La2O3 promotional effect to Co3O4/γ-Al2O3 catalyst in the oxidative dehydrogenation of ethylbenzene with CO2 as soft oxidant

Co₃O₄/γ-Al₂O₃ catalysts with variable Co₃O₄ loadings (5–20 wt%) and deposition of 15% Co₃O₄ on La₂O₃/γ-Al₂O₃ were prepared by wet impregnation method. La₂O₃-γ-Al₂O₃ support with variable composition of La₂O₃ (2–6 wt%) were prepared by co-precipitation method. All the catalysts were tested for oxidative dehydrogenation of ethylbenzene with CO₂ as soft oxidant. Among the Co₃O₄/γ-Al₂O₃ catalysts, 15% Co₃O₄/γ-Al₂O₃ has shown good performance and hence this catalyst has been chosen to investigate the effect of La₂O₃ species. CO₂ pulse chemisorption data indicate more amount of CO₂ uptake over 15% Co₃O₄/4%La₂O₃/γ-Al₂O₃ catalyst which clearly indicates that this catalyst exhibits good performance in ethylbenzene dehydrogenation with CO₂ as soft oxidant because of reverse water gas shift reaction. Temperature programmed reduction studies indicate that the Co₃O₄ catalysts follow two step reduction mechanism from Co₃O₄ to CoO and then to Co and La₂O₃ promotional effect is visible through facile reduction of Co₃O₄ species. La₂O₃ doping has a vital influence in getting enhanced ethylbenzene conversion, styrene yield and alleviates catalyst deactivation compared to that of unpromoted Co₃O₄/γ-Al₂O₃ catalyst. TGA studies indicate the presence low amount coke deposition during time-on-stream over 15% Co₃O₄/4%La₂O₃/γ-Al₂O₃ catalyst compared to 15% Co₃O₄/γ-Al₂O₃ catalyst.     

Thermodynamic functions of thorium–cerium mixed oxides

Journal of Thermal Analysis and Calorimetry - Thorium–cerium mixed oxides (Th1?xCex)O2 (x?=?0.25, 0.5, 0.75) were prepared by the citrate gel combustion technique. X-ray...     

Additive-free vapour-phase hydrogenation of benzonitrile over MgO-supported Ni catalysts

Research on Chemical Intermediates - MgO-supported Ni catalysts were selectively catalysed by the hydrogenation of benzonitrile to benzylamine in continuous flow at atmospheric pressure without any...     

A novel UPLC–MS/MS method for simultaneous quantification of trigonelline, 4-hydroxyisoleucine,and diosgenin from Trigonella foenum-graecum extract: Application to pharmacokinetic study in healthy and type 2 diabetic rats

Trigonelline (TR), 4-hydroxyisoleucine (4-HI), and diosgenin (DG) are the main bioactives of the purified standardized extract of the popular plant Trigonella foenum-graecum L. (TFG), and it has been proven effective for the treatment of various diseases. However, to the best of our knowledge, no study has investigated the pharmacokinetic parameters of purified standardized T. foenum-graecum extract in normal and diabetic Wistar rats. The present study has developed and validated a rapid, reliable, and sensitive simultaneous ultra-performance liquid chromatography MS method to estimate these bioactives. The chromatographic separation was achieved using methanol, acetonitrile, and 0.1% formic acid with the ideal gradient flow system on a BEH Shield RP 18 column. A positive electrospray ionization mode was selected to estimate m/z values of TR (138.14 > 94.63), 4-HI (148.19 > 74.08), and DG (415.54 > 271.33). The method was robust and reproducible over the linearity range of 60–5000, 6–5000, and 15–5000 ng/mL for TR, 4-HI, and DG, respectively. Using this novel validated method, we investigated the pharmacokinetic parameters of bioactives using Phoenix WinNonlin version 8.0 (Certera) in normal and diabetic rats. The assay was successfully applied for the estimation of pharmacokinetic parameters using noncompartmental analysis. This investigation shows that the absorption rate increased, whereas distribution and elimination processes slowed down in diabetic rats compared with normal rats.     

Synthesis,docking and ADME prediction of novel 1,2,3-triazole-tethered coumarin derivatives as potential neuroprotective agents

Research on Chemical Intermediates - In an attempt to find potential neuroprotective agents, a series of novel 3-(1-((1-(substituted phenyl)-1H-1,2,3-triazol-4-yl) methoxyimino)...     

Green chemical multicomponent approach for the synthesis of C3-pyranopyrazole-substituted coumarins

An efficient and rapid method was developed for the synthesis of C3-pyranopyrazole-substituted coumarins from one-pot five-component reaction of β-keto ester, hydrazine, O-hydroxy aromatic aldehydes, 6-methyl, 4-hydroxy pyranone and aromatic aldehyde in the presence of tri-ethylamine in solvent-free conditions. The microwave-assisted method reported herein offers advantageous shorter reaction times, higher yields and cleaner reaction compared with conventional heating methods.     

One-pot three-component tandem reaction: Synthesis of aryl/alkyl cyanamides libraries and their further conversion into tetrazole derivatives

We have developed methodology for the synthesis of aryl/alkyl cyanamides from amines in one-pot four steps reaction using cheap, readily available and air stable copper source as catalyst under mild reaction conditions. We have also studied the application of cyanamides. In this connection, we could construct aryl tetrazolamine from cyanamides using click reaction     

Reaction mechanism and kinetic analysis of citrate gel-combustion synthesis of nanocrystalline urania

Journal of Thermal Analysis and Calorimetry - The reaction mechanism and the determination of kinetic parameters of the citrate gel combustion synthesis of nanocrystalline urania (U3O8) are being...