Is Hammett Correlation of Dipole Moments of mono-Substituted Benzenes Helpful to Distinguish o,p-Directing Groups from m-Directing Groups in an Aromatic Electrophilic Substitution? A Chemical Education Perspective

R. Sanjeev¹, D. A. Padmavathi² and V. Jagannadham^2,

¹Department of Chemistry, Geethanjali College of Engineering and Technology, Cheeryal-501301, Telangana, India

²Department of Chemistry, Osmania University, Hyderabad-500007, India

Cite this paper

R. Sanjeev, D. A. Padmavathi and V. Jagannadham. Is Hammett Correlation of Dipole Moments of mono-Substituted Benzenes Helpful to Distinguish o,p-Directing Groups from m-Directing Groups in an Aromatic Electrophilic Substitution? A Chemical Education Perspective. World Journal of Chemical Education. 2022; 10(1):20-22. doi: 10.12691/WJCE-10-1-3

Abstract

In chemistry literature it is so far achieved to distinguish o,p-directing groups from m-directing groups purely on the basis of only relative yields of ortho, para and meta electrophilic substituted products in the benzene ring and it is also based on their ability to disturb the pi-electron density at the carbons. It is for the first time in chemistry literature using dipole moment data a linear free energy relationship (LFER), Hammett equation is used to distinguish o,p-directing groups from m-directing groups. This could be achieved by constructing Hammett plots with dipole moments versus Hammett σ_para substituent constants for electron donating groups and Hammett σ_meta substituent constants for electron withdrawing groups. Good straight lines are obtained with correlation coefficients close to 0.9 with certainly an unmistakable trend.

Keywords

hammett equation, dipole moments, o,p-Directing groups, m-Directing groups

Copyright

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References

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