THE RELATIVE STABILITIES OF METAL DERIVATIVES OF SOME )-SUBSTITUTED ARYL AZO COMPOUNDS

262 Pages·9.546 MB·English

by  SNAVELY, FRED A

The Pennsylvania State College
The School of Chemistry and Physics
Department of Chemistry
The Relative Stabilities of Metal
Derivatives of Some ^-Substituted
Aryl Azo Compounds
A Dissertation
fey
Fred Allen Snavely
Submitted in partial fulfillment
of the requirements
for the degree of
Doctor of Philosophy
August 1952
Approved
bepartmedt of Chemistry
AUG 15 1952
Head or the department
Acknowledgement
The author wishes to express his indebtedness
to Dr. W. C. Fernelius for his encouragement and compe­
tent direction of this research problem; to Dr. B. P.
Block for his contribution to the theoretical section
and his criticism of the manuscript; to the research
group as a whole for the many hours of helpful dis­
cussion; to the dye companies for the many dyes furnished
by them; and to the Research Corporation, the Atomic
Energy Commission and the Alrose Chemical Company for
their financial support of this project.
He especially wishes to express his appreciation to
his wife, Emma, without whose complete cooperation through­
out his graduate study this manuscript could never have
been written. He also wishes to thank her for her as­
sistance in the preparation of this manuscript.
The Relative Stabi 15-ties of Metal
Derivatives of Some o-Substituted
Aryl Azo Compaounds
Table of Contents
Introduction...... ........... ............... 1
A. Historical.................. ............. 1
B. Statement of Objectives of Thesis....... 4
Symbols and Definitions of Terms............. 6
Mathematical Treatment........................ 8
Experimental Procedure....................... 21
Preparation of Reagents....................... 24
A. Acids and Bases .............. 24
B. Buffer Solutions.......................... 24
C. Metal Salts........................... . 25
D. Solvents................. ................. 25
E. Chelating Agents, List of, With Code
Numbers................................... 29
1. Preparation........................... 31
a. Diazotization of Amines.......... 31
b. Aryl Azo Resorcinol Compounds.... 33
c • Dye B-l.......................... 34
d. Dyes of Series E ................. 35
e. Dye H-l...... .................... 36
f. Dye 1-1....................... . 36
2. Purification.......................... 37
VI. Experimental....... .......................... . 45
A. Calibration of the pH Meter............... 45
B. Discussion of Constants Reported......... 50
C. Series A .......... •....................... 52
D. Series B....................... 60
E. Series C................................... 63
P. Series D ......... 74
G-. Series E***«............................... 77
H. Series F*......... 90
I. Series G-................ 112
J. Series H................................... 120
K. Series I............. 133
L. Series J................................... 136
M. Series K.........•...... '...............•«• 141
Other Dye Types........................... 144
N. Preparation of Metal Derivatives......... 146
0. Liquid-Liquid Extraction*................ 159
VII. Discussion of Results......................... 163
A. Order of Stability of Metal Derivatives.. 163
B. Relative Power of Coordination of the
Dyes**.*.................................. 166
C. Some Fundamentals Relationships*......... 169
D. • Structure of the Metal-Dye Compounds••••* 176
E. Future Work............................... 180
VIII. Summary ............... 184
IX. References......... 186
X. Appendices...................... 191
A. Appendix A. Method of obtaining the acid
dissociation constants and some sample...
calculations used in this work....... 191
5, Appendix B .................................. 19o
1. Data for Evaluating Utj.............. 197
2. Titration Data for Evaluating pK^
values for the chelating agents......... 199
G. Appendix C. Titration Data and Formation
and C Curve Data........... ....209
1. Series A .................... 210
2. Series B ........................... 213
3. Series C................. 214
4. Series D............................... 219
5. Series E............... 220
6. Series F. ................. 224
7. Series.G-.................... 239
8. Series H... . .......................... 245
9. Series.I..... 250
10. Series J ......................... 252
11. Series K....... 254
12. Series L, Thoron................... 255
I Introduction
A* Historical
The art of dyeing dates back to the earliest re­
corded times, and its actual beginning is lost in antiquity
The great advance in dyestuffs, however, did not occur un­
til Perkin in 1856 synthesized mauve the first man made
dye. Two years leter Griess, discovered the diazo reaction
Some azo colors were prepared from this reaction but were
of little commercial importance. The preparation of Congo
Red by Bottiger In 1884 started new research in this field.
Under rather favorable circumstances In Germany many new
azo dyes were prepared and the rapidly growing industry
was controlled by the Germans until the first World War.
In recent years in this country and abroad there has
been great activity in the field of metallated dye deriva­
tives. For example, in a recent issue of Chemical
Abstracts^, 26 abstracts deal specifically with azo dyes,
seventeen of which are concerned with patents on metal­
lized azo dyes. Aryl azo compounds with a hydroxy, amino
or carboxy group in one or more of the £-positions form a
large part of the type known as "mordant1* dyes. When these
dyes are used in the presence of metal salts, various color
tones can be developed with the same dye; the light and.
wash fastness is also generally improved.
This change in color in the presence of a metal salt
suggests that more than simple salt formation takes place.
2
Q
A.Werner was the first to give a convincing explanation
of the phenomenon when he observed that only those dyes
are "mordant" which posses the ability to form "inner
complex salts". An "inner complex salt" as defined by
3
Ley is a compound in which a metal ion is coordinated
to both a neutral and an acidic function occurring in the
same molecule, for example,
x 0— Cu
In the copper(II) complex, (I), of 1-(benzeneazo)-5-methyl-
2-phenol, the copper is bound by both an acidic oxygen and
a neutral azo group which themselves are attached to the
same molecule. This explanation is of course based on
4
Werner* s original coordination theory, the basic ideas of
which remain the same to-day.
Since that time much work has been carried out attempt­
ing to prove the formation of such compounds in the dyeing
process. Some workers in the dye industry have maintained
even to the present time that these "color lakes" are simply
the adsorption of the dye by the metallic hydroxides. The
answer no doubt in some instances lies some where in between..
Probably the strongest point in favor of compound formation
in the dyeing process is that dye coordination compounds have
been isolated. In fact, such compounds are at the present
time an important commercial article.
In spite of the Importance of such metal derivatives
to the dye industry only qualitative data are available as
to their relative stability. That is, only trial and error
can show which metal will form the most stable compound
with a certain dye. The metals used have generally been
restricted to a very few of which chromium(III) and copper(II)
El Q
are by far the most important. Drew and co-workers in
some excellent preparative work have shown that aluminum
derivatives are not as stable as chromium(III) dye complexes
in so far as their reactions toward acids are concerned.
Other investigators (see Sec. VI-N Preparation of Metallated
Dye Derivatives) have prepared metallated dye derivatives
but again no quantitative data are given on the stability
of the compounds formed.
Schwarzenbach,® searching for a color indicator for
magnesium and calcium, determined the formation constants of
these metal ions with Eriochrome Black T, (II), (C.I. 203)
and analogous compounds. The results show that the magnesium
compound is more stable than that of calcium. This then was
the first attempt at quantitative measurements on the relative
stability of the metallated derivatives.
OH HO
(II)
The large number of metallized dyes available, their wide
applications and possibilities, and the new problems posed
with each new fiber show the importance of investigations
in this field. There is an overwhelming supply of data
available on the above problems but the actual sparsity of
good quantitative data is hard to understand.
B. Statement of Objectives of Thesis
The primary aim of this investigation, then, was
to study the relative power of coordination of various
^-substituted aryl azo compounds with metal ions. This
could be accomplished by various methods, one of which
would be the preparation of metallated dye derivatives and
the subsequent evaluation of their dissociation constants,
i.e., a measurement of their tendency to ionize in solution.
However, since knowledge was also desired on the favorable
pH of formation of the metallated dye compounds, the method
10 11
of Bjerrum as modified by Calvin and Wilson for measur­
ing formation constants of the metal derivatives of weak
acids was best suited for the evaluation of the problem.
12—20
Other investigators in the field of coordination
chemistry have pointed out that with widely different
chelating agents (amines, be_ta-diketones, amino acids, etc.)
a certain order of stability with the compounds of metals
of oxidation state two appears to hold: Cu Ni Co Zn Pb Cd
Mg, given in the order of decreasing stability. This order
apparently shows that analytical specificity has little real
meaning with respect to the chelating groups represented in
the above studies.