Branched Bio-Lubricant Base Oil Production through Aldol Condensation.

Invited for this month's cover is the group of Dionisios G. Vlachos at the Catalysis Center for Energy Innovation, University of Delaware. The cover design shows the application of renewable feedstocks to make a lubricant base oil that can be used in a racecar. The Full Paper itself is available at 10.1002/cssc.201901838.

Branched Bio-Lubricant Base Oil Production through Aldol Condensation.

Currently, lubricant base oils are derived from petroleum, a nonrenewable feedstock that contributes to greenhouse gas emissions. Bioderived, renewable lubricant base oils can mitigate environmental challenges and offer superior cold flow properties by incorporating branches to the base oil's hydrocarbon backbone with an appropriate synthetic strategy. A strategy was developed to synthesize branched alkanes for lubricant base oil in two steps from 12-tricosanone, obtained from bioderived fatty acids, and furfural, obtained from lignocellulosic biomass. The reaction pathway involves carbon-carbon coupling through aldol condensation followed by hydrodeoxygenation (HDO). Various solvents (non-polar, aprotic and polar, protic) and reaction conditions were screened to achieve a maximum yield of 94.3 % of aldol condensation products, containing the majority of a C33 furan (79.5 %) followed by a C28 furan (14.8 %). Subsequent HDO of aldol condensation products over an Ir-ReOx /SiO2 catalyst produced lubricant-ranged branched alkanes (C28 and C33 ) with 61.4 % yield and small fractions (<11 %) of alkanes with carbon numbers between C15 and C10 . The viscous properties of the produced bio-lubricant base oil were comparable to commercial petroleum-derived Group III and Group IV base oils. This approach serves as a potential stepping-stone to replace petroleumderived base oils and, in turn, reduce greenhouse gas emissions associated with current lubricant production.

Direct speciation methods to quantify catalytically active species of AlCl3 in glucose isomerization.

While homogeneous metal halides have been shown to catalyze glucose to fructose isomerization, direct experimental evidence in support of the catalytically active species remains elusive. Here, we integrate direct speciation methods with kinetics to provide strong evidence for the active species of AlCl3 in glucose-fructose isomerization in water. We investigate the effect of Lewis (AlCl3) and Brønsted (HCl) acids on aluminum hydrolysis and glucose conversion. We demonstrate the interplay between the acids using the Optimum Logic Inc. speciation model (OLI software). We measure aqueous aluminum species and protons through in situ and ex situ 27Al quantitative nuclear magnetic resonance (qNMR) and pH measurements, respectively, and quantify aluminum nanoparticles through a combination of inductively coupled plasma-mass spectrometry (ICP-MS), dynamic light scattering (DLS), and ultrafiltration. Direct speciation measurements correlated with the glucose isomerization rate indicate that the hydrolyzed Al(iii) complex [Al(H2O)4(OH)2]1+ is the active species in glucose isomerization.