INDUSTRIAL AND ENGINEERING
100
solved oxygen is much less important than at lower temperatures, and the corrosion rate under these conditions is probably controlled principally by the concentration of peroxides in the oil as Denison suggested. ACKNOWLEDGMENT
The authors extend their appreciation to the Lubri-Zol Corporation which sponsored this work.
CHEMISTRY
Vol. 37, No. 1
LITERATURE CITED
i;;
:r~~~~e~”~~:,3~~,42783((1~~~
(3) Fox, Analyst, 8, 116 (1883).
(4) Glasstone, Laidler, and Eyring, “Theory of Rate Processes”, p. 401, New York, MoGraw-Hill Pub. Co., 1941. (5) Kokatnur and Jelling, J . Am. Chem. SOC.,63, 1432 (1941). (6) Smith, B ~ and Mitchell, ~ ~ bid.,~61, 2407 ~ (1939). , (7) Staeger, Petroleum, 33, No. 7 , 1 (1937).
Useful Life of a Molecularly Dehydrated Phosphate in Sulfuric Acid ROBERT W. ATTEBERRY AND DONALD S. HERR The Resinous Products & Chemical Company, Philadelphia, Pa.
M
ORGEN and Swoope (2) measured the useful life of various molecularly dehydrated phosphates under varying conditions. The useful life of Calgon in 1 N sulfuric acid was not included among these studies, and so was investigated. It was 6rst necessary to set up an analytical method. The five following solutions were made up: SOLUTION I. 270 grams of 95.5% sulfuric acid were poured into 840 ml. of distilled water. After cooling, the volume was adjusted to 1 liter with distilled water. SOLUTION 11. 20 grams of C.P. ammonium molybdate were dissolved in distilled water and diluted to 1 liter with distilled water. SOLUTION 111. 0.5 ml. of concentrated stannous chloride solution (Betz and Betz Code No. 239) was added t o 20.0 ml. of distilled water, made up fresh daily. SOLUTION IV. 1.5073 grams of disodium orthophosphate (IYa2HP04)were dissolved in 1 liter of 1.0265 N sulfuric acid. This solution was found to be 0.0106 3f by the gravimetric method. SOLUTION V. Solution I V was diluted tenfold with 1.0265 N sulfuric acid. To 5.0 ml. of solution V were added 10.0 ml. each of solutions I and 11. Then 2.5 ml. of solution I11 was added, and after standing 30 minutes, n spectral transmission curve was run on the Coleman Universal spectrophotometer model 11. This curve showed a transmission maximum in the range 520-540 mw. [The general analytical method was described by Dunajew ( I ) . The point of maximum transmission was chosen since the spectral absorption TABLE I. TRANSMISSION DENSITIESOF ORTHOPHOSPHATE STANDARDS 1.0265
NO.
N
H*SO,,
M1.
Soh. Type
1.0 n n
v V
Ortho-
phosphate
Volume, 311.
Standard PO4---,
P.P.M.
Trans-
mission Density
4.0
TABLE 11. RATEOF CALGON HYDRATION ~ No.
i Hr.
~ ~ , Density Transmission Standard Calgon
P.P.M. PO* --in Cslgon
Hydration, yo
properties of reduced phosphomolybdic acid are more dependent upon p H than upon orthophosphate ion concentration. A low p H was used to recjxce the color intensity and wave length of maximum transmission was employed to obtain the greatest sensitivity of orthophosphate ion concentration.] The KlettSummerson photoelectric photometer, model 2071, which has a long logarithmic scale calibrated to read in relative terms of transmission density, was therefore abridged with the green No. 54 filter for use in this work. Standards of orthophosphate ion were set up as described in Table I , to which 10.0 ml. each of solutions I and I1 were added, and then 2.5 ml. of solution 111 were added. The transmission density vas measured in exactly 30 minutes after solution I11 was added in the tube model cuvette. Since the transmission density is a linear function of the concentration of orthophosphate ion, this method can be used to check the rate of hydration of Calgon. A 300-mg. portion of Calgon was dissolved in 1 liter of 1.0265 N sulfuric acid, and this solution was placed in a water bath maintained a t 25” * 2’ C. After measured intervals of time, 5.0 ml. of the solution were pipetted into a flask to which 10.0 ml. each of solutions I and I1 were added. Then 2.5 ml. of solution I11 were added, and the transmission density was measured in exactly 30 minutes in the tube model cuvette. Each time such an analysis for orthophosphate was made, a standard similar to No. 8 of Table I was analyzed, and the result served as a reference point for the linear relation between transmission density and the concentration of orthophosphate ion. Table I1 shows the results of the rate of the hydration. The per cent hydration is calculated by multiplying the ratio of orthophosphate ion concentration at the specified time to the final constant concentration of orthophosphate ion by 100. Thus, when per cent hydration is plotted against time, it is found that 50% ‘hydration occurred in 28 hours. Hence, the half life, or useful life in this case, of Calgon in normal sulfuric acid a t 25” C. is 28 hours. The use of sulfuric acid containing relatively small amounts of Calgon has been found more beneficial for the regeneratim of a cation exchange material than sulfuric acid alone. The effect of the metaphosphate even in the presence of acid prevents the deposition of calcium sulfate, etc., upon the exchanger bed, directly improves theefficiency of such a regeneration, and decreases the subsequent rinse water requirements. LITERATURE CITED
(1) Dunajew, A,, 2. anal. Chem., 80,252 (1930). (2) Morgen and Swoope, IND.ENO.CHEM.,35,821 (1943).
