ANALYTICAL EDITION
276
TABLEI. DETERMINATION OF COBALT EXPERI-0.1N KgCraOi.USED MINT Analysis Blank cc. cc . 24.28 1 15.89 24.28 2 15.87 24.28 15.88 3 24.28 4 15.91 24.28 5 15.91 24.70 16.28 6a 24.70 16.32 7a 24.77 16.34 8 16.37 24.77 9 24.77 16.41 10 24>77 16.40 11 24.77 16.40 12 24.77 16.35 13 24.77 16.37 14 24.77 16 33 15 24.77 16.34 16 24.77 17 16.32 24.77 16.37 18 24.77 19 8.02 24.77 20 8.00 a Experiments 6 and 7 contained I
COBALT Present Found Gram
ERROR %
Gram
0,0495 0.0 0.0495 0.0496 0.2 0,0495 0.0 0.0495 0.0495 -0.3 0.04940.0495 -0.3 0.04940.0495 0.3 0.0496 0.0495 -0.2 0.0494 0.0495 0.4 0.0497 0.0495 0.0495 0.0 0.0495 -0.4 0.0493 0.0495 0.04946 -0.3 0.0495 -0.2 0.04940.0495 0.3 0.0496 0.0495 0,0495 0.0 0.0495 0.049740.5 0.0495 0.5 0.0497 0.0495 0.0498 0.6 0,0495 0.0 0.0495 0,0495 -0.2 0.0988 0.0990 -0.1 0.0989 0.0990 20 and 40 mg. of nickel, respectively.
+
+
ACCURACY.A few typical results are given in Table I Lo illustrhte the accuracy which is possible by this method.
Experiments 1 to 5 were performed in an apparatus con-
Vol. 5, No. 4
structed entirely of Pyrex, while 6 to 20 were carried out in an ordinary apparatus with a paraffined rubber stopper.
SUMMARY The method described above has been developed for the use of sodium perborate, ferrous sulfate, and potassium dichromate in the volumetric determination of cobalt, and is believed to be the most rapid, convenient, and accurate so far proposed. Diphenylamine sulfonic acid is recommended as indicator. LITERATURE CITED (1) Classen. A.. and Cloeren. H.. tr. bx Hall., “Quantitative Analysis by Electrolysis,” p. 192, Wiley; 1919. (2) Engle, W. D., and Gustavson, R. G., J. IND.ENG.CHEM.,8, 901 (1916). (3) Gillis, J., and Cuvelier, V., Natuumu. Tijdschr., 1 1 , 2 0 , 1 2 3 (1929). (4) Sarver, L. A., and Kolthoff, I. M., J. Am. Chem. Soc., 53, 2902 (1931). ( 5 ) Willard, H. H., and
Hall, D., Ibid., 44,
2219, 2237 (1922).
RECBIVBD April 26, 1933.
Nomograph for Rapid Calculation of Sulfate-Carbonate Ratios ROBERTT. SHEEN,W. H. & L. D. Betz, Philadelphia, Pa. LARGE number of plants and laboratories calculate ratios of sodium sulfate to total alkalinity when exPressed 8s sodium carbonate, to ascertain whether Or not the result is within the limits as prescribed by the American Society of Mechanical Engineers for the inhibition of caustic metal embrittlement. Most laboratories report sulfates in terms of the radical SO4 and alkalinities in terms of c a l c i u m c a r b o n a t e . To convert ‘sulfates to sodium sulfate, it is necessary to multiply by 1.479-that is, SO4 x 1.479 = Na2S04. To calculate total a l k a l i n i t y as calcium carbonate in terms of sodium carbonate, it is necessary to multiply by the factor 1.06-that is, CaC03 X 1.06 = Na2C03. To calculate the sulfate-carbonate ratio, the first result is divided by the $ second. The accompanying nomograph accomplishes the same result in one operation. Given sulfates in terms of SO1 and total alkalinity in terms of CaC03, the ratio
A
For Pressures over 250 pounds, 3 parts sodium sulfate to 1 part The following examples illustrate the use of the chart: EXAMPLE 1. Given an analysis in parts per million, part of which reads as follows: Sulfates @or) Alkalinity as CaCOa: Bicarbonates Carbonates Hydroxides
s
2
NazCOa straight line from the total alkalinity axis at the given figure t h r o u g h the given figure on the sulfate axis and reading the result directly on the ratio axis. A. S. M. E. REQUIREMENTS. The ratio in each case is the minimum ratio required. For pressures up to 150 pounds, 1 part sodium sulfate t o 1 part total alkalinity. For pressures from 150 to 250 pounds, 2 parts sodium sulfate t o 1 part total
alkalinity.
A
0 154 196
The total alkalinity, the sum of carbonates and hydroxides as given in this anal sis, is 350 parts per million. Start a straigzi line from this point on the total alkalinity axis intersecting the sulfate axis at 300 parts per million and the corres onding ratio will be found to be 1.19 on tKe ratio axis. This ratio is satisfactory for boilers operating below 150 pounds pressure but is unsatisfactory for boilers over 150 pounds. Mathematically, the following calculations would have been required: S 0 r X 1.479 CaCOa X 1.06
Na2S04 may be read b y e x t e n d i n g a
300
300 X 1.479 360 X 1.08
1.19
EXAMPLE 2. Given an analysis in parts per million, part of which reads as follows: Sulfates (804) Alktlinity a0 CaCOa: Bicarbonates Carbon[ttes Hydroxides
300 0 188 312
The total alkalinity, the sum of carbonates and hydroxides as given in this FIGURE 1. NOMOGRAPH FOR CALanalysis, is 500 parts per million. Start a CULATING SULFATE-CARBONATEline from 500 parts per million on the total RATIOS FOR INHIBITION OF CAUSTIC alkalinity axis, intersecting the sulfate axis METALEMBRITTLEMENT at 300 parts per million, and it will strike .I
July 15, 1933
INDUSTRIAL AND ENGINEERING
the ratio axis at 0.84. This ratio is unsatisfactory for boilers operating at any pressure. The chart may also be used by those working with results in terms of grains per U. S. gallon without converting to parts per million, because the conversion factor from parts per million to grains per gallon is cancelled in the ratio. To aid in reading, however, the figures on both the total alkalinity and the sulfate scales should be divided by 10. For example, if sulfates were given as 30 grains per gallon (Example 2), and
CHEMISTRY
271
total alkalinity as 50 grains, the resulting ratio would be 0.84. ACKNOWLEDGMENT The author wishes to acknowledge the kind assistance of E. M. Ross for his help in certain calculations and preparations of the nomograph. RECEIVEDApril 6, 1933. Presented before the Division of Water, Sewage. and Sanitation Chemistry at the 85th Meeting of the American Chemical Society, Washington, D. C., March 26 to 31, 1933.
Identification of Amines as 3,5-Dinitrobenzoates C. A. BUEHLER,E. JANECURRIER,AND RAYLAWRENCE Department of Chemistry, University of Tennessee, Knoxville, Tenn.
T
HE amine salts of various sulfonic acids (8, 6) have
been recommended as derivatives for the identification of amines. This investigation concerns itself with the carboxylic acid-3,5-dinitrobenzoic acid-which appears to offer some advantages over the sulfonic acids as a reagent to be used in amine identification. I n brief, it may be stated that the 3,5-dinitrobenzoic acid is more readily available or more easily prepared; it combines with a great variety of aliphatic and aromatic amines to form salts which usually have low, sharp melting points; and the salts, as a rule, are easily prepared and purified. Although the amine salts of 3,5-dinitrobenzoic acid are not as stable as the acetyl or benzoyl derivatives of the amines, TABLE I.
their stability is such that recrystallization commonly leads to compounds having melting points sufficiently definite for identification purposes. Frequently the former are more easily prepared in a pure state than the latter. I n addition, while the acyl derivatives may be formed with primary and secondary amines, the 3,5-dinitrobenzoates are capable of being produced for all types of amines. Failures in the latter case appear to be due to the insufficient basicity of the amine. The results are summarized in Table I, which also contains for comparison the melting points of the corresponding ptoluene sulfonates. None of these compounds, with the exception of those of ammonia (3) and pyridine (7), appear to have been described.
3,5-DINITROBENZOATES O F
AMINES MBLTINQ
RE-
AMINE
CRYSTALLIZATIONB
MELTINQPOINT
Obs.
c.
Corr. O
c.
COLOR
MOLARNEUTRAL EQUIVALENTNITROQEN RATIO Calcd. Found Calcd. Found
OF
P O I N T (6)
TOLUENE.
SULFONATE
Aniline 1 Light yellow 1:l 305.1 302.7 i3.77 13.65 238.4 1 o-Toluidine White 319.1 1:l 313.8 13.17 13.13 189.7-190.5 0a m-Toluidine Light yellow 1:l 319.1 317.5 13.17 13.20 174.6-176.1 1 p-Toluidine Orange l!l 319.1 316.3 13.17 13.14 197.7-199.2 4-Amino-1 3-dimethylk)enzene 2 Light tan 1:l 333.1 12.52 339.0 12.61 180.4-181.3 1 o-Chloroadiline Bright yellow 1:l 339.6 341.9 12.28 12.38 192.9-193.6 1 m-Chloroaniline Yellow 1:l 339.6 339.1 12.37 12.38 209.8-210.3 1 p-Chloroaniline Yellow 1:l 339.6 333.4 12.38 12.57 213-231 1 p-Bromoaniline Yellow 1:l 384.0 381.2 10.94 10.94 214.2-234.2 +Nitroaniline Oil 21, m-Nitroaniline Orange 1:l 350.1 341.9 16.00 16.12 213.5-215.0 l b p-Nitroaniline Yellow 1: 1 350.1 34!. 6 16.00 16.09 232.2-234.7 2 p-Amjno henol Yellow 1:l 13.09 12.88 252.1-253.6 1 o-Aminogenzoic acid 1:l 174.6 Bright yellow 169.5 12.04 11.87 224.1-224.6 1 m-Aminobenzoic acid Orange 1:l 174.6 176.9 12.04 12.01 255.9-256.5 2 p-Aminobenzoic acid Orange 1:l 176.1 174.6 12.04 11.97 238.6-241.6 05 Methylaniline Li$;eyellow 1:l 319.1 315.0 13.17 13.12 Oil 1 Dimethylaniline 2:l 272.6 272.1 12.85 12.66 Oil 2e Benzylaniiine Faint yellow 1:l 395.2 389.9 10.63 10.71 148.3-148.8 Dibenzy!aniline Oil 1 Acetanilide Yellow 1:l 347.1 339.9 12.11 12.00 Diphenylamine Tri henylamine 1 6 o-Pien ylenediamine Yellow 320.1 1:l 17.70 17.50 267.3-268.8 0 m-Phenylenediamine Yellow 320.1 1:l 17.35 17.50 296.8-297.8 2" p-Phenylenediamine Yellow 320.1 1:l 17.65 >340 17.50 2 a-Naphthylamine Red 355.1 1:l 11.83 11.82 248.4-249.91 1 @-Naphthylamine Y$llOW 355.1 1:l 217.3-219.1 11.83 11.74 1 Benzidine Light yellow 304.1 2:l 13.82 13.65 1 Pyridine L&teyellow 2:l 251.6 f lo Quinoline 1:1 341.1 f Ammonia 0 Yellow 229.1 1:l 18.34 18.40 ......... Benzylamine 1 Yellow 319.1 1:l 13.17 13.12 184.5-185.6 2 Diethylamine Light yellow 1:l 285.1 14.60 ......... 14.74 Oa Triethylamine Light yellow 1:l 313.2 13.42 13.30 ......... 26 Urea 272.2 Light yellow 1:l 20.59 ......... 20.68 05 Acetamide 241.6 Light yellow 2:l 14.49 14.50 ......... Benzamide 2 White 333.1 1:l 12.62 12.73 .......... Decomposition occurred on redissohing compound. a Recrystallized from mixture of alcohol and benzene b Recrystallized from cold benzene. f Nitrogen could not be determined by Kjeldahl method. 0 Determination was not possible because of intense color produced in solution. I Recryetallized from hot benzene. d Compound turned dark below melting point.
......... ......... .........
