Efficient kinetic experiments in continuous flow microreactors

Abstract

Flow chemistry is an enabling technology that can offer an automated and robust approach for the generation of reaction kinetics data. Recent studies have taken advantage of transient flows to quickly generate concentration profiles with various online analytical tools. In this work, we demonstrate an improved method where temperature and flow are transient throughout the reaction. It was observed that only two orthogonal temperature ramp experiments under the same transient flow condition were sufficient to characterize a Paal-Knorr (one step bimolecular) reaction within our chosen reaction space. This method further shortens the time and decreases the materials needed to collect sufficient kinetic data and provides a framework with which more complex kinetic studies could be performed.

Kinetics Studies on a Multicomponent Knoevenagel−Michael Domino Reaction by an Automated Flow Reactor

“…[24][25][26][27][28][29][30] Based on these principles, advanced techniques for continuous-flow kinetics studies were introduced, which use transient flow or temperature profiles to investigate the kinetics of chemical reactions. [31][32][33][34] Thereby, the reaction progress was investigated on microreactors operating under non-steady-state conditions in order to eliminate the time necessary to reach steady-state operation and, consequently, to reduce the amount of consumed starting material, experiment time, and produced waste.…”

Catalytic Transformation of Biomass Derivatives to Value‐Added Chemicals and Fuels in Continuous Flow Microreactors

“…Multiphase flow in microreactors can achieve interfacial areas on the order of 10,000 m 2 /m 3 with an overall volumetric liquid phase mass transfer coefficient (k L a) between 1-10 s À 1 , considerably higher than in the conventional multiphase reactors. [188,189] Furthermore, they can be integrated with analytical equipment for on-line and high-throughput data acquisition. [131][132][133]180,185,186] Given the low amount of reagents handled in a microreactor and a fast heat removal for exothermic reactions, highly explosive reactions (e. g., using O 2 or H 2 under high temperatures and pressures) can be performed without significant safety risks.…”

“…The precise process control in microreactors allows kinetic data to be obtained more reliably. [188,189] Furthermore, they can be integrated with analytical equipment for on-line and high-throughput data acquisition. [190,191] The small microreactor size renders flow in the laminar regime under which regular (multiphase) flow patterns can be generated ( Figure 3).…”

Kinetic Analysis of Catalytic Organic Reactions Using a Temperature Scanning Protocol

“…used a temperature‐step protocol to optimize both temperature and reagent delivery in liquid‐phase batch and semi‐batch reactions that incorporated continuous heat flow kinetic measurements . More recently, Jensen has further developed a temperature scanning approach for flow reactors that exploits continuous spectroscopic monitoring where temperature and space velocity are changed simultaneously . Gavriilidis and coworkers have further developed this approach into an autonomous microreactor platform for rapid identification of kinetic models .…”

“…[5] More recently, Jensen has further developed a temperature scanning approach for flow reactors that exploits continuous spectroscopic monitoring where temperature and space velocity are changed simultaneously. [6] Gavriilidis and coworkers have further developed this approach into an autonomous microreactor platform for rapid identification of kinetic models. [7] A comparison of batch and ideal plug flow reactors equates distance or space velocity in flow with reaction time in batch.…”