Synthesis of Mixed Alcohols From Biomass Using Slurried Nano-Sized Metal Particles

Molybdenum disulfide (MoS₂), anchored on a support, is a catalyst of choice to synthesize mixed alcohols, also known as Higher Alcohols Synthesis (HAS) process. However, the process suffers from low space-time-yield (STY) and poor selectivity under high temperature (300^o – 325^oC) / high pressure (10-20 MPa) operation that makes it unattractive for any commercial application. We are investigating the use of nano-sized MoS₂, to enhance catalyst activity and increase selectivity to alcohols under less severe operating conditions.

The nanocatalysts were synthesized from a slurry of molybdenum hexacarbonyl (Mo(CO)₆) and elemental sulfur (S) in hexadecane solvent  at 70^oC using sonication. The decomposition of Mo(CO)₆ was monitored that yielded a first-order rate constant  of 3 x 10^-4 min^-1 with an R value of .997. The TEM, SEM, IR, and Raman techniques were used to characterize MoS₂ nanoparticles. The TEM data showed the mean particle size to be 5 nm. A mini-pilot unit, fitted with a 1- liter slurry reactor, has been set up to evaluate syngas conversion catalysts. Work is underway to evaluate nano MoS₂ slurried in a high molecular weight solvent for conversion of premixed H₂/CO in a 2:1 ratio to mixed alcohols.