Synthesis of Branched Octahydro-Indene with Methyl Benzaldehyde and Methyl Isobutyl Ketone

Branched octahydro-indenes were first synthesized with methyl isobutyl ketone (MIBK) and methyl benzaldehyde, which can be obtained from lignocellulose. Initially, C14 oxygenates were prepared by the aldol condensation reaction of MIBK with methyl benzaldehydes. K2CO3/Al2O3 exhibited the highest activity among the studied solid base catalysts. On the basis of the characterizations, the outstanding activity of K2CO3/Al2O3 was comprehended, because this material has a relatively higher surface area and a larger base site concentration. Subsequently, the aldol condensation products were converted to branched octahydro-indene by hydrodeoxygenation over a Pt/C catalyst. This method is also applicable for the manufacture of C11–C13 polycycloalkanes with methyl benzaldehyde and other lignocellulosic ketones. According to our measurements, the polycycloalkanes obtained in this work have low freezing points (227.7∼240.0 K) and high densities (0.857∼0.944 g mL–1). Consequently, they may potentially be utilized to raise the volumetric heat values and/or the thermal stability of jet fuels.