V O L U M E 23, N O . 7, J U L Y 1 9 5 1
1011
Table 1. Comparison of Sulfur Results Obtained by Titrimetric-Oxygen Bomb Method with Theory or ASTM Values Sample
Comparison Method and Value
TitrimetricOxygen Bomb Result
hlotor oil
D 894-48T
IR
0 0 .. 22 00 0.20 0.20
Cutting
D 129-44
0.51 0.51 0.47 0 50
0.49 0 51 0.49 0.50
Xlotor oil
D 894-48T
Heavy lube oil
D 8o4-48T
0.62 0 6fi 0.6.5 0 64 0.87 0.89 0.8.5 0.8;
Diesel oil
n
0 60 0.60 0 GO 0 60 0 86 0 8Y 0 88 0 88 1.16
0.18 0.21 0.19
n 01:
Cutting oil
EY-U
1,16 I 14 1 , 13
D 128-44
1 22 1 48 1.4U
1
Fuel oil
1) 12SJ-44
io
1.11 1 12
1.10 1 11
1 47 1 . .5(1 1 ,;(I 1 49
1 84 1 81
I.i H 1.i 8 1.80 1 79 2.40 2.42 “39 1.40
1 80 1.78
leum Products and Lubricants.” hlethotl D 90-47T, ASTM Committee D-2, 1949. Ibid.i Method 129-49. (6) Ibid., “Proposed Method of Test for Sulfur in Petroleuni Products by the Carbon Dioxide-Oxygen Lamp Method.” p. 1330. (7) Bssoc. Offic. Agr. Chemists, “Official and Tentative Methods of Analysis,” p. 126, 1945. (8) Brewster, E. L., and Rieman, Wm., 111, IND. Esc,. CHEM., AN.4L. ED.,14, 820 (1942). (9) Brunjes. H. L., and Manning, AI. J., Ibid., 12, 718 (1940). (IO) Callan, T. P., and Toennies,G.,Ibid., 13,460 (1941). (11) Carius, L., Ann., 116, l(1860). (12) Dennstedt, >I., Ber., 30,1590 (1897). (13) Elek, A., andHill, D. W., J. Am. Cheni. Soc., 55, 3479 (1933). (14) Emich, F., and Donau, J., Monatsh, 30, 764 (1909). (15) Evans, R. J., and St. John, J. L., IND.ENG.C m x . A N ~ LED., . 16, 630 (1944). (16) Field, E., and Oldach, C. S., Ibid., 18, 668 (1946). (17) Fogo, J. K., and Popowsky, hI., ANAL.CHEW,21, i34 (1949). (18) Foster, bI. D., IND. ENG.CHEM.,ASAL.ED.,8, 195 (1936). and Krekeler, H., -4ngew. Chem., 46, 103 (1933). (19) Grote, W., (20) Hallett, L. T., and Kuipers, J. W., IND. ENG.CHEM.,ANAL.ED., 12,360 (1940). (21) Heinemann, G., and Rahn, H. IT.,Ibid., 9,458 (1937). (22) Kirsten, TV., Mikrochemie, 35, 174 (1950). (23) Kochor. S.J..hD.EXG. CHEM. . AN A L . E D . . 9.381 (1937). (24) Lee, 9. k..Ti’allace, J. H., ,Jr,, Hand. IT. C’., and Hannay. S . B.,
.
Ihid.. 14. - 839 - - - (1942). 125) Luke, C . L., Ibid., 15, 602 (1943) (26) Mahoney, J. J., and hlichell, J. H., f b r t l . 14, 97 (1942) (27) Jlanov. G. C.. and Kirk, P. L., Ibid , 9 , 198 (1937). ( 2 8 ) Siederl, J . B., and Xiederl, Y,, ”Micromethods of Quantitative I
\----,
(1) Agassi, E. J., Parks, T. 11..:ind Brooks, E’. R.. . ~ - I L .C’HEJI., 23, (1951). (2) Alicino, J. F., Zbid., 20, 85 (1948). (3) =Im. Soc. Testing Materials. Philadelphia, “Book of .\.d.T..\I, Standards,” Part 5 , Method D 271-48, 1949.
Organic Analysis,” New York, ,John Wiley h Sons, 1942. (29) Ogg, C. L., Willits, C. O., and Cooper. F.J., ds.\r..CHEM.,20, 83 (1948). (30) Parr, 9. TT~,J . Ind. E u g . Chcm., 11, 230 (1919). (31) Peabody. W,A., and Fisher, R. S.,ISD.Esc. CHEX.,ASAL.ED., 10, 651 (1938). (32) Pregl, F., “Quantitative Organic Microanalysis.” Philadelphia, Blakiston’s Son & Co., 1930. 133) Schroeder. W. C.. IND. ENG.CHEM.. -\N.LL. ED..5. 403 (19331. (34) Sheen, R. T., andKahler. H. L.. Zbid., 8, 127 (1936). (36) Ibid.,10, 206 (1938). 1.36) Sheen, K.T.. Kahler. H. L.. and Cline, D. C., Ihid., 9, 69 (1937). ( 3 7 ) Sowa, E’. .J., -1rcadi. Y.(2.. and Xieuwland. .J. A , , I b i d . , 8, 49 (1936). ( 3 8 ) Steyermark. All,Bass. E.. and Littnian, B., -IN.%L. C H E Y . . 20, 5 8 i (1948). (39) Stragalid. G. L., and Safford, H. K., Ibid., 21, 625 (1949). (40) Sundberg, 0. E.. and Royer. G . L., I s n . Esti. (’HEM.. . i n . a ~ED., . 18, 719 (1946). (41) Ter JIeulen, H., and Heslinga, J.. “ X e u c Methoden der organischcheniischen Analyse.” Leipzig, Akademische Verlagsgesellschaft, 1927. (42) Wieseiiherger, E., Mikroclumie, 29, 73 (1941). E s c . (?HEX., ;ISAL. ED., (43) IYilson, C . T..and Kemper. W.A , . IND. 10,418 (1938).
(4) .\m, Soc. Testing J1ateri:tls. Philadelphia, “Standards on Petlo-
RECLIVED Dxernber 11, 1950.
Fuel oil
D 129.44
2 42 2 44 2.41 2.42
Cy.5tine (Bureau of Standards) Sulfur (U.S.P.)
Theory
26.i
26 G
Theory
Over 9 9 . 5
100.0 99 2 49.6
accuricy. .4 single determination requires less than 1 hour of total elapsed time, 20 to 30 minutes of IT-hich are operator time. In routine use about sixteen determin:ttions per operator per day might he expected. LITER.iTITRE CITED
Determination of Sulfur and Chlorine in Organic Materials Reduced Scale Oxygen Bomb ELlGIO J. AGAZZI, THO\I IS 11. P4RKS1, *\D FRANCIS R. BROOKS, Shell Deuelopment Co., Emerycille, Calij.
T
H E sulfur or chlorine content of organic mateiials is generally determined in microanalysis by combustion methods such as the Sundberg and Roper (6) modification of the method of Grote and Krekeler ( 3 ) . These methods are widely applicable and generally satisfactory. However, in order to increase their sensitivity for materials t h a t have a low sulfur or chlorine content, the sample size must be increased proportionally. Proper quartztube combustion of large (25 to 50 mg.) samples is in many cases time-consuming and requires considerable care. Present address, Stanford Research Institute, Stanford, Calif.
I t was believed that utilization of a n oxygen bomb for the combustion of such samples might be advantageous, inasmuch as the combustion, which is carried out in a great excess of oxygen under pressure, requires very little operator time and attention. Sulfur and chlorine are determined using a n oxygen bomb by standard methods of the Bmerican Society for Testing Materials ( 1 , 2). However, the standard Parr bomb employed has a capacity of at least 300 ml., and washing the products of combustion from the bomb requires 300 to 400 ml. of water, which makes evaporation to a volume suitable for the determination of small amounts of
ANALYTICAL CHEMISTRY
1012
In the d e t e r m i n a t i o n of sulfur a n d chlorine in w g a n i c substances, t h e oxygen b o m b methods (ASTM D 129 a n d D 808) have proved very useful, particularly for materials w n t a i n i n g metallic w n s t i t u e n t s . A m i n i a t u r e oxygen bomb h a s been developed, in w o p e r a t i o n w i t h the Parr Instrument Co., to provide a m e a n s for the vapid combustion of small samples. The h m b has heen applied, with good S U E ~ ~ S Sto, the analysis of 5- to 150-mg. samples of a n u m b e r of materials, using existing procedures for the determination of sulfate a n d chloride. A significant saving in w m b u s t i o n t i m e is achieved, w m p a r e d to other evmbualion methods, when samples larger than 25 mg. are employed.
sulfate 01' chluride 1~ rather lengthy step. It appeared that this objection could be removed by the use of a smaller homh and, 8.8 smaller bombs were not commercially available, arrangements were made with the Psrr Instrument Co., Moline, Ill., for t,he design and construction of a bomb of approximately 50-ml. capacity. Although it was realized that the reduced scale bomb would be most useful for analysis of materials of low sulfur or eblorine content, a number of organic compounds containing larger propurtions of these elements were also analyned in order to test the applicability of the method to such materials. The bomb combustion techniques employed were modifications of existing ASTM procedures. The sulfate ion content of the bomb washings was
tweon t h i head and body by com&e&on of a ruKber &ne. D~~
~
To ie-
,~ ~
to one side of the I-ml. plaiinum sample cup in order t.o avoid fusion of the coil during ignition of the sample. For igniting the sample, sufficient current is passed through the wire to cause the platinum to glow without melting. The bomb is provided with an adapter line, complete with a pressure gage and the proorr fib tings, for conneoting thc bomb t,o m oxygen cylinder. PROCEDURE
Sulfur. Insert between loops of tKe platinum coil a piece of aotton or nylon thread of such length that one end will extend into the sample cup. Place about 2 ml. of 1%sodium carbonate in the bomb, wetting the walls and head as thoroughly possible. Introduce sufficient sample into the cup to give 5 to 10 mg. of barium sulfate, if possible, Ihut do not use more than 150 mg. of sample. .4dd a sulfur-free nonvolatile diluent, if necessary, until the weight of sample plus dilurnt is 100 to 150 mg. Homogenize the mixture by stirring with it piece of latinum wire; allow the wire to remain in the cup. If the sam$e is a solid, dissolve i t in a suitable solvent before adding dilucnt; if the sample does nut dissolve readily, mix it intimatrly wit,h the dilueut. Place the sample cup in position, dip the end of the thread into the sample, and assemble the bomh. Admit. oxygen slowly until H pressure of 40 ntmospheirs is rearhrd. Immerm the bomh in
Table 1. S u l f u r C o n t e n t of Organic Materials (By reduced 8 0 ~ 1 8oxygen bomh method) % . P'".
sample
F i g u r e 1. Parr Reduced Oxygen B o m b
Scale
determined gravimetrically as barium sulfate sud the chloride ion content wa8 determined by amperometric titration with silver ion (4). A promising rapid procedure for volumetxic determination of the sulfate is described by Siegfriedt, Wiberley, and Moore (6). APPARATUS
The assembld oxygen hamb is shown in Figure 1 and the component parts are s h o w in Figure 2.
Wt. Of 8am~Ie.M g .
Sulfur. % Present Found 0.00 0.01 0.01
White Oil
100
White oil plus n-amyl disulfide
100
1.47
1.44 1.45 1.60 1.47
Diesel fuel
40
1.02'
1.04
Lubricating oil
40
2.48'
2.56
1.08
Oil sample A (6.9% cas03
40
3.09b
8.02
Oilssmple B (8.7% Ba)
40
3.436
3.27
Oilsample C (4.6% Be.; 0.5% P)
40
4.14b
1.m
Oilssmple D (8.7%Ba: 1% PI
40
5.446
High-sulfur oil
14
10.3.
10.4 10.4 9.8 10.1
3-Sulfolene (butadiene rulfone)
7
27.1
26.9
10
18.7
18.3 18.4
p-Toluene sulfonylamide
5.38
26.3
A n d w e d according to A S T N inlethod (I,Appendix VII, November 1948). b Analyzed hy ASTX Method D 1 3 19.
V O L U M E 23. NO. 1. I U L Y 1 9 5 1
Figure 2.
Cnmpoment P a r t s of Oxygen Bomb
oold distilled water and ignite the sample. After irnniersiou For a t least 10 minutes, release the pressure (slowly, to avoid loss of liquid from the bomb by splashing; this operation should require a t least 1 minute). Open the bomb, and if unburned sample or sooty deposits are found, discard the determination. Rinse the interior, includin the sample cup, with a fine jet of distilled water, collecting &washings (about 100ml.)in a 150-ml. beaker. To remove any precipitate From the sample cup, place it in a 20ml. beaker, and add 0.5 ml. of concentrated hydrochloric acid and sufficient water to cover the cup. Heat just below boiling for 3 to 4 minutes. Transfer the contents of the beaker and sample cup to the 15aml. beaker, d d 1 ml. of saturated bromine water to oxidize all sulFur to sulfate, and evaporate to about 5 ml. (this requires approximately 40 minutes). Determine the sulfate ion content OF t,he solution by a microgravimetric procedure. After each analysis rinse the bomb thoroughly with water. Chlorine. To prevent corrosion of the bomb, coat the interior with a viscous 4% gelatin solution containing2.5%sodiumcarbonate. Ignite the sample as desoribed above, using sufficient sample to give 0.5 to 2.0 mg. of chlorine, if possible. Rinse the bomb and sample cup with water and add a crystal of sodium sulfite to ensure complete reduction of chlorine to chloride. Evaporate the alkaline solution to approximately 20 ml. and determine the chloride ion oontent, by mnperometrir t,itrxtion with 0.01 N sililaw nitvnte solution. RESULTS mn niscussioN
A number of organic materials of known sulfur content were analyzed, with the results shown in Table I. A comparison ai the values obtained by this method with those obtained by oalculation or by established macromethods shows good agreement; results obtained with the bomb tended to he slightly low. When a sample containing little or no sulfur was analyzed immediately after the analysis of a sample high in sulfur, high reRults were invariably obtained. The last traces of sulfate could be removed by rinsing the bomb thoroughly in a large volume of distilled water after the analysis of high-sulfur samples. Results obtained for various chlorine-containing materials are shown in Table 11. As in the case of the sulfur analyses, good agreement was obtained between the determined and known values. The tendency for the bomb results to be slightly low was again observed. Occasionally there was evidence of corrosion in the bomb, generally a t the base of t,he terminals, which could be the cause of the low results in these cases. The use of an alkaline gelatin mlution to coat the interior of the bomb was generally more effective in preventing corrosion than the ASTM expedient of maintaining the chlorine content of the mixture in the sample cup a t a low level by suitable choice of weight of sample and diluent. An aqueous alkaline solution is less satisfactory for this purpose, because it does not coat the bomb walls completely. In the combustion of pchloroacetanilide and Zchlorobenzoic acid samples, a small but significant amount of chlorine was found in the gas released from the bomb after combustion. In order to eliminate this source of error, the bomb gas was passed through dilute sodium carbonate solution, which in turn was analyzed for
1013 chloride, and the amount found was added to the results for these semples. Because these results would otherwise have been low, t& precautionary step is recommended far combustion of materials high (greater thair 5%) in chlorine. To aid in the combustion of samples, p r t i c u lady when only FL small amount of sample was used, a high boiling diluent was added. The total weight of diluent plus sample recommended u'a8 arbitrarily obtained by reducing the amount specified in the ASTM methods (0.6 to 0.8 gram) in the ratio of the smell to large bomb volumes. The diluent employed muat be readily combustible and must also have a sufficiently high boilin8 paint to prevent errors in weighing -~ due to lo;& by vapkiaation. Because it is believed that best combustion is achieved with homogeneous mixtures, solids were dissolved in a small immunt tiuit,ablesolvent prior to the addition of diluent. Although best results are obtained by solution of solid samples, solids a-hich m e insoluble can generally he burned by miring thoroughly wit,h R diluent.
Chlorine C o n t e n t of Organic *Materials
'Vahle 11.
(By reduced acsle oxygen bomb method)
h prox. wt. of Lmple, Mg. Whiteoil
50
Simulated high additive oil Chlorinated wax in white oil
Chlorine, % Preeent 0.00
Found 0.02
0.00 0.01 1.73 1.74
45
1.87'
A
60
0.49
0.47
R
50 35
0.78 3.25 22.4
0.48
!&Chlorohen~.r~ir acid (NBS 144)
6
0.81 3.30 22.6
p-Chloruncctanilide
6
20.9
20.R
Uliiurinrted wax S-Bensylimthiourea hydroohlaride
9
17.3
6
17.5
17.1 17.1 17.3
c
21.96 22.4
h
20.6
Analyzed by l S T M Method D 8CR-49T. Il,preoiable aorrosion in bomb.
For the analyais of 5- to Wmg. samples the method offers little or no saving of operator time over a conventional combustion method such as that of Grote and Krekeler (3,6). However, it appears to he useful for testing samples when the amount available is too small to permit u ~ of e a macromethod, and when the sulfur or chlorine content is so low it^ to require s sample of 25 to 50 mg. LITERATURE CITED (1) Am. SOC. Testing Materials, Philadelphia, Pa., Committee D-2.
"A.S.T.M. Standards on Petroleum Products and Lubricants," B. 770,1948. Ibid.. p. 990.
Grote, W., and Krekeler. H.. Angew. Chem., 46, 103 (1933). Laitinen, H. A., Jennings, W. P., and Parks. T. D., IND.ENO.. CHEY.,ANAL.ED.,18,355 (1946). Siegfriedt, R. K., Wiberley, J . S.. nd Moore, R. W.. ANAL. CHEM.,23, 1008 (1951). D. ENB.CHEM.. ANAL.Rn., Sundberg. 0. E., and Royer. G . R.. INI 18, i19 (1946). H ~ c m v mNorember 13.1950.
