V O L U M E 2 3 , NO. 10, O C T O B E R 1 9 5 1
1491
aliquot of the original 100-ml. volume. If the ore contains a higher percentage, dilute the 10-ml. :diquat to the appropriate concentration rangc and test an aliquot of the diluted solution. Pipet the 10-ml. aliquot of appropriate dilution into a 50-nil. volumetric flask. .kid from buret 7 nil. of sodium sulfite solution :tnd 8 ml. of potassium iodide solution, and dilute to the mark. Mix xell. The color develops inimediately and is stable for sevcral days. Sample4 ma> I x read in the elcctrophotometer nt once uqing a 42,513 filter.
quired to obtain 811 aliquot of bismuth concentration in the range for color that accuracy was impaired. The proceduie was checked using seven tungsten ore concentrates that had been analyzed by Ledous and Co. by other methods (Table 11). It can be concluded that this method is applicable for the determination of bismuth in tungsten ores. LITERATURE CITED
PRACTICAL APPLICATION
This procedure M R used for ore products varying from 0.03 to Excellent material balances were consistently obtained when the products from ore beneficiation all contained IPPS than 10% bismuth. JJ-hen higher grade bismuth concentixtes n-cre produced, hon-evw, such great dilutions were re-
60% bismuth.
(1) Scott. IV. W..“Standard Methods of Chemical Analvsis.” Voi. ’ 1, PP. 15O-61, Kew York, D. Van Sostrand Co., 1939:
( 2 ) Sproull, R. C., and Gettler, A. O., IND. ENG.CHEM.,ANAL.ED.,
13,462 (1941). ( 8 ) IT-iegand, C. J. JV,,Lann, G. H., and Kalich. F. V., Ibid., 13, 912 (1941). R~~~~~E D l I a r c h 6,10:0.
New Color Reaction for Detection of the Methyl Ketone Group JIRO ADACHI Chemical Laboratorj; Tokyo Bunrika Cniaersity, Tokyo, Japan l 0 I i the detection of the CH3CO- or CH$CH(OH)- groups Lieben’s iodoform reaction ( 7 ) has been widely used. This reaction, however, which relies upon smell, often give?; m i Iiguous rcsulte, TThich are attributed to the anesthetic action of the iodoforni formed upon the olfactory nerve. The color renc-
’ (d),
HOCHz-CHz-CH2
tiori proposed hj- Lustgarten or Klar ( 7 ) , which develops :I red coloration when the Lieben’s mixture-a methyl ketone and potassium hypoiodite solution-is heated with the addition of resorh o l , seems to be a disagreeable procedure. Fujin-am ( S ) ti,e:ited a guinea pia with chloroform, hy inhaln-
CH.&OO-CHz-CHr-CH,
p
c
1
H
/“‘CH,
/
’0‘
I,,, ‘0
.4cetylation
A _ T I
Egonol ( 6 ) .
\
HOCH -CHz-CH2 Reimer Tiemann reaction CH3COOCH2-CHz-CH
Saponify Styraxinolic aldehyde
acid CH1COOCHzCHzCHz
HOCHZ-CHI-CH~
Styraxinolic
acid
Figure 1.
VI
4
Acetic acid ++ Piperonylic acid
Saponify
Acetyl styraxinic acid
Conipounds Containing Neither .\Iethj I Ketone S o r .\leth\ I Carbinol Groups, But Showing Positive locloforni Heactions
ANALYTICAL CHEMISTRY
1492 tion or by intravenous injection, :inti extracted thc 01’g:niis of the animal with alcohol. IVhen this alcoholic extract, whicli contained traces of chloroform, was mixed with a 10% aqueous ~ o l u tion of sodium hydroside and 2 ml. of pJ.ridiiie : ~ n d t~oilcd,n bright blue-red coloration dcvelol)ctl inimcdiati~l~~. Cole ( 2 ) estended this color reaction to a colorinictric dc~tcriiiinationof chloroform. He could detect 0.00017, of chloroforni in an q u r OUR solution or in an extract of animal tissues. A new color reaction, suggested h!. Fujiwarn’s discovery, has been elaborated by the author, and is dcscribetl here. IVhen :I compound that contains methyl ketone or methyl carbinol groups is treated with alkali hypochlorite or hypobromite and the whole is heated with the addition of pyridine, a carmine red or pink color immediately develops. In this reaction pyridinc is not the fiole reagent; pJ.iidine, quinoline, and their homologs are also available. Hypoioditc, however, is not applicable i n lieu of hvpochlorite or hypohwrnitc. For conveiiicncc the reaction with hypochlorite is called the “chloroform rc:iction” (C) and that with hypohromite the “bromoform reaction” (13). The sign means a positive color reaction and the sign ” - ” dcnotes no caolor reaction. Three different cases were csamined. Compounds Showing Positive Iodoform Reactions. Acetone, ethanol, acetaldehyde, isopropyl alcohol, acetophenone, p-hydroxyacetophenone, aeetoveratrone, acetopiperonc, and ~V-acetyl-a,p-diphenglindol. Both bromoform and chloroform react’ions were positive in all cases. Compounds Containing Neither Methyl Ketone nor Methyl Carbinol Groups, but Showing Positive Iodoform Reactions. Styrasinolic acid (6) (B+, C+), acetyl styraxinic acid (6) (B+ C - ) &,a-dibenzoylethane (7) (B+, C+), cholesterol ( 1 ) (b+, dibenzalacctone ( 1 ) ( B + , C f ) , &-phenyl-[& methyl, phen)-l]-ethyle~ieglycol( 1 ) (B+, e+),citric acid ( 7 )
”+”
6-),
(B-, C-).
Compounds Containing Neither Methyl Ketone nor Methyl Carbinol Groups and Showing No Iodoform Reactions Consequently. Thirty-four compounds of different constitutions
were chosen a t random. Of these, only carbazole showed a positive bromoform reaction but no chloroform reaction. Owing to the fewer exceptional reactions observed, thc chloroform and bromoform reactions seem to esccl the iodoform reaction. EXPERLMENTAL
Preparation of Hypochlorite Solution. Bleaching powdor ( 4 grams) wm mixed with water (25 ml.), and sodium carbonate solution (6 grams of sodium carbonst,e with water of crystallization and 15 ml. of water) was added and well stirred. The resulting calcium carbonate was filtered off. The slightly yellow solution thus obtained was applied for the chloroform reaction. Preparation of Hypobromite Solution. Bromine (2 grams) was dissolved in 50 ml. of 0.6 hr potassium hydroxide solution. The resulting solution was available for the bromoform reaction. Manipulation of Analysis. A small amount of t’he compound which contains the methyl ket.one group (one drop, if liquid) was taken in a t,est tube, 1 drop of hypochlorite (chloroform reaction) o r hypobromite (bromoform reaction) solution and 2 drops o f pyridine were added, and the whole was warmed over a tree fame. A carmine red or pink color promptly m:icle its aprmr:111ce. ACKNOWLEDGMENT
The author is indebted to Sin’iti Eiawai, a t whose suggestion this work was undert’aken and who supplied many valuable spwimens. LITERATURE CITED
(1) .kclachi. Jiro, unpublished data. ( 2 ) Cole, W. H., J . Bid. Chem., 71, 173 (19%). (3) Fujiwara, K., Sitzber. Naturw. Gea. Restock., 6, 33 (1916). ( 4 ) Kamlet, Jonas, 1x11. ENG.CHEX, A w \ r . . Eo.. 16, 3132 (1944). (5) Kawai, S., e t al., Ber., 72, 369 (1939). ( G ) Ibid., p. 1146. (7) JIeyer, Hans, “Analyse uiid Iionstitut.ionscrmittluiig organischer Verbindungen,” Gth Aufl., pp. 305. 306. Berlin, Julius Springer, 1938. RECEIVED December 1, 1950.
Determination of Nitrogen by Micro=Dumas Procedure EL3IEH F. SHELBERG iibbott Laboratories, .\*orth Chicago, 111.
’M-ERAL modifications of the original micro-Dumas inrthotl have been described recently (1-4, 7’). The usual Dumas method ordinarily furnishes erratic result,sunless the sample burning and carbon dioxide flow are carefully controlled. A proceclure currently in use at Abbott Laborat,ories obviates the necessitj. for slow sample burning and slow gas flo~r-. The analysis nisi. tw completed in approsimately 10 minutes (not including ~r-eighinp time) and has provided results \Tithin 0.1% of theory on hundreds of analyses by scveral analysts. This fast procedure involvcs the use of two combustion tubes, and is particularly adaptable to routine analyses in rapid succession, as it is not necessary to cool the tube that is heated in the furnace between determinations. APPARATUS
T h e apparatus for the rapid Dumas procedure is assernhltd illustrated in Figure 1.
:LP
Carbon Dioxide Generators. Two standard dry ice generators or chemical generators, A and A’, include stopcocks 1 :1nd 5 , respectively. Removable Combustion Tube. A standard diameter, 2.!6-111m. Vycor combustion tube, B , contains a semipermanent packing comprising a small amount of asbestos a t the end, 80 mm. ot coarse (pieces 3 to 5 mm. in length) cupric oside, and a small amount of asbestos which is tamped on top of the cupric oside. The remainder of tho tube accominotlates a misture of the
weighed sample and 40- to 100-mesh cupric oside. I t is convenient to have several auxiliary tubes beside the balance case for use in a series of analyses. Before they are used, freshly packed tubes should be heated a t approximately 800” C. (blast lamp) for a few minutes while t’hey are flushed with carbon dioside. No wire gauze is ever used around the removable combustion tube, but its surface should be made rough with an emery cloth, as such treatment seems to preclude star formation and cracking when the tube is placed over t,he blast lamp. Asbestos Shield. The shield, C, is plnced directly over combustion tube B. Stationary Combustion Tube. A st:indard diameter, 380-mm. T-ycor combustion tube, D,contains a permanent packing similar to Pregl’s conventional tube (6). This tube is packed as follows: A small asbestos plug 3 to 4 mm. thick is compressed into the neck of the combustion tube, followed by 130 mm. of coarse cupric oside. Another asbestos plug 2 to 3 mm. thick is inserted, followed b p . 40-nim. layer of copper vr-001 or copper wire. A t’hird asbestos plug 2 to 3 mm. thick is tamped onto the copper, followed by another layer of 80-mm. coarse cupric oside. A fourth asbestos plug 3 to 4 mm. in length concludes the permanent filling, which has a total length of 250 mm. Combustion Furnace. A conventional micro combustion furnace, E, is used. Azotometer. B conventional microazotometer, F, is used. Burners. Two blast lamps, G and G’, capable of operatin at SOO” C. are placed under combustion tube B , as indicated in h g ure 1, at the start of a combustion. (Blast lamps with burner tip 5 2 are now used, made by Anderson and Forrester Co., Ilenver, Colo.)
