V O L U M E 27, NO. 5, M A Y 1 9 5 5
835
cipitate formed i n oxidations of glucose with ditellurato cuprate (111) contained tellurite. Therefore, again competing oxidations were present, which indicated t h a t further work with glucose was futile. The oxidation of tartrate ion starting with disodium tartrate dihydrate b y either diperiodnto cuprate(II1) or ditellurato cuprate(II1) was found t o be subject to the same limitations as the oxidation of glucose. The rate of oxidation was reasonable, hut highly colored solutions and precipitates prevented the use of a visual end point. No break was found in t h e plot for t h e potentiometric titration and titrations with the dead-stop end point were not reproducible. In addition iodate was found in t h e mixture from diperiodato cuprate(II1) oxidation. In connection with the oxidation by t h e complexing anion, the 2 to 1 ratio found in the copper(II1) complex is not necessarily found in t h e compound which can be isolated containing copper G ) ~ been isolated (11). For esample, Cug(I06)*and H ? C U ~ ( I Ohave (10). Hence periodate is avai1:tk)le for oxidation as soon as any c.oppcr(II1) is reduced if not hefore.
product composition, and the possible competition via tlie oxidizing action of the complexing anion. A t the milligram level these difficulties may well be minimized so t h a t empirical methods yield satisfactory results ( S , 4 ) .
CONCLUSION
REcrrrrn for reriew September 9, 1954. Accepted Xoremher 1 6 , 1954. Presented before the Division of Analytical C h e n ~ i s t r ya t t h e 126th hfeeting of the AMERICASCIIEI\IICAL SOCIETY, N e i r T o r k , N 1. Abstracted in part from the X S . Thesis submitted b y Donald -1.Ke>-\vortli, J u n e 1!354.
1pplic‘:ttionc: of copper(II1) oxidation a t the millimole level are liiiiitcd 1)v the difficulty of enti-point detection, the uncertainty of
LITERATURE CITED
(1) Beck, G., Anal. Chim. Acta, 9 , 241-7 (1953). (2) Beck, G., Mikrochemie aer Mikrochem. Acta, 35, 169-73 (1950); 38, 1-10 (1951); 39, 22-9, 147-51 (1952); 40, 258-63 (1953). (3) Ibid., 36, 245-50 (1950). (4) Ibid., 38, 152-9 (1951). (5) Crouthamel, C. E., Hayes, A. AI., and Martin, D. S.,J . Am. Chem. Soc., 73, 82-7 (1951). (6) Crouthamel. C. E., IIeek, H. V.,Martin, D. S.,and Banks, C. Si.. Ibid.,71, 3031-5 (1949). (7) Lister, 11. W., Can. J . Chem., 31, 638-52 (1953). (5) Nalaprade, L., Compt. rend., 204, 979-80 (193T). (9) Nalatesta, L., Gam. chim.ital., 71, 467-74, 550 (1941). (10) Smith, G. F., “Periodic Acid and Iodic Acid,” 5th ed.. p. 5, G. F. Smith Chemical Co., Columbus, Ohio, 1950. (11) Stone, K. G., and Scholten, H. G., Ax.4~.CHEM.,24, 671-4 (1952). (12) Urtiss, hl., Rec. tray. chim., 44, 425-34 (1925).
Determination of Zirconium in Magnesium Alloys Using p-Bromo- or p-Chloromandelic Acid ROLAND A. PAPUCCI,
F. C.
Broeman and Co., Cincinnati 70, O h i o , and
JOSEPH J. KLINGENBERG, X a v i e r University, Cincinnati 7, O h i o Successful application of p-bromo- and p-chloromandelic acids to the determination of zirconium in steel and aluminum alloys suggests a similar applicaLion to zirconium-containing magnesium alloys. Using these reagents, a rapid and reliable procedure was developed which can be applied to all types of magnesium alloys.
B R T I M E conditions and the constant search for high temperature alloys for use in the turbojet industry have led to a more complete study of magnesium base alloys. T h e addition of small amounts of zirconium to magnesium and magnesium alloys was found to improve the operating temperatures and the grain structure without affecting the creep resistance or machinability. T o meet this and other neiT metallurgical advances, accurate nnd more rapid methods for the determination of zirconium in sinal1 concentrations are needed. The phosphate method ( I ) is subject to error in t,he low concentration range and requires excessive time especially when the zirconium content is lower than 0.25Yo, T h e feasibility of using p-bromo- or p-chloromandelic acid for the determination of zirconium in steels and in aluminum alloys has been demonstrated ( 2 , 3 ) . T h e development of a method utilizing these reagents which would combine speed with accuracy and which could be applied to all types of magnesium alloys was undertaken. Such a method might also compare favorably with the alizarin red S colorimetric method (4)which is also available for the determination of zirconium in magnesium. Zirconium occurs in commercial magnesium alloys in acidsoluble and acid-insoluble forms. T h e strength characteristics of the specific alloys are related to the soluble zirconium content of the alloy. The acid-insoluble zirconium is usually small in
conip:trison to the acid-soluhle content. I n some cases the determination of the total zirconium conteqt is desired: in others both the amount of acid-solulile and acid-insoluble zirconium. Consequently two procedures n ere developed. One procedure describes the determination of acid-Foluble zirconium only. T h e other describes the determination of the soluble and insoluble forms. Both are applicable to all types of magnesiuni :illoys. PROCEDURE
Determination of Soluble Zirconium. A sample of 0.25 to 2.0 grams (amount depending on the zirconium content) is placed in a 250-ml. beaker. An amount of hydrochloric acid (1 t o 4) corresponding to 80 ml. per gram of alloy dissolved is added The beaker is covered with a watch glass and warmed. When the reaction is complete, the contents of the beaker are cooled to room temperature and the watch glass is rinsed with small amounts of n-ater. The solution should be clear. If a residue can
Table I.
Determination of Acid-Soluble Zirconium in Magnesium Alloys
Zirconium Present,
Zirconium Found, % p-Chloromandelic acid
Sarnple
%
Phosphate
Alizarin red S
1
0.44
0.42
0.44
2
0.46
0.45
0.45 0.44
3
0.48
0.46 0.47
0.47
4
0.95
0.9.5 0.95
0.97 0.97
0.44 0.44 0.47 0.47 0.47 0.48 0.48 0.47 0.48 0.98 0.97 0.98 0.98 0.98
p-Bromomnndeiic acid 0 4.5 0 45 0 46 0.49 0 48 0.98 0.98 0 98
ANALYTICAL CHEMISTRY
836
zirconium is to be determined, the volume adjusted to about 50 ml. If the total zirconium content is to be determined, Zirconium Found, % p-C hlorop-Bromothe solution is combined with Alizarin Phosphate red S mandelic acid mandelic acid the original filtrate. Fifty milSamplea Sol. Insol. Sol. Insol. Sol. Insol. Sol. Insol. Sol. Insol. liliters of 0.1M p-bromo- or p0.57 0.02 0.56 0.01 0.50 0.02 0.58 0.03 0.58 0.03 chloromandelic acid per 0.25Dow 72480 0.55 ... 0.56 .. 0.58 ... 0.59 0.03 gram sample are added (more 0.58 0.03 if the zirconium content is high 0.58 0.03 in the sample). T h e contents Dow 72992 1.10 55.10 1.09 54.89 1.12 .. .. 1.14 55.22 , , are digested on a hot plate a t 1.14 1.14 55.27 ,, about 80" to 85" C. for a t least 1.12 . 1.14 55.20 .. .. 20 minutes, cooled to room Dow 72993-1 0.20 0.04 0.20 0.03 0.21 0.04 0.04 0.21 0.04 temperature, and filtered on .., 0.20 .. 00 .. 22 11 0.04 0.21 0.04 0.20 0.21 0.04 Whatman No. 40 paper, using Dow 72993-2 0.62 0.06 0.61 0.06 0.62 0.05 0.63 0.06 0.63 0.07 some ashless pulp. T h e pre0.61 0.05 0.03 0.06 cipitate is washed a t least 12 0.62 0.06 times with small portions of 0.63 0.06 warm water, the residue 0.63 0.06 charred in a weighed platinum a Samples and analyses, courtesy of Dow Chemical Co., Midland, hlich. dish, and finally ignited a t 1000" C. T h e residue can also be weighed directly in a tared Table 111. Determination of Total Zirconium in weighing dish after being transMagnesium Alloys Containing Acid-Soluble and ferred from the platinum crucihle. Per cent zirconium is calcuAcid-Insoluble Zirconium lated according to equation. Table 11. Determination of Acid-Soluble and Acid-Insoluble Zirconium in Magnesium Alloys
.
Zirconium Found, % p-Chloromandelic acid
p-Bromomandelic acid
Sample
Phosphate
5
0.47
0.49 0.48 0.48
0.49 0.49 0.49 0.49
6
0.92 0.92
0.93
7
0.89
0.92 0.92 0.93 0.93 0.92 0.92
n
~i
RESULTS
Tables I, 11,111,and I V give t,he results obtained for zirconium in acid-soluble and acid-insoluble forms in various kinds of magnesium alloys using the halomandelate reagents. Comparative results by the alizarin red S and the phosphate method are also included. Transmittance measurements for the alizarin red S method were made with a Model DU Beckman spectrophotometer modified to hold two 100-mm. silica window-Vycor body cells a t a wave length of 510 mp.
0.92 8
0.70
0.73 0.73 0.73
9
0.51 0.51
0.53 0.53 0.53 0.54
0.73
Table IV. Complete Analysis of Magnesium Alloys Containing Acid-Soluble and Acid-Insoluble Zirconium Zirconium calculated as total zirconium Zirconium Found, % p-ChloroCompn. Alloy, Alizarin mandelic % Phosphate red 8 acid Th 2 98 0.70 0.72 Zn 2 25 0.70 0.71 R.E. 0 07 0.71 , . hln 0.06 cu 0 02 Si 0 008 Ni 0 005 ~ \ I K Balance Zn 4 06 0.54 0.5,5 0. J I n 0 12 0.54 0.56 0.55 Cu 0 02 0 57 0.55 0.54 SI 0 008 0,56 Fe 0 005 0 . dti Nl 0 001 0 30 JIg Balance 0.81 Ce 2 89 0.82 0 83 R E . 3 65 0.81 0.82 0 83 Zn 2 GO 0 82
be seen, acid-insoluble zirconium is present. Very small amounts of acid-insoluble zirconium (less than 0.04%) may not be visible to the naked eye. If such a residue is present or suspected, i t is removed by filtration before proceeding. A solution of 50 ml. of 0 . M p-bromo- or p-chloromandelic acid per 0.25 gram of sample is then added with constant stirring. T h e corresponding amount of pure solid reagent may also be added directly to the solution. T h e contents are stirred, digested a t about 80" to 85" C. for 20 minutes, cooled, and filtered through Whatman No. 40 paper. T h e precipitate is washed 10 to 12 times with water, charred slowly in a weighed platinum crucible, and ignited a t 1000" C. T h e difference in weight represents zirconium oxide. T h e residue can also be weighed directly in a tared weighing dish after being brushed from the platinum crucible. weight ZrOz X 0.7403 X 100 % zirconium = weight of sample
A h
Cu
SI Fe SI X g
Determination of Soluble and Insoluble Zirconium. A 0.26t o 2.0-gram sample is placed in a 250-ml. beaker, the amount used depending on the approximate zirconium content. An amount of hydrochloric acid (1 t o 4 ) corresponding t o 80 ml. per gram of alloy dissolved is added slowly until the vigorous reaction has ceased. Sulfuric acid ( 1 to 4) may be used in place of the hydrochloric acid. T h e contents are warmed t o ensure complete reaction. Insoluble zirconium, not actually alloyed with the magnesium, will be evident a t this stage appearinq as minute dark particles. Very small amounts (less than 0.04yc) may not be visible. T h e suspension is cooled and filtered on Whatman Y o . 40 paper. T h e soluble zirconium in the filtrate can be determined by the described procedure. T h e insoluble matter and filter paper are transferred to a platinum dish, charred s l o ~ l yand , ignited a t 1000" C. T h e residup is fused B ith 1 to 3 grams of potassium acid sulfate, dissolved in hydrochloric or sulfuric acid (1 to 1 ) and, if only insoluble-
0 10 0 03 0 006 0 005 0 001 Balance
0 83 0 83 0 83
p-Bromomandelic acid 0.73 0 73 0.73 0.73 0 73
0.57
0 0 0 0
83 8.3 83 84
T h e halomandelate method was considerably more rapid than the phosphate method and equal to if not better than the colorimetric method. The authors prefer the halomandelate procedure. LITERATURE CITED
Hillebrand. W. F., a n d Lundell, G. E. F.."hpplied Inorganic Analysis," pp. 446-51, Wiley, h'ew York, 1929. (2) Klingenberg. J. J., and Papucci, R. A , . .\s.\L. CHEM..24, 1 8 6 1 (1)
11952). (3) Papucci. K. A . , Fleishman, D. 31.,and Klingenherg, J. J., Ibid., 25, 1758 (1953). (4) Wengert, G. 13.. Ibid., 24, 1449 (1952). RECEIT ED for re%iewSeptember 3, 1954.
Accepted Noveinher 16, 1954.
