Ralph N. Landau

Reaction calorimetry as an in-situ kinetic tool for characterizing complex reactions☆

Abstract Due to its ability to provide directly reaction rate data and its in-situ nature, reaction calorimetry has become one of the most powerful probes of reaction pathways and mechanisms of chemical reactions by virtue of providing high-quality kinetic data. In this paper, examples of enantioselective hydrogenation and selective consecutive hydrogenation reactions are presented to demonstrate the high quality of kinetic data obtainable from the reaction calorimetry. They are also used to illustrate the use of reaction calorimetry for elucidating reaction pathways and mechanisms from detailed kinetic and thermodynamic information about individual step involved in multi-step reactions that is otherwise difficult to obtain without calorimetry.

Kinetic influences on enantioselectivity in asymmetric catalytic hydrogenation

Examples from both homogeneous and heterogeneous catalytic systems are presented which demonstrate the role that reaction dynamics may play in dictating the ultimate enantioselectivity observed in asymmetric hydrogenation reactions. The hydrogenation of allylic alcohols using Ru(S)-binap and the hydrogenation of α-keto esters using cinchona-modified supported Pt are discussed. This work highlights the importance of considering reaction kinetics in addition to the stereochemical aspects of the chiral catalytic environment in interpreting catalytic behavior in asymmetric hydrogenation reactions.

Process development utilizing advanced technologies: the RC1 reaction calorimeter, the multifunctional SimuSolv software, and the ReactIR reaction analysis system

In-situ FTIR has been used to monitor reactions occurring in an automated laboratory calorimeter. The study successfully acquired both Arrhenius parameters and heats of reaction from a single experiment. The combination of enhanced control and measurement sensitivity affords an efficient method of reaction monitoring and process development. In addition to providing composition monitoring, the FTIR-based analysis system revealed reaction pathway information. The highly controllable automated laboratory calorimeter accurately and precisely regulated and recorded reaction conditions leading to the estimation of model parameters with high confidence.