Synthesis of polyacenequinones via crossed aldol condensation in pressurized hot water in the absence of added catalysts

Sawada, Takenori; Nakayama, Shu; Kawai-Nakamura, Akiko; Sue, Kiwamu; Iwamura, Hiizu; Hiaki, Toshihiko

doi:10.1039/b914784p

Cited by 5 publications

(12 citation statements)

References 31 publications

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“…SS-810-C), and had an effective inner volume of 2.1 cm 3 . [5] Prior to its use in experiments, the reactor was loaded with 2 % aqueous hydrogen peroxide and conditioned for 1 h at 370 8C to remove any lubricants/oils that might remain from the manufacture of the Swagelok parts and possible catalytic metal sites on the inner wall, unless otherwise stated. The reactor was cleaned with acetone and dried prior to repeated use of about 10 and 5 times for the reactions carried out at 250 and 400 8C, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The effective pH values at 250 8C were calculated by using the relevant dissociation constants of water, hydrochloric acid, and sodium hydroxide, and the ionic activity coefficients reported in the literature, [24] as described in the previous paper. [5] The results are listed in Table 1.…”

Section: The Effect Of the Ph Of Water On The Rates Of The Reactionmentioning

confidence: 99%

“…[3,4,5] Herein, we report a one-pot cyclotrimerization reaction (Scheme 1) of 1-phenyl-2-propyn-1-one to produce 1,3,5-tribenzoylbenzene in the absence of any added catalyst. It is well known that monosubstituted acetylenes RC CH undergo cyclotrimerization reactions to give substituted benzenes under the action of various transition-metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…[ 5] The results are listed in Table 1. The product yields of 1,3,5-tribenzoylbenzene in 400-molar excess water after 1 min at 250 8C were less than 10 % at pH 3-5, it rose gradually, and reached 48 % at pH 7.2, as shown in Figure 3.…”

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confidence: 99%

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One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Tanaka

Nakamura

Iwado

et al. 2010

Chemistry A European J

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Cyclotrimerization of 1-phenyl-2-propyn-1-one in pressurized hot water gave 1,3,5-tribenzoylbenzene in one pot in 65 % yield after 7 min at 200 °C, or in 74 % yield after 60 min at 150 °C. The reaction did not take place in the absence of water, and added base promoted the reaction at 250 °C, suggesting a mechanism of three-consecutive Michael addition reactions. The reaction rates increased with temperature, but the yield of 1,3,5-tribenzoylbenzene decreased at the expense of formation of acetophenone as a side product at higher temperatures. p-Methyl and p-chloro-substituents on the phenyl ring retarded and enhanced the reaction, respectively. A mechanism involving the enol of benzoylacetaldehyde at a branching point of the pathway leading to 1,3,5-tribenzoylbenzene and acetophenone was suggested.

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Section: Resultsmentioning

confidence: 99%

Section: The Effect Of the Ph Of Water On The Rates Of The Reactionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Tanaka

Nakamura

Iwado

et al. 2010

Chemistry A European J

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“…Among the most widely researched types of reactions are base-catalyzed reactions. Many types of reactions, such as aldol condensation, − the Cannizzaro reaction, Michael addition, benzylic acid rearrangement, and hydrolysis, − have been investigated. Recently, the control of base-catalyzed reactions in sub- and supercritical water using solid catalysts has attracted much attention.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Analysis of a Solid Base-Catalyzed Reaction in Sub- and Supercritical Water Using Aldol Condensation with Mg(OH)₂ as a Model

Akizuki

Nakai

Fujii

et al. 2017

Ind. Eng. Chem. Res.

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The kinetics of aldol condensation between acetone and benzaldehyde catalyzed by Mg(OH)2 in sub- and supercritical water at various temperatures (250–450 °C) and pressures (23–31 MPa) was investigated to elucidate the effects of water properties on solid base catalysis. The kinetics obey the Eley–Rideal (ER) mechanism, in which the reaction occurs between acetone enolate adsorbed on the catalyst and benzaldehyde in the bulk phase. Minimal benzaldehyde is adsorbed on the catalyst because of competitive adsorption with water; thus, benzaldehyde in the bulk phase mainly precipitates. The pressure dependence indicates that the reaction rate is affected by the competitive adsorption of water and acetone, as expected for the ER mechanism, and by changes in the solvent properties of supercritical water. The increase in the activation energy and the decrease in the amount of adsorbed acetone with increasing pressure are plausible effects of the solvent properties.

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Novel Functionality of Organic 6,13-Pentacenequinone as a Photocatalyst for Hydrogen Production under Solar Light

Pandit

Arbuj

Mulik

et al. 2014

Environ. Sci. Technol.

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6,13-Pentacenequinone (PQ), an intermediate for an organic semiconductor pentacene, was synthesized by single step solvent free solid state reaction at room temperature under ambient conditions which is hitherto unattempted. The phase purity has been confirmed by XRD and NMR. Optical study showed the absorption at 390 and 412 nm attributed to the π-π* and n-π* transitions, respectively. Cyclic voltammetry indicates the semiconducting nature of PQ having a band gap of 3 eV. The photoluminescence study revealed emissions at 408 and 432 nm. Considering the good thermal stability and absorption well within visible region, wisely, PQ has been used as a photocatalyst for the hydrogen production under solar light. Surprisingly we observed the utmost hydrogen evolution i.e. 4848 μmol/h/0.1 g (quantum efficiency 6.8%). The repeatability and reusability study confirmed the stability of the photocatalyst. The confirmation of the photocatalytic effect was also confirmed using methylene blue (MB) dye degradation under natural sunlight. The observed rate constant (Kapp) for photocatalytic MB degradation was 1.60 × 10(-2) min(-1). The use of an organic photocatalyst for hydrogen production has been demonstrated for the first time. This novel organic photocatalyst can also be explored for water splitting.

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Synthesis of polyacenequinones via crossed aldol condensation in pressurized hot water in the absence of added catalysts

Cited by 5 publications

References 31 publications

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Kinetic Analysis of a Solid Base-Catalyzed Reaction in Sub- and Supercritical Water Using Aldol Condensation with Mg(OH)₂ as a Model

Novel Functionality of Organic 6,13-Pentacenequinone as a Photocatalyst for Hydrogen Production under Solar Light

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Synthesis of polyacenequinones via crossed aldol condensation in pressurized hot water in the absence of added catalysts

Cited by 5 publications

References 31 publications

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Kinetic Analysis of a Solid Base-Catalyzed Reaction in Sub- and Supercritical Water Using Aldol Condensation with Mg(OH)2 as a Model

Novel Functionality of Organic 6,13-Pentacenequinone as a Photocatalyst for Hydrogen Production under Solar Light

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Kinetic Analysis of a Solid Base-Catalyzed Reaction in Sub- and Supercritical Water Using Aldol Condensation with Mg(OH)₂ as a Model