S–O photocleavage to release phenyl nitrene and atomic oxygen [O(3P)]. The phenyl nitrene dimerizes to azobenzene or is trapped by diethylamine to reach an azepine. From there, atomic oxygen arises in a secondary photolysis of dibenzothiophene sulfoxide. A computational analysis also reveals that the S–N bond is labile for initial nitrene release, with the secondary release of atomic oxygen by S–O cleavage. Whether future sulfoximine scaffolds can produce the reverse order release of O(3P) then nitrene, or release both simultaneously, is yet to be established. Nonetheless, molecules with dual‐intermediate release, such as coupled photoaffinity labeling and cellular oxidation, are worth pursuing. [ABSTRACT FROM AUTHOR]

[Objectives] To establish an ultra performance convergence chromatography（UPC2） method to determine the content of enantiomers in（R）-2-methoxyethyl1-（1-phenylethyl）-1 H-imidazole-5-carboxylate hydrochloride（ET-26 HCl）. [Methods] Chiralpak? AD-3 chromatographic column（4.6 mm×100 mm, 3 μm） was used, with 0.1% diethylamine methanol solution-supercritical carbon dioxide（1∶9） as mobile phase; flow rate 2.0 mL/min; back pressure 2 000 psi, detection wavelength 240 nm, and column temperature 35 ℃. [Results] ET-26-HCl was completely separated from the enantiomers, and the linear relationship was good; the detection limit was 1.5 μg/mL. [Conclusions] This method is suitable for the determination of the content of enantiomers in ET-26-HCl. [ABSTRACT FROM AUTHOR]

The structural and energetic characteristics of the compounds formed by the reaction of diethylamine (DEA) with protic acids (sulfuric (H2SO4), methanesulfonic (MsOH), trifluoromethanesulfonic (TfOH), and para-toluenesulfonic (TsOH)) were examined using quantum chemical computations (B3LYP-GD3/6-31++G(d,p)). The strength of the hydrogen bonds in the ion pairs formed was quantitatively estimated by the QTAIM theory and NBO analysis. The results of the quantum chemical computations and the obtained thermal (phase transition and decomposition temperatures) and physicochemical (viscosity and conductivity) characteristics indicate that the reactions of DEA with the acids afford salts. The salts with the melting points higher than 100 °C are formed in the case of DEA/OTf(OTs), while protic ionic liquids are produced in the case of DEA/OMs(HSO4). [ABSTRACT FROM AUTHOR]

• A Flow-through cell-microreactor in Attenuated Total Reflection (ATR) mode was used. • Hydrogenation of acetonitrile to amines over a platinum catalyst. • Imine surface intermediate (CH 3 CH = NH) was identified. • A microkinetic mechanism was proposed and kinetic constants were obtained. The mechanism of the acetonitrile hydrogenation to amines over a platinum/alumina catalyst was investigated by in situ infrared spectroscopy. The reaction was studied under realistic conditions -liquid phase using toluene as solvent- using a flow-through cell-microreactor in Attenuated Total Reflection (ATR) mode. Acetonitrile linearly chemisorbed on platinum sites is stepwise hydrogenated to form an imine surface intermediate (CH 3 CH = NH), which in turn is hydrogenated to ethylamine. Using deuterium, the sequential formation of C D and N D bonds was observed. Then, imine intermediate can condense producing diethylamine and triethylamine, giving ammonia as a by-product. The temporal evolution of the IR signals was modeled using a proposed microkinetic mechanism and intrinsic kinetic constants were obtained under chemical control. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Low temperature hydrothermal stability of Cu/SAPO-34 is studied. • The extent of structural destruction is proportional to the crystallite size. • Surface Si content of Cu/SAPO-34 is higher than its averaged bulk Si content. • Surface Si content/Si-O-Al site is proportional to the average crystallite size. • Less Si-O-Al sites dispersed on crystal surface improve the structural stability. Abstract A series of Cu/SAPO-34 catalysts of identical chemical compositions but different crystallite sizes (1–13 μm) was prepared by "one-pot" method. The fresh and low-temperature hydrothermally treated (LHT) catalysts were characterized by a comprehensive set of techniques, including XRF, SEM, EDS, XRD, NMR, BET, XPS, pyridine-FTIR, NH 3 and diethylamine TPD, EPR as well as H 2 -TPR. The reaction rates for NH 3 -SCR were measured under differential conditions and correlated with their physical and chemical properties. All fresh catalysts, regardless of crystallite size, showed the same bulk properties, such as chemical composition, crystallinity, acidity and copper species. After a hydrothermal treatment (96 h at 70 °C with 80% humidity), loss of micropore surface area, micro volume, relative crystallinities, acidity and isolated Cu2+ species was observed on all catalysts, and the extent of decrease was proportional to the average crystallite size. NH 3 -SCR reaction rate suffered a similar decrease with increasing crystallite size. Surface analyses by SEM-ESD, XPS and diethylamine-TPD showed an obvious surface enrichment of Si (and Brønsted acidity) on all fresh catalysts, and the degree of enrichment is also proportional to crystallite size. This surface enrichment of Si-O-Al linkages is thought to be the root cause for the structural vulnerability found on larger crystallite catalysts under LHT conditions. This understanding is entirely consistent with the observation found on the H/SAPO-34 reference materials of the same sizes, where the structural destruction is even more severe after the LHT. A mechanism for structural disintegration for larger Cu/SAPO-34 crystals was proposed, and the genesis of the Si gradient was discussed in the context of crystallization kinetics. [ABSTRACT FROM AUTHOR]

Background. Currently in Uzbekistan there is no production of potassium carbonate, which, as a rule, is purchased in the CIS countries. At the same time, Uzbekistan has explored sufficient reserves of potassium-containing raw materials, which, by technological, economic and, most importantly, rational utilization levels, will provide an opportunity to get their own potassium carbonate to ensure the domestic and foreign consumption markets. In this regard, the development of a method of producing potash based on local raw materials is currently relevant. Purpose. The aim of the work is to study the process of separation of potassium chloride and diethylamine by evaporation in the production of potassium bicarbonate. Methodology. Experiments were performed in a laboratory setup. The evaporation process was carried out at atmospheric pressure in a glass reactor to achieve a given degree of evaporation. The resulting stripped suspension was filtered and determined the amount of solid and liquid phases, depending on the degree of evaporation. The starting material used was a solution of potassium bicarbonate formed during the preparation. In the experiments, the calculated amount of the solution was fed into the reactor-evaporator and the evaporation was performed to achieve a given degree. Originality. For the first time, a physicochemical study of the effect on the process of packaging of solutions processed into potassium bicarbonates of such technological parameters as temperature, diethylamine rate, duration was carried out. Findings. The study revealed that at 147% of DEA with an increase in the time of evaporation from 30 to 45 minutes, the degree of sedimentation of the solid phase at 152 mm Hg and 75°C is from 0.1 - 2.1% and at a pressure of 304 mm. tr.st and 60°C, this figure ranges from 0.5 - 1.2% at 75°C, respectively, is 0.8 - 3.1%. [ABSTRACT FROM AUTHOR]

Abstract The vapor liquid equilibrium data of diethylamine + acetone, acetone + N -methyl pyrrolidone and diethylamine + N -methyl pyrrolidone were measured at 101.3 kPa in this article. Van Ness and Herington test were used to check the experimental data. Three models of the NRTL, UNIQUAC and Wilson were selected to correlate the experimental data. Meanwhile, the binary interaction parameters were regressed with the three models. Root-Mean-Square Deviations and average absolute deviation of equilibrium temperature and mole fraction of vapor phase were calculated between measured value and calculated value. The result indicated that the three models were correlated well with vapor−liquid equilibrium data. Highlights • The isobaric VLE data for DEA + acetone, DEA + NMP and acetone + NMP were measured. • The NRTL and UNIQUAC and Wilson models were applied to correlate the studied system. • The binary interaction parameters (BIP) were obtained for the three models. [ABSTRACT FROM AUTHOR]

[4-(Diethylamino)phenyl]dichlorophosphine synthesized for the first time has reacted with trialkyl orthoformate and ethylene oxide in the presence of ethyl chloroacetate with the formation of phosphorylated formals and ethyl [4-(diethylamino)phenyl](2-chloroethoxy)phosphonyl acetate, a precursor of a new analog of nootropic drug KAPAKh. [ABSTRACT FROM AUTHOR]

The pseudobinary preparative separation of nadolol stereoisomers is performed by simulated moving bed chromatography (SMB). Using the Chiralpak IA adsorbent, a new 25:75:0.1 (v/v/v) methanol‐acetonitrile‐diethylamine solvent composition was selected to perform the experimental SMB separation and compare it with the previous results obtained using pure methanol. Using a 2 g L−1 total feed concentration of an equimolar mixture of the four stereoisomers of nadolol, the more retained component was fully recovered (100% purity and 100% recovery), with a system productivity of 0.77 g L−1 hour−1 and a solvent consumption of 9.62 L g−1. Comparing these results with the ones previously reported using 100:0.1 methanol‐diethylamine solvent composition, this work shows that the 25:75:0.1 methanol‐acetonitrile‐diethylamine is a better alternative for the preparative separation of nadolol stereoisomers by SMB chromatography. These results are confirmed by simulation of the SMB operation for higher feed concentrations, by comparing the performances of the two solvent compositions using the data obtained experimentally through the measurement of the adsorption equilibrium isotherms and the kinetic data obtained for both solvents. The new experimental and simulation results stress out that the performance of the preparative separation can be improved by a careful selection of the solvent composition. [ABSTRACT FROM AUTHOR]

Abstract In this study, 63 compounds measured as 10 individual mixtures containing in each case an active pharmaceutical ingredient and its relevant impurities, and additional set of 7 basic beta blockers were analyzed using ultra-high performance supercritical fluid chromatography with UV and mass spectrometry detection. The separations were accomplished using 8 different stationary phases (diol, diethylamine, 2-picolylamine, 1-aminoanthracene, BEH 2-ethylpyridine, BEH, CSH pentafluorophenyl, and HSS C18 SB), 6 modifiers (methanol, ethanol, isopropanol, methanol/acetonitrile, methanol/ethanol, ethanol/acetonitrile) and 5 additives in methanol (0.1% formic acid, 10 mmol/L ammonium formate, 10 mmol/L ammonium acetate, 0.4% ammonium hydroxide, and 2% water). The resulting chromatograms were evaluated using 6 selected parameters: number of eluted peaks, number of separated peaks, resolution between active pharmaceutical ingredient and following impurity, peak symmetry, peak width at 50% of the peak height, and selectivity. Volatile additives such as ammonium formate, ammonium acetate, and especially ammonium hydroxide provided overall generic approach with very good chromatographic performance. Combined modifier methanol/acetonitrile (1:1) was important for separations of some critical pairs in case of neutral compounds. Diol stationary phase proved its suitability for wide range of applications when the separations of all mixtures were satisfactory on this column, except for vardenafil and beta blockers mixture. HSS C18 SB stationary phase offered unique complementary selectivity especially for analysis of structurally close compounds and/or isomers. Graphical abstract Image 1 Highlights • UHPSFC screening was carried out with 10 real quality control mixtures. • Eight stationary phases were tested using 6 modifiers and 5 additives in methanol. • Evaluating approach consisting of 6 parameters was developed and applied. • Recommendations for generic screening approach in UHPSFC were defined. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nanoplates were exfoliated from flaky iron phosphate dihydrate particles. • Amorphous structure was fabricated within 1 h. • The source material was recycled from steelmaking slag. Abstract Amorphous iron phosphate dihydrate (FePO 4 ·2H 2 O) nanoplates have been for the first time prepared via liquid exfoliation method. The nanoplates were exfoliated from the diethylamine-modified FePO 4 ·2H 2 O that were sourced from recycled steelmaking slag. The obtained nanoplates feature in an average lateral size of 46.76 nm and transversal size of 31.62 nm with an average thickness of 30.4 nm. The amorphous structure was confirmed by material characterisation. The work provides a facile approach to obtain nanostructured iron phosphate that can be beneficial for the applications in energy storage devices and nano-fertilisers. [ABSTRACT FROM AUTHOR]

The title mol­ecular salts, (C18H23N2)2[CdI4], (I), and C18H23N2+·C7H7O4S−·H2O, (II), are stilbazole, or 4-styryl­pyridine, derivatives. The cation, (E)-4-[4-(di­ethyl­amino)­styr­yl]-1-methyl­pyridin-1-ium, has a methyl group attached to pyridine ring and a diethyl amine group attached to the benzene ring. The asymmetric unit of salt (I), comprises one cationic mol­ecule and half a CdI4 dianion. The Cd atom is situated on a twofold rotation axis and has a slightly distorted tetra­hedral coordination sphere. In (II), the anion consists of a 4-meth­oxy­benzene­sulfonate and it crystallizes as a monohydrate. In both salts, the cations adopt an E configuration with respect to the C=C bond and the pyridine and benzene rings are inclined to each other by 10.7 (4)° in (I) and 4.6 (2)° in (II). In the crystals of both salts, the packing is consolidated by offset π–π stacking inter­actions involving the pyridinium and benzene rings, with centroid–centroid distances of 3.627 (4) Å in (I) and 3.614 (3) Å in (II). In the crystal of (II), a pair of 4-meth­oxy­benzene­sulfonate anions are bridged by Owater—HOsulfonate hydrogen bonds, forming loops with an R²4(8) motif. These four-membered units are then linked to the cations by a number of C—HO hydrogen bonds, forming slabs lying parallel to the ab plane. [ABSTRACT FROM AUTHOR]

Highlights • The three evaluation indicators (TAC/second-law efficiency/CO 2 emissions) are employed to rank different configurations. • To compare degree of energy reused, the T-H diagram is employed for different heat-integrated processes. • To rank efficiency for alternative heat utilization processes, the CGCCs and exergy losses at each stage are applied. • The efficient control strategy is developed to eliminate snowball and oscillation effect for partial PSD case. Abstract The steady-state economics and dynamic controllability of heat-integrated pressure-swing distillation (PSD) processes are explored by taking the separation of maximum-boiling azeotrope diethylamine and methanol as demonstrating example. Compared to the conventional process, the B-E configuration (hot stream preheating the feed of high-pressure column) is attractive than others due to reducing 36.83% in energy consumption, 20.49% in CO 2 emissions and 25.69% in total annual cost (TAC) and enhancing 49.48% in thermodynamic efficiency, respectively. Dynamic controllability of the economic efficient backward-integrated processes is also investigated by teaching the terminology of "simultaneous design". The effectiveness of single-end control strategy is determined by the method of feed composition sensitive analysis, and a series of control structures are devised and assessed by the perturbations of feed flowrate and composition. The robust control scheme (CS5) with the ratio strategy to manipulate recycle stream flowrate is constructed to eliminate snowball effect and oscillation phenomena for partially case. It is also used to the combinational heat-integrated processes, and the differences of integral absolute error (IAE) are small between the alternative arrangements, demonstrating that the performance of single-end control scheme with the feedforward strategy of molar ratio reflux-to-feed (R/F) is robust and efficient. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

A flocculant (DES0-0) was synthesized by epichlorohydrin and diethylamine, followed by adding crosslinking agent such as ethylenediamine, diethylenetriamine and triethylenetriamine to obtain the crosslinked polymer DES0-1, DES0-2, DES0-3. The flocculation effect of DES0-1, DES0-2, DES0-3 and PAM was studied by measuring the volume, transmittance and particle size of the clarified solution after flocculation. The results showed that the flocculation effect of triethylenetetramine crosslinked polymer (DES0-3) and PAM was better. Meanwhile, the flocculation effect was more optimistic in the strong alkali environment.

The article raises awareness on some technical and general questions from a physician’s point of view about psychochemicals, a branch of chemical warfare. This awareness was made on the growing debate in the nonmedical press on chemical, bacteriological, and radiological warfare. According to the author, some important conclusions can be reached from available data and general pharmacological principles, although most of the military data are secret and unpublished. Among the potential psychotropic weapons include lysergic acid, mescaline, psilocybine, and methedrine and others that are being secretly developed.

The present study measured the concentrations of aliphatic amines (methylamine (MA), ethylamine (EA), dimethylamine (DMA), diethylamine (DEA), trimethylamine (TMA), and triethylamine (TEA)) in both the aerosols and gas phase at a forested site in Japan, and discussed their seasonal trends and potential sources. These measured amines were more preferentially partitioned into the aerosols than into the gas phase, and mainly distributed into the fine-mode range in the aerosols, although the DMA and TMA were also abundant in the gas phase and the TMA in the aerosols was mainly distributed into the coarse-mode range. The most abundant amine both in the aerosol and gas phase was the DMA, followed by the MA. The MA, EA, DMA, and DEA in the gas phase and aerosols showed higher concentrations in the summer, although the coarse-mode EA concentration did not show the seasonality. The gaseous TMA also showed higher concentrations in the summer, but the coarse-mode TMA increased in the autumn and no seasonality was found in the fine-mode TMA concentrations. The TEA in the gas phase showed higher concentrations in the autumn, but that in the aerosols did not show the seasonality. The decomposition of organic materials in the soil and subsequent volatilization would be an important source of the gaseous MA, DMA, DEA, and TMA. Various biogenic activities can be also expected to be potential sources of the gaseous MA and DMA. The fine-mode MA, EA, DMA, DEA, TMA, and the coarse-mode DMA would be derived from their gaseous form through direct dissolution. Some portions of the fine-mode MA, DMA, and the coarse-mode DMA can be expected to be derived from the primary sources such as biogenic particles like plant debris. The transport of the anthropogenic aerosols can be also expected to contribute to the fine-mode MA. Only the TEA in the gas phase was suggested to be derived from the different sources in the forest from the other five gaseous amines and not contribute to the formation of the fine-mode TEA. It can be considered that the coarse-mode MA, EA, DEA, TMA, TEA, and the fine-mode TEA were affected by the sources independent from the local emission of the gaseous amines, such as the primary sources or the transport from distant sources, although some portions of the coarse-mode MA, EA and DEA might be derived from the dissolution of their gaseous form. Biogenic and pedospheric processes in the forest would be important sources for the amines, especially the gaseous and fine-mode amines, in a forest atmosphere. • The measured six amines were mainly distributed into the fine-mode aerosols. • The most abundant amine in the aerosol and gas phase was the DMA, followed by the MA. • Many of the gaseous and particulate amines showed high concentrations in the summer. • Decomposition of organic matters in the soil was a main source of the gaseous amines. • The fine-mode amines were mainly caused by the gas phase through direct dissolution. [ABSTRACT FROM AUTHOR]

The aim of this work was to compare the effect of reversible post-translational modifications, S-nitrosylation and S-glutathionylation, on the properties of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and to reveal the mechanism of the relationship between these modifications. Comparison of S-nitrosylated and S-glutathionylated GAPDH showed that both modifications inactivate the enzyme and change its spatial structure, decreasing the thermal stability of the protein and increasing its sensitivity to trypsin cleavage. Both modifications are reversible in the presence of dithiothreitol, however, in the presence of reduced glutathione and glutaredoxin 1, the reactivation of S-glutathionylated GAPDH is much slower (10% in 2 h) compared to S-nitrosylated GAPDH (60% in 10 min). This suggests that S-glutathionylation is a much less reversible modification compared to S-nitrosylation. Incubation of HEK 293 T cells in the presence of H 2 O 2 or with the NO donor diethylamine NONOate results in accumulation of sulfenated GAPDH (by data of Western blotting) and S-glutathionylated GAPDH (by data of immunoprecipitation with anti-GSH antibodies). Besides GAPDH, a protein of 45 kDa was found to be sulfenated and S-glutathionylated in the cells treated with H 2 O 2 or NO. This protein was identified as beta-actin. The results of this study confirm the previously proposed hypothesis based on in vitro investigations, according to which S-nitrosylation of the catalytic cysteine residue (Cys152) of GAPDH with subsequent formation of cysteine sulfenic acid at Cys152 may promote its S-glutathionylation in the presence of cellular GSH. Presumably, the mechanism may be valid in the case of beta-actin. [Display omitted] • S-glutathionylation results in loosening of GAPDH globule. • S-Glutathionylated GAPDH is poorly reactivated compared to S-nitrosylated GAPDH. • Treatment of HEK cells with H 2 O 2 or NO leads to sulfenation of GAPDH and actin. • Treatment of cells with H 2 O 2 or NO leads to S-glutathionylation of GAPDH and actin. • Mechanism of protein S-glutathionylation in cells under the action of NO is proposed. [ABSTRACT FROM AUTHOR]

• MnO2@ZIF-8 particles are prepared using sol–gel method and while carbon nanoparticles are prepared via pyrolysis of lighthouse candle. • The detection of diethylamine vapour using MnO 2 @ZIF-8/CNPs composite solid state gas sensor operating at room temperature. • The gas sensor show fast-recovery time, and the sensor is insensitive to a change in humidity. • The study provides a sensing mechanism of diethylamine interaction with the prepared gas sensors using in Situ FTIR-LCR meter. Diethylamine vapor is harmful to people if inhaled or swallowed, as it results in the oxidation of hemoglobin in the body into unwanted methemoglobin, which is unable to transport oxygen in the blood, resulting in reduced blood oxygenation. Lack of blood oxygenation leads to hypoxemia. MnO 2 nanorods, carbon soot, and MnO 2 @ZIF-8 are sensing materials used to prepare solid-state gas sensors that operate at room temperature. The prepared sensing materials were characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The performance of the MnO 2 @ZIF-8 based sensor improved significantly when the carbon soot was introduced into the composite. The effect of the amount of CNPs in the composite on the performance of the sensors was studied. The MnO 2 @ZIF-8/CNPs-based sensor with a 3:1 mass ratio was highly selective towards diethylamine vapor over acetone, methanol, ethanol, and 3-pentanone vapors. An in situ FTIR coupled with LCR meter was used to understand the sensing mechanism of diethylamine vapor and it was found that the sensing mechanism was by deep oxidation of diethylamine to CO 2 , H 2 O, and other molecules. The sensing mechanism was studied by monitored by CO 2 band intensity which was produced from the reaction between the sensing materials and the analyte vapor. As the sensor's exposure time increased the intensity of the CO 2 IR band increased. We observed the direct relationship between the surface reaction rate and the sensor's sensitivity. [ABSTRACT FROM AUTHOR]

Abstract: A synthesis of thin films consisting of hydrogenated silicon oxycarbonitride using high-frequency discharge plasma from a novel organosilicon compound methyltris(diethylamino)silane (MTDEAS) mixed with oxygen and nitrogen are studied. CVD diagrams are obtained as a result of the thermodynamic modeling of the Si-C-N-H-O system in the temperature range from 300 to 1300 K, which makes it possible to optimize the synthesis of film materials such as SiCxNyOz:H. The silicon oxycarbonitride films of various compositions are experimentally obtained in the range of deposition temperatures from 373 to 973 K for different compositions of the initial MTDEAS + O2+ xN2 gas mixture. A change in the chemical composition of the gas mixtures leads to obtaining SiCxNyOz:H films having a large range of functional properties; the refractive index varies from 1.5 to 2.21; the adjustable transparency varies from 92-99.7% in the UV visible and IR spectral regions; and the tunable band gap characteristics vary in the range from 2.5 to 4.5 eV and from 2.9 to 0.7 eV for films grown from MTDEAS + O2+ N2 and MTDEAS + O2+ 2N2 mixtures, respectively. It is shown that the films contain nanocrystals of phases belonging to structures such as Si3 - xCxN4 embedded in the amorphous matrix of hydrogenated silicon oxycarbonitride layers. [ABSTRACT FROM AUTHOR]

In plant cells, many stresses, including low oxygen availability, result in a higher production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These molecules can lead to redox-dependent post-translational modification of proteins Cys residues. Here, we studied the effect of different redox modifications on alcohol dehydrogenase (ADH) from Arabidopsis thaliana. ADH catalyzes the last step of the ethanol fermentation pathway used by plants to cope with energy deficiency during hypoxic stress. Arabidopsis suspension cell cultures showed decreased ADH activity upon exposure to H2O2, but not to the thiol oxidizing agent diamide. We purified recombinant ADH and observed a significant decrease in the enzyme activity by treatments with H2O2 and diethylamine NONOate (DEA/NO). Treatments leading to the formation of a disulfide bond between ADH and glutathione (protein S-glutathionylation) had no negative effect on the enzyme activity. LC-MS/MS analysis showed that Cys47 and Cys243 could make a stable disulfide bond with glutathione, suggesting redox sensitivity of these residues. Mutation of ADH Cys47 to Ser caused an almost complete loss of the enzyme activity while the Cys243 to Ser mutant had increased specific activity. Incubation of ADH with NAD+ or NADH prevented inhibition of the enzyme by H2O2 or DEA/NO. These results suggest that binding of ADH with its cofactors may limit availability of Cys residues to redox modifications. Our study demonstrates that ADH from A. thaliana is subject to different redox modifications. Implications of ADH sensitivity to ROS and RNS during hypoxic stress conditions are discussed. [ABSTRACT FROM AUTHOR]

Hydrophobic submicron hybrid silica particles were spontaneously formed in the mixture of tetraethylorthosilicate (TEOS) and hexyltrimethoxysilane (HTMS) dissolved in diethylamine, which works as a catalytic Lewis basic amphiphilic reaction solvent. The obtained hybrid silica particles were stably dispersed in non-polar solvent such as hexane in the form of the primary-particle dispersion. The solvent diethylamine functioned not only as the catalyst for the silanol polycondensation but also as a superior dispersant for the primary-particle dispersion of the hydrophobic hybrid silica particles throughout the formation process. After the addition of TEOS, HTMS and water in diethylamine, the particle nucleation was promoted the ultrasonication for 30 s. Then, the uniform-sized submicron hydrophobic hybrid silica particles were spontaneously formed after the dispersion of the nuclear was kept still for 24 h. The surface of the hybrid silica particles became increasingly hydrophobic. This is because of the higher density of the non-polar pendant groups (hexyl groups) in the vicinity of the surface, which results from the lower reactivity of trifunctional HTMS than that of tetrafunctional TEOS. The merits of using diethylamine are summarized as follows; 1) Since diethylamine strongly catalyzes silanol condensation, the particle surface was thoroughly hydrophobized. 2) Since the hydrophobized particle had good affinity with diethylamine, the hybrid silica particles remained stably dispersed in it. Furthermore, even after the hybrid silica particles are air-dried, they are redispersed in hexane in the form of the primary-particle dispersed. [ABSTRACT FROM AUTHOR]

To achieve enhanced electron field emission, diamond-graphite nanohybrid films are deposited on Si substrates by means of a microwave plasma chemical vapor deposition (MPCVD) reactor. Liquid diethylamine is used as a sole reactive source. An increase of deposition temperature from 730 °C to 830 °C leads to remarkable changes of morphology and microstructure of diamond-graphite nanohybrid films, namely from a typical planar ultrananocrystalline diamond (UNCD) film at 730 °C to a novel nanocrystalline diamond/graphene nanowall (ND/GNW) film at 830 °C. The electrical conductivity of a ND/GNW film is measured to be 762.4 Ω −1 ·cm −1 , while for a UNCD film it is 18.0 Ω −1 ·cm −1 . Moreover, the electron field emission is significantly enhanced on a ND/GNW film. With an applied electrical field of 9.9 V μm −1 its emission current density is 1.6 mA cm −2 , 8-time larger than that for a UNCD film. The possible electron emission mechanism is then discussed based on the Fowler-Nordheim theory. This work offers a simple way to alter effectively the microstructures of sp 2 /sp 3 nanohybrid films that benefit greatly to develop carbon-based field emission cold cathodes featuring high performance. [ABSTRACT FROM AUTHOR]

Diethylamine is the smallest and simplest molecule that features a supramolecular helix as its lowest energy aggregate. Structural studies and large scale sampling simulations show that the helical arrangement is more stable than cyclic structures, which are the dominant species for other small hydrogen bonding molecules. [ABSTRACT FROM AUTHOR]

The reaction of μ-carbidodimeric iron(IV) tetra-4-tert-butylphthalocyaninate with nitrogenous bases (imidazole and its derivatives, pyridine, diethylamine), which involves formation of donor‒acceptor complexes with a preserved dimeric structure, was studied by spectral methods. The composition of such molecular complexes and their comparative stability were determined. The coordination power of μ- carbidodimeric iron(IV) tetra-4-tert-butylphthalocyaninate was found to depend on the nature of the nitrogenous base and macrocycle. Quantum-chemical modeling of the coordination reaction was performed. The energetic and geometric characteristics of the donor‒acceptor complexes were obtained. The composition of the reaction products was shown to be affected of the degree of deformation of the macrocycle. [ABSTRACT FROM AUTHOR]

A concise one-pot three-component reaction of organic halides, terminal acetylenes, and sodium azide provided an efficient route for the synthesis of 1,2,3-triazoles. A variety of 1,2,3-triazoles were prepared in good to excellent yields with green solvent glycerol. This procedure used CuI and diethylamine, which are two easily available reagents as the new catalytic system at room temperature. [ABSTRACT FROM AUTHOR]