Ind. Eng. Chem. Prod. Res. Dev. 1980, 19, 447-450
447
Use of Glyphs To Correlate Surfactant Test Data Kenneth J. Lissant" and Guy M. Bradley Tretoliter Division, Petrolite Corporation, St. Louis, Missouri 63 1 19
A series of surfactants, ethylene oxide adducts of ldecanol, were prepared with 2-7 mol of ethylene oxide/mol of decanol and subjected to three physical tests of the type used to screen surfactants for applications. Fifty-six data points, some quantitative and some qualitative, were generated for each sample. Using the technique of glyphs, the data for the entire series could be displayed on a single chart, enabling one to perceive relationships among
the data.
Introduction Workers in industry are constantly faced with the problem of selecting a surface-active agent for use in a product or process. In attempts to provide guides for such selection many screening tests and classification schemes have been proposed. While some of these procedures work well in specific areas, few of them are useful in completely new fields. In an attempt to assess the validity of certain procedures, we had a series of nonionic materials prepared and proceeded to evaluate them on the basis of certain tests. Oxyethylated 1-decanol has never been studied in this fashion. However, oxyethylated dodecanols have been investigated frequently and a few references may be cited to establish the analogy. Mitsui and co-workers included oxyethylated dodecanol in their experimental designs (Mitsui et al., 1966). In general dispersions of liquid paraffin and water were water external and separated after 1 day at room temperature. Results were equivalent for ethylene oxide ratios from 5 to 40. Solubilization has been studied by several groups. In one case (Mitsui and Machida, 19691,dodecanol plus 5 mol of ethylene oxide (C12E5) was an efficient solubilization agent for liquid paraffin in water or for water in liquid paraffin. C12Elowas less effective and favored oil in water systems. C12E3solubilized less than C12E5 and favored neither phase. In another case (Smirnova et al., 1976), heptane solutions of ClzE1,9and C12E5 solubilized water in proportion to ethylene oxide content-approximately 2 mol of water/mol of ethylene oxide-but C12E3,1and C12E4 solubilized larger amounts of water, up to 8 mol of water/mol of ethylene oxide, and the temperature dependence of solubilization was peculiar. In a third case (Harusawa et al., 1974),the system water-dodecaneC12E5 formed exclusively O/ W dispersions at room temperature. Some data on homogeneous oxyethylated 1-decanolsare available (Mulley, 1966). Cloud points of 0.1 70solutions in water are as follows: C10E4,18 "C; C10E5,36 "C; C10E6, 60 "C. Critical micelle concentrations in water at 25 "C are as follows in g/dl,: C10E3,0.017; C10E4, 0.023; C10E5 0.031; c&6, 0.038; c&6,0.072. Aqueous c1&6was found to solubilize 1.5 mol of hexanol/mol of surfactant. Experimental Section A 98% pure grade of 1-decanolis available from Conoco as Alfol 10. This material was reacted with ethylene oxide in a pilot unit using KOH as a catalyst. Seven samples were drawn in the series. The compositions are shown in Table I. The HLB values given in the table were calculated according to the weight percent hydrophilic method (Griffin, 1949) and tlhe group number method (Davies, 1957). 0196-4321/80/1219-0447$01 .OO/O
Solubilities were determined at 1,5,10, and 50% volume in deionized water and in Shellflex 131, a highly saturated, aliphatic hydrocarbon solvent from Shell. Solubilities were run at six temperatures from 25 to 75 "C according to previously described procedures (Lissant, 1963a,b, 1974). Solubilities are recorded in Table 11. The most systematic way to study the surfactants is to determine the phase diagrams or, more properly in the case of mixed systems such as these, the pseudo-ternary diagrams. In fact, we have determined and published the ternary diagrams for these surfactants elsewhere (Lissant and Bradley, 1979). However, phase diagrams require an enormous number of determinations to be at all complete. Often economic or other considerations exclude large sections of the phase diagram from serious consideration for industrial applications. Also, slight variations in the conditions of manufacture may drastically alter the pseudo-ternary diagram of a commercial surfactant. Consequently, arbitrary empirical tests are developed that approximate the use contemplated. We have chosen two tests typical of the types in common use-the oil or water uptake test and the phase preference test. Oil and water uptake tests were run by placing 20 mL of the surfactant solution in a beaker fitted with a splitdisk stirrer and adding gradually either oil or water until phase inversion occurred. Phase inversion was determined by observation of viscosity, appearance, and conductivity. Viscosity and appearance were qualitative judgements based on color, opacity, load on the stirrer motor, and depth of vortex. Conductivity, which is a common test for emulsion type, was determined by immersing the bared, tinned ends of a twin lead in the sample and reading the conductivity on a Particle Charge Tester as described in ASTM test D144-75. Results for l % , lo%, and 20% solutions are given in Table 111. Results are reported as mL added to 20 mL of surfactant solution. In the water uptake tests the oil and surfactant are in the beaker and the water is added gradually. In the oil uptake tests, the phases are reversed. For the phase preference test, 20 mL each of Shellflex 131 and water were placed in 2-02 small-mouthed bottles. Enough surfactant was added to produce 1% or 5% solutions and the bottles were hand shaken. The mixtures were then tested for conductivity, as before, to determine whether the external phase was oil or water. The stability of the dispersions was estimated visually after standing for about 1h. None of the dispersions was stable for over 24 h. The data are given in Table IV. Discussion The first thing that becomes apparent is that we now have accumulated enough data on this series to make it
0 1980 American
Chemical Society
448
Ind. Eng. Chem. Prod. Res. Dev., Vol. 19, No. 3, 1980
Table I. Composition compound designation
A 1.97 7.1 4.8 3-6
mol of ethylene oxide/mol of 1-decanol calculated HLB; HLB = E / 5 group no. HLB - 4.15 * 0.33 E T 0 HLB by solubility
B
C
2.69 8.6 5.0 8-10
3.59 10.0 5.3 10-13
E
D 4.49 11.1 5.6 10-13
F 6.28 12.7 6.2 >13
5.39 12.0 5.9 >13
G 7.18 13.3 6.5 >1 3
Table 11. Solubility compound
25 "C
I S 1
35 "C 5 1 0 50 I I I
1 I
S 1
S 1
S 1
S 1
I S 1
S S S I s I
I I I S s I
I S I S s I
I S I S s I
I S I S s I
I I I S 1 S
1
1
1
1
1
1
solvent
1
5
10 50
1
H,O SF131
I S 1
I S 1
I S 1
S S 1
I I I S s I
I I I I s I
I S I I s I
1
1
1
A
SF131
H,O
C
SF131 H,O SF131 H,O SF131 H,O SF131
D
E F
I S I S 1 S
I s I
1
I
SF131
A
1
1
S s S
I 1 I
I s I
I s I
S
S
I
I
1
S s I
I 1 I
I s I
I s I
S
S
I
I
1
752
B
C
D
E
F
1
5 10 1 1
50 1
I s S
I 1 I
I s I
I s I
I s I
S
S
I
I
S
>20 20 1
>20 10 4
20 7 8
4 6
10 6
4
4
4
75T
G
2 2 > 2 0 >20 > 2 0 > 2 0 8 >20 >20 >20 >20 20 >20 >20 >20 >20 >20 >20 m L of water to inversion
water uptake test 20% 10% 1%
75 "C
1 0 50 1 1
1 0 50 1 1
Table 111. Oil Uptake Test Data m L of oil to inversion oil uptake test 20% 10% 1%
65 "C 5 1
5 1
1
s s s s s s s s s s s s s s I S I I I S I I I S I I I S s s s s s s s s s s s s s s s s s s s s s s s s S S S S S S I I I S I I I s S I I I S I I I S I 1 1 s 1 1 s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s
H,O
G
55 "C
1 0 50 1 1
s s s s s s s s s s s s s s I S I I I I I I I I I I I I s s s s s s s s s s s s s s s s s s s s s s s s
H,O
B
45 "C 5
>20 >20 >20
2 8 4
45.c ~.
nIO%
( 11
50Z
2 11 4 2&,
yb-c
*C
JJ'C
'C
Table IV. Phase Preference Test Results 1%emulsifier
sample
A B C D E F G
5% emulsifier
phase phase mol of prepreEt0 ferred stability ferred stability
2.0 2.1 3.6 4.5 5.4 6.3 7.2
o/w O/W O/W
o/w o/w
O/W O/W
s F P P P
P P
w/o O/W OlW
o/w o/w o/w o/w
S S F P P P
P
difficult to see the general trends. In development work this problem is common. Since the results of the tests are either semiquantitative, qualitative, or Boolean (yes-no), statistical treatments are not applicable. Also, we would like to display the data to take advantage of the human mind's capability of pattern recognition. The method of "glyphs" is suitable, particularly as it permits display of both quantitative and qualitative data a t the same time. We have proceeded to organize the data by the method of glyphs. In this method, suitable symbols are devised for depicting the properties of the members of the series and then these symbols are deployed on an appropriate composition space. In this case, the composition space is a simple one. It consists of a straight line representing the weight of ethylene oxide added to 1-decanol to produce the particular member of the series. The origin is at the far left and a linear scale extends to the right. Seven points
'
35-c 4.5-C
45%
(31
(4)
25 $ (Q
35'C
5s ' C
-. 45-c
(5)
Figure 1. Hexagonal solubility data symbol. (1) Arrow indicates temperature increase. (2) Assignment of concentration sites. (3) Typical example of a compound that is water soluble at low temperatures and kerosene soluble at higher temperatures. (4) Example for depicting water solubility. Small arrow shows glyph modification for no 10% solubility. Large arrow shows glyph modification for no 50% solubility. (5) Example for kerosene. Dots show solubility in kerosene; triangles, water solubility.
along this line represent the seven compounds in our series. These points are at 0.55, 0.75, 1.0, 1.50, 1.75, and 2.0 weights of ethylene oxide per weight of 1-decanol, corresponding to A-G of Table I. Two glyphs are used, one for the solubility data and one for the other tests. The solubility data glyph has been
Ind. Eng. Chem. Prod. Res. Dev., VOI. 19. No. 3, 1980 449 c
L
F
Figure 3. Summary of Tables 11, 111, and IV using glyphs. IO*
Figure 2. Phase preference test.
described in detail elsewhere (Lissant, 1963a,h, 1974). It is explained in Figure 1 which is taken from a patent (Lissant, 1963h). We quote from this patent: "The symbol is based on six equilateral triangles grouped into a hexagon. Each triangle represents one temperature at which solubility was determined. Starting from the upper left hand triangle of the hexagon and proceding counter-clockwise, the triangles represent the solubilities at 25 "C., 35 'C., 45 "C., 55 "C., 65 "C., and 75 OC. Each triangle is further subdivided into four smaller triangles. Each of these four triangles represents a different concentration of the material under test, specifically l % , 5%, 10% and 50%. If the material under test is soluble in water at the specified concentrations, the concentration triangle is drawn in. If not, it is omitted. If the material is soluble in kerosene, a dot is placed in the center of the appropriate concentration triangle. In this manner an unambiguous symbol can be generated for each possible solubility profde. These symhols can then be mapped onto the proper composition space representation using the device of this invention." Since the time when this glyph was devised, two ahbreviations to the symbology have been introduced. If the compound shows full water solubility at a given temperature, a simple open large triangle is suhstituted for the somewhat cluttered, four triangle design. In similar manner, full oil solubility is shown by the arc of a circle in that segment. In this manner, the 48 pieces of solubility data for each member of the series are reduced to one unambiguous glyph. Since this glyph depicts only yes-no data, it is known as a Boolean glyph. The other glyph depicts multivalued, semiquantitative data and is described in Figure 2. Here we have the results of three related tests, the oil uptake test, the water uptake test, and the external phase preference test. Each of the uptake tests is run at three concentrations and the preference test is run at two concentrations. The glyph in Figure 2 consists of two concentric circles divided, radially, into five segments each. The two narrow segments at the top refer to the phase preference test. The left segment depicts the 1% data and the right segment the 5% results. Darkening of the inner circle shows a preference for oilin-water systems, while darkening of the outer circle indicates the preference for water-in-oil systems. Stability of the systems was loosely judged as poor, fair, and good. Poor systems began to separate in less than 5 min; good systems were still intact after 1 h. This is indicated by darkening of one-half, three-fourths, or all of the area. The three wide segments represent the uptake tests at 1%, lo%, and 20% surfactant. The inner circle represents the oil uptake data from Table 111. The stippled area is in proportion to the fraction of 20 mL that is taken up. If more than 20 mL is tolerated, the section is colored in solidly. Similar conventions depict the water uptake test results in the outer circle. In this case each glyph portrays the semiquantitative results of eight separate determinations. This glyph was designed to emphasize the rela-
tionships between the uptake data and the phase preference test data. Nothing is sacred about these particular glyphs or tests. Glyphs may he designed to fit the data they must represent and to serve the purpose intended. Understanding glyph-depicted data does require one to make the effort to become familiar with the range of variations of the glyphs. In Figure 3 are displayed the 392 data from Tables 11, 111, and IV. Consider first the solubility glyphs (snowflakes). Going from left to right, oil solubility begins to decline with compound C , while water solubility is significant only for compounds E-G. Cloud points of 1% solutions in water may be estimated from the glyphs as
