Catalytic synthesis of methanol from CO/H/sub 2/. IV. Effects of carbon dioxide

Journal Article · Thu Apr 01 00:00:00 EST 1982 · J. Catal.; (United States)

OSTI ID:5296482

Klier, K; Chatikavanij, V; Herman, R G; Simmons, G W

The effects of carbon dioxide on the catalytic synthesis of methanol over the copper-zinc oxide catalysts were investigated for CO/sub 2//CO/H/sub 2/ ratios between 0/30/70 and 30/0/70. A maximum synthesis rate was observed at CO/sub 2//CO/H/sub 2/ = 2/28/70. At lower concentrations of CO/sub 2/ the catalyst is deactivated by overreduction and at higher concentrations of CO/sub 2/ the synthesis is retarded by a strong adsorption of this gas. A kinetic model is presented which quantitatively describes the observed patterns in the indicated range of synthesis gas compositions and at temperatures between 225 and 250/sup 0/C. This model is consistent with all physical characteristics of the Cu/ZnO between 225 and 250/sup 0/C. This model is consistent with all physical characteristics of the Cu/ZnO catalysts and corroborates earlier findings that an intermediate oxidation state of the catalyst is its active state. The adsorption enthalpies and entropies for the reactants indicate that carbon dioxide is strongly bound and immobile while carbon monoxide and hydrogen are chemisorbed with intermediate strength and experience a considerable mobility in the adsorbed layer. At concentrations of CO/sub 2/ greater than 10%, methane is a side product. Mechanistic implications of this finding are that there is a nonselective pathway parallel to the CO hydrogenation: this pathway may involve formate and methoxy intermediates. 3 figures, 5 tables.

• Research Organization: Lehigh Univ., Bethlehem, PA
• DOE Contract Number: AC02-80CS83001; FG22-80PC30265
• OSTI ID: 5296482
• Journal Information: J. Catal.; (United States), Vol. 74:2
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON MONOXIDE
CHEMICAL REACTIONS
COPPER
CATALYTIC EFFECTS
HYDROGEN
METHANOL
SYNTHESIS
ZINC OXIDES
ADSORPTION
CARBON DIOXIDE
CATALYSTS
CHEMICAL REACTION KINETICS
ENTHALPY
ENTROPY
EXPERIMENTAL DATA
HIGH TEMPERATURE
MATHEMATICAL MODELS
MIXTURES
QUANTITY RATIO
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
ALCOHOLS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DATA
DISPERSIONS
ELEMENTS
HYDROXY COMPOUNDS
INFORMATION
KINETICS
METALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION KINETICS
SORPTION
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
ZINC COMPOUNDS
090121* - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989)
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400201 - Chemical & Physicochemical Properties