PNNL

Abstract

A series of multicyclic hydrocarbons were synthesized in high yield and under mild conditions from 2,5-hexanedione, cyclohexanone and cyclopentanone, at scales of 200 g. Aldol products were obtained with conversions of 97%, 80-90% and 70% respectively, based on the consumption of starting materials. Cyclopentanone and cyclohexanone aldol condensations resulted in mixtures containing mainly the bicyclic products (90%) as well as tricyclic analogs (10%). The 2,5-hexanedione aldol condensation produced 50% methylcyclopentenone (MCP) as expected and about 50% oligomers. Surprisingly, the complex heavy fraction after removal of MCP contained mainly products of Michael addition of MCP and not self-aldol condensation products of MCP or MCP and 2,5-hexanedione. The hydrogenation-hydrodeoxygenation (HYD-HDO) of cyclohexanone- and cyclopentanone-derived reactants under nickel on alumina (Ni-Al2O3) catalyst at 250 °C and pressures between 800 to 1200 psig produced the expected saturated hydrocarbons with good recovery (80% and 76% respectively), with only small amounts of oxygenated residual starting materials remaining (