pected, the sum of the following reactions : Na3AlFa
+ 2H20 2NaF
2NaF
+
+ 4HF + NaA102
+ l l A 1 ~ 0 3+ HzO
-+
Na20.11Al203
+ 2HF
(5) (6)
to yield:
+ +
+
sodium fluoride reacted to form @alumina, i t is suspected t h a t other reactions similar to Equation 6 took place to form compounds of the type, Na20.zA1203,where z was intermediate between 1 and 11 and the value of z was dependent upon the ratio of a-alumina to cryolite in the original mix.
NaaAIFs 3H20 11Al~O3+ 6HF Naz0.11A120~ NaA102 (7)
LITERATURE CITED
stoichiometry would require that the mole ratio of a-alumina t o cryolite in the charge be at least 11 t o 1. I n practice, a mole ratio of approximately 6 to 1 (weight ratio 3 to 1) gave a n essentially complete recovery of fluoride as hydrofluoric acid. Thus, while some of the
(1) Banks, C. V., Burke, K. E., 0’ Laughlin, J. W., Anal. Chim. Acta 19, 239 (1958). (2) Brownlee, K. A., “Industrial Experimentation,” 4th ed., Chap. I11 and IV, Chemical Publishing Co., New York, 1952. (3) Chilton, J. M., Horton, A . D., AXAL. CHEM.27, 842 (1955).
+
(4) Gahler, A. R., Porter, G., Ibid., 2 9 ,
296 (1957). (5) Griotheim. Kai. “Contribution to the The&y of the Aluminium Electrolysis,” 22, I Kommisjon Hos F. Bruns Bokandel, Trondheim, 1956. (6) HafS, L. V., Butler, C. P., Bisso, J. D., ANAL.CHEM.30, 984 (1958). (7) Hibbits, J. O., Ibid., 29, 1760 (1957). (8) Marstilles, C. M., Research Laboratory, Aluminum Co. of America, private communication. (9) Menis, O., Powell, R. H., ANAL. CHEM.30, 1546 (1958). (10) Susano, D. D., White, J. C., Lee, J. E., Ibid., 27, 453 (1955). (11) Warf, J.C., Cline, W. D., Tevebaugh, R. D., Zbid.,26, 342 (1954). (12) Willard, H. H., Winter, 0. B., IND. ENG.CHEM.,ANAL.ED. 5 , 7 (1933).
.,
E.
RECEIVED for review March 17, 1959. Accepted August 17, 1959.
Evaluation of a Commercial Alkyl Aryl Sulfonate Detergent as a Column Packing for Gas Chromatography D. H. DESTY and C. L.
A. HARBOURN
Petroleum Division, Research Centre, The British Petroleum Co., ltd., Sunbury-on-Thames, Middlesex, England
,A solid anionic household detergent containing about 17% of an alkyl aryl sulfonate has been recommended as a general-purpose packing for gas chromatography. The effects of flow rate and particle size on column efficiency have been studied at an operating temperature of 134” C. with samples having a wide range of retention volumes. Comparative data are also given at other operating temperatures. The optimum conditions for specific separations are discussed. The separation behavior of the packing has been studied and retention volume data for a large number of volatile materials, mainly hydrocarbons and sulfur compounds, are given for an operating temperature of 245” C. This packing has a wide field of application especially for analytical purposes at high operating temperatures where the ability to construct long columns of high efficiency having a low pressure drop is particularly valuable.
A
a variety of stationary phase liquids have been employed in gas-liquid chromatography, kieselguhr or powders obtained from diatomaceous earth firebrick have been used almost exclusiyely.as supports. Gohlke and McLafferty ( 2 ) demonstrated that a commercial, household, solid detergent made a good general-purpose column LTHOUGH
packing combining the functions of both stationary phase and support. Little detailed information has, however, been published on its performance. The spray-drying technique used in the preparation of this type of detergent appears t o have a wide application in the preparation of column packings for gas chromatography. The characteristics of a commercial alkyl aryl sulfonate detergent similar to that employed by Gohlke have, therefore, been investigated particularly with respect to the factors determining column efficiency. I n addition, the nature of the separation produced with hydrocarbons and sulfur compounds has been examined. APPARATUS
The chromatographic instruments employed in this work are of two different types. The first, with which most of the work was carried out, has as detector the gas density balance devised by A. J. P. Martin. Two models were used, one similar to that originally described by James and Martin ( 6 ) , and the other a modified design for use a t high temperatures. An improved recording system comprising a Leeds & Northrup DC microvolt amplifier feeding a 10-mv. high speed (1 second full scale) potentiometric recorder has been incorporated in both instruments. The second, which was used only for the determination of the relative reten-
Table I. Sieve Analysis and Water Content
Mesh Size (BSS) > 18 18-30 44-72‘ 72-100 18- and 18-mesh has the lowest ratio of pressure drop to efficiency. A column packed with this material could achieve about 70,000 theoretical plates with a pressure drop about 20 p.s.i. The column would be long (about 150 to 200 meters) and the detector would have to be considerably more sensitive than those currently employed. The new forms of detector, based on ionization in the gas phase recently described (4, 10, IZ), should however, easily respond to the small concentrations involved, even with the very long elution time (ca. 100 hours). The choice of a suitable temperature for a particular separation is difficult, because a number of aspects-time for analysis, efficiency required, and separation factor (7)-are involved. It can be seen (Figures 4 and 6) that raising the temperature of operation increases the efficiency obtained but reduces the separation factor. The resolution of nparaffins a t any particular teinperature nil1 be controlled by these tn o opposing factors. Calculation of the resolution
X J A M E S AND M A R T I N (PARAFFIN C
LIQUIDS)
0 DETERGENT
~-
2 c
- ~-
A
AP EZON
2
- &LKANES D - ALKYLENZENES
GREASE L T-DETERGENT
0
c 0
E
'
I O -
Y3
$
1
3
CYCLOALKANES
d
fi-
ALKYLNAPHTHALENES
5
PHENYLBENZLNES
6
CONDENSED
I
AROMATICS
1
z
E
o
2 1 a Y
f
l
I
l
