T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
304
Vol. 14, No. 4
Tests of an Iodine Pentoxide Indicator for Carbon Monoxide’” By S.H. Katzs and J. J. Bloomfield4 CHEMICAL DIVISION,PITTSBURGH EXPERIMENT STATION, BUREAUOF MINES,PITTSBURGH, PA.
The “Hoolamite” or activated iodine pentoxide indicator for carbon monoxide is frequently used by engineers of the Bureau of Mines engaged in mine-rescue and recovery operations. The tests described in this paper were made to determine its accuracy. The indicator gives positive indications for carbon monoxide in air in concentrations oj 0.07 per cent or more. I n afew instances there were no indications with 0.07 and 0.08 per cent. No failures to indicate occurred at higher concentrations. Two tests with 0.10 per cent CO in air indicated 0.10 and 0.05 per cent; eight tests with 0.15 per cent gas gave determinations ranging from 0.10 fo 0.23 ger cent, with an average of 0.16. At higher concentrations the variations were proportionally about the same. The results of tests with air containing wood smoke and with flue gases aueraged a little high. LOWoxygen or high carbon dioxide in the gas tested did not decrease the action of the Hoolamite. No diflerences were found in tests made at ordinary or freezing temperatures, in daylight, or in artificial light. Acetylene, alcohol, ammonia, benzene, ether, ethylene, gasoline. hydrogen chloride, hydrogen sulfide, natural gas containing members higher than methane, and water produce interjering effects if allowed o enter the sensitive material. When the gases are first passed through the fresh actiuated charcoal, interfering substances are absorbed and no error results from their presence. Carbon dioxide, carbon tetrachloride, chlorine, methane, nitrogen peroxide, phosgene, and sulfur dioxide do not interfere. Determinations of carbon monoxide are easily made in less than one minute, and no skill is required. Only one person in thirty has beeh found to haue dificulty in determining the color shades. The instrument is proving a ualuable aid in mine-rescue and recovery operations after $res and explosions, and f o r testing air around blast furnaces, gas producers, water-gas and coal-gas plants, and other places where carbon monoxide occurs. It also may be used to promote furnace economy by indicating carbon monoxide in flue gases.
OOLAMITE is a mixture of iodine pentoxide and fuming sulfuric acid on granular pumice stone. In contact with carbon monoxide, it changes-owing to the liberation of iodine-from the original white to increasing depths of bluish green, then violet-brown, and finally black, depending upon the concentration of carbon monoxide. The indicator (Type B, Figs. 1 and 2, in article by Hoover 6) consists of a tube of activated charcoal, through which gas is drawn by means of a rubber hand bulb. It then discharges through a small glass tube containing Hoolamite. The charcoal removes any gas other than carbon monoxide which may produce a false test, unless it is present in large quantity. Interfering dusts and mists are stopped by cotton-wool filters, after the charcoal and before the Hoolamite. Five permanent colors on pumice stone are placed for comparison in a sealed glass tube alongside the Hoolamite. According to the patents,@Hoolamite may consist of:
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Iodine pentoxide, 10 parts Fuming sulfuric acid, 50 parts (60per cent SO*) Pumice granules, 30 parts (20 to 40 mesh) Iodine, 0.25 to 2 per cent
Per cent 11 55 33 0.25 to 2
A larger proportion of fuming acid is claimed to increase the sensitivity, and the iodine is added for the same purpose. Analysis6 of some of the material used in these tests gave 12.29 per cent iodine pentoxide, 51.89 per cent fuming sulfuric acid (47 per cent SOa), and 35.82 per cent pumice granules. No free iodine was detected. Since moisture causes deterioration of the Hoolamite, it is put up in small glass tubes tapered at the ends and sealed. The tips are easily broken open with the lingers. In using the detector, the bulb is squeezed three times, the tube of Hoolamite is inserted, the bulb is squeezed 10 times more (10 squeezes of the bulb deliver 350 * 50 cc. of gas), and the carbon monoxide is estimated. Should the color be indistinct, 20 squeezes are advisable. The carbon monoxide is then placed at half the corresponding shade for 10 squeezes. TESTS FOR CO IN AIR Table I gives the results of tests with CO-air mixtures. Fig. 1 shows the averages of determinations, compared graphically with results of Haldane analyses. Less than 0.07 per cent of CO in air gave no noticeable color change; in a few instances there was no indication with 0.07 or even 0.08 per cent, but no failures to indicate were found in concentrations higher than these. Of two tests with 0.10 per cent CO, one indicated only 0.05 per cent. Eight tests with 0.15 per cent gave determinations ranging from 0.10 to 0.23 per cent. At higher concentrations the deviations were proportionally about the same as those mentioned. The averages of several determinations
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1 Received 2
June 22, 1921. Published by permission of the Director, U. S. Bureau of Mines.
a Assistant Physical Chemist, Pittsburgh Experiment Station.
‘ Junior Chemist, Pittsburgh Experiment Station.
C. R. Hoover, “The Detection of Carbon Monoxide,” THISJOURNAL, 1s (1921), 770 6 A. B. Lamb and C. R. Hoover, “Absorbent,” U. S. Patent 1,321,061, Nov.4,1919; “Gas Detector,” U. S. Patent 1,321,062, November 4, 1919. 6
VIRBON M O N O X I D E
By
HALOANE ANALVSI8,PER
CENT.
FIG. AVERAGES OR CARBON MONOXIDE DETBRMINATIONS WITx INDICATOR COMPA$ED TO ANALYSES WITH HALDANE APPARATUS
~7
Analysis by W. A. Selvig.
THE JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
April, 1922
CO by Haldaqe Analysis 0. Per cent 0.02 18 0.02 19 0.02 20 0.05 57 0.05 58 59 0.05 60 0.06 61 0.06 0.07 i5 0.07 16 0.07 17 25 0.07 0.07 26 0.07 27 62 0.07 66 0.07 63 0.08 0.08 67 0.08 83 0.08 84 0.08 86 0.08 86 0.08 87 0.08 88
%
EST
64 68 65 69 49 50 51 52 53 54 55 56 40 41 12 13 14 79 80
0.09 0.09 0.10 0.10 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.22 0.22 0.23 0.23 0.23 0.28 0.28
305
TABLEI-RESULTS OF DETERMINATIONS OP CO I N AIR (COI contents approximately one-fifth those of CO. Bulb squeezed 10 times unless otherwise stated) C O b y CO by CO by Haldane IndiIndiTEST Analysis cator Observer cator Observer REMARES No. Per cent Per cent No. Per cent No. REMARKS 81 0.28 0.23 0.00 3 )Test a t O o C. 82 0.28 0.16 0.00 10 Av. 4 tests=0.27 per:cent 0.00 3 3 9 0.30 0.23 0.30 10 0.34 10 20 squeezes 0.30 3 0.34 11 0.00 3 0.30 0.23 32 Tube used day previous, rubber:capped 24 hrs. 0.00 o.oo 1; squeezes 0.30 33 0.34 14” Av. 5 tests = 0.30 per cent 28 0.56 0.23 29 0.56 0.34 Old tubes from Chemical warfare Service 38 0.56 1.80 31 39 0.56 0.68 AV. 4 tests = 0.76 per cent 3 7.5 0.64 0.45 3 76 0.64 0.45 3 Test7,at:do C. 77 0.64 0.68 0.09 3 20 squeezes 3 78 0.64 0.68 0.00 16 Av. 4 tests=0.57 per cent 0.10 7 0.10 ’ 4 6 16 0.84 0.45 0.10 4 Test a t O o C. 7 0.84 7 0.68 0.08 9 3 Av. of 3 tests = 0.60 per cent 0.68 0.84 8 0.05 3 20 squeezes 0.95 0.90 11 36 0.04 4 20 squeezes test at Ooi,C. Tube.used day previous, rubber capped 24 hrs. 3 0.95 37 0.90 Av. 8 tests 0.07 per cent 3 0.97 72 1.44 0.075 4 20 squeezes 4 0.97 1.80 73 0.05 3 Av. 2 tests = 0.06 per cent 4 Test a t 0’ C. 74 0.97 1.62 0.12 15 20 squeezes Av. 3 tests=1.44 per cent 0.05 4 Av. 2 tests = 0.09 per cent 7 1.06 1.08 21 0.10 3 3 1.06 1.08 22 0.16 4 3 1.26 1.26 23 13 1.26 1.26 24 Test made in artificial light 4 Tubes used previous day, rubber capped24 hrs. 0.45 1.42 34 3 0.68 1.42 35 Av. 2 tests ~ 0 . 6 per 7 cent 0.10 5 Av. 8 tests=0.16 per cent 1 1.35 3 1.49 }Old tubes from Chemical Warfare Service 3 1.35 4 1.49 o.45 0.45 5 Av. 3 tests = 1.35 per cent 1.35 5 1.49 0.23 5 5 2.06 30 1.51 0.23 4 7 Old tubes from Chemical Warfare Service 1.51 2.06 31 3 Av. 3 testsc0.23 per cent 0.23 3 1.35 1.91 1 0.34 4 14 Av. 2 tests = 1.72 per cent 2 2.06 1.91 0.34 4
7”
1
g: %
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1
3”
3”
with newly opened tubes, as shown in Fig. 1, in general were closely correct; the greatest deviation was in the case where three tests with ,0 .97 per cent carbon monoxide gave an average indication of 1.62 per cent. The data in Table I were obtained in many instances with tubes used repeatedly after fading from previous use. Used tubes were apparently as good for six or eight determinations BS fresh ones, but thereafter the absorbed water showed a distinct darkening at the inlet end. Tubes that after use had been kept over night, capped with tight rubber caps, generally were found to give accurate determinations, but in one instance results were too low. Tubes that had been kept capped a week lost much sensitivity. Tests indicated by crosses in Fig. 1 were made with a few old tubes that had been prepared by the Chemical Warfare Service three years before. Results were less uniform, though generally their sensitivity w&s higher than that of the tubes now made commercially. Tests at freezing temperature and those made in artificial light were as accurate as those made under ordinary conditions. None of the twenty-six persons who made tests had any difficulty in distinguishing the shades, though it has been stated that one man could distinguish no color for carbon monoxide below 0.20 per TESTS FOR CO IN SMOKE Since gases, vapors, and smoke from fires may contain many organic compounds which can produce the colors, a test was made of the instrument for determining carbon monoxide in wood smoke. The smoke was so dense that it was impossible to see more than two feet through it. 8 D. Harrington and B. W. Dyer, ‘‘Test of a Carbon Monoxide Detector Which Shows Gree? When That Gas Is Present, Coal Age, 19 (1921), 269.
Two Haldane analyses showed 0.29 per cent carbon monoxide, while the indicator gave the following results: 3 7 16 12 12 8 2 0.34 0.23 0.45 0.46 0.45 0.45 0.34 0.39
Observer No. Estimated,CO, per cent AVERAGE
The average of 0.39 per cent is 0.10 per cent more than the Haldane analysis, but the difference is not much larger than shown by some of the previous tests. AN observers determined the concentrations as within the two near shades of the scale used.
TESTS WITH FLUE GASES Flue gas differs from those preceding in that it contains comparatively high proportions of carbon dioxide and low oxygen; in the previous tests, the oxygen was high and carbon dioxide low. The gases tested below were taken from the breaching of a boiler furnace. Some carbon monoxide was added to one sample in order to give higher percentage than the furnace delivered. An analysis by the Haldane apparatus gave 0.01 per cent CO, 7.98 per cent COP, 10.98 per cent 02, and 81.03 per cent Nz. Results by the indicator were: Observer No. Squeezes Analysis by indicator, per cent AVER~GE
3 10 0.00 0.025
16 10
3 20
20
0.00
0.05
0.05
9
In another test, the Haldane apparatus gave 0.22 per cent
CO, 5.41 per cent COz, 13.66 per cent 02, and 80.71 per cent Nz, and results by the indicator were: Observer No. Squeezes Analysis by indicator, per cent AVERAGE
3 10
4 10
18 10
20 10
22 10
19 10
23 10
21
10
24 10
0.34 0.34 0.23 0.34 0.23 0.34 0.23 0.23 0.28 0.28
