Detection and Spectrophotometric Determination of Organic Functional Groups With Special
Reference to Carbonyl Compounds
M. Phil. Dissertation
AHSAN SAEED
Department of Chemistry Aligarh Muslim University
Aligarh-202001 (India) 1 9 8 6
\ 1
f6 ^'••i t/- „•) 1^ r.f-
DS906
C O N T E N T S
ACKNOWLEDGEMENT
ABSTRACT
Page No
( i ;
( 11 ;
CHAPTER - I Introduction
References
1
6
CHAPTER - II A sensitive and selective spot test
for the detection of methyl or
methylene ketones
Introduction
Experimental
Discussion
References
8
10
15
19
•••••
ACKNOWLEDGEMENT ^
It is always a pleasant task to acknowledge one's debt
I am deeply obliged to Dr. Saidul Zafar Qureshi for his kind
and encouraging supervision which has made this study possible
I am grateful to Professor M.S. Ahmad, Chairman,
Department of Chemistry, Aligarh Muslim University, Aligarh,
for providing research facilities.
I am also obliged to my loving mother for constant
encouragement and her interest in my academic pursuits.
Last but not the least I wish to thank all my research
colleagues for providing me a congenial company and
maintaining a cordial atmosphere in the laboratory.
Cfe:^ ( AHSAN SAEED J
( i i ;
ABSTRACT
This dissertation comprises of two chapters. In the first
chapter, a detailed and upto date literature survey of subject
have been reviewed.
The second chapter includes the sensitive and selective
spot test for detection of methyl or methylene ketones. Ketones
are simplest organic compounds containing the carbonyl groups o
( R-C-R ) . In ketones molecules, both attachment to carbonyl
are alkyl or aryl groups. In this chapter a spot test for the
detection of methyl or methylene ketones is based on the reaction
with sodium nitroprusside in the presence of ehtyl amine, to give
a red colour. Put 2-3 drops of ethyl amine with few drops of
sodium nitroprusside on a white spot plat. Add 1-2 drops of test
solution. A red colour developed with in one minute indicates a
positive test of ketones. The following ketones gave a positive
test I ehtyl mehtyl ketone, acetone, methyl propyl ketone, diethyl
acetone, acetyl acetone, methyl pentyl ketone, hexyl methyl
ketone. The following organic compounds when treated by the
recommended procedure were found to give the characteristic
colour which are indicated in the paranthesesi resorcinol
( green ), indole ( blue ) , piperidine ( red ) , cyclopentanone
( red ) , cyclohexanone ( red ) , ethylactoacetate { red ) ,
diethylmalonate ( yellowish-red ) .
( i i i )
A negative test was obtained by the following functional
groups ', sugars acids, amino acids, nitriles, amides,
aldehydes, esters, phenols, hydrocarbon and their derivatives.
The limit of identification of methyl or methylene ketones
and detection in the presence of foreign substances were
studied .
CHAPTER - I
INTRODUCTION
A nijunber of test for the detection of ketones have been described
by the Fiegl C 1 J, Acetone gives the intense red-yellow colour
which changes to pink-violet on acmfying with acetic acid when
treated with sodium nitroprusside in the presence of alkali. The
basis of this colour reaction is that NO of nitroprusside react
with acetone to give isonitrosoacetone, which remains in the anion
complex. At the same time FeClIIj reduced to FeClIJ .
-2 C Fe (CN;5 NO 1 + CH2COCH2+ 2 OH
-4 C Fe (CNjg ON = CHOCH^l + 2H^0
In another test 0(- substituted ketones are treated with 5- amino-2, 3-
dihydroxy-1,4- phathazinedione and hydrogenperoxide to give
chemilximinescence ( 2 J . A sensitive and selective condensation
reaction to detect the ketones is dimodone test ( 3 ). Dimodone
( 5,5- dimethylcyclohexanone-1,3- dion ) react with most ketones to
yield a crystallized product. Identification of ketones can be
carried out after isolation of crystalline product on the basis of
their composition and melting point.
HgC CHg
^CH3)2=C^ /=0 C H2
"1 I
0 = C I R2
-H9O
R, R2 ' \ / ^
HoC CH ur CHo II ""? I
(CH-,)oC C = 0 0 = C C(CH3)_ C C H2 H2
0 II
R, R2 \ /
c c c / \ / N. / \
Hj>C C C CH2 I )i II I
•HoO Boil
(CH3)5C C C C(CH3)2 c c c H2 ^2
a and f- diketones ( 4 ; can be detected after reaction with 0-
phenylenediamine. The sample is dissolved in water or ethanol and
an acidic solution of phenylenediamine is added to get suspended
precipitate. The tube is immersed into a hot water bath. The
suspention of precipitate washed with water has an acid-base
character and turns violet in the presence of base. With a-
diketones, a few crystals of the sample are added to the solution,
a violet colour is obtained and becomes intense as the crystals
are dissolved.
NH2
NH;
0=C-Ri
0=C-R.
fl
+ 2H2O
Whereas f- diketones form heptazine accordingly to reaction.
V' NH2 0 =C 1
a + CH2
NH2 0 = C — R2 H N - C - R,
1
+ N = C H
CH ics
N =C -R I CH2
N =C —R,
N = C- Ri I
CH I
N =C - Ro H
H
Sawicki and coworkers C 5 ) has described a novel test for the
detection of aryl alkyl and dialkyl ketones. The sample is
dissolved in one drop of dimethylformamide and treated with 1% 2,2-
dinitrophenol dissolved in dimethylformamide. To this one drop of
105i tetraethylammoniumhydroxide is added. A violet or blue colour
appears. In another test ketones can be detected in the presence
of aldehydes, after oxidation with peroxytrifluoacetlc acid. Only
ketones are converted into esters or lactones, which are detected
by the well known hydroxamic test { 6 ) , Fiegl C 7 ) has described
two spot tests reaction for vicinaldiketones and o- dioxoketones.
When a mineral acidic solution of phenylhydrazine is added to give
a yellow colour product. Some aromatic and a- unsaturated
aldehydes interfer with test by forming a similar colour. Second
test is based on condensation product of ammonia and formaldehyde
which react to produce a redish-violet colour with citric acid and
acetic anhydride. Tertiary amine interfer with the test.
2- diphenylacetyl-1,3- indandione-1-hydrazone have been used
by Braun and Mosher ( 8 > as a reagent for identifying and
characterising carbonyl compounds. It react with aldehydes or
ketones in the presence of acid catalyst to give mixed azines.
0' ^
i ; 1
II N - NH2
0
RCR + H
R = H for aldehydes
-H..
0 li
C—CCH(C6H5)2
II R N — N s C ^ /
^ R
Another test of carbonyl compounds is based on the use of
N- ( 2-acetyl-l, 3-indanedione-l-hydrazone ) trialkylammonium
iodies. Aldehydes, ketones, ketoacids, cyclic ketones are
successfully detected in the presence of iso-propyl alcohol ( 9 }
Legardi ( 10 ) has reported a general method for the detection
of oxo-compounds containing carbonyl methylene or acylhydraside
group and which form enols. A simple rapid method have been
described by Cross and Swann ( 11 ; for the detection of esters,
alcohols, ketones in paint thinners and solvents at low concentra
tion as low as 1% by using thin layer chromatography. Diphenyl-
hydrazine have been used by Aleksandra ( 12 J for the detection and
determination of halo-ketones. James ( 13 J has reported the use
of Bordwell- wellman reagent ( chromic anhydri,de in dilute sulphuric
acid ) to distinguish aliphatic aldehydes from aromatic aldehydes
and aldehydes from ketones. Another test for aldehydes and ketones
is based on the condensation of salicylohydrazide to give intense
fluorescence ( 14 ;, Sawicki and Thomas ( 15 ^ have developed a
sensitive test for the detection of aliphatic ketones. Halogen-
cobalt (II J acetic acid solution have been used by Philips ( 16 j in
qualitative analysis of oxygenated compounds such as aldehydes,
ethers and ketones. Ketonic compounds ( 17 ) have been detected by
oxidation with trifloroacetic acid, yielding esters or lactones.
The resulting oxidation product are detected with ferric hydroxomate
to give a characteristic purple red colour. However unsaturated
aldehydes ( crotonaldehyde and cinnamic aldehyde ; interfere with
test, A general test for carbonyl compounds have been proposed by
Asaka C 18 ;.
Ion exchange resin beads have been successfully used as a
detection media for a number of organic functional groups ( 19-24 ).
Qureshi et al, extended the use of ion exchange resin as a reaction
medium for the detection of ketones, which react with l-chloro-2,4-
dinitrobenzene in the presence of anion-exchange resin in OH" form
to give a violet colour on resin beads surface. The reaction
mechanism is cited below.
In basic medium there is a reversible addition of OH" to
carbonyl group.
CH
CH3
\ I C = 0 + OH
CH, O" \ /
•c / \ CH- OH
The anion produced act as a nuclophile and add at the
reagent carbon-atom bearing chloride atom, the reaction being
promoted by the presence of nitro group.
CH3 O \ / C 4 CI-
/ \ CH3 OH
// V NO2
NO2
NO2
Dutt ( 26 ) has described a new variety of dye reagent for
the detection and identification of alcohols, aldehydes, ketones,
amines and ethers.
REFERENCES
1. F. F€i'gl/ Spot test in Organic Analysis, 6th Ed., P. 236-237,
Elesvier Amstardam, ( 1960 ) ,
2. H.W. Yurow and S. Sass, Anal. Chim, Acta, 68, 203-4, ( 197 4 ;.
3. L. Mazor, Method of Organic Analysis, Vol. XV, p. 163, Elesvier,
Amastardam, ( 1983 ) .
4. L. Mazor, Method of Organic Analysis, Vol. XV, P. 164, Elesvier,
Amstardam, ( 1983 J.
5. E. Sawicki, J. Neo, T.W. Stanely, Mikrochimica Acta, 286, ( 1960 ;
6. R. Bruckner and J.M. Rosen, Anal. Chem., 33, 273, ( 1961 ;.
7. F. Feigl, L. Ben-Dor, S. Yariv, Israel J. Chem., 2, 139, ( 196 4 ;,
Ref. Anal. Abstr., 13, 4189, (196 4 ) .
8. R.A. Braun and W.A. Mosher, J. Am. Chem. Soc, 80, 3048, ( 1958 ).
9. M.K. Bachlaus and K.L. Menaria, Talanta, 20, 420-2, ( 1973 ) .
10. L. Legardi, Mikrochim acta, 4, 583-93, ( 1973 ;.
11. C.W. Cross and M.H, Swann, Res. Develop. Rep., 69, 102, ( 1969 ).
12. A. Stachlewska-Wroblowa, Chem. Anal., (Warsaw;, 11, 1099-104,
( 1966 ) .
13. D.M. James, J. Chem. Educ, 42, 142-8, ( 1965 ;.
14. B. Camber, Nature, 174, 1107, ( 1954 ) .
15. E. Sawicki, and W. Thomas, Anal. Chem., 31, 122-4, ( 1959 ) .
16. P.C. Daidone, Anal. Chem., 27, 103-4, ( 1955 ;.
17. R. Drucker and M.J. Rosen, Anal. Chem., 33, 273-5, ( 1961 ;.
18. Y. Asaka, K. Numata, M. Susuki and S. Takitam, Bansuki, Kagaku,
24, 106, ( 197 5 J .
19. M. Qureshi and S.Z. Qureshi, Anal. Chim. Acta, 34, 108, ( 1966 ) .
20. P.W, West, M. Qureshi and S.Z. Qureshi, Anal, Chim, Acta, 36,
97, ( 1966 ;.
21. M. Qureshi, S.Z. Qureshi and N.Z. Zehra, Anal, Chim. Acta, 47,
169, ( 1969 ) .
22. M. Qureshi, S.Z. Qureshi and S.C. Singhal, Anal, Chem., 40,
1781, ( 1968 ) .
23. S.Z. Qureshi, M.S. Rathi and S. Bano, Anal. Chem., 46, 1139,
( 197 4 ) .
24. S.Z. Qureshi and M.S. Rathi, Anal. Chem., 47, 1424, ( 1975 ) .
25. S.Z. Qureshi and Izzatullah, Talanta, 24, 529-30, ( 1977 ).
26. M.K. Dutt, Sci. Cult., 50, 158-61, ( 1984 ).
CHAPTER - I I
A SENSITIVE AND SELECTIVE SPOT TEST FOR THE
DETECTION OP METHYL OR METHYLENE KETONES
8
A number of tests have been described for the detection of
ketones. However, these test are not selective to detect ketones
in the presence of aldehydes. Aldehydes also give the typical
reaction of ketones. Aliphatic ketones are detected with salicyl-
aldehyde in the presence of concentrated sulphuric acid. The
colour may vary from orange red to violet and depends on the length
of carbon chain. The reaction is not specific to ketones, as some
high molecular weight carboxylic acids, esters, and all canpounds
that contains the - CH2 - CO - CH, - group also react ( I K The
reaction between methylene ketones with sodixjwi nitroprusside in
the presence of alkali gives an intense yellow colour which turns
violet in the presence of a acetic acid i 2 ) , An alkaline solution
of sodium nitroprusside is colourless when acetic acid is added.
This basis of this colour reaction is due to isonitrosation of
methylene ketone group ( - CH_CO - ) . This test fails with ketones
in which no methyl or methylene group is attached to Oxo- group.
Moreover a large number of compounds other than ketones give a
positive test. A detailed account to this effect has been explained
in this discussion, A new spot test for detection of aliphatic
aldehyde and ketones is based on the interaction with 2,3- dimethyl-2,
3-bis ( hydroxyamino ; butane to form anhydro product which is
converted into intensely coloured stable nitronyl nitroxide free
radical on addition of sodiumperiodate C 3 J. Another spot test
has been described by Bajaj ( 4 ; for detection of aldehydes and
ketones which gives yellow to r d colour on treatment with ethanol
amine containing a small amount of acetic acid. Sawicki ( 5 ) has
described a test for acetonyl compounds, based on the thermochromic
reaction with 2-hydroxy-l-naphthaldehyde to produce a brilliant
green colour. Acetophenone/ heptanone, and pentanone give a
negative test. A general test is based on its interaction with
pentacyanoaquoferrate to produce a red colour ( 6 J. Another test
for aliphatic ketones described by Anger { 7 ^ is based on the
use of alkaline m-dinitrobenzene as a condensation reagent.
10
E^ERIMENTAL
All chemical were of reagent grade.
256 ( W/V ; Sodium nitroprusside solution was prepared in
distilled water.
Pure ethyl amine ( 12.24 M ) was used as such.
1% ( V/V ; ketones solutions ( ethyl methyl ketone, acetone/
methyl propyl ketone, diethyl acetone, acetyl acetone ; were
prepared in distilled water.
A 1% ( V/V ) methyl pentyl ketone and hexyl methyl ketone
solution were prepared in alcoholic-water mixture in the
ratio of ( 213 ) respectively.
Procedure
Put 2-3 drops of ethyl amine with a few drops of sodium
nitroprusside on a spot plate. Add 1-2 drops of sample
solution. A red colour developed within one minute if
the test solution contains ketone.
Result
The following ketones gave a positive test ; ethyl methyl
ketone, acetone, methyl propyl ketone, diethyl acetone.
11
acetyl acetone, methyl pentyl ketone, hexyl methyl ketone.
The following organic compounds when treated by the
recommended procedure were found to give the characteristic
colours which are indicated in psirantheses ', resorcinol
( green ) , indole ( blue ), piperidine ( red ) , cyclohexanone
( red ) , cyclopentanone ( red ) , ethylacetoacetate ( red ) ,
diehtylmalonate ( yellowish-red ) .
The following typical organic compounds gave a negative test,
SI
Sugars I Glucose, fructose, sucrose, rhmnose.
Acids ', Acetic acid, formic acid, ascorbic acid, oxalic acid.
Aldehydes I Acetaldehyde, benzaldehyde, 4-diaminobenzaldehyde.
Amino acids I Glycine, leucine, lysine, tryptophane.
Nitriles I Acetonitrile, benzonitrile, propionitrile.
Amides '. Acetamide, benzamide, N-N dimethylformamide,
Esters '. Ethyl acetate, methyl acetate, methyl oxalate.
Phenols '. m-bromophenol, m-cresol, phenol, orcinol.
Alcohols '. Ethyl alcohol, methyl alcohol, iso-amyl alcohol,
butyl alcohol,
Hydrocarbon and their derivatives I Benzene, xylene,
chloroform, toluene.
The limit of identification for a number of ketones was
determined. The results are siommarized in table - I.
12
Detection_of_ketones_in_the_gresence__of^forei2n^substances
The detection of ketones in the presence of foreign
substances was studied. Acetyl acetone was taken as a
representative of ketones, The maximum amount to be
tolerated of foreign substance in the minimum
detectable amount of ketone is given in the table - II,
Stud^ of charge on complex
The study of charge on the complex was determined by
adding two type of resin,
(a Anion exchange resin.
(b) Cation exchange resin.
The anion exchange resin turned red, as they are
exchange by negatively charged complex.
13
Table - I
Limit of identification of methyl or methylene ketones
Ketones Percent Conc.(V/V; Volume taken Amovmt detected (ml-j (mg)
Ethyl methyl ketone
Methyl propyl ketone
Methyl pentyl ketone
Acetone
Acetyl acetone
Diethyl acetone
Hexyl methyl ketone
1
1
1
1
0.25
1
1
0.03
0.025
0.025
0.015
0.005
0.03
0.02
0.24
0.20
0.20
0.12
0.048
0.24
0.164
14
Table - I I
De tec t ion of a c e t y l ace tone i n t h e p re sence of fo re ign subs tances
Foreign subs tances Amount of fo re ign Amount of a c e t y l acetone subs tance added d e t e c t e d
Img; (rag;
Sucrose 0 .40 0.048
A c e t o n i t r i l e 0.312 0.048
Formamide 0.452 0.048
Ethyl a c e t a t e 0.186 0.048
Ethanol 0 .314 0.048
Urea 0 .40 0.048
Leucine 0.30 0.048
15
DISCUSSION
The tentative reaction mechanism of the recoiwnended test
involves in three steps. First, methyl or methylene ketones are
catalysed into enolisation by weakly bases ( Kb values lies in -3 -5
the range 10 -10 ) with net result of removal of proton from
a- position to give a considerably stabilised enolate anion
with substantial proportion of the negative charge on oxygen
atom. The hydrogen, alpha to carbonyl group has acidic
character ( 8 K
CH^ - C - CH^ : H + : NH^R ^ CH^ - C = CH^ + H"
enolate anion
? ? O CH^ - C = CH^ - CH^ - C - CH2 :
Secondly the isonitrosation of "•CH2- group by the NO of
nitropirusside is involved ( 9 ) forming an unstabilised complex
in which iron is in its reduced form. At the same time the
proton are picked up by the amines to form positively charged
spec ies .
0 II ' - 2 - 4 ,
CH - C - CH2: + C F e CCNJ5ON ) > C CH3COCH = NOCCNj^Fel + H"
2H'*" + 2NH2R > 2RNH2
Finaly, the highly negatively charged anionic species are
c-pable of forming relatively stable ion-pairs with positively
charged species of amines ( 10 ).
16
- * 4.
[ CH^COCH = NO (CNjg Fe 1 + 2RNH^
i -2 C CH cocH = NO (CN;^ Fe 1 . 2RNH2
Ion - pair formation ( R»d )
Some derivative of Cbrboxylic acid containing the
-CH^-CO-CH - group give a positive test. Pertenant examples
are Cyclohexanone and Cyclopentanone. The activation of
methylene group by the base is attributed as follows
II r I + II
H2C CH2'^ : N H 2 H2C CH H2C CH
< ^ I 1 -< ^ I I + ^ H g C ^ CH2 H 2 C . / C H 2 HgC CHg
^ C C C ^ H2 H2 H2
Esters of caboxylic acid which contain carbonyl group give
dark yellowish red colour which can be distinguished and therefore
there is no interference with the text. In sujrh compounds the
carbonyl group get enolized to produced the characteristic colour
other than red.
- CH^CO - ^ - CH = C -
OH
Compounds which contains an activated methylene group or In
which an active methylene group can arises through the shifting
of a hydrogen atom are found to be give a negative test. Examples
are indene, indole, and resorcinol (which produced characteristic
colour other than redj. Piperidine was the only compound which
17
was found to interfere with the test. It contained a methylene
group and have a moderately basic character ( Kb - 10 ;. The
positive test can not be attributed due to the presence of
methylene group. The electron pair of nitrogen in piperidine
molecule in association with the pair of N-atom of amine group
(both acting as bases; might be responsible to-activate the
methylene group of piperidine molecule as follows.
H2C CH2 /^ ^ : N H 2 HgC CH2
H 2 C . ^ . . / C H 2 H 2 C ^ CHg
^ N NH2 H
Fiegl test is not specific for ketones, as some high
molecular weight carboxylic acids, esters and all ccxnpounds that
contains the -CH -CO-CH - group also react. Moreover ccsnpounds
with carbonyl group capable of enolisation also give a positive
reaction. A large number of compounds containing methylene
group or in which an active methylene group can be induced by
shifting a hydrogen atom also interfere the test i.e, indene,
pyrrole, indole, resorcinol, cyclohexanone, cyclopentanone,
orcinol, hexylresorcinol, phloroglUcinol, malonic diethyl ester,
cyanoacetic ethyl ester, vitamin-C, digitoxin, pyrrole, indole
acetic acid, phenylisocrotonic ethyl ester.
The basis of behaving the present test is selective, can
be explained as follows. • \ ''-^"'-^^^^^%
18
In Fiegl's test a concentrated solution of sodixoin hydoxide
( 30% W/V ; was used which was highly basic as compared to an
-5 -3 amine group with Kb-10 -10 and therefore acted as a strong
nucleophilic reagent to abstract a proton and to form an
undissociated water molecule, leaving behind the medium still
strongly alkaline.
H"*" + OH" •' ' H-0 + OH"
Excess
The formula of
-4 C Fe (CN;. ON = CHCOCH. 3 + OH" still in excess.
In the case of amine the proton so released combined with
amine to form a positively charged species which interact with
highly negatively charged species to form a relatively stable
ion-pairs red complex, thereby stabilizing the energy (a point
of difference with Fiegl test that is the same methylene ketonic
compounds produces different types of colour).
19
REFERENCES
1. F. F-eV-gl, Spot test in Organic Analysis, 6th Ed., P. 236,
Elesevier, Amsterdam, ( 1960 ) .
2. L. Mazor, Method of Organic Analysis, Vol. XV, P. 163-6 4,
Elesevier, Amstardam, ( 1983 ) ,
3. J.W. Munson and T. Hodkins, Microchem,J., 20, 39, ( 1975 ).
4. K.L. Bajaj, Talanta, 23, 77, ( 1976 ) .
5. E. Sawicki, Chemist. Analyst., 4§, 4, ( 19 59 J .
6. Zu-Hua Huang, Hua Hsuch Tung Pao., 6, 3 47, ( 197 5 ) .
7. V. Anger and S. Ofri, Z. Anal. Chem., 206, 186, ( 196 4 ;,
8. J.D. Roberts and M.C. Caserio, Basic Principles of Organic
Chonistry, P. 475, W.A. Benjamin, Inc. New York, ( 1965 ) ,
9. F. Felgl, Spot test in Organic Analysis, 6th Ed., P. 236,
Elesevier, Amstardam, ( 1960 ) ,
10. B.L. Wedzioha, Chemistry of Sulphur Dioxide in Foods,
Elesevier, New York, ( 1984 ; .
