Upgrading n-Butanol to Branched Alcohols over Ni/Ca_xMg_yO

Abstract

Despite the intensive development of heterogeneous catalysts with transition metal for the Guerbet reaction, a detailed understanding of the metal species and reaction mechanism (rate-determining step and active sites) is still deficient. Herein, we have developed a series of Ni/Ca x Mg y O catalysts to upgrade n-butanol into branched 2-ethyl-1-hexanol and establish the structure–activity correlation. Given the formation of solid solution between NiO and MgO, the addition of Mg element contributes to the formation of highly dispersed Ni nanoparticles with a small mean size. After optimization in reaction conditions, the highest conversion and selectivity of 80.2 and 79.1%, respectively, were achieved at 240 °C. The pivotal role of Ni0 sites and base sites during the Guerbet reaction, as confirmed by the selective poison experiments could be attributed to their synergistic catalysis during the dehydrogenation of n-butanol, which is the rate-determining step of the whole process. Moreover, a possible reaction mechanism for this rate-determining step over Ni/Ca x Mg y O catalysts was proposed based on experimental results. Overall, this work pushes forward the understanding of the reaction mechanism of the Guerbet reaction over transition-metal-decorated catalysts, which would be constructive for the rational design of heterogeneous catalysts.

Structural Evolution of MOF-Derived RuCo, A General Catalyst for the Guerbet Reaction

“…Our previous studies were aimed at the development of the optimized MOF-derived catalytic systems for the synthesis of isolated alcohol substrates, which are currently produced on large scales in a nonrenewable fashion. However, many Guerbet alcohols, with feature distinctive β-branching that engenders high liquidity and oxidative stability, find application in lubrication, paper processing and personal care products. ,, Yet, reports, especially of a recent nature, on self-condensation of short-chain alcohols other than ethanol to high-volume Guerbet alcohols have been scarce. ,,− Here, we show that MOF-derived alloys can function as general Guerbet catalysts with high catalytic activity for a suite of alcohol substrates, such as 1-propanol, 1-butanol and 1-pentanol. We have previously shown the superior catalytic performance of MOF-derived RuCo, formed in situ from bench stable precursors, over RuCo nanoparticles supported on a variety of traditional supports .…”

Upgrading of Aqueous Bioethanol to Higher Alcohols over NiSn/MgAlO Catalyst

“…The Ni 2p spectrum showed obvious spin−orbit splitting, which was mainly composed of Ni 2p 3/2 and Ni 2p 1/2 signal peaks and their corresponding satellite peaks. 31,32 The peaks of Ni 2p 3/2 and Sn 3d 5/2 as the main analysis object had been subjected to peak decomposing and a fitting procedure.…”

Construction of a (NNN)Ru-Incorporated Porous Organic Polymer with High Catalytic Activity for β-Alkylation of Secondary Alcohols with Primary Alcohols

“…However, these are homogeneous catalysts and separation and recycling is an impediment to their large-scale industrial use. Some heterogeneous catalysts, including IrO 2 /Fe 3 O 4 [37], Ni/Ca x Mg y O [38], SBA-15-supported Ir/NHC complex [39], Pt-Sn/γ-Al 2 O 3 [40], DMFstabilized Ir nanoclusters [41] have been developed for the cross-alkylation of alcohols to give β-alkylated secondary alcohols. However, these systems suffer from the need for relatively high temperatures, and/or long catalytic reaction time, intricate formulations.…”