Chemistry Reference
In-Depth Information
be optimized in a fully automated fashion. Such automated microreactor
systems allow for rapid screening of reaction conditions, which is of
great interest for the fine chemical and pharmaceutical industries. A self-
optimizing system was used for the optimization and scale-up of a Mizoroki-
Heck reaction between 4-chlorobenzotrifluoride and 2,3-dihydrofuran
(Figure 13.12).
38
The reagents were introduced into a microreactor and
samples were automatically taken by an inline HPLC system. HPLC was used
to determine the conversion, yield and selectivity of the reaction and the
data were analyzed via computer with DoE (Design of Experiments) software.
Feedback was given with regard to the subsequent experiment and resulted
in an adjustment of the concentrations and flow rates. After 19 automated
experiments, the optimal yield and selectivity were found. Next, these opti-
mized reaction conditions were transferred to a mesoscale flow reactor
system, which provided a 50-fold scale-up without further reoptimization.
The vinylation of aryl halides via a Mizoroki-Heck reaction with ethylene
is a challenging transformation in batch mode owing to poorly defined
interfacial contact between the gas and liquid phases. Owing to the en-
hanced gas-liquid mass transfer, excellent mixing and the ability to process
flammable gases in a safe and reliable fashion, the use of microreactors for
gas-phase reactions has become popular.
39
More specifically, membrane
reactors have been utilized to establish ecient gas-liquid contact. The gas
O
Pd(OAc)
2
(1 mol%)
t
Bu-MePhos (3 mol%)
Cl
O
F
3
C
+
Cy
2
NMe,
n
-butanol
+
CF
3
F
3
C
O
F
3
C
Step 1:
Automated optimization of a chemical reaction
Step 2:
Scale-up of the chemical reaction
Reagents
Products
Microreactor
Micr oreactor
50-fold increase
Temperature
Control
Flow Rate
Control
inline HPLC
- mesoscale continuous-flow reactor
Data
Analysis
Computer
Figure 13.12
Self-optimization of the reaction conditions for a Mizoroki-Heck
alkenylation by means of an automated ''intelligent'' microfluidic
system and its subsequent scale-up in a mesoscale continuous flow
reactor.
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