Continuous Enantioselective Hydrogenation of Ethyl Pyruvate in “Supercritical” Ethane: Relation between Phase Behavior and Catalytic Performance

Wandeler, Roland; Künzle, Niklaus; Schneider, M.; Mallát, Tamás; Baiker, Alfons

doi:10.1006/jcat.2001.3222

Cited by 62 publications

(42 citation statements)

References 37 publications

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“…[25] Into the cell adjusted to 63 mL volume, cyclohexene 1 was introduced at room temperature, followed by the addition of gaseous H 2 and compressed liquid CO 2 in that order. The stirred mixture was heated up from room temperature to 60 8C and then the molar ratio of 1:H 2 :CO 2 in the cell was approximately 1:1.8:9.1 corresponding to the ratio of the flow rates (see caption of Figure 1).…”

Section: Phase Behavior Measurementsmentioning

confidence: 99%

Palladium Supported on an Acidic Resin: A Unique Bifunctional Catalyst for the Continuous Catalytic Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide

et al. 2008

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1% Palladium-doped acidic resin (Amberlyst 15; styrene-divinylbenzene matrix with sulfonic acid groups) is shown to be a highly active catalyst for the continuous catalytic hydrogenation of C=C bonds in supercritical carbon dioxide (scCO 2 ) without affecting C=O bonds. This 1% Pd/Amberlyst-15 catalyst promotes the industrially important selective formation of 2-ethylhexanal from crotonaldehyde in a "one-pot" pathway involving hydrogenation and aldol condensation with a number of merits. The selectivity behavior of 1% Pd/Amberlyst-15 is strikingly different compared to that of 1% Pd/C and 1% Pd/Al 2 O 3 due to its prominent bifunctional nature based on sulfonic acid groups adjacent to metallic Pd sites.+ " sites are suggested to act as both metal and acid sites promoting the bifunctional catalysis.

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Section: Phase Behavior Measurementsmentioning

confidence: 99%

Palladium Supported on an Acidic Resin: A Unique Bifunctional Catalyst for the Continuous Catalytic Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide

et al. 2008

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“…[151] The authors stress that scC 2 H 6 is superior to conventional toluene solvent due to easy product separation after the reaction as well as giving much higher reaction rates (TOF value 15 s À1 in scC 2 H 6 ; 1.8 s À1 in toluene). The research group at Nottingham performed a continuous catalytic asymmetric hydrogenation of dimethyl itaconate to (R)-dimethyl 2-methylsuccinate in scCO 2 (Scheme 13 b).…”

mentioning

confidence: 99%

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

2011

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Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.

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“…The ee was generally between 60 and 70 %, varying slightly with the temperature, P(H 2 ) and total pressure, possibly because higher ees are favoured in the ethane-rich phase. [32] The good enantioselectivities observed in this system have been attributed to a hydrogen bonded interaction between the N À H of the adsorbed cinchonidine and the two carbonyl groups of the ethyl pyruvate on the basis of reflection absorption infrared spectroscopic studies (Figure 1). [33] …”

Section: Davidmentioning

confidence: 87%

“…[31] More conventional heterogeneous catalysts (cinchonidine-modified Pt on alumina) have been employed for the continuous hydrogenation of ethyl pyruvate using "supercritical" ethane (T c : 328C, P c : 48 bar) as the transport vector. [32] In fact, the system exhibited regions in which it was monophasic and regions where it was biphasic (a liquid phase was present) even well above the critical parameters of pure ethane. At low P(H 2 ) there was a significant rate enhancement on passing from the biphasic to the monoScheme 4.…”

Section: Davidmentioning

confidence: 98%

Asymmetric Catalytic Synthesis of Organic Compounds using Metal Complexes in Supercritical Fluids

Cole‐Hamilton

2006

Adv Synth Catal

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The applications of metal-based catalysts for the asymmetric synthesis of organic compounds in supercritical fluids are reviewed. Much of the work discussed concerns hydrogenation and hydroformylation of alkenes, but dihydoxylation and cyclopropanation reactions of alkenes are discussed as are asymmetric Diels-Alder reactions and aldol condensations. Supercritical fluids remove the need for harmful volatile organic solvents, but their use in separating the products from the catalyst by pressure swings or multiphasic systems is also described.

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Continuous Enantioselective Hydrogenation of Ethyl Pyruvate in “Supercritical” Ethane: Relation between Phase Behavior and Catalytic Performance

Cited by 62 publications

References 37 publications

Palladium Supported on an Acidic Resin: A Unique Bifunctional Catalyst for the Continuous Catalytic Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide

Palladium Supported on an Acidic Resin: A Unique Bifunctional Catalyst for the Continuous Catalytic Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

Asymmetric Catalytic Synthesis of Organic Compounds using Metal Complexes in Supercritical Fluids

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