Samples were admitted bv a calibrated micropipet, using the technique described by Taylor and Young.8 Sample pressures were computed t o be between 5 and 50 X mm. at the capillary leak, which was located inside the ion source. (8)R. C. Taylor and W. S. Young, Ind. Eng. Chetn., A n a l . E d . . 11,
Samples of the acids used had boiling points and refractive iridiccs as shown in Table 111. The formic acid was Eastman Kodak Co. white label material, not further purified. We are indebted t o C. F. H . Allen and L. B. Genung, for arrarlging for the purifications and syntheses* ROCHESTER, N. Y.
811 (1945).
[ CO\TRIBUTIO\
PRO11 THE s A I I O Y 4 L K E s F A R C H c O O \ C I I .
(C4\
4D4l
I
The Infrared and Raman Spectra of p-Dioxane BY F E. MALIIERBE' ASD H. J. BERNSTEIK RFCEIVEDDECEMBER 26, 1951 The infrared spectrum of liquid p-diouane has been ol)taliiecl from 2 5 37 p and three new fuiidamental~were observed Reinvestigation of the Raman 5pectruni gave one iiew fundanicntal A trntdtibr abzignrrient of a11 vil,ratiorial modes has been made and the specific heat calculdted at several tetiiperdture5
In the course of investigating complex formation with p-dioxane by spectroscopic methods we ohTABLE
ASSIGNMRNT OF
T H E I'USDAXESTAL.5 I N p - I l I O X A S E
lkwriptiou of vibr;ltion
CI'I stretchitig
'I\
U: J
Ileformatinn Twisting If-agging Rocking
VJ
V, P,
V6
vi V3
Ring stretchiiig
]
"' VI0
Ring bending
~ 1 1 1 Yl2j
CIT stretching
ui3
T)eformatiori Twisting \l.aggiiig Rocking Ring stretching
U I ~
uij VI6
VI7 \
'I8) ui9,
;'02' U?1, YX
u?3 YX Y?S uz6)
Ring bending
C I I stretching Deformation Twisting \Vagging Rocking Ring stretching
V27
R,
I
tained the infrared spectrum of p-dioxane in the liquid, solid and gas phase and the Raman spectrum of the liquid. The infrared spectrum of the liquid and gas had been obtained previously2s3from
Ring bending
This work
Biirket" and Badger
TABLE I1 SPECTRUM O F 1,IQUID P - D I O X A N E
Kelative'
2966 28X5 1443
I308 112;
RAalAN
Rarnsnyh
wrn
17Sd
130,?
241"
iiiteos- Polariitp 7:itionb
1014 83.5
42'3 2967 2800 ll4ri 1Xi8 1251 ,587 1120 GI0 '378 2921 2899
1111 833.i 485 (m1Y
12.53 1122
1020
740d 233c
144G
1*'%18 1286 1285 104; 1081 1086 874 874 283
1136 879 or 889
CII stretching U30
Ileformation 1461 v32 Twisting 1396 121rJ ua3 Itragging v , ) ~ Rocking 946 King stretching 1 109 1109 yS6 King bending 486 433 * Reference ( 2 ) . e Calculated in refa Reference (3). erence (2) from a normal coordinate treatment of the skeleton. d Observed as weak band and matched with the calculated value of 742 cin-'. T h e observed hand is very strong, however, and is :it 610 cm.-'. u31
( 1 ) Sntionnl Renmrrlt Coiiiicil Post doctorate Fellow. 1 D . i l
433' 486 835 8t50 946 1014 1109 1128 1209' 1222 130:i 1330
Tilt.
422 433 486 834
1 2 4 8
85zh
1
T h i ? research igiiinent C
0 1
8,Z
1013 834 48.;
w m . -1
2
p d p d d p d p d d p p
4 8 1 1 6 3 3 I 5 8 3
940 I018 1109 1127 1216 1303 1334 1396 1443 1461 2662 2720 2748 28,55 2889 2966
VIO VP
uw B,
A, Ag VZI B, V I A, ux V6
I 6 3 3
V ~ LB g
V;
A,
B,
5 8 2 1 8 2
Ag A,
~ 3 3
~ 2
A, 5 UZB A, Y E B, V J A, V ~ IB, -I- ~ 3 A, 3 Vu A, f ~1 A, YP A, 2 ~ 3A, U I A,
+
v4
1448 8 p 1455 2 d 2662 0 p 1 ~3 2720 1 p 1 UT? 2748 3 p 2 VQ 28-54 8 p 8 2890 3 p 2 2966 10 p 10 3064 1 P R, ? a Summary of results of eight authors given by K . u '.F. Kohlrausch in "Ramanspektren. " Polarization measure. ments are by B. Saksena, Proc. Ind. Arad. Sci., 12, 321 (1940). This work. dObtained only by J. Lecomte, J . chitn. phys., 33, 626 (1936). "Obtained by l'enkateswaran, P r o r . Ind. Acad. Sci., 2 , 279 (1835), and Saksena, reference ( b ) . f Observed as double; A. Simon and 1'. Feher, B P I . , 69, 214 (1936). Our Raman spectrum contaiits a band at 1200 cin.-l corresponding t o the band at 1209 c m - l which we are certain is uI excited by X 4047. * This band is assigned as of species A, although it is given 3s depolarized. However, it is not impossible that the depolarization of such a weak hand has been estimated iiicorrectly.
+
-
.~ ___.
( 2 ) D A. Ramsay Proc. R o r . Sor. ( L o n d o n ) ,Al90,562 (1047). I.'{) S C Rrirket and K.M Bzrlger, 'THIS IOURNAI. 74,43'17 (1950)
SPECTRA OF DIOXANE
Sept. 5 , 1932
4409
700 to 3500 cm.-1 and assignments made for the ring frequencies2 and also for some of the hydrogen m q d e ~ . ~The Raman spectrum has been obtained by several investigators and the results summarized by Kohlrausch.4 We had decided to reinvestigate the infrared and Raman spectra of p-dioxane since: (1) the region from 265 -700 ern.-' had not been covered in the infrared, ( 2 ) two low lying lines below 300 cm.-l were reported in the Raman spectrum by some authors and not by others (see Table 11),(3) only one of the eight independent Raman spectra previously obtained reported the band 433 cm.-' to be double (see footnotef to Table 11). The infrared spectra were obtained on a PerkinElmer Spectrometer (Model 12c) with electronic recording and LiF, NaCI, KBr and KRS-5 prisms. The results are shown in Fig. 1 and Table 111. In Fig. 2 the infrared spectrum of solid p-dioxane is shown only in the spectral regions where marked changes from that of the liquid were observed. TABLEI11 INFRARED SPECTRUM OF LIQUID #-DIOXANE win
-1
273 283 610 708 733 750 874 887 1046 1081 1110 1120 1251 1286 1318 1368 1400 1446 1500 1707 1729 1855 1901 1917 1956 1990 2072 2089 2131 2177
Intensity
in in 5
w w
w s s m s
w
Assignment
Bu vs Au YIE B u ug ulg A" u7 - USE A, Y ~ O VI^ A" V27 Au YI6 Bu ~ 2 Au 5 P i 6 A,, us+uzaAu
+ +
Bu Bu
s
VI7
s
VIS
s m
~ 2 3
ni W'
s
Au Au Y14 Bu Y I Bu ~ ~ 2 4
+ + + + + + + + + ug + + + + Y;
VI31 V 2 2
U'
VI
AU ~ 2 Au 7 Y3l A, YIO Bu Y16 Bu
w
UP
YIE
US
817
\V
V26
W
YE
1%'
Y I ~
W
Y I ~
\v
w w
~ 3 j
w
v7
w
ug
w
u4
VIO
Bu
Bu Au Y ~ Bu S V20 Au U24 Au V Z Au ~ VI6
ucm
-1
2193 2212 2225 2260 2273 2283 2340 2391 2470 2582 2695 2760 2860 2899 2921 2967 3133 3250 3299 3336 3407 3479 3534 3610 3910 4143 4340 4410 4470 4850
Fig. 1,-The infrared spectrum of liquid p-dioxane: 0.10 nim. cell; ----,pressed plates; the bands at -280 cm.-l were obtained in a 1.5-mm. cell.
-,
Intensity
w N'
\v
w w w w w
w
w w w s w w s
w w 850
w w
900,1000
1100 FREWENCY
I
1250
1300
CM?.
Fig. 2.
w w
w w \v
w
w w w
The Raman spectrum was obtained with a twoprism glass spectrograph (camera f/7.7, linear dispersion 11 8./mm. a t X 4358) on an Eastman Kodak 103a-J plate after 9 and 30 hours exposure. Three thicknesses of Wratten 2B gelatin filter and a solution of praseodymium nitrate were used to reduce A4047 excitation and mercury continuum near the (4) K W F Kohlrdusch "Ramanspektren," Arlii Arbor, Michiy.iii, 1943, p J4.2.
,
LlQUlD
w
Edwards Bros
exciting line. Two Lane-Wells type Hg arcs run a t 25 amperes were used as sources. The results are shown in Table I1 along with the summary of the previous work done. In the Raman spectrum we have not found anything below 300 cm.-' even on long exposures whereas the two lines a t 422 and 433 cm.-' were very readily resolved. There can be no doubt that the three low lying fundamentals which are to be expected in the Raman spectrum are a t 422, 433 and 486 cm.-l. I n the infrared spectrum a very strong band has been observed a t 610 cm.-' and two others a t 273 and 283 cm.-l. Thus the complete spectrum due to the skeletal vibrations has been observed. The assignment for p-dioxane is made on the basis of the point group C 2 h since it seems well established that in p-dioxane those molecules with the
boat configuration (C2") are present in an almost negligible amount.6dp6b The thirty-six modes of vibration are divided among the four symmetry types in the following manner: 10 A, (Raman active, Infrared inactive), 9 B, (Ranian inactive, Infrared active), 9 A, (Ranian inactive, Infrared :ictive), and 8 B, (Raman active, infrared inactive),6 A g Vibrations.-From the intensity in the Kainan spectrum and state of depolarization it seems probable that the skeletal modes vIo, v9, vs and Y; are 422, 433, 834 and 1013 cin. -I, respectively. By comparison with the assignment of the modes in cyclohexane'one may expect to find the hydrogen bending frequencies separated roughly into the following spectral regions : (a) deformation vibrations giving rise to bands around 1450 cm.-l; (b) twisting vibrations giving rise to bands around 1800-1390 ciii. - I ; (c) wagging vibrations giving rise to bands around 1130-1 270 c ~ r i . - ~and ; (d) rocking vibrations giving rise to bands around 800-1030 cm.Xccordingly, i t seems probable that the strong polarized lines a t 1443, 1303 and 1127 cm.-' are the hydrogen deformation, twisting and wagging modes, respectively. The two strong polarized lines a t 5966 and 2855 are presumably the CH stretching vibrations vl and V Z . The assignment of the rocking vibration vi, 15 made in conjunction with the identification of the B, type rocking vibration and thought to be 8 . 2 cin.-l. The magnitude of this frequency is about right but the band is given as depolarized (see Table 11;. It is not improbable, however, that the de5 ) (a) See reference ( 1 ) for d 3ummar) of t h e supporting dipolt moment and electron diffraction result5 b) liecentii 13 Gibbi 7,iiizs F W U ~ USuiY D z r i ) t o 1931 p 122) i t has been suggested t h n t a small a m o u n t of t h e dntrsj mmetricil czs form of point group ( 2 7 ma) present 6) C, Herzberg Infrared a n d Raxnan i p e c t r a , " D Vnn 'ioitrdnd
polarization of such a weak band has been estimated incorrectly. Bg Vibrations.-No depolarized bands have been reported in the CH stretching region of the Raman spectrum. The four strong depolarized Raman lines a t 1461, 1216, 1109 and 486 are presumably the hydrogen deformation and wagging vibrations, and the stretching and bending of the ring, respectively. The line a t 1396 c m - l might very well be the twisting vibration whereas the line a t 940 cm.-l is probably due to the rocking vibration. I t is possible that v34 and v6 may be interchanged; however, antisymmetrical frequencies are usually higher than totally symmetrical ones. I n order to keep the Raman active rocking frequencies V 6 and v34 in the same spectral region, the fairly weak polarized line a t 1334 crn.-' in the Raman spectrum is interpreted as a combination tone of the lines a t 1036 and 2S3 c i i ~ . - ~ . A, and B, Vibrations.--The intensities of the inirared bands make a reasonable selection of fundamentals possible since all weak bands can be explained by a t least one binary combination (see Table 111). There are no compelling reasons why most of these bands belonging to corresponding vibrations cannot be interchanged. The assignment 'is given (see Table I) is consistent with the data but must be regarded as tentative. I t is believed however that all fundamentals of thermodynamic significance have been observed. The specific heat (C;) of the gas a t 300, 350 and 400°K. has been calculated by the well known methods of statistical thermodynamicss and found to be 22,,X, 2(i..i8 and :I K I A r
69 IS
>rr r t i c r r n r c
131
11
-101 r l
rl
