Temperature-programmed reaction of C sub 4 oxygenates on unpromoted and K-promoted ZnCr oxide in relation to the mechanism of the higher alcohol synthesis

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90008-8· OSTI ID:5536953

Lietti, L; Forzatti, P; Tronconi, E; Pasquon, I ^[1]

---

1. Dipartimento di Chimica Industriale ed Ingegneria Chimica G. Natta del Politecnico, Milano (Italy)

The reaction mechanisms operating in the chain growth to C{sub 3+}primary alcohols and in the formation of ketones, secondary alcohols, methyl esters, ethers, and hydrocarbons during higher alcohol synthesis (HAS) over high-temperature modified methanol catalysts have been investigated by the temperature-programmed surface reaction (TPSR) technique. Experiments with linear and branched C{sub 4} alcohols, aldehydes, and acids over an unpromoted ZnCr oxide sample have indicated a series of major catalyst functions, namely aldol-like condensation (also with oxygen retention reversal), decarboxylation and decarboxylative condensations, hydrogenation-dehydrogenation, dehydration and hydrolysis, along with isomerization and cracking. TPSR experiments with linear C{sub 4} molecules over K-promoted ZnCr oxide have demonstrated the effects of alkali addition on the catalyst functions. The results are supportive of a mechanism of chain growth to C{sub 3+} primary alcohols based on a sequence of aldolic condensations of aldehydes, which do not operate over 2-methyl species. Formation of ketones under TPSR conditions is explained by decarboxylative condensation reactions of aldehydic and carboxylate species, as well as by aldol-like condensation reactions with oxygen retention reversal. Secondary alcohols detected in the products of the synthesis are formed by hydrogenation of ketones. Methyl esters and ethers are produced in the synthesis by alcoholysis of carboxylate and alkoxide species, respectively. Decarboxylation of carboxylate species, along with dehydration, may also play a role in the formation hydrocarbons during HAS.

• OSTI ID: 5536953
• Journal Information: Journal of Catalysis; (USA), Vol. 126:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
ALCOHOLS
SYNTHESIS
CHROMIUM OXIDES
CATALYTIC EFFECTS
ZINC OXIDES
ALDEHYDES
CATALYSIS
CATALYTIC CRACKING
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DEHYDRATION
DEHYDROCYCLIZATION
DEHYDROGENATION
ESTERS
ETHERS
HYDROCARBONS
HYDROGENATION
HYDROLYSIS
ISOMERIZATION
KETONES
METHANOL
ORGANIC ACIDS
POTASSIUM
PROMOTERS
SURFACE PROPERTIES
TEMPERATURE CONTROL
ALKALI METALS
CHALCOGENIDES
CHROMIUM COMPOUNDS
CONTROL
CRACKING
DECOMPOSITION
ELEMENTS
HYDROXY COMPOUNDS
KINETICS
LYSIS
METALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
REACTION KINETICS
SOLVOLYSIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
100200* - Synthetic Fuels- Production- (1990-)