Related Experiment Video
Updated: May 13, 2026

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes
Published on: August 5, 2016
Computational investigation of the pyrolysis product selectivity for α-hydroxy phenethyl phenyl ether and phenethyl
1Joint Institute for Computational Sciences, The University of Tennessee, Oak Ridge, Tennessee 37831, USA. bestea@ornl.gov
Abstract:
Using computational methods, we determine product selectivities for the pyrolysis of two model compounds for the β-O-4 linkage in lignin: phenethyl phenyl ether (PPE) and α-hydroxy phenethyl phenyl ether (α-hydroxy PPE). We investigate the dependence of the product selectivities on the number of reactant conformers included. Utilizing density functional theory in combination with transition state theory, we obtain rate constants for hydrogen abstraction reactions by the key chain-carrying radicals, which determine the product selectivity within a steady-state kinetic model. The inclusion of the energetically second lowest reactant conformer of PPE and α-hydroxy PPE has a large effect on the product selectivity. The final product selectivity computed for PPE agrees well with experiment. We find that the α-hydroxy substituent affects energetic as well as entropic contributions to the rate constant differently for alternative pathways of hydrogen abstraction and, thereby, significantly alters product distributions.
More Related Videos
Related Concept Videos
E1 Reaction: Stereochemistry and Regiochemistry
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Directing and Steric Effects in Disubstituted Benzene Derivatives
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.

