One-Pot Liquid-Phase Catalytic Conversion of Ethanol to 1-Butanol over Aluminium Oxide—The Effect of the Active Metal on the Selectivity

Abstract

Direct catalytic valorization of bioethanol to 1-butanol over different alumina supported catalysts was studied. Thirteen (13) heterogeneous catalysts were screened in search for the optimal material composition for direct one-pot conversion of ethanol to 1-butanol. For the most promising catalyst, a 25% ethanol conversion with 80% selectivity (among liquid carbon products) to 1-butanol could be reached at 250 °C. Additionally, the reaction kinetics and mechanisms were further investigated upon use of the most suitable catalyst candidate. OPEN ACCESSCatalysts 2012, 2 69

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

“…An almost complete conversion of BuOH can be obtained for temperatures below 350°C, while at higher temperatures, a minor fraction of BuOH (<5 mol%) remains unreacted. Riittonen et al 68 reported a theoretical maximum conversion of 98.5% for the condensation of ethanol to n-butanol at 250°C and 70 bar, and Olcese and Bettahar 101 calculated a thermodynamically favorable equilibrium for the Guerbet reaction of ethanol both in vapor and in liquid phase. The first step in the generally accepted reaction pathway is the dehydrogenation of the reagent alcohol to the corresponding aldehyde or ketone (Scheme 2, R2).…”

“…7,[106][107][108][109] For liquid phase reactions, hence at increased pressure, the detrimental effect of water on conversion and selectivity is often reported. 36,68,[110][111][112] Although this is generally caused by a deactivating effect on the catalyst, water could also influence the thermodynamic equilibrium of the aldol condensation. It might slow down the desired reaction pathway, thereby leaving intermediate aldehydes …”

“…Riittonen et al studied different transition metals (Ru, Rh, Pd, Pt, Au, Ni and Ag) supported on alumina for liquid phase ethanol condensation without addition of a specific base at a temperature of 250°C. 68 Interestingly, a commercial Ni/Al 2 O 3 catalyst showed high selectivity for n-butanol. After optimization of the reaction conditions, a high selectivity (80%) was obtained at a conversion of about 25% after 72 hours.…”

“…Many publications focus on the Guerbet selfcondensation of ethanol for the production of n-butanol and higher alcohols. [65][66][67][68][69][70][71][72][73][74][75][76][77][78] Just like ethanol, n-butanol can be used as a renewable fuel, yet in comparison with ethanol, it has a higher energy density, a lower volatility and a lower propensity to absorb water. Methanol on the other hand lacks a second carbon atom and cannot self-condensate by Guerbet condensation.…”

Role of Different Feedstocks on the Butanol Production Through Microbial and Catalytic Routes

“…The authors observed that the hydrogenation capacity of the catalyst as well as selectivity to n-butanol increases with increase in concentration of Mg ( Carvalho et al 2012). Riittonen et al (2012) studied one-pot liquid-phase catalytic conversion of ethanol to 1-butanol over aluminium oxide. They examined and screened thirteen (13) heterogeneous catalysts in search for the optimal material composition for direct one-pot conversion of ethanol to 1-butanol.…”