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Hydrophilicity and critical micelle concentration of polyoxyethylene 4-alkylphenylamines
Colloids and Surfaces, 49 (1990) 363-371 Elsevier Science Publishers B.V., Amsterdam
363
Hydrophilicity and Critical Micelle Concentration of Polyoxyethylene 4-Alkylphenylamines MACIEJ WISNIEWSKI Technical University of Poznari, Institute of Chemical Technology and Engineering, Sktodowskiej-Curie 2, 60-965 Poznali (Poland) (Received 27 September 1989; accepted 24 January 1990 1
ABSTRACT Surface tension isotherms were determined for polydisperse polyoxyethylene 4-alkylphenylamines. For these products the critical micelle concentration was used to determine the effective length of the hydrophobe in comparison with the standard individual polyoxyethylene glycol monoalkyl ethers. The hydrophobicity increments for the structural fragments of polyoxyethylene 4-alkylphenylamines are equivalent to the following numbers of the methylene groups in the standard polyoxyethylene glycol monoalkyl ethers [CH,]: CH2=0.42 [CH,], Ph-N=0.9 [CH,], Phz4.6 [CH,] andN= -3.7 [CH,].
INTRODUCTION
4-Alkylphenylamines exhibit interesting extraction properties and can be used as group reagents for extraction of noble metals, i.e., gold, palladium, iridium, ruthenium and rhodium [l-lo]. These reagents can be also used as intermediates to obtain other compounds, i.e., (4_alkylphenyl)trimethylammonium halides which, as quaternary salts, also exhibit surface-active and bactericidal properties [ 11-141. Recently, polydisperse polyoxyethylene 4-alkylphenylamines were obtained from 4-alkylphenylamines and ethylene oxide, and their usage, properties and polarity parameters were described [ 15,161. Mass spectrometry-gas chromatography techniques were used to identify the components of these polydisperse products, and gas chromatography was used to determine the contents of the successive homologues with various numbers of oxyethylene units as well as the contents of polyoxyethylene glycols formed as by-products [ 17,181. The aim of this work is to determine the surface tension isotherms and critical micelle concentrations for polydisperse polyoxyethylene 4-alkylphenylamines containing from 1 to 16 carbon atoms in the alkyl group and from 1 to
0166.6622/90/$03.50
0 1990 -
Elsevier Science Publishers B.V.
364 8 average number of oxyethylene units in both oxyethylene chains, and to use these data to estimate the structural increments of hydrophobicity. EXPERIMENTAL
Twenty-two polyoxyethylene 4-alkylphenylamines were used. Their compositions as determined by gas chromatography have been given previously [17]. Surface tension was measured at 20 ° C using the ring method. Solutions were poured into glass vessels 8 cm in diameter and I cm high. The solution surface was carefully sucked off with a capillary tube. The solution was then kept for 24 h and the surface tension was measured. All polyoxyethylene 4-alkylphenylamines containing five and eight oxyethylene groups were well soluble in water. For other amines containing one and three oxyethylene groups methanolic solutions of 1-2 mg cm -3 were first prepared. Then 1 cm 3 of this solution was diluted with redistilled water to 100 cm 3 and used to obtain successively lower concentrations. The critical miceUe concentrations were determined from the surface tension isotherms. The molecular area at the saturated interface was determined from the surface excess calculated according to the Gibbs isotherms: dy Fm~-dlnc
1 1 R T and A = N F~
where N is the Avogadro number, Fm~ the surface excess at the saturated interface, dy/d In c the maximum slope of the surface tension isotherm, R the gas constant and T the absolute temperature. RESULTS AND DISCUSSION Surface tension isotherms obtained for the investigated products are presented in Figs 1-4. The values of the critical miceUe concentrations of the surface excess and of the molecular area are given in Table 1. Lower values of the surface tension at the c.m.c, and lower values of the c.m.c, are obtained for more hydrophobic compounds having a long alkyl group in comparison to hydrophilic compounds having a short alkyl group. The surface excess increases and the molecular area decreases significantly (approximately three times) as the alkyl length increases from the methyl to dodecyl group. The length of the polyoxyethylene groups has a relatively weak effect and only a small decrease of the surface excess and a small increase of the molecular areas are observed as the average degree of ethoxylation increases from I to 8 (approximately 30% ).
365
I
60.
E
5
B
:
'g 50. J 78 e 40. I 30.
3
4
2
-loge
Fig. 1. Surface tension isotherms for polyoxyethylene 4-hexylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation ) .
5
4
3
-
log c
Fig. 2. Surface tension isotherms for polyoxyethylene 4-octylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation).
The c.m.c. also changes in a typical way, i.e. straight-line relations with high and low slopes are obtained as log c.m.c. is correlated with the number of carbon atoms in the alkyl group (m) and the average degree of ethoxylation, respectively. The overall relationship correlating c.m.c. with the number of oxyethylene groups (n) is as follows:
366
J d
z
z 40.
30-
Fig. 3. Surface tension isotherms for polyoxyethylene 4-decylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation).
Fig. 4. Surface tension isotherms for polyoxyethylene 4-dodecylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation ) .
log c.m.c. = -2.37-0.17m+O.lOri where the constant -2.37 also takes into account the effect of the aromatic ring and the nitrogen atom present in the polyoxyethylene 4-alkylphenylamines, and the c.m.c. is given in mol dmb3. This relationship is statistically valid, as is shown in Table 2 and Fig. 5, although some important deviations are observed. Only one value of the c.m.c.
367 TABLE 1 Parameters characterizing the adsorption of polyoxyethylene 4alkylphenylamines at the air/water interface Alkyl group
Ethoxylation degree
Surface tension at c.m.c. (mN m-‘)
c.m.c. (mm01 dme3)
W-b3 W-b, &OH,, C12H2,
CH3 ‘G&3 GJ-L GoH21 G2H2,
CH3 W-b3 W-L GoH2, G2H2,
CH3 C&I, U-L GoH21 C12H25
Molecular area at the c.m.c. ( 1020m2)
31.7 30.0 28.1 26.8
6.000 0.840 0.314 0.098 0.053
1.32 2.99 3.72 4.72 4.77
125.6 55.5 44.7 35.2 34.8
40.5 32.8 30.6 28.9 17.8
10.500 1.210 0.410 0.210 0.060
1.34 2.84 3.63 4.09 4.49
124.2 58.4 45.8 40.6 37.0
41.5 33.3 32.1 31.0 29.5
11.500 1.585 0.631 0.458 0.066
1.23 2.78 3.28 3.80 4.42
135.2 59.7 50.6 43.7 37.6
42.0 35.3 33.9 32.7 31.5
16.100 2.400 1.149 0.945 0.070
1.13 2.48 2.79 3.73 4.51
146.9
39.0
CH3
Surface excess at the c.m.c. (pm01 m-‘)
67.0 59.5 44.5 36.8
TABLE 2 Statistical assessment for the relation correlating the c.m.c. with the length of the alkyl group and the average degree of ethoxylation Constant
-2.37 -0.17 0.10
Limits for 95% confidence intervals lower
upper
- 2.72 - 0.20 0.05
-2.01 -0.14 0.15
Standard error
Significance level
0.169 0.016 0.024
0.0000 0.0000 0.0008
-,tllllllllll,lllrl,Illllllrlllll -4.4 -3.9 -34 -2.9 -2.4 Predicted
-4.9
-4.4
CMC
Fig. 5. Comparison of the experimental and predicted values of the c.m.c.: ( l ) experimental values; (-) fitted relation; vertical lines denote 95% confidence intervals.
from 20 considered is outside the 95% confidence interval, while the other values of the c.m.c. are near the fitted relation. The values of the c.m.c. can be used to determine the equivalent length of the hydrophobic groups in polyoxyethylene 4alkylphenylamines i.n comparison to polyoxyethylene glycol monoalkyl ethers considered as the standard homologue series. For these last compounds the following relationship was obtained [ 191 using the literature data [ 20,211: logc.m.c.=7.79-0.47m+O.O47(n-6) where m and n denote the number of carbon atoms in the alkyl group and the number of oxyethylene groups, respectively, and the c.m.c. is given in pmol dmW3.Rearranging this equation the following relationship for the length of the alkyl chain can be obtained: m= 15.97+0.X-2.13
log c.m.c.
Introducing into this equation the values of the c.m.c. and average numbers of oxyethylene units, fi, for the polyoxyethylene 4-alkylphenylamines the equivalent length of their hydrophobes (mea) was calculated. This takes into account the length of the alkyl group, the aromatic ring and the nitrogen atom present in the molecules and determines the number of carbon atoms in hypothetical polyoxyethylene glycol monoalkyl ethers having the same c.m.c. as the considered polyoxyethylene amines. The effect of the length of the polyoxyethylene chain upon the determined values of the effective length of the hydrophobe is relatively weak (Table 3) and can be neglected. In this case the simple relationship between both actual
TABLE 3 Effective length of the hydrophohe in polyoxyethylene glycol monoalkyl ethers as the standard compounds )
4-alkylphenylamines
(polyoxyethylene
m
?i=l
ri=3
ri=5
n=8
Average k
1 6 8 10 12
1.63 3.46 4.36 5.44 6.00
1.32 3.31 4.32 4.43 6.10
1.44 3.27 4.12 4.41 6.21
1.42 3.18 3.86
1.5 3.3 4.2 4.7 6.2
6.45
6.
Fig. 6. Effective length of the hydrophobe for polyoxyethylene
t;i
4dkylphenylamines.
y)d effective (meff) alkyl length can be derived with the slope of 0.42 1.
.
meff=0.9+0.42m Thus much lower valuesof the effective lengthof hydrophobesin the polyosyethylene 4alkylphenylamines were obtained in comparison to the chosen standardseries of polyosyethylene glycol monoalkyl ethers. For m=O,meff= 0.9[ CH2]. This means that the CBHbNgroup is equivalent only to approximatelyone methylene group, owing to the strong hydrophilic effect of the nitrogen atom. For (4alkylphenyl) trimethylammoniumhalides the hydrophobiceffect of the aromaticring was previouslyestimatedas equivalent to about 3.3-5.4 methylenegroups [ 111. Thus, if the averagevalue 4.6 is taken then the nitrogen atom in polyosyethylene 4-alkylphenylaminesis equivalentto approximately - 3.7 [ CH,].
370 Similar strong polar effects of the nitrogen atom upon the polarity of various amines containing oligooxyethylene chains were observed using gas chromatography [16]. CONCLUSIONS
The c.m.c, of the polyoxyethylene 4-alkylphenylamines is correlated with the length of the alkyl group (m) and the average degree of ethoxylation (rD according to the following linear equation: log c.m.c. = - 2.37- 0.17m + 0.10~ The nitrogen atom in the considered amines causes a significant increase in the hydrophilicity of polyoxyethylene amines in comparison to the polyoxyethylene glycol monoalkyl ethers taken as standard compounds. The nitrogen atom present in the molecule exhibits a very high hydrophilicity, equivalent to - 3 . 7 [CH2], i.e. methylene groups in the standard polyoxyethylene glycol monoalkyl ethers. As a result the P h - N group is equivalent to only approximately one methylene group. The estimated hydrophobic effects for the structural fragments of polyoxyethylene 4-alkylphenylamines are equivalent to the following numbers of methylene groups in the standard polyoxyethylene glycol monoalkyl ethers, [CH2 ]: CH2 = 0.32 [CH2 ], P h - N = 0.9 [CH 2] Ph ~ 4.6 [CH2 ] N = - 3 . 7 [CH2]. ACKNOWLEDGEMENT This work was supported by Polish Research Program CPBP No 03.08.
REFERENCES I A.A. Vasilyeva, I.G. Yudelevich, I.M. Gindin, T.V. Lanbina, R.S. Shulman, I.L.Kotlarevski and V.N. Andrievsky, Talanta, 22 (1975) 745. 2 C. Pohland, Talanta, 26 (1979) 199. 3 C. Pohland, S.A. Natl. Inst.Metalurgy, Johannesburg, Rept. No. 1991 (1977). 4 C. Pohland, H. Hegetschweiler and T.W. Steele,S.A. Natl. Inst. Metallurgy, Johannesburg, Rept. No. 1940 (1978). 5 B. Weaver, Ion Exchange and Solvent Extraction, Marcel Dekker, New York, 1974. 6 M. Cleare, P. Charlesworth and D.J. Bryson, J. Chem. Tech. Biotechnol.,29 (1979) 210. 7 G.M. Ritcey and A.W. Ashbrook, Solvent Extraction, Part II,Elsevier,Amsterdam, 1979. 8 M. Wi~niewski and J. Szymanowski, Przem. Chem., 65 (1986) 591. 9 A.A. Vasilyeva, V.G. Torgov, N.K. Kalish, L.V. Zelentsova, T.M. Korda, N.V. Maksimova and I.G. Yudelevich, Proc. ISEC 88, Moscow, USSR, Vol. 4, Nauka, Muscow, 1988, p. 100. 10 M. Wi~niewski, Pol. J. Chem., 57 (!983) 593. 11 M. Wi~niwski, J. Colloid Interface Sci.,128 (1989) 115.
371 12 13 14 15 16 17 18 19 20 21
M. Wisniewski, B. Nowak, B. Kedzia and J. Szymanowski, Tenside Deterg., 24 (1986) 46. C.A. Lawrence, Quaternary Ammonium Active Disinfectants, Lea and Febiger, Philadelphia, PA, 1968. M. Wis’niewski and J. Szymanowski, 2nd World Surfactants Congress, Surfactants in our World Today and Tomorrow, ASPA, Paris, France, 1988. M. Wilniewski, Chem. Stosowana, 32 (1988) 503. M. Wisniewski and J. Szymanowski, Colloid Polym. Sci., 59 (1989) 267. M. Wisniewski, J. Szymanowski and B. Atamanczuk, J. Chromatogr., 462 (1989) 39. M. Wibiewski, J. Szymanowski and E. Dziwiriski, Chem. Anal., in press. I. Miesiac and J. Szymanowski, Colloid Polym. Sci., 76 (1988) 96. P. Mukerjee and K.J. Mysels, Critical Micelle Concentrations of Aqueous Surfactant Systems, Vol. 36, National Bureau of Standard, Washington, DC, 1971. I. Miesigc, H. Merkwitz, J., Szymanowski and J. Beger, J. Colloid Interface Sci., 114 (1986) 425.
363
Hydrophilicity and Critical Micelle Concentration of Polyoxyethylene 4-Alkylphenylamines MACIEJ WISNIEWSKI Technical University of Poznari, Institute of Chemical Technology and Engineering, Sktodowskiej-Curie 2, 60-965 Poznali (Poland) (Received 27 September 1989; accepted 24 January 1990 1
ABSTRACT Surface tension isotherms were determined for polydisperse polyoxyethylene 4-alkylphenylamines. For these products the critical micelle concentration was used to determine the effective length of the hydrophobe in comparison with the standard individual polyoxyethylene glycol monoalkyl ethers. The hydrophobicity increments for the structural fragments of polyoxyethylene 4-alkylphenylamines are equivalent to the following numbers of the methylene groups in the standard polyoxyethylene glycol monoalkyl ethers [CH,]: CH2=0.42 [CH,], Ph-N=0.9 [CH,], Phz4.6 [CH,] andN= -3.7 [CH,].
INTRODUCTION
4-Alkylphenylamines exhibit interesting extraction properties and can be used as group reagents for extraction of noble metals, i.e., gold, palladium, iridium, ruthenium and rhodium [l-lo]. These reagents can be also used as intermediates to obtain other compounds, i.e., (4_alkylphenyl)trimethylammonium halides which, as quaternary salts, also exhibit surface-active and bactericidal properties [ 11-141. Recently, polydisperse polyoxyethylene 4-alkylphenylamines were obtained from 4-alkylphenylamines and ethylene oxide, and their usage, properties and polarity parameters were described [ 15,161. Mass spectrometry-gas chromatography techniques were used to identify the components of these polydisperse products, and gas chromatography was used to determine the contents of the successive homologues with various numbers of oxyethylene units as well as the contents of polyoxyethylene glycols formed as by-products [ 17,181. The aim of this work is to determine the surface tension isotherms and critical micelle concentrations for polydisperse polyoxyethylene 4-alkylphenylamines containing from 1 to 16 carbon atoms in the alkyl group and from 1 to
0166.6622/90/$03.50
0 1990 -
Elsevier Science Publishers B.V.
364 8 average number of oxyethylene units in both oxyethylene chains, and to use these data to estimate the structural increments of hydrophobicity. EXPERIMENTAL
Twenty-two polyoxyethylene 4-alkylphenylamines were used. Their compositions as determined by gas chromatography have been given previously [17]. Surface tension was measured at 20 ° C using the ring method. Solutions were poured into glass vessels 8 cm in diameter and I cm high. The solution surface was carefully sucked off with a capillary tube. The solution was then kept for 24 h and the surface tension was measured. All polyoxyethylene 4-alkylphenylamines containing five and eight oxyethylene groups were well soluble in water. For other amines containing one and three oxyethylene groups methanolic solutions of 1-2 mg cm -3 were first prepared. Then 1 cm 3 of this solution was diluted with redistilled water to 100 cm 3 and used to obtain successively lower concentrations. The critical miceUe concentrations were determined from the surface tension isotherms. The molecular area at the saturated interface was determined from the surface excess calculated according to the Gibbs isotherms: dy Fm~-dlnc
1 1 R T and A = N F~
where N is the Avogadro number, Fm~ the surface excess at the saturated interface, dy/d In c the maximum slope of the surface tension isotherm, R the gas constant and T the absolute temperature. RESULTS AND DISCUSSION Surface tension isotherms obtained for the investigated products are presented in Figs 1-4. The values of the critical miceUe concentrations of the surface excess and of the molecular area are given in Table 1. Lower values of the surface tension at the c.m.c, and lower values of the c.m.c, are obtained for more hydrophobic compounds having a long alkyl group in comparison to hydrophilic compounds having a short alkyl group. The surface excess increases and the molecular area decreases significantly (approximately three times) as the alkyl length increases from the methyl to dodecyl group. The length of the polyoxyethylene groups has a relatively weak effect and only a small decrease of the surface excess and a small increase of the molecular areas are observed as the average degree of ethoxylation increases from I to 8 (approximately 30% ).
365
I
60.
E
5
B
:
'g 50. J 78 e 40. I 30.
3
4
2
-loge
Fig. 1. Surface tension isotherms for polyoxyethylene 4-hexylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation ) .
5
4
3
-
log c
Fig. 2. Surface tension isotherms for polyoxyethylene 4-octylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation).
The c.m.c. also changes in a typical way, i.e. straight-line relations with high and low slopes are obtained as log c.m.c. is correlated with the number of carbon atoms in the alkyl group (m) and the average degree of ethoxylation, respectively. The overall relationship correlating c.m.c. with the number of oxyethylene groups (n) is as follows:
366
J d
z
z 40.
30-
Fig. 3. Surface tension isotherms for polyoxyethylene 4-decylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation).
Fig. 4. Surface tension isotherms for polyoxyethylene 4-dodecylphenylamines for various degrees of ethoxylation (numbers on the curves denote the average degrees of ethoxylation ) .
log c.m.c. = -2.37-0.17m+O.lOri where the constant -2.37 also takes into account the effect of the aromatic ring and the nitrogen atom present in the polyoxyethylene 4-alkylphenylamines, and the c.m.c. is given in mol dmb3. This relationship is statistically valid, as is shown in Table 2 and Fig. 5, although some important deviations are observed. Only one value of the c.m.c.
367 TABLE 1 Parameters characterizing the adsorption of polyoxyethylene 4alkylphenylamines at the air/water interface Alkyl group
Ethoxylation degree
Surface tension at c.m.c. (mN m-‘)
c.m.c. (mm01 dme3)
W-b3 W-b, &OH,, C12H2,
CH3 ‘G&3 GJ-L GoH21 G2H2,
CH3 W-b3 W-L GoH2, G2H2,
CH3 C&I, U-L GoH21 C12H25
Molecular area at the c.m.c. ( 1020m2)
31.7 30.0 28.1 26.8
6.000 0.840 0.314 0.098 0.053
1.32 2.99 3.72 4.72 4.77
125.6 55.5 44.7 35.2 34.8
40.5 32.8 30.6 28.9 17.8
10.500 1.210 0.410 0.210 0.060
1.34 2.84 3.63 4.09 4.49
124.2 58.4 45.8 40.6 37.0
41.5 33.3 32.1 31.0 29.5
11.500 1.585 0.631 0.458 0.066
1.23 2.78 3.28 3.80 4.42
135.2 59.7 50.6 43.7 37.6
42.0 35.3 33.9 32.7 31.5
16.100 2.400 1.149 0.945 0.070
1.13 2.48 2.79 3.73 4.51
146.9
39.0
CH3
Surface excess at the c.m.c. (pm01 m-‘)
67.0 59.5 44.5 36.8
TABLE 2 Statistical assessment for the relation correlating the c.m.c. with the length of the alkyl group and the average degree of ethoxylation Constant
-2.37 -0.17 0.10
Limits for 95% confidence intervals lower
upper
- 2.72 - 0.20 0.05
-2.01 -0.14 0.15
Standard error
Significance level
0.169 0.016 0.024
0.0000 0.0000 0.0008
-,tllllllllll,lllrl,Illllllrlllll -4.4 -3.9 -34 -2.9 -2.4 Predicted
-4.9
-4.4
CMC
Fig. 5. Comparison of the experimental and predicted values of the c.m.c.: ( l ) experimental values; (-) fitted relation; vertical lines denote 95% confidence intervals.
from 20 considered is outside the 95% confidence interval, while the other values of the c.m.c. are near the fitted relation. The values of the c.m.c. can be used to determine the equivalent length of the hydrophobic groups in polyoxyethylene 4alkylphenylamines i.n comparison to polyoxyethylene glycol monoalkyl ethers considered as the standard homologue series. For these last compounds the following relationship was obtained [ 191 using the literature data [ 20,211: logc.m.c.=7.79-0.47m+O.O47(n-6) where m and n denote the number of carbon atoms in the alkyl group and the number of oxyethylene groups, respectively, and the c.m.c. is given in pmol dmW3.Rearranging this equation the following relationship for the length of the alkyl chain can be obtained: m= 15.97+0.X-2.13
log c.m.c.
Introducing into this equation the values of the c.m.c. and average numbers of oxyethylene units, fi, for the polyoxyethylene 4-alkylphenylamines the equivalent length of their hydrophobes (mea) was calculated. This takes into account the length of the alkyl group, the aromatic ring and the nitrogen atom present in the molecules and determines the number of carbon atoms in hypothetical polyoxyethylene glycol monoalkyl ethers having the same c.m.c. as the considered polyoxyethylene amines. The effect of the length of the polyoxyethylene chain upon the determined values of the effective length of the hydrophobe is relatively weak (Table 3) and can be neglected. In this case the simple relationship between both actual
TABLE 3 Effective length of the hydrophohe in polyoxyethylene glycol monoalkyl ethers as the standard compounds )
4-alkylphenylamines
(polyoxyethylene
m
?i=l
ri=3
ri=5
n=8
Average k
1 6 8 10 12
1.63 3.46 4.36 5.44 6.00
1.32 3.31 4.32 4.43 6.10
1.44 3.27 4.12 4.41 6.21
1.42 3.18 3.86
1.5 3.3 4.2 4.7 6.2
6.45
6.
Fig. 6. Effective length of the hydrophobe for polyoxyethylene
t;i
4dkylphenylamines.
y)d effective (meff) alkyl length can be derived with the slope of 0.42 1.
.
meff=0.9+0.42m Thus much lower valuesof the effective lengthof hydrophobesin the polyosyethylene 4alkylphenylamines were obtained in comparison to the chosen standardseries of polyosyethylene glycol monoalkyl ethers. For m=O,meff= 0.9[ CH2]. This means that the CBHbNgroup is equivalent only to approximatelyone methylene group, owing to the strong hydrophilic effect of the nitrogen atom. For (4alkylphenyl) trimethylammoniumhalides the hydrophobiceffect of the aromaticring was previouslyestimatedas equivalent to about 3.3-5.4 methylenegroups [ 111. Thus, if the averagevalue 4.6 is taken then the nitrogen atom in polyosyethylene 4-alkylphenylaminesis equivalentto approximately - 3.7 [ CH,].
370 Similar strong polar effects of the nitrogen atom upon the polarity of various amines containing oligooxyethylene chains were observed using gas chromatography [16]. CONCLUSIONS
The c.m.c, of the polyoxyethylene 4-alkylphenylamines is correlated with the length of the alkyl group (m) and the average degree of ethoxylation (rD according to the following linear equation: log c.m.c. = - 2.37- 0.17m + 0.10~ The nitrogen atom in the considered amines causes a significant increase in the hydrophilicity of polyoxyethylene amines in comparison to the polyoxyethylene glycol monoalkyl ethers taken as standard compounds. The nitrogen atom present in the molecule exhibits a very high hydrophilicity, equivalent to - 3 . 7 [CH2], i.e. methylene groups in the standard polyoxyethylene glycol monoalkyl ethers. As a result the P h - N group is equivalent to only approximately one methylene group. The estimated hydrophobic effects for the structural fragments of polyoxyethylene 4-alkylphenylamines are equivalent to the following numbers of methylene groups in the standard polyoxyethylene glycol monoalkyl ethers, [CH2 ]: CH2 = 0.32 [CH2 ], P h - N = 0.9 [CH 2] Ph ~ 4.6 [CH2 ] N = - 3 . 7 [CH2]. ACKNOWLEDGEMENT This work was supported by Polish Research Program CPBP No 03.08.
REFERENCES I A.A. Vasilyeva, I.G. Yudelevich, I.M. Gindin, T.V. Lanbina, R.S. Shulman, I.L.Kotlarevski and V.N. Andrievsky, Talanta, 22 (1975) 745. 2 C. Pohland, Talanta, 26 (1979) 199. 3 C. Pohland, S.A. Natl. Inst.Metalurgy, Johannesburg, Rept. No. 1991 (1977). 4 C. Pohland, H. Hegetschweiler and T.W. Steele,S.A. Natl. Inst. Metallurgy, Johannesburg, Rept. No. 1940 (1978). 5 B. Weaver, Ion Exchange and Solvent Extraction, Marcel Dekker, New York, 1974. 6 M. Cleare, P. Charlesworth and D.J. Bryson, J. Chem. Tech. Biotechnol.,29 (1979) 210. 7 G.M. Ritcey and A.W. Ashbrook, Solvent Extraction, Part II,Elsevier,Amsterdam, 1979. 8 M. Wi~niewski and J. Szymanowski, Przem. Chem., 65 (1986) 591. 9 A.A. Vasilyeva, V.G. Torgov, N.K. Kalish, L.V. Zelentsova, T.M. Korda, N.V. Maksimova and I.G. Yudelevich, Proc. ISEC 88, Moscow, USSR, Vol. 4, Nauka, Muscow, 1988, p. 100. 10 M. Wi~niewski, Pol. J. Chem., 57 (!983) 593. 11 M. Wi~niwski, J. Colloid Interface Sci.,128 (1989) 115.
371 12 13 14 15 16 17 18 19 20 21
M. Wisniewski, B. Nowak, B. Kedzia and J. Szymanowski, Tenside Deterg., 24 (1986) 46. C.A. Lawrence, Quaternary Ammonium Active Disinfectants, Lea and Febiger, Philadelphia, PA, 1968. M. Wis’niewski and J. Szymanowski, 2nd World Surfactants Congress, Surfactants in our World Today and Tomorrow, ASPA, Paris, France, 1988. M. Wilniewski, Chem. Stosowana, 32 (1988) 503. M. Wisniewski and J. Szymanowski, Colloid Polym. Sci., 59 (1989) 267. M. Wisniewski, J. Szymanowski and B. Atamanczuk, J. Chromatogr., 462 (1989) 39. M. Wibiewski, J. Szymanowski and E. Dziwiriski, Chem. Anal., in press. I. Miesiac and J. Szymanowski, Colloid Polym. Sci., 76 (1988) 96. P. Mukerjee and K.J. Mysels, Critical Micelle Concentrations of Aqueous Surfactant Systems, Vol. 36, National Bureau of Standard, Washington, DC, 1971. I. Miesigc, H. Merkwitz, J., Szymanowski and J. Beger, J. Colloid Interface Sci., 114 (1986) 425.