Non-traditional three-phase reactor setup for simultaneous acoustic irradiation and hydrogenation

A tailor-made autoclave setup for simultaneous acoustic irradiation and hydrogenation was used in the hydrogenation of fatty acids and carbohydrates. The aim was not to perform actual sonochemistry but to retard deactivation of the catalyst by means of acoustic irradiation. The catalyst used was a Raney nickel one that tends to deactivate quite rapidly from batch to batch. The results indicated that in the case of the aqueous system (xylose hydrogenation to xylitol) the effect is clear. In the case of the fatty acids one actually observed an enhancement of the reaction rate: with recycled catalyst the second and third batch proceeded somewhat faster than the first one. (C) 2003 Society of Chemical Industry.