Kinetics and equilibrium of the olefin-promoted interconversion of n-butyryl- and isobutyrylcobalt tetracarbonyl. The aldehyde isomer ratio in the cobalt-catalyzed olefin hydroformylation

Mihail S. Borovikov, István Kovács, F. Ungváry, Attila Sisak, László Markó

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Abstract

The interconversion of n-butyrylcobalt tetracarbonyl (1) and isobutyrylcobalt tetracarbonyl (2) is catalyzed by ethene, propene, or 1-heptene. The equilibrium constant, K = [1]/[2], is 1.32 ± 0.03 (25°C), 1.38 ± 0.02 (45°C), 1.44 ± 0.03 (65°C), and 1.50 ± 0.02 (85°C), which gives ΔH = 0.47 ± 0.2 kcal/mol and ΔS = 2.13 ± 0.60 cal/(mol K). The rate of the interconversion is first order with respect to both 1 (or 2) and olefin and is negative second order with respect to carbon monoxide. The rate constants for the conversion of 2 to 1 in the presence of 1-heptene are (8.06 ± 0.15) × 10-10 M s-1 (25°C), (7.85 ± 0.17) × 10-9 M s-1 (35°C), and (6.49 ± 0.20) × 10-8 M s-1 (45°C), which give Ea = 41.2 ± 0.4 kcal/mol. These data suggest that the aldehyde isomer ratio in the commercially important cobalt-catalyzed propene hydroformylatipn is mainly determined by the rate of isomerization of 1 to 2, which depends dramatically on the partial pressure of carbon monoxide and on the temperature. Thus, at low PCO, where the rate of acyl isomerization is fast and comparable with the rate of acyl reduction, the 1.6 n/iso ratio of the butyraldehydes (110°C, PCO = 2.5 bar) reflects closely the equilibrium isomer ratio of the precursor butyrylcobalt tetracarbonyls. On the other hand, at high PCO, where the acyl isomerization is almost completely suppressed, the 4.4 n/iso butyraldehyde isomer ratio (110°C, PCO = 90 bar) is the result of the reduction of an acylcobalt isomer mixture that consists mainly of n-butyrylcobalt tetracarbonyl, the kinetically favored acylcobalt product.

Original languageEnglish
Pages (from-to)1576-1579
Number of pages4
JournalOrganometallics
Volume11
Issue number4
Publication statusPublished - 1992

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Hydroformylation
Alkenes
Cobalt
aldehydes
Aldehydes
Isomers
alkenes
cobalt
isomers
Isomerization
Kinetics
isomerization
kinetics
Carbon Monoxide
carbon monoxide
Equilibrium constants
Partial pressure
Rate constants
partial pressure
products

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

Kinetics and equilibrium of the olefin-promoted interconversion of n-butyryl- and isobutyrylcobalt tetracarbonyl. The aldehyde isomer ratio in the cobalt-catalyzed olefin hydroformylation. / Borovikov, Mihail S.; Kovács, István; Ungváry, F.; Sisak, Attila; Markó, László.

In: Organometallics, Vol. 11, No. 4, 1992, p. 1576-1579.

Research output: Contribution to journalArticle

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title = "Kinetics and equilibrium of the olefin-promoted interconversion of n-butyryl- and isobutyrylcobalt tetracarbonyl. The aldehyde isomer ratio in the cobalt-catalyzed olefin hydroformylation",
abstract = "The interconversion of n-butyrylcobalt tetracarbonyl (1) and isobutyrylcobalt tetracarbonyl (2) is catalyzed by ethene, propene, or 1-heptene. The equilibrium constant, K = [1]/[2], is 1.32 ± 0.03 (25°C), 1.38 ± 0.02 (45°C), 1.44 ± 0.03 (65°C), and 1.50 ± 0.02 (85°C), which gives ΔH = 0.47 ± 0.2 kcal/mol and ΔS = 2.13 ± 0.60 cal/(mol K). The rate of the interconversion is first order with respect to both 1 (or 2) and olefin and is negative second order with respect to carbon monoxide. The rate constants for the conversion of 2 to 1 in the presence of 1-heptene are (8.06 ± 0.15) × 10-10 M s-1 (25°C), (7.85 ± 0.17) × 10-9 M s-1 (35°C), and (6.49 ± 0.20) × 10-8 M s-1 (45°C), which give Ea = 41.2 ± 0.4 kcal/mol. These data suggest that the aldehyde isomer ratio in the commercially important cobalt-catalyzed propene hydroformylatipn is mainly determined by the rate of isomerization of 1 to 2, which depends dramatically on the partial pressure of carbon monoxide and on the temperature. Thus, at low PCO, where the rate of acyl isomerization is fast and comparable with the rate of acyl reduction, the 1.6 n/iso ratio of the butyraldehydes (110°C, PCO = 2.5 bar) reflects closely the equilibrium isomer ratio of the precursor butyrylcobalt tetracarbonyls. On the other hand, at high PCO, where the acyl isomerization is almost completely suppressed, the 4.4 n/iso butyraldehyde isomer ratio (110°C, PCO = 90 bar) is the result of the reduction of an acylcobalt isomer mixture that consists mainly of n-butyrylcobalt tetracarbonyl, the kinetically favored acylcobalt product.",
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T1 - Kinetics and equilibrium of the olefin-promoted interconversion of n-butyryl- and isobutyrylcobalt tetracarbonyl. The aldehyde isomer ratio in the cobalt-catalyzed olefin hydroformylation

AU - Borovikov, Mihail S.

AU - Kovács, István

AU - Ungváry, F.

AU - Sisak, Attila

AU - Markó, László

PY - 1992

Y1 - 1992

N2 - The interconversion of n-butyrylcobalt tetracarbonyl (1) and isobutyrylcobalt tetracarbonyl (2) is catalyzed by ethene, propene, or 1-heptene. The equilibrium constant, K = [1]/[2], is 1.32 ± 0.03 (25°C), 1.38 ± 0.02 (45°C), 1.44 ± 0.03 (65°C), and 1.50 ± 0.02 (85°C), which gives ΔH = 0.47 ± 0.2 kcal/mol and ΔS = 2.13 ± 0.60 cal/(mol K). The rate of the interconversion is first order with respect to both 1 (or 2) and olefin and is negative second order with respect to carbon monoxide. The rate constants for the conversion of 2 to 1 in the presence of 1-heptene are (8.06 ± 0.15) × 10-10 M s-1 (25°C), (7.85 ± 0.17) × 10-9 M s-1 (35°C), and (6.49 ± 0.20) × 10-8 M s-1 (45°C), which give Ea = 41.2 ± 0.4 kcal/mol. These data suggest that the aldehyde isomer ratio in the commercially important cobalt-catalyzed propene hydroformylatipn is mainly determined by the rate of isomerization of 1 to 2, which depends dramatically on the partial pressure of carbon monoxide and on the temperature. Thus, at low PCO, where the rate of acyl isomerization is fast and comparable with the rate of acyl reduction, the 1.6 n/iso ratio of the butyraldehydes (110°C, PCO = 2.5 bar) reflects closely the equilibrium isomer ratio of the precursor butyrylcobalt tetracarbonyls. On the other hand, at high PCO, where the acyl isomerization is almost completely suppressed, the 4.4 n/iso butyraldehyde isomer ratio (110°C, PCO = 90 bar) is the result of the reduction of an acylcobalt isomer mixture that consists mainly of n-butyrylcobalt tetracarbonyl, the kinetically favored acylcobalt product.

AB - The interconversion of n-butyrylcobalt tetracarbonyl (1) and isobutyrylcobalt tetracarbonyl (2) is catalyzed by ethene, propene, or 1-heptene. The equilibrium constant, K = [1]/[2], is 1.32 ± 0.03 (25°C), 1.38 ± 0.02 (45°C), 1.44 ± 0.03 (65°C), and 1.50 ± 0.02 (85°C), which gives ΔH = 0.47 ± 0.2 kcal/mol and ΔS = 2.13 ± 0.60 cal/(mol K). The rate of the interconversion is first order with respect to both 1 (or 2) and olefin and is negative second order with respect to carbon monoxide. The rate constants for the conversion of 2 to 1 in the presence of 1-heptene are (8.06 ± 0.15) × 10-10 M s-1 (25°C), (7.85 ± 0.17) × 10-9 M s-1 (35°C), and (6.49 ± 0.20) × 10-8 M s-1 (45°C), which give Ea = 41.2 ± 0.4 kcal/mol. These data suggest that the aldehyde isomer ratio in the commercially important cobalt-catalyzed propene hydroformylatipn is mainly determined by the rate of isomerization of 1 to 2, which depends dramatically on the partial pressure of carbon monoxide and on the temperature. Thus, at low PCO, where the rate of acyl isomerization is fast and comparable with the rate of acyl reduction, the 1.6 n/iso ratio of the butyraldehydes (110°C, PCO = 2.5 bar) reflects closely the equilibrium isomer ratio of the precursor butyrylcobalt tetracarbonyls. On the other hand, at high PCO, where the acyl isomerization is almost completely suppressed, the 4.4 n/iso butyraldehyde isomer ratio (110°C, PCO = 90 bar) is the result of the reduction of an acylcobalt isomer mixture that consists mainly of n-butyrylcobalt tetracarbonyl, the kinetically favored acylcobalt product.

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