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Al2O3 Catalyst (al2o3 + catalyst)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Characterization and Activity of Cu-MnOx/,-Al2O3 Catalyst for Hydrogenation of Carbon Dioxide

CHINESE JOURNAL OF CHEMISTRY, Issue 5 2001
Gong-Xin Qi
Abstract The effect of manganese on the dispersion, reduction behavior and active states of surface of supported copper oxide catalysts have been investigated by XRD, temperature-programmed reduction and XPS. The activity of methanol synthesis from CO2/H2 was also investigated. The catalytic activity over CuO-MnOx/,-Al2O3 catalyst for CO2 hydrogenation is higher than that of CuO/,-Al2O3. The adding of manganese is beneficial in enhancing the dispersion of the supported copper oxide and make the TPR peak of the CuO-MnKx/,-Al2O3 catalyst different from the individual supported copper and manganese oxide catalysts, which indicates that there exists strong interaction between the copper and manganese oxide. For the CuO/,-Al2O3 catalyst there are two reducible copper oxide species; , and , peaks are attributed to the reduction of highly dispersed copper oxide species and bulk CuO species, respectively. For the CuO-MnOx/,-Al2O3 catalyst, four reduction peaks are observed, , peak is attributed to the dispersed copper oxide species; , peak is ascribed to the bulk CuO; , peak is attributed to the reduction of high dispersed CuO interacting with manganese; , peak may be the reduction of the manganese oxide interacting with copper oxide. XPS results show that Cu+ mostly existed on the working surface of the Cu-Mn/,-Al2O3 catalysts. The activity was promoted by Cu with positive charge which was formed by means of long path exchange function between CuOMn. These results indicate that there is synergistic interaction between the copper and manganese oxide, which is responsible for the high activity of CO2 hydrogenation. [source]

Size-Dependent Catalytic Activity of Supported Palladium Nanoparticles for Aerobic Oxidation of Alcohols

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2008
Jing Chen
Abstract Silica-alumina (SiO2 -Al2O3)-supported palladium catalysts prepared by adsorption of the tetrachloropalladate anion (PdCl42,) followed by calcination and reduction with either hexanol or hydrogen were studied for the aerobic oxidation of alcohols. The mean size of the Pd particles over the SiO2 -Al2O3 support was found to depend on the Si/Al ratio, and a decrease in the Si/Al ratio resulted in a decrease in the mean size of the Pd nanoparticles. By changing the Si/Al ratio, we obtained supported Pd nanoparticles with mean sizes ranging from 2.2 to 10,nm. The interaction between the Pd precursor and the support was proposed to play a key role in tuning the mean size of the Pd nanoparticles. The Pd/SiO2 -Al2O3 catalyst with an appropriate mean size of Pd particles could catalyze the aerobic oxidation of various alcohols to the corresponding carbonyl compounds, and this catalyst was particularly efficient for the solvent-free conversion of benzyl alcohol. The intrinsic turnover frequency per surface Pd atom depended significantly on the mean size of Pd particles and showed a maximum at a medium mean size (3.6,4.3,nm), revealing that the aerobic oxidation of benzyl alcohol catalyzed by the supported Pd nanoparticles was structure-sensitive. [source]

Cyclohexene hydrogenation using Group VIII metal complexes as catalysts in heterogeneous and homogeneous conditions

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2001
E Quiroga
Abstract The stability and catalytic behaviour of a ruthenium complex with chloride and tridecylamine as ligands were studied. The hydrogenation of cyclohexene carried out in mild conditions, both in homogeneous and heterogeneous conditions, was used as a test reaction. FTIR and XPS results show that the active species is the complex itself, which is stable under the reaction conditions. XPS determination shows that the ruthenium complex is tetra-coordinated, suggesting that its formula is [RuCl2(NH2(CH2)12CH3)2]. This ruthenium complex supported on ,-Al2O3 is more active and sulfur-resistant than the same complex unsupported and even more than a nickel complex with the above mentioned ligands. The Ru complex, supported or not, is also more active and sulfur-resistant than a conventional Ru/,-Al2O3 catalyst evaluated in the same operational conditions. © 2001 Society of Chemical Industry [source]

Millisecond catalytic reforming of monoaromatics over noble metals

AICHE JOURNAL, Issue 4 2010
C. M. Balonek
Abstract The millisecond autothermal reforming of benzene, toluene, ethylbenzene, cumene, and styrene were independently studied over five noble metal-based catalysts: Pt, Rh, Rh/,-Al2O3, Rh,Ce, and Rh,Ce/,-Al2O3, as a function of carbon-to-oxygen feed ratio. The Rh,Ce/,-Al2O3 catalyst exhibited the highest feedstock conversion as well as selectivities to both synthesis gas and hydrocarbon products (lowest selectivities to H2O and CO2). Experimental results demonstrate a high stability of aromatic rings within the reactor system. Benzene and toluene seem to react primarily heterogeneously, producing only syngas and combustion products. Ethylbenzene and cumene behaved similarly, with higher conversions than benzene and toluene, and high product selectivity to styrene, likely due to homogeneous reactions involving their alkyl groups. Styrene exhibited low conversions over Rh,Ce/,-Al2O3, emphasizing the stability of styrene in the reactor system. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Light FCC gasoline olefin oligomerization over a magnetic NiSo4/,-Al2o3 catalyst in a magnetically stabilized bed

AICHE JOURNAL, Issue 3 2009
Ying Peng
Abstract Magnetic NiSO4/,-Al2O3 catalysts were prepared by impregnating NiSO4 solutions onto the ,-Al2O3 support containing a magnetic material of Fe3O4. Characterization by XRD, NH3 -TPD, and thermal analysis showed that the magnetic NiSO4/,-Al2O3 catalyst with a nickel content of 7.0% by weight had a monolayer dispersion of NiSO4 and the largest number of moderate strength acid sites, and a high specific saturation magnetization. The magnetic catalyst was evaluated for light FCC gasoline olefin oligomerization in both fixed-bed and magnetically stabilized bed (MSB) reactors. Comparing with that in the fixed-bed reactor, the optimal reaction temperature in the MSB lowered to 443 K, and its space velocity ranged broadly from 2.0 to 6.0 h,1. The sulfur-free diesel distillate produced by operation of the MSB for 100 h had higher cetane number and good low-temperature flow property, which illuminates a promising application of the MSB to manufacture clean diesel fuels with high productivity and flexibility. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Analysis of a perovskite ceramic hollow fibre membrane reactor for the partial oxidation of methane to syngas

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009
Xiaoyao Tan
Abstract A mathematical model of an oxygen permeable dense ceramic hollow membrane reactor packed with a Ni/,-Al2O3 catalyst for the partial oxidation of methane (POM) to syngas has been developed. With the present model, various operating conditions such as temperature, operating pressures and feed concentrations affecting the performance of the reactor were investigated theoretically. The applied membrane area plays the key role in the operation of the membrane reactor. Assuming that the La0.6Sr0.4Co0.2Fe0.8O3,, (LSCF) membrane is stable under the pressures and temperatures operated, the optimum membrane area required for the POM to syngas is predicted to be varied from 98 to 16 cm2 per cm3/s (STP) of methane feed when the operating temperatures are increased from 1148 to 1248 K. In order to run the membrane reactor economically and safely, the pressures in both shell and lumen sides should be kept close to one atmosphere. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Synthesis of N -Alkylhexahydroazepine by One-step Catalytic Alkylation and Hydrogenation of Caprolactam

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2006
Jun-Ming Du
Abstract A new synthetic method for the preparation of N -alkylhexahydroazepine by one-step catalytic alkylation and hydrogenation of caprolactam has been developed. Alkylated caprolactam was firstly synthesized by catalytic alkylation of caprolactam with alcohol and then directly hydrogenated into N -alkylhexahydroazepine over Cu-ZnO/, -Al2O3 catalyst. [source]

Characterization and Activity of Cu-MnOx/,-Al2O3 Catalyst for Hydrogenation of Carbon Dioxide

CHINESE JOURNAL OF CHEMISTRY, Issue 5 2001
Gong-Xin Qi
Abstract The effect of manganese on the dispersion, reduction behavior and active states of surface of supported copper oxide catalysts have been investigated by XRD, temperature-programmed reduction and XPS. The activity of methanol synthesis from CO2/H2 was also investigated. The catalytic activity over CuO-MnOx/,-Al2O3 catalyst for CO2 hydrogenation is higher than that of CuO/,-Al2O3. The adding of manganese is beneficial in enhancing the dispersion of the supported copper oxide and make the TPR peak of the CuO-MnKx/,-Al2O3 catalyst different from the individual supported copper and manganese oxide catalysts, which indicates that there exists strong interaction between the copper and manganese oxide. For the CuO/,-Al2O3 catalyst there are two reducible copper oxide species; , and , peaks are attributed to the reduction of highly dispersed copper oxide species and bulk CuO species, respectively. For the CuO-MnOx/,-Al2O3 catalyst, four reduction peaks are observed, , peak is attributed to the dispersed copper oxide species; , peak is ascribed to the bulk CuO; , peak is attributed to the reduction of high dispersed CuO interacting with manganese; , peak may be the reduction of the manganese oxide interacting with copper oxide. XPS results show that Cu+ mostly existed on the working surface of the Cu-Mn/,-Al2O3 catalysts. The activity was promoted by Cu with positive charge which was formed by means of long path exchange function between CuOMn. These results indicate that there is synergistic interaction between the copper and manganese oxide, which is responsible for the high activity of CO2 hydrogenation. [source]

Light FCC gasoline olefin oligomerization over a magnetic NiSo4/,-Al2o3 catalyst in a magnetically stabilized bed

AICHE JOURNAL, Issue 3 2009
Ying Peng
Abstract Magnetic NiSO4/,-Al2O3 catalysts were prepared by impregnating NiSO4 solutions onto the ,-Al2O3 support containing a magnetic material of Fe3O4. Characterization by XRD, NH3 -TPD, and thermal analysis showed that the magnetic NiSO4/,-Al2O3 catalyst with a nickel content of 7.0% by weight had a monolayer dispersion of NiSO4 and the largest number of moderate strength acid sites, and a high specific saturation magnetization. The magnetic catalyst was evaluated for light FCC gasoline olefin oligomerization in both fixed-bed and magnetically stabilized bed (MSB) reactors. Comparing with that in the fixed-bed reactor, the optimal reaction temperature in the MSB lowered to 443 K, and its space velocity ranged broadly from 2.0 to 6.0 h,1. The sulfur-free diesel distillate produced by operation of the MSB for 100 h had higher cetane number and good low-temperature flow property, which illuminates a promising application of the MSB to manufacture clean diesel fuels with high productivity and flexibility. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Characterization and Activity of Cu-MnOx/,-Al2O3 Catalyst for Hydrogenation of Carbon Dioxide

CHINESE JOURNAL OF CHEMISTRY, Issue 5 2001
Gong-Xin Qi
Abstract The effect of manganese on the dispersion, reduction behavior and active states of surface of supported copper oxide catalysts have been investigated by XRD, temperature-programmed reduction and XPS. The activity of methanol synthesis from CO2/H2 was also investigated. The catalytic activity over CuO-MnOx/,-Al2O3 catalyst for CO2 hydrogenation is higher than that of CuO/,-Al2O3. The adding of manganese is beneficial in enhancing the dispersion of the supported copper oxide and make the TPR peak of the CuO-MnKx/,-Al2O3 catalyst different from the individual supported copper and manganese oxide catalysts, which indicates that there exists strong interaction between the copper and manganese oxide. For the CuO/,-Al2O3 catalyst there are two reducible copper oxide species; , and , peaks are attributed to the reduction of highly dispersed copper oxide species and bulk CuO species, respectively. For the CuO-MnOx/,-Al2O3 catalyst, four reduction peaks are observed, , peak is attributed to the dispersed copper oxide species; , peak is ascribed to the bulk CuO; , peak is attributed to the reduction of high dispersed CuO interacting with manganese; , peak may be the reduction of the manganese oxide interacting with copper oxide. XPS results show that Cu+ mostly existed on the working surface of the Cu-Mn/,-Al2O3 catalysts. The activity was promoted by Cu with positive charge which was formed by means of long path exchange function between CuOMn. These results indicate that there is synergistic interaction between the copper and manganese oxide, which is responsible for the high activity of CO2 hydrogenation. [source]

Light FCC gasoline olefin oligomerization over a magnetic NiSo4/,-Al2o3 catalyst in a magnetically stabilized bed

AICHE JOURNAL, Issue 3 2009
Ying Peng
Abstract Magnetic NiSO4/,-Al2O3 catalysts were prepared by impregnating NiSO4 solutions onto the ,-Al2O3 support containing a magnetic material of Fe3O4. Characterization by XRD, NH3 -TPD, and thermal analysis showed that the magnetic NiSO4/,-Al2O3 catalyst with a nickel content of 7.0% by weight had a monolayer dispersion of NiSO4 and the largest number of moderate strength acid sites, and a high specific saturation magnetization. The magnetic catalyst was evaluated for light FCC gasoline olefin oligomerization in both fixed-bed and magnetically stabilized bed (MSB) reactors. Comparing with that in the fixed-bed reactor, the optimal reaction temperature in the MSB lowered to 443 K, and its space velocity ranged broadly from 2.0 to 6.0 h,1. The sulfur-free diesel distillate produced by operation of the MSB for 100 h had higher cetane number and good low-temperature flow property, which illuminates a promising application of the MSB to manufacture clean diesel fuels with high productivity and flexibility. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]