The effect of solid adsorbents in Triethanolamine (TEA) solution for enhanced CO2 absorption rate

This study aimed to investigate CO₂ absorption using chemical solvent of amine H₂O-TEA-CO₂ in presence of activated carbon (AC) particles. The studied experimental range includes the temperature in range of 293–333 K, pressure in range of 3.5–9.5 bar, the concentration of solvents in range of 2.5–8.5 wt%, and amount of activated carbon in range of 0.3–0.9 kg/m³. The central composite design (CCD) with four parameters of temperature, pressure, amine concentration, and active carbon was applied in 5 levels. The physical solubility CO₂ in amine solutions decreases with the increasing temperature that indicates the process is exothermic. The optimal values of temperature, pressure, concentration, and active carbon are 303.0 K, 8.00 bar, 7.00 M, 0.75 g, respectively, and 25.99% for the input variables and desirability index of 0.732. The CO₂ loading, absorption capacity, and absorption percentage are obtained in the range of 0.572–1.180 mol_CO2/mol_TEA, 0.208–0.506 wt%, and 12.73–32.61% in Triethanolamine (TEA) solutions in activated carbon, respectively. All dependent variables had a p value of less than 0.05, indicating that models were significant and substantial. The result showed that the addition of solid particles to chemical solvents effectively enhances CO₂ absorption.

     

Organocopper-based magnetically recoverable and reusable nanocatalyst for efficient synthesis of novel 1,2,3-triazole-based sulfonamides in green medium

Research on Chemical Intermediates - We report robust green synthesis of novel 1,2,3-triazole-based sulfonamides bearing different motifs such as fluorine under click conditions in presence of a...     

Ionic metallo‐Schiff base polymers of VO2+, Zn2+ and Cu2+: Synthesis,characterization and solid‐state conductivity

The viologen‐type dialdehyde of [N,N′‐bis(methylsalicylaldehyde)‐4,4′‐bipyridinium] dichloride (DA) was synthesized by reacting 5‐chloromethylsalicylaldehyde and 4,4′‐bipyridine. Then a new polymeric Schiff base ligand (PSBL) was synthesized by the condensation reaction of ethylenediamine and DA in methanol under reflux conditions. Afterwards, new ionic metallo‐Schiff base polymers (IMSPs) were synthesized by reacting PSBL with VO(acac)₂, ZnCl₂ and CuCl₂ via coordination chelation. DA, PSBL and IMSPs were characterized using various analytical methods and spectral techniques. The solid‐state electrical conductivities of PSBL and IMSPs were studied. The electrical conductivity of these polymers at 300 K ranged from 1.30 × 10^?5 to 4.52 × 10^?10 Ω^?1 m^?1, which means they are potential organic and metallo‐organic semiconductors.     

Dioxidomolybdenum(VI) complexes of allyl N'-2-hydroxy-3-methoxybenzylidenecarbamohydrazonothioate: synthesis,spectral, and theoretical investigations

The new dibasic NNO ligand H₂L (H₂L = allyl N′-2-hydroxy-3-methoxybenzylidenecarbamohydrazonothioate) was synthesized by condensation of 2-hydroxy-3-methoxybenzaldehyde with the product resulting from the reaction of thiosemicarbazide with allyl bromide. Four dioxidomolybdenum(VI) complexes with the general formula [MoO₂L(S)] (S=MeOH, EtOH, DMSO, and 1-methylimidazole) were synthesized and characterized by elemental analysis, FT-IR, EI-MS and UV-Vis spectroscopy, and by X-ray crystallography. Spectroscopic evidence indicates that the cis-MoO₂ chelates have octahedral geometry in which H₂L coordinates via the phenolate oxygen, azomethine nitrogen and deprotonated thioamide nitrogen. The other sites are occupied by two oxido and an additional ligand (S). Density functional theory calculations of spectral parameters were also carried out for these systems.     

Analytical performance of a high-pressure radio frequency-only quadrupole collision cell with an axial field applied by using conical rods

The effect on triple-quadrupole performance of applying an axial field, in an rf-only quadrupole collision cell operated at pressures sufficiently high that collisional focusing is operating, has been investigated. The advantages of such cells have been shown previously to include increased transmission and much improved resolution in fragment ion spectra relative to the performance of collision cells operating at lower gas pressures. The disadvantages of high-pressure collision cells all derive from the relatively long transit times for the ions, which can be long relative to characteristic times for scanning the first mass filter (precursor ion selector) or for switching its setting in multiple reaction monitoring (MRM) cycles. The present work describes experiments on a high-pressure cell in which an axial field is created through use of conical rather than cylindrical or hyperbolic rods. In addition, results of computations of the electric fields within such a cell, and of ion trajectories through it, are presented. It is shown that application of axial fields of the order of 0. 1 V/cm can remove all hysteresis effects associated with the long ion transit times, and thus provide excellent performance in quantitation work using MRM, as well as in other scan modes. Furthermore, the advantages of collisional focusing in quadrupole collision cells are shown to be unimpaired by these low axial fields.     

Synthesis of New β,β′-Diketodithioethers via Swern Oxidation and Study of Their Hydrazone Formation Rate

The synthesis of β,β′-diketodithioethers 4b–j from corresponding β,β′-dihydroxydithioethers 3b–j was carried out by a Swern oxidation using DMSO-oxalyl chloride as oxidizing agent. β,β′-Dihydroxydithioethers 3b–j were prepared by the reaction of two molar equivalents of epoxides 1b–j with dimercaptoethane 2 in the presence of a saturated aqueous solution of potassium carbonate. The reactivity behavior of imine formation of the β,β′-diketodithioethers 4b–j by 2,4-dinitrophenylhydrazine was also investigated, and a mechanism was proposed by using molecular orbital (MO) calculations. To confirm the proposed mechanism, the role of the thia function to activate hydrazone formation by measuring HOMO-LUMO energy levels was also demonstrated.     

Constraints on the universe as a numerical simulation

The level scheme above the proton threshold in ²⁶Si is crucial for evaluating the ²⁵Al(p, γ)²⁶Si stellar reaction, which is important for understanding the astrophysical origin of the long-lived cosmic radioactivity ²⁶Al(T _1/2 = 7.17 × 10⁵ y) in the Galaxy. The excited states in ²⁶Si have been studied using an in-beam γ-ray spectroscopy technique with the ²⁴Mg(³He, nγ)²⁶Si reaction. γ-rays with energies up to 4.6 MeV emitted from excited states in ²⁶Si have been measured using large volume HPGe detectors. The spin-parity of one of the most important states reported recently at 5890.0keV has been assigned as 0⁺ by γ-γ angular correlation measurements in this work.