In the WP4 (Catalytic conversion of ethanol to butanol), bio-ethanol can be catalytically converted into butanol through alcohol dimerization called Guerbet reaction. This reaction is promoted by catalysts with a suitable combination of both acid and basic sites. Furthermore, the addition of an active metal can favour the initial dehydrogenation of the alcohol to form the carbonyl intermediate.
In the first year g-Al2O3, hydroxyapatite and MgO were synthesized as powders to obtain high surface area supports for dispersion of Ruthenium or Nickel. Textural, acid and basic properties of the three supports and redox properties of the metals were characterized in order to optimize the catalyst formulation. Ni/MgO and Ru/MgO provided the best butanol yields and were chosen to be upgraded to catalytic pellets for operation in the pre-pilot scale rig.
The activity of the second year was focused on the dispersion of Ni or Ru on commercial pellets following two main routes: i) deposition of metals on MgO pellets ii) deposition of metals on MgO-coated g-Al2O3 pellets. Reduction of volume of catalytic bed can be achieved provided that a uniform dispersion of the metal is obtained according to route i) or surface area of MgO is significantly enhanced by deposition onto alumina according to route ii). After determination and optimization of the technique for production of the best performing catalytic pellets, a suitable amount of catalyst will be supplied to HELBIO (Task 4.3) for the pre-pilot scale operation.