Co methanation activity and xps studies of pd supported on zsm5 and y- zeolites

The catalytic activity of Na, H-Y zeolite samples with a varying Si/Al ratio (2·5 to 20) in the transformation of methanol was determined. The amounts of formed individual aliphatic hydrocarbons as function of reaction time were correlated with the amount of Bronsted and Lewis centres on the catalysts. The effect of coke formation on the over-all course of the reaction has been demonstrated.

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Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19901678 ◽

1990 ◽

Vol 55 (7) ◽

pp. 1678-1685

Author(s):

Vladimír Stuchlý ◽

Karel Klusáček

Keyword(s):

Carbon Monoxide ◽

Reaction Rate ◽

Catalyst Activity ◽

Adsorbed Hydrogen ◽

Reaction Products ◽

Co Methanation ◽

Molar Ratios ◽

Rate Determining Step ◽

Higher Temperature ◽

Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

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Aromatic Transformation in Fluidized Bed Reactors

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20081061 ◽

2008 ◽

Vol 73 (8-9) ◽

pp. 1061-1088

Author(s):

Sule Rabiu ◽

Sulaiman Al-Khattaf

Keyword(s):

Fluidized Bed ◽

The Other ◽

Fluidized Bed Reactors ◽

Y Zeolite ◽

Y Zeolites ◽

Toluene Disproportionation ◽

Xylene Isomerization ◽

Toluene Methylation ◽

Toluene Conversion ◽

Medium Acidity

In this work three important aromatic transformations, namely: toluene disproportionation, toluene methylation and m-xylene isomerization, were investigated in a riser simulator which closely mimics the operation of commercial fluidized bed reactors. The transformations were studied over a ZSM-5 based catalyst with medium acidity of 0.23 mmol/g and a series of Y zeolites of acidities between 0.55 and 0.03 mmol/g. For pure toluene feed, it was observed that conversion over the ZSM-5 based catalyst and the weakly acidic Y zeolite (USY-1) was very low. However, with the highly acidic Y zeolite (H-Y), significant toluene conversion was observed with paring reaction more prominent than disproportionation. On the other hand, when toluene was alkylated with methanol, higher toluene conversions were achieved over both the ZSM-5 based and the weakly acidic USY-1 catalysts as compared to when pure toluene feed was used. In addition, p-xylene/o-xylene (P/O) ratios higher than the equilibrium values were obtained in the reaction product over both catalysts. Finally, for m-xylene isomerization it was found that m-xylene conversion increased initially as the acidity of the catalyst increased up to 0.1 mmol/g beyond which any further increase in acidity resulted in a slight decrease in the m-xylene conversion.

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