Catalytic Syntheses of Ketones

Komarewsky, V. I.; Coley, J. R.

doi:10.1016/s0360-0564(08)60540-4

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…A number of articles on the ketonization of carboxylic acids are available: several oxides, such as Cr 2 O 3 [9,10], Al 2 O 3 [11,12], PbO 2 [12], TiO 2 [13][14][15][16], ZrO 2 [14,[17][18][19], CeO 2 [19][20][21][22][23][24], iron oxide [14,15,[25][26][27], and manganese oxide [12,19,20,22,28], as well as Mg/Al hydrotalcites [29] catalyze the ketonization of carboxylic acids. Many other catalysts have been found since the 19th century: BaCO 3 , MgO, ThO 2 , UO 2 , CdO, ZnO, NiO, Bi 2 O 3 , and SnO 2 have been introduced in references [12,30].…”

Section: Introductionmentioning

confidence: 99%

Ketonization of carboxylic acids over CeO2-based composite oxides

Nagashima

Sato

Takahashi

et al. 2005

Journal of Molecular Catalysis A: Chemical

154

138

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Section: Introductionmentioning

confidence: 99%

Ketonization of carboxylic acids over CeO2-based composite oxides

Nagashima

Sato

Takahashi

et al. 2005

Journal of Molecular Catalysis A: Chemical

154

138

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“…The formation of a carboxylic acid (derivative) during ketonization by disproportionation, that is, by Cannizzaro or Tishchenko reactions, has been discussed (Scheme ) previously. There, the alcohol could be dehydrogenated to form one of the two aldehydes and to produce the H 2 indicated in Equation (3).…”

Section: Resultsmentioning

confidence: 99%

“…However, the mechanism is still under debate: disproportionations of the Cannizzaro or Tishchenko types may provide the acid (derivative) for subsequent ketonic decarboxylation . Alternatively, aldol condensation products have been discussed as intermediates, which are then dehydrogenated and decarboxylated . Furthermore, this reaction is not restricted to aldehydes as starting materials, and primary alcohols can also be converted to symmetrical ketones .…”

Section: Introductionmentioning

confidence: 99%

Carbon–Carbon Bond Formation and Hydrogen Production in the Ketonization of Aldehydes

2016

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Aldehydes possess relatively high chemical energy, which is the driving force for disproportionation reactions such as Cannizzaro and Tishchenko reactions. Generally, this energy is wasted if aldehydes are transformed into carboxylic acids with a sacrificial oxidant. Here, we describe a cascade reaction in which the surplus energy of the transformation is liberated as molecular hydrogen for the oxidation of heptanal to heptanoic acid by water, and the carboxylic acid is transformed into potentially industrially relevant symmetrical ketones by ketonic decarboxylation. The cascade reaction is catalyzed by monoclinic zirconium oxide (m-ZrO2 ). The reaction mechanism has been studied through cross-coupling experiments between different aldehydes and acids, and the final symmetrical ketones are formed by a reaction pathway that involves the previously formed carboxylic acids. Isotopic studies indicate that the carboxylic acid can be formed by a hydride shift from the adsorbed aldehyde on the metal oxide surface in the absence of noble metals.

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“…Alternative mechanisms proposed in the literature for the reaction of aldehydes to the ketone involve the aldol condensation product or adduct as an intermediate. [25][26][27][28][29][30] If this was the case, the final ketone has to be formed at least as fast from the aldol condensation product as from the aldehyde, and with the same or in better yield. However, when the aldol condensation product is passed over CeO2 under similar reaction conditions, in presence or absence of water, the ketone is obtained only in 5% yield versus 57-79% yield when starting directly with the aldehyde ( Table 2, entry 8).…”

Section: Confirmation Of the Carboxylic Acid As Reaction Intermediatementioning

confidence: 99%