256
J. A, ADDLESTONE, L. R . MARSH, AND G . C. HALL
THE SYSTEM SILVER SULFATE-ALUMINUM SULFATE-WATER' J. A. ADDLESTONE, L. R. MARSH,
AND
G . C. HALL
Department of Chemistry, Virginia Polytechnic Institute, Blacksburg, Virginia Received May 66, 1959
There are conflicting reports in the literature concerning the existence of silver alum. Kern (3) reported having made typical crystals of silver alum by evaporation of a mixed solution of silver sulfate and aluminum sulfate. Church and Korthcote (2) described the preparation of this alum by heating a mixture of silver sulfate, aluminum sulfate, and water in a sealed tube until all the silver salt had dissolved. Both of these methods have been employed by other investigators (1) without being able to produce silver alum. Caven and Mitchell (1) investigated the system silver sulfate-aluminum sulfate-water and concluded that a crystalline silver alum does not form a t 30°C. The present study was undertaken with the purpose of obtaining isotherms for this system at OOC., 25"C., and 45OC. EXPERIMENTAL PROCEDURE
Solutions were made, using C.P. silver sulfate and aluminum sulfate. For each isotherm a series of solutions was prepared containing varying concentrations of aluminum sulfate in contact with solid silver sulfate, and other solutions containing silver sulfate solutions in contact with solid aluminum sulfate. The solutions were placed in a constant-temperature water bath for the 25°C. and 45°C. isotherms, and in a water-ice mixture for the 0°C. isotherm. The solutions were shaken several times daily for a week and then allowed to settle completely so that the supernatant liquid was clear. It was shown by duplicate analyses that this allowed sufficient time for equilibrium to be reached. Samples of the clear liquid were taken for analysis through pipets with cotton filters. The solid phase was sampled with a glass spoon and as much of the liquid as possible was allowed to drain off. Silver was determined volumetrically by the thiocyanate inet hod, and aluminum was determined by precipitation and ignition to the oxide. The silver was calculated to silver sulfate and the aluminum to aluminum sulfate; water was determined by difference. The composition of the solid phase in equilibrium with the various solutions was determined 1 This paper is an abstract of theses submitted by L. R. Marsh and G . C. Hall in partial fulfillment of the requirements for the B.8. degree in chemistry. FIQ. 1. Solubility isotherms for the system silver sulfate-aluminum sulfatewater
THE SYBTEM SILVER SULFATE-ALUMINUM
SULFATE-WATER
257
graphically by means of intersecting tie-lines on a large-scale triangular diagram. TABLE 1 0 ° C . isotherm L I g U I D PHASE
WET RESIDUE SOLID PHASE
mded
0.0177 0.0179 0.0185 0.0205 0.0211 0.0211 0.0213 0.0218 0
mola
AgzSOr
Alr(SO4r
per c a t
per cent
p a cent
54.74
2.17
43.09
62.36
3.92
33.72
47.26 27.45
8.10 30.35
44.64 43.20
0
0.0828 0.1674 0.2506 0.3294 0.5245 0.5956 0.8488
0.8938 TABLE 2 %6"C.isotherm
LIQUID PHASE
WET REllIDUE SOLID PHASE
AgrSOi molu
0.0272 0.0277 0.0289 0.0290
0.0304 0.0307 0.0309 0.0310
mole8
p47 C e n t
0
0.1085 0.2946 0.3856 0.5141 0.6068 0.8564 1.047
71.42
3.27
25.31
61.66
6.26
32.08
59.10 8.23 0.19
10.32 40.18 40.00
30.58 51.59 59.81
DATA AND CONCLUSIONS
The data for the three isotherms are given in tables 1 to 3 and shown graphically in figure 1. An inspection of these curves indicates that each isotherm consists of two solubility curves with no evidence of compound formation.
258
J. A. ADDLESTONE, L. R. MARSH, AND G . C. HALL
TABLE 3 46°C. isotherm LIQmDPHASE
Moles
h s o 4
Moles AL(BO4)I
I
WET BYUDUI
w 1oM) g.
A#tso4
Ah(804)l
mdss
mdcs
par cent
p s cant
pa cent
0.0333 0.0351 0.0376 0.0386 0.0397 0.0399 0.0402 0
0 0.0961 0.1911 0.3587 0.5568 0.7384 1.284 1.366
52.87
2.25
44.88
41.83
7.04
51.13
42.89 40.56
12.14 18.07
44.97 41.37
par 1000 8. H a
Ha0
FIQ. 1
HYDROUS LANTHANUM HYDROXIDE AS EMULSIFYING AGENT
259
SUMMARY
The O"C., 25"C., and 45°C. isotherms for the system silver sulfatealuminum sulfate-water have been determined. The stable solid phases at these temperatures are AgZSOd and Alz(SO&.18H20. There is no evidence of the formation of silver alum as a solid phase at the temperatures used in this study. REFERENCES (1) CAVEN AND MITCHELL: 3. Chem. Soo. l!Z7,2550 (1925). (2) CHUECEAND NORTHCOTE: Chem. News 9, 155 (1864). (3) KEEN: Chem. News S1,209 (1875).
HYDROUS LANTHANUM HYDROXIDE AS AN EMULSIFYING AGENT THERALD MOELLER' Laboratory of General Chemistry, University of Wisconsin, Madison, Wisconsin Received July 84, 1958 INTRODUCTION
Very little information exists relative to agitating hydrous oxide and hydroxide sols with immiscible liquids, although it has been recognized that certain oxides and hydroxides can stabilize emulsions. Reinders (6) shook several sols, among them ferric oxide, with a number of organic liquids and found the suspended matter to concentrate a t the interface in nearly all cases. Briggs (1) found that a hydrous ferric oxide sol when shaken with either benzene or kerosene gave rise to oil-in-water emulsions providing a small amount of a weakly flocculating electrolyte were present. Klein (2) was unable to precipitate such sols as ferric and aluminum oxides with various organic compounds. In a preliminary experiment in which portions of a hydrous lanthanum hydroxide sol were shaken with equal volumes of different immiacible organic liquids, it was found that white foam-like emulsions floated to the top with benzene, toluene, and xylene. With ether, isoamyl alcohol, carbon tetrachloride, and chloroform, however, emulsions were not produced. 1 Present address: Noyes Chemical Laboratory, University of Illinois, Urbana, Illinois.
