Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Calcium Acetate Monohydrate Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
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ABSTRACT This monograph for Calcium Acetate Monohydrate provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble Matter, Alkalinity, Titrable Acid, Chloride, Sulfate, Barium, Heavy Metals, Iron, Magnesium, Potassium, Sodium, and Strontium.
Ca(CH3COO)2·H2O
Formula Wt 176.18
CAS No. 5743-26-0
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . odorless, colorless solid Applications . . . . . . . . . . . . . . . . . . . . . . . . precipitation of oxalates Change in state (approximate) . . . . . . . . . . . . melting point, above 160 °C, decomposes to form acetone and calcium carbonate Aqueous solubility . . . . . . . . . . . . . . . . . . . . 34.7 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% Ca(CH3COO)2 · H2O Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . Passes test Titrable acid . . . . . . . . . . . . . . . . . . . . . . . 0.035 meq/g Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Barium (Ba) . . . . . . . . . . . . . . . . . . . . . . . . 0.01% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.005% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.05%
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4075 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.02% Strontium (Sr) . . . . . . . . . . . . . . . . . . . . . . 0.05%
TESTS Assay
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(By complexometric titration for calcium). Weigh accurately 0.70 g, transfer to a 250 mL beaker, and dissolve in 150 mL of water. While stirring, add from a 50 mL burette about 30 mL of 0.1 M EDTA volumetric solution. Add 10% sodium hydroxide reagent solution until the pH is above 12 (using a pH meter). Add about 300 mg of hydroxynaphthol blue indicator mixture, and continue the titration with the 0.1 M EDTA to a blue color. One milliliter of 0.1 M EDTA corresponds to 0.01762 g of Ca(CH3COO)2·H2O.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 200 mL of water.
Alkalinity and Titrable Acid Dissolve 2.0 g in 25 mL of carbon dioxide-free water, and add 0.10 mL of phenolphthalein indicator solution. The sample solution should show no pink color due to excess alkalinity. If the sample solution does exhibit a pink color, titrate the solution with 0.1 N hydrochloric acid until clear. Not more than 0.70 mL of 0.1N hydrochloric acid should be required. If the sample solution does not exhibit a pink color, titrate the solution with 0.10 N sodium hydroxide until a pink color is produced after shaking. Not more than 0.70 mL of 0.10 N sodium hydroxide should be required in the titration.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Dissolve 1.0 g in 20 mL of water.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Use 0.50 g.
Barium Dissolve a 5.0 g sample in water and dilute to 25.0 mL (sample solution). For the sample, add 2 g of sodium acetate and 0.05 mL of glacial acetic acid to 15 mL of the sample solution. Dilute to 25 mL with water, filter if necessary. For the control, add 2 g of sodium acetate, 0.05 mL of glacial acetic acid, and 0.2 mg of barium to 5 mL of the sample solution, and dilute to 25 mL with water. To each solution, add 2 mL of 10% potassium dichromate reagent solution, and allow to stand for 15 min. Any turbidity in the solution of the sample should not exceed that in the control.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 0.40 g in 20 mL of water.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4075 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Dissolve 1.0 g in 20 mL of water.
Magnesium, Potassium, Sodium, and Strontium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Magnesium, Potassium, Sodium, and Strontium
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S a m p l e S t o c k S o l u t i o n . Dissolve 2.0 g in 80 mL of water containing 2 mL of nitric acid. Transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.02 g).
For the Determination of Magnesium, Potassium, Sodium, and Strontium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Mg
285.2
0.02
0.01; 0.02
A/A
Yes
Na
589.0
0.05
0.01; 0.02
A/A
No
K
766.5
0.20
0.02; 0.04
A/A
No
Sr
460.7
0.20
0.10; 0.20
N/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
C
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4075 ACS Reagent Chemicals, Part 4
