Infrared Spectra of 1,2-Epoxybutane SIR: The spectra of a number of various compounds containing the oxirane ring have been published ( 1 , 2, 5; 6), but no spectrum of 1,2-epoxybutane appears to have been recorded. This spectrum was needed for identification of 1,2-epoxybutane in a mixture of the four epoxybutanes. A sample of this compound was synthesized here and its spectrum recorded on a Grubb Parsons prism spectrometer (S4) using an undiluted sample and cells of 50 microns and capillarjpath length. This spectrum has two strong bands a t 11.1 and 12.0 microns (Figure 1). Shreve et al. (6) found that the oxirane ring in the terminal position is responsible for bands near 11 and 12 microns, but in the spectrum of 3,4-epoxy-l-butene a shift to 12.23 microns is found. This may be due to the effect of the adjacent double bond on the vibration involved. The presence of a band a t 12.0 microns in the saturated compound, 1,2-epoxybutane, supports this suggestion. A band of medium intensity a t 12.53 microns in the spectrum of 1,2-epoxybutane can be confused ivith that of a major band in the spectrum of 2-methyl1,2-epoxybutane (12.56 microns), when identification of components of mixtures of isomers is attempted. This sample of 1,2-epoxybutane was prepared from monochloroacetal, which was converted to 1-chloro-2-hydroxy-
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Figure 1.
Infrared spectrum of 1,2-epoxybutane
butane by the method of Helfenich and SPeidel ( 3 ) . The chlorohydrin mas dehydrochlorinated by the procedure of Montmolin and hfalili (4) to yield the required Oxirane' This material was purified by distillation from sodium. Although the sample contained a little water, examination by gas-liquid chromatography showed only one Peak, indicating the absence of other isomers. ACKNOWLEDGMENT
The author thanks M. A. Birch and E. C. Campbell for assistance and the directors of "Shell" Research, Ltd., for permission to publish this note.
LITERATURE CITED
(1) Bomstein, J., A N ~ LCHEM. . 30, 544 (1958). (2) Field, J. E., Cole, J. 0.7 Woodford, D. E., J . Chem. Phys. 18,1298 (1950). (3) Helfenich, B , Speidel, J. A., Ber. 54, 2634 (1921). (4) Montmolin, &I.,RIalili, P., Helv. Chzm. Acta 7, 106 (1924). (5) Patterson, A,, ANAL. CHEbr* 26, 824 (1954). (6) +-eve, 0 D., Heether, RI. R., Knight, H. B., Swern, Daniel, Zbzd., 23, 277 (1951).
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R. A. G. CARRINGTON Thornton Research Centre Shell Research, Ltd. P. 0. Box 1 Chester, England
Separation of Micromole Mixtures of 2,4-Dinitrophenylhydrazones SIR:The 2,4-dinitrophenylhydrazones are widely used as derivatives for the determination of carbonyl compounds, and a number of procedures have been proposed for the separation of individual derivatives from a mixture. A few of these are applicable to micromole amounts; those involving paper chromatography have an appealing simplicity, but frequently give variable results. Khile column procedures are generally more reproducible, the adsorbents mag require involved activation treatments, and exhibit variations in behavior from hatch to batch. Some of the more rcliable procedures are extremely slow, requiring long periods to effect separations. To the chemist interested in flavor analysis, one of the more rewarding approaches has been that suggested 11.- bIonty ( 2 ) , using Hyflo Super-Cel activated rvith nitroinethane as a stationary phase, and petroleum ether saturated with nitromethane as the developing solvent. The work reported here was directed
to extending the data to include a number of carbonyls encountered in flavor analysis, and modifying the technique to permit shelf storage of the adsorbent and speed column preparation. Because most naturally occurring flavor carbonyls are obtainable only in very small amounts, elution techniques such as that reported by Monty are not always satisfactory for their study. Single components that exhibit tight, discrete zones early in a separation frequently become diffuse and less distinct further down the column. Therefore, developing rates are reported herein as relative rates of progress through the column. DINITROPHENYLHYDRAZONES
2,4-Dinitrophenylhydrazones \\-ere prepared from technical grade carbonyl compounds (escept as mentioned belon) by the method of Shriner, Fuson, and Curtin (4); perchloric acid was substituted for sulfuric acid. A few carbonyls (n-propanol, n-pentanal, 2-butanone, "hexPreparation.
anone, 2-octanone) were prepared from the corresponding alcohols by distillation over sulfuric acid-potassium dichromate. hfethional was synthesized by the method of Pierson, Giella, and Tishler (3). All dinitrophenylhydrazones except biacetyl were recrystallized a t least twice from ethyl alcohol or ethyl alcohol-water. Melting points were checked ( 1 , 3 , 4 )and the chromatographic homogeneity of each sample was established. Chromatographic Columns. Hyflo Super-Cel (Johns-Manville, S e n York, S . Y.) mas thoroughly mixed I\ ith an equal weight of nitromethane (technical grade), and the mixture was stored in a screw-cap bottle. Chromatographic columns (9 X 250 mm.) were packed with 10.0 grams of this mixture. There n-ere indications that columns packed ivith a slurry exhibited greater uniformity from column to column, but that the rate of a derivative through the column increased with the distance traveled. This was attributed to greater compaction a t the top of the column. To overcome this, the support was added in VOL. 31, NO. 6, JUNE 1959
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