ANALYTICAL CHEMISTRY
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typical spectrameter chart. As described and piitured, the scales present complete d-value data for successive increments of O S o of two-theta, or of 0.05" of theta. By interpolation it is a simplcmtter toobtain thed-valuesforstillsmallerinerementsof Bragg angle. If desired, similar soales may he constructed for use on spectrometer charts oh%ined by using radiation other than copper Xa,or on charts obtained by using a different speed of Geiger-counter travel.
Identification of Alcohols wil
2,4-Dinitrophenylhydrazine
FREDERICK R. DUKE AND ROBERT C. 1 Ked& Chemical Laboratory, East Lansing, mccn.
T H E procedure described here allows the rapid identification of primary and secondary alcohols,and the presence of water does not interfere. The method depends upon the oxidation of the alcohol to the corresponding carbonyl cornpound, which is identified as the 2,4-dinitrophenylhydraeane.
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Proceduri. To lO.ml. Gf the permanganate'solution is added 0.5 mi. of the dcohol or the equivalent. The mixture is shaken
the 2 4-dinitrophenylhydrai~~ &gent are added. After dilution d i t h 25 ml. of water, the hydrazone is filtered off washed with water, and recrystallized from alcohol. The melt& point identifies the carbonyl compound corresponding to the alcohol.
Figure 1. Portion of Completed Scale on Spectrometer
Chart
The use of
The procedure was successfully tested on the monohydric primary and secondary aScohols through the pentanols, and in addition, ethyl isopropyl carbinol, I-hexanol, I-heptanol, I-octanol, and 2-octanol. Tertiary alcohols reduce the permanganate very slowly and the products are mixtures of carbonyl compounds. Any easily oxidized substances or carbonyl compounds interfere with the procedure. Perchloric acid is used in preparing the 2,4-dinitraphenylhydraeine reagent for t wo reasons: The reagent is readily soluble the airl nf in aqueous perchloriL+ orirl aiithml+ ll._.._II I.n r w a n i n anlwonts: ~~, d the orecidtation of the hvdrseone is mare ramid and more mrilete when perchloric acid is used as it catalyst. Tk,ere is no ng;er unless the solution is heated for extended periods IYED
are made in obtaining the d-values corresponding t o the peaks of the chart. After the scale is set on the ohart and carefully matchedwiththemlLjor5"lines, the&valueof agivenpeakkisread directly from the soale. This direct reading of &values greatly reduces the fatigue involved in analyzing spectrometer charts. Accurate estimation of two-theta, conversion t o theta, and reference t o the tabulated d-values, as usually practiced, are no longer necessary. Possible errors in completing any of these steps are thereby eliminated. Subsequent to the development and use of such scales by the writer, and during the preparation of this paper, a description of somewhat similar scales was published by Brown ( 1 ) . His soales differ somewhat in applioation from those of the writer. The charts described by Brown me designed to Serve merely as an improvement over the usual tabulated data in eliminating the necessity for continually solving the Bragg equation. Those described in this paper, on the other hand, are contact scales, intended primarily for use on spectrometer charts. Thus applied, they possess the additional advantage of giving the d-values directly, without necessity for measurins the Braes anneles. Should the user prefer, the systt:m of d-value int er vals employed by Brown could he substitutedI for that used I3Y the writer in subdividing such contact scales.
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July 24, 1947.
Bromine Number of Olefinic Hydrocarbons" [ANAL. C ~ E M . , 19, 869 (1947)l the titles for the three figures on page 869 should he: Figure 1. Effect of Excess Reagent on Bromine Number. Figure 2. Effect of Temperature on Bromine Number. Figure 3. Effect of Time after Addition of 1-MI. Excess Reagent on Bromine Number. On page 871, column 2, line 9 should read Figure 2 instead of Figure 1. Line 18 refers t o Figure 3 instead of Figure 2. Line 24 should read "compounds gave absorptions very close t o theoretical." Line 25 should hegin Figure 1 instead of Figure 3 Line 37 should read Figures 1 and 4 instead of Figures 3 and 4.
HZRRERT L. JOHNSON
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R I C ~ A RA.DCLARK Sun Oil Co. Norwood. Pa.
IlTERATlIRE ClTED . ~~
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(1) Brown.O.E..J. AppliedPhys., 18,181-8 (1947). (2) "Internstional Tables for Determination of Cryst-.
ll.lll-.-l,
Vol.Z,AnnArbor, Mioh.,EdwardsBros., 1944.
R s c e l v ~ nSeptember 22, 1947. Contribution from the Research Laboratories of the Ceramic Division of the Champion Spark Plug Compkny.
Ip the article "Evaluation of Catalysts for Catalytic Cracking" [Resoorla, Ottenweller, and Freeman, ANAL.CHEM.,20,196 (1948)l reference (1) should read: Alexander, Julian, Jr., and Shimp, H. G., Natl. Petroleum News, 36, R5378 (1944).
