Infra-red absorption spectra of C24 phenylcycloalkylalkanes

INFRA-RED A B S O R P T I O N S P E C T R A OF PHENYLCYCLOALKYLALKANES *

C24

M. 1). T E T E R I N A a n d A. A . P E T R O V A. V. Topchiev I n s t i t u t e of Petroleum Chemical Synthesis, U.S.S.R. Academy of Sciences; I n s t i t u t e of Geology and the Development of Mineral Resources of the State Committee for the Fuel I n d u s t r y of the State Planning Commission of the U.S.S.R.

(Received 20 November 1962)

THE third group of compounds studied [1, 2] consisted of hydrocarbons of "mixed structure" the molecules of which contained both benzene and naphthene rings, as well as paraffinic chains. Such hydrocarbons are extremely characteristic of high-molecular-weight petroleum fractions. It was of interest to check whether the simple structure of the spectra of "paraffinic-aromatic" and "paraffmie-cyeloparaffinic" compounds existed in this case (i.e. whether additivity of the spectra of the individual structural units was preserved) or whether the spectra underwent more complex changes. Selection of the structures in this series of investigations was made in such a way that those changes in the spectra which are found on replacing alkyl radicals by cycloalkyl and phenyl radicals were thrown into sharp relief. The present work is devoted to a study of the spectra of five C24 compounds.

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34

M . P . TETERINA and A. A. PETROV

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FIG. l. Spectra of hydrocarbons of mixed structure. I n all the diagrams the full curve--represents a layer thickness of 0.1 r a m ; - - - 0 . 0 1 ram;_._ 0"05 m m ; . . . . . 0"25 ram. I - - l - c y c l o h e x y l - l - p h e n y l d o d e c a n e ; I I - - 1 phenyl- 6-cyclohexyl-3-hexylhexane; I I I - - 1 , 5 - d i p h e n y l - 3 - h e x a h y d r o b e n z y l pentane; I V - - 1,5-dicyclohexyl-3-benzylpentane; V-- 1-phenyl-7-eyclohexyl.4-cyclopentylheptane.

Infra-red absorption spectra of C~ phenylcycloalkylalkanes

135

rABLE1. FREQUENCIES OF THE ABSORPTION BANDS OBSERVED IN THE SPECTRA OF HYDROCARBONS OF MIXED STRUCTURE

I

696 v s 720 s

II

III

IV

V

695 s

695 v s

695 v s

697 s

748 v s

750 v s

740 v s

749 s

761 s 777 s h 785 m

785 s h 800 s h 848 s

830 s h 845m

890 s 908 s

888 s 902 s h

960m

961m

803 m 830 s h 845 s 891 s 907 s 922 s h

796 m 825 845 874 887 908 925

sh s sh s s sh

845 s 887 s 903 s h

960 s

943m 960m

978 s h

977 s h

970 s 976 1003 1032 1068

sh sh s s

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1122m 1135 s h 1156m 1182m 1192 s h 1270 s

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1310 s

1305 s h

1353 s

1350 s h

1376 s 1451 v s

1378 s 1457 v s [ n o t r e 1466 v s ] s o l v e d 1497 v s 1543w

1495 v s 1585 s h 1603 s 1745w 1803m 1877m~notre1887 s h ] s o l v e d 1950m

1608 s 1750 w 1801m 1870 w ~ n o t r e 1877 w ] s o l v e d 1950m

Intensity symbols: vs--very w e a k ; s h -- i n f l e c t i o n .

1005 s h 1031 v s 1074 s

1031 s 1075 s ~ n o t r e 1093 s h ] s o l v e d

1032 s 1073 s ll12m

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l160m 1181m

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1265 s

1269m

1311m

not re-

1351 s

1351 s [ n o t r e 1365 s ] s o l v e d

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1452 v s

1455 v s

1455 v s

1497 v s

1496 v s

1588 s h 1608 v s 1745 w 1804m

1587 s h 1607 s 1750 w 1805m

1497 v s 1540 s h 1588 s h 1607 s 1747 w 1808m 1876m

1881w 1957m

1883m 1951m

strong; s--strong;

m--medium;

solved

1955m

w--weak;

vw--vcry

136

M . P . TETERINA and A. A. PETICOV

The synthesis and physicochemical properties of these hydrocarbons have been given elsewhere [3]. Figures 1, I - V illustrates the infra-red spectra obtained under the conditions of our previous investigation [1]. The frequencies of the maxima and intensities of the bands found in the spectra are given in Table 1. The spectrum of each of the hydrocarbons of "mixed" structure was compared with the previously published [1, 2] spectra of hydrocarbons containing the same structural elements in different combinations.

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:FIG. 2. Spectra of: a - - l - c y c l o p e n t y l o c t a d e c a n e ; b-- 1,7-dicyclopentyl-4heptylheptane.

The following comparisons of the spectra were carried out: I. with 7-hexyloctadecane, 7-cyclohexyloctadecane, 1,1-dicyclohexyldodecane, 7-phenyloctadeeane, and 1,1-diphenyldodecane; II. with 1,5-dicyclohexyl-3-heptylpentane, 1-phenyl-7-cyclohexyl-4-cyclopentylhcptane,1,5-dicyclohexyl-3-hexahydro-ben zylpentane, and 1,5-dicyclohexyl-3-benzylpentane; III. with 1,5-diphenyl-3-heptylpentane; IV. with 1,5-dicyclohexyl-3-heptylpentane; V. with 7-cyclohcxyloctadecane, 7-phenyloctadecane, 1,7-dicyclohexyl-4cyclopentylheptane, and 1,7-diphenyl-4-cyclopentylheptane, and also with the spectra of 1-cyclopentyloctadecane and 1,7-dicyclopentyl-4-heptylheptane, which were measured specially (Fig. 2, a, b). This comparison showed that there exists a series of absorption bands which arc common to the spectra of all hydrocarbons containing certain structural units. The frequencies of the absorption bands arc given in Table 2.

1,5-diphenyl-3-heptylpentane,

Infra-red absorption spectra of Cs4 phenylcyeloalkylalkanes

137

As mentioned earlier [1, 2], these bands coincide, in the main, with the characteristic bands for monosubstituted cycloalkane and benzene rings given in the literature. The intensity of these bands increases according to the number of corresponding rings in the molecule, i.e. the principle of additivity of the spectra of the structural units is preserved. The spectra also contain a series of other bands. However, they are considerably less intense than the characteristic bands mentioned. TABLE 2. COMPOSITIONOF THE SPECTRA Monosubstituted ring

Benzene ring

695-700 740* 900-910 970-980 1031 1070-1074 ll20 1155-i160 1180-1182 1495-1497 1585-1588 1603-1608 1743-1746 1803-1805 1870-1880t 1950-1955

Cyclohexane ring

Cyclopentane ring

845-848 885-890 1265-1270 1350-1355

8905 930-948 977§ 1332-1337

Paraffinic chain

720 1305-1310 1375-1380 1450-1460

* I f the benzene ring is attached to a tertiary carbon atom, the band is displaced to 760 cm -1. t Sometimes double. $ This absorption band is found only in the spectra of hydrocarbons not containing rings other t h a n cyclopentane rings. § Weak band; it is absent from the spectra of hydrocarbons containing only cyclopentane rings, consequently its assignment to the cyclopcntane ring is doubtful.

Not all the bands given by Kusakov [4] for the cyclohexane ring (860, 885, 1135, 1152, 1175, 1190, 1224, 1261 em -1) and for the cyelopentane ring (859, 882, 945, 987, 1105, 1150, 1208, 1295 cm -1) are found in the spectra of the alkylcycloalkanes investigated in the present work. It is evident that some of these bands relate only to a cyeloalkane ring connected directly to a benzene ring (it is the spectra of just this type of hydrocarbons that were studied by Kusakov et al. [4]).

138

M . P . TETERINA and A. A. PETROV

SUMMARY The spectra of hydrocarbons consisting of different rings connected with paraffinic chains consist of absorption bands characteristic for each structural unit individually. The intensity of the characteristic bands depends on the number of corresponding structural units.

Translated by B. J. I-IAZZARD REFERENCES

1. M. P. TETERINA and A. A. PETROV, Neftekhimiya 1, No. 3, 309, 1961 2. M. P. TETERINA and A. A. PETROV, Neftekhimiya 3, No. 2, 161, 1963 3. A. A. PETROV, S. R. SERGIYENKO, A. L. TSEDILINA, P. I. SANIN, Ye, A. NIKITSKAYA and N. A. NECHITAILO, Izv. Akad. Nauk SSSR, Otd. khim. nauk, 1848, 1960 4. M. M. KUSAKOV, M. V. SHISHKINA, Ye. S. POKROVSKAYA and Ye. A. PROKOF'EVA, Izv. Akad. N a u k SSSR, ser. fiz. 26, No. 10, 1257, 1962