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UDC 538.33
D E T E R M I N I N G P O S I T I O N S OF S U B S T I T U E N T S IN D I S U B S T I T U T E D
PHENOLS PROM I N F R A R E D S P E C T R A
T. A. Rudol'fi
ZhurnaJ Prikladnoi Spektroskopii, Vol. 7, No. 5, pp. 698-708, 1967
This paper describes a study of the characteristic features of the infrared spectra of disubstituted alkylphenols and
terpenophenols. Since the compounds studied are trisubstituted benzenes, it was natural to use the spectroscopic rules for
trisubstituted benzenes to determine the positions of the substituents. We had at our disposal 2 ,4- , 3 , 4 - , and 2, 8-substi-
tuted phenols, or 1, 2, 4-substituted benzenes, and 2, 6-substituted phenols or 1, 2, g-substituted benzenes.
According to data in [1], 1, 2,4-substituted benzenes are characterized by an intense absorption band in the 800-860 cm -1 range, and 1, 2,3-substituted benzenes by a band in the 780-810 cm "1 range. In the spectra of the com-
pounds whict~ we studied, the ranges of absorption frequency obtained corresponded to the type of substitution in benzene. Thus all the phenols which are 1, 2,4-substituted benzenes showed an intense absorption band in the spectrum in the 800-820 cm "1 range; the phenols with the second type of substitution absorbed in the 770-78 0 cm -1 range.
Examination of the spectra in the 700-1680 cm -i range revealed characteristic frequencies for each type of substitution in phenol. The results obtained were compared with published results, which relate chiefly to alkyl-substituted phenols [2]. The characteristic frequencies for each group of phenols are given in Tables 1-4 .
According to data in [2], 2,4-substituted phenols are characterized by two intense bands in the q99-812 cm -1 range (vibrations of two neighboring nonsubstituted hydrogen atoms) and one band in the 870-890 cm -1 range (vibrations of an isolated nonsubstituted hydrogen atom). The 2,4-substituted phenols which we studied (nos. 1-11 in Table 1) are
characterized by the presence of two intense bands in the 767-800 and 810-820 cm -1 ranges, and one band in the 876-898 cm -i range. If a bulk substituent (isohexyl, nos. 8 and 7) is present in position 2, the band in the 810-820 cm "l
range is displaced tO lower frequencies (810-812 cm- l ) . A unique position in this group of phenols is occupied by 2, 4-
xylenol (no. 1), for which the second band (as in phenols, nos. 5 and 7) is displaced toward low frequencies (absorption at 808 cm-1). In the range above 1000 cm -1, the 2,4-substituted phenols show a number of characteristic bands in the
ranges (the last range in most cases shows two intense bands, possibly due to the OH-bending vibrations of the phenolic hydroxyl group), 1260-1270, and 1810-1820 cm -1 ranges. The stretching - -C=C-vibra t ions of the aromatic ring appear
in the 1608-1617 em -i range (2 ,4-xylenol in this case also is an exception, the absorption band being displaced to higher frequencies at 1626 cm-i) .
For the 3,4-substituted phenols, absorption was observed in the 784-808, 808-819, 840-855 and 860-871
c m ' i ranges [2]. For this group of phenols (nos. 12-17 in Table 2) we observed intense absorption at 810-820 and
847-864 cm-1, where there is a characteristic doublet. The OH-bending vibrations show up as intense bands (usually two) in the 1184-1210 cm "l range. The stretching --C----C-vibrations of the aromatic ring produce a doublet in the 1886-1613 cm "1 range.
The 2,g-substituted phenols were previously characterized by a single band in the 799-820 cm -i range and absorp-- tion at 889-882, 862-872, and 914-988 cm -i [2]. A similarity between their spectra and the spectra of the g,4-subst i-
tuted phenols was noted. For the phenols which we studied (nos. 18-28 in Table 8), the first intense band was found to l ie in a narrower range, i .e . 808-818 c m ' i ; this was followed by bands at 848-876 cm -1 (the 3,4-substituted phenols
have two bands in this range) and 988-967 cm "1, and a number of bands above 1000 cm -i. The stretching - C = C - v i b r a - tions of the aromatic ring appeared in the 1880-1620 cm "i range (one or two bands). 2 ,8-Xylenol , like no. 1, is an
exception.
The 2, 6-substituted phenols (nos. 29-87 in Table 4) (1,2, g-substituted benzenes) can be distinguished without great difficulty from the above phenols (1, 2,4-substituted benzenes). They are characterized by bands due to the vibra- tions of nonsubstituted hydrogen atoms, displaced toward lower frequencies; the bands lie at 786-762 and 769-781 cm -i (according to data in [2], these bands lie at 740-748 and 768-774 cm "i) and are followed by bands in the ranges
822-887, 948-964, etc. The stretching --C----C-vibrations of the aromatic ring appear in the 1889-1620 cm -i range.
The spectra were recorded with t0% solutions in bromoform (700-900 cm ~i range) or carbontetrachloride 900-1650 em -i range) on a UR-10 spectrophotometer in a fixed NaC1 cell (layer thickness 0.1 inin). It was shown by gas chroma- tography that the phenols studied had a purity of 97-100%.*
* The gas chromatography was carried out with "Twin-88" deposited on Chromosorb-W to a concentration of 10%. The temperature of the chromatographic studies varied in the i 8 0 - t 7 6 ~ range, depending on the boiling points of the phenols; the length of the column was 1-3 m, with d = 0.6 cm. A "Tsvet" chromatograph was used.
470
"fab
le
1
Spe
ci-
j %nj
8 9 10
I1
CH
a
OCH 3
OC
~H 5
OH
3
~(CH
~ 2
CH
3
/P
OCH
3
OCH
3
CH
3
CH 3
Ch
arac
teri
stic
F
req
uen
cies
o
f 2,
4-S
ub
stit
ute
d
Ph
eno
ls
Po
siti
on
s o
f su
bst
itu
ents
C
har
acte
rist
ic r
ang
es (
cm -~
, in
ten
sity
)
I ,t
767-
-800
81
0-82
0 87
5---
893
1035
---I
048
1085
--11
22
1173
120
9 12
50--
1270
CH a
CH
zCH
=CH
2
H2CH=CH z
CH
3 ,J
p C
-OH
5.
5,
CH 3 @
.~is
o is
()
~i
so
800
v.s
796
v.s
78
0 v
.s
76
7 s
76
7 s
78
8 v
.s
78
0 v
.s
790
s
792
v.s
800
reed
798
reed
80
8 v
.s
82(1
s
82
0 s
81
7 v
.s
81
2 v
.s
81
5
v.s
810
v.s
81
5 v
.s
814
v.s
81
8 s
81
5s
87
5 s
87
5re
ed
88
2 s
88
0 m
e~
89_'
2 v.
s
88
7re
ed
88
3 r
eed
89
3re
ed
89
2re
ed
~84
med
10,1
0 m
ed
1035
v.s
1048
v.s
[ 038
mea
l
10
42
med
1038
ree
d
1043
mea
l
1039
s
1039
v.s
10
38
reed
10
39
reed
llll
v.s
I 2
2re
ed
10
90
med
1097
me
1112
v.
!
1108
v.s
I 17
3 s
1274
s
I 18
3 v.
s 12
72 v
.s
1209
v.s
12
03 v
.s
1270
v.s
1 i8
2 v
.s
i25
3 v
.s
1198
v.s
I 17
8 s
1250
s
1200
s
1184
v.s
1
25
0s
1200
v.s
1180
v.s
12
45 v
.s
1204
s
1188
v.s
12
61 s
12
08 v
.s
1187
v.s
12
60 s
12
05 v
.s
1 t 8
2 s
1260
v.s
11
90 s
I t8
2 v
.s
I261
v.s
12
00 s
1310
--13
30
1608
--16
17
13
10
med
16
26 m
eal
1325
~
1612
ree
d
1327
w
1617
s
1317
s
1612
med
1328
s
1610
ree
d
13
28
v.s
I
16
16
mea
l
1330
v.s
16
16
mea
l
13
11
med
1
60
8m
ed
1315
w
1
61
0m
ed
1314
med
16
10 r
eed
13
27
s 1
61
1m
ed
Not
e:
Ab
sorp
tio
n
20
-40
%
wea
k (
w);
40
-60
%
med
ium
(m
ed);
60
-90
%
stro
ng
(s)
; an
d a
bo
ve
90%
ver
y s
tro
ng
(v.
s).
bo
Tab
le
2
Ch
arac
teri
stic
F
req
uen
cies
o
f 3
,4-S
ub
stit
ute
d
Ph
eno
ls
Spec
i- I
_r
an: ?
P
osit
ions
of
sub
stit
uen
ts
Cha
ract
eris
tic
rang
es (
cm -1
, in
tens
ity)
3 4
729-
-735
81
0--8
20
847-
-864
94
8--0
57
1003
--10
08
1020
--10
36
1103
--11
16
1184
--12
10
1248
--12
67
1586
--16
13
12
13
14
15
16
17
CH
a
CH
a
CH
a
CH
a
CH
a
CH
3
CH 3
P -CH
h,
2 c-(%
,'2 @
iso
729
med
735
w
73(
ted
73]
,ed
73',
aed
810
v.s
812
med
818
v.s
820
s
814
s
813
s
851
med
8
64
med
850
med
86
4 m
ed
847
med
8
60
med
848
med
8
60
med
855
med
I
864
med
85
2m
ed
864
med
948
s
955
s
956
954
.s
955
ed
957
1005
s
l
1005
ne
d
1008
1004
1003
s
10
22
med
1031
w
10
36
med
1033
med
1032
w
1020
med
1116
v.
s
1110
w
1108
s
1110
med
1101
w
ll0
3m
ed
1t98
v.s
12
10 v
.s
1185
s
i194
s
1188
v.s
11
98 v
.s
1184
v.s
12
00 v
.s
1200
v.
s
1188
v.
s 11
95
v.s
Not
e: A
bsor
ptio
n 2
0-4
0%
wea
k. (
w);
40
-60
%
med
ium
(m
ed):
60
-90
% s
tron
g (s
); a
nd a
bove
90%
ver
y st
rong
(v.
s).
1266
v.s
1260
s
1248
v.
s
1260
v.
s
1258
v.s
12
67 v
.s
1249
v.s
12
69 v
.s
1592
s
1612
s
1588
s
1611
s
1598
s
1612
s
1591
s
1611
s
1588
s
1613
s
1586
s
1610
s
Sp
eci-
]
%n I
18
19
20
21
22
2:3
24
25
26
27
28
Table 3
Po
siti
on
s o
f su
bst
itu
ten
ts
t 2
5 80
3--8
18
845-
-875
93
3--9
67
1031
--10
511
10
88
11
28 !
117
3--1
218
12
57
12
75
CH 3
CH
3 -C
H
ca 3
OC
H 3
CH
zCH=
CH?_
Ch
arac
teri
stic
F
req
uen
cies
o
f 2
, 8
-Su
bst
itu
ted
P
hen
ols
..
....
....
....
....
....
....
....
....
....
....
....
....
....
....
Ch
arac
teri
stic
ran
ges
(c
m -1
, in
ten
sity
)
80
8
s
81
4
s
80
t s
80
3
v.s
85
0
w
85
0
w
86
7
v,s
86
7
v.s
85
4
med
93
3 m
ed
94
7
s
96
7
s
96
7
s
95
0 m
ed
10
40
m e
d
10'1
0 m
ed
1034
s
1050
s
10
40
med
1112
s
1113
s
1118
med
o
n s
h
1093
s
1173
s
11
80
s
1218
s
1179
s
12
16
v.s
1191
med
] 2
05
med
11
82
s
12
00
s
11
79
v.
s 1
21
2 v
.s
12
75
v.s
1268
s
1276
s
} 274
v.s
OC
zH 5
CH2C
H=CH
2
(,~( C
H2 )-~
_ CH
3
OCH3
CH 3
OCH 3
~
iso
I-[.~
iso
CH a
is()
(;H
a O
CzH 5
CH
=CHC
H 3
tran
s
81
0
s
80
3
s
80
4
v.s
80
3
v.s
81
0
v.s
81
2
v.s
81
8 m
ed
No
te:
Ab
sorp
tio
n 2
0-4
0%
w
ea
k (
w);
40
-60
%
me
diu
m
86
8
med
84
7
med
87
5
s
851
med
84
5 m
ed
94
0 m
ed
94
2 m
ed
93
5
w
94
7
med
94
3 m
ed
1033
s
10
38
med
1037
v.s
10
39
med
103f
w
1048
s
1128
v.s
11
00
s
11
78
s
1214
s
10
97
med
11
80
s 1
21
2
s
1103
s
11
78
s
12
02
s
10
88
med
1
19
7
s 11
09 v
.s
12
10
s
t09
2
w
.--
1200
v.
s
med
);6
0--
90
%st
ron
g
(s);
and
ab
ov
e 9
0%
ver
y s
tru
ng
(v.
s).
12
62
--
1278
v.s
12
69
med
12
62
--
12
75
v.s
t26
7
s
1274
s
i 27
4
s
1265
med
1.10
2--1
,I,t,
I t5
80-
1620
!41
7
s ] 5
88
med
! (
528
med
14
2()
s 15
81 m
ed
16
20
s
14
22
s
....
1
60
5 r
eed
14
02
s
--
1603
s
14
15
v.s
--
16
21
s
14,1
1 s
t59
0
med
1415
med
1
61
7re
ed
14
44
s
1592
s
1418
s
15
80
med
!6
19
med
14
18
s
15
80
ree
d
16
19
med
1444
ree
d
] 58
4
S 16
18
w
d~
C,3
ga
Ta
ble
4
Ch
ara
cte
rist
ic
Fre
qu
en
cie
s o
f 2,
6-S
ub
stit
ute
d
Ph
en
ols
Spe
ci-
men
P
osit
ions
of
sub
stit
uen
ts
no
.
2
29
CH
a
30
OC
H a
31
OC
2H 5
32
OC
H a
33
CH
a
34
OC
H a
35
OC
H a
36
37
C H
a
CH 3
CH2C
H,,,C
H 2
CH2C
H=CH
2
~ ~1
,30
c-(c
h
~ li
so
@ is
o
C)
736.
-752
730
med
740
v.s
740
s
737
s
749
s
736
s
737
s
752
s
750
s
769-
-781
769
s
780
.s
78q
s
778
781
772
779
med
778
s
780
med
822-
-837
827
reed
828
v.s
825
med
823
med
837
med
873
med
822
med
822
med
833
w
Cha
ract
eris
tic
rang
es (
cm "1
, in
ten
sity
)
948-
-964
956
w
948
s
963
w
96
4m
ed
956
s
948
s
955
med
963
reed
957
ca.
1032
--10
45
1032
w
on
sh
1040
s
I03
3
w
1073
--10
88
1088
s
1080
v.
s
1079
v.
s
1041
w
10
80
v.s
10
33
med
10
78
s
1032
w
10
73
s
1045
10
40
. ~d
10
40
n
~d
1079
v.
s
1083
s
1074
med
1168
-- 1
i78
1 97
v.
s
1 85
nec
1 74
ned
1 71
ine
d
1 5
8s
1 38
:ne
d
1171
med
1168
s
1178
v.
s
1262
-- 1
274
1432
--14
52
1267
v.
s
1272
v.
s
127t
v.
s
1274
v.
s
1273
s
1272
v.
s,
1442
s
Not
e:
Ab
sorp
tio
n 2
0-4
0%
wea
k (w
); 4
0--
60
% m
ediu
m (
reed
); 6
0-9
0%
str
on
g (
s);
and
abo
ve
90%
ver
y st
ron
g (
v.s)
.
1433
s
1444
v.
s
1440
med
1442
v.
s
1432
s
1270
v
.s
1442
s
1262
s
1438
med
1268
med
14
52
v.s
1589
---1
620
15
97
med
15
95
med
16
20 m
ed
15
92
med
1
62
0m
ed
1590
med
1
61
8m
ed
15
93
med
15
89
med
1
61
4m
ed
1589
med
1
61
8m
ed
15
93
med
1590
w
The phenols were synthesized by G. I, bioldovanskaya, A. S. Podberezina, L. M. Shulov, and I. S. Aul'chenko of the Alicyclic Compounds Laboratory, and we are extremely grateful to them for kindly putting these compounds at our disposal.
REFERENCES
1. L. J. 13ellamy, The Infrared Spectra of Complex Molecules [Russian translation], IL, Moscow, p. 97, ]963. 2. D. Shrewsbury, Speetrochim. Acta, 16, 1294, 1960.
6 December 1965
475
