V O L U M E 2 1 , NO. 7, J U L Y 1 9 4 9 Ibid., 60, 228 (1946). I b i d . , 61, 63 (1947). Ihid., 61, 79 (1947). I b i d . , 61, 148 (1947).
Lecat, “Azeotropisme,” Brussels, Henri Lalilertin. 1918. Lecat, Compt. rend., 217, 242 (1943). Ibid., 222, 733, 882, 1485 (1946). Ibid., 223, 286 (1946). Lecat, Z . anorg. allgem. Chem., 186, 119 (1929). Lepingle, Bull. SOC. chim.. 39, 864 (1926). Lidstone, J. Chem. SOC.,1940, 241. Litkenhous, Van Arsdale, and Hutrhison, J . Ph!/s. C’hpm.,44, 377 (1940). McDermott, I;. A , , private cotntnunication. Marshall, J . Chem. SOC.,89, 1351 (1906). Matuszak and Frey, IND. Esc. CHEM.,.\s.AI.. KD.,9, 111 (1937). Nadeau and Fisher, U.S. Patent 2,105.298 (1939). Natta, I b i d . , 2,308,229 (1943). Naumann, Ber., 10, 1421, 1819, 2099 (1877). Oddo, Gam, chim. ital., 41, 11, 232 (1911). Othmer, Ind. Eng. Chem., 35, 614 (1943). Othmer, U. S. Patent 2,050,234 (1936). Ibid., 2,170,831 (1939). Ibid.,2,395,010 (1946). Othmer, Schlerhter, and Kosyalka, I n d . E/tn. C ‘ h e m . , 37, 895 (1945). Patterson, U. S. Patent 2,407,997 (1946,. Petry, Ihid., 2,411,106 (1946). Pierre, Compt. rend., 74, 224 (1872). Piret and Hall, I n d . Eng. Chem., 40, 661 (1948). Popelier, B d I . S O C . sci. Relg., 32, 179 (1923). U) Pratt, Preprint, Trans. Inst. C‘hem. E ~ L ~( LSO. I L ~ O(Marcll 1947). Pryanishnikov and Genin, J . Applied Chem. ( L ’ 140 (1940). Quiggle and E‘enske, J . Am. Chem. Soc., 59, 1829 (1937). Reinders and Min.ier, Rec. trau. chim., 66, 552, 564. 573 (1947). Richards and Guinot, U. S. Patent 1,915,003 (1933). liiethof, I b i d . , 2,413,649-51 (1946). Robinson, “Elements of Fractional Distillation,” 1,. 280, New York, McGraw-Hill Book Co., 1930.
873 Sandberg and Patterson, U. S. Patent 2,428,815 (1947). Sauer and Hadsell, J . Am. Chem. SOC..70, 4258 (1948). Sauer, Schreiber, and Hadsell, Ibid., 70, 4254 (1948). Schelling and Anderson, U. S. Patent 2,422,802 (1947). Schopmeyer and Arnold, Ibid., 2,350,370 (1944). Schreinmakers, 2. physik. Chem., 39, 485: 40, 440 (1902), Senkus, U. S. Patent 2,406,713 (1946). Shawinigan Chemicals, Ltd., Dept. Chetn. Divd., “Report on Vinyl Crotonate,” (1948). Shell Chemical Gorp., “Organic Chemicals Manufactured h>Shell,” 1939. Shell Development Co., Data Sheet, 1946. ShostakovskiK and Prileshaera, J. Gen. Chem. (C..S.S.R.), 17, 1129 (1947). Simonetta and Barakan, Gazz. chim. ital., 77, 105 (t947). Smith, U. S. Patent 2,3385,546 (1945). Smvth and Eneel. J . Am. Chem. Soc.. 51. 2646 (1929). Soci6t6 des usines chiniiques IihBne-Ponlenc, BI it. Patent 595,738 (1947). Speck, U. S. Patent 2,449,152 (1948). Speier, J . Am. Chem. Sot.. 70, 4142 (1948). Stasse, U. S. Patent 2,363,158 (1944). Steel and Bagstor, J . Chem. Soc., 97, 2607 (1910). Stengel and O’Loughton, U.S. Patent 2,315,139 (1943). Sullivan, Ibid., 2,265,220 (1941). Sutherland, Ibid.,2,290,654 (1942). Timmermans. J . chim. p h y s . , 31, 98 (1934). Tomkins, Wheat, and Stranks, Can. J . Research, 26F, 168 (1948). Trillat and Cambies, Compt. rend., 118, 1277 (1894). Tyerman, Brit. Patent 590,713 (1947). Walker and Carliale, Chem. Eng. ‘Vews, 21, 1250 (1943). Welling, C. 8. Patent 2,386,375 (1945). Willert, I b i d . , 2,445,738 (1948). Williams, Trans. Am. Inut. Chem. Engrs., 37, 157 (1941). . 20, 733 (1948). Williams and Meeker, . ~ N . A L CHEM., Woods, J . SOC.Chem. Ind., 66, 26 (1947). Wuyts, Bull. SOC. chim. Belg., 33, 178 (1924). Wuyts and Docquier, Ibid., 44, 297 (1935). Young and Fortey, J . Chem. Soc., 81, 739 (1942). I
High Temperature Bath Made from Aluminum Shavings STEPHEN DJANG Michigari S t a t e College, East Lansing, .Mich. l H E : need for a high temperature bath for refluxing aqueous solutions led to the work presented in this paper. Because of their high conductivity of heat, aluminum shavings were used in construction of the bath. A copper box r h i c h contains aluminum turnings about the size of rice granules is placed on top of a copper plate 0.6 cm. (0.25 inch) thick and fastened by screws. T h e copper plate is heated 1)y three electric elements and the heat is regulated and controlled bv a thermoregulator, which is located in the center of thc 1)ath (Figure 1). Because of the high conductivity of copper, a uniform temperature bath can be constructed. The copper plate must be thick enoueh to diffuse sufficient heat to the entire unit. The entire bath-is enclosed in a box of Transitc, so that the uniform temperature of the hath can be preserved. T h e space bet’ween the copper hox and the Transitc wall measures 2.5 cm. (1 inch) and is filled with rock wool as insulator. The bath is covered Ivith individual Transitc covers with notches to accommodate the necks of the flasks. T h e inside of the bath is 40 inches in length, 6 inches in width, and 4.5 inches in depth. Eight 300-ml. round-bottomed flasks (’an be set, in a row. T h e flasks are placed in metal cups, which are 236-m1. (&ounce) aluminum measuring cups with handles i ~ m o v e d . If flasks break, the solution is trapped in the cups (Figure 1). T h e flasks are cushioned in the cups with Chore-
girl copper ribbon material which retains its form. Aluniiiium shavings were not satisfactory because they did not retain a definite form to accommodate t,he shape of the flasks. Hoivcver, the bath can he operated without, the use of metal cups. I n packing the bath the eight metal cups with their contents are placed on the bottom of the box (Figures 1 and 2 ) . Then the aluminum shavings are poured in to a depth of 0.75 inch, evenly distributed hut not pressed or tamped. Two aluminum bars, 39 inches long and 0.5 inch in diameter, are laid on top of the aluminum shavings in front and in back of the metal cups but not touching the cups or the side walls of the bath. After all are in position, thc bath is filled with aluminum shavings up to 1 inch from the top. T h e aluminum bars are used as heat conductors (Figures 2 and 3). The bath was tested for 50 hours of continuous operation at 200” C. Recordings at five different positions in the bath showed that the fluctuation of temperature at all positions was the same, =+=l.j0 C. (Table I). It was demonstrated that the temperature of the bath was even and constant at various positions in thc bath when the thermoregulator was set a t 200” C. When the thermoregulator was set a t temperatures ranging from 30” to 250” C. for 12-hour periods, the bath held t.he given temperature throughout the period tested. The author \vas in-
ANALYTICAL CHEMISTRY
874
Table I. Temperature Variations a t Five Positions i n t h e Bath ThermoTime, regulator Min. Pilot Light Off 0 2 Off 4
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
40
42 44 46
?
00
Off
On On On On On On On Off Off Off Off
Off
Off Off On On On On On
Off
Off Off
Off
;12 .i4
Off
.i8 60
On On
;. R
Off Off
Highest reading Lowest reading Range or variation Fluctuation
1
2
3
4
5
201 201 201 201 200 199 198 199 199.5 200 200 200 200.5 200.5 200.5 200 200 200 199 198.5 198.5 198.5 199 199 200 200 200 200 199.5 198,5 198
203 203 203 202 201 200 200 200.5 201 201 201 202 203 203 202 202 202 201 200 200 200 200 201 201 202 202 202 201.5 201 200 200
201 201 20 1 200 199 198 198 198 198 199 200 200 200.5 201 200.5 200.5 200 199.5 198.5 198.5 198 198 199 199.5 200 200 200 200 199.5 199 199,5
202 202,5 203 202 200 200 200 200 200 200,5 201 201.5 202 202 202 201 200.5 200 200 200 200 200 200 200 201 201 201 200 5 200 200 199.J
201 201 201 200 200 199 199 199.5 200 200.5 201 201 201.5 200 200 199 199 199 199.5 199 199 199 200 200 200.5 201 200.5 200.5 200 199.5 199
201 198 3 *1,5
203 200 3 tl.5
201 198 3 *1,5
203 200 3 tl.5
201 199 2 *l
c.
c.
c.
c.
c.
terebted in securing a bath which was constant a t temperatures between 150" and 250" C. and compiled detailed data only a t 200" C. Temperatures higher than 250" C. could be secured by adding more heating elements. The bath so constructed is especially useful a t or above 100" C. for refluxing samples for long periods. Aluminum shavings are noncorrosive and always appear clean. Below 100" C.
Figure 1. Front section \ w w
::: p,,
Rock wool insulation
1 Copper
plate
Heating element
'???y
320-ml. flask placed in
Aluminum shavings
0
vhh
Position of thermoregulator
Figure 2 , Top section view Flask Aluminum shavinxs
:a'6'
1
metal cup, cushioned with chore-girl copper ribbon
Aluminum bar Rock wool insulation
Figure 3. End section view Aluminum bars
,,
Heating elements
= Copper plate the shaving bath has one advantage over a water bath: no liquid escapes by evaporation. There is no danger from fumes as with acids or organic liquids; hence this bath is safer for the operator and avoids contamination of samples. The cost of the material, except the thermoregulator, for building the bath is between $12 and $15. The thermoregulator is manufactured by Fenwal, Inc., Ashland, Mass. An aluminum plate 0.375 inch thick, 40 inches by 6 inches, weighing 10 pounds may be used instead of copper (cost $3). Aluminum shavings are obtainable a t machine shops at 10 cents per pound. RECEIVEDApril 28, 1948.
Detection of Persulfate in Acid 'Solution GEORGE L. CLARK AND TSONG-CHI TSO University of Illinois, Urbana, Ill.
HE common reagents that are relatively sensitive and simple? sulfuric acid, no crystals are formed in high concentration of Tin use for persulfate (szos--)detection are aniline, benzi- ,flJpersulfate. I n 5 N or lower acid solutions, crystals of exactly the same form as in neutral solutions are obtained, the limit of dilu-
dine, 2,7-diaminofluorene, and Zwikker reagent. The first three reagents show color changes due to oxidation of the reagent by persulfate ion, while the last one gives definite and highly typical crystals after reaction with persulfate. All four reagents are very sensitive in neutral solution when used according to the directions in analytical books. For detection of persulfate in strong acid solutions, the situation is different, The authors have studied the behavior of these four reagents in both neutral and acid solutions of various strengths. Some modifications of the method using two of the reagents have been developed for detection of persulfate in acid solutions. This is of particular importance in the case of persulfuric acid formation a t the anode during charging of storage batteries a t temperatures as low as -65" F., a t which the acid is far more stable than a t room temperatures, with resulting solution of lead dioxide and gradual disintegration of the positive plates.
Zwikker Reagent (4 ml. of 10% copper sulfate, 1 ml. of pyridine, and 5 ml. of water) forms specific prismatic crystals with persulfate in neutral solution. The limit of dilution is found in this work to be 1 to 5000 (1 part of persulfate in 5000 parts of neutral solution), but that found by Berisso ( 1 ) was 1 to 10,000 and that by Wagenaar ( 4 ) was 1 to 1000. In a 10-\I solution of
tion varying with the strength of acid (Table I). Therefore. to test for Dersulfate ion in acid solution with Zwikker reagent, the sampie solution must be diluted before the reagent is added. To prevent the decomposition of persulfate by heat of dilution, the solution should be kept cold during dilution. 2,7-Diaminofluorene (3, 7 ) is synthesized by nitration of fluorene, followed by reduction of the nitration product with tin and hydrochloric acid. Crystals of 2, 7-diaminofluorene hydrochloride are obtained on precipitating the tin with hydrogen sulfide and evaporating the solution. Usually, an aqueous solution of 2,7-diaminofluorene or its hydrochloride is used for the detection of persulfate. In neutral solution, potassium persulfate gives a distinct blue coloration a t a dilution of 1 to 200,000 with a 1 % solution of the reagent.
Table I.
Limit of Dilution with Zwikker Reagent
Acid Normality i n Persulfate Solution 10 5 2 1
0.5 0.0
Sensitivity &Os-- not detectable in all concentrations 1 p a r t Stoa-- detectable i n 500 parts solution 1 part SzOs-- detectable i n 1000 parts solution 1 p a r t SaOa-- detectable in 2000 parts solution 1 part S,O8-- detectablcin 2000 parts solution 1 part SzOs-- detectable in 5000 parts solution
