Some studies on aromatic nitration

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Iowa State University Capstones, Theses and
Retrospective Theses and Dissertations
Dissertations
1951
Some studies on aromatic nitration
Frank Joseph Modic
Iowa State College
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Modic, Frank Joseph, "Some studies on aromatic nitration " (1951).Retrospective Theses and Dissertations. 13726.
https://lib.dr.iastate.edu/rtd/13726
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SOME STUDIES ON AROivlATIG NITRATION
by
Prank Joseph Medio
A Dissertation Submitted to the
Graduate Faculty in Partial Fulfillment of
The Requirements for the Degree of
DOCTOR OP PHILOSOPHY
Major Subject: Riysical-Organic Chemistry
Approved:
Signature was redacted for privacy.
Signature was redacted for privacy.
[aj w Department
Signature was redacted for privacy.
Iowa State College
1951
UMI Number: DP12860
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TABLE OB' CONTENTS
ACKNOWLEDGMENT iv
INTRODUCTION 1
HISTORICAL REVIEW 3
The Mechanism of Nitration 3
Ortho-Para Ratios Sij.
EXPERIMENTAL 32
Ultraviolet Absorption Spectra ....... 32
Infra-red Absorption Spectra 32
Nitrobenzene 33
2,5-Uichloronitrobenzene 33
2,5-Dibromonitrobenzene 33
2,3"'Dinitro-l,l4.-dibromobenzene 33
2.5-Dinitro-l,ij.«dibromobenzen e 36
2.6-Dinitro-l,ij.-dlbromobenzen e 36
2,6-Dinitrobromobenzene. 37
2,3'*Dinitro-l,l|.-dichlorobenzene 37
2,5"Dinitro-l,l^.-dichlorobenzene . 37
2,6-Dinitro*l,ij.-dichlorobenzene. ...... 37
2-Nitro-i}.-chlorobromobenzene 39
ij.-Bromo-2-nitrochlorobenzene ij.0
£-Dibromobenzene-C^ I4.I
Acetanilide-C^. \\Z
lii
£-Bromoacetanilide-C^
£-Bromoani1ine- c'^k
jgi-Dibromobenzene-C^^ 1^3
Nitration Studies
Identification of High Temperature
Reaction Product. 1^5
Infra-red Spectrophotometrie Analytical
Methods ks
DISCUSSION $6
SUMIiARY 91
Iv
ACKNOWLEDGMENT
The author wishes to express his sincere gratitude
and thanks to Dr. G. S. Hammond for his advice and en­
couragement throu^out the course of tills study.
Appreciation is also expressed to the Institute
for Atomic Research for the use of their spectrophoto­
meters used during the covirse of this study, and for
providing the Aniline Hydrochloride
Appreciation is also expressed to Richard Hedges
for his assistance in obtaining the Infra-red spectra.
INTRODUCTION
In an effort to understaind the substitution re­
actions of benaene and its derivatives, the nitration
reaction has been extensively studied. This reaction
is particularly convenient for exsunination since it
is irreversible and easily controlled, forming rela­
tively stable products. The early work consisted of
the determination of the various isomers formed in
the nitration of different benzene derivatives and
the subsequent classification of the substituents as
either ortho-para or meta directing groups,^ Prom
competitive experiments with benzene, it was fo\ind
that ortho-para directing substituents were activa­
ting groups toward nitration and meta directing sub­
stituents were deactivating. It was from such work
that the general theories of aromatic substitution
were developed, since in nitration, as in all the other
common substitution reactions {i,e,, sulfonation, halo-
genation, alkylation, and acylation) the attacking spe­
cies was shown to be electrophilic and, therefore, at­
tack occurred at centers of high electron density.
1. A. F. Hollenmn, "Die direkte Einfuhrung von Sub-
stituenten in den Benaolkern," Leipzig, 1910j Chem,
Revs,. 1, 187 (I92ii.),
-2-
In recent years, the mechanism of aromatic nitra-
2
tion has been the subject for numerous studies. Sev­
eral anomalies, however, still exist, one of these be­
ing the ortho-para ratio obtained upon the nitration
of the derivatives of benzene. The few theories ad­
vanced to account for ortho-para ratios are not suf­
ficient to explain the observed experimental results.
It was with the idea of attempting to elucidate these
facts that this work was ^^ndertaken. The problem is
one of general interest since a better understanding
of the factors involved in aromatic nitration will
necessarily lead to a more complete understanding of
substitution reactions in general.
2. For an extensive review, see: R, J, Gillespie and
D. J. Millen, Quart. Revs.. 2, 277 USW.