LITERATURE CITED
Table 111.
Partial Mass Spectra
Cg o-Methylaminobenzoates mle
22 1 206 192 178 151 134 133 132 116 105 104 77 73
Composition
M+ (M-CHI.) (M-CzHs.)+ (M-CaH?.)’ (M-CsHio)+ (M-CrHn+O*) (151-H20)+
n-Pentyl
2-Methyl1-Butyl
18.2 0.14 0.02 0.22 16.8 8.63 10.2 5.64 0.95 18.5 5.64 6.17 1.68
16.2 0.03
20.3 0.09 0.04
+
0.08
+
(133-H. )
(134-HzO!f (133-CO) (105-H.)+ (105-C2)+ (C4HsO)
13.7 7.59 10.6 6.10 0.93 19.0 5.99 7.51 1.52
hydrogen involvement is required to explain the shift from 116 to 118 in the CD, compound and no shift when DzO was introduced into the ion source simultaneously with the CH3 compound. I n the latter case, partial deuteration resulted in the 134 fragment being split into 134 and 135; b u t no corresponding change took place in the 116 fragment. A parallel fragmentation of the 134 ion leads to a second 105 species and, subsequently, the 77. The trideuteromethyl compound
134 -
(137)
ANALYTICAL CHEMISTRY
3-Pentyl 11.4 0.03 0.02 0.02 29.8 8.96 9.31 2.99 0.91 19.5 5.06 5.69 0.42
0.08
0.02 25.3 7.42 9.51 3.84 0.88 20.6 5.14 5.80 0.09
RECEIVED for review June 8, 1966. Acce ted August 23, 1966. Presented a t t i e meeting of ASTM Committee E-14 on Mass Spectrometry, St. Louis, Mo., May 16-21, 1965.
The principal fragment from N, Ndi-n-butyl o-methylaminobenzamide is the benzoyl ion at m/e 134 which behaves as it 0
-
“-@m* -NGH,),
a&,H, 262 CH,
17s)
P ” 134 CHI
before
115)
IiSil
did when formed from the butyl ester. The second largest peak in the spectrum is a t m/e 128. Exact mass measurement showed it to be CBHIBN.The mos,t
-
105 -
77 (78)
[ 106)
yielded peaks at 106 and 78 which high resolution mass measurements showed to be C7H4D0and C6H4D,respectively. The spectra of four pentanol esters were examined to establish the effect of structure. Each was prepared from the alcohol and purified by gas-liquid chromatouaohv, I n Table I11 are given th; ie(ghts (relative to total ionization above m/e 24) of the larger peaks plus several which might be expected to show structure-dependent changes. Those fragments resulting from loss of alkyl radicals from the parent ion (206, 192, and 178) are too small for their differences to be significant. The variations in relative heights of the 221 and 151 peaks are consistent with what might be expected on the basis of the “branchiness” of the neutral olefins produced but are neither specific nor dramatic enough to be useful for structure determination of esters prepared from unknown alcohols.
1740
3-Methyl1-butyl
straightforward process for its formation is simply cleavage of the carbonylnitrogen bond b u t this is not the 0 a C ? - NHN‘ C , HC”,,
262 CH,
‘53)
-
0 N %4 H,
1161
128 1128%
(1)- Biemann, K., “Mass Spectrometry, Organic Chemical Applications,” p. 1766, McGraw-Hill, New York, 1962. (2) Crable, G. F., Kearns, G. L., Norris,‘ M. S., ANAL.CHEM.32,’ 13 (1960). (3) Lanaer, S. H., Friedel. R. A,. Wender. I., S h k e A. G., ’ Jr., Ibid., 30, 1353 (19583r.) (4) Sharkey, ’A. G Jr., Friedel, R. A,, Langer, S. H., Idid., 29, 770 (1957). (5) Staiger, R. P., Miller, E. B., Jr., J . Org. Chem. 24, 1214 (1959). (6) Staiger, R. P., Moyer, C. L., Pitcher, G. R., J . Chem. Eng. Datu 8 , 454 (1963).
1291
only process operating. Both Tu’-D and N-CDs compounds have both 128 and 129 peaks which indicate t h a t there must be a parallel reaction involving transfers of hydrogen from and t o the dialkylamine portion of the molecule. ACKNOWLEDGMENT
The author thanks the Maumee Chemical Co. for a sample of N-methylisatoic anhydride and for the literature on its chemistry. The experimental assistance of J. B. Murdoch and T. W. Hansen is appreciated.
Corrections Characterization of Flame Photometric Detector for Gas Chromatography I n this article by Richard S. Juvet, Jr., and Ronald P. Durbin [ANAL. CHEM.38, 565 (1966)l a typographical error appeared on page 565, column 3, line 40. The sentence should read as follows: “An oxy-hydrogen flame was used at an oxygen flow rate of 3.1 liters/ minute and a hydrogen flow rate of 5.7 liters/minute (S.T.P.).”
Deter minat ion of S ma I I Amounts of Oxygen Using a Hersch Cell as a Gas Chromatography Detector I n this article by G. E. Hillman and John Lightwood [ANALCHEM.38, 1430 (1966)], on page 1433 the Note in column 2 states that “the Hersch Cell” is the property of Engelhard Industries, Inc. T o avoid any misunderstanding: the Company named does hold U. S. Patent 2,805,191 (misprinted as 2,805,701) b u t i t does not hold any of a series of other cells also originated by Hersch. Some of these, like the galvanic-coulometric cell of U. S. Patent 3,223,597 also relate to oxygen, others to a number of different gases; the British Patent 880,965 relates specifically to gas chromatography. I n a bulletin describing their “Minoxo Indicator,” Engelhard specifies U. S. Patent 2,805,191but does not refer to this instrument as the, or a, Hersch cell.
P. A. HERSCH
