Temperature-rate profiles by polarimetric variable-temperature kinetic experiments to study racemization reactions
Related Experiment Video
Updated: Sep 30, 2026

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Giuseppe Alibrandi1, Salvatore Coppolino, Santi D'Aliberti
1Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Villaggio S. Agata, Messina, Italy. alibrandi@chem.unime.it
Abstract:
The racemization of (-)-adrenaline was followed by polarimetric variable-temperature kinetic experiments obtaining activation parameters and k(obs)(T) profile in one tenth of the time usually spent for traditional kinetic runs. A polarimeter connected to a computer for the acquisition and processing of the analytical data was used. The kinetic profiles were processed by both an integral method and a differential method. The results are in good agreement with each other and with those obtained by constant-temperature kinetics.
Related Concept Videos
Measuring Reaction Rates
Effect of Temperature Change on Reaction Rate
Temperature Dependence on Reaction Rate
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
Atomic Spectroscopy: Effects of Temperature
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
Thermal Sigmatropic Reactions: Overview
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...

