Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Chloroacetic Acid (Monochloroacetic Acid; Chloroethanoic Acid) 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
ABSTRACT This monograph for Chloroacetic Acid provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), aqueous solubility, density, and pKa. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble Matter, Residue after Ignition, Chloride, Sulfate, Heavy Metals, Iron, and Substances Darkened by Sulfuric Acid.
ClCH2COOH
Formula Wt 94.50
CAS No. 79-11-8
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . colorless or white deliquescent solid Applications . . . . . . . . . . . . . . . . . . . . . . . . preparation of metal derivatives Change in state (approximate) . . . . . . . . . . . . exists in α, β, and γ forms, with melting points of 63 °C, 55–56 °C, and 50 °C, respectively Aqueous solubility . . . . . . . . . . . . . . . . . . . . very soluble Density . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.58 pKa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% ClCH2COOH Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Residue after ignition. . . . . . . . . . . . . . . . . . 0.02% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.02% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001%
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4089 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.002% Substances darkened by sulfuric acid . . . . . . . . Passes test
TESTS Assay (By acid–base titrimetry). Weigh accurately about 3 g, transfer to a conical flask, and dissolve in about 50 mL of water. Add 0.15 mL of phenolphthalein indicator solution, and titrate with 1 N sodium hydroxide volumetric solution. One milliliter of 1 N sodium hydroxide corresponds to 0.0945 g of ClCH2COOH.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10 g in 100 mL of water.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Use 5.0 g. Retain the residue for the test for iron.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 0.1 g.
Sulfate Dissolve 5.0 g in 30 mL of water, add 25 mg of anhydrous sodium carbonate, evaporate to dryness, and heat over a low flame until the chloroacetic acid is volatilized. Dissolve the residue in 50 mL of water, and neutralize with hydrochloric acid. Filter if necessary, wash, and dilute with water to 100 mL. To 5 mL (0.25 g sample), add 1 mL of dilute hydrochloric acid (1:19). Dilute to 10 mL, and add 1 mL of 12% barium chloride reagent solution. Any turbidity produced in the sample solution after 10 min should not exceed that produced by 0.05 mg of sulfate ion (SO4) in an equal volume of solution containing the quantities of reagents used in the test.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 5.0 g in 30 mL of water, neutralize with (1:1) ammonium hydroxide, and dilute with water to 50 mL. For the test solution, use 30 mL. For the standard–control solution, add 0.02 mg of lead to 10 mL.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. To the residue after ignition, add 3 mL of hydrochloric acid, cover with a watch glass, and digest on a hot plate (~100 °C) for 15 min. Remove the cover, and evaporate to dryness. Dissolve the residue with 1 mL of hydrochloric acid and dilute with water to 100 mL. Use 10 mL (0.5 g sample) as the sample solution.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4089 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Substances Darkened by Sulfuric Acid Heat 1.0 g with 10 mL of 95.0 ± 0.5% sulfuric acid at 50 °C for 5 min. The solution should not have more than a faintly brown color.
© 2017 American Chemical Society
C
DOI:10.1021/acsreagents.4089 ACS Reagent Chemicals, Part 4
