MOLECULAR REFRACTIVITY AND STRUCTURE OF ORGANIC PEROXIDES
Aug., 1 9 4
yielded mixtures of oxygen compounds containing alcohols, aldehydes, ketones and acids. l4 Assuming that the formation of hydrocarbons froni ketene proceeded step-wise in the following nianner [a,) C H 2 C 0 -+-
c
CT?; .L. C.[;?C() +CT!,CH-.=.C-()
(1))
(:-)
+
CE1:qC;I- C=-:--O+CH,-CHZ CO C j J , + CJijCH=C::--.C)+ CILCI-.OOH(CI.)~
"CII3 00" I
Ether analogs
Dialkyl peroxides
0 - 0 0 C H 3 (inact .)
.... ....
... ...
13.08 17.70 22.32 40.78 50.02 68.49 54.51
.49
...
52.42
35.69
.20
...
33.50
.... ....
54.74
54.16
.58
...
51.97
..
47.35
46.41
*
94
...
44.22
....
15.40 20.09 24.74 43.36 52.53 68.80 56.80
15.27 19.89 24.51 12.97 52.21 70.68 56.90
0.13 .20 .23 * 39 .32 -1.88 -0.10
55.10
54.61
i35.95
. .. 22.470 40.68"
...
0.15 .10
.... ....
....
MOLECULAR REFRACTIVITY AND STRUCTURE OF ORGANIC PEROXIDES
Aug., 1946
1619
TABLE I (Concluded) Peroxide
MRD
YDialkyl peroxide
MRD
(obs.)
(calcd.)
51.83
51.05
Exaltation
OOCHa' I .80
(calcd.)
Exaltation
...
48.81
..
Hydroxyalkylperoxides
HOCH200CH3C CH3CH(0H)OOCHa' C2H500CHz0HC CzHjOOCH(0H)CHaC
16.95 21.35 21.56 25.17
16.79 21.41 21.41 26.03
L-C,iHgOOCO-
on
MRD
Hemiacetal analogs
0.16 - .06 .14
-
11 60 19 22 19 22 23.84
... ...
.86
...
Ester analogs
Peresters
t-CaHgOOCOCsH5" ~-C~H~~OOCOC~HS''
Water
MRD (obs.)
54.84 59.16
53.24 57.86
1.60 1.30
51.860
...
51.05 55.67
...,
47.46
46.11
1.35
...
43.92
....
0.81
t-C4HgOOCOCH=CHCH," 43.85 42.52 1.33 ... 40.33 .._. t-C,HsOOCO [CHz]sCH=CHz" 75.72 74.85 0.87 ... 72.66 .... Ref. 3 . * R'ef. 5 . Lange, "Handbook of Chemistry," Sandusky, Ohio, 1937, pp. 734-837. Medwedewa and Ateuejena, Ber., 65B, 133 (1932). e Milas and Surgenor, THIS JOURNAL, 68, 205 (1946). f Milas and Surgenor, ibid., Hock and Lang, Ber., 76B, 169 (1943). Hock and Lang, 68, 613 (1946:'. Milas and Perry, ibid., 68, Sept. (1946). ihid., 77B, 257 (1944). i Criegee, Pilz and Flygare, ibid., 72, 1799 (1939). k Hock and Lang, ibid., 75B, 300 (1942). Erickson and Ashton, THIS Hock and Lang;, i h i d . , 75B, 1051 (1942). JOURNAL,, 60, 2434 (1938). Milas and SurNorris and Rigby, ibzd.,54,2098 (1932). P Ref. 4. genor, ibid.,68,ti12 (1946). Q
error or to lack of absolute purity. Real exaltations, however, appear in hydroperoxides, dialkyl peroxides and peresters which contain the aromatic nucleus or carbon-carbon double bonds usually attached to the molecule in positions beta to the peroxidic oxygen. In these cases the peroxide group seems to behave like an unsaturated group in conjugation with the carbon-carbon double bond. The peresters show an exaltation almost equivalent to an additional oxygen atom. Since the normal esters also show small but real exaltations, the increased exaltation in the peresters must be attributed to the peroxide group. To account for ithe high exaltation shown by the peresters, structure I11 of the perester group is postulated in which the two oxygen atoms attached to the same carbon atom are equivalent, as in the case of the carboxylic acids, and the oxygen attached to the tertiary carbon atom is hound to the two oxygen atoms by single electron bonds. Such a hybrid structure should be in
,_
I11
resonance with the normal structure IV. If the peresters have structure 111, they would be expected to show abnormal properties. This has actually been found to be the case with all of the t-alkyl peresters so far synthesized! Acknowledgment.-The authors wish t o thank the Union Bay State Chemical Company for financial support in carrying out this investigation. Summary 1. A simple method for the calculation of the molecular refraction of organic liquid peroxides has been proposed. This method is based on the addition of 2.19, the atomic refractivity of the peroxidic oxygen, to the calculated molecular refractivity of the normal oxygen analog of a given peroxide. 2 . The molecular refractivities of 13 alkyl hydroperoxides, 12 dialkyl peroxides, 4 hydroxyalkyl peroxides and 5 peresters have been calculated and the values obtained compared with the observed values. 3 . A hybrid structure of the peresters has been postulated to account for their abnormal exaltations. CAMBRIDGE 39, MASS.
RECEIVED MAY1, 1946
