PREPARATION AND THERMAL
DECQMPOSITION OF SOME
UNSIMMETRICAL TIIENOYL
BENZOYI. PERDXIDES

Thesis for the Degree of M. S.
MICHIGAN STATE UNIVERSITY
DELOS RUSSELL BYRNE
1966

  
 
 

  
 
  

LIBRA 7?. Y
Midngan Staifl
University

«H695

 

   
    

 
  
 

BINDING BY

nuns & SONS'
999K Emma

ABSTRACT

PREPARATION AND THERMAL DECOMPOSITION OF SOME
UNSYMMETRICAL THENOYL BENZOYL PEROXIDES

by Delos Russell Byrne

This investigation deals with the preparation
and thermal decomposition of a new series of unsymmetrical
peroxides of the structure shown below, containing one

benzene and one hetero—aromatic ring.

/CH3
h l
s/T°‘°

O

 

A total of eight compounds were synthesized and six were
selected for kinetic investigation. With one exception
the compounds investigated kinetically were derivatives
of 2-thenoyl benzoyl peroxide either unsubstituted or
substituted in the 5-position of the hetero-aromatic ring.
3-Thenoyl benzoyl peroxide was included for comparison.

In all cases investigated the thermal decompo-
sition followed strict first-order kinetics. The rate
constants and half-lives at 82.l7° in presence of styrene

as a radical scavenger are listed below:

Delos Russell Byrne

k x 19%
Peroxide (min. ) Tl/2 (min.)
2-Thenoyl Benzoyl 4.00 173
3-Thenoyl Benzoyl 3.62 191
(5-Methyl-2-Thenoy1) Benzoyl 5.01 139
(S-Ethyl-2—Thenoyl) Benzoyl 5.19 134
(5-t-Butyl-2-Thenoyl) Benzoyl “.69 1M8
(S—Nitro—2-Thenoy1) Benzoyl “.93 1A1

The kinetic experiments were conducted at three
temperatures: 72.90, 82.17 and 90.35° in Spectrograde
carbon tetrachloride,0.1000 molar in peroxide and 0.2
molar in styrene. The experiments were conducted in a
purified nitrogen atmosphere in the absence of light to
prevent decomposition. Peroxide concentrations were de—
termined by infrared technique; rate constants and acti-
vation energies were calculated by the least square method
using a 3600 CD0 computer at Michigan State University.
Frequency factors and activation entrOpies were then cal-
culated from the Eyring absolute rate equation.

The data indicated that substituents increase
the decomposition rate regardless of the electron donating
or withdrawing character of the group. It appears that
the increase in reaction rate is related to the displace-
ment of the bonding electrons in one direction or the other
from the central oxygen-oxygen bond. There may be a steric

effect involved, specifically a case of "steric assistance."

PREPARATION AND THERMAL DECOMPOSITION OF SOME

UNSYMMETRICAL THENOYL BENZOYL PEROXIDES

By

Delos Russell Byrne

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Chemistry

1966

 

 

To My Mother, Mrs. Annabelle Tenney

ACKNOWLEDGMENT

The author wishes to express his sincere appre-
ciation to Professor Robert D. Schuetz for his helpful
guidance throughout the course of this investigation.

Thanks are also expressed to the Petroleum
Research Fund of The American Chemical Society for their
financial support.

Special acknowledgment is extended to the
author's close friend and associate, Dr. Fred M. Gruen,
for many enlightening discussions and for his sincere

encouragement.

iii

TABLE OF CONTENTS

Page

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . iii

LIST OF TABLES . . . . . . . . . . . . . . . . . . . Vi

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . viii
Chapter

I. INTRODUCTION AND HISTORICAL 1

II. EXPERIMENTAL . . . . . 8

Chemical Reagents - . . . . . . . . . . . . 8

Syntheses . 8

2-Acetylthiophene . . . . . . . . . . 8

2-Then01C AC id 0 o o o o o o o o o o o o O 9

3-Cyanothiophene . . . . . . . . . . . . . 10

3-ThenOiC AC id 0 o o o o o o o o o o o o 0 ll

2- -Ethylthiophene . . . . . . . . . . . 11

5- Ethyl- -2- -Acetylthiophene . . . . . . . . 12

5- “Ethyl -2-ThenOiC ACid o o o o o o o o o 0 l3

5- t- -Butyl- -2-Thenoic Acid . . . . . . . . . 14

2-Thenal o o o o o o o o o o o o o o o 15

S-Nitro- 2-Thena1 . . . . . . . . . . . . l6

5- Nitro- 2- Thenoic Acid . . . . . . . . . . 17

Preparation of Thenoyl Chlorides . . . . . . l9

2- -Thenoyl Chloride . . . . . . . . . . . . 19

Sodium Perbenzoate . . . . . . . . . . . 21

2-Thenoy1 Benzoyl Peroxide . . . . . . . . 22

3— —Thenoyl Benzoyl Peroxide . . . . . 23

(3-Methyl- 2- Thenoyl) Benzoyl Peroxide . . 23

(S-Methyl- 2-Thenoyl) Benzoyl Peroxide . . 2“

(S-Ethyl-2-Thenoyl) Benzoyl Peroxide . . . 25

(5-t-Butyl-2—Thenoyl) Benzoyl Peroxide . . 26

(5-Nitro-2-Thenoyl) Benzoyl Peroxide . . . 27

2-Furoyl Peroxide . . . . . . . . . . . . 29

Kinetic Determinations . . . . . . . . . . . 29

iv

TABLE OF CONTENTS (Continued)

Chapter Page
III. RESULTS AND DISCUSSION . . . . . . . . . . . 32
IV. SUMMARY . . . . . . . . . . . . . . . . . . 38
LITERATURE CITED . . . . . . . . . . . . . . . . . . 39
APPENDIX . . . . . . . . . . . . . . . . . . . . . . U2

LIST OF TABLES

Table Page
1. Preparation of acid chlorides . . . . . . . . . 20
2. Peroxides prepared . . . . . . . . . . . . . . 28
3. Comparison data of symmetrical and unsymmetri-

cal peroxides . . . . . . . . . . . . . . . . 36
A. Spectroscopic measurements leading to kinetic

data of 2-thenoy1 benzoyl peroxide at 72.90°. U3

5. Spectrosc0pic measurements leading to kinetic
data of 2-thenoyl benzoyl peroxide at 82.17°. AA

6. Spectroscopic measurements leading to kinetic
data of 2-thenoyl benzoyl peroxide at 90.35°. 45

7. Spectroscopic measurements leading to kinetic
data of 3-thenoy1 benzoyl peroxide at 72.900. A6

8. SpectrOSCOpic measurements leading to kinetic
data of 3-thenoyl benzoyl peroxide at 82.l7°. 47

9. SpectrOSCOpic measurements leading to kinetic
data of 3-thenoyl benzoyl peroxide at 90.35°. “8

10. Spectrosc0pic measurements leading to kinetic
data of (5—methy1-2-thenoyl) benzoyl per-
oxide at 72.90° . . . . . . . . . . . . . . . “9

ll. Spectroscopic measurements leading to kinetic
data of (5-methyl- 2- thenoyl) benzoyl per-

oxide at 82. 17° . . . . . . . . . . . . 50
12. Spectrosc0pic measurements leading to kinetic

data of (5-methyl- 2- thenoyl) benzoyl per-

oxide at 90. 35° . . . . . . . . . . . . . 51

l3. SpectrOSCOpic measurements leading to kinetic
data of (5- -ethyl- -2- Othenoyl) benzoyl peroxide
at 72. 90° . . . . . . . 52

vi

 

 

Table

1A.

15.

l6.

17.

18.

19.

20.

21.

22.

LIST OF TABLES (Continued)

Page
Spectroscopic measurements leading to kinetic
data of (5-ethy1-2-thenoy1) benzoyl peroxide
at 82.170 . . . . . . . . . . 53

Spectroscopic measurements leading to kinetic
data of (5-ethyl-2—thenoyl) benzoyl peroxide
at 900350 0 o o o o o o o o o o o o o o o o o 5“

Spectrosc0pic measurements leading to kinetic
data of (5-t-butyl-2-thenoy1) benzoyl per-
oxide at 72. 90° . . . . . . 55

Spectroscopic measurements leading to kinetic
data of (5-t-butyl-2-thenoyl) benzoyl per-
OXide at 82.170 c o o o o o o o o o o o o o o 56

Spectros00pic measurements leading to kinetic
data of (5- t- -butyl- -2- thenoyl) benzoyl per-
oxide at 90. 35° . . . . . . . . . . . . . . 57

Spectros00pic measurements leading to kinetic
data of (5- nitro- 2- thenoyl) benzoyl peroxide
at 720 900 o o o o o o o o o o o o o o o o o 58

Spectrosc0pic measurements leading to kinetic

data of (5— nitro- 2- thenoyl) benzoyl peroxide

at 82. 17° . . . . . . . . . . . . . . . . . 59
Spectroscopic measurements leading to kinetic

data of (5- nitro- 2- thenoyl) benzoyl peroxide

at 90. 35° . . . . . . . . . . . . . 60

Kinetic data of peroxides . . . . . . . . . . . 61

vii

LIST OF FIGURES

Figure Page

1. Quantitative infrared spectra of the decom-
position of 2- -thenoyl benzoyl peroxide at
72. 90° in carbon tetrachloride, 0. 2M. in
o o o o o o o o o o 62

styrene

2. Quantitative infrared spectra of the decom-
position of 2- -thenoyl benzoyl peroxide at
82.17° in carbon tetrachloride, 0. 2M. in
O O O O O O O O O O 63

styrene

3. Quantitative infrared spectra of the decom-
position of 2-thenoyl benzoyl peroxide at
90.35° in carbon tetrachloride, 0.2M. in

64

Styrene O O O O O O O O

A. Quantitative infrared spectra of the decom-
position of 3-thenoy1 benzoyl peroxide at

72.90° in carbon tetrachloride, 0.2M. in
Styrene O 0 O O O O O I O O O O 0 65

5. Quantitative infrared spectra of the decom-
position of 3-thenoyl benzoyl peroxide at

82.17° in carbon tetrachloride, 0.2M. in
styrene . . . . . . .

6. Quantitative infrared spectra of the decom-
position of 3- -thenoy1 benzoyl peroxide at
90. 35° in carbon tetrachloride, 0. 2M. in

66

67

styrene . . . .

7. Quantitative infrared spectra of the decom-
position of (5-methyl- 2- thenoyl) benzoyl
peroxide at 72. 90° in carbon tetrachloride,

0. 2M. in styrene . . . . . 68

8. Quantitative infrared spectra of the decom-
position of (5-methyl-2-thenoy1) benzoyl
peroxide at 82.17° in carbon tetrachloride,

0.2M. in styrene . . . . . . . 69

viii

Figure

10.

11.

l2.

l3.

1”.

15.

16.

17.

LIST OF FIGURES (Continued)

Quantitative infrared spectra of the decom-
position of (5-methyl- 2-thenoy1) benzoyl
peroxide at 90. 35° in carbon tetrachloride,
0. 2M. in styrene . . . . . . . . . .

Quantitative infrared spectra of the decom—
position of (5-ethyl-2-thenoyl) benzoyl
peroxide at 72.90° in carbon tetrachloride,
0.2M. in styrene . . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5-ethyl-2-thenoyl) benzoyl
peroxide at 82.17° in carbon tetrachloride,
0.2M. in styrene . . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5-ethy1—2-thenoy1) benzoyl
peroxide at 90.35° in carbon tetrachloride,
0.2M. in styrene . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5-t-butyl-2-thenoyl) benzoyl
peroxide at 72.90° in carbon tetrachloride,
0.2M. in styrene . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5-t-butyl-2-thenoy1) benzoyl
peroxide at 82.17° in carbon tetrachloride,
0.2M, in styrene . . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5— —t-butyl- -2- thenoyl) benzoyl
peroxide at 90. 35° in carbon tetrachloride,
0. 2M. in styrene . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5-nitro-2-thenoyl) benzoyl
peroxide at 72.90° in carbon tetrachloride,
0.2M. in styrene . . . . . . . . . . . .

Quantitative infrared spectra of the decom-
position of (5- nitro- 2- thenoyl) benzoyl
peroxide at 82.17° in carbon tetrachloride,
0. 2M. in styrene . . . . . . . . . . .

ix

Page

70

71

72

73

7A

75

76

77

78

Figure

18.

19.

20.

21.

22.

23.

LIST OF FIGURES (Continued)

Page

Quantitative infrared spectra of the decom-

position of (5-nitro- 2-thenoy1) benzoyl

peroxide at 90. 35° in carbon tetrachloride,

0. 2M. in styrene . . . . . . . . . . . . . 79
Infrared spectrum of (5-methy1-2-thenoyl)

benzoyl peroxide in carbon tetrachloride. . 80
Infrared speCtrum of (5-ethy1-2-thenoy1)

benzoyl peroxide in carbon tetrachloride. . 81

Infrared spectrum of (5-t-butyl-2—thenoyl)
benzoyl peroxide in carbon tetrachloride. . 82

Infrared spectrum of (5-nitro-2-thenoyl)
benzoyl peroxide in carbon tetrachloride. . 83

Energy of activation of (5- t-buty1-2-thenoy1)
benzoyl peroxide . . . . . . 8A

._.
r...

 
 
 

INTRODUCTION AND HISTORICAL

Interest in the behavior of peroxy compounds
has been shown by those concerned with their theoretical
aspects and those interested in their industrial applica-
tions. Free radical reactions are often catalyzed by
peroxides and this has made such peroxides as cumyl per-
oxide, bis-t—Butyl peroxide, and benzoyl peroxide impor—
tant catalytic reagents.

The initial thermal reaction of the peroxide
is the unimolecular cleavage of the oxygen—oxygen bond
and first order kinetics would be expected for practically
all peroxide decompositions. This is true for the thermal
decompositions of di-alkyl peroxides, but complications
appear to interfere with the clear—cut unimolecular de-
compositions for acyl derivatives of the aromatic series.
Both Brown (1) and Erlenmeyer and Schoenauer (2) deter-
mined that the decomposition reactions of aromatic acyl
peroxides were complex in order, a higher order induced
reaction being superimposed upon the first order oxygen—
oxygen bond scission process. A study of these compli—
cations was made by Bartlett and Nozaki (3) who showed
from their data that the assumption of the previous

authors was essentially correct, and orders varying from

0.5 to 2.0 could be observed. There was also consider—
able variation in the kinetic picture as the solvent was
varied. The work of Swain, Stockmeyer and Clark (A) was
essentially responsible for isolating the unimolecular
oxygen-oxygen bond cleavage reaction from the induced de-
compositions, by introducing a free radical scavenger,
such as 3,4-dichlorostyrene or methyl methacrylate. The
addition of these inhibitors increased the decomposition
half-life of benzoyl peroxide at 80°C. by a factor of
ten, and the variability of the reaction rate in differ-
ent solvents became almost negligible. These investi-
gators (A) varied the solvent from benzene to acetophenone;
if one considers the large difference in polarity between
these solvents, it suggests the almost complete absence
of any ionic chemical species at any stOp within the de-
composition mechanism.

Later studies by Swain (A) as well as Blomquist
and Buselli (5) were directed toward an examination of
the relationship of peroxide decompositions and the
Hammett Law (6). For the substituted derivatives of ben-
zoyl peroxide, provided the substituents were located
meta- and para— with respect to the peroxide linkage,
these investigators found that the Hammett Law was fairly
well obeyed. A reaction constant rho of -0.38 indicated
that the cleavage is favored by an increase of electron

density at the reaction site. The small value of rho

-\~

2.

 

 
 

P.

'5:

also indicated that the decompositions were not strongly
influenced by the electron donating or attracting prop-
erties of the substituent in question.

The similarities between the benzenoid system
and the heteroaromatic system of thiophene are rather
striking. Thus, it was anticipated that the behavior of
the peroxides derived from either 2—thenoic or 3-thenoic
acid would show certain similarities to the benzoyl per-
oxides. Only one peroxide of this type, namely bis-(2-
thenoyl) peroxide had been prepared prior to 1959 (7);
Schuetz and Teller (8) reported the preparation and
kinetic studies of the thermal decompositions for ten
compounds; derivatives of bis-(2-thenoy1) peroxide. They
also included a study of the peroxide derived from the
unsubstituted 3-thenoic acid, as well as one unsymmetrical
compound, 5—methyl-bis(2-thenoyl) peroxide. These inves-
tigators found that for the series of symmetrical com-
pounds under investigation the Hammett equation was
followed reasonably well, a rho value of —0.AA being

obtained by a plot of sigmal plus sigma for the substi-

2
tuents involved against log k. The work of Schuetz and
Teller was extended to compounds derived from substituted
3-thenoic acids as well as additional substituted 2—thenoyl
peroxides by Schuetz, Gruen, Byrne and Brennan (9). A

total of nine new peroxides were prepared and the thermal

decomposition rates of eight of these compounds were

examined. Five of these peroxides were derivatives of
3-thenoic acid, three of 2-thenoic acid; all were symmet-
rical about the oxygen—oxygen bond. It was found that,
in general, electron donating groups accelerated decom-
positions whereas electron attractors retarded the de-
composition rates. This was especially true of the
peroxides with substituent halogens which showed the pre-
ponderance of an inductive effect over the resonance ef-
fect in these reactions. A notable exception was bis-
(5-nitro-3—thenoy1) peroxide; the nitro group seemed to
enhance the decomposition greatly, quite contrary to
expectation, which was explained by a possible reversal
of the dipole from a negative polarity toward the oxygens
to a positive charge at the central bond (10, 11). In
this series of peroxides it was also found that the
Hammett Law was generally not applicable. It should be
noted that for quite a few of the compounds studies by
these investigators an "ortho—effect" would be expected.
An attempt was made to calculate rho values for the two
compounds for which such an effect would be absent, namely
bis-(5-chloro) and bis—(5-bromo-3-thenoyl) peroxide, but
even in these cases it was found that the calculated rho
values varied from —0.087 to -0.l23. Activation energies
and entropies were calculated and found to vary from
38.1 to 20.1 kilocal. per mole for the activation ener-
gies and from -22 to +30 e.u. for the entropies of acti-

vation.

“-

.1..

.\~

:-
9 u.

C»
:.

 

.a‘

4.

 

~\b

"\

.
“a

~\~
lu‘

The present investigation is essentially con-
cerned with a study of a new series of peroxide compounds,
unsymmetrical peroxides bearing a benzene and a thiophene
ring, and being substituted, if at all, in the hetero-
cyclic system only. It seemed of interest and value to
study this series of compounds from several points of
View, as peroxides intermediate between the bis-(benzoyl)
peroxides and the symmetrical peroxides in the thiOphene
series; they would afford an Opportunity to study the
effects on the decomposition rates due to the presence
of substituents in only one of the two ring systems
present. Leffler (12) carried out a study on unsymmetri-
cal peroxides in the benzenoid series, but had employed
different reaction conditions favoring an ionic mechanism.
As mentioned previously, the only unsymmetrical peroxide
studies to this point in the thiOphene series was 5-methyl-
bis(2-thenoy1) peroxide (8). The investigation reported
here, it is felt, is therefore unique, as it involves,
for the first time, a carbocylic aromatic as well as a
hetero-aromatic system studied under conditions favoring
free radical decompositions which are homolytic at the
oxygen-oxygen bond. A total of eight new peroxides were
prepared and the kinetics of decomposition of six of
these compounds were studied. These compounds were chosen
as they all bear either no substituent or substituents in

the 5-position of the heterocylic ring. For comparison

3-thenoyl benzoyl peroxide was included. Three of the
substitutents chosen were typical electron releasers:
methyl, ethyl, and t—butyl; one, the nitro group, was
a typical electron attractor. Infrared spectroscopy
was employed for the analysis in this series of com-
pounds (9), an I.R.5 Beckmann SpectrOphotometer being
employed; the solvent was M.C.B. Spectroquality carbon
tetrachloride. The solutions were kept exactly at
0.1000 molar concentration, in the presence of 0.2
molar styrene as a free-radical scavenger. Strict
precautions were observed to keep the ampoules free
of dirt, dust and oxygen, and a constant temperature
bath employed was set up in a dark room, to avoid com-
plications due to photochemical reactions of any kind.
First order kinetics were found to be obeyed
by all compounds under investigation. It was felt that
the use of a larger temperature span than that employed
in previous investigations of peroxide decompositions
was preferable (8, 9). The total temperature span was
extended to eighteen degrees, with a difference of about
nine degrees being used between kinetic determinations.
Duplicate determinations were employed for each tempera-
ture. Activation energies and entropies were calculated,
the former by a plot of the logarithm of the rate con-
stant against the reciprocal of the absolute temperature,

the latter by the use of the Eyring equation (13).

Slopes were determined from the kinetic plots by the
method of least squares, employing a CDC 3600 computer
at the Michigan State University computer center. The
author is greatful for the help of Mrs. Norma Ray of

that office and her unselfish COOperation.

EXPERIMENTAL

Chemical Reagents

 

The carbon tetrachloride used as a solvent in
the kinetic determinations was MCB Spectrograde CX A15.
The 3-bromothiophene was purchased from the Aldrich
Chemical Corporation, their White Label product.

The 5-t-buty1-2-acety1thiophene was donated as
a sample by the Pennsalt Corporation; 2—furoic acid was
an Eastman Kodak product, reagent grade. The writer is
indebted to Dr. Fred M. Gruen of Olivet College for
samples of 5-methyl-2—thenoic acid and 3-methyl—2-thenoic
acid.

The styrene used as a free radical scavenger
was Eastman Kodak White Label material, stabilized with
t-butyl catechol. It was distilled in vacuo and stored

in a refrigerator, in the dark, without inhibitor.

Syntheses

 

2-Acety1thiophene

 

The method of Hartough and Kosak (1A) was em-
ployed in the preparation of this compound. A solution
of 252 g. (3.0 moles) of thiophene and 117 g. (1.1 mole)
of acetic anhydride was stirred and heated to 70° in a

one-liter,three—necked flask. Ten grams of orthOphosphoric

8

-\u

4 s

acid were then added cautiously from a drOpping funnel
during fifteen minutes. The temperature rose to 87-88°
during the addition of the acid and the mixture was im-
mersed in an ice-bath to prevent further rise in tempera-
ture. After completion of the addition the mixture was
refluxed at 95-96° for two hours, during which time it
turned dark in color. The mixture was then allowed to
cool, water (200 ml.) was added and the aqueous mixture
stirred for thirty minutes. The organic layer was sepa-
rated, washed several times with 200 ml. portions of 10%
sodium corbonate solution and then with water. The mix—
ture was distilled at atmospheric pressure to remove the
thiophene—water azeotrOpe and the residue was distilled
in vacuo through a 6 inch Vigreux column to obtain 103 g.
(0.82 mole, 74%) of 2-acety1thiOphene, b.p. 79—81°/6 mm.

Literature value (14): 77°/4 mm.

2-Thenoic Acid

 

In a four-liter beaker were placed 440 g. (11
moles) of sodium hydroxide pellets in 600 ml. of water
and 2,500 g. of ice. The beaker was tared and 332 g.
(4.53 moles) of chlorine gas were passed from a cylinder
into the basic solution. The hypochlorite solution was
heated to 60° and transferred to a five-liter three-necked
standard taper flask fitted with mechanical stirrer,

drOpping funnel and reflux condenser. AcetylthiOphene

 

.x.

 

-.

~-

 

 

. .

‘
‘

10

(73.0 g., 0.58 mole) was added dropwise to the hypochlorite
solution. During the addition of the ketone, the tempera-
ture of the reaction mixture rose to 67—68°, and was main-
tained by means of a cooling bath. Rapid refluxing due to
the evolution of chloroform could be observed. The mix—
ture was stirred and allowed to cool. A solution of 100 g.
of sodium bisulfite in 200 m1. of water was added to de-
stroy the hypochlorite. Careful acidification under cool-
ing gave a heavy white precipitate. After standing
overnight, the solid was recovered by filtration. Re-
crystallization from hot water gave white needles (0.52
moles, 67 g., 90.4%), melting at 127-218°. Literature

value: (15) l28-l29°.

3-Cyanothiophene

 

A mixture of 3-bromothiophene (115.2 g., 0.71
mole), cuprous cyanide (80 g.) and quinoline (Eastman
Technical grade) (480 ml.) was heated under reflux in a
two-liter, three-necked standard taper flask for three
hours. The color of the reaction mixture changed from a
dark green to a yellowish brown in an hour under reflux.
After reflux the mixture was allowed to cool and then 400
ml. of liquid were removed by vacuum distillation, during
which the temperature of the residual liquid reached approxi-
marely 180°. The distillation was carefully acidified with
1:1 hydrochloric acid and set aside overnight in a re—

frigerator. It was then extracted with ether and washed

 

or

w -

CA

a-

a»,

in

e:

'v

11

twice with 6 N. hydrochloric acid and finally with water.
After having been dried over anhydrous calcium chloride,
the solvent was removed from the ether extract and the
residual oil was vacuum distilled to yield: 74 g. (0.679

mole, 96.1%) of the crude product.

3-Thenoic Acid

 

The crude 3-cyanothiOphene was placed in a three-
liter, three—necked standard—taper flask and 1,480 ml. of
concentrated hydrochloric acid were added. The mixture
was then refluxed for 3.5 hours. Following this the mix-
ture was cooled very slowly to allow the slow crystalli-
zation of the product. The product was recovered by
filtration and extraction of the mother liquor with ether
to yield a total of 79.0 g. (0.616 mole, 90.8%) of 3-
thenoic acid, mp. 136-137°. Literature value (17):

mp. 137—138°.

2-EthylthiQphene

Using the experimental procedure of King and
Nord (18) a mixture of 100 g.(0.79 mole) of 2-acetylthio-
phene, 155.1 ml. of 85% hydrazine hydrate and 617.1 ml.
of ethylene glycol was stirred and heated to 170° to
remove excess hydrazine and water. About 120 ml. of dis-
tillate was collected, and the residue was allowed to
stand overnight protected from moisture by means of a

calcium chloride tube. The distilling head was replaced

P'

 

ft!

 

||J

M!

I

 

 

12

by a reflux condenser and 55.4 g. (0.99 mole) of potassium
hydroxide pellets were added. The stirred mixture was
heated to a temperature of 120° when the evolution of
nitrogen began. The temperature was maintained at 120-
140° for approximately two hours after which time the
mixture was allowed to cool; it was observed that the
solution had changed to a two-phase liquid mixture during
nitrogen evolution.

After standing overnight the reaction mixture
was distilled through a six-inch Vigreux column until
the vapor temperature had reached 140°. The distillate
was extracted twice with ether, the ether solution washed
once with 1:1 hydrochloric acid and twice with water and
dried over anhydrous calcium chloride. The ether was re-
moved on a steam-bath and the product distilled at stmos-
pheric pressure to yield 76 g. (0.68 mole, 86%) of product

boiling at 133-135°. Literature value (19): b.p. l32-134°.

5-Ethyl—2-Acetylthiophene

The apparatus and general method described for
the preparation of 2-acetylthiophene (14) was used to pre—
pare this compound. Orthophosphoric acid (5 g.) was added
at room temperature to a well stirred mixture of 56 g.
(0.5 mole) of 2-ethylthiophene and 55 g. (0.540 mole) of
acetic anhydride. During the addition of the catalyst the

temperature rose spontaneously to 37-38°. The mixture

II

(J

13

was then heated with vigorous stirring to l35-l40°, its
reflux temperature. The mixture was then refluxed for
three hours. After cooling to room temperature, water
was added to the mixture and it was stirred for an addi-
tional fifteen minutes. The organic layer was separated,
washed with 10% sodium carbonate to basic reaction and
then twice with water. The brown oil was dried over an-
hydrous magnesium sulfate and distilled in vacuo to yield,
after a small forerun, 47.6 g. (0.317 mole, 58.7%) of

water-clear liquid, boiling at 100°/10 mm.

5-Ethyl-2-Thenoic Acid

 

Using the experimental procedure described for
the preparation of 2-thenoic acid (15),47.6 g. (0.317 mole)
of 5—ethyl-2-acetylthiophene were used to prepare this
acid. The 5-ethyl-2—acetylthiophene was added drOpwise
to a solution of sodium hypochlorite prepared from 132 g.
(3.30 moles) of sodium hydroxide, 94.5 g. (1.35 moles) of
chlorine and 800 g. of ice. The initial temperature of
the reaction mixture was 52°, but it had to be raised to
78-80° before the reaction commenced, as evidence by re-
flux (chloroform). The reaction temperature was controlled
at 75-78° by means of alternate heating and cooling. The
temperature was maintained for two hours, and then the mix-
ture was cooled to room temperature. A solution of 35 g.

of sodium bisulfite in 100 m1. of water was added. The

.A

tr".

FIB

Afi"

uni"

. J .< - rs.
. y - ~ a
‘a n A. v 94*
ul , . -~

.. .. .. . .C

r. a n ~s - g u“
u‘ “.5 n v V a
'1‘ .I u ~ h n-

!\ fl-\
. a . w
1‘ a:
«a C»
u. .Ph

 

14

solution was tested with potassium iodide-starch paper to
assure complete reduction of the hypochlorite. The re-
action mixture was transferred to a four liter beaker and
acidified cautiously with concentrated hydrochloric acid,
yielding a white precipitate. Yield: 40.7 g. (0.269 mole,
84.8%) of product melting at 67-70°. Literature value

(20): 71°.

5-t-Butyl-2-Thenoic Acid

 

Using the experimental procedure described pre-
viously for the preparation of 2-thenoic acid (21), 54.6 g.
(0.30 mole) of 5-t—butyl-2-acetylthiophene (supplied as a
sample by the Pennsalt Corporation) were added drOpwise
during approximately 30 minutes to a solution of sodium
hypochlorite. The latter was prepared from 132 g. (3.30
moles) of sodium hydroxide, 96 g. (1.35 moles) of chlorine
and 800 g. of ice. The temperature of the mixture was
maintained at 50-55° during the addition of the ketone.
Following the addition of the ketone the mixture was
heated to 75°. At this point the temperature began to
rise rapidly, indicating that the reaction had been ini-
tiated. To control the exothermic initial reaction it
was necessary to apply' alternate cooling and heating
to keep the reaction temperature in the range of 75-85°.
During the reaction the color of the solution changed

from a foggy yellow to a clear yellow and finally violent

T.

.-v

I u
A-v

‘-

 

/‘

\

l5

bubbling due to the evolution of chloroform could be ob-
served. The reaction mixture was set aside overnight

and a solution of 30 g. of sodium bisulfite in 100 m1.

of water was added. The mixture was extracted with ether
to remove neutral materials. The aqueous layer was then
transferred to a three-liter, three-necked flask fitted with
a stirrer and 500 ml. of ethyl ether were added under
stirring. The mixture was carefully acidified with con-
centrated hydrochloric acid. After separation of the
ether extract, the water layer was again extracted with
ether. The combined ether extracts were dried over anhy-
drous magnesium sulfate, and the ether was removed leaving
an orange-white liquid which solidified after being trans-
ferred to a beaker. Recrystallization of the material
from ligroin (b.p. 90—120°) gave 18 g. (9.1 mole, 33%)

of a crystalline material, melting at 124-125°. Litera-

ture value (21): 128-128.5°.

2—Thenal

The method of Campaigne and Archer (22) was em-
ployed in the preparation of this aldehyde. In a liter,
three—neckedflaskffitted with21mechanical stirrer, reflux
condenser and dropping funnel were placed 84 g. (1.0 mole)
of thiophene and 92 g. (1.28 moles) of N,N-dimethylforma-
mide and the mixture was cooled by immersion in an ice-
bath. To the stirred mixture there was added 192 g.

(1.24 moles) of phosphorus oxychloride during two hours.

16

During the addition of the inorganic chloride the reaction
mixture underwent a change from clear white to canary
yellow. Following the addition of the phosphorus oxychlo-
ride the mixture was refluxed for an hour and a half on a
steam bath during which it underwent further coloration
changes from yellow to reddish-black. The reaction mix-
ture was then cooled, partially neutralized with 10%
sodium hydroxide solution and then completely neutralized
by the addition of solid sodium carbonate. The mixture
was next extracted with ether, the ether extract was
washed with water and set aside in contact with anhydrous
sodium sulfate overnight. The ether was removed on a
steam bath leaving a reddish black oily residue. The
latter was distilled in vacuo using a six-inch Vigreux
column and the fraction distilling at 82-84°/20 mm. was
collected as product. The yield was 73.5 g. (0.654 mole,

65.4%). Literature value (22): 44-45°/lmm.

5-Nitro-2-Thenal

The experimental method of Buu H01 (23) was em-
polyed for the preparation of this aldehyde. A 250 m1.
flask was equipped with a mechanical stirrer, dropping
funnel, and Allihn condenser. The flask was cooled by
immersion in an ice-bath. Into the flask was placed a
solution of 26 g. (0.232 mole) of 2-thenal in 50 g.

(0.490 mole) of acetic anhydride. To the cold aldehyde

17

solution there was added a mixture of 50 g. of glacial
acetic acid and 19.8 g. of fuming nitric acid (sp.g. 1.49)
during a half hour in which time the reaction mixture
changed from a light brownish red to a clear canary yellow.
Care was taken to keep the reaction temperature below 0°
during the entire experiment. Following addition of the
nitrating mixture the solution was stirred at 0° for an
additional hour and a half and then poured into approxi-
mately 200 ml. of a crushed ice slurry. Initially the
mixture became cloudy and a reddish oil separated from
solution. This,after brief stirring,solidified to a cry—
stalline solid. This was removed by filtration and

washed several times with distilled water. The filtrate
which had a turbid yellow-green color was again poured
into water and the additional product was recovered by
filtration. The combined solid product was air-dried for
several hours and then recrystallized from 95% ethanol

by dissolving it in ethanol, concentrating the solution

on a steam-bath, and allowing the concentrated solution

to stand overnight. The pale—brown crystalline product
was recovered by filtration. The yield was 29.8 g.

(0.189 mole, 82%). The melting point was 72°. Literature

value (23): 77°-

5-Nitro-2-Thenoic Acid

 

The experimental procedure was adapted from the

general method described by Migridichian (24). Into a

18

two-liter,three-necked flask fitted with a stirrer, Allihn
condenser, thermometer and dropping funnel was introduced
a mixture of 400 m1. of water and 400 m1. of 95% ethanol
containing 18.8 g. (0.12 mole) of 5-nitro-2-thenal. A
Ml8g;(0.24 mole) quantity of silver nitrate was then

added to the reaction mixture, at which point the mixture
had a slight pale brown—yellow color. A solution of 19.2 g.
(0.48 mole) of sodium hydroxide in 400 m1. of water was
then placed in the dropping funnel and allowed to drip
slowly into the well—stirred mixture during a half hour
while holding the reaction mixture below 50°. Following
addition of the base the mixture was stirred for fifteen
minutes, then cooled in an ice-bath for thirty minutes

and filtered. The large cake of silver remaining on the
filter was washed several times with hot water and the
washings were added to the filtrate. As the filtrate was
still turbid, it was refiltered several times through a
finer filter by using a piece of filter paper placed in-
side the "coarse grade" sintered glass funnel. After
several filtrations the filtrate had a slight yellow-green
color, but was clear. Its total volume was approximately
1,500 ml. The filtrate was concentrated until the volume
had been reduced to 500 ml. and 500 m1. of ethyl ether
were added. The mixture was carefully acidified with con-
centrated hydrochloric acid. A cloudy white material pre-

cipitated, but quickly dissolved in the ether layer. The

l9

ether layer was separated and the aqueous solution was
extracted with several portions of ether. The ether
extracts were combined and dried over anhydrous magne-

sium sulfate. The ether was removed on a steam bath,
leaving a yellow—brown solid. During the evaporation

of the solvent a brown gas was observed indicating the
presence of residual nitric acid. The solid was re-
crystallized from hot water to obtain pure product in

the form of yellow needles, melting at 158-159°. Literature

value (25): 158°. The yield was 11.0 g. (0.064 mole,53%).

Preparation of Acid Chlorides

 

The thenoyl chlorides used in this work were
prepared by reaction of the corresponding carboxylic
acids with thionyl chloride; their properties are sum-

marized in Table 1. A typical preparation follows:

2—Thenoy1 Chloride (26)

 

In a 100 m1. flask fitted with an Allihn con-
denser and heating mantle, there were placed 12.8 g.
(0.1 mole) of 2-thenoic acid and 46.0 g. (0.39 mole) of
thionyl chloride. The mixture was heated under reflux
for ten hours, during which it became a clear orange
colored solution. After cooling,the excess thionyl
chloride was removed by distillation at atmospheric

pressure using an eight-inch Vigreux column.

20

 

Ammv .es m.a\m: mm Hsopsmum

 

Ammv .es m.m\wHHI:HH m.mm meHeOHso Hsoemeeumuospfizum
Ammv .ss m.:\mHH :.Hw mentoaso HmoemeBINIHspsm-pum
empeoamm poz .ss m\mmusm s.mm weapoaeo Hmoemsenmnasnpmnm
Ammo .ss H.m\mwusm H.ss mentoano HsocmeeumnfisemeIm

Ame .ee mxmmuam mm mefieoaeo Hsoemeeumuasepmznm
Asav .es o.mnm.s\ms Hm mefieofleo Hmoemneum
Asmv .se m.a\m.mmnm.mm mm meHAOHeo Hsoemeenm
mwmmmmwmmm oo .m.m hemopmm sassy mefieoaeo efioa

 

 

.mmefieoaeo efioa we» eo consummamem .H mfinwe

21

The residual dark colored oil was distilled lg
yaggg, yielding 14.1 g. (0.095 mole, 95%) of clear color-
less liquid which solidified immediately on immersion of
the receiver in a dry-ice isopropanol bath. The boiling
point was 58.5—59.5°/l.5 mm. (McLeod gauge). The distil—
lation of this product was carried out in a micro apparatus
using a fraction cutter. The product was stored in the
dark at 0° and protected from moisture by a calcium

chloride drying tube. Literature value (27): 92°/18 mm.

Sodium Perbenzoate

 

The material was prepared by the experimental
procedure originally reported by Braun (28). In a 500 ml.
Erlenmeyer flask, cooled by immersion in an ice-salt bath,
and fitted with a calcium chloride drying tube there were
placed 100 ml. of absolute methanol in which 5.2 g. (0.22 g.
atom) of sodium metal had been dissolved. A 50 g. (0.21
mole) quantity of benzoyl peroxide was dissolved in 200 ml.
of pure chloroform and the solution chilled by immersion
in an ice-salt bath. The benzoyl peroxide-chloroform
solution was then added quickly to the sodium methoxide
solution and the resulting mixture was vigorously stirred
for four to five minutes while immersed in an ice-salt
bath. The mixture turned turbid and after several minutes
a (:urdy, cheese-like solid had formed. The mixture was

truansferred to a two-liter separatory funnel and the

22

sodium perbenzoate was extracted with 500 ml. of ice-cold
water. The aqueous extract was washed with two 100 m1.
portions of chloroform and used directly in the preparation

of the unsymmetrical peroxides.

2-Thenoyl Benzoyl Peroxide

 

The aqueous sodium perbenzoate solution was
maintained at -5 to 0° by immersion in an ice-salt bath
and then introduced into a 500 m1., three-necked, standard
taper flask fitted with a mechanical stirrer, Allihn con-
denser and dropping funnel. The flask was chilled by im-
mersion in an ice-salt bath. A solution containing 14.1 g.
(0.095 mole) of 2-thenoyl chloride in 50 ml. of dry cyclo-
hexane was added dropwise during fifteen minutes to the
perbenzoate solution. Precipitation of a white material
was observed almost immediately. The reaction mixture
was stirred vigorously for an additional hour and the
solid product was recovered by filtration on a sintered
glass funnel. The colorless, fluffy, extremely hydro-
phobic peroxide was washed several times with 100 m1.
portions of ice-cold water and dried in a vacuum disic—
cator at 0°, while being protected from light. The yield
of product was 20.9 g. (0.084 mole, 88.4%, based on 2—
thenoyl chloride), which melted sharply at 92.0-92.5°.
After melting,the liquid turned red, but did not detonate.
Calculated for Cl2H8O4S: C, 58.06; H, 3.23; S, 12.90.

Found: C, 57.44; H, 3.20; S, 12.84.

23

3—Thenoy1 Benzoyl Peroxide

 

The sodium perbenzoate solution was introduced
into a 500 m1., three—necked, standard-taper flask, fitted
with a mechanical stirrer, Allihn condenser, and dropping
funnel and cooled to -5tx>0° by immersion in an ice—bath.
To the vigorously stirred solution was added a solution
containing 12.0 g. (0.081 mole) of 3—thenoy1 chloride in
50 m1. of dry cyclohexane. Within minutes a white solid
formed which had a cheese-like appearance. The reaction
product was stirred at -5to 0° for an additional hour,
after which the solid product was recovered by filtration
on a sintered glass funnel. The white, fluffy, hydropho-
bic solid was washed several times with 100 ml. portions
of ice-cold water. The yield was 18.3 g. (0.073 mole,
90.1% based on 3-thenoyl chloride) of a snow-white solid
melting sharply at 101-lOl.5°. The peroxide, after melt-
ing, did not detonate, but turned red in color. The prod-
uct was placed in a vacuum desiccator, evacuated for two
hours and then stored in a refrigerator in the dark a 0°.
Calculated for Cl2H8O4S: C, 58.06; H, 3.23; S, 12.90.

Found: c, 57.90; H, 3.24; 3, 12.98.

(3-Methyl-2—Thenoyl) Benzoyl Peroxide

 

The sodium perbenzoate solution was placed in a
500 m1., three-necked, standard taper flask fitted with a re-

flux condenser, stirrer and dropping funnel. The flask

 

24

was immersed in a dry-ice is0propanol bath in order to
maintain the temperature at —5 to 0°. A solution con-
taining 16 g. (0.106 mole) of 3-methy1-2-thenoy1 chloride
in 50 m1. dry cyclohexane was added dropwise to the re-
action mixture. The mixture was stirred for an additional
hour and the precipitated white solid was recovered by
filtration_and washed with several portions of ice-cold
water. It was dried in vacuo, yielding 15.0 g. (0.056
mole, 53% based on 3-methyl-2-thenoyl chloride) of prod-
uct, melting at 49.5-50.0°. The white material, upon
melting, did not detonate or turn color.

Calculated for C 0048: C, 59.53; H, 3.84; S, 12.22.

13H1
Found: C, 59.44; H, 3.84; S, 12.24.

(5-Methyl-2-Thenoyl) Benzoyl Peroxide

The sodium perbenzoate solution prepared as in-
dicated previously, was introduced into a 500 m1., three-
necked, round bottomed flask, fitted with a mechanical
stirrer, Allihn condenser, and dropping funnel. The flask
was cooled by immersion in an ice-bath and 3.9 g. (0.027
mole) of 5-methyl-2-thenoyl chloride dissolved in 50 ml.
of dry cyclohexane was added to the perbonzoate solution
through the dropping funnel during one hour under vigorous
stirring. Precipitation of the product initiated almost im-
mediately. The entire system had been kept at -5tx>0° during

the whole experiment. The solid was recovered by filtration

25

and washed several times with cold water. The yield of
peroxide was 4.25 g. (0.016 mole, 59.2%) of a colorless
solid, which melted at 82-83°. A small portion of the
product held in a Bunsen flame acted in a manner typical
of this type of peroxide. The solid turned deep-red in
color on melting, but did not detonate.

Calculated for: 0048: C, 59.53; H, 3.84; S, 12.22.

Cl3Hl
Found: C, 59.49; H, 3.79; S, 11.95.

(5-Ethy1-2-Thenoy1) Benzoyl Peroxide

 

A method analogous to that described for the
synthesiscfi‘(5-methyl-2—thenoyl) benzoyl peroxide was
used to prepare this compound. In the apparatus described
above there was added dropwise 18.1 g. (0.103 mole) of
5-ethy1—2-thenoyl chloride in 50 m1. of dry cyclohexane
to the perbenzoate solution. The reaction mixture became
turbid, but no precipitation occurred. The mixture was
stirred for one and a half hours while immersed in an ice-
salt bath. The cyclohexane layer was separated and reduced
to about one half of its volume by removal of solvent in
an air stream. The residual material was set aside in a
refrigerator overnight; some crystallization of the prod-
uct from solution was observed the following morning.
However, when a drop of the mother liquid was placed in
the flame of a Bunsen burner, a large flash was observed,

indicating the presence of peroxide in solution. The

26

solution was then placed in a dry-ice is0propanol bath
where a yellowish solid crystallized from solution. The
solid was extracted into petroleum ether (b.p. 30-60°)

and set aside overnight at 0° in the dark to allow crystal-
lization of the product to occur. The yield of peroxide
obtained was 15.5 g. (0.056 mole, 54.4%) of a lightly
orange colored crystalline solid, melting at 52-53°. 0n
melting the product turned deep red in color and decom-
posed at 100°. After drying the peroxide in vacuo for
several days at 0°, an analytical sample was obtained.
Calculated for C14H12O4S: C, 60.84; H, 4.37; S, 11.62.

Found: C, 59.93; H, 4.33; S, 11.74.

(5-t-Buty1-2-Thenoyl) Benzoyl Peroxide

Using the apparatus described above,there was
added during an hour 8.25 g. (0.0407 mole) of 5-t-butyl-
2-thenoyl chloride in 50 ml. dry cyclohexane to the pre-
cooled and vigorously stirred sodium perbenzoate solution.
During the addition of the acid chloride no precipitation
of product occurred. The reaction mixture was stirred
for an additional hour, after which time the cyclohexane
layer was separated and its volume was reduced to about
25 ml. by evaporation of the solvent in an air stream.
The residual liquid was set aside overnight in the re-
frigerator, to permit crystallization of the peroxide

‘product. This was recovered by filtration, washed with

27

cold water and dried for several hours in a vacuum desic-
cator under reduced pressure. The yield of pure product
was 3.7 g. (0.012 mole, 29.7%) of yellow colored crystals
melting at 50°. Identification of the peroxide was con-
firmed by means of its infrared spectrum (Beckman IR # 5).
When a small quantity of the peroxide was held in a Bunsen
flame, it behaved typically. After melting,the compound
turned red and decomposed above 80°. The compound was
highly hydrOphobic.

Calculated for Cl6H16O4S: C, 63.13; H, 5.30; S, 10.55.

Found: c, 62.70; H, 5.43; 3, 10.98.

(5-Nitro-2-Thenoyl) Benzoyl Peroxide

The sodium perbenzoate solution was placed in a
500 m1. flask as described above. A solution containing
7.15 g. (0.040 mole) of 5—nitro-2—thenoyl chloride in
100 ml. of dry cyclohexane was added dropwise during one
hour to the vigorously stirred, prechilled perbenzoate
solution. A beige colored solid precipitated from solu-
tion during the addition of the acid chloride. The mix-
ture was stirred during an additional hour and the rather
hydrophobic, beige colored solid was recovered by filtra-
tion and washed several times with 200 m1. portions of
ice water. The solid was dried in a vacuum disiccator
overnight in the dark. The solid melted sharply at
82.5-83°. The yield of pure product was 7.8 g. (0.026

mOIe, 65%). After melting the solid turned red and detonated.

28

.mHocHHHH .onoxm .mmHHOpMLoan .nompOHoaz an omEhomng mommamc< ex
.oooooneooo: modHoo weHoHoe HH< *

 

 

Hmousom
OH.O Oe.O OH.OH mO.OH Om.m HO.N OO.OO OH.OH O.mO-m.mO me szOHONHO HHOoooneum
IonOqumv
HzoNcmm
I- u- . . . . . . s OH OH HHOoeoeeum
OO OH mm OH m: m om O OH NO MH me Om Om m o m O -HOOomuoumv
Hmoucmm
nu I- . . . . . . I O OH OH HHOoeoneum
Os HH NO HH mm O em O mm mm Om OO mm mm HO O O O O -Hsnomumv
Hmoucom
I- u- . . . . . . O OH mH HHHoeoneum
mm HH mm OH mg O HO O O: mm mm mm MO mm O O O O -Hseoozumv
Hzoscmm
u- I- OO.NH OO.mH Om.m mm.m OO.sm OO.Om m.HOHuO.HOH OO mOoOmmHO Hsoeoneum
Hmomcmm
I- I- OO.NH OO.NH Om.m mm.m Oe.sm O0.0m m.mOuO.mO OO mOOOmmHO Hsoeoneum
.d ON .d 03 H OH d 00 0N .A .d
0 ET. 0 9n 0 BK 0 BB 0. I. O
n mm m mam. m mm“. m mm. e m. w
W . o p . u. D . 0 he . o x p n meonpom
H m. .1 w .. m
u u a.

 

 

.Umnmaopm mmUHNOHom .m mHQMB

29

Calculated for Cl2H706NS:
C, 49.15; H, 2.41; N, 4.78; S, 10.93.

Found: C, 48.86; H, 2.28; N, 4.79; S, 10.79.

2-Furoy1 Benzoyl Peroxide

 

The aqueous perbenzoate solution was maintained
at -5tx)0° by immersion in an ice-salt bath and intro-
duced into a 500 m1., three—necked, standard-taper flask
fitted with a mechanical stirrer, reflux condenser and
dropping funnel. Eleven grams (0.083 mole) of furoyl
chloride dissolved in 50 ml. of dry cyclohexane was added
dropwise to the sodium perbenzoate solution. The mixture
was stirred at 0° for an additional hour. The organic
layer was sepatated and filtered. A white solid material
was isolated. The solid was washed with ice-cold water
and dried in a vacuum disiccator. The yield was 5.4 g.
(0.023 mole, 20.8%, based on furoyl chloride) melting
sharply at 57.5-58°. A small sample, dropped into a
Bunsen flame, gave a typical burst of flame. After drying,
the material had a powdery appearance and was snowy-white.
Calculated for C12H8O5: C, 62.07; H, 3.42.

Found: C, 61.96; H, 3.58.

Kinetic Determinations

 

A typical kinetic determination is described,

(2-thenoyl-benzoyl peroxide) at 72.90°.

30

A 0.6231 g. (0.1000 mole) quantity of 2—thenoyl
benzoyl peroxide was weighed on a single pan (Mettler)
balance and transferred to a 25 ml. volumetric flask. The
solution was made up to volume using carbon tetrachloride
(MCB Spectroquality CX 415), which contained sufficient
styrene to make it 0.2 molar in concentration. Samples,
0.4 ml. in volume, were introduced into ampoules which
were then cooled in dry ice. After flushing each ampoule
with pure dry nitrogen (prewashed with concentrated sul-
furic acid and dried with sodium hydroxide pellets) the
ampoules were sealed with a gas-oxygen torch and trans-
ferred to a constant temperature bath (temp. i0.05°).
Duplicate samples were removed at each temperature deter-
mination. A "zero-time" of three minutes was assumed
sufficient for the samples to reach thermal equilibrium
with the bath. The initial duplicate samples were re-
moved at this point, designated zero time; samples were
removed at three-hour intervals thereafter. Each set of
samples was quenched immediately by immersion in an ice-
bath and the adherent mineral oil from the bath was washed
off with petroleum ether (b.p. 30-60°). The samples were
then stored in dry ice until analyzed in the Beckman
I.R. 5. The infrared region from 5.5 to 6.1 microns was
scanned to determine the peroxide concentration. A

total of six duplicate samples were removed in each

31

determination. As a three hour interval was kept between
removals of samples, the total time span investigated for

the temperature of 72.90° was fifteen hours.

RESULTS AND DISCUSSION

The rate constants, half lives, frequency fac-
tors, energies and entropies of activation, calculated
from the decomposition kinetic determinations of the per-
oxides studied in the course of this investigation are
summarized in Table 22. It can be seen from this data
that all the peroxides carrying substituents decompose
at a rate greater than the unsubstituted parent compounds,
regardless of the electron attracting or repelling charac-
ter of the substituent. The unique structural feature of
this series of peroxides compared with those investigated
previously (9, 26) is that here there are two different
ring systems in the same peroxide (benzenoid as well as
hetero-aromatic), and additionally there is only a single
substituent in one of the rings (the hetero-aromatic).
This intrinsic difference between these unsymmetrical
peroxides and their symmetrical counterparts (benzenoid
as well as heterocyclic) suggests that the increase in
reaction rate is in some way related to the shift of
electrons in either direction from the centrally located
oxygen to oxygen peroxide bond. It can also be noted
from the data in Table 22 that the increase in the decom-

position rate due to the substitution of either alkyl

32

33

groups or the nitro group is relatively small in magni—
tude; as the data show, the ratio between the rate con-
stant of the substituted compound and the k factor of
the parent peroxide never exceeds the value of two at
any particular reaction temperature. The difference in
reaction rates for the symmetrical series of peroxides
are more pronounced (9, 26). This may be due to the
fact that the unsymmetrical peroxides carry only one
substituent, whereas the symmetrical compounds are sub-
stituted in each ring system. It appears that for the
case of the symmetrical peroxides there is either an
accumulation of electrons, if the substituent is electron
repelling at the central linkage, or a decrease of elec-
tron density at the same bond, if the group is electron
attracting (10). For the compounds discussed in the
present work there is, due to their unsymmetrical nature,
a shift of electrons in either direction of the central
oxygen-oxygen linkage. Another interesting fact shown
by the data is the striking regularity in the increase
of the rate conStant from temperature to temperature with
all compounds. The rate constant is approximately tripled
by a temperature increase of about nine degrees throughout
the series, with the possible exception of the nitro de-
rivative.

The fact that the influence of the substituents
on the rate is practically independent of the electronic

character of the group in question may be reasonably

34

accounted for on the basis of steric considerations.
Since there is an increase in the rate of the peroxide
decomposition due to the presence of substituents, a
case of "steric assistance" (29) may exist. The size

of the nitro substituent is comparable to that of the
methyl grOUp (30), and the data show that the energies
of activation and the entropies of activation in this
series are practically the same. As a decrease in the
entropy parameter would lead to a decrease in reaction
rate, the observed rate enhancement must be due to a
decrease in energy of activation. It can be seen from
the data that both the energy and entrOpy of activation
decrease in going from the unsubstituted peroxides to
those bearing the various types of substituents. In
another series of free radical decompositions, previously
reported by Bartlett (31), it was observed that the en-
tropies of activation were decreasing with increasing
resonance stabilization of the free radicals forming in
the decompositions. There is a possibility that this
resonance effect is here superimposed upon the steric
assistance effect discussed. It should also be noted
that the ethyl substituent should be capable of higher
resonance stabilization (hyperconjugation) than is the
t-butyl group. This may be responsible for the relatively
low value of the entrOpy cfi‘ activation for the ethyl

derivative in the series of compounds examined here.

35

Another reason for the extreme values of the
activation parameters for the ethyl derivative may be
the increased possibility of varying conformations in
the linearly shaped ethyl group as compared to the more
spherical methyl- and t—butyl substituents.

In Table 3 a comparison has been made between
some of the symmetrical (both benzoyl, and 2-thenoyl)
peroxides and the unsymmetrical "mixed" compounds studied
in the present work. Rate constants have been corrected
to a temperature of 80° by means of the integrated
Arrhenius equation (32).

The energies and entropies of activation are
also given for comparison in Table 3. The most striking
fact of the data shown in the table is the small differ-
ences in magnitude of the entropy of activation values
between the unsymmetrical thenoyl—benzoyl peroxides and
the derivatives of bis-(2-thenoy1) peroxide on one hand,
and the striking difference in magnitude of these values
between the two series and the derivatives of benzoyl
peroxide. This strongly suggests that the hetero-atom
(sulfur) leads to the high entropy of activation values
for the two series containing this hetero-atom. It may
be the close proximity of the sulfur atom to the acyl
peroxide linkage imposes additional restraint on the
peroxides, which is released in their change toward the

transition state; this may well lead to entrOpy of

36

 

 

Om.OH O.Hm me.m Hmoueom HHHocoeeumuoHOqumv
m.: m.mm ow.m AHmoscmmIOHsz|QvumHm
OH.O m.Hm sm.m Hmoneom HHso:oneumuHOoomupumv
HO.HH m.Om em.: AHsoeoneumuHOOomuoumOumHm
Hm.OH O.Hm OO.m Hmondom HHOodoneumuHsneozumv
mO.HH m.Om no.3 HHHoeoneumuHHnooz-mvumHm
m.O m.Om mm.m HHHoNcomuHHnooz-ovumHm
Om.mH O.mm mm.m HHoneom HOoeoee
mm.OH m.mm m:.m Homv AHzoconelmvlmHm
m.: N.Om mm.N Amv AH%ONC®mIMHm
.s.m AH mHoE .Hmoxv
COHpm>Hpo¢ . I A 1.:HEV OH x x meonpmm .UCSOdEoo
no adoppcm po< mo Hwnmcm H m

 

 

.ooom pm dame HH¢

.wovfixopmd HmOHHpoEEmmcz use aonHpoEEzm no nude QOmHHwQEoo .m oHnme

37

activation values differing by five to seven entropy units,
as shown by the data in Table 3.

These observations and results indicate that it
would be informative to make a study of decomposition
rates of additional compounds in the series of peroxides
described above as well as in additional mixed series of
heterocyclic peroxides, such as symmetrical and unsymmetri-

cal compounds containing oxygen and nitrogen hetero-atoms.

SUMMARY

(1) Eight previously unreported unsymmetrical
peroxides containing one benzene and one hetero-aromatic
ring were prepared and the kinetics of the decomposition
of six of these peroxides were investigated.

(2) For the compounds investigated the kinetics
was found to be first order in presence of a free radical
scavenger.

(3) Energies of activation, frequency factors
and entropies of activation were calculated and conclu-
sions were drawn from the values obtained as to the influ-
ence of substituents on the rate constants and the kinetic

parameters.

38

(l)
(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

LITERATURE CITED

Brown, D. J., J. Am. Chem. Soc., pg, 2657 (1940).

Erlenmeyer, E. and Schoenauer, W., Helv. Chim. Acta.,

Bartlett, P. D. and Nozaki, K., J. Am. Chem. Soc.,
gg, 1686 (1946).

Swain, C. G., Stockmeyer, W. T. and Clarke, J. T.,
J. Am. Chem. Soc., 12, 5426 (1950).

Bloomquist, A. T. and Buselli, A. J., ibid, 13, 3883
(1951)-

Hammett, L. P., Physical Organic Chemistry, McGraw-
Hill Book Co., New York, 1940.

 

Breitenbach, J. W. and Karlinger, H., Monatsh., 80,
739 (1949)-

Schuetz, R. D. and Teller, D. M., J. Org. Chem., g7,
410 (1962).

Schuetz, R. D., Gruen, F. M., Byrne, D. R. and
Brennen, R. L., J. Heterocyclic Chem., 3, 184
(1966).

Gruen, F. M., Ph.D. Thesis, Michigan State University,
1964, p. 50.

Hine, J., Physical Organic Chemistry, McGraw Hill
Book Co., New York, 1962, p. 444.

 

Leffler, J. E., J. Am. Chem. Soc., 12, 67 (1950).

Glasstone, S., Laidler, K., and Eyring, H., The
Theory of Rate Processes, McGraw Hill Book Co.,
New York, 1941, DP. 1461150.

 

Hartough, H. D. and Kosak, A. I., J. Am. Chem. Soc.,
19, 3498 (1948).

Hartough, H. D., ThiOQhene and Its Derivatives,
Interscience Publishers, Inc., New York, 1952,

p- 505-

 

39

(l6)

(17)

(18)

(19)
(20)

(21)

(22)

(23)
(24)

(25)
(26)

(27)

(28)

(29)

(30)

(31)

(32)

40

and Imoto, E., Bull.
Ser. A, 6, 127 (1958).

Nishimura, J., Motoyama, R.
Univ. Osaka Perfect:

Campaigne, E., and LeSuer, W. M., J. Am. Chem. Soc.,
19, 1555 (1948).

King, J. W., and Nord, F. F., Org.
(1948).

Chem., M3, 635

Steinkopf, W. 273 (1935)-

515,

and Jacob, H., Ann.,

Hartough, H. D., ThiOphene and Its Derivatives,
Interscience Publishers, Inc., New York, 1952,
p- 378.

Hartough, H. D. and Conleg L. G., J. Am. Chem. Soc.,
92. 3069 (1947).

Campaigne, E. and Archer W. C., J. Am. Chem. Soc.,
12. 989 (1953).

N.Ph. Buu Hoi, J. Chem. Soc., 1721 (1958).

Migridichian, V., Organic Syntheses, Vol.
hold Publishing Corp., New York, 1957, p.

II, Rein-
258.

19. 419 (1943).

Schuetz, R. D., and Teller, D. M., J. Org. Chem.,
g1, 410 (1962).

Dann, 0., Ber.

Ford, M. C., and MacKay, D., J. Chem. Soc., 4620

(1957).

Braun, G., Organicg§yntheses, Col. Vol. I, John
Wiley and Sons, Inc., New York, 1956, p. 431.

 

Gould, E. S., Mechanism and Structure in Organic
Chemistry, Holt, Rinehart and Winston, New
York, 1959, p. 676.

 

Ferguson, L. N., The Modern Structural Theory of
Organic Chemistry, Prentice Hall, Inc., Engle-
wood Cliffs, New Jersey, 1964, p. 277.

 

Bartlett, P. D., et a1., J. Am. Chem. Soc., 89, 1398
(1958)-

Bunnett, J. F., in A. Weissberger, Technique of
Organic Chemistry, Vol. VIII—Part I, Inter—
science Publishers, Inc., New York, 1961,

p- 199.

 

41

(33) Ng. Ph. Buu Hoi and Hoan, N., Rec. Trav. Chim., 68,
5 (1949).

(34) M. Sy, Ng. Ph. Buu Hoi and Xuong, Ng. D., J. Chem.
500-, 1975 (1954)-

(35) Frankland and Aston, J. Chem. Soc., 79, 511 (1901).

APPENDIX

43

 

 

 

 

 

 

 

Table 4. Spectroscopic measurements leading to kinetic data.
2-thenoyl benzoyl peroxide
Temp.: 72.90°C.10.05°C. Solvent: CClu plus 0.2M. styrene
3322:: :12: I I A A
Run No. l
1 0 117.8 3.0 39:27 .59406 0.20249
2 180 118.6 7.5 15.81 .19893 0.07846
360 118.4 15.5 7.638 .88298 -0.05409
540 118.4 23.0 5.147 .71155 -0.l4283
5 720 118.9 30.0 3.963 .59802 -0.22330
6 900 117.8 39.0 3.021 .48015 -0.31876
Slope: -5.72 x 10‘” k = 1.32 10‘3 min.‘1
Run No. 2
l 0 118.3 6.6 17.92 .25334 0.09795
2 180 118.9 8. 13.67 .13577 0.05538
360 116.0 16.1 7.261 .86100 -0.06500
540 118.3 22.9 5.116 .71315 -0.14685
5 720 117.8 30.8 3.825 .58263 -0.23463
6 900 117.8 39.0 3.0205 .48015 -0.31858
Slope: —4.63 x 10‘” k = 1.07 x 10‘3 min.-1

44

 

 

 

 

 

 

 

Table 5. Spectroscopic measurements leading to kinetic data.
2—thenoyl benzoyl peroxide

Temp.: 82.17°C.10.02°C. Solvent: CClu plus 0.2M. styrene

33:35:: 31:? I. I so A A

Run No. 1
1 0 118.8 1.4 84.86 1.92870 0.28533
2 60 117.8 8.0 14.73 1.16820 0.06744
3 120 117.8 16.2 7.272 0.86165 -0.06464
4 180 118.4 25.5 4.643 0.66680 —0.l7600
5 240 118.5 33.4 3.548 0.54998 —0.25964
6 300 117.6 41.5 2.834 0.45240 -0.34448

Slope: -1.70 x 10'3 K = 3.91 x 10'3 mln.‘1

Run No. 2
1 0 118.7 2.7 43.96 1.64306 0.21564
2 60 119.2 9. 12.04 1.08063 0.02383
3 120 118.9 15.2 7.822 0.89332 -0.04900
4 180 119.0 24.9 4.779 0.67934 -0.l6794
5 240 118.3 34.1 3.469 0.54020 —0.23745
6 300 118.5 42.4 2.795 0.44638 -0.35028

Slope: -1.78 x 10‘3 k = 4.09 x 10‘3 min.’1

45

 

 

 

 

 

 

 

Table 6. Spectroscopic measurements leading to kinetic data.
2-thenoyl benzoyl peroxide
Temp.: 90.35°C.t0.05°C. Solvent: CClu plus 0.2M. styrene
2:22;: 1:2“: I A A A
Run No. 1
l 0 120. 3.6 33.44 1.52427 0.18298
2 15 120. 9.0 13.33 1.12483 0.05115
30 120. 12.7 9.480 0.97681 -0.01019
45 120. 18.6 6.457 0.81003 -0.09151
5 60 120. 21.9 5.511 0.74123 -0.13006
6 75 120. 30.2 3.980 0.59988 —0.22192
Slope: -5.05 x 10"3 k = 1.16 x 10‘2 '1
Run No. 2
1 0 120. 3.5 34.43 1.43694 0.18667
2 15 120. 7.7 15.64 1.19424 0.07700
3 30 120. 11.8 10.20 1.00860 0.00389
4 45 118. 18.4 6.462 0.81037 —0.09130
5 60 119. -2.4 5.348 0.72819 —0.l3775
6 75 120. 29.8 4.050 0.60746 -0.2l345
SlCube: —5.22 x 10'3 k = 1.20 x 10‘2 '1

46

 

 

 

 

 

 

 

Table 7. Spectroscopic measurements leading to kinetic data.
3-thenoyl benzoyl peroxide
Temp.: 72.90°C.10.05°C. Solvent: CC14 plus 0.2M. styrene
33:25:: 3.1:? I I Io/I I A
Run No. 1
l 0 119.2 6.7 17.79 1.25018 0.09691
2 180 119.0 10.8 11.02 1.04218 0.00787
3 360 119.1 16.0 7.444 0.87181 —0.05958
4 540 119.4 24.4 4.893 0.68958 —0.l6140
5 720 118.9 32.0 3.716 0.57008 -0.24405
6 900 118.9 38.2 3.113 0.49318 -0.30698
Slope: -4.57 x 10'” k = 1.05 x 10’3 min.-1
Run No. 2
1 0 118.7 5.1 23.28 1.36698 0.13577
2 180 118.3 10.4 11.38 1.05614 0.02366
360 118.2 16.4 7.207 0.85775 -0.06661
540 118.0 23.2 5.086 0.70638 -0.15095
5 720 118.1 32.5 3.634 0.56038 -0.25150
6 900 117.5 38.9 3.021 0.48015 -0.31858
Slope: -5.05 x 10'“ k = 1.16 x 10"3 mln.’1

47

 

 

 

 

 

 

 

Table 8. Spectroscopic measurements leading to kinetic data.
3-thenoyl benzoyl peroxide

Temp.: 82.17°C.t0.02°C. Solvent: CClu plus 0.2M. styrene

33:32:: 5:21? I. I I./I A A

Run No. l
1 0 117.8 4.3 27.40 1.43775 0.15776
2 60 118.2 8.8 13.43 1.23808 0.05231
3 120 118.5 16.9 7.012 0.84584 -0.07273
4 180 118.4 23.6 5.017 0.70044 -0.15465
5 240 117.9 30.8 3.828 0.58297 -0.23433
6 300 118.6 40.0 2.965 0.47202 -0.34606

Slope: —1.60 x 10'3 k = 3.69 x 10'3 min.-

Run No. 2
l 0 117.6 4.5 26.13 1.41714 0.15137
2 60 118.0 10.0 11.80 1.07188 0.03019
3 120 117.5 16.7 7.036 0.84733 -0.07l96

180 119.0 24.0 4.958 0.69531 -0.15783

5 240 118.7 31.4 3.780 0.57749 -0.23845
6 300 118.3 39.2 3.018 0.47972 -0.31903

Slope: -l.55 x 10'3 = 3.62 x 10'3 min."1

48

 

 

 

 

 

 

 

Table 9. SpectrOSCOpic measurements leading to kinetic data.
3-thenoyl benzoyl peroxide

Temp.: 90.35°C.i0.05°C. Solvent: CClu plus 0.2M. styrene

3335i? 51?." I I Io/I A 10% A

Run No. 1
l 0 119.9 4.0 29.98 .47683 0.16938
2 15 120.5 8.2 14.70 .16732 0.06707
3 30 119.9 12.4 9.669 .98538 '-0.00643
4 45 120.4 18.0 6.688 .82530 -0.08339
5 60 119.7 22.8 5.250 .72016 -0.21063
6 75 119.7 29.0 4.128 .61574 —0.21063

Slope: -4.96 x 10-3 k = 1.14 x 10-2 -1

Run No. 2
l 0 119.5 4.8 24.90. .39620 0.14489
2 15 119.4 9.4 12.70 .10380 0.04297
3 30 120.3 13.1 9.183 .96298 -0.01637
4 45 120.5 17.1 7.047 .84800 -0.07l60
5 60 119.6 22.8 5.246 .71983 -0.14229
6 75 119.9 27.3 4.392 .64266 -0.l9199

Slope: —4.37 x 10‘3 k = 1.01 x 10"2 ‘1

49

 

 

 

 

 

 

 

Table 10. Spectroscopic measurements leading to kinetic data.
(5—methy1-2-thenoyl) benzoyl peroxide
Temp.: 72.90°C.*0.05°C. Solvent: CClu plus 0.2M. styrene
33:25:: as: I. I I A
Run No. l
1 0 123.2 3.7 33.30 1.52244 0.18241
2 180 123.2 12.3 10.02 1.00087 0.00043
360 123.7 24.6 5.029 0.70148 —0.15397
540 123.6 34.2 3.614 0.55799 -0,25337
5 720 123.0 46.7 2.634 0.42062 -0.37613
6 900 123.5 58.5 2.111 0.32449 -0.48829
Slope: -7.27 x 10‘” k = 1.68 x 10'3 min.”1
Run No. 2
1 0 123.5 5.0 24.70 1.39270 0.14395
2 180 123.9 14.3 8.664 0.93772 -0.02794
3 360 123.4 25.0 4.936 0.69338 -0.15902
4 540 123.8 35.2 3.517 0.54617 —0.26265
5 720 123.1 46.3 2.659 0.42472 -0.37l92
6 900 123.5 57.8 2.137 0.32980 -0.48175
Slope: -6.77 x 10'” k = 1.56 x 10‘3 min.‘1

Table 11.

Temp.:

50

(5-methyl-2-thenoy1) benzoyl peroxide

82.17°C.10.02°C.

Solvent:

Spectrosc0pic measurements leading to kinetic data.

001“ plus 0.2M. styrene

 

 

 

 

 

 

 

33:25:: 11:? I I./I A A

Run No. 1
1 0 122.4 5.0 24.48 1.38881 0.14270
2 60 122.7 13.3 9.226 0.96501 —0.01547
3 120 121.1 23.3 5.197 0.71575 -0.14521
4 180 120.8 37.0 3.265 0.51388 -0.28912
5 240 121.0 47.6 2.542 0.40518 -0.39233
6 300 121.4 61.0 1.990 0.29885 -0.52447

Slope: —2.20 x 10‘3 k = 5.06 x 10"3 min.-

Run No. 2
1 0 121.7 5.2 23.40 1.36922 0.13640
2 60 121.3 14.5 8.365 0.92247 -0.03503
3 120 121.5 24.8 4.899 0.69011 -0.l6109
4 180 121.2 36.2 3.348 0.52479 -0.28001
5 240 121.9 48.7 2.503 0.39846 -0.39957
6 300 121.3 60.8 1.995 0.29994 -0.52302

Slope: .2.15 x 10‘3 k = 4.95 x 10'3 mln.’1

51

 

 

 

 

 

 

 

Table 12. Spectroscopic measurements leading to kinetic data.
(5-methy1-2—thenoyl) benzoyl peroxide

Temp.: 90.35°C.10.05°C. Solvent: 001“ plus 0.2M. sytrene

3:31:32: 11:? I. I I./I I I

Run No. 1
l O 120. 6.3 19.11 .28126 0.10755
2 15 120. 9.5 12.70 .10380 0.09297
3 30 120. 17.“ 6.920 .84011 -0.07567

40 120. 25.8 4.659 .66829 -O.17503

5 60 120. 45.0 3.942 .53681 -0.27019
6 75 120. 41.9 2.869 .45773 —0.33942

Slope: -6.29 x 10_3 k = 1.44 x 10"2 min.-1

Run No. 2
1 O 120. 4.2 28.69 .45773 0.16376
2 15 120. 10.1 11.88 .07782 0.03141
3 30 120. 18.6 6.452 .80969 -0.09168
4 45 120. 25.8 4.679 .66969 —O.17412
5 60 120. 35.1 3.925 .53466 -0.27189
6 75 120. “3.0 2.802 .HM7U7 -0.34921

Slope: -6.78 x 10"3 k = 1.56 x 10"2 '1

Table 13.

52

(5-ethy1-2-thenoy1) benzoyl peroxide

Spectroscopic measurements leading to kinetic data.

 

 

 

 

 

 

 

Temp.: 72.90°C.*0.05°C. Solvent: 001“ plus 0.2M. styrene
3:25;: 112:: I I I
Run No. 1
1 0 119.4 4.9 24.37 .38686 0.14208
2 120 119.5 10.4 11.49 .06032 0.02531
3 240 119.9 16.6 7.223 .85872 —0.06616
360 120.1 25.8 4.655 .66792 —0.17529
5 480 120.0 36.4 3.279 .51812 -0.28559
6 600 119.9 43.4 2.763 .44138 -0.35517
Slope: -8.40 x 10‘” k = 1.94 x 10‘3 min._1
Run No. 2
1 0 120.2 5.2 23.12 .36399 0.13481
2 120 120.0 12.1 9.917 .99638 -0.00157
240 120.7 18.6 6.489 .81218 -0.09034
4 360 118.9 24.1 4.934 .69320 -0.15914
5 480 120.2 35.7 3.367 .52724 -0.27802
6 600 119.8 42.5 2.819 .45010 -0.34669
Slope: -7.87 x 10-“ k = 1.81 x 10-3 min.-1

Table 14.

Temp.:

53

(5-ethyl-2-thenoyl) benzoyl peroxide

82.17°10.02°C.

Solvent:

Spectroscopic measurements leading to kinetic data.

001“ plus 0.2M. styrene

 

 

Sample

Time

 

 

 

 

 

Number Min. I Io/I A log A

Run No. l
1 0 118.9 4.8 24.77 1.39393 0.14426
2 60 119.0 15.5 7.677 0.88519 -0.05296
3 120 118.8 27.2 4.368 0.64028 —0.19362
4 180 118.7 36.8 3.226 0.50866 -0.29354
5 240 118.5 50.9 2.328 0.36698 -0.56193
6 300 119.0 63.3 1.880 0.27416 -0.56193

Slope: —2.28 x 10‘3 k = 5.24 x 10‘3 min.-

Run No. 2
1 0 118.9 6.0 19.82 1.29710 0.11294
2 60 118.1 15.7 7.522 0.87633 —0.05735

120 118.5 26.2 4.523 0.65543 -0.18349

4 180 118.1 40.5 2.916 0.46479 -0.33273
5 240 118.3 52.2 2.266 0.35526 —0.44940
6 300 118.0 62.6 1.885 0.27531 -0.56019

SIOpe: -2.23 x 10’3 k = 5.14 x 10‘3 min.‘1

Table 15.

54

(5-ethyl-2-thenoyl) benzoyl peroxide

Temp.:

90.35°C.10.05°C.

Solvent:

Spectroscopic measurements leading to kinetic data.

CClu plus 0.2%. styrene

 

 

 

 

 

 

 

3312:: 1:31? I Io/I I I

Run No. 1
1 0 120.7 3.7 32.62 1.51348 0.18013
2 15 120.3 12.5 9.624 0.98336 -0.00727
3 30 119.7 18.9 6.333 0.80161 -0.09604
4 45 120.5 26.9 4.480 0.65128 -0.18622
5 60 120.5 34.6 3.483 0.54195 -0.26600
6 75 120.3 46.2 2.604 0.41564 -0.38132

Slope: -7.00 x 10‘3 k = 1.61 x 10'2 '1

Run No. 2
1 0 121.2 4.2 28.86 1.46030 0.16435
2 15 121.3 10.3 11.78 1 07115 0.02979
3 30 121.4 19.0 6.390 0.80550 -0.09393
4 45 121.6 26.7 4.554 0.65839 -0.18151
5 60 120.5 35.1 3.433 0.53567 -0.27108
6 75 121.0 44.2 2.738 0.43743 -0.35912

Slope: -6.87 x 10‘3 k = 1.58 x 10‘2 ‘1

Table 16.

55

(5-t-butyl-2-thenoyl) benzoyl peroxide

Temp.:

72.90°C.10.05°C.

Solvent:

Spectroscopic measurements leading to kinetic data.

001” plus 0.2M. styrene

 

 

Sample Time

 

 

 

 

 

Number Min. I 10/1 A 10% A
Run No. 1
l 0 120.3 4.7 25.60 .40824 0.14860
2 180 120.5 13.9 8.669 ~97797 -0.02780
360 120.9 23.2 5.221 .71775 -0.14400
540 119.7 33.4 3.584 .55437 -0.25618
5 720 120.1 42.0 2.860 .45637 -0.34065
6 900 120.2 53.1 2.364 .35488 -0.44989
Slope: -6.42 x 10'” k = 1.48 x 10"3 min.-1
Run No. 2
1 0 121.3 6.0 20.22 .30578 0.11594
2 180 120.6 12.9 9.349 .97077 -0.01287
3 360 121.0 23.4 5.171 .71357 -0.14655
540 120.8 33.7 3.585 .55449 -0.25610
5 720 120.1 43.0 2.793 .44607 -0.35057
6 900 120.5 52.8 2.282 .35832 -0.44575
Slope: —6.24 x 10-“ k = 1.44 x 10"3 min."1

Table 17.

56

(5-t-butyl-2-thenoyl) benzoyl peroxide

Temp.:

82.17°C.10.02°C.

Solvent:

Spectroscopic measurements leading to kinetic data.

CClu plus 0.2M. styrene

 

 

Sample

Time

 

 

 

 

 

Number Min. I Io/I A log A
Run No. l
1 0 120.3 5.3 22.70 .35603 0.12226
2 60 120.4 14.0 8.600 .93450 -0.02942
120 120.7 25.7 4.697 .67182 -0.17276
183 120.1 37.6 3.194 .50433 —0.29731
5 240 120.4 46.9 2.567 .40943 —0.38285
6 300 120.4 57.8 2.083 .31869 -0.49662
Slope: -2.04 x 10’3 k = 4.69 x 10‘3 min.-
Run No. 2
1 0 119.8 5.3 22.60 .35411 0.13162
2 60 120.3 15.5 7.761 .88992 -0.05066
3 120 120.8 26.2 4.611 .66380 -0.17796
4 183 119.8 36.3 3.300 .51851 -0.28525
5 240 120.2 47.4 2.536 .40415 —0.39340
6 300 120.2 58.0 2.072 .31639 -0.49976
Slope: -2.04 x 10'3 k = 4.70 x 10‘3 mln.‘1

Table 18.

57

(5-t-butyl-2-thenoyl).benzoyl peroxide

Temp.:

90.35°C.10.05°C.

Solvent:

Spectros00pic measurements leading to kinetic data.

001“ plus 0.2m. styrene

 

 

 

 

 

 

 

33:28:: 71:: I I./I I I

Run No. l
1 0 120.1 6.2 19.37 1.28713 0.10958
2 15 120.2 10.8 11.13 1.04650 0.01995
3 30 120.0 18.8 6.383 0.80502 -0.09420
4 45 120.1 25.5 4.710 0.67302 —0.17198
5 60 120.2 33.6 3.577 0.55108 —0.25877
6 75 120.2 40.9 2.939 0.46820 —0.32957

Slope: -5.92 x 10'3 k = 1.36 x 10’2 '1

Run No. 2
1 0 120.0 7.1 16.90 1.22789 0.08920
2 15 120.4 11.9 10.12 1.00518 0.00217
3 30 119.9 18.2 6.588 0.81875 -0.08682
4 45 120.6 26.9 4.483 0.65157 -0.18602
5 60 120.4 32.8 3.671 0.56478 —0.24811
6 75 120.5 40.1 3.005 0.47784 —0.32075

Slope: —5.52 x 10‘3 k = 1.27 x 10'2 ‘1

Jun

.. C.

2;

Table 19.

Temp.:

58

(5-nitro-2-thenoyl) benzoyl peroxide

72.90°C.10.05°C.

Solvent:

Spectrosc0pic measurements leading to kinetic data.

001“ plus 0.2M. styrene

 

 

Sample

Time

 

 

 

 

 

Number Min. I Io/I A log A
Run No. l
1 0 120.0 13.4 8.955 .95207 -0.02.32
2 120 119 0 23.4 5.086 .70638 -0.15095
240 119.9 35.7 3.359 .52621 -0.27885
4 360 119.9 46.9 2.557 .40773 -0.38966
5 480 120.2 53.5 2.247 .35160 -0.45395
6 600 120.2 60.1 2.000 .30103 —0.52l43
Slope: -8.38 x 10‘" k = 1.93 x 10‘3 mln."1
Run No. 2
1 0 121.3 11.5 10.55 .02325 0.00988
2 120 120.8 24.3 4.971 .69644 -0.15714
240 119.8 36.6 3.273 .51495 —0.28819
360 119.5 42.5 2.812 .44902 -0.34775
5 480 119.9 54.0 2.220 .34635 -0.46042
6 600 117.5 59.7 1.968 .29403 -0.53165
Slope: —9.76 x 10‘” k = 2.02 x 10"3 min.'1

Cur.-

Table 20.

59

(5-nitro-2-thenoyl) benzoyl peroxide

Temp.: 82.17°C.10.02°C.

Solvent:

Spectroscopic measurements leading to kinetic data.

CClu plus 0.2g. styrene

 

 

Sample Time

 

 

 

 

 

Number Min. I Io/I A log A
Run No. l
l 0 121.9 12.5 9.752 .98909 -0.00476
2 60 122.0 32.0 3.813 .58127 -O.23560
3 120 122.0 46.3 2.635 .42078 -0.37592
180 119.0 56.2 2.117 .32572 -O.487l8
5 240 119.9 64.2 1.868 .27138 -0.56639
6 300 119.1 72.9 1.364 .21325 -0.67101
Slope: -2.11 x 10"3 k = 4.86 x 10‘3 min.“1
Run No. 2
1 0 119.0 12.8 9.297 .96834 -0.0l399
2 60 118.5 30.4 3.898 .59084 -0.22856
120 118.7 44.3 2.680 .42813 -0.36845
180 119.0 57.3 2.077 .31744 -O.49839
5 240 118.6 65.4 1.814 .25864 -O.58737
6 300 118.8 73.7 1.612 .20737 -0.68319
Slope: -2.17 x 10-3 k = 4.99 x 10_3 min.-

60

 

 

 

 

 

 

 

Table 21. SpectrOSCOpic measurements leading to kinetic data.
(5-nitro-2-thenoyl) benzoyl peroxide

Temp.: 90.35°C.10.05°C. Solvent: CClu plus 0.2%. styrene

33:25:: 11:? I Io/I I I

Run No. l
1 0 120.6 11.1 10.87 .03623 0.01536
2 11 121.1 20.9 5.794 .76298 -0.11748

20 121.5 27.0 4.500 .65321 -0.18495

4 30 121.1 33.4 3.626 .55943 -0.25228
5 40 120.9 40.7 2.971 .47290 -0.38891
6 50 120.9 47.2 2.561 .40841 -0.38891

Slope: -7.83 x 10‘3 k = 1.80 x 10’2 ’1

Run No. 2
l 0 121.0 10.8 11.20 .04922 0.02078
2 11 122.6 18.0 6.811 .83321 -0.07925
3 20 120.4 26.3 4.578 .66068 -0.l8000
4 30 121.7 35.1 3.467 .53995 -0.26761
5 40 121.5 41.4 2.935 .46761 -0.33013
6 50 120.8 47.0 2.570 .40993 -0.38732

Slope: -8.30 x 10‘3 k = 1.91 x 10'2 '1

61

.AMHV COHPGSUm WCHCHNnm 039 EOLVH UGCHGPQO **

.B\H omefiowe x moa no oofio o soon ooofioeoo *

 

 

 

 

. moucom
. . m.sm mm.ma em om a I
mo.oa mHOH x :m.: .mH mm.om Hsoom
®O.m mHOH K NH.H . m NmH MW.: NH.N® AH%OC®£BIN
oa.m mH.m mHOH x Hm.H m Hm mm o:.H om.me -Hmeom167mv
mo.m maoa x mm.a . : sm.ma mm.om Hzowcom
mm.w :HOH N mm.m . 2 mm mHom NH.N@ AH%OC®£BIN
mw.m m>.w Hoa x ma. m om mew sm.H om.m~ namnpmnmv
mw.o mHOH x oa.o . mm.om Hzopcom
. OH x >~.m m.w: mm :H . Aazoconelm
.OH mm.ww maoa x :H.m w.am mma Honm wm.mm lazspoznmv
m mm.oe MMOH x mm.m mm: mm H mm.om
NS.HH mHWM w wmuw m.mm o.mma mw.ma efi.mm Mmmmmmm m
. m.HH . . u
m HH m:.HH mwoa x em.o mmo HH H MM.MM
mm.mH ease e some a.mm o.mwe mm.wn ee.mw Heoeeom
N.NH mm NH mflww H mw.m mam SH.H ee.me Heoeoee-m
r NH mH
1, 1.1
)V3 )V3 9 WWW MW xw um
MMHM. WHHMM S wwndw de 0 %Mw
mm® “Law m . WM mm (Wow. MW 950980
18.45 445 .. we: «4% m ken
one No I wmm % _ ea
(\ I
«eu.J "wTe a. o
w * I .
.woofixOLoQ mo opmo oHpocfix .mm canoe

flue. w u... w... rfituu.» ~mu.~L. 4* .1. fish» rhea}.

Per Cent Transmission

100

75

50

25

62

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4 1
i- -1
*4 M
1. 4 4 _
I l l 1 I I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 1. Quantitative infrared spectra of the

decomposition of 2-thenoy1 benzoyl
peroxide at 72.90° in carbon tetra-
cloride, 0.2g. in styrene.

Per Cent Transmission

100

75

U1
0

25

63

 

 

 

 

 

 

Z
Z
7’
K
K

:\

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J I I I I I

5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Figure 2. Quantitative infrared spectra of the

decomposition of 2-thenoy1 benzoyl
peroxide at 82.17° in carbon tetra-
chloride, 0.2fl. in styrene.

Per Cent Transmission

100

75

U1
0

25

64

 

 

 

 

 

K
/

“MW

1’
Z

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

l I J l I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 3. Quantitative infrared spectra of the

decomposition of 2-thenoyl benzoyl
peroxide at 90.35° in carbon tetra-
chloride, 0.2M. in styrene.

Per Cent Transmission

65

100

 

 

 

 

 

 

 

 

 

 

 

 

5o~- 4U -

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0 I I l l I I
5.7 5-7 5-7 5-7 5.7 5-7

Wavelength in Microns

 

Figure 4. Quantitative infrared spectra of the
decomposition of 3-thenoyl benzoyl
peroxide at 72.90° in carbon tetra-
chloride, 0.2M. in styrene.

Per Cent Transmission

66

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1
If 7 n .
I ..
I
4 I 7

 

 

 

5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Figure 5. Quantitative infrared spectra of the
decomposition of 3-thenoyl benzoyl
peroxide at 82.17° in carbon tetra-
chloride, 0.2fl. in styrene.

Per Cent Transmission

100

75

50

25

67

 

f

 

i:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

!

 

 

5.7

Figure 6.

5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of 3—thenoyl benzoyl
peroxide at 90.35° in carbon tetra-
chloride, O.2M. in styrene.

Per Cent Transmission

100
75 - ”Jr/I k
50 L. h 4 v
25 —-
0 I I I I I I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 7. Quantitative infrared spectra of the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

decomposition of (5—methyl-2-thenoyl)
benzoyl peroxide at 72.90° in carbon
tetrachloride, 0.2g. in styrene.

 

 

Per Cent Transmission

69

 

100

75 I-

50 h

 

25 —

 

 

 

J
:3
j

7‘“

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I J I I l

 

 

5.7

Figure 8.

5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of (S-methyl-Z-thenoyl)
benzoyl peroxide at 82.17° in carbon
tetrachloride, 0.2g. in styrene.

Per Cent Transmission

100

50

25

71

 

 

 

 

 

 

f

mew

[‘M
fi/h I 1

I 7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J I l I l I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 10. Quantitative infrared spectra of the

decomposition of (5-ethyl-2-thenoyl)
benzoyl peroxide at 72.90° in carbon
tetrachloride, 0.2g, in Styrene.

Per Cent Transmission

100

50

25

70

 

I”

 

 

 

 

 

J
3
5

Wm‘

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F- M fl 8 ‘8¢r/J jg]!
1] l _J l I 11. l
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 9. Quantitative infrared spectra of the

decomposition of (5-methyl-2-thenoyl)
benzoyl peroxide at 90.35° in carbon
tetrachloride, 0.2g. in styrene.

Per Cent Transmission

100

75

U1
O

25

72

 

 

 

I

‘17

 

 

 

 

 

 

WWWN

7

I I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L —

A I I I I I

5-7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Figure 11. Quantitative infrared spectra of the

decomposition of (5-ethy1-2-thenoyl)
benzoyl peroxide at 82.17° in carbon
tetrachloride, 0.2g. in styrene.

Per Cent Transmission

100.

W
O

25

73

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I I I I I

 

 

5.7

Figure 12.

5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of (5-ethyl—2-thenoyl)
benzoyl peroxide at 82.17° in carbon
tetrachloride, 0.2M. in styrene.

Per Cent Transmission

74

 

100

507—

 

 

 

 

f
3

R

1 1
75 --

PM

6
5

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

25—
0 I .J 11 I 11 I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 13. Quantitative infrared spectra of the

decomposition of (5-t-butyl-2-thenoyl)
benzoyl peroxide at 72.90° in carbon
tetrachloride, 0.2g, in styrene.

 

Per Cent Transmission

75

 

100

__.;=v

75--

UT
0
T

 

25'-

 

 

 

 

 

\

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L I | I l

 

5.7

Figure 14.

5.7 5.7 5.7 5.7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of (5—t-butyl—2-thenoyl)
benzoyl peroxide at 82.17° in carbon
tetrachloride, 0.2g. in styrene.

Per Cent Transmission

76

 

100
W

1
75—{

50 I-I

 

 

 

 

 

 

 

 

 

25'—

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 15.

5.7 5-7 5.7 5-7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of (5-t-butyl-2-thenoyl)
benzoyl peroxide at 90.35° in carbon
tetrachloride, 0.2g. in styrene.

 

Per Cent Transmission

77

 

100
7.1
1

50-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

25— —
0 1 1L J I .L
5-7 5.7 5.7 5.7 5-7 5.7
Wavelength in Microns
Figure 16. Quantitative infrared spectra of the

decomposition of (5-nitro-2-thenoyl)
benzoyl peroxide at 72.90° in carbon
tetrachloride, 0.2M. in styrene.

Per Cent Transmission

100

75

50

25

78

 

 

 

 

 

 

 

 

 

l l

 

 

 

 

 

 

 

 

 

 

 

v

 

 

5.7 5.7

Figure 17.

5.7 5.7 5.7 5.7
Wavelength in Microns

Quantitative infrared spectra of the
decomposition of (5-nitro-2-thenoyl)
benzoyl peroxide at 82.17° in carbon
tetrachloride, 0.2M, in styrene.

Per Cent Transmission

100

75

50

25

79

 

WI»

 

 

 

 

 

 

 

 

 

If/‘W/H WIM-

 

 

 

 

 

 

 

 

 

 

 

- -
I I I I I I
5.7 5.7 5.7 5.7 5.7 5.7
Wavelength in Microns
Figure 18. Quantitative infrared spectra of the

decomposition of (5-nitro-2-thenoyl)
benzoyl peroxide at 90.35° in carbon
tetrachloride, 0.2g. in styrene.

80

2

0.

8s

v-

.oofipoanomhpop conmmo cfi mpfixomoa Hmoncon
AamocoanwIHmnuoEImv mo Eduuooam oopmpmcH

950.91 78 xȤ..~>(3

«. 2 o. o O A

8o 80 000. 8: SN— §— 81— 8&—
.‘U g‘azg‘;

. .. 1.2002... 103...). I Ill-07.! Ion-:3 on... 0! :2... pivot. uni-8.0.. III

.ma ohsmfim

 

81

V.

.oofinoanomppou cognac :H oofixomom ahoucon
AazoconplmlaznpoImv mo Esmpooam UoAMMMCH

”229.1 2. InOZdfi><3

B a. : o. o a n

00¢ 009 08. 8: 8a. 80. 8: 80.
.10 881329155
I c; «69.193533145295386!i155!!!)

.om oeswem

 

$25“

(3":

82

Q.

n.

'—

.oofimoanommpop connmo CH oofixopoa Hmoucon
AamocoanmIHmpsnIplmv mo Esmpoomm ponmmmcH

algg ,8 EUZudH>(3

n- n. 2 o. o O h

FE H— _.
com 009 000— 8: 8m. 82 81 con—

. 3U "5332*?"

a 1.. 1.8.023. x0325. .32 587320.: («luv-o 0;! 0.. =1!» :59: col-3.0... I:

.Hm opowfim

 

.oofimoanomppop conpmo CH opaxopom Hmoucon
AazocmszmIoppficlmv mo Esmpooam oohmmmsH .mm omswfim

nZO~U_I Z. I»02w3>(>a

I a. S 2 o. u o m o n u l. m

 

Ono 8x 000 80 08. 00: 8a— 86— 001 8a. coon can Gen 8.: 08¢

75 man! .Zw)<>r

. £1 3 {‘23 icon-3.2 . r. Julia—ol- g g... .9 in g i 3'. 4‘ 3 1.2:

84

om.m mm.m mw.m ww.m mw.m mw.m :m.m mw.m mw.m Hw.m om.m m>.m

#

MOH x B\H

_ A A d

I mm<

HIoHoe .Hpo oom.am I
moa x mm.o| "oaoam

.oofixonoa Hmoucon AahocoanmIHmpzn
Ipnmv mo coaum>fipow mo hwpocm

4

.mm onsmflm

m>.m w>.m ow.m m>.m

J 5

8

om

.m

ow.m

o~.m

I om.m

oo.m

om.m

oz.m

x 301 -

I oa.m

 

TE

"111111111111111111111111111111111“