Simplified Real-Time Mass Spectrometric Analysis of Reactions

Abstract

Dynamic information can be obtained on in-progress reactions in real time using a balloon-pressurized Schlenk flask in combination with an electrospray ionization mass spectrometer. The apparatus can be set up on a Schlenk line or in a glovebox and transported to the spectrometer, to be initiated by addition of catalyst or reactant by syringe through a septum. The system is demonstrated on palladium-catalyzed oxidation of phosphines.

Real-time analysis of Pd2(dba)3 activation by phosphine ligands

“…to reduce the activity of Pd-based catalysts and is therefore undesirable. 34,35 While often present in small quantities despite rigorous solvent degasification, heat served to accelerate this decomposition and effectively reduces the concentration of active catalyst in solution. Phosphine oxidation should be considered when preheating is employed while using simple phosphine ligands, though this side reaction can be avoided with oxidation-resistant ligands (vide supra).…”

Ionic Pd/NHC Catalytic System Enables Recoverable Homogeneous Catalysis: Mechanistic Study and Application in the Mizoroki–Heck Reaction

“…Ther eaction was carried out in DMF and online monitoring was performed by using a special pressurized sample infusion balloon interface recently developed by McIndoe andc o-workers. [19] At the initial point, monitoring was started by heatingt he reactionm ixture without the palladiumc omplex. After 3min, the solution containing the catalystp recursor was introduced through as eptum.T he first Pd-containing signal appearing in the spectra corresponded to [(NHC)PdI 3 ] À ,w hich quickly reachedt he maximum intensity and then decreased.…”

State-of-the-art mass spectrometry for point-of-care and other applications: A hands-on intensive short course for undergraduate students

“…Reaction acceleration, which has been a topic of two recent reviews, 29-30 and on-line reaction monitoring [31][32] were explored by students via the Katritsky transamination reaction (Figure 4a). 33 The Leidenfrost phenomenon 6 was first explained: a reaction mixture is deposited onto a surface heated significantly above the liquid's boiling point so that evaporating vapor forms a thermally insulating layer on which droplets of the reaction mixture are levitated.…”

“…39 Students were informed about the goal of quality by design, process analytical technology, and how on-line reaction monitoring is performed. [31][32]40 Students also were able to operate the miniature mass spectrometer and gained first-hand experience of the advantages and disadvantages the miniature instrumentation compared to benchtop counterparts. Issues such as portability, mass resolution, and power consumption were emphasized.…”