COMMUNICATIONS TO THE EDITOR
190
CILOO. + R H +CHzOOH + R * (6) RH might be aaomethane although it might also
be formaldehyde, since the experiments were carried to a high conversion a t constant azomethane concentration. (ii) Experiment 7 was done under conditions similar to those reported by Hanst and Calvert,' except, for lower intensity. While they did not find methyl hydroperoxide among their reaction products, under our conditions, this substance was readily detected. (iii) Abetraction of a deuterium atom from CD4 by CI130z., even at temperatures as high as 158' is not rapid. The results of Gray6 and Nalbandyan" on methane, might then be reinterpreted in terms of the mechanism suggested by Watson and DarwentlZ for ethane oxidation. A preliminary estimate of the quantum yield of the hydroperoxide (iodometric titration), indicated (11) A. B. Nalbandyan, Zhur. F?z.Khzm., 32, 1443 (1948). (12) J. S. Wrttson and B. deB. Darnent, THIBJOURNAL, 61, 577
(1957).
Vol. 65
TABLE I CONSTANT PRESSURE OF AZOMETHANE = 6.6 MM. PRESSURE OF OXYQEN(AT ROOMTEMPERATURE) = 11 MM.
Expt. no.
1 2 3 4 5 6 7
Other gases present in em.
COz; 48 Cot; 48 COz; 48 CDI; 48 CDI; 48 Propylene; 12 Oxygen; 70
Teyp.,
C.
27 105 158 27 158 27 27
CHsOOH mle 48
Present Present Present Present Present Present Present
CHsOOD, m/e 49 CDsOOH. m / e 51 CDsOOD, m/e 52
Absent A4bsent
that it lay between 0.5 and unity for conditions as in experiments 4 and 5, but wit,h CHI and at 100'. Thus it was an important product of the reaction. More quantitative work on the formation of methyl hydroperoxide is now in progress. The authors wish to acknowledge the generous assistance of Dr. F. P. Lossing and his associates for the mass spectrometric analyses.
COMMUNICATIONS TO THE EDITOR GAS
CHROMATOGRAPHY OF PARAHYDROGEN, ORTHOHYDROGEN, HYDROGEN DEUTERIDE AND DEUTERIUM
worthwhile to separate ortho-Hz and HD or to obtain four separate peaks, para-Hz, ortho-Hz, HD and Dz, on a single chromatogram. I n this communication we wish to present such a method and analytical data found with it. The separation of this kind would be realized if Sir : The gas chromatographic separation of hydrogen one employs two sorts of columns in series; the isotopes HI) and Dzl and nuclear spin isomers para- first contains alumina or Molecular Sieves and the Hz and ortho-H22 on suitable adsorbents kept a t second paramagnetic substances in addition. Para-195" was demonstrated in 1958. Since then it Hz, eluted out of the first column, would undergo has become of interest to suppress the separation of rapid para-ortho conversion during passage through para-ortho isomers and hence to give three peaks the second column presenting a peak. Ortho-Hz, corresponding to HS, HD, Dz on absingle chromato- with a certain time delay, will follow a similar begram. Smjt h and Hunta used chromia-alumina havior. Now, if the second column be efficient columns and Moore and Ward4used alumina pack- enough also for the separation of three isotopic ings coated with ferric oxide, both making rapid forms, ortho-Hz and H D ought to be separated on para-ortho interconversion and thereby giving a this column. Consequently, we may expect the unified peak for these isomers. I n the absence of four peaks mentioned above. Experiments were made with the apparatus and such pararnagnetic substances on the columns, ortho-Hz and H D overlap and the three apparent procedure reported previously.6 An actire alumina peaks are para-HZ, ortho-Hz plus H D and DO, column 200 X 0.4 em. was employed as the first respectively, as already reported by Van Hook and column. The second one was filled with active alumina coated with ferric oxide after Moore and Emmett5 and by I
