ANALYTICAL CHEMISTRY
1030 readily apparent, in every case of a compound not having the alpha atom substituted there is a strong band a t -13.4 microns, never below 13.3 microns. On the other hand, the great majority of the compounds having an alpha hydrogen substituted have a strong band at -13.2 microns, never above 13.3 microns. If the alpha and beta atoms are both substituted, the band 2 just as in the case of alpha substitution occurs at ~ 1 3 . microns, only. If the alpha atom is doubly substituted, the situation i* .till like a single alpha substitution, except the band may be a t slightly shorter wave length (compare tert-butylbenzene and isopropylbenzene). The two substituents (of those examined) which frequentlv violate the above rules are phenyl and chlorine. Phenyl substitution would be expected to behave differently: I n the molecule 1,l-diphenylethane (see Table I ) one is dealing with identical oscillators very closely coupled, and the resonance splitting Qhouldbe pronounced. Such multiplicity of absorption bands is still apparent in 2,3-diphenylbutane, but is absent in his(aphenyl ethyl) ether, a single band being found at 13.18 microns. A possible explanation of the irregularities with chlorine wh-
stitut,ion might be that of accidental degeneracy (Fermi resonance). The carbon-chlorine stretch frequency lies in this same region of the spectrum, and its interaction with the vibrations under discussion could conceivablj- account for the observed irregularities, iyhich are not observed with any other electronegative substituents studied. .It present, there seems to be no good way to account for the general regularity of the wave length of this band with position of side-chain substitution. This regularity is pointed out here merely as a useful tool in the characterization of structure of sidechain-substituted monoalkyl benzeilrs. LITERATURE CITED (1) Colthup. X. E., J . Opt. Sot. A m c i . , 40, 397 (1950). (2) XIcAIurry, H. L., and Thornton, V.,d s a ~CHEM., . 2 4 , 3 1 8 (1952). J . Chem. Soc., 1947, p. (3) Richards, R . E,. and Thompson, H. W.,
1260.
(4) Whiffen, D. H., and Thompson. H. W., I b i d . , 1945, p. 268. ( 5 ) Young. c. w.. DuVall, R. R., and Wright. s., dN.4L. CHEhl., 23, 709 (1951).
RECEIVED for reviriv October 4, 1Y.54. .Accepted December 28. 1954.
Anomalous Behavior of Certain Tetraalkyl bibenzyls in Zeisel Methoxy Determination R. L. HUANG
and
LEE KUM-TATT
Department of Chemistry, University o f Malaya, Singapore ~~
The derivatives of tetramethylbibenzyls were determined for methoxy groups by modification of the Zeisel method.
Tahle I.
Inal>ses of Derilatites of Tetramethylbibenzjls
D
U R I S G the synthesis of certain substances related to hesestrol, derivatives of tetramethylbibenzyls (I, R = R' = Me; X = H, SOZ, or OH), although devoid of methouy groups, were found to give small but definite apparent methoxy value. when analyzed for such groups ( 2 ) . The authors present the analytical technique employed. and report that similar anomalies have been encountered in the same type of bibenzyl(1) in nhich the substituents R and R' are alkyl groups other than methjl [substances (11) to (VI), Table I]. However, the structurally related succinonitriles(VI1) and (1'111) do not exhibit this ahnormal behavior under the same conditions of analysis. Except for (5') and (LT), all the reported substances \\ere prepared by free-radical dimerization using di-tert-butyl peroside Compounds (V) and (VI) ere synthesized by a totally different method involving reduction a i t h zinc and hydrogen iodide ( I ) .
R R -ya-(.--c.-x-+-Ay -
R' R' H; R = hle, R' = E t (meso and racwiiic.~ NO*; R' = Et (meso and racemic) OH; R' = E t (meso and racemic) OH; R = R' = Et PhCOO; R = R ' = n-Pr R R
--
~
Melting Point, C .
Methoxy Found, '"0
93 40-1
2 ti 2 2
201-2
3 3 3 li
152 17R
Racemic 3 , 4 - D i - p - h y d r o x ~ p l i e n y l - 3 , 4 - d i e t l i ~ l l i e ~ V) ne~ 4,5-Di-p-benzoyloxyplienyl4,j-di-n-grolJyloctane ( V I ) '7.3-Diphenyl-2.3-dicyanobutane(VII) Neso 3.4-Diphen3.1-3,4-dicyanohezanhe~ane ( V I 11) Meso Race iii i c
1 8 ~.
103-4
is6
'73 2 0
182-3
2.4
224
0
174-5 117-18
0 0
EXPERlAl EYT 4L
The determinations of methosy (3) were carried out, under more vigorous conditions than those normally applied in the estimation after Zeisel. The technique was that normall:; employed for the estimation of S-methyl in an apparatus similar to that of Pregl, except t,hat ammonium iodide was not added. The specimen dissolved in phenol and acetic anhydride waF boiled in hydriodic acid and evaporated t o dryness, and t,he residue heated to above 300' C. In this manner, quantitative results could be obtained in the case of a number of phenolic methosyls, but discrimination between N-methyl and O-met,hj-I rannot be achieved thereby. .4CKNOWLEDGMENT
The authors thank the Shell Co. of Singapore, Ltd., for a research fellowship (to L.K.T.), and G. Keiler and S. B. Strauss for carrying out the analyPe9. LITERATURE CITED
CN ch
R R
= Me (meso) =
E t (meso and racemic)
Huang, R. L., and Kum-Tatt. Lee, J . Chem. SOC..1954, p. 2570. Huang, R. L.. and RIorsingh, F.. ANAL.CHEM., 24, 1359 (1952). (3) Weiler, G., and Strauss, S. B.. Oxford, England, private communication.
(I) (2)
RECEIVED for review April 20. 1954. .Accepted January 12, 1955.
