C H A P T E R
III
DETECTION OF UNSATURATED OHGANIC
COMPOUNDS
I n o r d e r to find the m o s t s e n s i t i v e r e a g e n t
for
the d e t e c t i o n o f m e r c u r o u s i o n s a n u m b e r o f u n s a t u r a t e d
o r g a n i c c o m p o u n d s w e r e tried (table I ) .
As a result of
this s t u d y it b e c a m e a p p a r e n t that the test f o r m e r c u r o u s
i o n s could b e r e v e r s e d an<l m e r c u r o u s n i t r a t e c o u l d be u s e d
f o r the d e t e c t i o n of u n s a t u r a t e d o r g a n i c c o m p o u n d s .
a n d c o w o r k e r s ( 1 , 2 ) i n a s e r i e s o f p a p e r s , first
Zappi
suggested
the u s e o f m e r c u r o u s n i t r a t e a s a g e n e r a l r e a g e n t for the
detection of allylic bodies and unsaturated organic
pounds,
com-
The test, however, was never extensively used
o w i n g to i t s lack o f s e l e c t i v i t y .
a t e s t i s e n h a n c e d by the fact that
The n e c e s s i t y for s u c h
tetranitromethane,
w h i c h i s a g e n e r a l r e a g e n t for u n s a t u r a t e d o r g a n i c
com-
pounds, gives a negative response with allylic bodies and
- acids, esters, aldehydes and ketones
(3).
It was,
t h e r e f o r e , d e c i d e d to e x p l o r e the p o s s i b i l i t y at' d e v i s i n g
a m e t h o d for the s e l e c t i v e d e t e c t i o n of u n s a t u r a t e d
c o m p o u n d s u s i n g the r e a c t i o n w i t h m e r c u r o u s n i t r a t e .
33
organic
As
a r e s u l t , it w a s f o u n d that i t i s p o s s i b l e to m o d i f y
the
c o n d i t i o n s of r e a c t i o n i n such a m a n n e r as to m a k e m e r c u r o u s n i t r a t e a s e l e c t i v e r e a g e n t f o r the d e t e c t i o n o f
compounds.
approach.
these
T h i s c h a p t e r s u m m a r i z e s the r e s u l t s o f s u c h a n
The p a p e r s i m p r e g n a t e d w i t h m e r c u r o u s n i t r a t e
w e r e also u s e d f o r this p u r p o s e .
34
a n d to the c e n t r i f u g a t e a r e a d d e d a few d r o p s o f 4W H N O ^
to m a k e i t d i s t i n c t l y a c i d i c ,
'ihen a few d r o p s o f a p p .
O.IM m e r c u r o u s n i t r a t e s o l u t i o n a r e a d d e d to the
A b l a c k c o l o r o r p r e c i p i t a t e s h o w s the p o s i t i v e
(3)
Test o n p a p e r ;
solution.
response.
Paper strips are impre-
g n a t e d w i t h a p p r o x i m a t e l y 0.1M m e r c u r o u s n i t r a t e
T h e p a p e r i s d r i e d i n a i r at r o o m t e m p e r a t u r e .
solution.
A
capillary
spot o f the p u r e o r g a n i c c o m p o u n d to be t e s t e d i s p l a c e d
on t h i s p a p e r .
The c o l o r i s o b s e r v e d a f t e r 5 m i n u t e s .
black to b r o w n c o l o r o f the s p o t shows the p o s i t i v e
response,
Test i s a l s o done on e l e v a t e d t e m p e r a t u r e by k e e p i n g the
p a p e r for 3 0 m i n u t e s at 60°C,
as a saturated solution in
Solid compounds are taken
ethanol.
36
A
R E S U L T S
A.
STUDIES
1*
SOLUTIONS
I n the a b s e n c e o f t h i o u r e a s ;
I n the t a b l e V I ,
given below, compounds are shown which give positive
r e s p o n s e w i t h oiercurous n i t r a t e .
with
The r e a c t i o n w a s s t u d i e d
time.
T A B L E
VI
COMPOUNDS GIVING A POSITIVE RESPONSE WITH MERCUHOUS
Compounds
Allyl
Time
alcohol
immediately
Cinnamyl alcohol
30 minutes
Geraniol
1 minute
Farnesol
5 minutes
minutes
Crotonaldehyde
Acetyl acetone
1 minute
A s c o r b i c acid
immediately
Acetoacetic
immediately
Cyanacetic
ester
ester
3 minutes
37
NITRATE
The f o l l o w i n g o r g a n i c c o m p o u n d s did n o t show a
p o s i t i v e r e s p o n s e e v e n i n 60 m i n u t e s :
ALCOHOLS:
Methyl, ethyl, propyl, isopropyl, n-butyl,
isobutyl, tert-butyl, amyl, tert-amyl, octyl, benzyl and
cyclohexanyl
pylene
a l c o h o l s , g e r a n i o l , e t h y l e n e glycol
and pro-
glycol.
ALDEHYDES:
Formaldehyde, acetaldehyde, benzaldehyde,
chloral, salicylaldehyde, resorcylaldehyde and o-nitrobenzaldehyde.
KETONES:
Methyl ethyl, methyl n-propyl and methyl iso-
propyl ketones, acetone, acetonyl acetone, acetophenone,
c y c l o h e x a n o n e , a n t h r a q u i n o n e a n d ^(s-amino a n t h r a q u i n o n e .
ACIDS:
formic, acetic, propionic, butyric. Oxalic, tartaric,
citric, mucic, cinnamic, lauric, myristic,
camphoric,
stearic, m-nitrobenzoic, benzoic, salicylic and phthallic
acids.
ESTERS:
M e t h y l , e t h y l , a m y l , and m o n o - b r o m o e t h y l a c e t a t e s ;
e t h y l , a m y l , and e t h y l p - a m i n o b e n z o a t e s , e t h y l
IS-
formate,
diethyl oxalate, ethyl acetone dicarboxylate, diethyl
m a l o n a t e , dimethyl sulfate, and ethyl n i t r a t e .
A M I N E S A N D AMIDESt
M e t h y l , d i e t h y l , and d i p h e n y l amines-,
dimethyl, diethyl, and chloro anilines; p y r i d i n e , benzidine,
p-anisidine, acridine; formamide, acetamide and urea.
CARBOHYBHATBSi
and
D-gluoose, fructose, lactose, dextrin,
raffinose.
AHHYDRIDES AHD ACID CHLOHIDES;
benzyl
Acetic anhydride, and
chloride.
HYDROCAKBOSS AHD SUBSTITUTED HYDROCAHBOKS:
cyclohexane, nitrobenzene, chloroform,
Hexane, toluene,
tetrahydrofuran,
carbon tetrachloride, carbon disulfide, arsenobenzene,
acenaphthene, anthracene.
PHENOLS;
P h e n o l , a m i d o p h e n o l , p - a m i d o p h e n o l , amido
p h e n o l p - c h l o r o h y d r a t e , o6-naphthol,y^-naphthol, d e c a hydro transbeta naphthol, pyrogallol, resorcinol, catechol,
and pyrocatechol.
39
MiSCELLAtfgQUai
tro-naphthalene, diacetyl, azobenzol,
c a f f e i n e , k e r o s o l , c a s e i n , c o n g o r e d , 2:4
dinitrophenyl
h y d r a z i n e , d i p h e n y l c a r b a z i d e , d i m e t h y l glyoxiiBe, b o r n e o l ,
ethylene bromide, pbenolphthalein, ethylene dibromide,
ethylene urethane, alizarin-S, cholesterol, and methylal.
B«
S T U B I E S O H P A P E K S IIIPiiEGHATEP i^lTH M E R C U H O U S W I T K A T E
Impregnated papers with mercurous nitrate were also
u s e d f o r the d e t e c t i o n of u n s a t u r a t e d o r g a n i c
compounds.
T h e r e s u l t s are s u m m a r i z e d b e l o w :
1.
Compounds giving positive response at room
temperature and at
Alcohols:
Amines:
60^G.
Allyl alcohol
D i e t h y l , m o n o e t h a n o l , and
diethanol
amines.
Acids:
Ascorbic
Thioureas:
acid.
A l l y l , d i p h e n y l , 0 - t o l y l , and symisopropyl thioureas;
/.o
thiourea.
2.
Coinpounds g i v i n g n e g a t i v e r e s p o n s e at r o o m
t e m p e r a t u r e b u t p o s i t i v e r e s p o n s e at
elevated
temperature;
Alcohols:
Acids;
Geraniol
Formic a c i d .
Aldehydes?
F o r m a l d e h y d e (10 m i n u t e s ) and
acetaldehyde.
Amines:
Diethyl
aniline
Esters;
Ethyl formate and ethyl acetoacotate.
Compounds ^ v i n ^ negative response both at room
temperature and elevated
Alcohols;
temperature;
Methyl, ethyl, propyl, isopropyl,
n-IXutyl, i s o b u t y l , t e r t - b u t y l , a m y l ,
t e r t - a m y l , o c t y l , c i n n a m y l , a n d cyclohexanyl alcohols; ethylene
glycol,
p r o p y l e n e g l y c o l , and g l y c e r i n e .
Aldehydes;
F o r m a l d e h y d e , a c e t a l d e h y d e , crotonaldehyde, benzaldehyde, chloral,
41
salicylaldehyde, vanillin, nitrobenzaldehyde, and
Acids;
trithio-formaldehyde.
Acetic, propionic, butyric, oxalic,
tartaric,
citric, capric, mucic, cinnamic, lauric,
myristic, camphoric, stearic, benzoic,
salicylic, phthallic and nitrobenzoic
acids.
E s t e r s ; M e t h y l , e t h y l , a n d monobroaio e t h y l a c e t a t e s ?
e t h y l and d i e t h y l malonates;, e t h y l
and diethyl
Ketones;
formate
oxalate.
Methyl ethyl and methyl n-propyl Ketones;
a c e t o n e , a c e t o n y l a c e t o n e , and borizophenone.
Amines;
Ethyl aniline, rosaniline, triethanol a m i n e ,
and
Thioureas;
o-tolidine.
o^-naphthyl
42
thiourea.
D I S C U S S I O N
Two b a s i c m o d i f i c a t i o n s m a d e i n Z a p p i ' s m e t h o d
for
the d e t e c t i o n of u n s a t u r a t e d o r g a n i c c o m p o u n d s are a s
follows:
a.
Lowering of pH and
t).
L o w e r i n g of
temperature.
W h e n the r e a c t i o n i s p e r f o r m e d i n a c i d i c m e d i u m
s u b s t a n c e s like a m i n e s do n o t give a p o s i t i v e
with mercurous nitrate.
reaction
I f the r e a c t i o n i s p e r f o r m e d a t
r o o m t e m p e r a t u r e a l a r g e n u m b e r o f o r g a n i c c o m p o u n d s do
not give this test.
The only interference remains from
t h i o u r e a s w h i c h g i v e a p o s i t i v e test e v e n a t low
a n d low p H ,
temperature
T h e r e f o r e , the i n t e r f e r e n c e f r o m these c o m -
p o u n d s i s r e m o v e d by c o m p l e x f o r m a t i o n w i t h m e r c u r i c
nitrate.
I f t h i o u r e a s a r e p r e c i p i t a t e d by the a d d i t i o n o f m e r c u r i c
n i t r a t e the r e a c t i o n b e c o m e s f a i r l y s e l e c t i v e .
o f time o n the r e a c t i o n w a s a l s o s t u d i e d .
The e f f e c t
It was found
that o f the a l l y l i c a l c o h o l s t e s t e d the s i m p l e a l l y l
a l c o h o l g i v e s a p o s i t i v e test i m m e d i a t e l y w h i l e the s u b s t i tuted a l c o h o l s take a l i t t l e m o r e t i m e .
43
It is thus possible
to d i s t i n g u i s h b e t w e e n the a l l y l i c a l c o h o l s as a r e s u l t o f
this reaction.
This r e a c t i o n i s a l s o u s e f u l i n d i s t i n g -
u i s h i n g between malonic ester and acetoacetic ester.
using a
a l c o h o l i c s o l u t i o n n o test i s o b t a i n e d
Thus
with
m a l o n i c e s t e r w h i l e a fairly p o s i t i v e r e s p o n s e i s o b t a i n e d
from a c e t o a c e t i c e s t e r .
T h i s may be e x p l a i n e d on the
a s s u m p t i o n that it i s the e n o i i c f o r m o f the e s t e r w h i c h
r e a c t s w i t h the m e r c u r o u s i o n s .
H o w e v e r since m a l o n i c
e s t e r e x i s t s m o s t l y i n the k a t o n i c s t a t e h e n c e it d o e s n o t
give a positive response.
A c e t o a c e t i c e s t e r , on the o t h e r
h a n d , e x i s t s i n e n o i i c form to a m u c h g r e a t e r e x t e n t
and hence gives a positive test.
(7^)
O f the c o m m o n a c i d s
o n l y a s c o r b i c a c i d gave a p o s i t i v e r e s p o n s e .
tried
Therefore,
this m e t h o d c a n be u s e d for the s e l e c t i v e d e t e c t i o n o f
ascorbic acid also.
A s c o r b i c a c i d c a n be c o n s i d e r e d a s an
unsaturated alcohol ana its positive response with mercurous
n i t r a t e c a n t h e r e f o r e be e a s i l y e x p l a i n e d , M e r c u r o u s
nitrate
paper also offers interesting possibilities. Thus if a
s u b s t a n c e does n o t c o n t a i n N a n d S a n d g i v e s a p o s i t i v e
r e s p o n s e w i t h m e r c u r o u s n i t r a t e p a p e r i t s h o w s the p o s s i b i l i t y o f a l l y l a l c o h o l and a s c o r b i c a c i d .
p o s s i b l e to d i s t i n g u i s h
Similarly it is
c^-naphthyl t h i o u r e a from o t h e r
c o m m o n t h i o u r e a d e r i v a t i v e s since i t g i v e s a n e g a t i v e
44
test
b o t h a t o r d i n a r y t e m p e r a t u r e a n d at 60°C*
Formic acid i s
the o n l y a c i d w h i c h g i v e s a p o s i t i v e r e s p o n s e at 60®C a n d
no r e s p o n s e at o r d i n a r y t e m p e r a t u r e *
T h i s m e t h o d can
there-
fore b e u s e d for the d e t e c t i o n o f forjnic a c i d i n o t h e r a c i d s .
45
UTERATUKE
CITED
1.
E . V . Z a p p i , B u l l . S o c . Ciaim..
2.
E . V . Zappi a n d A . T . W i l l i a m s , i b i d .
3.
L . F . H e s e r and M . ileser, "Steroids", p . 175,
H e i n h o l d Pub, C o r p . N . Y . ( 1 9 5 9 ) .
4.
I . M . Kolthoff and W.D. Larson, J . A m . Chem. Soc., 56,
1881 ( 1 9 3 4 ) .
5«
I.M. Kolthoff and N,H. Furman, "Potentiometric
T i t r a t i o n s " , II E d . p . 1 7 7 , J o h n Wiley & S o n s , I n c . ,
Hew Yoric ( 1 9 4 7 ) .
46
54
(1952).
1258
(1932).