Ethanol Guerbet Condensation to n‐Butanol or C₄‐C₈ Alcohols over Ni/TiO₂ Catalyst

Abstract

Ethanol Guerbet condensation is an environmentally friendly process for preparing biofuel such as n‐butanol and alcohols with more than 4 carbon atoms. In this work, a multifunctional catalyst Ni/TiO2 was prepared by an excess impregnation method and its catalytic performance for ethanol Guerbet condensation was evaluated. The selectivity of C4‐C8 alcohols reached up to almost 70% (41.4% of n‐butanol) at nearly half conversion of ethanol at 210 °C and 10 h. Based on GC‐MS analysis results, the products in ethanol Guerbet condensation were identified and a reaction network was established. The presence of acetaldehyde and 2‐crotonaldehyde in the reaction products verified that Ni/TiO2‐catalyzed ethanol condensation followed the traditional dehydrogenation‐condensation‐hydrogenation reaction mechanism.

High Performing and Stable Cu/NiAlOx Catalysts for the Continuous Catalytic Conversion of Ethanol into Butanol

“…The catalytic upgrading of ethanol into butanol through the Guerbet coupling reaction, a well‐known industrial route for higher alcohol synthesis, have attracted widespread attention recently [10,11] . A commonly proposed mechanism for this process consists of a three‐step sequence of reactions, which involves an initial dehydrogenation step to form acetaldehyde, a subsequent aldol self‐condensation reaction to crotonaldehyde/butanal, and the final hydrogenation of the condensation product to butanol, as shown in Scheme 1 [12–14] . Meanwhile, a variety of byproducts, such as ethene, ether, ethyl acetate, hexanol, etc., might be also produced from the competitive side‐reaction owing to the complicated process [13,14] .…”

“…Generally, the rather complex Guerbet coupling reaction requires the catalytic system that possesses acidic, basic and dehydrogenation/hydrogenation properties simultaneously [12,14] . Appropriate selection of reaction conditions and rational development of the catalyst are of utmost importance for maximizing the yields of the target alcohols [13,15] . Therefore, a great challenge still lies in the rational design of multifunctional catalyst system for efficient production of butanol, particular in the long‐term continuous manner.…”

“…[10,11] A commonly proposed mechanism for this process consists of a three-step sequence of reactions, which involves an initial dehydrogenation step to form acetaldehyde, a subsequent aldol self-condensation reaction to crotonaldehyde/ butanal, and the final hydrogenation of the condensation product to butanol, as shown in Scheme 1. [12][13][14] Meanwhile, a variety of byproducts, such as ethene, ether, ethyl acetate, hexanol, etc., might be also produced from the competitive side-reaction owing to the complicated process. [13,14] Generally, the rather complex Guerbet coupling reaction requires the catalytic system that possesses acidic, basic and dehydrogenation/hydrogenation properties simultaneously.…”

“…[12][13][14] Meanwhile, a variety of byproducts, such as ethene, ether, ethyl acetate, hexanol, etc., might be also produced from the competitive side-reaction owing to the complicated process. [13,14] Generally, the rather complex Guerbet coupling reaction requires the catalytic system that possesses acidic, basic and dehydrogenation/hydrogenation properties simultaneously. [12,14] Appropriate selection of reaction conditions and rational development of the catalyst are of utmost importance for maximizing the yields of the target alcohols.…”

“…[12,14] Appropriate selection of reaction conditions and rational development of the catalyst are of utmost importance for maximizing the yields of the target alcohols. [13,15] Therefore, a great challenge still lies in the rational design of multifunctional catalyst system for efficient production of butanol, particular in the long-term continuous manner.…”