Selective hydrogenation of cinnamaldehyde using ruthenium–phosphine complex catalysts with multiphase reaction systems in and under pressurized carbon dioxide: Significance of pressurization and interfaces for the control of selectivity

Fujita, Shin‐ichiro; Akihara, Shuji; Zhao, Fengyu; Liu, Ruixia; Hasegawa, Masashi; Arai, Masahiko

doi:10.1016/j.jcat.2005.09.024

Cited by 36 publications

(17 citation statements)

References 27 publications

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“…As a result, the former is selectively hydrogenated, yielding COL; the COL formed remains its amphiphilic nature and its C=C bond is difficult to hydrogenate at the water -organic liquid interface. Another possible factor is the effect of CO 2 molecules on the reactivity of the carbonyl group of CAL; under high pressure conditions, CO 2 may selectively increase the reactivity of the C=O bond, compared with the C=C bond, of CAL molecules in the CAL liquid phase or in the dense CO 2 gas phase, as confirmed by high-pressure FTIR measurements [16][17][18].…”

Section: Activity Of Used Catalyst For Aqueous Homogeneous Hydrogenationmentioning

confidence: 98%

“…A 10 cm 3 high-pressure sapphire-windowed view cell was used to determine the existing phases and the volume of these phases under the same conditions as used for hydrogenation reactions [17,18].…”

Section: Phase Behaviormentioning

confidence: 99%

“…Such a selective hydrogenation is one of important reactions for the production of perfume and fine chemicals [5][6][7]. The selectivity for the corresponding unsaturated alcohol, cinnamyl alcohol (COL), can be improved by multiphase reactions using water -organic liquid systems [8][9][10][11][12][13][14][15][16][17][18], water -dense CO 2 systems [19], and supported liquid phase catalysts [20,21]. The present authors have recently indicated that COL is selectively produced with a water-soluble complex of ruthenium -TPPTS (trisodium tris(m-sulfonatophenyl)phosphine), which exists in an aqueous phase being in contact with a bulk CAL phase in toluene, pure CAL, or dense CO 2 ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Fujita

Akihara

Arai

2006

Journal of Molecular Catalysis A: Chemical

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The recyclability of water-soluble ruthenium -phosphine complex catalysts was investigated in water -toluene and in water -pressurized carbon dioxide systems for selective hydrogenation of trans-cinnamaldehyde (CAL). For the first hydrogenation run, the selectivity for cinnamyl alcohol (COL) is high for both toluene and dense CO 2 , because of interfacial catalysis in which the reaction mainly occurs at the interface between the aqueous phase and the other toluene or dense CO 2 phase. The total CAL conversion and the COL selectivity decrease on the second run, more significantly with dense CO 2 than toluene. On the subsequent runs, however, less significant changes were observed. During the first run, the active metal complexes should change to much less active ones such as Ru(H) 2 L n (TPPTS) m (L=COL) by accumulation of the main product of COL. This structural change may occur more easily in multiphase hydrogenation with dense CO 2 than that with toluene, probably because the solubility in the dense CO 2 gas phase is even smaller than that in toluene. For homogeneous reaction of COL in aqueous phase, Ru(H) 2 L n (TPPTS) m catalyzes the isomerization to HCAL compared with the hydrogenation to hydrocinnamyl alcohol. With those complexes, however, the selectivity for COL is still comparable to that for HCAL for multiphase hydrogenation reactions because the hydrogenation of an ampholytic substrate of CAL occurs mainly at interface between water and toluene or dense CO 2 gas phase. Interactions of CO 2 molecules with CAL would also increase the reactivity of carbonyl group of the substrate.

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Section: Activity Of Used Catalyst For Aqueous Homogeneous Hydrogenationmentioning

confidence: 98%

Section: Phase Behaviormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Fujita

Akihara

Arai

2006

Journal of Molecular Catalysis A: Chemical

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“…Furthermore, scCO 2 can show interesting effects on reaction rates and product selectivity [19][20][21][22][23][24][25]. Recently the present authors studied the hydrogenation of NB in scCO 2 over noble metal catalysts including Pd, Pt, Ru, and Rh supported on carbon, silica, and alumina.…”

Section: Introductionmentioning

confidence: 98%

Selective hydrogenation of nitrobenzene to aniline in dense phase carbon dioxide over Ni/γ-Al2O3: Significance of molecular interactions

Meng

Cheng

Akiyama

et al. 2009

Journal of Catalysis

142

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The selective hydrogenation of nitrobenzene (NB) over Ni/γ-Al 2 O 3 catalysts was investigated using different media of dense phase CO 2 , ethanol, and n-hexane. In dense phase CO 2 , the total rate of NB hydrogenation was larger than that in organic solvents under similar reaction conditions; the selectivity to the desired product, aniline, was almost 100% over the whole conversion range of 0-100%. The phase behavior of the reactant mixture in/under dense phase CO 2 was examined at reaction conditions. In situ high-pressure Fourier transform infrared measurements were made to study the molecular interactions of CO 2 with the following reactant and reaction intermediates: NB, nitrosobenzene (NSB), and N-phenylhydroxylamine (PHA). Dense phase CO 2 strongly interacts with NB, NSB, and PHA, modifying the reactivity of each species and contributing to positive effects on the reaction rate and the selectivity to aniline. A possible reaction pathway for the hydrogenation of NB in/under dense phase CO 2 over Ni/γ-Al 2 O 3 is also proposed.

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“…This will facilitate the dissolution of other co-existing gases such as O2, H2, and CO and this may accelerate the reactions involved with these gaseous reactant 3d, 17 To examine the chemical reactions in the presence of CO2, the phase behavior study is important to check whether the reaction is occurring in a single phase homogeneously or heterogeneously in two or more phases. 18 A 10 cm 3 high pressure sapphire window view cell was used for phase behavior study. The observation was made with a similar volumetric ratio of solvent n-hexane to the reactor as used in the hydrogenation reactions.…”

Section: Phase Behavior Observationmentioning

confidence: 99%

Selective hydrogenation of benzyl cyanide to 2-phenylethylamine over a Pd/Al₂O₃ catalyst promoted by synergistic effects of CO₂ and water

et al. 2015

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The selective hydrogenation of benzyl cyanide (BC) to the primary amine of 2-phenylethylamine (PEA) was investigated with a Pd/Al2O3 catalyst in different multiphase reaction media including n-hexane, water, and/or CO2. In neat n-hexane, the hydrogenation of BC occurs at a large rate but no PEA was formed and the secondary amine of N,N-bis(2-phenylethyl)amine (BPEA) was produced as the main product. The pressurization of n-hexane with CO2 decreased the rate of hydrogenation and the main product was BPEA. In this n-hexane -CO2 medium, the catalyst lost its activity during the reaction. When a similar volume of water was added to n-hexane, the rate of hydrogenation did not change so much but a small amount of the primary amine was detected to form in addition to the main product of BPEA. In contrast to these reaction media, a high PEA selectivity of > 90% was obtained and no catalyst deactivation occurred in an n-hexane -water -CO2 medium. The rate of hydrogenation was smaller than that in neat n-hexane but comparable to those in n-hexane -water and n-hexane -CO2 media. Those results show that synergistic effects appears on the selective hydrogenation of BC to PEA when both water and CO2 are included in the reaction medium. Possible roles and actions of water and CO2 have been discussed on the basis of the results of hydrogenation runs under different conditions and in situ ambient and high pressure Fourier transform infrared spectroscopy measurements that give light to molecular interactions of CO2 with reacting species.

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Selective hydrogenation of cinnamaldehyde using ruthenium–phosphine complex catalysts with multiphase reaction systems in and under pressurized carbon dioxide: Significance of pressurization and interfaces for the control of selectivity

Cited by 36 publications

References 27 publications

Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Selective hydrogenation of nitrobenzene to aniline in dense phase carbon dioxide over Ni/γ-Al2O3: Significance of molecular interactions

Selective hydrogenation of benzyl cyanide to 2-phenylethylamine over a Pd/Al₂O₃ catalyst promoted by synergistic effects of CO₂ and water

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Selective hydrogenation of cinnamaldehyde using ruthenium–phosphine complex catalysts with multiphase reaction systems in and under pressurized carbon dioxide: Significance of pressurization and interfaces for the control of selectivity

Cited by 36 publications

References 27 publications

Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Recyclability of water-soluble ruthenium–phosphine complex catalysts in multiphase selective hydrogenation of cinnamaldehyde using toluene and pressurized carbon dioxide

Selective hydrogenation of nitrobenzene to aniline in dense phase carbon dioxide over Ni/γ-Al2O3: Significance of molecular interactions

Selective hydrogenation of benzyl cyanide to 2-phenylethylamine over a Pd/Al2O3 catalyst promoted by synergistic effects of CO2 and water

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Selective hydrogenation of benzyl cyanide to 2-phenylethylamine over a Pd/Al₂O₃ catalyst promoted by synergistic effects of CO₂ and water