Fabrication of Pd-based metal-acid-alkali multifunctional catalysts for one-pot synthesis of MIBK

The one-pot synthesis of methyl isobutyl ketone（MIBK） from acetone using multifunctional catalysts is an important sustainable organic synthesis method with high atom and energy efficiency.Herein. we report a series of Pd supported on mixed metal oxide（MMO） catalysts with controllable acidic/basic/metallic sites on the surface. We study the relationship between the nature, synergy,and proximity of active sites and the catalytic performance of the multifunctional catalyst in the tandem reaction, in detail. In the existence of Lewis acid and base sites, the catalysts with medium-strength acidic/basic sites show preferred activity and/or MIBK selectivity. For multifunctional catalysts, the catalytic properties are more than just a collection of active sites, and the Pd/Mg_3Al-MMO catalyst possessing 0.1% Pd loading and ~0.4 acid/base molar ratio exhibits the optimal 42.1% acetone conversion and 37.2% MIBK yield, which is among the best reported so far for this tandem reaction under similar conditions. Moreover, the proximity test indicates that the intimate distance between acidic/basic/metallic sites can greatly shorten the diffusion time of the intermediate species from each active site, leading to an enhancement in the catalytic performance.

One-pot conversion of cyclohexanol to ε-caprolactam using a multifunctional Na_2WO_4-acidic ionic liquid catalytic system

Na2WO4‐acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one‐pot conversion of cyclohexanol to ε‐caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid‐functionalized ionic liquids with HSO4? as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase‐transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate duringthe oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.

Ordered mesoporous Sn-SBA-15 as support for Pt catalyst with enhanced performance in propane dehydrogenation

A series of Sn‐incorporated SBA‐15materials with high specific surface areas and highly orderedmesoporous structures were synthesized by a facile one‐pot method and used as catalyst supports.A reference sample was also prepared using a conventional impregnation method.The catalystswere characterized using various methods,and their activities in propane dehydrogenation wereinvestigated.The incorporation of Sn into the SBA‐15matrix led to strong interactions between Snspecies and the support,and these helped to maintain the oxidation states of Sn species during thereaction.Substitution with Sn changed the interfacial properties of the Pt species and improved thefunction and effect of the Sn promoter.The catalytic activities and stabilities of the Pt catalysts supportedon Sn‐incorporated SBA‐15were better than those of the impregnated sample.However,thecatalytic performance deteriorated when an excessive amount of Sn was introduced and the interactionsamong Pt,Sn species,and the support became weaker.The Pt/0.5Sn‐SBA‐15catalyst gavethe best propene selectivity,i.e.,98.5%,with a corresponding propane conversion of about43.8%.