Screening tests
Reaction calorimetry is a general test method as long as the studied process is accompanied by heat production or heat absorption. The true measurements in real time make the CPA200 to the ideal instrument for fast screening tests to find suitable reaction conditions.

The correct response to your changes of the experimental conditions will be presented directly and can momentarily be used for planning the next experimental step.

• Rapid catalyst screening
• Test of initiator systems for polymerization
• Test of reaction inhibitors
• Autocatalytic behaviour
• Kinetic- or mass-transfer controlled reactions.
• Raw material check

Experiment
Through continuous dosing of a fast initiator system the rate of reaction for emulsion polymerization of a number of monomers can be controlled.

The experiment below describes a screening test of a fast initiator system for the emulsion polymerization of vinyl acetate at 55°C. The initiator system was composed of hydroperoxide, a catalytic metal ion and ascorbic acid.

The pressure syringe from ChemiSens was used for small additions of reactants through a rubber septum into the reactor.

The hydroperoxide was used as a water solution. To minimize the thermal disturbances from the additions, the syringe was easily preheated in the CPA thermostatting bath.

A. The first addition of hydroperoxide resulted in a slow response. Probably due to residuals of inhibitor in the monomer.

B. By increasing the concentration of the metal ion catalyst (vanadium-oxo-sulfate) the activity of the initiator system was promoted.

C. A new addition of hydroperoxide gave a pronounced rate peak.

D. To further increase the initiator activity a new addition of the metal ion catalyst was made.

E, F. By further additions of both hydroperoxide and more metal ion catalyst the system was easily tested for suitable half-life times for the initiator system.