02702nas a2200337 4500008004100000022001400041245012800055210006900183260007300252300001200325490000700337520156900344653003201913653002601945653001601971653001701987653001402004653001302018653001702031653002302048653001702071653003002088653002002118653000802138100001302146700001502159700001802174700001502192700003002207856012702237 2005 eng d a0926-337300aIn situ XPS investigations of Cu1-xNixZnAl-mixed metal oxide catalysts used in the oxidative steam reforming of bio-ethanol0 aIn situ XPS investigations of Cu1xNixZnAlmixed metal oxide catal aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a287-2990 v553 a

A series of CuNiZnAl-multicomponent mixed metal oxide catalysts with various Cu/Ni ratios were prepared by the thermal decomposition of Cu1-xNixZnAl-hydrotalcite-like precursors and tested for oxidative steam reforming of bio-ethanol. Dehydrogenation of EtOH to CH3CHO is favored by Cu-rich catalyst. Introduction of Ni leads to C-C bond rupture and producing CO, CO2 and CH4. H-2 yield (selectivity) varied between 2.6-3.0 mol/mol of ethanol converted (50-55%) for all catalysts at 300 degreesC. The above catalysts were subjected to in situ XPS studies to understand the nature of active species involved in the catalytic reaction. Core level and valence band XPS as well as Auger electron spectroscopy revealed the existence of Cu2+, Ni2+ and Zn2+ ions on calcined materials. Upon in situ reduction at reactions temperatures, the Cu2+ was fully reduced to Cu-0. while Ni2+ and Zn2+ were partially reduced to Ni-0 and Zn-0, respectively. On reduction, the nature of ZnO on Cu-rich catalyst changes from crystalline to amorphous, relatively inert and highly stabilized electronically. Relative concentration of the Ni-0 and Zn-0 increases upon reduction with decreasing Cu-content. Valence band results demonstrated that the overlap between 3d bands of Cu and Ni was marginal on calcined materials, and no overlap due to metallic clusters formation after reduction. Nonetheless, the density of states at Fermi level increases dramatically for Ni-rich catalysts and likely this influences the product selectivity. (C) 2004 Elsevier B.V. All rights reserved.

10aauger electron spectroscopy10aAutothermal reforming10aBio-ethanol10acopper oxide10afuel cell10aHydrogen10ahydrotalcite10amixed metal oxides10anickel oxide10aoxidative steam reforming10aSteam reforming10aXPS1 aVelu, S.1 aSuzuki, K.1 aVijayaraj, M.1 aBarman, S.1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/situ-xps-investigations-cu1-xnixznal-mixed-metal-oxide-catalysts-used-oxidative-steam-001521nas a2200217 4500008004100000245013400041210006900175260000800244300001100252490000700263520073000270653002001000653002001020653001701040653002801057653001701085653001601102100002301118700003001141856013201171 2021 eng d00aCatalytic applications of hydrotalcite and related materials in multi -component reactions: concepts, challenges and future scope0 aCatalytic applications of hydrotalcite and related materials in  cSEP a1004580 v223 aHydrotalcites (HTs) are the potential substitute to conventional base catalysts. HTs are useful in efficient syntheses of various heterocycles, such as chromenes, pyrans, pyrazoles, triazoles, using multi-component reactions. This review focuses on the chemistry of HTs and particularly hydrotalcites and related materials in the synthesis of heterocycles. The effects of preparation method and, physico-chemical parameters, such as calcination, molar ratio of metals, role of intercalated ions, surface area, on the catalytic activities are discussed. Along with technical aspects, this review also unlocks various untouched areas in developing sustainable catalyst for syntheses of heterocycles, drugs, etc. for the future.10agreen chemistry10agreen synthesis10aheterocycles10aheterogeneous catalysis10ahydrotalcite10aMetal Oxide1 aBurange, Anand, S.1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/catalytic-applications-hydrotalcite-and-related-materials-multi-component-reactions-concepts02491nas a2200253 4500008004100000022001400041245014200055210006900197260000800266300001100274490000800285520163000293653001501923653001201938653001701950653001801967653001101985100002601996700002202022700002102044700002602065700002602091856012002117 2022 eng d a0921-510700aComparative investigation on the catalytic performance of HT/SBA-15 and SBA-15/HT composites for the isomerization of glucose to fructose0 aComparative investigation on the catalytic performance of HTSBA1 cDEC a1160520 v2863 a

Hydrotalcites (HT) have a broad spectrum of applications as prosperous heterogeneous catalysts for diverse chemical transformations. The catalytic activity of HT-based materials can be tailored by introducing siliceous material into the internal or external framework. The surface modification of the HT framework with silica mesostructures leads to the formation of versatile Lewis base, Bronsted base and redox catalytic active sites. This work presents the comparative evaluation of the catalytic performance of HT/SBA-15 and SBA-15/HT composites for the isomerization of glucose to fructose using 1-butanol as a solvent. The composites with different external morphology were prepared by a modified template-assisted hydrothermal method, using different HT to SBA-15 proportions. The textural and morphological characterization results conferred the efficiency of the employed post-synthetic intercalation strategy to achieve the successful formation of HT/SBA-15 and SBA-15/HT composites. With optimal HT loading and surface basicity, the HTS-3 composite demonstrated the highest catalytic performance, resulting in good glucose conversions (54 %) with improved selectivity (>83 %). The observed high reactivity could be mainly attributed to the extensive dispersion of HT particles on the SBA-15 component, which contributes to a significant increase in textural properties and surface basicity. Furthermore, special attention is devoted to addressing such reactivity phenomena as active site selectivity, catalyst multifunctionality and multisite reactivity commonly encountered in mesoporous catalysis.

10acomposites10aglucose10ahydrotalcite10aisomerization10aSBA-151 aManikandan, Marimuthu1 aArjunan, Ayyappan1 aPrabu, Marimuthu1 aRaja, Thirumalaiswamy1 aSangeetha, Palanivelu uhttps://library.ncl.res.in/content/comparative-investigation-catalytic-performance-htsba-15-and-sba-15ht-composites02290nas a2200241 4500008004100000022001400041245012600055210006900181260000800250300001100258490000700269520141500276653002201691653001801713653001701731653004501748653003301793100002501826700002601851700002101877700002101898856012901919 2022 eng d a2212-982000aReduction of carbon dioxide to dimethylformamide using ruthenium doped Mg/Al hydrotalcites under supercritical conditions0 aReduction of carbon dioxide to dimethylformamide using ruthenium cJUL a1020550 v613 a

The utilization of carbon dioxide is one of the developing areas due to its significant contribution to global warming. Reducing carbon dioxide (CO2) to formic acid and its derivatives has gained importance because of its thermodynamic limitations and high industrial demand. In this article, we report the synthesis of dime-thylformamide (DMF) using ruthenium doped Mg/Al calcined hydrotalcite by CO2 hydrogenation in the presence of dimethylamine (DMA). At optimized conditions, complete conversion of dimethylamine was achieved with more than 92% product yield at 170 degrees C and 13 MPa pressure with a reaction time of 6 h. Key catalyst properties were determined using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), CO2-temper-ature programmed desorption (TPD), H-2 temperature-programmed reduction (TPR) and Fourier transform infrared (FTIR). The determination of surface morphology was carried out using field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). At the same time, the chemical composition was verified by energy-dispersive X-ray (EDS). In addition, kinetic modeling is performed using the two site Langmuir-Hinshelwood-Hougen-Watson model. The regressed kinetic parameters gave an appropriate fit with experimental concentration values and activation energy is calculated as 413 kJ/mol K-1.

10aDimethylformamide10aHydrogenation10ahydrotalcite10aLangmuir-Hinshelwood-Hougen-Watson model10aSupercritical carbon dioxide1 aChaudhary, Sagar, D.1 aRahatade, Shardul, S.1 aJoshi, Sunil, S.1 aMali, Nilesh, A. uhttps://library.ncl.res.in/content/reduction-carbon-dioxide-dimethylformamide-using-ruthenium-doped-mgal-hydrotalcites-under01635nas a2200229 4500008004100000022001400041245009500055210006900150260000800219490000700227520086000234653001801094653001201112653001701124653001301141100002801154700002301182700002801205700002101233700003201254856011901286 2025 eng d a1867-388000aSynthesis of glycolic acid from glyoxal by using hydrotalcite catalyst and kinetic studies0 aSynthesis of glycolic acid from glyoxal by using hydrotalcite ca cJUN0 v173 a

In this work, Mg-Al hydrotalcite catalysts with different molar ratios were prepared using the co-precipitation method for the synthesis of glycolic acid (GA) from glyoxal. Various reaction parameters such as catalyst molar ratio, time, temperature, catalyst loading, and catalyst poisoning were studied and optimized for better conversion of glyoxal selectively to glycolic acid. Hydrotalcite catalyst with a 2:1 molar ratio of Mg: Al gives 98% conversion of glyoxal with 96% selectivity of glycolic acid at 100 degrees C temperature, 40% catalyst loading, and water as solvent in 8 h. Different characterization methods were used such as XRD, XPS, SEM-EDX, nitrogen adsorption desorption, and CO2-TPD for hydrotalcite catalyst. A kinetic study was also performed to observe the reaction order and activation energy required for the reaction.

10aGlycolic acid10aGlyoxal10ahydrotalcite10akinetics1 aPandya, Harmitkumar, N.1 aKamble, Paresh, A.1 aVinod, Chathakudath, P.1 aRathod, Virendra1 aKantam, Mannepalli, Lakshmi uhttps://library.ncl.res.in/content/synthesis-glycolic-acid-glyoxal-using-hydrotalcite-catalyst-and-kinetic-studies