ABSTRACT SBA-15 supported Mg–Al hydrotalcite (Mg/Al = 2) composite materials with varied hydrotal... more ABSTRACT SBA-15 supported Mg–Al hydrotalcite (Mg/Al = 2) composite materials with varied hydrotalcite loadings were prepared by precipitation–deposition method. These materials showed promising activity towards CO2 adsorption capacity. The reproducibility studies showed that the material is efficient even after 5 cycles with >96% desorption ability. Analysis of kinetics for CO2 adsorption experiments showed that the regressed plots demonstrate excellent fits to the experimental data. The structural, textural and morphological characteristics of the materials have been determined by XRD, N2 adsorption, FTIR, SEM and TEM techniques.
Co-SBA-15 catalysts were synthesized by direct synthesis and post-synthetic impregnation methods ... more Co-SBA-15 catalysts were synthesized by direct synthesis and post-synthetic impregnation methods at two different loadings of Co viz., 1.2 and 2 wt%. The structure of SBA-15 was found to remain intact even after the incorporation of Co in either of the two methods of catalyst preparation, which was confirmed by low-angle XRD. The existence of Co2+ species were confirmed by characteristic absorption bands of Co in the UV–vis spectra and XPS results. The encapsulation of Co in SBA-15 was found to be highly advantageous in yielding significant amounts of the desired products viz., cyclohexanone and cyclohexanol in the oxidation of cyclohexane in liquid phase without using any solvent under moderate pressure of O2 at 433 K. The catalysts showed high turn over numbers towards the oxidation of cyclohexane to cyclohexanone and 2%CoSYN (2 wt% Co-SBA-15) catalyst showed a maximum of 9.4% conversion of cyclohexane and 78% selectivity towards the formation of cyclohexanone.
SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surfa... more SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surface area, pore size distribution, and X-ray diffraction. The finished catalysts in oxide state were characterized by surface area analysis and X-ray diffraction in the region where the molybdenum oxide lines are seen. The sulfided catalysts were examined by oxygen chemisorption at low temperatures. The catalytic functionalities of these catalysts viz hydrodesulfurization (HDS) and hydrogenation were evaluated on sulfided catalysts. The catalytic activities of these catalysts are compared with γ-Al2O3- and SiO2-supported catalysts. An attempt is made to understand the relationship between oxygen chemisorption and catalytic activities with the help of other characterization results.
ABSTRACT A series of Cu/ (MgO-Al 2 O 3) hydrotalcite catalysts have been prepared by impregnation... more ABSTRACT A series of Cu/ (MgO-Al 2 O 3) hydrotalcite catalysts have been prepared by impregnation technique with a Cu loading ranging between 5 to 25wt%. The prepared catalysts have been characterized by BET technique, X-Ray diffrac-tion, temperature programmed reduction (TPR) and N 2 O pulse chemisorption techniques. Cyclohexanol dehydrogenation and nitrobenzene hydrogenation (individual reactions) and coupling of these two reactions have been performed over these catalysts in vapor phase at atmospheric pressure and at 548K. XRD results reveal the intactness of hydrotalcite structure in reduced and used catalysts with Cu loadings below 15wt%. The beauty of the coupling reaction is to yield cy-clohexanone and aniline from cyclohexanol and nitrobenzene respectively with stoichiometric quantity of H 2 usage for ni-trobenzene hydrogenation. The catalyst with 10wt% Cu loading showed higher activity in the coupling reaction which could be attributed to the better Cu dispersion, smaller Cu particle size and relatively more number of Cu active species presented on the surface of the catalyst.
ABSTRACT Various Ni catalysts with 30 wt% Ni content were prepared by a conventional wet impregna... more ABSTRACT Various Ni catalysts with 30 wt% Ni content were prepared by a conventional wet impregnation method using different supports such as Al2O3, SiO2, ZnO, ZrO2, TiO2 and MgO. The prepared catalysts have been characterised by XRD, N2 physisorption, H2 pulse chemisorption, pyridine adsorbed FTIR, ammonia-TPD, TPR, XPS and TEM techniques. Pyridine adsorbed IR patterns reveal the presence of both Lewis as well as Bronsted acid sites which are responsible for the dehydration of the intermediate 4-hydroxy valeric acid to yield [gamma]-valerolactone. Ammonia-TPD profiles also showed the presence of acidic sites in all catalytic systems, which explains the formation of the targeted product. The better activity shown by the 30 wt% Ni/SiO2 catalyst (signifying maximum productivity, i.e., 0.8506 kgGVL kgcatalyst-1 h-1 at 250 [degree]C) is due to the presence of a greater number of surface Ni species. The present work aims to provide a continuous down flow process for the hydrocyclization of one of the biomass derived platform molecules such as levulinic acid over non-noble metal (nickel) based catalysts. The Ni/SiO2 catalyst is tested for 25 h and found to be stable during the time on stream which reveals its robustness.
SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surfa... more SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surface area, pore size distribution, and X-ray diffraction. The finished catalysts in oxide state were characterized by surface area analysis and X-ray diffraction in the region where the ...
... K. Hari Prasad Reddy a , N. Anand a , PS Sai Prasad a , KS Rama Rao low asterisk , a , E-mail... more ... K. Hari Prasad Reddy a , N. Anand a , PS Sai Prasad a , KS Rama Rao low asterisk , a , E-mail The Corresponding Author and B. David Raju low asterisk , a , E-mail The Corresponding Author. a I & PC Division, Indian Institute of Chemical Technology, Hyderabad 500607, India. ...
Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of alum... more Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of aluminum nitrate and phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate) with NH 3 and precipitation of aluminum nitrate with NH 3 followed by ...
ABSTRACT SBA-15 supported Mg–Al hydrotalcite (Mg/Al = 2) composite materials with varied hydrotal... more ABSTRACT SBA-15 supported Mg–Al hydrotalcite (Mg/Al = 2) composite materials with varied hydrotalcite loadings were prepared by precipitation–deposition method. These materials showed promising activity towards CO2 adsorption capacity. The reproducibility studies showed that the material is efficient even after 5 cycles with >96% desorption ability. Analysis of kinetics for CO2 adsorption experiments showed that the regressed plots demonstrate excellent fits to the experimental data. The structural, textural and morphological characteristics of the materials have been determined by XRD, N2 adsorption, FTIR, SEM and TEM techniques.
Co-SBA-15 catalysts were synthesized by direct synthesis and post-synthetic impregnation methods ... more Co-SBA-15 catalysts were synthesized by direct synthesis and post-synthetic impregnation methods at two different loadings of Co viz., 1.2 and 2 wt%. The structure of SBA-15 was found to remain intact even after the incorporation of Co in either of the two methods of catalyst preparation, which was confirmed by low-angle XRD. The existence of Co2+ species were confirmed by characteristic absorption bands of Co in the UV–vis spectra and XPS results. The encapsulation of Co in SBA-15 was found to be highly advantageous in yielding significant amounts of the desired products viz., cyclohexanone and cyclohexanol in the oxidation of cyclohexane in liquid phase without using any solvent under moderate pressure of O2 at 433 K. The catalysts showed high turn over numbers towards the oxidation of cyclohexane to cyclohexanone and 2%CoSYN (2 wt% Co-SBA-15) catalyst showed a maximum of 9.4% conversion of cyclohexane and 78% selectivity towards the formation of cyclohexanone.
SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surfa... more SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surface area, pore size distribution, and X-ray diffraction. The finished catalysts in oxide state were characterized by surface area analysis and X-ray diffraction in the region where the molybdenum oxide lines are seen. The sulfided catalysts were examined by oxygen chemisorption at low temperatures. The catalytic functionalities of these catalysts viz hydrodesulfurization (HDS) and hydrogenation were evaluated on sulfided catalysts. The catalytic activities of these catalysts are compared with γ-Al2O3- and SiO2-supported catalysts. An attempt is made to understand the relationship between oxygen chemisorption and catalytic activities with the help of other characterization results.
ABSTRACT A series of Cu/ (MgO-Al 2 O 3) hydrotalcite catalysts have been prepared by impregnation... more ABSTRACT A series of Cu/ (MgO-Al 2 O 3) hydrotalcite catalysts have been prepared by impregnation technique with a Cu loading ranging between 5 to 25wt%. The prepared catalysts have been characterized by BET technique, X-Ray diffrac-tion, temperature programmed reduction (TPR) and N 2 O pulse chemisorption techniques. Cyclohexanol dehydrogenation and nitrobenzene hydrogenation (individual reactions) and coupling of these two reactions have been performed over these catalysts in vapor phase at atmospheric pressure and at 548K. XRD results reveal the intactness of hydrotalcite structure in reduced and used catalysts with Cu loadings below 15wt%. The beauty of the coupling reaction is to yield cy-clohexanone and aniline from cyclohexanol and nitrobenzene respectively with stoichiometric quantity of H 2 usage for ni-trobenzene hydrogenation. The catalyst with 10wt% Cu loading showed higher activity in the coupling reaction which could be attributed to the better Cu dispersion, smaller Cu particle size and relatively more number of Cu active species presented on the surface of the catalyst.
ABSTRACT Various Ni catalysts with 30 wt% Ni content were prepared by a conventional wet impregna... more ABSTRACT Various Ni catalysts with 30 wt% Ni content were prepared by a conventional wet impregnation method using different supports such as Al2O3, SiO2, ZnO, ZrO2, TiO2 and MgO. The prepared catalysts have been characterised by XRD, N2 physisorption, H2 pulse chemisorption, pyridine adsorbed FTIR, ammonia-TPD, TPR, XPS and TEM techniques. Pyridine adsorbed IR patterns reveal the presence of both Lewis as well as Bronsted acid sites which are responsible for the dehydration of the intermediate 4-hydroxy valeric acid to yield [gamma]-valerolactone. Ammonia-TPD profiles also showed the presence of acidic sites in all catalytic systems, which explains the formation of the targeted product. The better activity shown by the 30 wt% Ni/SiO2 catalyst (signifying maximum productivity, i.e., 0.8506 kgGVL kgcatalyst-1 h-1 at 250 [degree]C) is due to the presence of a greater number of surface Ni species. The present work aims to provide a continuous down flow process for the hydrocyclization of one of the biomass derived platform molecules such as levulinic acid over non-noble metal (nickel) based catalysts. The Ni/SiO2 catalyst is tested for 25 h and found to be stable during the time on stream which reveals its robustness.
SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surfa... more SBA-15 supported Mo, CoMo, NiMo catalysts were prepared. The supports were characterized by surface area, pore size distribution, and X-ray diffraction. The finished catalysts in oxide state were characterized by surface area analysis and X-ray diffraction in the region where the ...
... K. Hari Prasad Reddy a , N. Anand a , PS Sai Prasad a , KS Rama Rao low asterisk , a , E-mail... more ... K. Hari Prasad Reddy a , N. Anand a , PS Sai Prasad a , KS Rama Rao low asterisk , a , E-mail The Corresponding Author and B. David Raju low asterisk , a , E-mail The Corresponding Author. a I & PC Division, Indian Institute of Chemical Technology, Hyderabad 500607, India. ...
Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of alum... more Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of aluminum nitrate and phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate) with NH 3 and precipitation of aluminum nitrate with NH 3 followed by ...
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