Online process control for precise reaction endpoint determination in a purification process

Online reaction monitoring even for applications with a spectroscopically inactive component

Online measurement methods enable reliable reaction tracking in real time and ensure optimum control and safety in the production process. Conventional methods such as gas chromatography (GC), on the other hand, have the problem of time delays in recording measurement results, which is particularly problematic for process types in which precise reaction endpoint determination is crucial. This is the case with purification processes, for example.

During the production of an organic compound, the washing out of an impurity should be detected. This is done by checking the wash solution at the end of the process to ensure that a precisely defined amount of this impurity is present. The impurity to be removed cannot be detected spectroscopically but only by gas chromatography.

Use of a spectroscopically detectable component as a marker

However, another impurity is washed out of the filter cake, which is present in small quantities but is easily detectable in the ultraviolet spectrum (UV). The conversion of the reaction can be determined online by monitoring the decrease in this detectable reactant, although the actual parameter cannot be detected spectroscopically. Depending on the process environment, a transmission probe or measurement cell is installed either via a bypass or inline directly in the reactor. The signals recorded by the optical probe or measurement cell are transmitted to a spectrometer via fiber optics and analyzed. Due to its compactness and flexibility, the Hellma transmission measuring cell Excalibur Lab FFV is particularly suitable for applications of this type.


  •    The status of the washed-out contamination can be made available online and thus in real time despite a spectroscopically inactive component
  •     Elaborate sampling and analyses in the laboratory are no longer necessary and lead to considerable cost savings

Read the complete application note in our download section.


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