Encapsulation of N,N′,N″-tricyclohexylguanidine in hydrophobic zeolite Y: Synthesis and catalytic activity

Sercheli, Ricardo; Ferreira, Alfredo L. B.; Guerreiro, Mário César; Vargas, Rogério Matheus; Sheldon, Roger A.; Schuchardt, Ulf

doi:10.1016/s0040-4039(97)00031-2

Cited by 31 publications

(9 citation statements)

References 8 publications

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“…The encapsulated guanidine showed a good catalytic activity in the addition reaction of benzaldehyde to acetone 71 . However, its activity in the transesterification of vegetable oils is low (14% conversion after 5 h 72 ), as the diffusion of the triglycerides through the channels of the Y zeolite is slow due to steric hindrance.…”

Section: Heterogeneously Catalyzed Processesmentioning

confidence: 99%

Transesterification of vegetable oils: a review

Schuchardt¹,

Sercheli²,

Vargas³

1998

J. Braz. Chem. Soc.

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980

539

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A transesterificação de óleos vegetais com metanol, bem como as principais aplicações de ésteres metílicos de ácidos graxos, são revisadas. São descritos os aspectos gerais desse processo e a aplicabilidade de diferentes tipos de catalisadores (ácidos, hidróxidos, alcóxidos e carbonatos de metais alcalinos, enzimas e bases não-iônicas, como aminas, amidinas, guanidinas e triamino(imino)fosforanos). Enfoque especial é dado às guanidinas, que podem ser facilmente heterogeneizadas em polímeros orgânicos. No entanto, as bases ancoradas lixiviam dos polímeros. Novas estratégias para a obtenção de guanidinas heterogeneizadas mais resistentes à lixiviação são propostas. Finalmente, são descritas várias aplicações para ésteres de ácidos graxos, obtidos por transesterificação de óleos vegetais.The transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. The general aspects of this process and the applicability of different types of catalysts (acids, alkaline metal hydroxides, alkoxides and carbonates, enzymes and non-ionic bases, such as amines, amidines, guanidines and triamino(imino)phosphoranes) are described. Special attention is given to guanidines, which can be easily heterogenized on organic polymers. However, the anchored catalysts show leaching problems. New strategies to obtain non-leaching guanidine-containing catalysts are proposed. Finally, several applications of fatty acid esters, obtained by transesterification of vegetable oils, are described.

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Section: Heterogeneously Catalyzed Processesmentioning

confidence: 99%

Transesterification of vegetable oils: a review

Schuchardt¹,

Sercheli²,

Vargas³

1998

J. Braz. Chem. Soc.

Self Cite

980

539

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“…Its alkylated molecules, alkylguanidines, are strong non-ionic organic bases with base strengths that are comparable to sodium hydroxide and the capability to catalyze liquid phase organic reactions such as methylation of phenol [109], Michael addition [110], alkylation of carboxylic acids [111] and transesterification [112][113][114][115][116][117]. Schuchardt and colleagues published several studies related to the application of alkylguanidine for the transesterification of triglyceride [112,113,116].…”

Section: Organic Solid Basesmentioning

confidence: 99%

“…The activity was slightly less than that of homogeneous system due to the hydrophobicity of the polymer support and the decreased symmetry of the alkylguanidinium cations, but the real issue was the leaching of active guanidine via nucleophilic attack of methoxide ion on the benzylic CH 2 group linking between the guanidine cation and polystyrene chain. The next strategies of heterogenizing alkylguanidine were encapsulation in the supercages of zeolite Y [114,116], entrapment in SiO 2 sol-gel matrices [116] and anchoring onto MCM-41 [116]. For the methanolysis of soybean oil, the FAME yield by these catalysts approached that of homogeneous counterparts after prolonged reaction time.…”

Section: Organic Solid Basesmentioning

confidence: 99%

Heterogeneous Base Catalysts for Transesterification in Biodiesel Synthesis

2009

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The heterogeneous base-catalyzed transesterification for biodiesel synthesis has been studied intensively over the last decade. This review classifies the solid base catalysts for transesterification into the following six categories based on Hattori's classification: single metal oxides, mixed metal oxides, zeolites, supported alkali/alkaline earth metals, clay minerals (hydrotalcites), and non-oxides (organic solid bases). The catalysts in each category have acceptable catalytic activities overall, and follow specific catalyst design rules, although not completely systematically, thereby drawing the best activity from them. In parallel, each catalyst is not versatile and has some limitations specifically related to its catalytic structure and properties. This review focuses on the heterogeneous base-catalyzed transesterification in terms of catalyst development, based on the published research, especially over the last decade.

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“…4), afforded an active catalyst for Knoevenagel condensations, Michael additions, and Robinson annulations [27]. In an alternative approach a bulky guanidine, N,N',N"-tricyclohexylguanidine was encapsulated in the super cages of hydrophobic zeolite Y to give a ship-in-a-bottle guanidine that catalyzed the aldol reaction of acetone with benzaldehyde, affording 4-phenyl-4-hydroxybutan-2-one [28]. …”

Section: Catalysis With Solid Acids and Basesmentioning

confidence: 99%

Atom efficiency and catalysis in organic synthesis

Sheldon

2000

Pure and Applied Chemistry

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730

322

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Abstract:The key to waste minimization in fine chemicals manufacture is the widespread substitution of classical organic syntheses employing stoichiometric amounts of inorganic reagents with cleaner, catalytic alternatives. The E factors (by waste per kg product) of chemical processes increase dramatically on going downstream from bulk to fine chemicals and pharmaceuticals, mainly owing to the use of "stoichiometric" methods. The concept of atom efficiency is a useful tool for rapid evaluation of the amount of waste generated by alternative processes. The general theme of atom-efficient, catalytic processes is illustrated with industrially relevant examples. These include catalysis by solid acids and bases, catalytic reductions and oxidations, catalytic C-C bond formation, asymmetric catalysis, biocatalysis, and catalysis in novel media (aqueous and fluorous biphasic systems, supercritical fluids, and ionic liquids).

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Encapsulation of N,N′,N″-tricyclohexylguanidine in hydrophobic zeolite Y: Synthesis and catalytic activity

Cited by 31 publications

References 8 publications

Transesterification of vegetable oils: a review

Transesterification of vegetable oils: a review

Heterogeneous Base Catalysts for Transesterification in Biodiesel Synthesis

Atom efficiency and catalysis in organic synthesis

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