Biomedical Engineering Reference
In-Depth Information
11.6. CONCLUSION
As can be seen in this chapter which covers literature to 2010, immobilized reagents
have become valuable tools for powerful organic transformations with simple
separation procedures and recovery of catalysts from reaction mixtures. The area
has grown exponentially over the past decade with great interest being shown into
different support forms [53], immobilized catalysts [54], and asymmetric reac-
tions [55] increasing the synthetic possibilities. All these different reactions have
then been utilized in batch mode, in combination with microwave reactors [56], with
simple trickle bed reactors [57], or complex automated flow systems to give multistep
syntheses of complex molecules and pharmaceutically active compounds.
The combination of immobilized reagents and flow chemistry is beginning to
have a significant impact on howmodern synthesis is being conducted. Thesemethods
constitute a change in technology as well as a massive change in philosophy.
The adaptability and ease of scaling-up automated these chemical processes during
a 24/7 working environment using remote monitoring or control devices is especially
attractive [58]. Furthermore, as our knowledge of these methods improves, we can
envisage extensive multistep synthesis sequences coming within range of this
equipment in a relatively short time. The benefits that accrue using this equipment
are extensive, ranging from improved safety, hazardous molecule containment, high
pressure and temperature tolerances, improved heat/mass transfer, ease of optimi-
zation, and reaction consistency.
The ability to rapidly scale-up (scale-out) processes combined with telescoped
reaction steps and the reduction in solvent use are also attractive features to the new
technology. However, one should not underestimate that considerable experience and
synthesis knowledge are still required to derive the full benefits that the equipment has
to offer. Furthermore, we can expect considerable advances to be made in the area,
which will involve improved downstreamprocessingmethods, the use of gas reactors,
and how best to incorporate new strategically important chemistries.
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