Activity for base-catalyzed reactions and characterization of alumina-supported KF catalysts

Kabashima, Hajime; Tsuji, Hideto; Nakata, Shinichi; Tanaka, Yoshinori; Hattori, Hideshi

doi:10.1016/s0926-860x(99)00370-1

Cited by 63 publications

(44 citation statements)

References 23 publications

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“…As shown in table 3, the conversion to methyl esters increased from 42 to 87% with increasing calcination temperature from 378 to 873 K and reached its maximum value (87%) at around a calcination temperature of 873 K. This results show that high-temperature calcination is essential for obtaining the high catalytic activity. However, the conversion gradually decreased as the calcination temperature increased beyond 873 K. A similar dependence of the catalytic activity of KF/Al 2 O 3 on calcination temperature was also observed in the previous literature [14]. The basicity of KF/ZnO samples calcined at different temperatures was examined and is also shown in table 3.…”

Section: Influence Of Calcination Temperaturesupporting

confidence: 82%

“…It has been reported that KF-loaded alumina (KF/ Al 2 O 3 ) shows an efficient solid base catalyst for promoting versatile chemical transformations, such as the Micheal addition, N-, O-and S-alkylation reactions, the Knoevenagel condensation, aldol condensation, Witting-Horner reactions and alkene isomerization [13][14][15][16][17][18][19]. To the best of our knowledge, there is no open literature concerning the solid base of ZnO loaded with KF (KF/ ZnO).…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Biodiesel from Soybean Oil using Heterogeneous KF/ZnO Catalyst

2006

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Biodiesel was produced by transesterification of soybean oil with methanol using ZnO loaded with KF as a solid base catalyst. It was found that the catalyst with 15 wt.% KF loading and calcined at 873 K showed the optimum activity. XRD, IR and Hammett indicator method were employed for the catalyst characterization. The results showed the activity of the catalysts was correlated with their basicity. The influence of various reaction variables on the conversion was also discussed.

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Section: Influence Of Calcination Temperaturesupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Synthesis of Biodiesel from Soybean Oil using Heterogeneous KF/ZnO Catalyst

2006

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“…Benzaldehyde undergoes the Tishenko reaction over CaO 423 K 67) . More recently, we reported that KF/Al2O3 is active for the Tishchenko reaction of benzaldehyde and pivalaldehyde at 323 K 37) . In order to elucidate the activityand selectivity-determining factors, we studied mixed Tishchenko reactions in which two types of aldehyde were allowed to react at 353 K over a series of solid base catalysts 68) .…”

Section: Tishchenko Reactionmentioning

confidence: 99%

“…19 F NMR gives information about the basic sites on KF/Al2O3 which is frequently used for base-catalyzed organic synthesis. Several F containing species were observed at different chemical shifts of −123, −132, −157 and −166 ppm 37) . These four peaks are ascribed to KF associated with water, KF, K3AlF6, and AlF3, respectively.…”

Section: Characterization Of Basic Sitesmentioning

confidence: 99%

Solid Base Catalysts: Generation, Characterization, and Catalytic Behavior of Basic Sites

英¹

2004

J. Jpn. Petrol. Inst.

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Studies of solid base catalysis performed in our group are summarized. Strongly basic sites for most solid base catalysts are generated by removal of water and carbon dioxide by pretreatment at high temperatures from the surfaces. The nature of the surface basic sites varies with the severity of the pretreatment conditions. Rearrangement of surface and bulk atoms occurs, in addition to the removal of water and carbon dioxide, during the pretreatment. The optimum pretreatment temperature varies with the type of reaction. Characterization of basic sites by the indicator method, TPD of CO2, O exchange between adsorbed CO2 and MgO surface, NMR of 133 Cs and 19 F are described. The catalytic behaviors of solid base catalysts are described for the following reactions; (1) double bond migration, (2) hydrogenation, (3) amination, (4) aldol addition, (5) nitroaldol reaction, (6) Michael addition, (7) conjugate addition of alcohol, (8) cyanoethylation, (9) transesterification of ethyl acetate and alcoholysis of propylene oxide, and (10) the Tishchenko reaction. The strength of basic sites relevant to different reactions is discussed based on the activity order among alkaline earth oxides, and the optimum pretreatment temperatures of MgO for different reactions. Reactions with hydrocarbons need strongly basic sites, whereas reactions with compounds containing functional groups proceed even on weakly basic sites. Finally, important issues to be investigated for the development of solid base catalysis are pointed out.

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“…Three diffraction peaks around 2h value 37.5°, 46°, 67°a scribable to c-alumina were observed for all the catalysts, indicating that the matrix of the catalysts retained. In addition, spectral characteristics belonging to K 3 AlF 6 phase appeared for the catalysts [19]. Note that the intensities of the lines changed with the catalysts and decreased in following order: fresh KF/Al 2 O 3 [ regenerated KF/ Al 2 O 3 [ third reused KF/Al 2 O 3.…”

Section: Reuse Of Catalystmentioning

confidence: 99%

KF/Al2O3 as Solid Base for the Synthesis of Polycarbonate Diols (PCDLs)

Feng

Ning

et al. 2007

Catal Lett

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Polycarbonate diols (PCDLs) are known as important intermediate for the manufacture of novel polyurethanes. In this work, a series of KF loaded oxides and alumina doped with potassium halides were prepared and employed as the catalysts for the PCDL synthesis via the reaction of hextane-1, 6-diols (HD) and dimethyl carbonate (DMC) followed by vacuum oligomerization. Experimental results indicated that among the catalysts tested, KF/Al 2 O 3 exhibited the best catalytic activity. Moreover, the catalyst could be reused for three times with acceptable catalytic activity. The basic centres with medium and strong strength generated through the interaction between KF and Al 2 O 3 were catalytically active for the reaction.

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Activity for base-catalyzed reactions and characterization of alumina-supported KF catalysts

Cited by 63 publications

References 23 publications

Synthesis of Biodiesel from Soybean Oil using Heterogeneous KF/ZnO Catalyst

Synthesis of Biodiesel from Soybean Oil using Heterogeneous KF/ZnO Catalyst

Solid Base Catalysts: Generation, Characterization, and Catalytic Behavior of Basic Sites

KF/Al2O3 as Solid Base for the Synthesis of Polycarbonate Diols (PCDLs)

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