Multistep
H2-free upgrading of alcohols to liquid hydrocarbons
is highly desirable for producing drop-in fuel substitutes, but the
limited reports of this process for select substrates require multiple
catalysts and bases, resulting in limited applicability. Direct conversion
processes that rely on multifunctional catalysts and do not require
base are yet to be reported. Here we describe such a Pd-catalyzed
deoxygenative coupling of heptanol with heterogeneous catalysts composed
of Pd immobilized on acid–base supports, which actively participate
in the reaction cascade. The supports include primarily basic MgO,
acidic γ-Al2O3, and Mg–Al hydrotalcite
(HT), with a combination of Lewis acidic and basic sites. Pd–HTs
with 1% and 5 wt % Pd loading afforded the highest overall activity
in the multistep cascade, yielding 30% hydrocarbons (tridecene 6-E-tridecene and tridecane) from a neat reaction with heptanol
with 0.2 mol % Pd loading. Heterogeneity tests suggest that Pd–HT
is operationally heterogeneous. The impact of support selection on
the activity and selectivity offers insights into the design principles
for next-generation catalysts for this process and related transformations.
<p>Design of active and selective supported catalysts is
critical for developing new tandem processes for upgrading biomass-derived
alcohols. Hydrogen-free upgrading alcohols to liquid hydrocarbons is desirable
for producing drop-in fuel
substitutes, but direct and atom-economical processes are yet to be
reported. Here we report a novel alcohol upgrading and<b> </b>deoxygenation cascade that
meets these criteria. This hydrogen-free cascade is catalyzed by
multifunctional Pd catalysts, whose supports feature a range of acid-base
properties: primarily basic MgO, acidic Al<sub>2</sub>O<sub>3</sub> and Mg-Al
hydrotalcite (HT) with a combination of Lewis acidic and basic sites. The
impact of support selection on selectivity offers insights into
the design principles for next-generation catalysts for this process and related
transformations.</p>
<p>Design of active and selective supported catalysts is
critical for developing new tandem processes for upgrading biomass-derived
alcohols. Hydrogen-free upgrading alcohols to liquid hydrocarbons is desirable
for producing drop-in fuel
substitutes, but direct and atom-economical processes are yet to be
reported. Here we report a novel alcohol upgrading and<b> </b>deoxygenation cascade that
meets these criteria. This hydrogen-free cascade is catalyzed by
multifunctional Pd catalysts, whose supports feature a range of acid-base
properties: primarily basic MgO, acidic Al<sub>2</sub>O<sub>3</sub> and Mg-Al
hydrotalcite (HT) with a combination of Lewis acidic and basic sites. The
impact of support selection on selectivity offers insights into
the design principles for next-generation catalysts for this process and related
transformations.</p>
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