INDUSTRIAL AND ENGINEERING CHEMISTRY
576
Vol. 41, No. 3
They are considered useful and informative but not precise. Table I1 compares the eareful electrometric determinations by Kuentael, Hensley, and Bacon (6) on solutions of distilled water containing 0.1% builder with the present authors' colorimetric determinations a t about 25' C. on 0 0.90 similar solutions. It shows also the colorimetric p H of utheir solutions et the minimum concentration of soap givc ing a permanent suds. Hard water with 0.1% builder gave nearly the same colorimetric value as did distilled water except below a p H of about 11-for example, 0.1% 5 0.16 2 tetrasodium pyrophosphate had a pH of 9.3 in the hard n F! water. Such data should be used with reference to the effect of temperature as shown by Kuentzel et al. and previous articles in their series. 0 le Each series of the suds formation tests except with sodium laurate was run in duplicate on different days. Only the average values are given. A few were run in trip0 09 licate with an intervening period of 4 months. These also check well. The original soap solution consumption, 0.90 without builder, was adjusted so that each builder series would start a t approximately the same value. d w' I n one case two series of determinations were made 3 I< days apart and a second pair 4 months later. The latter 0.16 of the second pair was run with anhydrous metasilicate, 6 and the others with the 5-hydrate. Two points are taken 5 a t random to show the agreement. At 0.1% sodium n 2 metasilicate (NaJ3i03.5H20)the anhydrous soap required 9 0 le to produce permanent suds was 0.162 * 0.003%. The pH was 10.9 with one value 11.0. At 0.5'%, 0.140 * 0.002% soap was used and the pH was 11.3 * 0.2. 0 09 The average differences between duplicate determina0.00 0.04 0.08 0.19 0.16 0.20 tions as indicated by Bolton ( 2 ) seem well within an error ANHYDROUS ALKALI, G. of +=0.005 gram per 100 ml. except in a few cases where Figure 1. M i n i m u m S o d i u m Oleate or S o d i u m S t e a r a t e a n d trouble was found with difficult heavy curds. This is Anhydrous Alkali to Form a Permanent Suds in 100 MI. of about 3% error. H a r d Water a t 98.8" C. All end points were confirmed by addition of a small ex0 Naz0.4.3SiOz 5 = NanO.Z.OSi0z cess of soap solution. With all of the simple soaps few 7 = Naz0.1.OSiOa false end points were noted and with most of the alkalies 8 = Naz0.0.75SiOz 13 = Na4PzOi the end points were easily attained. = Obtained at minimum reaction time of alkali and hard water The data are given in Table I11 on the as-weighed basis and. for better comDarison., are d-o t t e d as anhvdrous alkali DISCUSSION OF TECHNIQUE in the figures. I n these the abscissa is carried out only to about The technique is a modification of the permanent suds method 0.22 gram whereas some of the data in the tables extend to 0.5 of the American Public Health Association and American Water gram. They cover the ordinary washing concentrations. The scale Works Association ( 1 ) and was carried out exactly as described is that which Bolton (8)used except in the case of sodium laurate. by Bolton (8) except that a temperature of 48.8' =t 0.3" C. The identifying number of each alkali is kept the same throughout (120" F.) was used throughout. and does not correspond to Bolton (8). Diagonal lines represent Each final test solution contained 300 p.p;m. (17.5 grains per the curve when the soap itself is used as builder and define the gallon) of hardness as calcium carbonate equivalent and a molecregions in which the alkalies are better or poorer softening agents ular ratio of 2 calcium to 1 magnesium representing many nntthan the soap. This function of soap saving varies with the ural waters. individual soap. The relationship will change somewhat with the Bolton found that the time element had little effect. The basis on which the builder content is plotted-anhydrous, sodium builder is added to the hard water and allowed to warm up to oxide content, etc. The curves have sometimes been smoothed 48.8' C. in a water bath and end points obtained in 15 minutes out as, particularly with complex phosphates, there is a series of agree with those at 30 minutes. However, it has been found repronounced inflections for which we have no adequate explanacently that in the case of sodium oleate if the hard water is tion, but they do not affect the relative values. warmed up before the builder solution is added and the reaction time before soap addition is thus cut from about 5 minutes to about 1 minute, there is a definite increase in the sodium oleate required. TABLE11. ELECTROMETRIC ( 6 ) AND COLORIMETRIC pH O B SOLUTIONS These curves are shown by broken lines in Figure OF DISTILLED WATERAND 0.1% BUILDER 1. The relative position, however, seems essen(Compared with the colorimetric pH of solutions containing 0.1% builder and sufficient soap to form a permanent suds) hially unchanged. This finding indicates the need Electro- ColoriPalmi- Myrisfor a study of equilibrium when alkali and soap Builder metric (6) metric Stearate Oleate tate tate Laurate Kettle are added together or in the reverse order. NaaSi0!.5HaO 11.6 11.6 11.4 11.2 11.0 10.8 .. 10.9 After the end point was reached p H values were 11.8 ll.* 11.5 '. 11.3 11.2 12.3 12.1 .. .. 11.9 11.8 ii:7 11.6 determined a t room temperature by the coloriNa304.12HzO 11.3 .11.1 10.9 10.3 10.6 NaaPa07 10.0 10.1 9:s 9:6 9.8 9.0 8:9 9.5 metric method using parazo-orange, acyl red, NazCOt 10.9 10.7 .. .. 10.8 10.5 10.5 10.6 and phthalein red in a Taylor slide comparator. 0.94
8
P
~~~2°4.5H10
ilicate EFFECT OF SINGLE SOAPS AND FORMATION IN
ERS ON SUDS
CHARLES H. DEDRICK AND JOHN H. WILLS Philadelphia Quarts Company, Philudelphia, P a .
and the commercial kettle soap by courtesy of Lever Brws Company. The analyses supplied are given in Table I. The kettle soap was cut up and stored in the dark in sealed glass jars. Sodium soaps were prepared by dissolving 100 grams of the fatty acid in methanol and neutralizing with the calculated amount of sodium hydroxide dissolved in methanol. A dry soap powder was formcd by carefully evaporating the alcohol and finally drying in an oven at 105 to 110' C. Further drying of smaller samples to constant weight indicated a moisture content, in the soap as used, of 1.01% of the sodium laurate, 0.40% of the sodium myristate, and 120% of the sodium palmitate. All dissolved to a clear solution in hot water and alcohol solutions were alkaline to phenolphthalein. The first stock of each 1%soap solution was tested against the synthetic hard water used in the experimental work and all subsequent stock solutions were adjusted to the same value a t least once a day. The stock solution was usiially stable for a t least 4 days and only occasionally was it found necessary to adjust its value. The pH values were determined colorimetrically a t 80" t o 40" C, using acyl red and phthalein red in a Taylor slide comparator after the solutions had aged a t least 7 hours a t 48.8" C . Acyl red gave a value of 10.7 with sodium stearate and 10.5 with sodium oleate although no reading was obtainable sometimes. No reading could be obtained with acyl red on the other 1% soap solutions. With phthalein red the following values were found:
Data showing the influence of various alkalies on the decrease in soap required to form a permanent suds in hard water were reported by Bolton (2) for sodium oleate a t 20" C. and stearate at 60" C, This work has been extended to cover sodium myristate, laurate, palmitate, and a commercial kettle soap at 48.8' C. Reduction in the amount of the latter required to form a permanent suds under the conditions described is thought to be predictable from a knowledge of the behavior of the individual soaps.
I
(4,1 0 ) suggested the incorporation of sodium silicate in soap and over 80 years since Elkinton started his experiments on the production of water glass in his small soap factory (8). During most of this time it has been recognized that builders have not only maintained the cost of soap a t a reasonably low level in war and peace but have added specific benefits to the stability, attractiveness, and detergent performance of this commonplace necessity of civilization. However, there have been d a t i v e l y little data on the interreaction of builders and the individual soaps which go into our common soap, Bolton's (6)comparison of the reduced consumption of sodium stearate and sodium oleate by hard water following the addition of builders elicited the interest of soap manufacturers, and the authors were encouraged to extend the work to cover most of the component soaps of a commercial kettle soap at about 50" C. T IS now about a hundred years since von Puchs
Sodium oleate Sodium stearate Sodium palmitate Sodium laurate Sodium myristate Kettle soap
8 hr.
1 day
2 daya
4 day?.
9.7 9.3 8.9 8.7 8.7 8.8
9.7 0.3
9.7 9.3
8.5
...
... .."
8:i
s:i
a:a
..
9,s
~ . .
iMATERIhES
The sodium stearate and sodium oleate described by Rolton ( 2 ) and palmitic acid from Eastman Kodak Company were used. Lauric acid (Neo-Fat No. 11) and myristic acid (Seo-Fat KO. 13) were obtained by courtesy of Armour & Company in June 1940
TABLEI. COMPOSITIOXS SUPPLIED BY MAXGFACTURERS Eoap Composition Chemical formula
Kettle SoapQ
Yeo-Fat
....
....
l l b
Fatty acids 63.65 . . . Mean molecular weight .., 203.0 Melting point, C. .... 37.8 Titer 37.5 .... Iodine value 42.5 1.0 Neutralization value 2 1 7 . 5 27G.0 Unsaponifiables 0.4 Moisture (105O C.) 29:53 , . , . Color White White ., . . Trace Odor Pounds/C. S. gal. . . . . . 7.25 Fatty acid aomposition 1.0 .... Ca caprylic, % Trace 0.7 CIOcapric, % 9.6 90.0 CIZlauric % 6.5 9.0 Cl4 myrislic, % .... 2.9 C1a-2H pa!mitoleic, % 24.8 .... Cla palmitic yo 3.5 Cta-4H paliktic, % 38.4 .... Cla-2H oleic, % 12.8 .... CISstearic, % .... 1. 0 Unsaturated, % a Supplied by Lever Bros. Company. b Supplied by Srmour & Coompany.
.
, I . .
Lauric Neo-Fat Nyristic Acid 13b Acid CiiHw . . . . CI3HI7COOH COOH
....
....
....
200.19 43.6
226.0 51.0
228.22 53.8
Xone 280.0
2.0 248.0 0.02
24fi.l
....
Xone , . . ,
....
....
White Trace
White Slight 7.5
....
.. .. .. ..
4.0 90.0
....
....
....
....
.... .... ,
.
I
.
....
hIateria1 Sodium tetrasilicate (1 I ) S (sodium silicate) N (sodium silicate) 1: (sodium silicate) L (sodium silicatc) C lsodjum s/l/cate) B sodium silicate) Metso (sodium metasilicate) Metso 99 (sodium sesquisilicate) Caustic soda (sodium hydroxide) Borax (sodium tetraborate) Soda ash (sodium carbonate) Trisodium phosphate Tetrasodium pyrophosphate Sodium tetraphosphate Calgon (sodium hexametaphosphate)
Sone None
....
White Trace
. , ..
....
....
4.0
.... .... 2.0
The synthetic hard n-uter had a pH of about 6.8. For use a t 4t.8" C. the 170 stock solution of sodium palmitate was held a t 80 * 2" C, and that of sodium stearate was held a t 60' C. The commercial kettle soap and sodium myristate soiutions were held a t 48.8" C. while determinations were being made. The other stock solutions (also 1%) were held at room temperature. Crystalline sodium tetrasilicate was used in addition to Bolton's list (3). This salt has a low solubility and was used a~ B slurry with a pH of about 10. Except in the sodium myristate series, the Calyon was the "adjusted" product containing a small amount of sodium carbonate and sodium bicarbonate. This additive increases the pH of a 0,5% solution from about 6.9 for the unadjusted to about 8.5 for the adjusted product (6).
. . I .
... .... ....
....
Composition 3S7a20.13SiOz. 1IHz0 NazO.3.9SiOn (30.97 soin.) NapO.3.2SiOz (37.13% soln.) NatO .2.SSiOn (42.9% soln.) N a 2 0 . 2.4SiOz NazO, 2 . 0 S j O ~(46.9% ( 5 4 . 0 7 soin.) soh) ?jazo. 1.6~t0z ( 6 2 . 9 d soln.) KazSiOa, .5Hz0 NanHSiOl. 51320 KaOH (c.P.) NanBaOi. 1013~0 NanCOs NaaPO4.12HxO XarhOi NasPiOia (NaP0a)e
..
Stock solutions of each of these materials were made up and stored except for the three complex hosphate solutions which were freshly prepared each day as neefed.
575
\
INDUSTRIAL AND ENGINEERING CHEMISTRY
March 1949
577
SOAP REQUIRED FOR PERMANENT SUDS IN 100 ML. OF HARD WATER' COLORIMETER p H VALUESO F RESULTING SOLUTIONS AT ROOM TEMPBRATURE
TABLE 111. AND
Soap
0.00 g.
(Hard water contains fixed amount of alkali a t 48.8' C.) pH Values a t Alkali Concentration of Gramsf Soap at Alkali Concentration of 0.00 g. 0.01 g. 0.03 g.O.05g.O.lOg.O.20 g. 0.30 g . O . 5 O C 0.01 g. 0.03 g. 0.05g. 0.10 6. 0.20 g. 0.30g. 0.50 g.'
Sodium oleate 3Naz0.13Si0z.llHzO NazSiOa .5Hn0 NasHSi0~.5IIzo NaaPaOi
0.235 0.230 0.230 0.231
0.236 0.230 0.222 0.228 0.193 0.169 0.224 0.185 0.164 0.197 0.170 0.153
Sodium oleate (at minimum reaction time) NazSiOa. 5HzO Naz0.2.09iOz (54% soln.) NarPzO7
0.236 0.236 0.236
0.250
Sodium stearate 3Na~0.13SiOz.llH~O NazSiOs. 5Hz0 NasHSiOa. 5Hz0 Na4Pz07
0,208 0.205 0.200 0.205
0.210 0.195 0.195 0.200
0.182 0.182 0,182 0.182 0.182 0.182 0.182 0.183 0.182 0.182 0,182 0.182 0.182 0.182 0.182 0.182
0.176 0.173 0.174 0.172 0,172 0.170 0.175 0.172 0.166 0.174 0.164 0.170 0.176 0.173 0,173 0.176
0.152 0.153 0.153 0.153 0.153 0.154 0.153 0.152 0.154 0.153 0.153 0.153 0.153 0.153 0.155 0.153
0.168 0.178 0.180 0.168 0.165 0.163 0.159 0 , 1 8 1 0.154 0.174 0.176 0.196 0.161 0 , 1 9 8 0.169 0 , 1 9 8 0.177 0.201 0.190 0.201 0.161 0.185 0.170 0.160 0.159 0.166 0.153 0.144 0.143 0.151 0.153 0.135
0 13 0'108 0.109 0.108 0 108 0 108 0 107 0:lOS 0.107 0.107
Sodium palmitate NazO .3.9SiOa (30.9% soln.) Naz0.3.2SiOz (37.6 soln.) Nan0 .2.9SiOz (42.9% s o h ) Naz0.2.4SiOz (46.9% s o h ) Naz0.2.OSiOz (54.0% s o h ) Nan?. 1.6Sioz (62.9% s o h ) NazSiOa. 5H20 NasHSiOa.513~0 NaOH NazB407. lOHzO NazCO3 NaaPO4.12Hn0 NaaPnOr NasP4Ol~ (NaPOa)a (adjusted)
(NaPOs)s
Sodium myristate 3NazO. 13SiOz.llHzC I NazO.3.9SiOz (30.9% soln.) Naz0.3.2SiOz (37.6% soln.) Na20.2.9Si02 (42.9% s o h ) Naz0.2.4SiOn (46 9 7 s o h ) Nas0.2.0SiOz (54:Og soln.) Nan0.1.6SiOz (62.9% s o h ) NazSiOs. 5 H n 0 WaaHSiOa. 5Hz0 NaOH Na~B40,.10HzO NazCOa Nad'Od. 12Hz0 N~IPzOI NasP40~ (NaP0a)s Sodium laurate 3Naz0.13Sioz. llHzO NazO,.3.9SiOz (30.9% s o h ) NaaSiOs, 5 1 3 ~ 0 NaOH NazBaO7.lOHzO NazCOs NaaPOa. 12H20 NarPzO7 NasPaOlr
(NaPOde Kettle soap
0.209 0.204 0.192 0.166 0.167 0.165 0.167 0.167 0.166 0.144 0.129 0.114
0.186 0.164 0.163 0.057
8.6 8.5 8.5 8.6
9.1 9.9 10.2 8.8
0.185
9.8 9.3 8.8
0.216 0.247 0.182
0,182 0.175 0.242 0.218 0.161 0.156
o:i& o : i h o:oiz
8 5 8.3 8.5
0.206
0,176 0.181 0.199
0.204 0.158 0.168 0.182
0.194 0.143 0.142 0.159
0.188 0.134 0.126 0.125
0.184 0.129 0,121 0.122
0.178 0.119 0.113 0.121
8.7 8.6 8.9 8.6
9.1 10.2 10.6 9.1
0.173 0.167 0.167 0.168 0.163 0.162 0.160 0.152 0.143 0.170 0.105 0.167 0.165 0.161 0.166 0.188
0.171 0.164 0.160 0.158 0.155 0.153 0.144 '0.138 0.105 0.168 0,098 0.165 0.161 0.148 0.156 0.209
0,163 0.157 0.152 0.148 0.142 0.139 0.125 0.110 0.103 0.168
0.159 0.151 0.146 0.131 0,123 0.130 0.118 0.108 0.103 0.167 0.088 0.087 0,165 0.165 0 . I48 0.105 0.117 0.131 0.123 0.133 0.195 0.306
0.164 0,142 0.130 0,120 0.106 0.118 0.110 0.106 0.102 0.167 0.085 0.167 0.107 0.157 0.160 0.339
0.151 0.132 0.119 0.107 0,095 0.106 0.109 0.105 0.102 0,163 0.085 0.167 0.106 0.171 0.196 0.194
8.7 8.8 8.8 8.8 9 .o 8.8 8.7 8.6 9.0 9.0 8.7 9 0 8.9 8.7 8.6 8.7
8.9 9.0 9.2 9.1 9.4 9.4 9.8 10.1 10.6 9.0 9.4 9.7 9.2
0,180 0.175 0.157 0 130 0.111 0.110 0.108 0.104 0,101 0.099 0.167 0.088 0.173 0.098 0.004 0.002
6.1 6.4 6.4 6.3 6.4 6.5 6.4 6.4 6.4 6.4 6.3 6.3 6.4 6.4 6.4 6.3
6.7 6.9 6.6 6.6 6.6 7.4 7.1 7.5 6.4 10.1 7.2 8.3 6.9 6.9 6.6 6.8
0 212 0:165 0:%7 0 : 3 h 0:400 0:528 1:: 0.412 0.476 0.710 0.571 0 '35'6 o :iii 0.311 0:iOO 01380 0:350 0.320 0 382 0.511 0.444 0.384 0.360 0 193 0:266 0 538 0:iiz 0:156 0.187 0:312 0:360 0.336 0:276 0:204 0.113 0.113 0.103 0.124 0.133 0.132 0.010 0.111 0.116 0.104 0.084 0.010 0.007 0.007
6.5 6.3 6.3 6.3 6.3 6.3 6.3 6.4 6.3 6.3
7.1 6.9 8.7 10.3 7.9 8.4 7.3 7.1 6.5 6.5
0.218 0.149 0.150 0.140 0.124 0.134 0.134 0.141 0.147 0.131 0.230 0.063 0.103 0.050 0.097 0.006
8.4 8.6 8.6 8.6 8.6 8.6 8.6 8.9 8.9 8.6 8.6 8.6 8.6 8.7 8.5 8.7
s:9 8.8 8.8 9.1 9.2 9.4 10.0 10.1 10.7 8.7 9.4 8.6 8.9 8.6 8.5
0.240
0.211
0.178
0.182
0.196 0.203 0,201 0'. 209 0.201 0.203 0.196 0.158 0.150 0.116 0.182 0.129 0.198 0.103 0.093 0.086
... ... ,.,
...
...
3NazO.13Hz0.11Hz0 Naa0.3.QSiOz 30 9 s o h ) NaaO .3.2S/01 {37:62 s o h ) NarO 2 9910r (42 9 7 aoln.) Naz0:2:4SiOz (46:Q.P soln.) NarO.Z.OS/Oz 54 0 soln NasO,. 1.6SlOr {62& 8Olll:l NarSiOt . 5 H t 0 NasHSiO4.5Hz~ NaOH Na~B407.10HaO NasCOa NaaPOi. 12HaO NarPzOt NaaP40~
(NaPOh
...
:::
8.8
8.7 8.4
9.3 10.2 10.6 9.0
9.5 9.3 10.5 11.0 1 0 . 8 11.1 9.6 9.2
9 . 5 9.6 9.5 1 1 . 3 11.4 11.5 11.5 1 1 . 8 11.9 1 0 . 2 1 0 . 1 10.2
1 0 , 7 10.7 9.7 9.7 9.4 9.1
11.2 10.2 9.6
11.3
11.7
11.9
1O:O
l0:3
10:4
9.2 10.7 10.9 9.4
9.3 10.9 11.2 9.6
9.4 11.4 11.5 9.8
9.5 11.7 11.9 10.0
11.9 12.0 10.0
9.6
9.6 12.0 12.1 10.1
9.1 9.3 9.4 9.4 9.7 10.3 10.3 10.6 11.1 9.0 10.1 10.3 9,3 8.6 8.8 8.3
9.3 9.5 9.7 9.7 10.1 10.4 10.7 11.0 11.3 9.0 10.3 10.5 9.5 8.4 8.4 8.2
9.6 9 . 78
9.9 10.0 10.2
1 0 . 1 10.2
10.1 10.4 10.7 11.0 11.4 11.9 9.0 10.8 10.9 9.8 88.1 .3
10.2 10.6 10.9 11.3 11.9 12.0 8.9 10.7 11.2 9.8 8 . 43
7.4
7.9 7.2 7.7 8.0 8.4 8.7 9.3 9.5 10.2 11.3 8.3 9.5 7.7 7.8 7.2 7.0
8:1
.. .. ..
7:7 7.7 6.7 6.7 9:2 9.2 9.1 9.7 9.8
1o:o
10.1 10.5 11.1 8.8 10.1 9.4 9.0 7.7 7.9
7.6
10.1 10.3 10.3 10.6 11.1 11.3 11.9 12.0 9.0 10.8 11.3 10.1 8.5 8.3 7.4
10.3 10 4 10.4 10.7 11.3 11.8 12.1 12.2 9.0 11.0 11.3 10.1 8.5 8.3 6.9
9.2 8.8 9.1 9.2 8.5 8.7 9.4 9 . 3 10.0 9 . 6 10.1 10.2 10.8 10.7 11.3 11.5 11.8 8.7 8.6 10.1 1 0 . 5 8.5 10.3 8.1 9.0 7.3 7.2 6.9 6.9
9.3 9.4 9.7 9.7 9.8 10.2 10.7 11.3 11.6 11.9 8.9 10.7 10.9 9.5 7.8 7.3
9.3 9.7 10.0 10.1 10.2 10.5 10.9 11.5 11.8 12.2 9 .o 10.8 11.1 9.7 7.8 7.3
9.3 10.3 10.3 10.3 10.5 10.6 11.1 11.8 12.0 12.3 9 0 10.9 11.3 9.8 7.9 7.4
9:1
.. ..
..
9:4
8.3 8.0
8.8
i:7 9.9
ii:7 a:5 8.9 10.1 10.5 8.7 8.1 i : 9 7.3 6.8 7.0 6.8
9:3
9.3 9.2 9.9 10.1 10.1 10.4 10.7 11.4 8.9 10.3 9.7 9.3 7.6 7.6
9:4 9.5 9.5 10.4 10.3 10.5 10.9 11.2 11.8 8.9 10.6 10.6 9.5 7.6 7.3
11.1
.. ..
10: 9 9.3 7.7 7.1 9.4 9.7 9.7 10.1 10.5 10.5 10.8 11.1 11.3 11.9 8.9 10.8 10.9 9.9 7.8 7.5
..
..
10.7
12:1 9.0 10.9
916 7.8 7.3
917 8.0 7.4
i:0
9.5 9.5 10.1 10.3 10.1 10.2 10.2 10.4 LO.5 10.8 10.6 10.7 10.9 1 1 . 2 11.3 11.2 11.3 11.3 11.9 1 2 . 1 9 .o 9.0 10.8 10.9 11.2 1 1 . 3 10.1 10.4 8.3 8.3 7.7 7.7
Equivalent t o 300 p.p.m. calcium aarbonate. I
SODIUM OLEATE AND STEARATE
A few representative curves have been determined for sodium oleate and sodium stearate at this temperature of 48.8' C. (Figure 1). A comparison (Table IV) with the data of Bolton (2) shows only a little difference. The alkaline silicates and tetrasodium pyrophosphate tend t o be slightly less efficient in reducing the soap needed t o form suds with sodium stearate at 48.8" C. than at 60" C. but t h e differences are usually of the order of the experimental error. All three alkalies were somewhat less efficient with sodium oleate at 48.8"C. than at 20" C. Tetra-
sodium pyrophosphate except at 0.5-gram concentration showed differences hardly greater than experimental error. The silicates showed differences of from 0.01 t o 0.04 as the concentration of the builder increased. Ruff ( 9 ) has found no significant change for coconut oil and tallow soaps up t o 125' F. with a hardness of 50 p.p.m. calcium chloride as calcium carbonate. Only the alkaline silicates at 48.8' C. are really more efficient softeners than both of the soaps, but tetrasodium pyrophosphate is better than sodium oleate.
,
INDUSTRIAL AND ENGINEERING CHEMISTRY
578 0.90
Vol. 41, No. 3
Soda ash was very irregular and uncertain in its effects and values were hard to obtain. Quadruple determinations varied greatly. In this respect soda ash differed materially from the other alkalies ivhich usually reacted with the water and soaps to give concordant results. The end points with the soda ash were good enough when obtained but the reaction of the soap and ivater was not always the same and this influenced soap consumption.
0.16
0.12
SODIUM MYRISTATE
With sodium myristate (Figure 3) the alkalies were considerably more effective than they were with sodium laurate but none was a more efficient softener than the soap. At concentrations used for washing, the commercial crystalline silicates, caustic soda, and soda ash Fere effective in reducing the soap needed to form suds. Again the silicates a t about I to 2 ratio are out of order-Le., the soap needed to form suds decreases with the following series of ratios of silicon dioxide to sodium oxide, 3.9, 3.2, 2.9 = 1.6, 2.0, 2.4, 1.0, 0.76, 0. The polyphosphates were very effective almost from the initial concentrations, especially Calgon and sodium tetraphosphrtte. These latter builders exhibit a very sharp drop a t concentrations greater than those normally used for washing. Tetrasodium pyrophosphate soap consumption levcled off and occupied a position between the commercial crystalline silicates and the polyphosphates. The suds produced by the myristate soap mere good as a whole, as were the end points. The suds were not as heavy and strong as those produced by the higher molecular weight soaps but they were good and satisfactorv and there was little or no curding out of the soap.
d 0.08
PI
$
0.04
0.00
0.24
1
-1
0.08 0.19 ANHYDROUS SILICATE, G .
I
I
I 0.04
I 0.08
0.16
I
I
1 0.12
I 0.16
0 20
I
I
I
I
d
I
1
0.20 m
0.16
0.12
0.08 1 0.00
\
0.QO
ANHYDROUS ALKALI, G .
Figure 2. Minimum Sodium Palmitate and Anhydrous Silicate or A4nhydrousAlkali to Form Permanent Suds in 100 M1. of Hard Water at 48.8" C. 1 2 3 4 5 6 7
= Na20.3.96/0~
-
Naz0.3.3610~ Naz0.2.9SiOz Naz0.2.4SiOz = h'az0.2.OSiOz = Naz0.1.6SiOz Naz0.1.OSiOz 8 = Naz0.0.75SiOz = =
9 = NaOH 10 = iiazBIO7 11 = i%aaCOa 12 = NaaPOa 13 = KaaPzOi 14 = NatPdOis 15 = (SaPOde adj. 16 = (NaPO8)aunadj.
It is perhaps significant to note t h a t in Figure 1 the broken lines corresponding to a minimum reaction time for the alkaline silicates show a definite maximum a t concentrations well below the washing range. SODIUM PALMITATE
With sodium palmitate (Figure 2) all of the alkalies except unadjusted Calgon reduced soap consumption below t,he requirements of the hard water blank. However, only caustic soda, soda ash, and the alkaline silicates were more efficient than the soap as softening agents. The 1 to 2.0 ratio falls out of line in the series of increasing alkalinity of sodium silicate solutions. The effect of the most alkaline builqers was pronounced a t low concentrations, reaching a minimum soap consumption, and then almost leveling off. Surprisingly, tetrasodium pyrophosphate reduced soap consumption only a little a t its low concentrations but after passing the concentration of alkalies usually associated with laundry work i t became as efficient, as the commercial crystalline silicates. Calgon was approximately equivalent to the sodium tetraphosphate. After passing the minimum, soap required for permanent suds rose rapidly and became greater than that, of the blank. The more acidic unadjusted Calgon required more soap than the blank over the normal washing range but a t higher concentrations the curve drops off again.
SODIUM LkURATE
The sodium laurate (Figure 3) needed to form suds was greatly increased by all the alkalies used to treat the hard water before the addition of soap with the exception of Calgon and sodium tetraphosphate and none were more efficient softeners. The suds produced with sodium laurate in the alkalitreated hard water usually were good. The suds were not heavy or creamy but they were persistent and continuous. Only rarely were curds formed with the alkalies and then only a t the highest concentrations. These suds were not of the texture usually associated with laundry work but laundry work is not conducted a t so low a pH. Experimental work with sodium laurate was not conducted over the entire roster of detergents and only in two series (Calgon and sodium tetraphosphate) were runs made in duplicate. As
TABLE IV. EFFECT OF TEMPERATURE as SHOWN BY COIIPARISON WITH BOLTOX'S DATA Soap and Alkali Sodium oleate NazSiOa.5HzO NasHSiOi.5HzO NarPzOi
Sodium stearate NazSiOa.5HzO liaaHSiOi.SHa0
NaaPzOi
Temperature,
C.
20
Grams of Soap a t Alkali Concentration of 0.00 g. 0.03 g. 0.05 6. 0.10 g. 0.30 g. 0.50 g. 0.232 0.230
0,180
48.8 20 48.8 20 48.8
0.232 0.160 0,230 0 , 1 8 5 0 . 2 2 8 0.168 0.231 0.170
48.8 60 48.8 60 48.8 60
0,205 0.209 0.205 0.207 0,205 0.205
0.193
0.176 0.168 0.181 0.170 0.199 0.197
0.131 0,128 0.166 0.165 0.164 0.140 0.125 0.126 0.187 0.186 0.163 0.133 0 . 1 1 3 0.101 0 . 1 6 3 0.144 0.114 0.057 0.164 0.169
0.144
0.144 0.184 0.144
0.143 0 . 1 2 9 0.119 0 . 1 4 0 0.128 0.129 0 , 1 4 2 0.121 0.113 0 , 1 3 7 0.122 0.120 0.159 0 . 1 2 2 0 . 1 2 1 0.175 0,130 0 . 1 2 2 0,122
0.158 0.132 0.168 0.158 0.182
INDUSTRIAL A N D ENGINEERING CHEMISTRY
March 1949
in the sodium myristate series, these two dropped to extremely low values at the highest concentration. The amount of soap needed for the others was high and the dilution greatly affected the accuracy, as no correction was made for added volume. KETTLE
0.90
0.16
SOAP
All the builders except borax and the most siliceous silicates were more efficient water softeners than the kettle soap over some concentration ranges and were closely bunched in the range recommended for washing (Figure 4). Calgon again showed a sharp drop at concentrations above the normal washing range. It is again interesting to note that the effectiveness of the silicates in decreasing the kettle soap needed to form suds increases regularly, except for U (2.4), in the following order of ratios of silicon dioxide to sodium oxide: 3.9, 3.3, 2.9, 2.0 = 1.6, 1.0 = 0.75, 2.4, 0.
579
0.lQ
d u i
c
5a
f
0 08
3 0.90
0.00
0.04
0.08
0.19
0 16
0.20
ANHYDROUS SILICATE, G.
B
G E N E R A L R E LATION SHIPS
The appearance of the suds changed with the sodium content or molecular weight of the soap and with the 0.16 alkali. Actual differences are, of course, difficult to define but the density of the suds increased with the molecular weight. The alkalies generally gave good tenacious suds but borax gave practically none. In some cases trisodium 0.19 phosphate gave coarse metallic suds. Soda ash tended t o form a light film on the glass surface. The minimum soap required to form a permanent suds in untreated hard water w w in the order laurate, myris0 08 tate, palmitate, stearate, and oleate. Since the oleate had a titratable alkali of 7.18% instead of the theoretical 7.57%, the order follows the alkali content and not, the molecular weight. More strictly it probably depends on the hydroxyl ion concentration, as Miles and Ross ( 7 ) have found p H a controlling factor in foam height. They also concluded that one calcium ion reacted with two acid radicals. The authors’ results do not indicate a stoichiometric reaction and thus agree with Ruff (9)who studied the water softening characteristics of tallow soap in water at 50 p.p.m. hardness which varied from 100% calcium to 100% magnesium. His method was similar to theirs and he found that 37Yo excess over that calculated was required for calcium hardness and 55% for magnesium hardness. Since Miles and Ross worked at an optimum p H and a maximum suds stability it, is reasonable to expect a different result. I n the authors’ work 25% less sodium laurate appeared t o react than was calculated from the alkali content where0 00 0 04 0 08 0.19 0.16 0 eo as 3y0 more sodium myristate, 10% more sodium palmiANHYDROUS ALKALI, G. tate, 14% more sodium stearate, and 25% more sodium Figure 3. Minimum Sodium Myristate or Sodium Laurate oleate appeared to react. and Anhydrous Silicate or Anhydrous Alkali to Form PermaI n hard water treated with alkaline silicates, soda ash, nent Suds in 100 MI. of Hard Water at 48.8’ C. and caustic soda a rather sharp change of dope occurs in 8 Naz0.0.75SiO~ 9 the systems with sodium oleate and sodium palmitate at NaOH 10 NazB401 approximately stoichiometric proportions of alkali and 11 NazCOa 12 NssPOa hardness-i.e., 18.6 mg. of sodium oxide and 30 mg. of 13 NaaP& 14 hardness. The siliceous silicates do not show such a sharp NasP4Oir 15 (XaP0a)s change and when it occurs with the polyphosphates it does - = Normal scale not necessarily have any stoichiometric relation. The tendency for the builder curves to flattenout supports the general commercial practice of using about 0.1 to 0.2%anhyof small consequence. They used a “well-known medium titer drous builder in washing processes. This is apparently the most soap” of composition unknown to Dedrick and Wills. Because economical range and accomplishes the cleaning with a minimum these authors believe t h a t 0.1% builder is often used, even in hard water, Table V has been prepared showing their results at 0.1% of physical or chemical effect on the fibers. The useful paper by Cobbs, Harris, and Eok ( 3 )gives data on soil removal which may anhydrous builder for the following: soil removal at two soap be compared, with some reservations. Their water of 300 p.p.m. contents, foam height, and the minimum soap content for 5hardness had a ratio of 3 calcium t o 2 magnesium. It contained minute suds. The p H values, except for trisodium phosphate, both chlorine and sulfate salts which Bolton (2)showed to be agree very well.
580
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 41, No. 3
According t o Cobbs et al. ( 3 ) maximum carbon soil removal, usually about 6570, occurs a t less than 0.1% anhydrous builder in nearly all cases. Tet,rasodium pyrophosphate and sodium silicate (Naz0.2Si02) have a broad peak. For maximum soil removal, additional soap over that required for 5-minut,e suds is required but there seems to be no correlation between foam height and soil removal. rllthough Cobbs et al. (3) added their detergent misture all a t once, t,heir data on foam height show reasonatile agreement in the minimum soap required to form suds. The commercial practice of using mixtures of polyphosphates and sodium silicates is in part explained by the authors’ finding that t,he silicates gave the best results with the high molecular weight soaps and the polyphosphates were outstandingly effective with those of low molecular weight.
0.24
0.90
0.16
0.12 l.5
2
ADDITIVE EFFECT OF SOAPS
93 0.09 0.00
0.04
5
0.08 0.19 ANHYDROUS SILICATE, G.
0.16
0.90
Y
0.24
,
r- ,
0.90
0.16
0.19
1 1
There seems to be considerable difference of opinion on the additive effect of the consumption of soaps in mixtures. For a system involving the formation of a minimum amount of suds it seems only reasonable that the. amount of a mixed soap required to form suds can be calculated if the amount required for each individual soap i;i knomm, for a t a condition of minimum suds there will bc little chance of reconversion. Ruff (9) mixed a tallow soap and a rosin soap in known amounts and obtaiiwtl agreement of better than 4 or 5% up t o betxeen 70 anti 80% rosin for his calculated and determined values. Hv concluded: “The water softening propert,ies of mistxl sodium tallow soap and sodium rosin soap are additive at levels of rosin in the stock below roughly 70%.” Dedrick and Wills’ data seem to bear this out but they involvcx too many sources of error to be conclusive.
I n the first place, the untested minor const,ituentu makc up 8.1% of the total fatty acid present. Of these 6.4% 0.09 were unsaturated soaps. Their average reduction was assumed to be 0.170 which is slightly greater than that ot‘ ANHYDROUS ALKALI, G. the oleate. Saturated soaps, 1.’7%, had fewer carbon atoms than lawate and t’he consumption is assumed to be Figure 4 , ~ ~ i n i m ucommercial m lcettlc soapand Anhydrous 0.70 which is a little higher. Further, the lauric and Silicate or Anhydrous to Form Permanent suds in 100 myristic acids had appreciable impurities. The sodium MI. of Hard Water at 48.8’ C. stearate U.S.P. undoubtedly contained sodium palmi8 = Naz0.0.75SiOn tate, These two soaps are close homologs and, except fur 0 Naz0.4.3SiOz 9 = XaOH 1 = Naz0.3.9SiOz sodium carbonate, give nearly the same reaction values. 10 = NaZB407 2 = Na20.3.3SiOz I n some cases, as for the higher ratio silicates in Table 3 = Xaz0.2.9Si02 11 = NanCOa VI, the data for oleate and stearate had to be estimat,etf 4 = Naz0.2.4SiOz 12 = Sa3PO4 5 = NaaO.2.OSiOz 13 = NarPzO? from Bolton’s paper (2). The stearate factor was ab6 = Na~0.1.6SiOn 14 = NasPaOls sumed identical and the oleate consumption was assumed 15 = (NaPOd6 7 = Naz0.1.OSiOz t o increase 0.02 gram. For 2.0- and 2.4-ratio silicate, tht. laurate soap value had to be assumed. Ruff’s equation given below gives values calculated on the basis that the amount of hardness softened by a gram of mixed soap will be the reciprocal of the demand which is to be calculated and will equal Lr. c~~~~~~~~~~~ OF R~~~~~~os sOIL R~~~~~~~ (3)WITH the sum of the reciprocals of each individual soa demand, as deter3lrlv1xunr SOAP REQTJIRED TO FORM PERAXANENT SUDS mined experimenttilly, multiplied by their Kactional value in (At 0.1% anhydrous builder) the mixed soap. Kettle Soap Cobbs’ Soap Min. -
-
Soil
Naz0.3.3SiOz
anhyd. oonon. for suds 0.166
Naz0.2.OSiOz
0.150
10.6
Naz0.1.OSiOz
0.150
11.1’
NesPOi
0,140
10.9
NarPzO7
0.145
9.5
NazCOl
0.125
10.6
0.17 0.27
Na~B407
0.235
8.9
0.22
Anhydrous Builder, 0.1%
pH of soh.
10.0
Conon. anhyd.
0.17 0.27 0.17 0.27 0.17 0.27
0.17 0.27 0.17 0.27
0.27
pH of removal, soh 76 10.1 33 10.2 46
10.6
10.8 11.4 11.8
11.8 11.8 9.3
9.8 10.8 10.6 8.9 8.9
43 68 55
60 45 62 47 G5
40
61 26 38
Foam
Height,
In.
0.0 0.2
0.0
4.0 0.2 0.3 0.0 0.5 1.0 4.0 0 .o 0.5 Trace Trace
Sk = grams of kettle soap required t o soften 100 ml. of 300 p.p.m. water = grams of individual soaps 1,2,. . .n required t o 0 ml. of 300 p.p.m~water F1, . . = fractional value of the individual soaps in the ket,tle soap
Table V I compares calculated valum with experimental values for representative alkalies a t 0.05, 0.10, and 0.20% concentration shown in Figure 4. Several large extrapolations were required a t 0.20% concentration and several show differences of about 10%. Borax shows a consistently negative difference of
March 1949 TABLEVI. Anhydrous Builder Naa0.3.9SiOz Naz0.2.4SiOz Naz0.2.0SiOz NaeSiOa NaOH NazCOa NazBLh NaaPzO7(NaPOsh (adj.) None
INDUSTRIAL AND ENGINEERING CHEMISTRY CONPARISON OF KETTLESOAPCONTENT AT MINIMUM SUDSWITH THATCALCULATED FROM OTHERDATA 0.05 G./100 311. Found, Calod., Diff., g.
g.
8.
0.205 0.152 0.176 0.163 0.139 0.138 0.236 0.159 0.144 0.241
0.201 0.175 0.175 0.166 0.144
-0.004 10.023 -0,001 +0.003 10.005 +0.018 -0.020 +0.008 +0.004
0.166
0.216 0.167 0.148 0.166
-0.055
0.10 G./100 M1. Found, Calcd., Diff., g.
B.
0.166 0.176 0.144 0.149 0.151 0.148 0.153 0.171 0.138 0.130 0.126 0.122 0.235 0.214 0.148 0.151 0.109 0.115 ,
..
,,
.
0.20 G./100 MI. Found, Cttlcd., Diff.
g.
B.
g.
g.
fO.010
0.146 0.134 0.139 0.141 0.136 0.105 0.235 0.129 .0.064
0.160 0,134 0.126 0.147
f0.014
f0.005
-0.003 f0.018
-0.008 -0.004 -0.021 +0.003 f0.006
...
...
0.126
0,112 0.214 0.127 0.053
...
-0:Oi3 10.006 -0,010 +0.007 -0.022 -0.002 -0.011
...
581
Both silicates and phosphates may be employed t o prevent the formation of hard lime-soap curds. The adverse effect of caustic soda and soda ash was not as evident with soaps of lower molecular weight. The dispersion by 2.0and 2.4-silicon dioxide t o sodium oxide weight ratio silicates is notable. The results indicate t h a t a rigorous study of the additive effect of individual constituent soaps on minimum suds formation in hard water should be made. ACKNOWLEDGMENT
about 10% but is the only one showing such a n error in the same direction. The error of nearly 25% when no builder is present is probably caused by the lower fatty acids a t the p H of hydrolysis of the more alkaline soaps. Since the differences are generally less than 10% in spite of the numerous approximations and extrapolations required, there seems good reason to believe t h a t the effect of the individual soaps on the minimum required for formation of a permanent suds is additive under conditions of like pH. The problem deserves a more precise study. CONCLUSIONS
The following conclusions may be drawn from combining the prior work of Bolton (a) with the present work.
All the alkalies except borax decreased the amount of soaps re quired to form permanent suds in hard water when the carbon chain was greater than C = 14. Some silicate8 showed t o peculiar advantage with the high molecular weight soaps, while only the polyphosphates gave any reduction with low molecular weights. The silicates usually increased in value with decreasing silicon dioxide t o sodium oxide ratio. I n some cases the intermediate ratios 2.0 and 2.4 were more effective than 1.6.
Thanks are due to C. L. Baker who directed the project and other colleagues who have contributed from their experience. LITERATURE CITED
Am. Pub. Health Assoc., “Standard Methods of Water Analysis,” 8th ed., p. 61, 1936. Bolton, H. L., IND.ENO.CHEM.,34,737 (1942). Cobbs, W. H., Harris, J. C., and Eck, J. It., Oil & Soap, 17, 4 (1940).
Fuchs, J. N. von, Diliglers Polytech. J . , 17, 465 (1825); 142 305 (1850).
Gilmore, B. H., Oil & Soap, 12, 29-32 (1935). Kuent~el,L. E., Hensley, J. W., and Bacon, L. R., IN^. EKO. CHEM.,35, 1286 (1943). Miles, G. D., and Ross, J., J. Phys. Chem., 48, 280 (1944). Philadelphia Quartz Co., “Beginning Another Century,” 1931. Ruff, E. E.,Oil & Soap, 22, 125 (1945). Vail, J. G.,“Soluble Silicates in Industry,” A.C.S. Monograph 46,p. 12, New York, Reinhold Publishing Corp., 1928. Wegst, W. F., and Wills, J. H., U. 5. Patent 2,179,806(Nov. 14, 1939. RECEIVED April 16, 1946. Presented before the Division of Industrial and Engineering Chemistry a t the 109th Meeting of the AMERICAN CHEMICAL SOCIETY,Atlantic City, N. J.
Composition of Colorado
Shale-Oil Naphtha JOHN S. BALL, G. U. DINNEEN, J..R. SMITH, C. W. BAILEY, AND ROBIN VAN METER United States Bureau of Mines, Laramie, Wyo. Naphthas distilled from crude shale oils produced by several methods of retorting Colorado oil shale were analyzed and found to be remarkably similar. Consequently, only one was selected for a detailed composition study. The results indicate that the approximate composition of raw shale-oil naphtha is: paraffins and naphthenes 30%; olefins 40%; aromatics 20%0; sulfur, nitrogen, and oxygen compounds 10%. Paraffins and aliphatic olefins, which comprise about two thirds of their respective groups, are predominantly straight-chain compounds. The sulfur, nitrogen, and oxygen are present principally in the form of thiophenes, pyridines, and phenols, respectively.
I L shale, as it occurs in nature, consists of solid organic material interspersed in a shale formation. This organic matter can be converted by means of heat to lower molecular weight liquid products. Various retorting processes are used for this conversion of organic material to shale oil. The Bureau
of &fines, as,part of the Synthetic Liquid Fuels Program (6),has established a n Oil-Shale Research and Development Laboratory at Laramie, Wyo., to study retorting and refining processes. One phase of this study is a n investigation of the composition of ahale oil. The present paper reports results on material in the naphtha boiling range. A comparison was made of the composition of naphthas from different shale oils, and a n extensive investigation was made on one of them. This study involved separation of the raw naphtha into neutral naphtha, t a r acids, and t a r bases. A sample of the neutral naphtha was distilled in an efficient fractionating oolumn and a quantitative determination was made of the paraffins, naphthenes, aliphatic olefins, cyclic olefins, aromatics, sulfur compounds, and nitrogen compounds present in each fraction. A similar distillation was performed on a sample of neutral naphtha in which the olefins had been hydrogenated. A sample of the t a r acids was distilled under reduced pressure in a semimicro fractionating column and ultraviolet absorption spectrograms were obtained on the fractions. A sample of the tar bases was
