On-line monitoring of Brookhart polymerization by electrospray ionization mass spectrometry.

For the first time, an electrospray ionization (ESI) mass spectrometer coupled on-line with a microreactor permitted the fast screening of polymerization growth of alkenes in the liquid phase mediated by palladium Brookhart catalyst and allowed the direct mass spectrometric identification of alkyl chains still bonded to Pd. The method also allowed us to intercept the catalytically active cationic intermediates of the Brookhart polymerization of alkenes, and to prove on-line their catalytic activity through ion/molecule reactions. The technique is fast and sensitive, requires no sample preparation and manipulation, and is therefore suitable for the fast screening of catalyst/polymer growth by MS identification, with potential applications in areas such as new catalyst development, polymer chemistry, and product quality monitoring in manufacturing.