642
INDUSTRIAL A N D ENGINEERING CHEMISTRY ACKNOWLEDGMENT
(3)
T h e authors acknowledge the advice of Frank G. Dollear and B. ;ishby Smith for the refining tests made on the hydraulicpressed and solvent-extracted oils. Appreciation is due also to Esler L. D’Aquin for consultations and for the preparation of the hydraulic-pressed oil; to Albert J. Crovetto for assistance in the refining tests; to Walter A. Pons, Jr., Claire Lesslic, and T’idabelle Orr for the analytical determinations on cottonsecd and cottonseed oils; t o hierrill E. Jefferson and Robert T. O’Connor for the spectrophotometric analyses; and t o Joseph L. IIecker for tracing the charts. LITERATURE CITED
(1) B o a t n e r , C. H . , Oil R. S o a p , 21, 1 0 (1944). ( 2 ) Boatner, C. H., Caravella, SI., and K y a m e , L., ISD. ESG. C H E M . , B N A L . ED.,16,566 ( 1 9 4 4 ) .
Vol. 38, No. 6
Boatner, C. H., C a r a w l l a , R l . . and Saniuels, C. S.,J . Am. Chem.
Soc., 66, 838 (1944). (4) Uoutiier, C . H., anti Hall, C . M., Oil R: Soap, i n press. ( 5 ) Clark, E . P., J . B i d . C‘heni.. 76, 229 ( 1 9 2 8 ) . (6) Gullup, \II)., -. O k l n . Agr. Exijt. Sta., R e p ! . 177 ( 1 9 3 4 ) . ( 7 ) Hawis. \\-. D., Bull. A g r . M e c h . C’oll. Tezas, 12, No. 12 ( 1 9 4 1 ) . (S) Hoover, C. \V., Oil Mill Gazetteer, 50, No. 2 ( 1 9 4 5 ) . (9; Ol(’f>tt,11. Y.. ISD. E S G . CHEM., 33, 6 1 1 (1941). (10) O ~ . h o r nT, . B., and Mendel. L. B., J . B i d . Chem., 2 9 , 2 8 9 ( 1 9 1 7 ) . (11) Owen, G . IT., Oil & S o a p . 14, 149 ( 1 9 3 7 ) . (12) Podol’ska.ya, RI. 2.. and Tobler, L., Muslobolno-Zhiroooe D e b ,
16, No. 4 , 5 , 7 ( 1 9 3 0 ) . (13) Pollard, E . F., Vix, H. I,. E . , and Gastrock, E. 9., IND. ENQ.
CHEM.. 37, 1022 (1948). (14) Itoscnthal, Henry, U. S. P a t e n t 2 , 2 5 4 , 2 4 5 ( S e p t . 2, 1 9 4 1 ) . (15) Royce, H. D., and Lindsey, F. .4.,Jr., ISD. ENQ.CHEM.,25, 1047 ( 1 9 3 3 ) . (16) Shrader, J. H., Cotion Oil Press, 4, No. 1 2 , 42 ( 1 9 2 1 ) . (17) Thurman, B. IT., ISD.EXG.CHmf.. 24, 1187 ( 1 9 3 2 ) . 1 li;) W e s o n , D., Oil c t F a t l n d i t a t r i e s , 7 , 217 ( 1 9 3 0 ) . ( I n 1 TT-crson. I)., Oil & S o n p , 10, 151 ( 1 9 3 3 ) .
Solubilization of Insoluble Organic Liquids by Detergents J-4.IRIES W.I\IcB,IIN .AND PaicTLH. RICHARDS Stanford University, Calif.
Solubilization is attributed to incorporation of the insoluble substance \+ ithin and upon the colloidal particles o r micelles of the soap or detergent. Although many instances of this action hale been reported, this is the first attempt at a systematic investigation of the characteristics of an insoluble organic substance that determine the ertent to which it is solubilized. 4 number of cation-actile and anion-actile detergents hale been used with a series of aliphatic and aromatic hydrocarbons, in addition to a number of polar compounds. Substances of Fery low inolecular weight are freely solubilized, but the extent of solubilization falls off rapidly with increase in molecular weight or molar volume. Polar compounds arc more readily solubilized than hydrocarbons. .\lthough, in general, the various detergents show parallel behavior, merely differing in degree of solubilizing power, and the cation-active detergents are generally better solubilizers than the anion-active detergents, there are numerous specificities and influences of structure, both of the detergent and of the material being solubilized. Soaps and detergents that have in common the twelve-carbon paraffin chain differ greatly in solubilizing power, each favoring particular classes of chemical substances.
T
HE remarkable phenomenon of solubilization ( 3 )consists in the taking up, by even very dilute solutions of soaps and detergents, substances yhich are otherwise insoluble or very slightly soluble in the solvent medium. Indeed, it is probable that any substance can be made soluble in any medium by the use of a suitable solubilizing agent. The solubilized material is in solution in the sense that it is not present as suspended or protected particles or emulsified droplets, b u t is incorporated in the colloidal particles of the detergent itself. It is therefore in solution in the same sense that the soap itself is in solution. At least a portion of the solubilized material has been shown by x-ray examination (1, 2, 6) t o be present in layers within the lamellar micelles of the detergent.
‘1s soon as tlit. wtur:ttion valuc lor solubilization is exceeded, of the rolubilizcd material appears as suspended particles or droplets of cmul.ion and causes a steep rise in turbidity. At the suggestion of one of the authors (liiehartls), this point of sharp increayc, in turbidity 1x1s been used as an indicator for the maximum amount of n given material that can he solubilized by a given detergent qolution a t a given tempomtiire and concentration. This communication contains the first systematic survcy of the amount of solubilization of different organic liquids as depending upon such factors as molecular weight and structural and chemical composition. Decinormal aqueous solutions of sodium oleate, potassium laurate, and cation-active dodecylamine hydrochloride hare been used wit,h all the organic liquids. -4number of rneusurements n.ith other synthetic detergents, Gardinol K.1 new, concentrated (containing sodium lauryl sulfate and salts), and the ration-active Emulsol 607L and cetyl pyridinium chloride have also been included. !lost of the results follow general rules, but a few specific relations also appear. BIATERIALS AND hIETHOD
1)odecj-laiiiinc hydrochloride was prepared from a fairly pure dodecylamine obtained from Xrmour & Company, and was twice recrystallized from ethyl alcohol and washed with ether. Sodium oleate was prepared from Kahlbaum’s ‘(pure” oleic acid, and a 10% solution in acetone was cooled t o -20” C. to precipitate out linoleic acid. Oleic acid ivas recovered from the filtrate and converted by carbonate-free sodium hydroxide to sodium oleate. Potaspiurn lsuvate v a s a Kahlbaum preparation, rectified and purified by 11. E. L. hIcRain. Emulsol 607L was a purified specimen and was the lauryl ester of a-alanine hydrochloride supplied by the Emul9ol Corporation. Cetyl pyridinium chloride was used as purified and supplied by the Wm. 8. llerreu Company. Gardinol WT‘X new, cone., was used as supplied by the Sational Aniline &: Chemical Company; unlike the others, the active substance, sodium lauryl sulfate, may be only one third of the total weight, and salt,? are present.
lune, 1946
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
643
1.2, cetyl pyridinium chloride 1.4, and Gardinol WA new, OF ORGANIC LIQUIDSBY DECINORMAL conc., 1.8. TABLEI. SOLUBILIZATION AQUEOUSSOLUTIONS OF DODECYLAMINE HYDROCHLORIDE The results are listed in Tables I to 17. The amount of orAT 25" C. ganic liquid soluble in pure water at' the same temperature has Soly. Total in Amount Solubiliied been subtracted from all results. I n Table I the organic liquids Mole/ in Water, Solution Grama/ 100 mole G./100 Xl./lO0 are numbered serially for comparison with later tables and with Cc. detergent cc. Co. Figure 1. Paraffinic liquids This paper is not so much concerned with discussing tho mecha0.64 0.75 1.00 1. n-Hexane 0.014 0.54 0.54 0,005 0.80 2. n-Heptane nism of solubilization as in discovering relationships between 0.33 0.29 0.48 3. n-Octane 0.002 0.22 0.29 0.000 0.40 4. n-Nonane chemical nature and amount of solubilization. However, it may 0.13 0.18 0.24 0.000 5. n-Decane be recalled that solubilization by colloidal electrolytes differs from 0.11 0.06 0 14 0.000 6. n-Dodecane 0.01 0.02 0.02 0.000 7. n-Tetradecane the hydrotropic effect of adding large quantities of concentrated 0.00 0.00 0.000 0.00 8. n-Cetane solutions of a good solvent in that very dilute solutions of t h e 0.73 0.Y6 0.63 0.000 9. 0.75 0.64 0.000 0.98 10. detergent have as much effect as large additions, such as 307, 0 53 0 62 0.000 0.90 11. or more, of a good solvent used to change the liquid medium. 5 5 0.55 0 0 000 0 . 8 0 12. 0 30 0.27 0.000 0.44 13. Furthermore, solubilization is not due to molecular solution but 0 . 3 4 0 . 3 0 0 . 0 0 0 0 . 4 8 2.2.3-Tri niethylpentane 14. 0.48 0.43 0.60 0.000 15. Diiaobutylene to incorporation within or upon the colloidal particles of the de0.37 0.50 0.40 0,000 16. Methylcyclopentane tergent (8). 17. 18.
Cyclohexane 1,2,4-Trimethylcyclohexane
Aromatic liquids 19. Benzene 20. Toluene 21. Nitrohenaene 22. Ethylhenmne 23. p X y l e n e 24. Anirlbenzene 25, p-Cymene Polar comnounds 26. .\Idthy1 lert-butyl ether 27. Methyl iaohutyl ketone 28. Amyl acetate 29. Isopropyl tsrt-butyl ether 30. Octylamine ~
31. 32. 33. 34. 35. 36.
n-Octyl alcohol Z-Eth&lhersnol Lauryl alcohol Oleic acid Tributyrin Triolein
0.000
0.98
0.73
0.87
0.000
0.03
0.02
0.02
COMPARISON OF LIQUIDS SOLUBILIZED B Y ONE SOAP
0,070 0.049
0 66 0.58
0.51
The outstanding result of this investigation is the finding that increase in molecular weight within any homologous series niili-
0.GO
0.53
0 014 0.013 0.000 0.000
0 48 0.44 0.20 0.30
0.36 0.17 0.26
0.65 0.49 0 43 0.38 0.34 0 12 0 19
5.126 1.820 O.li3
9.30 2.14
1.80 1.i8 1.69
2.05 1.78 1.45
0,050 0.020
0.90 0.24
0 62 0.17
0.53 0.13
0,059 0.013 0.000 0,000 0.000 0.000
0.36 0.58 0.10 0.08 0.66 0.00
0.24 0.47 0 08 0.07 0.68 0.00
0.18 0.36 0.05 0.02 0.22
0.190
0.45
0.40
TABLEIT. SOLEBILIZATIOS OF ORGAKICLIQUIDEBY 4.50
DECISOIIMAL AQCEOCS SOLUTIOSS OF SODIUM OLEATE AND OF POTASSIUM LAURATE AT 25' C.
Li uid do.
1 2
3 4
5 6
Immeasurable.
7 8 9 10
Sodium Oleate Amount soluhilized Mole/ mole G./100 cc. cc. rletergent 0.398 0.6 0 46 0.5 0.34 0.340 0.3 0.210 0.18 0.142 0.2 0.11 1 0.047 0.05 0.02 0.015 0.01 0.00 0.000 0.00
Total in solution, m1./100
...
...
...
0.60
0.386 0.394 0.350 0.312 0.178 0.205 0.428 0.244 0.465 0.014 0.594 0 486 0.768 0.419 0,383 0.257 0.342 1.936 1.820 1.990 0.858 0,088
0.45 0.45 0.35 0.31 0.16
0.60
Potassium L a u r a L ~ ~in -Amount t ~ aoluhiliaed l rolution, Mole/ m1./100 0./100 m d cc. cc. detergent 0 . I56 0.26 0.18 0.18 0.117 0.12 0.14 0.096 0.08 0.10 0.071 0.06 0.06 0.045 0.03 0.01 0.008 0.005 0.00 0.000 0.00
...
...
0.18 0.20 0.16 0.14
0 . 116
0.121
...
0.13 0.14
11 0.50 6.110 0.11 The thirty-six organic compounds used were the purest ob12 0.45 0.097 0 . le 13 0.26 0.08 0.055 0.08 tainable. Some of them n-ere specially supplied by Shell Develop14 0.28 0.18 0.14 0.110 0.09 15 0.60 ment Company. They comprise eighteen aliphatic hydrocar0.38 0.16 0.114 0.10 16 bons, seven aromatic hydrocarbons, and a number of polar com0.32 0.26 0.04 a . 030 8.38 17 0.60 0 56 0.26 e. 194 0.23 pounds. 18 0.02 0.012 0.02 8.015 e.om A series of 10-cc. samples of soap solution m r e measured into 19 0.70 0.76 0.28 0.226 8.28 20 0.60 0.51 0.25 0.116 0.13 small glass bottles with plastic caps lined with platinum foil, and 0.80 21 0.62 0.27 0.183 0.18 22 0.50 knoivn amounts of thc organic compound were added from a 0.40 0.30 0.214 0.20 23 0.46 0.36 0.26 8.210 0.20 microburet reading to 0.001 cc. They were placed on a gentle 24 0.30 0.17 0.06 0.051 0.04 25 0.40 0.26 0.12 0.103 0.08 shaker overnight. Thereupon the turbidity was measured in 26 9.50 2.20 7.50 1.460 1.86 a Barnes turbidimeter ( 4 ) . This instrument, designed in the 27 4.55 1.200 1.82 4.00 1.20 2.70 28 laboratories of the American Cyanamid Company, meas1.038 1.71 1.20 0.89 1.22 29 0.73 0.24 0.166 0.14 ures the turbidity or.scattered light as a percentage of the 30 0.14 0.07 0.814 0.088 0.07 total light passed through a 1-em.-thick plane-parallel cell. 31 1.00 0.764 0.59 0.54 0.385 0.29 32 0.75 0 610 0.10 0.47 0.083 0.064 The percentage turbidity of the detergent solution remains prac33 0.25 0.206 0.13 0.06 0.049 0.03 34 0.16 tically constant until a saturation value for solubility i-; just 0.137 0.05 0.06 0.051 0.018 1.10 35 1.124 0.37 0.32 0,327 0.11 exceeded, xvhereupon the turbidity rises 36 0.00 0.000 0.00 ... sharply and careful inspection reveal> the presence of emulsified droplets. TABLE111. SOLCBILIZATION OF ORQANIC LIQCIDSBY DECINORMAL AQUEOUS All the experiments when not otherwise SOLUTIOSS OF EMCLSOL 607L, CETYLPYRIDIXICM CHLORIDE, A N D GARDINOL WA NEW, CONC. stated n-ere conducted a t 25 O C. in an air thermostat which also contained the Gardinol W A
shaker. Decinormal solutions of detergent were employed. From 3 to 5 hours were neceseary t o reach the equilibrium point, and thereafter the results did not change. The turbidities of the decinormal solution without admixture were: dodecylamine hydrochloride 1.2, sodium oleate 4.9, potassium laurate
Liquid No. 1 5 19
20 30 31
34
Eniulsol 607L Total in Amount solubilized solution, Grams/ Mole/ m1./100 100 mole CC. eo. detergent 0.38 0.235 0.27 0.12 0.089 0.062 0.70 0.540 0.69 0.70 0.534 0.58 0.35 0.252 0.20 0.95 0.723 0,56 0.04 0.034 0.012
Cetyl Pyridinium Chloride ~ ~in t Amount ~ lsolubilized solution. Grams/ Mole/ m1./100 100 mole cc. cc. detergent 0.66 0.418 0.49 0.25 0.193 0.14 (3.74 0.577 0.74 0.74 0.588 0.64 2.60 2.001.55 1.10 0.835 0.66 0.22 0.188 0.065
New, Conc. T~~~~ in Grama solution aolublllsed ml./lod per 100 0.34
cc. 0.209
0.30
...
0 : i92
0.08
... ...
0: 042
...
cc.
...
...
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
644
MOLS SOLUBILIZED
hu.
Ai(-
ON
I
LOMPOUN D ".HEXANE
Ma. WT.
6
86
2
,.HEPTANE
7
IO(
3
..OCTANE
8
I14
4
n-NONANE
P
I2€
5 ,.DECANE 6
,.DODECANE
7 -,,.TETRADECANE 0
*CETANE
10
I4i
I2
17c
14
19:
I6
r21
9
2,Z-DI ME 7 HY L BUTA N E
b
86
I0
2,3-
6
86
I
2,3-
7
I oc
I
PEN T I NE
7
IO0
8
114
14 2,2,3- "
0
1 i4
15 D I I S O B U T Y L E N E
8
16 M E T H Y L CYCLOPENTANE
6
94
17 C Y C L O H E X A N E
6
04
I2 3,3-
"
I3 Yfl-TRIMETHYL
"
i,'/
I /
P E R MOL D E T E R G E N T
tx l oI I i I I
-
L
0
18
I,Zs4-TRIMETHYL CYCLOHE)
9
126
I9
BENZENE
6
76
7
92
21
NITROBENZENE
6
12.
22
ETHYLBENZENE
8
I Ot
23
p-XYLENE
8
IO(
24
AMYLBENZENE
II
14f
25
p.CYMENE
IO
131
26
METHYL TERT-WTYL E W E
5
a0
METHYL lSO8UTYL
6
IO
6
lit
7
I I.
12 i
20 T O L U E N E
27
2 8 AMYL
KETOh
ACETATE
2 9 I S 0 PROP.TERT-BUTYLETHE 30
OCTYL AMINE
0
31
wOCTYL
0
13(
0
l I3(
32
ALCOHOL
z-ETHYL
33 LAURYL
tiEXANOL
ALCOHOL
I2
3 4 OLEIC A C I D
IE
35 I T R I B U T Y R I N
I5
-n o m
112
_.--
1, 30
Figure 1. Solubilizatioll of 'Thirt?-fi%eOrganic, Liquids t)> \queolrs Yolutions of Five + o a p n r l d Detergents ( T w o inion-ac t i \ e HIXI l'hrre Cation-active) The data are incornplete for two of the detergents, and onl, the experimental points are indicated The solubilization is expressed in p r a m moles solubilized per gram equivalent of deterrent. Molecular weight a n d the number of carhon atoms are given for each compound.
Vol. 38, No. 6
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
lune, 1946
T ~ B LIv. E CO.MPARISO.\ O F r T \ I B E R LIQUIDSOLI-BILIZED P E R 1IOI.E J,iquid SO.
No. of .itom.
2
I
3
?
69
2
10 12 14 I6
Y
I3 Ii
0 46
0.54 0,2'l 0.22 0 13
14
k8
i5
8
16 l i
6 6 9
0.40 0.8i 0,019
2
0.65 0.49 0.43 0 38
10 'I .2 13
18 i I4
LO
5;
23 24 25 26 '7 28 I $1 .3(l .3 I
32 33 34 35
.6i
,
hClS 8 8 11
IO 5 (1 u 6 (1 0,
6 (3 0 ) 7 ( 10 ) 8(1N
8 (1 0 ) 8 (1 0: 12 (1 01 18 ( 2 02 lj(6O 57 (6 0
0 2i
CeP\ 0 4!1
0 063
0
0 6'i 0 38
0.74 0.64
XdC...
C:2IICI 0.73
0 063 0.008 0.000 0 73 0.75 0.02 0.55 0.2i 0.30 0 43
b
OF h l O L E S OF OIlGhSlC O F DETtRC.ENTa
0.34 0 18 0 11 0 052 0 009 0 000 I ) .4,5
0.46 1) 35 0 31 0 . 10 0.18 0.38 0 . 26 0.56 0.012 0.iti
13 51
n.02 0 40
0.34 0 12
0.1Q 2.05 I.is L45
0.53 0.13 0.18 0.36 0.052 0,024 0.22 0 00
0.3; O,l, 0.26 8.20 1.82 1.i l
0 73 0.0i 0.59 0.47 0.13 0.05 0.3i 0 00
0 0 0 0 0
18 12 08 Oh
03
0 00i
I 3 0 I4 0 11 0 10 0 05 0 09 0 10 0 032 0 23 0 012 0 29 0 13 0 18 0 20 0 20 0 0.1 D 08 1 66 1 20 0 85 0 14 0 0i 0 29 0 061 0 03 0 016 0 11
ii
I)
... ..
0 20 0 56
0.6ti
0 012
I)'
1.55
..
oii:
ClzHC'I = dudecylaniine hydrochloride, SaCia = .?odiuru oleahe, KCi? = putabeiuni laurate, eniulsol Emulsol BOiL, CeP?- = cetyl pyridinium
645
carbons. (There is a negative effect for nitrogen-containing compounds.) This is especially marked for those of low moleculhr weight, such as methyl tert-butyl ether, methyl isobutyl ketone, and amyl acetate. However, here, too, differences in configuration are important. Two compounds with eight carbon atoms and one oxygen are 2-ethylhexanol and n-octyl alcohol, and of these the former is solubilized t,o tn-ice the extent of the latter. These numbers have been, perhaps arbitrarily, corrected for natural solubility in water. S o simple relation has yet appeared between any single property of solubilized material and the extent t o which it is solubilized by a given detergent. Solubilization appears to fall off a t first linearly with molar volume and then to fall more slowly and a.ymtotically to zero for the higher members. However, closer examination shows that molecular volume may exert more influence than molecular I-ieight. This is illustrated in Table V n-here hydrocarbons of iderit ical molecular wright but different structure are conipnretl. It i.q evident, that a branched chain can be solubilized to a greater extent than the straight chain of the same molecular might. However, molecular volume of itself does uot determine solubilization. Table I? compares groups of substances of similar molecular volume and s h o w that their degree of solubilization may differ greatly. The extent of solubilization of an organic chemical depends not only upon lox molecular weight, upon molecular volume, upon structure, and upon the presence or nature or position of any polar groups, but also sometimes upon a
1
5
c,hlnride.
rates strongly against solubilization. Substances of high riiolixu!ar neight are scarcely solubilized; n-hereas all the compounds of low molecular weight so far investigated are freely solubilized. As an example, dodecylamine hydrochloride solubilizes the hydrocarbons with six carbon atoms to the extent of 0.75 mole of hydrocarbon per niolc of detergent; niethglcyclopentane differs :n being as lovi as 0.40 n-hile %yclohexane is high, 0.87 mole pel mole, an indication that configuration likewise has a decided influence. Steric effects must interfere n-ith close packing. Simi!arly the results for the hydrocarbons nith eight carbon atoms, xhether paraffinic, branched-chain, or aromatic, all range between 0.27 and 0.43 mole per mole, the higheat being diisobutg1 , f j r i t A anti the lowest the less symmetrical 3,2,~-triniethS.lpentanc..
T ~ B L y. F EFFECTO F hlOLECELAR r r E I G H T A S D S-OLEMEo s SOLUBILIZATION S O
I 9 10
2 I1 12
3 13 I?
Compouno 1,-Hexane 2.2-Dimethylbutane 2.3-Dimethylbutane ti-Heptane 2,3-Dimeth>-lpentane 3.3-Dimethylpentanr ii-Octane 2.2.4-Trimeth>-lpentane 2.',3-Trimeth~lpeiitane
Alolecular Molar Weight Volume ClzHCl NaC,, 86.1 131.3 0 75 0.46 86,l 133.t 0.73 0.44 86.1 131.1 0.75 0.45 100 2 147.1 0.54 0 34 100.2 144.1 0 62 0 35 100.2 146.1 0 55 0.31 114.23 163.3 0 29 0.18 114.23 165.7 0.27 0.16 114.23 160.4 0.30 0.18
KClX 0.18 0.13 0.14
0.12 0.11 0.10 0.08 0.05 0.09
TABLEVI.
COMPARISON O F SOLUBILIZATION O F GROUPSO F SUBSTANCES O F SIblIL.4R h1OLECCLAR VOLUME BY DODECYLdYINE HYDROCHLORIDE, S O D I V M OLEATE. A N 0 P0TAsSIW.M LAUR'4TE S0
li 2(J
215 22 27 1
'18 25 29 $1
Compound Cyclohexane Toluene I f e t h y l kri-hutyl ether Ethylbenzene l I e t h y l isobutyl ketoiir n-Hexane Amyl acetatr p-Cymene Isopropyl f c r l - h u t b l r t h e r n-Octyl alcohol
3 13 18
30 24 5 33 8 34 35
n-Decane Lauryl alrohol n-Cetane Oleic acid Tributyrin
Ilolar Volume 108.5 106.7 118 122.5 125.0 131.3 134.1
156.5 157.3 157.8 163.3 165.7 164.9 166.0 172.7 191.4 191.7
293.5 339.6 295.7
hfole/Mole Ratio NaCir KC;p 0.8i 0.56 0.23 0.49 0.51 0.13 2.05 2.20 1.66 0.38 0.40 0 20 1.78 1.82 1 20 0.75 0.46 0.18 1.45 1.71 0.89
CZiCl
O,l9 0.53 0.18 0.29 0.27 0.019 0.13 0.12 0.13 0.052 0.00 0.024 0.22
0.26 0.73 0.69
0.18 0 16 0 012 0 07 0 17 0.05 0.13
0.00 0.05 0.37
0.08 0.14 0.29 0.08 0.05 0.012 0.07 0.04 0.03 0.03 0.00 0.018 0.11
direct interaction with the detergent. This must operate in the formation of certain acid soaps from fatty acid and soap; but in the prcsent work a good example is found in the interact>ionbetween octyl amine and cetyl pyridinium chloride. This results in the abnormally high mole/mole ratio of 1.55 and is evidenced in a color change to a different tone of yellow observed in t,his solution. COMPARISON OF DETERGENTS
The re..ults are given in Figure 1, where the number of inole+ < i f organic liquids solubilized by five detergents are graphed. The series ior normal hydrocarbons shows the effect of increasing mo1ccul:ir weight in loivering the value for n-hexane from 0.75
