Multifunctional Catalysts for Direct Conversion of Alcohols to Long-Chain Hydrocarbons via Deoxygenative Olefination

Multistep H-2-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 , OH 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 gamma-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.