Monolithic reactors are an attractive alternative to conventional multi-pha
se reactors. Advantages are the low pressure drop, the absence of a need fo
r a catalyst separation, and the large geometrical surface area. The main d
isadvantage is, however, the lack of practical experience with monolithic r
eactors. A pilot-scale study has been carried out to evaluate the performan
ce of a monolithic reactor on a larger scale. The results of this study hav
e demonstrated that a higher productivity can be obtained for a monolithic
reactor compared to a trickle-bed reactor for a solid catalysed gas-liquid
reaction that is mass transfer limited in the gas-phase reactant. A higher
selectivity has been demonstrated for the selective hydrogenation of benzal
dehyde towards benzylalcohol when a monolithic reactor is used instead of a
trickle-bed reactor as a result of the narrower residence-time distributio
n. (C) 2001 Elsevier Science B.V. All rights reserved.