In this paper, proof of principle experiments and exploratory work that sol
ves the problem of ensuring that a gaseous and a liquid reactant are availa
ble at the catalytically active site at the same time by separating the rea
ction and the transport of the gaseous reactant. The equipment consisted of
an autoclave in which a feed was saturated with hydrogen, a reactor with a
catalyst coated on a monolith, a pump to circulate the feed/product stream
, and devices to control and monitor the process.
A lot of information of how the process can be practised was gathered durin
g the work. Conversion per pass should be below the amount of hydrogen that
can be dissolved in the liquid to avoid coke deposition (and hence deactiv
ation) of the catalyst. The effectiveness of the catalyst coated on the mon
olith was found to be 100%.
Several variations of the process design and catalysts used were explored.
Integration of the monolith with a heat exchanger will obviously allow for
the use of the process for very exothermic reactions like (nitro)benzene hy
drogenation. A monolith to which Rh-cyclooetadiene-1,2-bis-diphenylfosfino-
ethane (a homogeneous catalyst) was tethered was equally active in hydrogen
ation of 1-hexene as Rh-cyclooetadiene-1,2-bis-diphenylfosfino-ethane tethe
red to a standard alumina. This allows (fine)chemical producers to repeated
ly use the expensive homogeneous catalysts without the need for separation
of the catalyst from the reaction mixture. (C) 2001 Elsevier Science B.V. A
ll rights reserved.