In situ reaction analysis
Gain insights into successful
scale-up when reaction
conditions and unstable
intermediates prohibit or
complicate extractive sampling
and offline measurements.
Gain insights into difficult chemistry
ReactIR - selective chlorination
™
In situ reaction analysis
Enhance understanding of difficult chemistry
with in situ IR products
Chlorinations are common processes for producing intermediates and active ingredients used
in the agricultural, pharmaceutical and fine chemical industries. The ability to determine the
chlorine substitution position and the relative degree is critical to formation of the desired product
as well as to control the formation of side products. Selectivity and yield of the reaction can be
optimized by timely end point determination.
The reaction conditions are corrosive and difficult to analyze
Although the Reaction Components have similar structures,
off-line. GC is one of the most common techniques utilized
the ReactIR™ is able to distinguish each component.
for end point determination, however it poses several
Peaks specific to each component are observed and easily
challenges. Sampling of the reactor is hazardous as the
followed. The undesired trichloro product has two unique
matrix is acidic and saturated with chlorine. The sample at
peaks which are shown in Figure 2.
time of analysis is not reflective of the reaction components
at the sampling time due to reaction progression. An
alternative technique to analyze the reaction progression
Figure 2: Reference spectra of reactant, product
and side product
is in-situ monitoring which eliminates errors due to off-line
sample analysis.
5 Sideproduct (red) overlayed
with reactant (black)
and Product (blue)
Figure 1: Reaction schemes
Neutra
Main reaction
R
R
Sideproduct (red) overlayed
Di Chloro
with reactant (black)
and Product (blue)
3
Mono
Chloro
2
+
+
cat
HC l
1
Cl
Cl
Cl
R
Poly
Chloro
Mono
Chloro
0
1600
Polychlorinated side product reaction
1400
1200
1000
800
Wavenumber (cm-1)
R
cat
+
+
C l2
Cl
Cl
Cl
Poly
Chloro
4
Cl
HC l
ReactIR™ capabilities
Cl
The trichloro side product absorbance at 1427 cm-1 is
Undesired side product product
isolated and readily detectible as observed above. The
R
sensitivity of the ReactIR™ allows for the immediate detection
1
+
+
Cl
C l2
Cl
Cl
Reference is UF 2006 Paper by Andrea Pastorio, Finchimica S.p.A, Italy
RCl
of this undesired species so the reaction can be stopped
before the product is compromised.
Ever wish you could
step inside your chemistry?
Figure 3: Trichloro side production formation
Seeing is believing
The Reaction End Point is determined by monitoring the
degradation of dichloro product, the formation of the trichloro
side product and the polychlorinated side product. In Figure 4,
Trichloro- Side Product
1427cm-1
the green profile is the product, the red is the reactant, the blue
is the trichloro side product and the black is the polychlorinated
Absortance
side product. As can be observed from these profiles, the product
formation levels off for a short period of time then begins to
degrade as the trichloro side product formation rate increases.
Thus, the end point of the reaction occurs over a brief period of
time and would be easily missed by off-line GC due to the time
Wavenumber (cm-1)
required for the analysis.
What ReactIR™ can do for you
Figure 4: ReactIR™ chlorination profiles
The Critical Process Parameter is to stop the reaction before the
trichloro side product has formed. Real-time, in situ, ReactIR
data is critical for accurate end point determination.
Heat
Increased selectivity/yield can be achieved through providing
Cl2 on
near instantaneous feedback on the undesired side product
Product
formation.
Better reaction control is a direct result of highly accurate endReaction end point
point determination.
Fewer failed batches result from monitoring the reaction in realtime, which allows for improved control of parameters which
impact batch quality.
Reactant
Trichloro
Increased safety is gained by eliminating human exposure to the
corrosive and hazardous reaction media.
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Selective chlorination
METTLER TOLEDO collected applications
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