One-step synthesis of methyl isobutyl ketone from acetone over Pd/MCM-22 zeolites

Yang, Piaoping; Shang, Yu; Yu, Jianfeng; Wang, Jun; Zhang, Milin; Wu, Tonghao

doi:10.1016/j.molcata.2007.03.037

Cited by 10 publications

(6 citation statements)

References 31 publications

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“…Microporous Brønsted acids provide confining voids of molecular dimensions surrounding acidic protons; such voids can confer unique reactivity and selectivity to these protons, in spite of the similar acid strength of aluminosilicates [12,13], through the selective diffusion of certain reactants and products or the preferential van der Waals stabilization of specific intermediates and transition states. Several zeolites have been reported to catalyze aldol condensations (MFI [10,11,[14][15][16][17][18][19], BEA [20,21], MWW [22], and FAU [14,19,23]), but ubiquitous deactivation and inhibition by co-products have precluded unequivocal mechanistic conclusions, making it difficult to assess even what type of acid sites account for condensation turnovers: acidic O-H groups [10], Lewis [19], or both types of acid sites acting in concert [19,24]. Sequential condensation reactions of α,β-unsaturated products form arenes [25,26] (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…1,3,5-trimethylbenzene from acetone condensation) that bind strongly onto Brønsted acid active sites, thus preventing those sites from catalyzing additional turnovers [14,27]. The presence of an intracrystalline Pt function has been reported to inhibit the formation of such arenes by hydrogenating the α,β-unsaturated intermediates to their saturated alkanone analogs before subsequent reactions [22,[27][28][29][30]. The practical implementation of these bifunctional strategies seeks to limit parallel acetone hydrogenation reactions by using Pt, which favors C=C over C=O hydrogenation [31,32], and low partial pressures of H 2 ; such strategies have led to incomplete inhibition of deactivation processes [22,[27][28][29][30], thus precluding kinetic measurements and rigorous assessment of intrinsic reactivities, which require stable catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Elementary steps in acetone condensation reactions catalyzed by aluminosilicates with diverse void structures

Herrmann

Iglesia

2017

Journal of Catalysis

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The unselective nature and ubiquitous deactivation of Brønsted acids in aldol condensations have precluded their practical use and unequivocal mechanistic assessments. H 2 and a Pt function are used here to confer stability by scavenging unsaturated intermediates to form stable products, thus allowing kinetic, spectroscopic, and isotopic assessments of elementary steps and their kinetic relevance, confirmed by density functional theory (DFT), for acetone condensation on microporous and mesoporous aluminosilicates (FER, TON, MFI, BEA, FAU, MCM-41). The selective titration of protons with 2,6-di-tert-butyl pyridine during catalysis shows that condensations occur exclusively on protons; the number of titrants required to suppress reactivity measures accessible sites and allows reactivity to be rigorously reported as turnover rates. Infrared spectra show that H-bonded acetone is present at saturation coverages during condensation catalysis. Taken together with rates that depend linearly on acetone pressure and with the absence of H/D kinetic isotope effects, these data indicate that condensation turnovers are mediated by the kinetically-relevant formation of a C-C bond via reactions of Hbonded acetone with another acetone molecule, a conclusion confirmed by DFT-derived free energies along the reaction coordinate. Measured rate constants reflect free energy differences between this transition state and its relevant precursors, a H-bonded and a gaseous acetone. These rate constants (per H + ) depend sensitively on size and shape of the confining voids among aluminosilicates of similar acid strength but diverse framework structure. Confinement effects are mediated by van der Waals contacts and are accurately described by energies derived from Lennard-Jones potentials of DFT-derived transition state structures; these energies are ensembleaveraged over all accessible configurations and T-site locations in each aluminosilicate framework. These energy descriptors replace incomplete metrics based solely on the sizes of voids and transition states, which fail to capture differences in reactivity among different confining frameworks.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Elementary steps in acetone condensation reactions catalyzed by aluminosilicates with diverse void structures

Herrmann

Iglesia

2017

Journal of Catalysis

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“…In a confined space of microporous zeolites, reactions of acetone over the Brønsted acid site selectively produce mesityl oxide. − The mesityl oxide can be hydrogenated to produce methyl isobutyl ketone, which is widely used as a solvent for paints, lacquers, and certain types of polymers and resins. The process can be carried out in a single step over bifunctional catalysts (e.g., Pt/H-ZSM-5, Pd/H-MCM-22, etc.). Aldol condensation is very important for the transformation of acetone to methyl isobutyl ketone. − …”

Section: Introductionmentioning

confidence: 99%

Adsorption and Tautomerization Reaction of Acetone on Acidic Zeolites: The Confinement Effect in Different Types of Zeolites

et al. 2010

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The adsorption and tautomerization reaction of acetone in H-FER, H-ZSM-5, and H-MCM-22 zeolites has been studied using full quantum calculations at the M06-2X/6-311+G(2df,2p) level of theory. The combination of a large quantum cluster and this meta-hybrid density functional results in reasonably accurate adsorption energies of -26.9, -28.1, and -23.9 kcal/mol for acetone adsorption in H-FER, H-ZSM-5, and H-MCM-22, respectively. Due to the acidity of the zeolite and the framework confinement effect, the tautomerization of acetone proceeds through a much lower activation barrier than in the isolated gas phase or in the presence of water molecules alone. The activation energies are calculated to be 24.9, 20.5, and 16.6 kcal/mol in H-FER, H-ZSM-5 and H-MCM-22, respectively. The endothermic reaction energy decreases with increasing of the zeolite pore sizes and amounts to 22.7, 17.6, and 15.9 kcal/mol for the reaction in H-FER, H-ZSM-5 and H-MCM-22, respectively. In addition, the adsorbed acetone enol is found to be highly unstable in the zeolite framework and readily reverse-transforms to adsorbed acetone with a very small activation energy. The activity trend and relative stabilities of the adsorbed keto and enol forms are well correlated with the interactions within the Brønsted acid site.

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“…The activity Pd or Pt supported on molecular sieves/zeolites like HZSM-5, MCM-22, MCM-56, MCM-49, Na/Cs-X catalysts for gas phase synthesis of MIBK has been subject several investigations [55][56][57][58][59][60][61][62][63]. The results obtained on these catalysts are summarized in Table 2.…”

Section: Miscellaneous Catalystsmentioning

confidence: 99%

Progress in One-Pot Synthesis of Methyl Isobutyl Ketone Using Multifunctional Layered Based Catalysts

Das

2013

KEM

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Methyl isobutyl ketone (MIBK) is one of the most widely produced and used aliphatic ketones worldwide. The one-step MIBK process with no intermediate separation steps using multifunctional catalysts is an important development towards greener organic synthesis and generates tremendous interest among the researcher across the globe. The single step process is facile and more economically viable and has provided opportunity to develop new and improved catalyst systems capable of operating under mild conditions. A widely variety of catalytic systems have been used in one-step process during last three to four decades. The progress in one-pot synthesis of MIBK using different multifunctional catalysts with special reference to layered based catalysts was critically reviewed in this article.

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One-step synthesis of methyl isobutyl ketone from acetone over Pd/MCM-22 zeolites

Cited by 10 publications

References 31 publications

Elementary steps in acetone condensation reactions catalyzed by aluminosilicates with diverse void structures

Elementary steps in acetone condensation reactions catalyzed by aluminosilicates with diverse void structures

Adsorption and Tautomerization Reaction of Acetone on Acidic Zeolites: The Confinement Effect in Different Types of Zeolites

Progress in One-Pot Synthesis of Methyl Isobutyl Ketone Using Multifunctional Layered Based Catalysts

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