809
V O L U M E 22, NO. 6, J U N E 1 9 5 0 Table I. Monomer
Analysis of Monomers % Monomer
Mole BrdMole Monomer 0.885
Isobutyl acrylate Ethyl methaorylate Allyl butyrate Diethylene gl col bis(al1ylcargonite)
0,989 0.998
98.5 98.9 99.8
1.948
97.4
Table 11. Analysis of Synthetic Monomer-Polymer Mixtures A. B. C. D.
% Monomer
Compound Methyl methacrylate Isobutyl acrylate Polymer methyl methacrylate Polymer isobutyl acrylate
98.7 98.5 3.1 2.6
% Monomer Mixtures
50% B
Analysis
Theory
74.5 49.7 74.8 49.6
74.8 50.9
mean square error for ten independent analyses of the diethylene glycol-bis(ally1carbonata) sample was +0.287%. Synthetic monomer-polymer mixtures were prepared to test the analytical procedure. The polymers were prepared according to Cohen et d.( 4 )from sirupy polymerized methyl methacrylate and isobutyl acrylate. The analyses of these polymers, the monomers, and their synthetic mixtures are given in Table 11. Figures 6 and 7 depict the rate of several bulk polymerizations carried out a t 60 C. using 0.015 mole fraction of benzoyl peroxide as the polymerization agent. The unsaturation, expressed as per cent monomer (see Formula I), is plotted against time. ACKNOWLEDGMENT
The authors wish to express their thanks to the U. S. Navy Bureau of Aeronautics for financial assistance and permission to publish the work done on this project.
74.5 50.5
LITERATURE CITED
(1) Bartlett, P. D., and Altschul, R., J . Am. Chem. Soc., 67, 815
solution for excess bromine. This absorption serves to enhance the addition reaction by concentrating bromine in the polymer. The error of the analysis varies up to about 2%, depending upon the size of the sample, the aliquot portion taken, and the normality of the solutions employed. EXPERIMENTAL RESULTS
Table I gives analytical data for commercial monomers which were vacuum distilled a t 1-mm. pressure under a nitrogen atmosphere and analyzed for unsaturation immediately after distillation. These analyses were all carried out in triplicate. The root
(1945). (2) Boeeeken, J., and Gelber, E., Rec. tras. chin., 46, 158 (1927). (3) Ibid., 48, 377 (1929). (4) Cohen, S. G., Oatberg, B. E., Sparrow, D. B.,and Blout, E. R., J . Polymer Sci., 3, 264-82 (1948). (5) Davis, H. S., Crandall, G. S., and Higbie, W. E., IND. ENG. CHEX.,ANAL.ED.,3, 108 (1931). (5) Evans, A. G., and Tyrrall, E., J . Polymer Sci., 2, 387 (1947).
(7) Kemp, A. R., and Mueller, G. 9.. IND.ENO.CHEM.,ANAL.ED.,6, 52 (1934).
(8) Lucas, H. J., and Preasman, D., Ibid., 10, 140 (1938). (9) Mulliken, S. P., and Wakeman, R. L., Ibid., 7 , 5 9 (1935). (10) Robertson, P. W., Clare, N. T., McNaught, K. J., and Paul, G. W., J . Chem. Soc., 1937, 335. RECEIVED November 20,1948.
Streak Reagents for Chromatography A. L. LEROSEN, P. H. MONAGHAN, C. A. RIVET, E. D. SMITH, AND H. A. SUTER Louisiana State University, Baton Rouge, La. A number of streak reagents, used in detecting zones of colorless substances on the chromatographic column, have been studied in regard to their usefulness in the detection of certain compounds. These reagents are all sensitive at concentrations of 0.01 molar. Several new streak reagents have been developed.
A
NUMBER of methods have been developed for the detection
of zones of colorless substances on a chromatographic column. Three of the most useful techniques are the detection of a zone by its fluorescence in ultraviolet light (4, 8),the detection by the formation of a dark zone on a fluorescent adsorbent (I,6), and the detection by the use of streak reagents (9). Streak reagents are effective in concentration ranges where methods, such as refractive index changes, are often insensitive or difficult to apply, and are more broadly applicable than the other two methods mentioned. As a by-product of some work in this laboratory on the specificity of adsorbents the authors have acquired a considerable amount of information on the usefulness of these reagents on seven different adsorbents in detecting. the following compounds: aromatic and aliphatic amines, alcohols, phenols, ketones, acids, aliphatic and aromatic nitro compounds, unsaturated hydrocarbons, aromatic compounds, and carbon disulfide. They present this information in the hope that it will be useful to workers who need to detect similar compounds. Table I includes a summary of some streak reagents already reported. The resulta of the authors' work are summarized in Table 11; data are given here for specific compounds on seven
adsorbents and for two solvents, benzene and petroleum ether (60" to 70" C. boiling point). The testa in Table I1 were all satisfactory a t 0.01 M concentration, which waa selected because many tests are unsatisfactory at greater dilution. In all cases the initial volume of solution waa urz ml. (r = chromatographic tube radius). In some instances, where no suitable streak reagent was found, the application of other methods hrts been indicated. In general, it is desirable to have several streak reagents for a given type of compound, because it is not always possible to use a given reagent on all adsorbents-for example, acidic reagents are usually unsatisfactory on the carbonates. Spot test reactions and color reactions in general may be unsuitable for use on certain adsorbents or may require certain modifications before use, because of the effect of the adsorbent and the fact that very strong colors are required, owing to the thin film of liquid or of adsorbent surface available for color detection. Some of the reagents used are new; others are adaptations of already existing tests as indicated by the literature references. Directions are included for preparation of these reagents. The reliability of these testa was checked by employing other detection methods to establish the presence of the substance sought in the zone detected.
ANALYTICAL CHEMISTRY
810 Table I.
Streak Reagents Found in Literature
Reagent Zone Color Compounds Detected Bensidine or na hthylAqueous s o h . of diasonium Green or red amine, naphtfols salt Lead peroxide in 30% ace- Blue or green Benaidine or naphthylamine tic acid Many oxidizable comKMnO4 Green pounds Aldehydes Schiff'8 reagent Violet Nickel sulfate Dimethylglyoxime Red Vitamin A SbClr in chloroform Blue 1% ceric sulfate in 85% Brown, blue, Urea, urethanes, and sulfuric acid or red related compounds 0.25% vanadium pentoxide Brown blue, Urea, urethanes, nitro or reh in concd. H&Or compounds and their derivitives Same as previous test 17 KICrrOi in concd. HI- Brown and io4 red Nitro compounds 6 N sodium hydroxide and Colored 50% potassium hydroxide Nitrates, N-nitroso, a. 0.25% diphenyl- Blue nitramine compounds amine in concd. sulfuric acid b. 6 N sodium hydroxide" Diphenylamine and re1 % sodium +trite in ooncd. Blue lated cornpounds aulfurio acid R D X , nitramines, and Weak pink Griess test related compounds a. 6 N sodium hydroxide b. Aqueous soln. containing 30% acetic a$d. 0.5% sulfanllic acid, 0.15% anaphthylamine'
Lit. Ref.
Lit. Compounds Detected Ref. RDXb, nitramines, re- (7) lated compounds
Reagent Zone Color Benzene-Franchimont test" Pink a. Zn dust b. Benzene e. Griess solution Schryver testo Red a. 19 phenylhydrazine k g h l o r i d e in
(0) (9)
o)
taspium femcyanide Saturated soln. of a-naphthxlamine in concd. 1
(7)
(7)
Pink
N-Nitroso compounds
(7)
Colored
4-Nitroaniline
(7)
Colored
Several types of com- (7) pounds Nitrosonitro ( 7) compounds Some compounds Pyridine
5 % aq. soln. of po-
b.
("
(8, 0 )
RDXb, and related compounds, formaldehyde
Il",
Satd. a soln. of calcium% ochlorite b. 6NNaOf?c Concd. HISO, n.
(7) (7)
Concd. HISO44 b. 6 N N a O H Concd. HC1 Vongerichten's testc a. Satd. s o h . of 2.4-dinitrochlorobenzene in alcohol b. 6 N N a O H
Colored
a.
(7) \ ,
(7)
(7)
Colored Pink-orange
a Order listed indicates order in which reagents should he used. Streaks should be placed one upon the other. b Hexahydro-l,3,5-trinitro-s-triazine (cyclonite). Order listed indicates order in which reagents should be used. Streaks should be placed adjacent to one another on the column but not touching.
(7)
PREPARATION AND USE OF REAGENTS
This gives a yellow zone on a colorless column. It has been used only for nitrobenzene. ~ Reagent, ~ 4. Alcoholic Potassium Hydroxide and ~ Directions for the preparation of Nessler's reagent are given in all handbooks; the standard solution was used. The alcoholic potassium hydroxide is composed of equal parts of ethyl alcohol and 6 N p o h s i u m hydroxide. The column is first streaked with the potwsium hydroxide and then overstreaked with Nessler's solution; carbon disulfide forms a yellow zone. 5. BDH Universal Indicator. This indicator can be used for some amines and acids. The color change is red for acids and green for bases. 6. Bromine inCarbonTetrachloride. A5%solutionof bromine in carbon tetrachloride is the reagent used. It is useful for some ammea. A colored section of the column indicates the zone.
In the following section are given the preparation and method of application of each of the streak reagents listed in Table 11. For convenience the tests are listed numerically.
1. Alkaline Permanganate (6,9). This reagent is a 0.0075 M otassium permanganate solution in 0.25 M sodium hydroxide. !'he zone color is green and the blank column is purple. 2. Diazonium Reagent. This reagent is 1% aqueous solution of -nitrobenzene diazonium fluoroborate. The zone is yellow to refon a colorless column. 3. Zinc Dust and Alcoholic Sodium Hydroxide. A pinch of zinc dust is added to a mixture of 1 ml. of 6 N sodium hydroxide and 1 ml. of ethyl alcohol and the mixture is heated just to boiling. ~~
Table 11. Tabulated Streak Tests and Other Detection Methods Used to Locate Adsorbate Zones CaCOa Speoial Filtrol No, Adsorptive Baa P.E.b 1 1 1 1 1 2 1 3 1,2 1, 2, 17 ... 4 1 1 5 1, 2, 17 6 1, 2 1, 2, 17 Ethylaniline ... 7 1, 2, 17 Diethylaniline 8 1,2,'17 1, 2,17 Dimethylaniline 9 17 Diphenylamine 10 17" 17 Triphenylamine 11 1 1 Methanol I2 1 1 13 Ethyl alcohol !, 2 Phenol 14 1,2 1 I Acetone 15 1 1 Anisole 16 18 1 Chlorobenzene 17 1 1 Acetic acid 18 1, 18 18 Benzoic acid 19 1 1 Nitromethane 20 3 3 Nitrobenzene 21 18 22 Benzene 19 Carbon disulfide 4 23 6. a, Benaene. 7 b Petroleum ether. 8: 1. KMnO4. 9. 2. Diazonium. 10. 3. Zn dust alc. NaOH. 11. 4. Methanoic KOH and Nessler's. 12. 5 . B D H Universal indicator.
...
+
Silicic Acid Bz P.E. 1 1 2 1 2
...
1
...
...
8
... 1 1,9,16
... ...
8 8 ?;
9
id, '13
1, 2 1,2 1,2 1, 2 1, 2 1,2 15 15 1 1, 9,16
...
18 5 5 1 3
...
Florisil Bz P.E. 1 1 2, 1 1 1 1, 6 1, 2 1, 6 1, 6 1 1,6 6
i,
1 1,2 1, 9, 16 1
1 1 3
...
...
...
1 1. 6 1, 6 1. 6 1, 6
6 6
MgO Bz P.E. 1 1 2 1,2 1 1.2 1,2 1, 2 1, 2 1,2 6
1 1 1,2 9,16 1
1 1 1, 2 1 1
1 1 1 3
1 1 1 3
... ...
... ...
13 4 4 13 Brz in CCI4. Nickel dimeth 1 glyoxime. Iodide-starch-xrornate. Negative Nessler's teat. Azide-atarch, iodide. Schiff's and Nesaler's. Copper sulfate followed by bromine fumes.
BZ 1 1 5
...
1, 5 1 . I .
I
...
1 1 1, 2 1 1 1
. . . 5. . .
..
1 3 17 4
1 3
P.E. 1 1 5 1
5
1, 18 1 1 1 1 6, 18 1
1 1
..
..
1 1 1 12
2
1 1 1 1
2
... ...
...
.. 1
CaHPO4.2Ha0
P.E. Bz 1 1 1 1 11,12 2 6. 12 .. 1, 12 .. 1 2 6
1
1 18 18
1
...
...
...
14
i
1 1
..
1
3
..
P.E. 1 1 2 2 1 2 2 1 2 2, 14 2, 14 1 1 2
1 18 18
...
...
1 3 18 19
4 4 13 Formalin and plumbite. Special Filtrol suspension. CSr, 19% KOH, and Nes?ler:s. 2,4-Dinitrophenylhydrazinein HCI. Vimsl. Olfactory. Speotroscopic.
4
13. 14. 15. 16. 17. 18. 19.
Bz 1 1 11,12
1 1
1 3, 18 18
4
Ca(0H)r
~
l
811
V O L U M E 22, NO. 6, J U N E 1 9 5 0 7. Nickel Dimethylglyoxime Reagent (2). A 0.1 solution of nickel sulfate is saturated with dimethylglyoxime and the supernatant liquid is used as the streak reagent. It is useful for very basic substances. The zone is red on a colorless column. 8. Iodide-Starch-Bromate Reagent. The reagent is prepared by mixing equal volumes of 1% potassium bromate, 1% potassium iodide, and 5% starch solutions just before using. It is useful as test for acids. A dark blue zone is a positive indication. 9. Negative Nessler’s Test. Nessler’s reagent is streaked on the column and then overstreaked with 1 M ammonia. The inhibition of the orange color due to the reaction of the Nessler’s reagent and the ammonia indicates a zone of acetone or nitromethane. 10. Azide-Starch-Iodide Reagent (2). This is prepared by mixing equal volumes of saturated solution of iodine in 1% p o t s sium iodide and a solution of 10% sodium azide in 1% starch. A bleaching of the blue color indicates a zone of carbon disulfide. 11. SchB’s and Nessler’s Reagent. The column is first streaked with Schiff’s reagent and after 2 minutes is overstreaked with Nessler’s reagent. A blue zone indicates some aliphatic amines. 12. Cupric Sulfate and Bromine Fumes. The column is streaked with the 0.1 M cupric sulfate solution, then exposed to fumes from a dilute solution of bromine in carbon tetrachloride passed over the column in a medicine dropper. The blank portions of the column alon the cupric sulfate streak turn brown while the zone remains byue. This test is useful for di- and triarylaniines. 13. Formaldehyde and Plumbite Test (2). The column is first streaked with a 40% solution of formaldehyde and followed by a streak of 0.1 M sodium plumbite; a brown zone indicates carbon disulfide. 14. Special Filtrol. A suspension of special Filtrol in petroleum ether or benzene is prepared. This suspension is streaked on the column so that there is a streak of the special Filtrol powder deposited. This powder will form a green or blue zone with many amines.
15. Nessler’s-Potassium Hydroxide-Carbon Disulfide Reagent. The column is streaked with carbon disulfide and overstreaked with 10% potassium hydroxide, which in turn is overstreaked with Nessler’s reagent. The formation of a vellow zone indicates an alcohol. 16. 2,4-Dinitrophenylhydrazinein Hydrochloric Acid (3). A saturated solution of 2,4dinitrophenylhydrazine in 2 M hydrochloric acid gives a strong yellow zone on a pale yellow background with ketones and aldehydes. On overstreaking with 6 M sodium hydroxide a transient dark color develops. The following reagents have not been found in the literature and are apparently new in their application as streak tests: 2, 3, 4,8, 9,11, 12, 14, 15, and 16. LITERATURE CITED
Brockmann, H., and Volpers, F., Ber;, 80, 77 (1947). Feigl, F., “Spot Tests,” 3rd ed., New York, Elsevier Publishing Co., 1946. Iddles, H. A., Low, A. W., Rosen, B. D., and Hart, R. I., IND. ENG.CHEM.,ANAL.ED., 11, 102 (1939). Karrer, P.,and Schopp, K., Helu. Chim. Acta, 17, 693 (1943). Sease, G. W., J. Am. Chem. SOC., 69, 2242 (1947); 70, 3630 (1948).
Strain, H. H.,“Chromatographic Adsorption Analysis,” New York, Interscience Publishers, 1942. Trueblood, K. N., Sohroeder, W., and co-workers, OSRD Rept. 5952 (1946).
Winterstein, A., and Schon, K., 2. physiol. Chem., 230, 139 (1934).
Zechmeister, L., and Cholnoky, L.,“Principles and Practices of Chromatography,” 2nd ed., New York, John Wiley & Sons, 1944. RECEIVEDMarch 9. 1949. Presented a t the Southwest Regional Meeting of the AMERICANCHEMICAL SOCIETY,Shreveport, La., December 1948. Work done under Contract N7onr-356, T.O. I V between the Office of Naval Research and Louisiana State University.
Characterization of Some Chromatographic Adsorbents PATRICK H. MONAGHAN, HANS A. SUTER, AND ARTHUR L. LEROSEN Louisiana State University, Baton Rouge, La. Data a r e presented here for the characterization of a number of chromatographic adsorbents. The relation between T,, and Yois derived and confirmed by experimental data.
T
HE work reported here is part of a program of study of the specificity of chromatographic adsorbents. It was necessary to know the characteristics of the common adsorbents in order to select those suitable for use. AE a by-product of this investigation some interesting relations have been shown between the adsorbent and its properties. The methods used are described elsewhere ( 8 ) ; they consisted essentially of determining for each adsorbent the characteristic and measuring adsorption affinity. Other values of V,, and TKO, terms such as k and K could be calculated from these data.
A
= driving pressure, mm. mercury
a
= column interstitial volume, ml. per mm. = viscosity of solvent, centipoises = column length, cm. = a packing measure defhed as the ratio of the length of packed column required to hold a unit volume of solvent to the length of unpacked tube required to contain the same volume of solvent = distance of a point on an adsorptive zone from the top of the column (usually the leadmg or trailing edge of the zone) = distance the front edge of the developing solvent has moved in the packed column, measured from the top of the column = ratio of the movement of an adsorbed zone to the movement of the solvent defhed mathematically as dz/dD. The rate for the leading edge is Rz and for the trailing edge is Rt. For this determination the initial volume of solution was i r l ml. of 0.01 M solution ( r is radius of tube used)
?
L
s z
D
DEFINITION OF TERMS
V , = rate of flow of the developing solvent through the chromatographic column measured in mm. per minute a t constant flow. The values given are for columns 75 * 2 mm.’ long packed under vacuum alone. The driving presmre was about 700 mm. of mercury. The vacuum waa supplied by a water pump. The packing is aided only by tapping the glass tube with the stamper until no more settlin is observed T~= o time in second% required for the solvent to penetrate 50 mm. into an initially dry column 75 * 2 mm. long under a driving force of a pressure of about 700 mm. of mercury (the full vacuum supplied by a water pump). I n the present work benzene was used as the solvent = permeability of column in darcys k K = a constant formed by the grou ing of constants ( k A / 760a). This constant is usefur in estimatin the flow rates through other types of column (V, = f?P/rlL)
= cross-sectional area of the column, sq. cm.
P
R
The experimental data are shown in Table I ; blanks indicate that the data were not obtained because of difficulty in measurement. On prewashed columns TSO could not be obtained and in general calculations were not made for k and K . On some adsorbents the o-nitroaniline zone could not be detected because of the dark color of the adsorbent, etc. Attempts to use fluorescent substances for the R determination on these adsorbents were not successful because the fluorescent zone could not be observed.
