Efficient Catalytic Conversion of Ethanol to 1-Butanol via the Guerbet Reaction over Copper- and Nickel-Doped Porous

Abstract

The direct conversion of ethanol to higher value 1-butanol is a catalytic transformation of great interest in light of the expected wide availability of bioethanol originating from the fermentation of renewable resources. In this contribution we describe several novel compositions of porous metal oxides (PMO) as highly active and selective catalysts for the Guerbet coupling of ethanol to 1-butanol in the temperature range 180−320 °C. The novel PMO catalysts that do not contain any noble metals are obtained by calcination of a series of hydrotalcite precursors synthesized through modular procedures. In particular, catalyst compositions simultaneously containing Cu and Ni dopants have shown excellent catalytic activities. Up to 22% 1-butanol yield at 56% ethanol conversion was reached in a batch mode; recycling and leaching tests showed excellent robustness of the new catalysts. An extensive characterization by means of several techniques such as powder XRD, SEM, TEM, BET, and NH 3 -and CO 2 -TPD was performed in order to understand structure−activity trends.

Complete lignocellulose conversion with integrated catalyst recycling yielding valuable aromatics and fuels

“…using a CuNi-PMO that was previously designed in our laboratory 28 . A model mixture consisting of 10 different alcohols was also successfully converted (Supplementary Note 6).…”

The Role of Copper in the Upgrading of Bioalcohols

“…Similar Ni, Cu, and Ni-Cu catalysts obtained by thermal decomposition at 460 8Co fh ydrotalcite (HT) materials were tested (Table1,e ntries 3-6) in the reactiono fe thanol at 310 8C and withoutaddition of ah omogeneous base. [18] Also in this case, the best catalytic activity was achieved with catalysts containing both metals,w ith conversion rising from 30.8 %f or the undoped materialu pt o6 2.4 %f or the 2:1 Cu:Ni catalyst and yield in 1-butanol from 5.6 %t o2 1.7 %f or the 1:1m aterial.…”

“…Similar Ni, Cu, and Ni‐Cu catalysts obtained by thermal decomposition at 460 °C of hydrotalcite (HT) materials were tested (Table , entries 3–6) in the reaction of ethanol at 310 °C and without addition of a homogeneous base …”

Investigation of the Reaction Pathways of Biomass‐Derived Oxygenate Conversion into Monoalcohols in Supercritical Methanol with CuMgAl‐Mixed‐Metal Oxide

“…[55][56][57] The rate of CÀC coupling to the mono-alcohols is similart ot he rate of Guerbet coupling of ethanol with copper catalysts in the literature. [33] The first step involves dehydrogenation of the reactant alcohol to an aldehyde or ketone followed by keto-enol tautomerization to the enol. [58] Since methanol cannot form an enol, formaldehyde is alwayst he electrophile during condensation.…”

“…Copperc atalysts have also been studied for Guerbet coupling of alcohols and conversion of diols to aldehydes and ketones,w hich includes many of the same reactions likely occurring in SCM-DHDO,i ncluding CÀC coupling, esterification, and dehydrogenation reactions. [9,[33][34][35][36] Despite the abundanceo fl iterature on glycerol conversion in water ando nc oupling of alcohols, to our knowledge no study has examined conversion of polyols in an alcohol solvent. The objective of this paper is to elucidate the chemistry that occurs for the SCM-DHDO of cellulose and cellulose derived chemicals by studying the SCM-DHDO of C 2 -C 4 oxygenates.…”