Acid Gas Converting to Organosulfur and Hydrogen in Methanol Thiolation Using Alkali Promoted Catalysts: Case Study

Catalysis Surveys from Asia - An acid gas stream was utilized instead of pure H2S as feedstock in the methanol thiolation reaction with Alkali/W/γ-Al2O3 catalysts. The catalysts were...     

SSNTD and radiochemical studies on the transmutation of nuclei using relativistic ions

Extended targets were irradiated for transmutation studies with relativistic heavy ions. For this, a metal core was surrounded by a paraffin moderator. The metal is either copper or lead and it was irradiated with deuterium, alpha, or carbon beams of 1.5 or 3.7 GeV/u at the SYNCHROPHASOTRON, LHE, JINR, Dubna, Russia. During this irradiation copious amounts of secondary neutrons are produced and studied with SSNTD detectors and radiochemical sensors, for example ¹³⁹La (n, γ) ¹⁴⁰La→β⁻. The yield of reaction products allows an estimation of secondary neutron fluxes. The yields of all kinds of reactions produced with deuterium and alpha beams obey to some extent the law of “limiting fragmentation”, i.e. they show little influence on the energy and the kind of incoming particles. However, one observes with 44 GeV ¹²C ions always enhanced nuclear cross-sections induced by secondary particles. This behavior could not be confirmed with theoretical estimations based on the Dubna Cascade Model in its Cascade Evaporation Model version (DCM-CEM). Finally, some results for transmutation studies on ¹²⁷I and Cu will be presented.     

Fischer–Tropsch synthesis: evaluation of Gd and Ru promoters effect on Co/<Emphasis Type="Italic">γ</Emphasis>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst at different conditions

In this study, the effect of Ru and Gd promoters on 15Co/\(\gamma\)-Al₂O₃ catalyst in the Fischer–Tropsch synthesis is investigated. The catalysts were synthesized by dry impregnation method and characterized by XRD, adsorption/desorption of nitrogen, TPR, TEM, ICP and XPS analyses. Activity and selectivity of the catalysts were examined in a fixed bed reactor at 210–230 °C with a H₂/CO ratio of 2 and atmospheric pressure. The results showed that the Ru-promoted catalyst has the highest activity and methane selectivity which reduce the chain growth probability. The Gd-promoted catalyst was shown smaller particle size and higher dispersion of cobalt particles in compared with unpromoted catalyst. The smaller particles have more interaction and thus show the lower catalyst reducibility. The presence of Gd in the catalyst cause higher chain growth probability compared to the unpromoted one. The Ru–Gd-promoted catalysts were shown a synergic effect in the catalyst reducibility. Based on the screening of the catalysts in the atmospheric pressure; the unpromoted, 0.1Ru/15Co/Al₂O₃, and 0.1Ru1Gd/15Co/Al₂O₃ catalysts were selected to test at high pressure conditions, which the 0.1Ru1Gd/15Co catalyst showed the highest C₅ ⁺ selectivity (75%) compared with the 0.1Ru/15Co/Al₂O₃ and the unpromoted one.     

Application of 1,4-Diaminoanthraquinone as a New Sensing Material for Fabrication of a Iron(III)-Selective Modified Carbon Paste Electrode

In the present work, a novel sensitive electrochemical potentiometric sensor for sensing Fe³⁺ ions based on 1,4-diaminoanthraquinone (DAQ) as a hydrophobic selector element was prepared to implement as an ion selective carbon paste electrode in the aqueous solutions. The adequate amounts of ionophore (5%), paraffin oil (25%) as a binder, Nanosilica (NS: 0.5%) multi-wall carbon nanotubes (MWCNTs: 1%) as a modifier, and graphite powder (68.5%) as an inert matrix was occupied to form the paste. This new FeCP sensor demonstrated a Nernstian slope of 19.7 ± 0.7 mV per decade over widish linear range between 1.0 × 10^–8 to 1.0 × 10^–2 mol L^–1 at working pH range of 1.9–5.0 in the optimized conditions. The average elapsed time to response of electrode was about ~6 s for concentrations from lower (1.0 × 10^?8 mol L^–1) to higher (1.0 × 10^?2 mol L^–1) of Fe³⁺ ion solution. The selectivity of electrode toward Fe³⁺ ions in comparison with other cations was studied by matched potential method. The making FeCP sensor has been put to use successfully as an indicator electrode in analytical applications such as the potentiometric titration and determination of iron(III) ion in blend of different ions.     

Ionophore Properties of Schiff Base Compounds as Ion Sensing Molecules for Fabricating Cu(II) Ion-Selective Electrodes

Bis(2-hydroxybenzaldehyde)-1,2-diaminoethane (L^I), bis(2-hydroxybenzaldehyde)-1,3-diaminopropane (L^II) and bis(2-hydroxybenzaldehyde)-4,4'-methylendianiline (L^III) were examined as ionophores for fabrication of polyvinylchloride (PVC) membrane Cu(II) ion-selective potentiometric sensors. The optimum composition (%) for the sensors was: 5 L^I, 30 PVC, 6 sodium tetraphenylborate (NaTPB), 59 ortho-nitrophenyloctyl ether (NPOE); 4 L^II, 30 PVC, 5 NaTPB, 61 dibutyl phthalate; 6 L^III, 30 PVC, 5 NaTPB, 59 NPOE. The linear response range of the electrodes was 5 × 10^–4–0.05 (L^I), 5 × 10^–4–0.1 (L^II) and 1 × 10^–6–0.01 M (L^III), and the corresponding detection limits were 4 × 10^–4, 4 × 10^–4 and 2 × 10^–7 M, respectively. The sensors were showed rapid response time (≈10 s). Their responses were independent on pH in the range 2.5–5.0 (L^I), 3.2–4.7 (L^II) and 4.0–5.0 (L^III). The selectivity of the prepared electrodes towards copper ions over some mono-, di- and trivalent metal ions was evaluated. The sensors were used as indicator electrode in potentiometric titration of copper ions in aqueous solutions.