World Journal of Chemical Education
ISSN (Print): 2375-1665 ISSN (Online): 2375-1657 Website: http://www.sciepub.com/journal/wjce Editor-in-chief: Prof. V. Jagannadham
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World Journal of Chemical Education. 2022, 10(1), 20-22
DOI: 10.12691/wjce-10-1-3
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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. Jagannadham2,

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

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

Pub. Date: January 03, 2022

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 σpara substituent constants for electron donating groups and Hammett σmeta 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 op-Directing groups m-Directing groups

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References:

[1]  James, Ashenhurst. "Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution". Master Organic Chemistry 2018, and one can visit the site https://en.wikipedia.org/wiki/Electrophilic_aromatic_directing_groups#cite_ref-5) for detailed information and Jerry March, Advanced Organic Chemistry, Reactions, Mechanisms, and Structure, 4th Edition, John Wiley & Sons, 1992, page 507-514.
 
[2]  Louis. P. Hammett, Physical Organiac Chemistry, McGrttw-Hill Book Co., New York, 1970.
 
[3]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, Education Journal 1 (2012) 1-4.
 
[4]  L. K. H. van Beek, Recueil des Travaux Chimiques des Pays-Bas 76, (1957) 729-732.
 
[5]  R. Sanjeev, V. Jagannadham, Adam A. Skelton and R. Veda Vrath, Asian J Chem 27 (2015) 3297-3302.
 
[6]  Data source: Tables of Physical & Chemical Constants (16th edition 1995). 2.1.4 Hygrometry. Kaye & Laby Online. Version 1.0 (2005); www.kayelaby.npl.co.uk.
 
[7]  David R. Lide, ed., CRC Handbook of Chemistry and Physics, Internet Version 2005, <http://www.hbcpnetbase.com>, CRC Press, Boca Raton, FL, 2005.
 
[8]  Corwin Hansch, A. Leo and R. W. Taft, Chem. Rev. 1991, 97, 165-195.