STABILITY OF COPPERAND NICKELCHELATES OF PHTHALIC ACIDDERIVATIVES 1649
Dec., 1956
thermal decomposition of acetylene. The estimated precision of the analytical results is indicated INTENMTY OF THE (10)LINE AS A FUNCfor most of the parameters in the form of probable TION OF La deviations. It may be noted that Acetylene black I-. La (AJ I, shows the greatest growth in both the L a and ,Lcdi19 1.33 0.94 mensions, whereas Micronex shows the least. Con1.04 20 1.37 versely, Acetylene contains the least disorganized 21 1.41 1.08 carbon and Micronex the most. 22 1.45 1.13 1.17 24 1.52 TABLE I11 TABLE I1
COMPUTED PEAK Ln
(A., 10 12 13 14 15 16 17 18
1.21 1.25 1.29
26 28 30
1.58 1.65 1.70
to the (001) sequence, which is given by expression 1. The (001) computation must also take into account the arbitrary normalizing factor (0.86) required to put the calculated and observed intensities on a common basis, and both the (00)and (001)profiles are weakened by the disorganized fraction , 0.205. Subtracting the total intensity, 0.275, due to D, (OO), and (OOZ), from 1.10, we find 0.825 as the observed intensity due to (10) alone. However, this quantity, as measured, is also weakened by the disorganized fraction, so that we find for the equivalent theoretical (10) intensity of Micronex in the absence of disorganized material Iia
0.825/0.795 = 1.04
STRUCTURAL PARAMETERSOF THREE CARBONBLACKS Estimated
D L a (si.) Le (si.) dm (d.) Me
Furnex
Acetylene
0.205 12.0 12.0 3.53 3.40
0.09 15.0 13.6 3.55 3.83
0 21.9 19.0 3.55 5.34
0.015 .025 .02 .02 .015 .015 .Ol .Ol * 01 .01 .01 .01
0.07 .34 .23 .135 .115 .09 .02
Distribution of M values
1 2 3 4 5 6
7
Reference to Table I1 shows the appropriate value of La to be 12 A. It is important to notice that in the present analytical scheme no use is made of the breadth of the (10) reflection, as is the rule in the usual rapid procedures for determining crystallite dimensions from experimental line breadths. Experimental Results Table I11 presents the experimental findings for three representative blacks : Micronex-a Columbian channel black, Furnex-a Columbian furnace black, Acetylene-a Shawinigan black made by
Mioronex
0.02 1.0 0.3 .Ol .15
8 9 10 11 12
0.06 .29 .20 .14 .12 .095 .07 .025
0.05 .215 .12 .lo5 .09 .09 .08 .08
.07 .07 .02 01
.
Acknowledgment.-The authors are grateful to Dr. C. W. Sweitzer of Columbian Carbon Company for supplying the specimens and for his continued interest during the investigation. They acknowledge with thanks the assistance of Mr. D. T. Pitman with the experimental measurements.
STABILITY OF COPPER AND NICKEL CHELATES OF SOME PHTHALIC ACID DERIVATIVES* BY MOTOOYASUDA, KEINOSUKE SUZUKI AND KAZUO YAMASAKI Chemical Institute, Nagoya Univeraity, Nagoya, Japan Received July $0, 1066
+
The stabilit Constants have been measured in aqueous solutions at 26" for the complex M XC,H,(COO), = XCsHs(COO)*M, witi X equal to H, 3-N0z1~ N O Z341, , 3-Br, 4Br, 4OCHa and 4OCzH5, and M equal to Cu and Ni. Compared with phthalic acid, log kl and pK2 of Br, C1 and NO2 derivatives are smaller, while those of OCH, and OC,HI,me larger.
There is considerable work available concerning the dissociation constants of metal chelates of dicarboxylic acids. For example, Cannan and Kibrick,' and Topp and Davies2 determined the dissociation constants of dicarboxylat,es of bivalent metals such as Zn, Mg, Ca and Ba and found that
*
Presented a t the XV International Congreas of Pure and Applied Chemistry (Analytical Chemistry) held a t Lisbon in September, 1956. (1) R. K. Cannan and A. Kibrick, J . Am. Cham. Boc., Bo, 2314 (1938). (2) N. E. Topp and C. W. Daviea, J . Chem. BOG., 87 (1940).
the dissociation constants of the salts formed by a particular metal increased on passing along the series oxalate to adipate. Peacock and James8 also determined the dissociation constants of dicarboxylates of bivalent metals and came to a similar conclusion. Further, the result obtained by Riley4 revealed the infhences of alkyl substitution on the dissociation constant. But most of these results (3) J. M. Peacock and J. C. James, ibid., 2233 (1951). (4) E. L. Riley, ibid., 1642 (1930).
M. YASUDA, K. STJZUKI AND K. YAMASAKI
1650
were confined to zinc and alkaline earth metals. I n the present study the stability constants of copper and nickel chelates of phthalic acid and its 3- and 4-substituted derivatives are determined by pH method and the effects of substitution on the stability are examined. Experimental Reagents.-All the reagents used, including copper and nickel nitrates, sodium hydroxide and potassium biphthalate were chemicals of analytical grade. 3-Nitro- and 4-nitrophthalic acids, were prepared by nitration of phthalic acid. 3-Bromo- and 4-bromophthalic acids were synthesized by the method of Stephens,* and 3-chloro hthalic acid was prepared by diazotization of 3-aminop\thalic acid 4Methoxy- and 4-ethoxy hthalic acids were the products prepared by Katayama d f Co., Osaka. Measurement of pH.-Measurements of pH were made at 25' by a glass electrode combined with an electronic amplifier made by Mitamura & Co., Tokyo. Standardization of the apparatus was effected by suitable buffer solutions. Potassium nitrate was added to the solution to maintain the ioniC strength at 0.1. More concentrated solutions for nickel than for copper were used for the measurements and it was difficult to make measurements at a constant ionic strength. In this condition for nickel, therefore, the ionic strength was maintained at about 0.1 by nickel nitrate. itself without adding neutral salt, a8 the concentration of nickel ion participating in the chelate formation is very low. To convert the hydrogen ion activity into the concentration the value 0.83 suggested by Kielland' was used.
Results 1. Acid Dissociation Constants.-If phthalic acid and its derivatives are represented by HzA, the acid dissociation constants to be determined are and
where [ ] expresses concentration in mole/l. The dissociation constants were determined by titration with alkali and the values obtained are given in Table I. The first dissociation constants of 3-nitro, 4-nitrO and 3-chloro derivatives are considerably larger than the constant of phthalic acid and their accurate values were not determined by pH measurement. Therefore, the dissociation of the first step of these three compounds was assumed to be complete in a pH range larger than 4 and the stabilities TABLE I Ligand
PKI
P K ~
4.92 Phthalic acid' 2.76 2 3-Nitrophthalic acid
