V O L U M E 26, NO. 5, M A Y 1 9 5 4 The precision of the chromatographic separation alone was investigated by performing duplicate analyses on aliquots of impure solutions of codeine salts. The results of these analyses are shown in Table IV. Purity of the Codeine. I n the analysis of relatively pure .amples the codeine eluted from the column is colorless and cqrstalline, but with very impure mixtures such as opium, the (,luted codeine will vary from nearly colorless to light brown. Figure 5 is a graph of the weights of a series of frartions obtained in the analysis of a sample of opium plotted as a function of fraction number. After being weighed the eluted alkaloid fractions were dissolved in 95% ethyl alcohol and the absorbances of the resulting solutions were measured at wave lengths of 275 and 290 mp using a Beckman Model DU spectrophotometer. The iatio of the absorbance a t 275 to that a t 290 mp was computed for each fraction and these ratios are also plotted in Figure 5 The same ratio was determined for pure codeine, thebaine, neopine, and papaverine and theee values are shown in Table T'.
823 The melting point of the codeine in 1r:iction 23 waq 153 :3 to 154.5' C.. that of fraction 26 was 153.3' t u 154.5' C., and that of traction 27 was 149.4' to 151.0' C. The melting point of a .ample of codeine of Sational Formulary IX quality was 155.4' to 156.2' C. These data further confirm the purity and identity of t h e material eluted from the column. ACKNOWLEDGMENT
The authors wish to acknoirledge the contribution to this ~ o r k made by members of the Organic Research Department :ind Department of Chemical Control of the Mallinckrodt Chemical Korks who assisted in some of the experimental work dewrihcd :md n ho offered many helpful suggestions. LITERATURE CITED
Raizer, AI. 31.,Loter, A , , Ellner, K. S.,and Satriana, D. R.. J . Org. Chem., 16, 543 (1951).
Girard, P., Ann. pharm. f T a n G . . 8, 572~-3(1950). Homeyer, A. H., aiid Shilling, T V . I>...J. Org. Chem., 12, 356
Table V. Absorbance Ratios for Pure Allcaloids Alkaloid Codeine Thebaine Seopine Papaverine
(1947).
Nee. F. C., and Kirch, E. R., J . A w Pharm. Assoc., Sci. 42, 146 (1953).
Absorbance, 275/290 mp 0 897 i- 0 005 0 859 i- 0 005 1 29 i- 0 06 1 34 i- 0 05
El/.,
Kondo, H., J . Pharm. Soc. Japau. 57, 2118 (1937).
Levi, J. R..and Castelli, F., Arg7/ir. b i d . (Sao Paulo), 23, 2G3 (1939).
Levi, J. R., a,"d Cast$, F,.G a m . r h t r r t . ital., 68, 459 (1938). Sapara, V., Casopis CeskBho L 6 k d r u i c t i v . 63, 293-i (1950). Ptolman, A, and Stewart, C'. P., A ~ l a i y s t 74, , 536-42 (194ij. Stolman, A , , and Stewart. C . P.. I h i d . , 74, 543-6 (1947).
The ratios for the fractions in the codeine peak ale very close to that of codeine, and different from those of the probable impurities, indicating that the material is substantiallj- pure rodeine
Infrared Absorption Bands Characteristic of the Oxirane Ring W. A. PATTERSON' Central Research Laboratory, Canadian Industries, Ltd., McMasterville, Quebec, Canada
Part of the research program of this laborator) required the slntheses of a number of epoxy compounds. I n a follow-up of this program there was need for suitable methods for detecting these different compounds. Infrared spectroscopj appeared to offer the best hopes of success. This invol\ed a study of the infrared absorption spectra of the compounds. The infrared absorption of 26 epoxl compounds were recorded from 2 to 15 microns, in the liquid state and i n solution. The presence of a characteristic absorption band a t about 8 microns was confirmed and evidence compiled for two other characteristic absorption bands a t about 11 and 12 microns. The position of the latter bands \aried with the rompound, ranging from 10.52 (950 cm.-I) to 11.58 microns (863 cm.-l) in the 11.0-micron position and from 11.57 (864 cm.-l) to 12.72 microns (786 c m - l ) in t h e 12-micron position. Some correlation between the wa%e-lengthposition of t h e bands and the reartilit? of t h e compounds with acetic acid was noted. This rrork adds to t h e linowledge of the infrared ahsorption spectra of cpoxj compounds. I t also estahlishes the existence of characteristic infrared absorption bands for the epoxide ring i n t h e 10- to 13micron region. JIeretofore, e\idence of this had been limited. The correlation between t h e wave-length positions of the bands and t h e reacti\ities with acetic acid is of considerahle theoretical interest and of possible practical use.
.
A
S POIKTED out by Shreve, Heether, Knight, and Sn.ci,n
(8),little has been reported on the infrared spectra of heterocyclic oxygen compounds. They added materially, howwer, to the published data by reporting on the infrared absorption spectra of 13 oxirane compounds plus tetrahydropyran, tetrahydrofuran, and dioxane. Previous to this, Barnes, Gore, Liddel, :tnd Williams ( 2 ) had given a f e n spectra covering a limited range, and Field, Cole, and Woodford (3)had report)ed data on eight oxirane compounds. The lack of spectral data is reflected in the fact that little is known about absorption bands which are characteristic of thtx epoxide ring (oxirane group). Herzberg ( 5 ) , using the results of Linnett, has discussed the infrared and Raman spectra of ethylene oxide and found that there are three wave lengths attributable to the oxygen ring-at 7.92, 11.56, and 12.38 microns (1262, 865, and 808 cm.-l). Lespieau and Gredy (6) and Ballaus and Wagner (1) studied the Raman spectra of a number of simple epoxy compounds and found that the Raman shift a t 1262 em.-' (corresponding to infrared absorption at 7.02 microns) xas constant, while the spectra in the TOO- to nOO-cm.-l region (13 to 11 microns) were so compiicated that it was not possible to assign any frequency with certainty. Field, Cole, and Woodford (3) using the infrared apparently found similar conditions, as they concluded that only the %micron (1250-cm.-') band could be identified with reasonable certainty. Robinson in 1948 in thie laboratory recorded the spectral region a t about 8 microns for 19 oxirane compounds and showed that there mas a strong ah1
Present address, Baird Associates, Inc., Cambridge, Mass.
ANALYTICAL CHEMISTRY
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V O L U M E 26, NO. 5, M A Y 1 9 5 4 sorption band which varied in position from 7.82 to 8.04 microns (1279 to 1244 cm.-1), depending on the compound. The variation in band position with the compound is shown in Table I. The presence of a characteristic band a t about this wave length is therefore fairly conclusive. Reference to the 26 spectra given here shows that the band is usually of good intensity and can be readily detected. A possible exception is a-methylstyrene oxide, the spectrum of which is discussed later in the paper.
Table I.
Epoxide Bands at about 8 Microns
I D Z Robinson) Wave Length, Microns 7.82 Phenoxypropylene oxide 7.84 Butene-2-oxide 7.87 Cyclohexadiene dioxide 7.88 Epichlorohydrin 7.90 Propene oxide 7.92 Cyclohexene oxide 7.92 Ethylcyclohexene oxide 7.92 Vinylcyclohexene monoxide 7.93 rl ether Glycidyl-2-tetrahydropyran 7.96 T'inylcyclohexene dioxide 7.95 Glycidyl methacrylate 7.96 Vinyloyclohexane oxide 7.97 Butadiene dioxide 7.97 Styrene oxide 7.97 Butyl glycidy1,etly 7.97 Diallyl ether dioxide 7.97 Methoxy rnethoxy ethyl gly cidxl ether 7.98 Diallyl ether rnonpxide 8.04 Butadiene monoxide Compound
Wave Number, Cm - 1 1279 1276 1271 1269 1266 1263 1263 1263 1261 1258 1258 1256 1266 1255 1255 1255 1255 1253 1244
The first. a,nd only published success in detecting possible characteristic bands in the 11- to 13-micron region is that of Shreve, Heether, Knight, and Swern (8). They showed that oxirane derivat,ives of terminally monounsaturated compounds have two characteristic bands near 11 and 12 microns and that oxirane derivat,ives of cis monounsaturated fatty acids, esters and alcohols have a characteristic band at 11.8 to 12 microns, while those of the trans isomers have a band a t 11.2 to 11.4 microns. They also showed that the spectra are dependent on the physical state of the compounds. The present paper gives the infrared absorption spectra of 26 oxirane compounds from 2 to 15 microns and carries further the investigation of characteristic absorption bands in the 10- to 13-micron region of the spectrum. EXPERIMENTAL
Instrumental. The infrared spectrometer used was a PerkinElmer Model 12C. The gain was set for full scale recorder response with an applied voltage of 1.0 microvolt. The order of d i t widths and speed changes are as follows: Spectral Range, Microns 1.9 to 3.75 3.75to 5.45 5.45 to 7.45 7.45 to 8.9 8 . 9 to 1 1 . 6 11.6 to13.4 13.4 to15.0
Slit Width, Mm. 0.019 0,031 0.058 0.105 0.150 0.250 0.400
Speed 4 4 2 2 2 1 1
The paper speed of the recorder is one half the normal rate, giving a spectral record size one half that which would normally be obtained a t the indicated scanning speeds. This is a routine procedure in this laboratory and provides a more conveniently sized spectrum M
