The electrolytic oxidation of benzene and its related compounds.

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Content THE ELECTROLYTIC OXIDATION OF BENZENE
AND ITS RELATED COMPOUNDS
A T h e s is
P re se n te d ' t©
The F a c u lty o f th e D epartm ent o f C hem istry
U n i v e r s i t y o f S o u th e rn C a l i f o r n i a
In P a r t i a l F u l f i l l m e n t
o f th e R eq u irem en ts f o r t h e Degree
M a ste r o f S c ie n c e i n C h em istry
by
A rc h ie P i e p e r
June 1940
UMI Number: EP41518
All rights reserved
INFORMATION TO ALL USERS
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In the unlikely event that the author did not send a complete manuscript
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a note will indicate the deletion.
UMI'
D issertate PjHuhhfl
UMI EP41518
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This thesis, written by
........................ a r c h j e .p i e p e r ..............................
under the direction of h.X& Faculty Committee,
and a p p ro ved by all its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial fulfill
ment of the requirements for the degree of
MASTER OF SCIENCE
Dean
Secretary
JUNE -1-940- Date.
Faculty Com m ittee
Chairman
CONTENTS
Page
I n t r o d u c t i o n --------------------------------------------------------------- 1
E l e c t r o l y t i c O x id a tio n o f Benzene------------------------ 3
P a s t I n v e s t i g a t i o n s ----------------------------------------- — — 12
D e s c r i p t i o n o f th e C e l l - - --------------------------- 17
A n a l y t i c a l P ro c e d u re — 19
R e s u l t s o f th e I n v e s t i g a t i o n -------------------- 23
C o n c lu s io n ------------------------------------ 37
R e f e r e n c e s ------------------------------------------------------------------ 4 l
I n t r o d u c t i o n
B ecause o f th e r e c e n t l y r e v i v e d i n t e r e s t i n e l e c t r o - o r g a n i c
c h e m is tr y a n d th e f a c t t h a t e l e c t r o - c h e m i s t r y i n g e n e r a l may s h o r t l y
see much grow th i n S o u th e rn C a l i f o r n i a , t h i s work was u n d e r ta k e n .
What s t a r t e d o u t t o he a g e n e r a l e l e c t r o - o r g a n i c pro b lem n arrow ed
down to one c o n c e rn in g th e p r o d u c t i o n o f quinone and hydro q u in o n e .
T h is i s n o t w ith o u t im p o rta n c e i n S o u th e rn C a l i f o r n i a , w here one o f
th e n a t i o n s l a r g e i n d u s t r i e s , th e m o tio n p i c t u r e i n d u s t r y , i s one
o f th e g r e a t e s t u s e r s o f h y d ro q u in o n e an d r e l a t e d compounds.
A re v ie w o f th e c h e m ic a l l i t e r a t u r e h a s shown t h a t e l e c t r o -
o r g a n ic m ethods compare f a v o r a b l y w ith p u r e l y c h e m ic a l m ethods f o r
c e r t a i n s y n th e s e s b e lo n g in g to t h e f o l lo w in g g e n e r a l c l a s s e s o f
r e a c t i o n s : c o u p lin g , o x i d a t i o n , r e a c t i o n s w i t h h a lo g e n s , and r e
d u c t i o n s . E l e c t r o - o r g a n i c m ethods have b een u se d m ost s u c c e s s f u l l y
i n s y n t h e s i s by r e d u c t i o n .
S ince i t s i n c i p i e n c y i n th e e a r l y p a r t o f t h e n i n e t e e n t h
c e n t u r y e l e c t r o - o r g a n i c c h e m is tr y h a s b e e n th e s u b j e c t o f a l a r g e
number o f r e s e a r c h e s . I t i s i n t e r e s t i n g to n o t e , how ever, t h a t
t h e s e r e s e a r c h e s have b een p u t t o c o m p a r a tiv e ly l i t t l e p r a c t i c a l
u s e . The number o f p a t e n t s i n t h i s f i e l d i s s m a ll and e l e c t r o
c h e m ic a l p r e p a r a t i o n s a r e r a r i t i e s in th e o r g a n ic c h e m ic a l l a b
o r a t o r y m an u a ls.
S h e rlo c k Swann, J r i n h i s summary o f h i s s e a r c h o f th e l i t
e r a t u r e f o r e l e c t r o - o r g a n i c p r e p a r a t i o n s l i s t s o n ly th o s e w hich g iv e
y i e l d s e q u a l o r s u p e r i o r to th o s e o b ta in e d p u r e l y by c h em ic al
m eth o d s. The a b se n c e o f quin one i s n o te w o rth y . T h is , how ever,
does n o t mean t h a t th e com m ercial p r o d u c tio n o f e l e c t r o l y t i c
q u in o n e is n o t f e a s i b l e , n o r does i t mean n e c e s s a r i l y , t h a t i t
c o u ld n o t be made t o g iv e b e t t e r y i e l d s t h a n by p u r e l y c h em ic al
m e th o d s.
2
Quinone i s made i n l a r g e am ounts by o x i d iz i n g a n i l i n e ; t h i s
b e in g th e most common c h e m ic a l method u s e d . Sodium o r p o ta s s iu m
d ie h ro m a te may be em ployed a s th e o x i d i z i n g a g e n t s when a low tem
p e r a t u r e i s u s e d , and th e o x i d i z i n g a g e n t i s added s l o w l y A l t h o u g h
th e h ig h s t a b i l i t y of t h e quinone s t r u c t u r e to w a rd o x i d a t i o n makes
p o s s i b l e th e u se o f so 'p o w erfu l a n o x i d i z i n g a g e n t a s d ie h ro m a te i n
a c i d s o l u t i o n , some c a re m ust s t i l l be e x e r c i s e d i n o r d e r t o p r e v e n t
d e s t r u c t i v e r e a c t i o n . P h e n o l a s w e l l a s p a r a d i s u b s t i t u t e d compounds
may be u s e d i n th e d i l u t e d ie h ro m a te and s u l p h u r i c a c i d s o l u t i o n to
g iv e q u in o n e .
Quinone may be re d u c e d to h y d ro q u in o n e by a lm o s t any o f th e
common r e d u c in g a g e n t s . S u lp h u r d io x id e b u b b le d i n t o a quinone
s o l u t i o n i s p e rh a p s th e m ost common.
E l e c t r o l y t i c O x id a tio n o f Benzene
I t i s now p o s s i b l e t o r e p r e s e n t th e co urse o f o x i d a t i o n o f
benzene a s f o llo w s
H
o
/
H
o
or
3
Dis/ntejrat/on Products
o
ti
4
ti
o
C .O O H
Q-lt
* L S -
C'tt
N CW/f
I t I s f a i r l y c e r t a i n t h a t p h e n o l I s t h e f i r s t p r o d u c t o f t h e
e l e c t r o l y t i c o x i d a t i o n o f b e n z e n e , b u t a s I t i s im m e d ia te ly o x id iz e d
to c a t e c h o l (2) and h y d ro q u in o n e (3) i t i s n o t e a s i l y d e t e c t e d . By
e l e c t r o l y z i n g a s o l u t i o n of benzene i n a c e t i c a c i d , u s i n g an o d es
o f l i , P t , Gu or E e, p h e n o l was d e f i n i t e l y i s o l a t e d , a lth o u g h th e
y i e l d d id n o t e x c e e d 2%. I f a n a q ueous s u s p e n s io n was u se d no
p h e n o l c o u ld be i d e n t i f i e d .
C a te c h o l r e a d i l y u n d e rg o e s d i s i n t e g r a t i o n a t an an ode, and
so th e amount p r e s e n t i n th e e l e c t r o l y t e i s a lw ay s s m a ll; n e v e r
t h e l e s s , i t h a s been d e t e c t e d q u a l i t a t i v e l y a s a r e s u l t of th e
o x i d a t i o n o f a s u s p e n s io n o f benzene i n d i l u t e s u l p h u r i c a c i d a t
P t , Pb o r g r a p h i t e a n o d e s .
H ydroquinone and quinone (4) a r e o b ta in e d b y th e e l e c t r o l y t i c
o x i d a t i o n o f b e n z e n e ; th e c o n d i t i o n s a r e g e n e r a l l y such t h a t th e
fo rm er i s o x id iz e d t o t h e l a t t e r , b u t i f th e e l e c t r o l y t e i s
4
a llo w e d a c c e s s t o t h e c a th o d e t h e quinone i s re d u c e d h a c k to
h y d r o q u in o n e .
When p h e n o l i s o x i d iz e d e l e c t r o l y t i c a l l y , h y d ro q u in o n e and
quinone a r e formed a s i s t o he' e x p e c te d from th e shove scheme,
h u t i n a d d i t i o n t o d i s i n t e g r a t i o n p r o d u c t s , opM.iph.enol (6) and
p p r-d .ip h e n o l (7), w hich a r e p r o b a b ly i n t e r m e d i a t e s i n th e form a
t i o n o f c a t e c h o l and h y d r o q u in o n e , a r e a l s o o b t a i n e d .
Dim tegra * , o p ojutfs
The e l e c t r o l y t i c o x i d a t i o n o f h y d ro q u in o n e u n d o u b te d ly
y ie ld s , q u in o n e , h u t th e m o le c u la r compound q u in h y d ro n e (one mol
q u in one and one mol h y d r o q u in o n e ) may he p r e c i p i t a t e d owing to
i t s r e l a t i v e l y sm a ll s o l u b i l i t y .
I t h a s b een c laim ed t h a t i n th e p r e s e n c e o f a manganese
s a l t a s c a t a l y s t quinon e i s o b t a i n e d . The s p a r i n g l y s o l u b l e
qu in h y d ro n e i s e v i d e n t l y more r e a d i l y o x id iz e d by an o x i d i z i n g
a g e n t , i . e . , Mn i n a h ig h v a le n c y s t a t e , i n s o l u t i o n , th a n i t i s
a t t h e anode i n th e a b sen c e o f a Mn compound. F u r t h e r o x i d a t i o n
o f quinone l e a d s t o m a le ic a e i d (5) a s i n d i c a t e d a n o t h e r b r e a k
down p r o d u c t s .
5
P h e n o lic e t h e r s , e . g . a n i s o l e , a r e o x id iz e d a n o d i e a l l y t o
q u in o n e •
I n g e n e r a l , benzene d e r i v a t i v e s behave i n a s i m i l a r manner
to b e n ze n e when a n o d i e a l l y o x i d iz e d . An e m u lsio n o f io d o b e n z e n e ,
f o r exam ple, g iv e s h y d ro q u in o n e an d i t s o x i d a t i o n p r o d u c t s , t o
g e t h e r w i t h iodic a c i d , when o x id is e d i n a d i v id e d c e l l : i f no
d iaphragm i s u s e d h y d ro q u in o n e an d io d in e a r e form ed by a re d u c
t i o n o f th e a n o d ic p r o d u c t s . I n a d i l u t e s u l p h u r i c a c i d e m u lsio n
e h lo ro b e n z e n e i s o x i d iz e d t o benzo q u in o n e a t a l e a d a n o d e .
W ith to lu e n e and i t s d e r i v a t i v e s t h e p o s s i b i l i t i e s o f
o x i d a t i o n a r e g r e a t e r , b u t th e same f e a t u r e s c h a r a c t e r i z e th e
a n o d ic p r o c e s s e s a s a r e fo u n d w i t h b e n z e n e . B oth quinone and
m e th y l quinone may be o b ta in e d from t o l u e n e .
The d e f i n i t e o x i d a t i o n o f the r i n g i n c y c l i c compounds i s
a d i f f i c u l t t a s k f o r t h e r e a s o n t h a t t h e o x i d a t i o n e i t h e r does
n o t to u c h th e n u c l e a r c a rb o n atom s o r e l s e i t b r e a k s t h e r i n g .( ^
U nder c e r t a i n c o n d i t i o n s e i t h e r th e r i n g o r th e s id e c h a in may
be o x id iz e d e l e c t r o l y t i c a l l y w i t h v e ry e x c e l l e n t r e s u l t s . I n
th e o x i d a t i o n of th e r i n g , t h e f i r s t s te p i s u s u a l l y t h e i n t r o
d u c ti o n o f a h y d ro x y l group fo llo w e d by t h e o x i d a t i o n o f t h i s
to q u in o n e , a s p r e v i o u s l y m e n tio n e d . There seems t o be a d i f
f e r e n c e o f o p in io n a s to j u s t how th e m echanism of t h i s o x id a
t i o n t a k e s p l a c e .
One i n v e s t i g a t o r c o n c lu d e s t h a t th e f o r m a t io n o f t h e above
h y d r o x y lic d e r i v a t i v e s may be due t o th e a c t i o n o f n a s c e n t p e r -
s u l p h u r i c a c i d e l e c t r o l y t i c a l l y form ed a t th e anode from t h e
6
s u l p h u r i c a c i d w hich i s n e a r l y alw ay s used i n some amount i n th e
e l e c t r o l y t e . He mahes t h i s a s su m p tio n b e c a u se many o rg a n ic
compounds, e s p e c i a l l y th e a r o m a tic s e r i e s , a r e changed i n t h i s
manner by the a c t i o n o f p e r s u l p h a t e . A n o th e r t h e o r y i s t h a t th e
n a s c e n t oxygen p ro d u ce d a t t h e e l e c t r o d e i n t e r f a c e a c t s d i r e c t l y
a s th e o x i d i s i n g a g e n t . I n some c a s e s t h e r e may be' added to th e
e l e c t r o l y t e c e r t a i n s a l t s w hich sp eed up th e a b s o r p t i o n o f oxygen
so t h a t th e r a t e o f o x i d a t i o n a s w e l l a s t h e e l e c t r i c a l e f f i
c ie n c y of th e p r o c e s s i s i n c r e a s e d . Such s a l t s a r e t h o s e o f
m anganese, chromium and c e riu m . I n th e c ase when chrom ic a c id
was p r e s e n t , th e o rg a n ic d e p o l a r i z e r would be o x i d iz e d and th e
chrom ate io n re d u c e d t o c h ro m ic , w hich i n t u r n w ould be o x id iz e d
b a c h t o chrom ate a t t h e a n o d e . The e l e c t r o l y t i c re g e n e ra tio n o f
th e chrom ic a c i d sh o u ld heep pace w i t h i t s r e d u c t i o n to chrom ic
io n f o r m ost s a t i s f a c t o r y r e s u l t s .
.. As a r u l e , o r g a n ic compounds a r e too p o o r c o n d u c to r s of
e l e c t r i c i t y to be u se d w ith o u t a n added e l e c t r o l y t e . ® Since
i t i s v e ry d i f f i c u l t to r e g u l a t e th e e l e c t r o d e p o t e n t i a l f o r
any one r e a c t i o n i t i s n o t o f t e n t h a t a l l th e oxygen i s a b o so rb e d
by th e d e p o l a r i z e r ; t h a t w hich i s n o t a b so rb e d by t h e d e p o la r
i z e r depends on s e v e r a l c o n d i t i o n s , w hich i n c l u d e f i r s t , th e
n a t u r e o f t h e d e p o l a r i z e r , becau se some compounds a r e more e a s i l y
o x i d iz e d t h a n o t h e r s . The c u r r e n t d e n s i t y a l s o a f f e c t s th e
th e r e a c t i o n b e c a u se i t i n f l u e n c e s th e r a t e o f e v o l u t i o n of
oxygen a t th e e l e c t r o d e , one f a r a d a y l i b e r a t i n g one e q u i v a l e n t
o f oxygen. O th e r f a c t o r s w h ich must be c o n s id e r e d a r e d i f f u
s i o n o f th e d e p o l a r i z e r and i t s c o n c e n t r a t i o n , th e s i z e o f th e
anode s u r f a c e , t h e e f f e c t o f s t i r r i n g th e e l e c t r o l y t e , th e
7
c a t a l y t i c i n f l u e n c e o f added compounds, t e m p e r a t u r e , th e n a t u r e
o f th e anode m a t e r i a l , and t h e s o l v e n t . The same changes may
he a f f e c t e d i n th e o p e r a t in g system t y a l t e r i n g one o f two o r •
t h r e e o f t h e s e f a c t o r s . F o r exam ple, th e G.D. may he i n c r e a s e d
hy e i t h e r d e c r e a s i n g th e anode s u r f a c e a r e a o r i n c r e a s i n g th e
a m p e ra g e .
C e l l v o l t a g e a p p e a r s a s a f u n c t i o n o f th e t e m p e r a t u r e ,
c u r r e n t s t r e n g t h , th e c o n d u c t i v i t y o f th e e l e c t r o l y t e , an d th e
p o l a r i z a t i o n o f th e e l e c t r o d e .
The p ro b lem s f a c e d i n th e e l e c t r o l y t i c o x i d a t i o n o f benzene
a s w e l l a s th e effe cts o f d i f f e r e n t i n f l u e n c i n g f a c t o r s have
been e x c e l l e n t l y sum m arized by F r . F i c h t e r i n one o f h i s l e c
t u r e s . ®
"S in c e th e s t a r t o f o rg a n ic e l e c t r o c h e m i s t r y by M ic h ae l
F a rad a y an d by C h r i s t i a n F . S c h o en b ein , th e a tt e m p t h a s o f t e n
b een made t o u t i l i z e e l e c t r i c c u r r e n t s a s o x i d i z i n g a g e n t s i n
th e p r e p a r a t i o n o f com m ercial o r g a n ic compounds, b u t. th e f i r s t
triu m p h a n t s u c c e s s e s w ere f o llo w e d by a s e r i e s o f d i s a p p o i n t i n g
f a i l u r e s , owing to the. m oderate y i e l d s a n d th e d i f f i c u l t y o f
r e g u l a t i n g th e a c t i o n o f e l e c t r o l y t i c oxygen. Most o r g a n ic
compounds w ere c o m p le te ly o x i d iz e d , y i e l d i n g c a rb o n d io x id e
an d w a te r a s th e f i n a l p r o d u c t s . I f we c o u ld f i n d th e r e a s o n
why t h i s o x i d i z i n g p r o c e s s does n o t w ork sm o o th ly , and c o u ld
c o n t r o l i t to go o n ly a s f a r a s we w is h e d , we s h o u ld be i n a
p o s i t i o n to employ i t more s u c c e s s f u l l y .
8
An a r o m a tic h y d ro c a rb o n su c h a s benzene h a s th e d is a d v a n ta g e
o f b e in g i n s o l u b l e i n an aq u eo u s e l e c t r o l y t e • S in c e benzene
i t s e l f i s a n o n - c o n d u c t o r , i t can n o t be u s e d w ith o u t a m in e r a l
a c i d or a s a l t i n aq u eo us s o l u t i o n , and v i g o r o u s s t i r r i n g m ust
be employed t o p ro d u ce a n e x c e e d in g ly f i n e e m u ls io n w hich w i l l
Mien behave l i k e a t r u e s o l u t i o n .
The e l e c t r o c h e m i c a l o x i d a t i o n o f benzene was f i r s t s t u d i e d
i n 1880 by R e n ard , who f a i l e d t o r e c o g n iz e th e n a t u r e o f th e
p r o d u c t o b t a i n e d . JGattermann and F r i e d r i c h fo u n d , 14 y e a r s
l a t e r , t h a t th e o x i d a t i o n l e a d s to th e f o r m a t io n o f q u i n o l .
The f i n a l p ro d u c t d e p en ds somewhat on th e c o n s t r u c t i o n
o f th e a p p a r a t u s . I f a p la t i n u m anode and a d iap h rag m a re
u s e d , n o t q u i n o l, b u t b e n z o q u in o n e , i s o b t a i n e d , w h i l e , w ith o u t
a c la y diarjhragm , q u i n o l i s p ro d u c e d , b e c a u se t h e quinon e i s
r e a d i l y re d u c e d a t th e c a th o d e . The t r a n s f o r m a t i o n o f quinone
i n t o q u in o l h a s a c e r t a i n p r o t e c t i v e a f f e c t . Kempf p ro v e d t h a t
quinone a lo n e i s a t t a c k e d a t a p la tin u m anode an d d i s i n t e g r a t e s
w i t h t h e f o r m a t io n o f d i b a s i c a l i p h a t i c a c i d s , such a s m a le ic
a c i d . Q u in o l, on t h e c o n t r a r y , i s o x id iz e d to q uinon e a lo n e ,
w ith o u t d e s t r u c t i o n o f th e n u c l e u s . I f , from t h i s v ie w p o in t,
th e c o o p e r a t i o n o f th e c ath o d e seems a n a d v a n ta g e , i t s h o u ld
n o t be f o r g o t t e n t h a t i t a l s o means a l o s s o f c u r r e n t ; i n s t e a d
o f a c t i n g on benzene th e a n o d ic oxygen i s p a r t l y c o n s e rv e d i n
t h e u s e l e s s r e o x i d a t i o n o f q u i n o l .
\
9
The f i r s t p r o d u c t i n th e o x i d a t i o n o f benzene m ust he
p h e n o l, w hich t h e n u n d e rg o e s f u r t h e r o x i d a t i o n in two d i r e c t i o n s :
t o q u in o l and q u in o n e , a n d t o p y r o c a t e c h o l . l’ h e l a s t named,
w hich i s r e a d i l y o x id iz e d f u r t h e r , a p p e a r s o nly t o a s m a ll
e x t e n t .
A lth o u g h we have n o t h e en a b l e so f a r to i s o l a t e p h e n o l
from th e e le c tr o 3 „ y tic c e l l , n e v e r t h e l e s s we p o s t u l a t e i t a s
th e f i r s t p r o d u c t . Benzene i t s e l f r e s i s t s e l e c t r o c h e m i c a l
o x i d a t i o n f a i r l y w e l l . I t i s a l s o v e ry r e s i s t a n t t o p u r e l y
c h e m ic a l o x i d i z i n g a g e n t s , s i n c e i t i s a t t a c k e d o n ly by ozone,
h y d ro g en p e r o x i d e , and m o n o p e rs u lp h u ric a c i d , and t h e y a l s o
f u r n i s h p y r o c a t e c h o l and q u i n o l . I f i t i s d e s i r e d to o x id iz e
b e n z e n e , a h ig h o x i d a t i o n p o t e n t i a l a t th e anode I s n e c e s s a r y ;
th e f i r s t s te p i s m ost d i f f i c u l t . But a s soon a s b en zen e i s
t r a n s f o r m e d i n t o p h e n o l th e o x i d a t i o n c o n ti n u e s f r e e l y , f o r th e
p h e n o l i s s o l u b l e i n th e aqueo us e l e c t r o l y t e and t h e m o le cu le
o f p h e n o l i s much e a s i e r t o a t t a c k . There a r e now two v u l
n e r a b l e p o s i t i o n s , n a m e ly , th o s e o r t h o and p a ra to th e f i r s t
h y d ro x y l g ro u p .
The r e s u l t s f u r n i s h e d i n th e c ase o f benzene p r o v e :
Cl) t h a t e l e c t r o c h e m i c a l o x i d a t i o n i s a m ost e f f e c t i v e means
o f o x i d a t i o n , and i s , i n f a c t , a lm o s t to o s t r o n g f o r o r g a n ic
compounds; (2) t h a t th e e a r l i e s t s t a g e o f t h e o x i d a t i o n i s
f r e q u e n t l y , i f n o t r e g u l a r l y , more d i f f i c u l t t o a c h ie v e t h a n th e
su b s e q u e n t o n e s; (3) t h a t a ro m a tic d e r i v a t i v e s show a d i s t i n c t
10
i n c l i n a t i o n to f u r n i s h p h e n o ls , e s p e c i a l l y t h e p o ly p h e n o ls and
q u in o n e s; (4=) t h a t th e o x i d a t i o n p ro c e e d s on s e v e r a l p a r a l l e l
l i n e s , and t h a t i t ends w i t h t h e com plete d i s i n t e g r a t i o n o f th e
compound i n t o c a rb o n d io x id e and w a t e r .
The m ost d is c o u ra g in g - o f th e f o u r p o i n t s i s th e v ig o r o u s
n a t u r e o f th e a t t a c k , 'what can be done to m i t i g a t e i t ?
The m ost obvious e x p e d i e n t , th e i n c r e a s e o f th e c o n c e n tr a
t i o n o f benzene a s a d e p o l a r i z e r , seems t o be e x c lu d e d by r e a s o n
o f th e i n s o l u b i l i t y o f b enzen e i n w a t e r . One m ight u se a n o r g a n ic
s o l v e n t su ch a s a c e to n e , w h ic h w i l l d i s s o l v e t h e b e n z e n e , making
i t m i s c i b l e w ith th e w a te r and p r o d u c in g a homogeneous e l e c t r o
l y t e . In many e a s e s t h i s d e v ic e works w e l l , b u t i t i n v o lv e s th e
s im u lta n e o u s o x i d a t i o n o f th e a c e to n e i t s e l f t o a c e t i c a c i d and
c a rb o n d i o x i d e , w hich means a l o s s o f c u r r e n t .
By a c a r e f u l c h o ic e o f th e m a t e r i a l o f th e anode t h e r e
a c t i o n s may be d i r e c t e d . O x id a tio n p ro c e e d s most v i o l e n t l y on
smooth p la tin u m a n o d e s ; n e x t t o th o s e a re p e r o x i d i z e d l e a d
a n o d e s , w hich we have f r e q u e n t l y u s e d . P r a c t i c a l l y th e same
p r o d u c ts a r e o b ta in e d w i t h an o d es o f g r a p h i t e , b u t th e l a t t e r
d i s i n t e g r a t e m e c h a n ic a lly , and a l s o a b so rb th e o r g a n ic sub
s t a n c e s .
The i n o r g a n i c e l e c t r o l y t e , w hich i s n e c e s s a r y a s a c o n d u c to r
o f e l e c t r i c i t y , h as a l s o a n e f f e c t on th e e x t e n t o f t h e o x i d a t i o n
a s we11 a s on th e d i r e c t i o n i t t a k e s . The m ost f r e q u e n t u se
h a s h i t h e r t o been made o f d i l u t e s u l p h u r i c a c i d . K. E lb s h a s
11
s u g g e s te d t h a t w ith t h i s e l e c t r o l y t e i t i s a m a t t e r of i n d i r e c t
e l e c t r o c h e m i c a l o x i d a t i o n , inasm uch a s s u l p h u r i c a c i d i s f i r s t
o x id iz e d to p e r s u l p h u r i c a c i d , th e l a t t e r a lo n e a c t i n g on t h e
o r g a n ic s u b s t a n c e .
’ T h is h y p o t h e s i s i s to o l i m i t e d . Even i f th e p r o d u c t i o n o f
u n s t a b l e p e r o x id e s u lp h u r compounds i s a d m i t t e d , i t m ust be
b o rn e i n mind t h a t an e l e c t r o c h e m i c a l o x i d a t i o n o f b enzen e w i t h
p h o s p h o ric a c i d o r p e r c h l o r i c a c i d a s e l e c t r o l y t e g i v e s q u a l i
t a t i v e l y th e same f i n a l p r o d u c ts a s s u l p h u r i c a c i d .
I t may be c o n c lu d e d a s a w o rk in g h y p o t h e s is t h a t t h e o x i
d i z i n g a g e n t i s a lw a y s th e same; i t i s a to m ic oxygen. The
v i o l e n c e w ith w hich t h i s a to m ic oxygen r e a c t s depends n a t u r a l l y
on t h e p o t e n t i a l u n d e r w h ich i t i s e v o lv e d , and t h e l a t t e r can
be r e g u l a t e d by th e c u r r e n t d e n s i t y and by th e n a t u r e o f th e
a n o d e . A low c u r r e n t d e n s i t y i s r e q u i r e d f o r good y i e l d s i n
o rg a n ic e l e c t r o c h e m i s t r y *
T hat th e n a t u r e o f t h e e l e c t r o l y t e i n f l u e n c e s th e r e a c t i o n
can be e a s i l y shown i n th e c ase o f b e n z e n e . An a l k a l i n e s o l u
t i o n can n e v e r f u r n i s h q u in o n e , n o t b e c a u se t h e o x i d i z i n g a g e n t
o r t h e f i r s t s t e p o f o x i d a t i o n i s d i f f e r e n t i n an a c i d s o l u t i o n ,
b u t b e c a u se quinone i s n o t s t a b l e i n th e p re s e n c e o f a l k a l i , s i n c e
i t i s tr a n s fo r m e d i n t o brow n, h y d r o x y q u i n o n e - l i k e , b a d ly c h a r a c
t e r i z e d s u b s t a n c e s .
But even b y e x c lu d in g a l k a l i s and u s i n g a c i d e l e c t r o l y t e s
o n ly , s u c c e s s may n o t be a s s u r e d . The c o n c e n t r a t i o n o f th e a c i d
12
a ro u n d th e anode i n c r e a s e s owing t o th e m i g r a t i o n o f th e a n io n .
T h is may in d u ce t h e f u r t h e r t r a n s f o r m a t i o n o f p rim a ry p r o d u c t s
i n t o new compounds, by d e h y d r a t io n or by c o n d e n s a t io n .
She c o o p e r a t i o n o f th e e l e c t r o l y t e c an be made more i n t i m a t e
b y u s i n g th e s o l u t i o n o f a s a l t o f a m u l t i v a l e n t m e t a l , f o r
i n s t a n c e , chromium, m anganese, cerium o r vanadium s a l t s . T his
means a n i n d i r e c t e l e c t r o c h e m i c a l o x i d a t i o n , inasm uch a s t h e
m e t a l l i c io n o f h i g h e r v a le n c y i s th e r e a l o x i d iz i n g a g e n t , i t s
r e g e n e r a t i o n a t the anode b e in g more r a p i d l y e f f e c t e d th a n th e
o x i d a t i o n of th e a r o m a ti c h y d ro c a rb o n . A lth o u g h t h i s m ethod
h a s b e e n d e v e lo p e d f o r com m ercial p u r p o s e s , i t s s t u d y can n o t
e l u c i d a t e th e b e h a v i o r o f a n o d ic oxygen. In f a c t the m anufac
t u r e r s who use 'such p r o c e s s e s f i n d i t more a d v a n ta g e o u s to
s e p a r a t e th e p u r e l y c h e m ic a l o x i d a t i o n of th e o r g a n ic compound
from the e l e c t r o l y t i c r e g e n e r a t i o n of the in o r g a n i c o x i d iz i n g
a g e n t ."
P a s t I n v e s t i g a t i o n s
G atterm ann and F r i e d r i c h s ^ were two o f th e e a r l i e s t
i n v e s t i g a t o r s of th e e l e c t r o l y t i c o x i d a t i o n of o rg a n ic compounds*
They e l e c t r o l y z e d a m ix tu r e of 20 g . o f b e n z e n e , 65 c c . of a l c o h o l
and 1 5 c c. o f 50$ s u l p h u r i c a c i d f o r two days a t a p o t e n t i a l of
6 v o l t s and o b t a i n e d 2 g . o f h y d r o q u in o n e . S ince t h e s o l v e n t
a l c o h o l i s in i t s e l f a n e x c e l l e n t d e p o l a r i z e r , the low y i e l d o f
h y d ro q u in o n e p r o b a b l y was d ue to t h e o x i d a t i o n of t h e s o l v e n t .
G. Chaveau® s a y s i n h i s re v ie w o f th e p r i n c i p a l m ethods
13
u s e d i n th e m a n u fa c tu re o f q uinone; o f the e l e c t r o l y t i c m ethods f o r
th e o x i d a t i o n o f benzene to q u in o n e, t h a t of ]femph (D.R.J?. 13-7251)
a p p e a r s t o be th e b e s t . 1’he r e a c t i o n i s c a r r i e d o u t i n a s u l p h u r i c
a c id -b e n z e n e e m u lsio n , w i t h a l e a d c a th o d e and l e a d d io x id e a n o d e,
u s in g a c u r r e n t of 3 t o 4 amps p e r s q u a r e d e c im e te r of ano de, and
an em f. o f 3 -4 v o l t s . Of th e b en zen e o x id iz e d , 6 5 -70 $ i s c o n v er
t e d to q u in o n e . The e l e c t r o l y t i c method p r e s e n t s a d v a n ta g e s o v e r
th e chrom ic acid, method s in c e s t a r t i n g m a t e r i a l s ' a r e c h e a p e r, and
s i n c e th e o p e r a t i o n i s more r e a d i l y c o n t r o l l e d .
0 . C lau d iu s® r e p o r t s l i t t l e s u c c e s s w ith th e m ethod o f
Zemph, b u t adds t h a t th e o x i d a t i o n was much a c c e l e r a t e d by add
in g a l i t t l e l e a d d io x id e t o t h e anode m ix t u r e .
B e s t c o n d i t i o n s f o r t h e e l e c t r o l y t i c p r e p a r a t i o n o f q u in o n e ,
s t a t e ' Inoue a n d S h ilc a ta £ 0 ) a r e a s f o l l o w s . The c a t h o l y t e i s
composed o f 10 g . o f benzene i n 100 c c . o f 4 fo sodium s u l p h a t e ,
and th e a n o j y t e , zfo s u l p h u r i c a c i d . E l e c t r o d e s : le a d p l a t e s .
C u r r e n t : 2 -3 amps p e r sq u a re d e c i m e t e r . BMP.: 3 -5 v o l t s .
T em p era tu re : l e s s th a n 20° C. Under c o n s t a n t a g i t a t i o n , th e
p r o d u c t i o n of q u in one was 77 fo of t h e benzene u s e d . I f 1 g . o f
sodium a c e t a t e i s added t o t h e a n o l y t e , and t h e c a t h o l y t e i s
5$ s u l p h u r i c a c i d , th e y i e l d r i s e s to 8 1 .5 $ . The q uinon e p r e
p a r e d u n d e r t h e s e c o n d i t i o n s can be e a s i l y f r e e d from i m p u r i t i e s
by sim p ly w ashing w i t h w a t e r .
An A m erican p a te n t& l) g i v e s t h e f o l lo w in g m ethod o f o x i d i z i n g
b e n z e n e . The b enzene i s in tr o d u c e d i n t o an e l e c t r o l y t e o f
14
g r e a t e r s p e c i f i c g r a v i t y , e . g . , 10$ s u l p h u r i c a c i d s o l u t i o n , so
t h a t i t r i s e s in the e l e c t r o l y t e . When a c u r r e n t i s p a s s e d
th ro u g h t h e e l e c t r o l y t e u s in g l e a d e l e c t r o d e s , t h e n a s c e n t oxygen
pro d u ced o x i d i z e s t h e r i s i n g b e n z e n e . The b e n ze n e i s in tr o d u c e d
in e x c e s s so t h a t th e quinone form ed w i l l b e d i s s o l v e d by i t .
The e l e c t r o l y t i c a c t i o n i s r e p e a t e d u n t i l a s o l u t i o n h ig h i n
qu inone i s o b t a i n e d . Q uinol may be form ed by r e d u c i n g t h e quinone
w i t h s u l p h u r d io x id e .
A german patentP*^ s t a t e s t h a t s a t i s f a c t o r y r e s u l t s a r e
o b t a i n e d when the b e n z e n e i s t r e a t e d w i t h s u l p h u r i c a c i d o f a t
l e a s t 30fa c o n c e n t r a t i o n a n d an e x c e s s o f l e a d d i o x i d e . More
c o n c e n tr a te d a c i d t h a n a t t h e s t a r t may be ad d ed a s th e r e a c t i o n
p r o c e e d s .
A. Seyewetz and G. Miodon&^ o b ta in e d a y i e l d o f 65$ quinone
by em ploying l e a d e l e c t r o d e s s e p a r a t e d by a p o ro u s e a rth e n w a re
diap hragm , and an e l e c t r o l y t e c o n s i s t i n g o f 25$ s u l p h u r i c a c i d
(66 Be) and 33% a c e t i c a c i d , i n w h ic h w as e m u l s i f i e d by c o n t i n
uous s t i r r i n g 2 /3 o f i t s volume o f b e n ze n e. F i n e l y d iv id e d
le a d s u l p h a t e ( 1 - 1 .5 $ ) was em ployed a s a c a t a l y s t , and th e
c o n c e n t r a t i o n of quinone was n o t a llo w e d to e x e e e d 1 fo . The
c e l l was o p e ra te d a t 24° C. w ith a c u r r e n t d e n s i t y of 4 amps
p e r sq u a re d e c im e te r a n d a v o l t a g e of 3 . 2 - 3 ,5 Y. Quinone may
be r e d u c e d q u a n t i t a t i v e l y to h y d r o q u in o l i n a s i m i l a r e l e c t r o
l y t e a t 40 °G ., 1% v a n a d ic a c i d b e in g add ed a s c a t a l y s t . The
benzene s o l u t i o n o f q u in o n e may b® a llo w e d to flo w a s form ed
15
from th e anode t o t h e c ath o d e co m p artm ent, t h e r e “ b e in g re d u c e d
to h y d r o q u in o l.
S c h w a e b e l^ ^ s u g g e s t s t h a t one s o l u t i o n o f th e p ro b le m o f
g e t t i n g good c o n t a c t betw een t h e h y d ro c a rb o n an d th e a c t i v e
e l e c t r o d e may be t o i n j e c t t h e b enzene o r o t h e r h y d ro c a rb o n i n t o
th e aqueous e l e c t r o l y t e i n a f i n e l y d iv id e d s t a t e i n such a
manner, t h a t i t r i s e s o v e r t h e s u r f a c e o f one o f th e e l e c t r o d e s ,
l o r i n s t a n c e , th e compound may be f o r c e d i n th r o u g h a n o z z le
a r r a n g e d b e n e a th an i n c l i n e d anode o f l a r g e s u r f a c e , The benzene
th e n r i s e s a c r o s s t h e ano d e s u r f a c e t o t h e s u r f a c e o f t h e a q ueou s
e l e c t r o l y t e , an d a pump r e c i r c u l a t e s th e su p e rin c u m b e n t l i q u i d th r o u g h
th e n o z z l e . Thus benzene may be o x id iz e d t o b e n z o q u in o n e , o r
t o lu e n e t o t o l u q i n o n e . A nalogous e l e c t r o l y t i c r e d u c t i o n may be
u se d t o c o n v e r t benzoq uino ne t o h y d ro q u in o n e .
B a lfre em an and E h i b b ^ ^ g iv e th e f o llo w in g • s u c c e s s f u l m ethod
f o r th e e l e c t r o l y t i c p r o d u c t i o n o f q u i n o n e . Benzene i s p a s s e d
th ro u g h o r s t i r r e d w i t h a n e l e c t r o l y t e , p r e f e r a b l y c o n s i s t i n g o f
d i l u t e s u l p h u r i c a c i d or a m ix tu re of s u l p h u r i c a c id a n d a
s o l u b l e s u l p h a t e , e . g . , sodium s u l p h a te and i s s u b j e c t e d t o
e l e c t r o l y s i s i n a c e l l i n w hich a n a c t i v e a n d s t a b l e anode o f
l e a d o r l e a d a l l o y and an i n a c t i v e c a th o d e a r e d i s p o s e d , p r e f e r
a b ly c lo s e t o each o t h e r . The c o n c e n t r a t i o n o f q u in o n e i n th e
c e l l i s k e p t low by i t s c o n tin u o u s o r f r e q u e n t re m o v a l. The
benzene s o l u t i o n o f q u ino ne p ro d u ced m a y b e re d u c e d a t a b o u t th e
b o i l i n g p o i n t o f b en ze n e u n d e r such c o n d i t i o n s t h a t th e ben zen e
16
i s d i s t i l l e d o f f and th e h y d ro q u in o n e d i s s o l v e d i n w a t e r .
Thus th e s o l u t i o n may he made t o r u n i n t o a V e s s e l c o n ta in i n g
i r o n b o r i n g s a n d w a t e r m a in ta in e d a t a b o u t 80° G. The benzene
d i s t i l l s o f f and th e h o t s a t u r a t e d l i q u o r s a r e draw n o ff ,
f i l t e r e d h o t and t h e h ydroq u in o n e c r y s t a l l i s e d t h e r e f r o m .
A l t e r n a t e l y , the b e n z e n e -q u in o n e s o l u t i o n may b e ru n i n t o a
s t i l l c o n ta in i n g w a te r i n t o w hich s u lp h u r d i o x id e i s p a s s e d ;
benzene d i s t i l l s o f f a n d th e s o l u t i o n i s w ith d raw n a t i n t e r v a l s .
The a c i d i s t h e n removed b y a l k a l i m etal c a r b o n a te o r h y d r o x id e ,
and th e h y d ro q u in o n e o b t a i n e d by e v a p o r a t i o n .
In c o n t r a s t to t h e v a r i o u s c o n d it i o n s a f f e c t i n g e l e c t r o
l y t i c p r o d u c t i o n o f quinone from benzene a re t h o s e i n w hich
a n i l i n e ^ ^ i s o x id iz e d t o q u i n o n e . The b e s t c o n d i t i o n s a r e
b r i e f l y ( l ) t h e u se o f vanadium p e n to x id e a s c a t a l y s t , (2)
c o n tin u o u s o x i d a t i o n , (3) a h ig h a n o d ic s u r f a c e r e l a t i v e t o
th e q u a n t i t y o f a n o l y t e , (4) c u r r e n t d e n s i t y o f 1 amp. p e r
sq u a re d e c im e te r , and (5) a te m p e ra tu re below 10° G.
I r o n d u s t i n a w a te r s o l u t i o n h a s b e e n u se d s u c c e s s f u l l y
in r e d u c in g t h e quinone form ed t o h y d ro q u in o n e .
17
D e s c r i p t i o n o f th e C e l l
The c e l l ch o sen f o r t h i s work c o n s i s t e d o f a two l i t e r
W eaker, th e i n s i d e o f w h ic h was l i n e d w ith s h e e t l e a d to form
th e a n o d e . The c a th o d e c o n s i s t e d o f s h e e t l e a d made i n t o a
h o llo w c y l i n d e r and p l a c e d i n s i d e a p o ro u s c u p . The p o ro u s cup
\fas p la c e d i n t h e c e n t e r o f th e ‘ b e a k e r a s shoivn i n th e d ia g ra m .
Copper l e a d w i r e s w ere s o l d e r e d t o th e l e a d e l e c t r o d e s .
The b e a k e r r e s t e d i n a w a t e r b a th th r o u g h w hich w a te r was
c i r c u l a t e d f o r te m p e r a tu re c o n t r o l . A g l a s s s t i r r e r , m otor
o p e r a t e d , was p l a c e d i n th e s o l u t i o n betw een th e anode and
p o ro u s c u p . The s i n g l e s t i r r e r gave a s a t i s f a c t o r y s t i r r i n g
or e m u l s i f i c a t i o n and a t th e same tim e k e p t th e m ix tu re i n
c o n s t a n t c i r c u l a t o r y m o tion a ro u n d th e p o ro u s c u p . The m ixin g
o f th e s o l u t i o n s l a s t e d lo n g enough so t h a t a d e c id e d se p a
r a t i o n o f th e p h a s e s d id n o t ta k e p l a c e i n t h a t p o r t i o n o f th e
c e l l o p p o s ite th e s t i r r e r . The c e l l was c o v ered i n p a r t by
a w atch g l a s s to red u c e l o s s e s o f s o l u t i o n by s p l a s h i n g .
A f t e r t h e s w itc h was c lo s e d a ll o w in g p a s s a g e o f th e c u r
r e n t , b o th th e v o l t a g e and amperage were r e a d a t f r e q u e n t i n t e r
v a l s th ro u g h o u t th e c o u rs e o f th e o x i d a t i o n . C u rre n t c o n t r o l
was made w ith a r h e o s t a t o f n o t to o f i n e a d j u s t m e n t . l a t e r
d e te r m i n a ti o n s w ere made w ith th e h e lp o f a s3.ide w ire ?/hich
a llo w e d a d ju s tm e n t f o r v e r y s m a ll c h an g es i n amperage so t h a t
th e c u r r e n t m ig h t be k e p t a s n e a r l y c o n s t a n t a s p o s s i b l e t h r o u g h
o u t th e o x i d a t i o n . An a v e ra g e v o l ta g e f o r eac h d e te r m i n a ti o n
E l e c t r o l y t ic Ce ll
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was o b ta in e d g r a p h i c a l l y *
At th e end o f th e o x i d a t i o n , t h e volume o f th e a n o l y t e was
m easured so t h a t an a l i q u o t p a r t o f t h e quinone s o l u t i o n might-
he t i t r a t e d . -The benzene l a y e r was removed and s t o r e d i n g l a s s
s to p p e r e d b o t t l e s u n t i l th e t i t r a t i o n s c o u ld be made.
I n a l l d e t e r m i n a t i o n s th e c a t h o l y t e c o n s i s t e d o f th e a c i d
used, in th e a n o l y t e . The SO c c . u se d c o n ta in e d no o t h e r s u b s ta n c e
w h a ts o e v e r . 1 ✓
Some c a re must be e x e r c i s e d i n th e o p e r a t i o n o f th e c e l l .
J?or exam ple, th e s o l u t i o n and th e p r o d u c ts o b ta in e d i n th e c o u r s e
o f th e r e a c t i o n must n o t be a llo w e d t o fo rm an im p e rv io u s l a y e r
o f t a r ' o r scum on th e s u r f a c e , n o r c lo g th e p o r e s o f th e d i a
phragm . A c lo g g in g o f th e p o r e s i n c r e a s e s t h e e n e rg y consump
t i o n and c o n s e q u e n tly th e c o s t o f t h e o x i d a t i o n . I f a c c u r a t e
and c o m p a ra tiv e r e s u l t s a r e to be o b ta in e d th e c o n d i t i o n o f t h e
e l e c t r o d e s , e s p e c i a l l y th e a n o d e, m ust be k e p t i n good o r d e r .
'Scum, l e a d s u l p h a t e , and any c o r r o s i v e m a t e r i a l o t h e r t h a n a
smooth c o a t i n g of l e a d d io x id e i s u n d e s i r a b l e . M is le a d in g
r e s u l t s a r e e a s i l y o b ta in e d from a c e l l i n p o o r w o rk in g o r d e r .
A n a l y t i c a l P ro c e d u re
A lth o u g h f o u r v o lu m e tr ic a n a l y s e s ' f o r p u re quinone w ere
u n c o v e re d , t h e q u a n t i t a t i v e a n a l y s i s o f th e p r o d u c t o f f e r e d
some d i f f i c u l t y , Two o f th e m eth o d s, r e d u c t i o n o f quinone to
hy d ro q u in o n e by chromou£p-^ an d t i t a n o u g ^ s o l u t i o n s , were d i s
c a rd e d w ith o u t t r i a l a s b e in g u n s a t i s f a c t o r y . The, fo rm er
\
r e q u i r e d f r e s h l y p r e p a r e d an d s t a n d a r d i z e d s o l u t i o n s w ith t h e
t i t r a t i o n b e in g c a r r i e d out i n an a tm o sp h e re o f c a rb o n d i o x i d e .
The tim e r e q u i r e d a n d th e f a c t t h a t t h e q u in o n e s h o u ld have b e e n
r e l a t i v e l y p u re d is c o u r a g e d i t s u s e .
A t i t r a t i o n o f q u in o n e w i t h a t i t a n o u s s o l u t i o n was a l s o
e l i m i n a t e d s i n c e t h e quinone to he t i t r a t e d h a d t o be p r a c t i c a l l y
p u re and f r e e o f i r o n . T ita n o u s s a l t s a r e e n e r g e t i c r e d u c in g
a g e n t s a n d a r e s t r o n g l y a t t a c h e d b y th e oxygen o f th e a i r , n e c e
s s i t a t i n g a n i n d i f f e r e n t a tm o s p h e r e . B ecause o f t h e s e p r e c a u t i o n s ,
a t i t a n o u s s a l t was fou nd n o t s u i t e d f o r th e o c c a s i o n a l d e te rm in a
t i o n s r e q u i r e d .
I t hap pen s t h a t quinone a c t s d i r e c t l y w i t h t h i o s u l p h a t e
*
th e f i n a l r e a c t i o n b e in g r e p r e s e n t e d b y th e e q u a t i o n :
2C6H 402 + 2S 2 G g - » G 6H2 ( QH)2 (SgO gB .)^* C6H4 (0 H )2
T h is r e a c t i o n can be u s e d f o r t h e d i r e c t t i t r a t i o n of q u in o n e .
The en d p o i n t c an be b a s e d upon th e c o l o r o f th e quinon e s o l u t i o n
i t s e l f o r upon t h e c o l o r o b t a i n e d i n a s p o t t e s t w i t h Y iu rste rf s
s o l u t i o n o f d im e th y l- p - p h e n y le n e d ia m in e • However, i n t h i s c a se
th e t r u e c o l o r o f th e quinone was m ashed, and a n o t to o s a t i s -
I
f a c t o r y s p o t t e s t w as o b t a i n e d . C o n s e q u e n tly i t was d i s c a r d e d
i n f a v o r o f th e v e ry c o n v in c in g i o d i m e t r i c t i t r a t i o n .
' S tr o n g ly a c i d i f i e d quinon e s o l u t i o n i s r e d u c e d q u a n t i t a
t i v e l y t o h y d ro q u in o n e by i o d i d e , and an e q u i v a l e n t amount o f
i o d i n e i s s e t f r e e a n d may b e t i t r a t e d w ith t h i o - s u l p h a t e .
D e s p ite th e f a c t t h e l i t e r a t u r e g i s e l o s e s c e r t a i n w e a h n e sse a
i n t h i s t i t r a t i o n , V s le u r o b ta in e d good r e s u l t s i ^ The r e s u l t s
\
o f such a t i t r a t i o n w ere fo u n d t o b e s a t i s f a c t o r y , and i t was
2 1
a d o p te d - a s t h e a n a l y t i c a l method*
The e x p e r i m e n t a l p r o c e d u re i s to d i s s o l v e th e q u ino ne i n 5 c e .
o f a l c o h o l , t h e n ad d 20 c c . o f 4H HC1 an d 1 .5 g . o f H I, a n d t i t r a t e
th e l i b e r a t e d io d in e im m e d ia te ly w ith t h i o s u l p h a t e *
I n t h e c a se on h a n d , th e q u in o n e sam ple was o b t a i n e d by p i p e t
t i n g d i r e c t l y from th e benzene l a y e r an a l i q u o t p a r t . T h is m eant ;
. th at® a n y o t h e r r e d u c i b l e i m p u r i t y p r e s e n t i n th e ben zen e l a y e r
would be c o n s id e r e d a s q u in o n e . However, a f t e r c o n s i d e r i n g t h e
*
t h e o r e t i c a l p o s s i b i l i t i e s , i t . i s b e l i e v e d t h i s e r r o r i s s l i g h t .
Sam ples o f quinone w ere o b t a i n e d by d i s t i l l i n g o f f t h e benzene
i n a d i s t i l l i n g f l a s h t o t h e p o i n t where th e quinon e s u b lim e d and
c o u ld b e seen a s a y e llo w m is t on th e i n s i d e o f the f l a s h . The
c o n c e n t r a t e d 'r e s i d u e was t h e n c o o le d below room t e m p e r a tu r e a n d
th e c r y s t a l s o f quinone w h ic h form ed f i l t e r e d o f f . These ra n g e d
i n c o l o r from y e llo w t o d eep amber or brow n. P a le y e llo w c r y s t a l s
i
o f quinone w ere t h e n o b ta in e d b y steam d i s t i l l i n g t h e s e c ru d e c ry
s t a l s from a n a c i d s o l u t i o n .
H ydroquinone o r Q uinhydrone may t h e n be p r e p a r e d fro m t h e q u i
none i f d e i s r e d b y r e d u c t i o n w i t h su c h s u b s ta n c e s a s s u l p h u r d i -
os id e , i r o n , f e r r o u s i o n , e t c . ,
I f any quinone were p r e s e n t i n ' t h e a c i d l a y e r , i t w ould n o t
be' i n c lu d e d i n the t o t a l y i e l d o f p r o d u c t s in c e th e a l i q u o t p a r t '
was t a k e n from th e benzene l a y e r . However, on t i t r a t i n g a p o r t i o n
o f th e a c i d 'l a y e r i t was found th a t; t h e quinone d i s s o l v e d t h e r e i n
c o u ld be c o n s i d e r e d n e g l i g i b l e . The amount d i s s o l v e d was f a i r l y
c o n s t a n t a n d h e lp e d com pensate f o r an y o t h e r r e d u c i b l e m a t t e r w hich
V
' I
2 2
m lght be d i s s o l v e d i n the b e n z e n e . I f t h e r e s h o u ld be a c o n s i d e r
a b l e d is c r e p a n c y i n th e y i e l d o f quinone (up t o 10%) i t w ould mean
sim p ly t h a t th e c a l c u l a t e d e f f i c i e n c i e s l i s t e d i n th e t a b l e s w ere
low , a more d e s i r e a b l e c o n d i t i o n t h a n i f th e y w ere too h i g h .
25
R e s u l t s o f th e I n v e s t i g a t i o n
S ince th e p u rp o se o f t h i s i n v e s t i g a t i o n h a s b e en t o d e te r m in e
th e c o n d i t i o n s u n d e r w h ich a maximum y i e l d o f quinone may h e ob
t a i n e d by e l e c t r o l y t i c o x i d a t i o n , i t was n e c e s s a r y t o i n v e s t i g a t e
th e e f f e c t o f each v a r i a b l e an d c o m b in a tio n s o f v a r i a b l e s on th e
y i e l d , The m ost im p o r ta n t v a r i a b l e s b e i n g , a s p r e v i o u s l y d i s c u s s e d ,
h ydrog en io n e o n c e n t r a t i o n , c u r r e n t d e n s i t y , tim e o f r e a c t i o n ,
te m p e r a t u r e , and c a t a l y s t . E ach o f t h e s e an d o t h e r s w i l l b e a n a
l y s e d s e p a r a t e l y and th e maximum c o n d i t i o n s c o r r e l a t e d .
H ydrogen Io n C o n c e n tr a tio n
I n t h e f i r s t t e s t s f o r h y d ro g en io n c o n c e n t r a t i o n , t h e o x i
d a t i o n m ix tu r e c o n s i s t e d o f 250 c c . o f s u lp h u r i c a c i d , 250 c c . o f
ben zen e and 10 grams o f sodium s u l p h a t e . Betw een 10 and 15 c c . o f
th e a c i d were p l a c e d i n s i d e th e p o ro u s cup a s c a t h o l y t e . She
s t r e n g t h s of a c i d u se d w ere 1 0 , 30 and. 50 p e r c e n t by w e ig h t s u l
p h u r ic a c i d . The b e s t c u r r e n t e f f i c i e n c y was o b t a i n e d u s i n g 10
p e r c e n t a c i d a s shown i n f a b l e I ,
The d e t e r m i n a t i o n s w ere r e p e a t e d k e e p in g t h e c u r r e n t th e same
f o r a l l t h r e e a c i d c o n c e n t r a t i o n s ; t h e am perages h a v in g b een d i f
f e r e n t i n th e f i r s t t h r e e r u n s . However, th e r e s u l t s check ed w ith
th o s e of t h e p r e v i o u s r u n , t h e 10 p e r c e n t a c id gave t h e h i g h e s t e
e f f i c i e n c y . See T ab le I a n d g rap h n o . I .
The v e r y p o o r y i e l d w i t h 50 p e r c e n t a c i d was v e ry l i k e l y due
to r u p t u r e o f th e r i n g a f t e r f o r m a tio n o f q u in o n e . The p r e s e n c e
o f c o n s i d e r a b l e scum a n d t h e a b s e n c e o f t h e u s u a l r e d o r am ber
c o l o r i n th e b enzene l a y e r seems t o i n d i c a t e such a p o s s i b i l i t y .
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E f f e c t o f A cid C o n c e n tr a tio n on
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C o n te n ts l y s t ' H2 SO4 H rs. Temp. Y ie ld Y ie ld E f f i c .
250 c c .
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26
C o l o r l e s s m a le io o r m a lic a c i d i s th e n e x t l i n k i n th e benzene
o x i d a t i o n c h a i n . She a b se n c e o f th e ddpp r e d c o lo r i s u n d o u b te d ly
due to e x c e s s iv e o x i d a t i o n . S h is i s th e same r e d c o l o r t h a t i s
o b t a i n e d w ith t h e a c i d wash u s e d on s l i g h t l y im pure benzene
(th io p h e n e p r e s e n t ) . At l e a s t some o f th e r e d c o lo r i s due i n
p a r t t o th e f o r m a t io n o f r e d o -b e n z o q u in o n e . She s t r o n g a c i d
c o n c e n t r a t i o n a p p a r e n t l y g r e a t l y i n c r e a s e s t h e r a t e o f o x i d a t i o n
o f th e q u in o n e .
She 30 p e r c e n t a c i d gave a r e d b e n ze n e l a y e r w h i l e th e 10
p e r c e n t gave a deep orange t o am ber; most o f t h e c o l o r i n th e
l a t t e r was b e l i e v e d t o be due t o q u in o n e .
C u rre n t D e n s ity
She y i e l d o f quinone d e c r e a s e s w i t h d e c r e a s i n g c u r r e n t d e n s i t y
a s i s to be e x p e c te d , b u t th e c u r r e n t e f f i c i e n c y i n c r e a s e s a t
r a t h e r a h ig h r a t e . S h is i s , a s p r e v i o u s l y d i s c u s s e d , b e ca u se
t h e r a t e of e v o l u t i o n of oxygen a t t h e low d e n s i t i e s i s more i n
k e e p in g w ith t h e r a t e a t w hich th e t i n y s l u g s o f benzene come i n
c o n t a c t w i t h th e anode a n d c a n s t i l l b e o x i d i z e d . I t m e re ly
d e c r e a s e s t h e amount o f oxygen l o s t due to to o r a p i d e v o l u t i o n .
Only t h e i n s i d e s u r f a c e o f th e anode h a s b e e n c o n s i d e r e d e f f e c
t i v e , and th e c u r r e n t d e n s i t i e s have b e en c a l c u l a t e d a c c o r d in g ly *
T em perature
The cu rv e o f c u r r e n t e f f i c i e n c y v s . t e m p e r a tu r e shows a
s u r p r i s i n g maximum, th o u g h n o t a l a r g e one, a t a - l i t t l e above
room t e m p e r a t u r e . T h is p r o b a b ly d u e i n p a r t t o more r a p i d evo
l u t i o n o f n a s c e n t oxygen from th e anode and r e c o m b in a tio n to
m o le c u la r oxygen. E v a p o r a ti o n o f benzene above t h i s maximum
m m m
X 28
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T r i a l C e ll Ga t a - ' Amps % Time C. G-ms. T heor.
No. C o n te n ts l y s t . H2 SO4. H rs. Temp. Y ie ld Y ie ld
200 c e .
16, A cid Pb02 5 .0 30 3 .0 234 3 .1 9 1 0.0 8
200 c c . S a t.-
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1 (
17 " " 3 .9 8 30 3<0 22 2 .7 8 8 .0 3
18 ’* 2 .9 5 30 ' 3 .0 21§ 2 .7 1 5 .9 5
19 " ” 2 . 4 30 3 .0 204- 2 .2 5 4 .8 4
10 gm s. -
14 " Na2S0 4, 2 . 7 30 4 .0 ^ 21 2 .9 4 7 . 2 6
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1
24 H * ’ 3 .7 5 10 1 . 5 214- 1 .4 6 3 .7 8
25 4 .0 5 ,1 0 1 . 0 214 0 .9 9 2 .7 2
26 " " 3 .5 10 2 .2 5 v2l4 1 .8 6 5 .2 5
f
C .D .= A m ps X.648 * Approx.
E f f i c .
3 1 .7
3 4 .6
4 5 .5
4 6 .4
4 0 .5
1
3 8 .1
5 1 .1 *
s
38.8
2 6 .3
3 5 .4
V
w m m
I ! I ; I ! I ! : I ! I 1. 11 i I ; I h i
m
5 U
w m m
i
30
T r ia l
No.
8
9
11
V
13
.10
12
E f f e c t o f T em p eratu re on
C e ll C a ta -
C o n te n ts l y s t
200 c c . Na2S04
A cid ' i o gms
200 c c . Pl>02
CgHg 10 gms
II It
200 c c .
Ac i d h
215”c c . -
C6H6
200 c c .
Ac id »
225 c c .
CgH 6
200 c c.
A cid f,
200 c c .
C6H6
200 c c .
A cid h
220 c c.
C6H6
i
Y i e ld o f Quinone
I
T ab le # 3
Amps % Time
H2 SO4 H r s .
4 .7 5 30 4 .0
4 .0 30 4 .0
4 .5 30 4 .0 3
4 .6 5 30 4 .0
4 .7 30 4 .0
3 .9 4 30 4 .7 5
C. Gms. T h eo r.
Temp. Y ie ld Y ie ld
2 4 | 3 .3 6 1 2 .7 6
10 1 .6 7 1 2 .6 2
30^ 4 .1 7 1 2 .1 7
,37 3 .2 9 1 2 .4 9
30 3 .3 3 1 2 .6 2
. . \
29 ,4.35 1 2 .5 7
%
. E f f i c .
2 6 .3 5
1 3 .3 4
34.-3 '
2 6 .3 5
1 "
* ■
2 6 .4
3 4 .6
/
te m p e r a tu r e (30° G .) i s q u i t e r a p i d . v I t was a l s o found t h a t when
i
th e q u in o n e re a c h e d a c e r t a i n c o n c e n t r a t i o n i n t h e b e n z e n e , th e
p r o d u c t i o n o f more q uinone p ro c e e d e d v e r y s lo w ly . T h e r e f o r e , th e
d e c r e a s i n g amount o f benzene a t th e h i g h e r t e m p e r a t u r e s th ro u g h
e v a p o r a t i o n w i l l b r i n g a b o u t ' t h i s l i m i t i n g c o n c e n t r a t i o n f a s t e r
t h a n a t th e lo w e r t e m p e r a t u r e s , t h e r e b y d e c r e a s i n g t h e c u r r e n t
e f f i c i e n c y .
T h is d e c r e a s e c o u ld , o f c o u r s e , b e re m e d ie d b y c o v e r in g t h e
to p o f th e c e l l o r p e rh a p s even em p lo y in g a c o n d e n s e r .
O a l t a l y s t s
S e v e ra l c a t a l y s t s w ere t r i e d a n d gave r e s u l t s v a ry in g up t o
sev en p e r c e n t . Of th o s e t r i e d , a l i t t l e l e a d d io x id e added t o
th e c e l l gave t h e b e s t r e s u l t s . The r e s u l t s o f a d d i n g 10 grams o f
e ach c a t a l y s t to th e c e l l a re shown in t a b l e 4 . The d i f f i c u l t l y
.s o lu b le s a l t s w ere k e p t m e c h a n ic a lly su sp e n d e d i n th e m ix t u r e .
/
P o l a r i z a t i o n was o b s e rv e d i n s e v e r a l o f t h e d e t e r m i n a t i o n s .
P o r exam ple, a t a c o n s t a n t amperage o f t h r e e am peres th e v o l t a g e
a c r o s s th e c e l l b e g a n t o r i s e from an h o u r an d a q u a r t e r to an
h o u r and a h a l f a f t e r th e c e l l had been in o p e r a t i o n . P o l a r i z a
t i o n th e n would a p p e a r t o be a f u n c t i o n o f th e number o f coulombs
/
p a s s i n g th ro u g h t h e c e l l and c o n s e q u e n tly t o th e c o n c e n t r a t i o n o f
th e p ro d u c t in th e c e l l . Graph number 5 shows a t y p i c a l v o l ta g e
v s . tim e c u rv e a t c o n s t a n t a m p erag e. A c o n tin u o u s flow o f r e a c t
a n t s and p r o d u c t i n t h e c e l l w h ich a p p a r e n t l y h a s o c c u re d i n th e
b a tc h d e t e r m i n a t i o n .
mm
33
T r ia l
No.
4
5
\
6
v
7
8
v E f f e c t o f C a t a l y s t s on
N -
Y ie ld o f Quinone
T ab le #4
C e l l C a ta - Amps % Time C. Gms. T h eo r. %
C o n te n ts l y s t H2SO4 H rs. Temp. Y ie ld . Y ie ld . E f f io ,
200 c c.
A cid Pb02 4 .7 30 40 23f 3 .61 1 2 .6 2 2 8 .6
200 c c . s a t .
C6H 6
HS2 SO4 ‘ 4 .8 30 4 .0 23§ 3 . 6 1 , 1 2 .9 0 2 8 .0
S a t.
K2Ci^)7 4 .6 5 30 4 .0 24 2 .6 6 12.4 9 2 1 .3
10 gms
Na2 S0 4 4 .7 30 4 .0 24 3-01 1 2 .6 2 2 3 . ®
10 gms
Na2 S04
10 gm
Pb02
10 gms
Pb02 mS 4 *7 5 3 0 4 , 0 2 4 ^ 3 ,3 6 1 2 *76 2 6 .3 5
✓
' I I I
. (I I
it:
m -tr: tht
■H f + t tf
■m
- + 4
ijfctt
m
M
: f t :
\ 34
'B e n z e n e D e r i v a t i v e s ,
I n o r d e r t h a t a c o s t com parison m ight he made, o t h e r s u b s ta n c e s
b e s i d e b en zene w ere o x i d i z e d . These i n c lu d e d p h e n o l, n itr o b e n z e n e
and s u lp h o n i C a c id .. A n il i n e was c o n s id e r e d b u t e l i m i n a t e d because,
o f i t s p r o p e r ty o f fo rm in g i n s o l u b l e s a l t s i n a c i d s o l u t i o n , t h e
c o n d u c tin g medium chosen f o r t h e s e e x p e r im e n ts .
.P henol gave' one of th e h i g h e s t y i e l d s o f quinone o b ta in e d a s
• )
was t o 'b e e x p e c te d , since., a s m en tio n ed i n th e l i t e r a t u r e , p h e n o l
i s th o u g h t t o be a n i n t e r m e d i a t e s t e p i n t h e f o r m a t i o n o f q u i n o n e ,
by t h e ' e l e c t r o l y t i c o x i d a t i o n o f b e n z e n e . S ince t h e o x i d a t i o n
' i
m ix tu re c o n s i s t e d o f a s o l u t i o n o f p h e n o l i n b e n z e n e , th e t h e o r e
t i c a l y i e l d w i l l depend upon w h e th e r one c o n s i d e r s t h e q u ino ne t o
A
be form ed o n ly from t h e p h e n o l o r from b o t h p h e n o l and benzene,.
T h is can be seen from t h e e q u a t io n s ;
C JBL + 3 ( 0 ) ^ C , H D o + H o0
6 6 6 4 2 2
; 0 6HeO H + S ( d - . O 6H4O2 + H 2O
, >
where t h r e e m oles o f n a s c e n t oxygen a r e r e q u i r e d f o r t h e o x i d a t i o n
o f ben zen e and two f o r p h e n o l . , The c u r r e n t e f f i c i e n c y w as c a l c u
l a t e d b a s in g t h e t h e o r e t i c a l y i e l d on two m oles o f oxygen. T h is
/ ' '
p a r t i c u l a r m ix tu re c o n s i s t e d o f 23 grams o f p h e n o l d i l u t e d t o 200 c c .
w ith b e n z e n e , 200 c c . o f a p p r o x im a te ly 10$ s u l p h u r i c a c i d a n d 2 .5
grams o f l e a d d i o x i d e .
A s t r o n g l y a c i d sod'ium s u lp h o n a te s o l u t i o n was n e x t o x id iz e d
/
a n o d i c a l l y i n th e c e l l . The y i e l d and c u r r e n t e f f i c i e n c y w e r e \v e r y
lo w . Such a low y i e l d was a l i t t l e s u r p r i s i n g i n view o f th e f a c t
%
/
r
36
*
t h a t a s u b s t i t u t i o n a l r e a d y o c c u re d on th e r i n g . T h is su b s ta n c e
was cho sen b e c a u se o f i t s h i g h l y p o l a r n a tu r e so t h a t an in tim a te
c o n t a c t b etw een th e e l e c t r o d e and r e a c t a n t m ight b e o b t a i n e d . The
(2l\
p o o r r e s u l t s w ere p r o b a b ly due t o to o low a n a c id c o n c e n t r a t i o n . ^
S i m i l a r r e s u l t s w ere o b t a i n e d u s in g n i t r o b e n z e n e , a n o n - p o l a r
s u b s ta n c d .
i
\
Quinone from Benzene
36
D e r i v a t i v e s
T able #5
T r i a l C e l l C a ta - Amps % Time C. Gms. T h eo r. %
No. C o n te n ts l y s t H2SO4 H rs . Temp. Y ie ld Y ie ld E fT lc .
200 00 *
26 A cid Pb02 3 -5 10 2 .2 5 2 l £ 1 .8 6 5 .2 5 3 5 .4
200 cc . 2-|- gms
C6h 6
200 c c .
A cid
23 gms
28 C6H5OH Pb02 3 .5 10 2 .0 20 2 .6 8 4 .7 1 38.04-
d i l . t o 2-4- gms
200 cc .
w ith
C6H6
200 c c .
A cid
29 22.2gms Pb02 3*5 10 2 . 0 20 0 .2 3 4 .0 3 5 -71
CgHcSO-^Na 2-|- gms
200 c c .
C6H6
200 cc*.
A cid
27 25 c c . Pb02 3 -5 10 2 .2 5 20i 5 .2 5 -*10
C6H5 NO2 2-|- gms
175 c e .
C6H6
C o n c lu sio n s,
/
(The b e s t c o n d i t i o n s u n d e r which quinon e can be made b y e l e c t r o -
I
l y t i c a l l y o x i d i s i n g benzene i n a n a c i d s o l u t i o n u s in g le a d e l'e e tr o d e s
a r e a s f o l l o w s ;
(1) A s u l p h u r i c a c i d c o n c e n t r a t i o n o f a b o u t 10 p e r c e n t ,h a s
’ /
b e e n fo u n d t o g iv e th e maximum y i e l d o f p r o d u c t ,
(2) The c u r r e n t e f f i c i e n c y v a r i e s i n v e r s e l y w i t h t h e c u r r e n t
d e n s i t y . Of c o u rs e a c u r r e n t o f s u f f i c i e n t m ag nitu de sh o u ld be u se d
such t h a t t h e p r o d u c t is fo rm ed a t a r e a s o n a b le r a t e . T h is seems t o
be a t a c u r r e n t d e n s i t y o f a p p r o x im a te ly 2 amps p e r sq u a re d e c i m e t e r .
(3 ) The optimum te m p e r a tu re a p p e a r s t o be a t a b o u t 3 0° C. T h is
te m p e r a tu r e h a n be m a in ta in e d th ro u g h t h e r e s i s t a n c e o f t h e c e l l ,
b u t even so a v e r y slow c i r c u l a t i o n o f c o o l i n g w a te r w i l l b e r e q u i r e d .
I n a c o m p le te ly e n c lo s e d c e l l w ith c o n d e n s e r , t h e r e i s r e a s o n t o
b e l i e v e t h a t 35° o r p o s s i b l y 40° w ould be t h e b e s t te m p e r a t u r e u n d e r
w h ich t o o p e r a t e . '
i *
( 4 ) Of t h e c a t a l y s t s t r i e d , a l l e x c e p t l e a d d i o x i d e , when c o s t s
/
a r e c o n s id e re d a p p e a r t o be o f l i t t l e v a l u e . The c a t a l y t i c e f f e c t
i s o f s e c o n d a r y im p o rta n c e t o s u c h i n f l u e n c i n g f a c t o r s a s a c i d concen
t r a t i o n and c u r r e n t e f f i c i e n c y , a t l e a s t u n t i l more im p o r ta n t ones
a r e d i s c o v e r e d .
\
( 5 ) A lso o f im p o rta n c e i s t h e e o n c e n t r a t i o n of q u in o n e i n th e
b e n z e n e . The r a t e - o f f o r m a t i o n o f q u in o n e h a s b e e n fo u n d t o d e c r e a s e
w ith i n c r e a s e i n q uinon e e o n c e n t r a t i on. f o r b e s t r e s u l t s i t i s
recommended t h a t th e qiiinone c o n c e n t r a t i o n i s not a llo w e d to e x c e e d '
38
i
*02 grams p e r c c . o f benzene o r a p p r o x im a te ly a 2 . 2 $ s o l u t i o n ,
(
F o r t h i s re a s o n a c e l l w ith c o n tim io n s -flo w i s d e s i r e a b l e . The
same e f f e c t i s n o t i c e d i n a b a t c h p r o d u c t i o n . U sing a c u r r e n t o f '
betw een 3 and 4 amps (C.D. o f 1>8 t o 2*6 am peres p e r s q u a r e d e c i -
' 4
meter-} b e s t r e s u l t s w e re o b t a i n e d b e tw ee n one a n d two h o u r s .
, G e n e r a lly , th e lo n g e r t h e tim e o f o x i d a t i o n the s m a l l e r th e y i e l d ,
_ T aking t h e r e s u l t s o f r u n #21, i n w h ich a c u r r e n t e f f i c i e n c y ■
o f 3 8 .1 p e r c e n t was o b t a i n e d , a s a f a i r a v e r a g e , t h e c o s t o f p r o -
V
d u c in g one pound o f q u in o n e h a s been c a l c u l a t e d ,
'Pow er p e r pound o f quinone $.0535
\
Benzene to - p r o d u c e one l b . o f quino ne ,0372
Removal of Benzene from q u in o n e ( F u e l) ,0017
f .0924
The c o s t o f the power h a s b een b a s e d on h a l f a c e n t p e r k . W. H*
I n c a l c u l a t i n g th e c o s t o f b e n z e n e , 20$ h a s b e e n added t o c o v e r th e
lo s's o f benzene th r o u g h e v a p o r a t i o n and s i d e r e a c t i o n s . T h is sh o u ld
< ' r
be a d e q u a te i f t h e c e l l i s p r o p e r l y c o n s t r u c t e d t o a v o id l a r g e eva
p o r a t i o n l o s s e s . A lth o u g h t h e p -q u in o n e i s f a v o r e d i n the r e a c t i o n ^
x '' 1
t h i s v a lu e m ig h t p o s s i b l y be i n s u f f i c i e n t t o cover t h e s i d e r e a c t i o n
i
l o s s e s . The f u e l c o s t h a s b e e n b a se d on steam a t $ ,5 0 p e r 1000
p o u n d s.
The c o s t o f a c i d an d l e a d d i o x id e have b e en added a s 1 Ofo of th e
above v a l u e . T h is s h o u ld be- more t h a n a d e q u a te s i n c e th e a c i d and
r / %
PbOg c a n be u s e d s u c c e s s f u l l y in a , c o n t i n u o u s p r o c e s s . The c o s t
p e r pound o f q u in o n e , t h e n , s h o u ld r u n a b o u t $ .102 e x c l u s i v e o f
♦
eq u ip m en t, l a b o r , e t c .
The c o s t o f q uinon e p e r pound from p h e n o l i s
Power $*0321
P h e n o l .184
f *216
T h is c o s t i s l i m i t e d by the c o s t o f p h e n o l. These f i g u r e s
$ re f o r a r a t h e r d i l u t e s o l u t i o n o f p h e n o l i n b en zen e w h ic h g i v e s
a low c u r r e n t e f f i c i e n c y * S in e e t h e c o s t o f p h e n o l i s so h i g h by
com p ariso n w ith th e power c o s t , th e h ig h c u r r e n t e f f i c i e n c y t h a t
c o u ld b e o b t a i n e d w i t h a more c o n c e n t r a t e d p h e n o l s o l u t i o n w ould
e f f e c t l i t t l e chang e i n th e t o t a l c o s t . The c o s t l i s t e d above does
n o t i n c l u d e t h e c o s t of f u e l f o r s e p a r a t i n g th e quinon e from t h e
ben ze n e-p h e n o l- s o l u t i o n .
These c o s t s show r a t h e r c o n c l u s i v e l y j u s t how much c h e a p e r
qu ino ne from b en ze n e i s th a n t h a t made from p h e n o l,
,A flo w s h e e t f o r a p i l o t p l a n t f o r m aking q u ino ne or h y d ro -
q u in o n e i s shown i n t h e accom panying d ia g ra m . Such a p l a n t s h o u ld
i
i n c l u d e a c e l l f o r c o n tin u o u s flo w of r e a c t a n t s and a means o f
s a t i s f a c t o r i l y e m u l s i f y i n g th e s e r e a c t a n t s e i t h e r b e f o r e o r a f t e r
t h e y ' e n t e r t h e c e l l . The am ounts o f r e a c t a n t s and power a r e th o s e
r e q u i r e d t o p ro d u ce one pound, o f quinone s u b j e c t to t h e c o n d i t i o n s
s t a t e d i n th e p r e c e d i n g c o s t c a l c u l a t i o n s .
P il o t P l a n t F l o w S h e e t
PbO
> .
Cruel e
Water
fech
— For Quinone
For tiydroQuinone
F igures based on Jpound of Quinone,
41
REFERENCES
(1)
T r a n s a c t i o n s o f t h e E le ctro -C h em . Soc. 69 287(1936)
(2) G -roggins,P.H . U n it P r o c e s s e s In Org. S y n t h e s i s Me G-raw-Hill (1935)
Pg. 339
(3) G -la ssto n e ,S . and A .H ie k lin g E l e c t r o l y t i c O x id a tio n and R e d u c tio n
D. Van N o s tra n d Co. (1936) P g s. 518-320
(4) B ro ck m an ,C .J. E l e c t r o - o r g a n i c C h em istry J.W ile y and Sons (1926)
Pg. 102
(5) See (4) Pg. 12
(6) J . S . C . I . 48 325T (1929)
(7) B e r. 27 1942 (1894)
(8) Chem . A b s t r a c t s 13 314 (1919)
(9) C.A.
13 117 (1919)
(10) C.A. 16 1046 (1922)
(11)
C.A. 14 287 (1920) U.S. P a t . 1 ,3 2 2 ,5 8 0
(12) C.A. 26 P 480 (1932)
(13) C.A.
17 2277 (1923)
(14) C.A.
22 5754 (1935) B r i t . P a t . 430,572
(15) B r i t . C.A. B (1935) 796
(16) C.A. 22 4386 (1928)
(17) C.A. 30 8073 (1936)
(18)
I f o l t h o f f , I.M . and N.H. Furman V o lu m e tric A n a ly s is V o l . I I
and Sons (1929) Pg. 511
J . W iley
(19) C.A. 20 1370 (1926)
(20) See (18) Pg. 453
(21)
B r i t . C.A. A (1934) 496
C r e ig h t o n ,H .J . and W.A. K o e h le r P r i n c i p l e s and A p p l i c a t i o n s o f
E l e c t r o c h e m i s t r y V o l . I J .W ile y and Sons (1935) Pg. 290
H a n t e l l ,C . L . I n d u s t r i a l E le c t r o c h e m i s t r y Me G-raw-Hill (1931)
Pg* 83
C r e ig h t o n ,H .J . and F in k E l e c t r o c h e m i s t r y V o l . I J .W ile y and
Sons P g . 282
H o llem an ,A .F . T extbook o f Org. Chem. J .W ile y and Sons (1930)
Pg. 429

Asset Metadata

Creator Pieper, A. H. (author)

Core Title The electrolytic oxidation of benzene and its related compounds.

Contributor Digitized by ProQuest (provenance)

Degree Master of Science

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, organic,oai:digitallibrary.usc.edu:usctheses,OAI-PMH Harvest

Language English

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-788379

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Rights Pieper, A. H.

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

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