Chemistry Reference
In-Depth Information
Fig. 7.39
Preparation of an
Mn(III)-salen complex and its
behaviour in epoxidations.
Fig. 7.40
Enantioselective catalysis
using supported ferrocenyl complexes.
very rare case of a heterogeneous enantioselective
catalyst dramatically outperforming its homoge-
neous counterpart, and indicates the very real poten-
tial of well-defined and designed heterogeneous
catalysts in this highly challenging area of chemistry.
with effort being expended to ensure that catalyst
preparation can be green. Much has been learnt
about the ability to control many of the key para-
meters, such as pore size, surface area, surface chem-
istry and particle size. Perhaps, more importantly,
the synthesis of many of these materials is remark-
ably simple. This is particularly true of the ambient
temperature and pressure conditions required for
the neutral templated materials, where template
removal also is simple to perform. These classes also
have the important advantage of template recovery.
Examples of significant progress in acid, base, oxi-
dation and enantioselective catalysis testify further
to the wide range of applicational areas in which
these catalysts have been applied with success. Much
has been learnt about the importance of surface pas-
sivation in many processes and further strides cer-
tainly will be made in the following few years. This
will require a combination of materials chemistry,
4 Conclusion
The use of highly structured mesoporous materials
in catalysis has developed remarkably rapidly since
the discovery of micelle-templated synthesis a
decade ago. A huge variety of structures has been
prepared, of which the silica-based materials have
been the most prolifically exploited. Their large pore
size has allowed them to be utilised in almost all
branches of organic chemistry with success and as
we learn more about their preparation and pro-
perties this trend will continue. Already, significant
progress has been made in materials preparation,
