Table 11.
Run NO.
8
Recovery of Nonionics from Mixtures with Anionics
Components and Structure Monamid 150D, diethanolaminecoconut fatty acid con- / densate UltrawetE, R SOJNa
3
+
9 10 11
+
G-672, glycerol sorbitan ester, Lathanol, Na lauryl sulfoacetate SarkSterox SK, RS(C2H40)zH, osyl XL100, Na lauroyl sarcosinate Ethofat 142/15, RCOO(CzH40).H,
+
+
12 13
yo
Nonionic Product n Obsd. Theor.
Ash,
97
1.4770
1,4732
0.15
104
1.4686
1.4690
0.05
104
1.4790
1 ,4770
0.40
114
1.4802
1.4732
0.05
105
1,4660
1.4581
0.12
89"
1.4697
1.4698
...
103
1.4911
1.4918
...
103
1.4828
1.4820
...
98
1,4530
1.4520
...
125
1.4710
1.4586
0.20
36
1.5055
...
0.20
97
1.4748
1,4740
...
105
1.4632
1.4631
...
103
1.4560
1.4550
94
1.4682
1.4672
Yield,
Triton X200, S03Na Propylene glycol monoolzate Sulfonate OA5, Na sulfostearic acid Polyoxypropylene mannitol dioleate Polyfon T, N a lignin sulfonate
+
+
%
14 15 16 17
carballylate Sterox CD, RCVOO(C~H~O)~H, Duponol WA, ROSO3Na Brii 30. RIOCJLLOH. Aerosol dT, sulfdsuc6inaie Renex 30, R(OC?Hd),OH, Triton
+
+ +
770, R@OC;Hi)iiO4hr
0
18
Triton 770, R
19
Span 20, sorbitan ester, Hyponate L, petroleum sulfonate Polyethylene glycol 400 monooleate, Stepanol &IS,ROS08Na Pluronic L62, polyoxyethyleneoxypropylene glycol Igepon AC, ?r a lauroyl isethionate G-1165, polyoxyethylene gAucoside
20
21 22
(OC2H4),S04Na
+
+
+
+
ester, Daxad 11, ( SOtNa a
Product not readily soluble in methanol.
jected by itself to the ion exchange procedure. The results (run 18, Table 11) showed that a considerable portion (36%) of the original material was nonionic. This accounted almost exactly for the extra 25Yc of nonionic material obtained in the previous run. The high index of refraction of the nonionic portion accounted for the large deviation in the refractive index of the product from run 17 and indicated the impurity to be unsulfated alkylphenouypolyethoxyethanol-Le., unconverted base material. The poor yield of nonionic in run 13 was found subsequently to be dup to incomplete removal of it from the resin during the washing procedure, because of the unusually low solubility of this particular nonionic in methanol. Run 10, in which a salt of a n acylated amino acid was separated successfully from a nonionic, indicates that the procedure can be used to separate carboxylic acids and their salts from nonionic materials. The elution of the anionic portion from its complex with the ion exchange resin and the separation of nonionics from cationics by batch ion exchange are under investigation at present. LITERATURE CITED
Epton, S. R., Trans. Faraday SOC. 44, 226 (1948). Klevens, H . B., ANAL.CHEM.2 2 , 1141 (1950). Kling, W., Puschel, F., Melliand Teztilber. 15, 21 (1934). Lampert, J. M., J. Colloid Sci. 2, 479 (1947). Van der Hoeve, J. A , Rec. trav. chim. 67,649 (1948). Wijga, P. W. O., Chem. Weekblad 45, 477 (1949). RECEIVED for review October 26. 1956. Accepted June 10, 1957. Meeting-inMiniature, N e w York Section, ACS, March 16, 1956.
Determination of Higher Aliphatic Aldehydes in Presence of Ketones and Fatty Acids L. D. METCALFE and A. A. SCHMITZ Research Division, Armour and Co., Chicago
b The ease with which aliphatic aldehydes are oxidized to fatty acids is the basis of a method for determining higher aliphatic aldehydes in the presence of ketones and fatty acids. The aldehyde is oxidized to fatty acid with a mixture of 370 hydrogen peroxide and standard sodium hydroxide. The amount of standard alkali used in the reaction is a measure 1676 *
ANALYTICAL CHEMISTRY
9, 111.
of the aldehyde.
Any free fatty acid in the aldehyde is titrated separately and a correction is provided.
I
of higher aliphatic aldehydes from fatty acids, it became necessary to determine the aldehydes in the presence of ketones and fatty acids. A number of analytical systems have been devised for deterN THE MANUFACTURE
mining aldehydes in the presence of ketones but none specifically for aliphatic aldehydes of higher molecular weight. Methods include use of bisuihyfite (Zl), dimethylhydrazine (W), droxylamine (6, 6 ) , paper chromatography (18, 19), and a series of oxidizing agents (1, 10, 14-16, $0,272). Blank and Finkelbeiner (2, 3) first proposed oxidation with alkaline hydrogen per-
oxide for formaldehyde. Other authors (4, 7 , 8-16, 17) devised modifications for various aldehydes of low molecular weight. Reviews of various analytical procedures are available (8, 9, IS, 24). It was decided that the ease with which aliphatic aldehydes could be oxidized offered the best solution to the problem of rapid determination in the presence of fatty acids and ketones.
Normally, water is not considered as a medium for quantitative reactions of higher aliphatic chemicals. However, higher aliphatic aldehydes were known to react quantitatively with sodium bisulfite in aqueous media, so it was decided to try to oxidize the aldehydes to fatty acids in an aqueous system of standard alkali and 3y0 hydrogen peroxide a t elevated temperatures. The aldehydes underwent quantitative oxidation rapidly. The low volatility of higher aliphatic aldehydes makes their oxidation a t steam-bath temperatures a much simpler operation than that of the more common low molecular weight aldehydes. The reaction involved is
+
Hz02
+
KOH
A
=
ViNi ~
si
sz
where
VI
ml. of standard potassium hydroxide to titrate acidity V z = ml. of standard hydrochloric acid to back titrate excess alkali B = ml. of standard hydrochloric acid to titrate alkali in blank AT1 = normality of standard potassium hydroxide (0.1N) AT* = normality of standard hydrochloric acid (0.5N) =
Table 1.
The amount of standard alkali used up in the reaction is a measure of the aldehyde. Any free fatty acid in the aldehyde is titrated separately and a correction provided.
&
=
mine acidity grams of sample used to determine aldehyde
Analysis of Purified Higher Aliphatic Aldehydes
70Free
RCOOKf 2HZO
= grams of sample used to deter-
A series of aldehydes (Table I) was prepared and fractionated. These aldehydes were analyzed as soon as they were distilled by a hydroxylamine or bisulfide procedure and by the described oxidation procedure. Up to decanal no difficulties were encountered. Aldehydes of chain length greater than Clz required a slightly modified procedure using 5% hydrogen peroxide and a longer reaction period. The C, and CI8 aldehydes nere never allowed to freeze after distillation because it was found that lower results were always obtained under such conditions. This is probably due to the great tendency of the higher members of the series to form polymers. A number of synthetic mixtures of aldehydes, fatty acids, and ketones were then prepared and analyzed for
Aldehyde, meq. per gram = ( B - V2)S2 - A
--t
Reagents. . .. Aqueous sodium hydroxide, IN. Hydrogen peroxide solution, 3%. Make fresh daily by diluting 30% hydrogen peroxide with distilled water. Standard aaueous hvdrochloric acid. 0.5N. Standard aqueous potassium hydroxide, 0.1N. Formula 3A or Formula 30 alcohol neutralized t o phenolphthalein. Dow-Corning Antifoam A. Phenolphthalein solution, 1%. Procedure. Weigh a sample containing about 6 meq. of aldehyde into a 250-m1., glass-stoppered Erlenmeyer flask. Add 30 ml. of 3% hydrogen peroxide solution (5% for aldehydes above dodecanal). Pipet 10 ml. of 1N sodium hydroxide solution into the flask and add 2 or 3 drops of Antifoam A. Place the flask on a steam bath and stopper after the warm air has been expelled. Heat for 30 minutes with occasional swirling (60 minutes for aldehydes above dodecanol) . After the heating period remove the flask from the steam bath, unstopper, and cool under cold water. Add 50 ml. of Formula 3A alcohol and 5 drops of phenolphthalein indicator to the flask. Titrate with 0.5N standard hydrochloric acid until the pink color of the indicator is just discharged. Run samples in duplicate and also
=
,SI
DISCUSSION AND RESULTS
Calculations.
Bcidity, meq. per gram
EXPERIMENTAL
RCHO
run a reagent blank which is similar in all respects except for the sample. Determine any free acid in the sample by dissolving a separate sample in Formula 3A alcohol and titrating with 0.1N standard alkali using phenolphthalein indicator. Use the amount of free fatty acid found as a correction in the calculations for determining the per cent aldehyde.
yo Aldehyde
yo Aldehyde
by Other
by Oxidation5 Aldehyde Fatty Acid 83.6 i 0 . 6 13) Heptanal 1 0 0ct anal 0.8 99 7 f 0 7 (6) Yonanal 1.0 98 0 f 0 8 (3) Decanal 1.0 98 0 f 0 4 ( 4 ) 98 4 f 0 5 (4) Dodecanal 0.3 Hexadecanal 1.1 9 7 . 2 i 0 . 4 (4) 9 5 . 8 0 . 4 (6) Octadecanal 3.7 95 8 + 0 . 5 (2) Iso-octanal 3.7 9-Octadecenal 5.0 87.2 f 1 . 0 ( 2 ) Xumbers in parentheses indicate number of determinations. Hydroxylamine hydrochloride in isopropyl alcohol. Bisulfite method.
Method 83.Ob 99.7b 96 Gb 9ic 98b,c 9 5b 95b1c 94b
*
b
Table II.
Effect of Ketone and Fatty Acid
Mixture Octanal, octanoic acid, diheptyl ketone
% Acid
% Ketone
Added
Added 10 20 20
20 5 10 20 30 50
50 95
66.6 50
10.5 9.4 8.6
9.8 19.7 29.4
79,7 70.9 63.0
80.1 71.2 62.4
3.8 2.1 3.5 2.0 3.0 2.3 2.0 1.9
...
96.2 93.1 86.0 88.1 78.3 57.5 48.8 23.4
96.3 93.1 82.8 Ei.4 (4.5 48.1 35.8 0.0
... ...
...
...
...
3.4
... Dodecanal, dodecanoic acid, diundecyl ketone Octadecanal, octadecanoic acid, diheptadecyl ketone
4.8 10.5 9.9 18.7 40.2 49.2 74.7
90 80
Found 90.7 80.1 70 5 89.9 81 7 50.7 96.1 91.8 81.2 62.3 38.6
10 10 20 30
Decanal, dinonyl ketone
% Aldehyde Calcd.
70 90 80
90 80
VOL. 29, NO. 1 1 , NOVEMBER 1957
1677
aldehyde to determine the effect of fatty acids and ketones (Table 11). Of the ketones tested, diheptyl, dinonyl, and diundecyl showed no interference in concentrations u p to 20%. Diheptadecyl ketone began to show some effect a t 10.5%. I n practice, the crude samples analyzed by the method rarely contained more than 10% by weight of ketone. Several reaction studies were made (Table 111) to determine the effect of time of the aldehyde determination. Thirty minutes is adequate for aldehydes up through dodecanal, but 60 minutes is needed for higher aldehydes. The end point is sharpened considerably by adding enough Formula 3 4 alcohol just before titrating to make the initial solvent a 1 to 1 alcohol-water miuture. The tendency of the reaction mixture to foam m-as effectively controlled by addition of Dow-Corning Antifoam A. Even jTith this addition, Cla and C18 aldehydes of high purity must be swirled for at least 5 minutes to control the violent foaming. The method has been used for routine control of aldehydes made from fatty acids. It is conceivable t h a t some samples to which the method may be applied may contain esters. Under the alkaline conditions of the oxidation, esters would hydrolyze and consume
Table 111.
Aldehyde
Effect of Reaction Time
Reaction Time, Minutes
yo Aldehyde Found
(6) Fowler, Lewis, Kline, H. R., Mitchell, R. S., Ibid., 27, 1688 (1955).
(7) Frankfurter, G. B., West, R. J., J . Am. Chem. SOC. 27, 714-9 11905). Guenther, Ernest, Langenau, E. E., ANAL.CHEM.25, 12 (1953). Ihid., 27, 672 (1955). Hawthorne. M. F., Ibid., 28. 540 (1956). ' Homer, H. W.,J . SOC.Chem. I n d . 60,213-18 (1941). MacCormac, R.I.,Toxvnsend, D. T. A,, J . Chem. SOC.1940, 151-6;< Mitchell, J., Jr., ed., Organic ilnalysis," Vol. I, Interscience, Kew York, 1953. Mitchell, J., Jr., Smith, D. bl., !LNAL. CHEM. 22, 746-50 (1950). Ponndorf, W.,Ber. 64, 1913 (1931). Ruch, J. E., Johnson, J. B., ANAL. CHEhf. 28, 69 (1956). Satterfield, C. N., Wilson, R . E., LeClair R.M., Reid, R. C., Ibid.. 26. 1792 11954). (18) Schuite, K. E . , Storp, C. B., Fette u . Seifen 57, 36-42 (1955). (19) Ibid., 57, 600-4 (1985). (20) Siegel, H., Weiss, F. T., ANAL CHEM. 26, 917 (1954). (21) Siggia, S., Maxcy, W.,Ibid., 19, 1023-4 (1947). (22) Siggia, S., Segal, E., Ibid., 25, 640 (1953). (23) Siggia, S., Stahl, C. R., Ibid., 27, 1975 (1955). (24) Smith, W, T., Jr., Wagner, E. F., Patterson. J. 11.. Ibid.. 26. 155 (1954). \ - -
~
- 1
I
Dodecanal
5 1.i
30 60 Hexadecanal Octadecanal
D
30 GO 5
15
30 45 BO
120
97.3 98 .. 2 98.2 98.3 95 6 97.7 100.5 ~
82 8 89 0 91 4 92 2
96 3 96.3 96 5 96.5
caustic. A correction for esters could be obtained by running a saponification value. LITERATURE CITED
(1) Bailey, H. C., Xnox, J. H., J . Chem. SOC.1951, 2741-2. (2) Blank, O., Finkelbeiner, H., Ber. 31, 2979-81 (1898). (3) Ihid., 32, 2141 (1899). (4)Biichi, J., Pharm. Acta Helu. 6, 1-54 (19311. (5) Fdwler,Lewis, .ANAL. CHEM. 27, 1686 (1965).
.
RECEIVEDfor review March 19, 1957. Accepted June 24, 1957.
Densities and Refractive Indices for Glycol-Water Solutions Triethylene Glycol, Dipropylene Glycol, and Hexylene Glycol TSU-TAO CHIAO and A. RALPH THOMPSON Department of Chemical Engineering, University of Rhode Island, Kingston, R. 1.
b Analytical data which may b e used for determining compositions of aqueous solutions of three new glycols now available commercially-triethylene glycol, dipropylene glycol, and hexylene glycol-are presented. Densities at 25" C. and refractive indices a t 20" and 25' C. were determined for mixtures of the highly purified glycols and water. Because of the points of inflection in two of the density-composition curves, usefulness of the density data for analytical purposes varies considerably with composition. The refractive index determinations give analyses accurate to within *O.l weight % in the case of all three glycols except for hexylene 1678 *
ANALYTICAL CHEMISTRY
glycol, for which the value is *0.4% above 95% glycol. Applicability of the Eykman equation was tested for the pure compounds at 20' and 25' C. and found very satisfactory.
I
CONNECTION with a distillation project involving some of the newer glycols now available in commercial quantities, i t was necessary to provide a simple b u t precise method for analyzing glycol-water mixtures. The glycols used were triethylene glycol, HOCzH40C2H40CzH40H; dipropylene glycol, O(CHaCHOHCHJ2; and hexylene glycol, also named 2-methyl-2,4-pentanediol or methyl amylene glycol, N
CHsCHOHCHzC(CH8)0HCH3. It was decided that both densities and refractive indices would be determined a t 25" C. over the entire composition range and that refractive index data at 20' C. would also be obtained. Although values of these properties have been reported in the literature (1) for the pure glycols, no data have been given for aqueous solutions. PURIFICATION
OF MATERIALS
Pure grade triethylene glycol (99.7
+ %), dipropylene glycol (99.8 -t %),
+
and hexylene glycol (99.9 %) were fractionated at 10 to 15 mm. of mer-
