Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium Benzoate (Benzoic Acid, Ammonium Salt) 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 Ammonium Benzoate 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, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Residue after Ignition, Substances Reducing Permanganate, Chlorine Compounds, Heavy Metals, and Iron.
C7H9NO2
Formula Wt 139.15
CAS No. 1863-63-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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solid determination of benzoate stabilizers in feeds melting point, 198 °C very soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.0% C7H9NO2 pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 5.0–8.0 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Residue after ignition. . . . . . . . . . . . . . . . . . 0.005% Substances reducing permanganate . . . . . . . . . Passes test
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4017 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Chlorine compounds (as Cl) . . . . . . . . . . . . . . 0.01% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001%
TESTS Assay (By alkalimetry for ammonium). Weigh accurately about 5.0 g of sample, and dissolve in 50 mL of water in a 500 mL Erlenmeyer flask. Add exactly 50.0 mL of 1 N sodium hydroxide, place a filter funnel loosely in the neck of the flask, and boil until all the ammonia is expelled (about 10–15 min) as determined with litmus paper. Cool, and add 0.15 mL of thymol blue indicator solution. Titrate the excess sodium hydroxide with 1 N sulfuric acid. One milliliter of 1 N sodium hydroxide corresponds to 0.13916 g of C7H9NO2.
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20.0 g in 200 mL of water.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Heat 20.0 g in a preconditioned platinum dish at a temperature sufficient to volatilize. When volatilized, cool and continue as described.
Substances Reducing Permanganate Add 1.0 g of the sample to 10 mL of water. Add 0.2 mL of 0.1 N potassium permanganate, and let stand for 5 min. The pink color should not be entirely discharged.
Chlorine Compounds Mix 1.0 g with 0.5 g of sodium carbonate, and add 10–15 mL of water. Evaporate and ignite until charred. Extract with 20 mL of water and 5.5 mL of nitric acid. Filter through a chloride-free filter, and wash with two 10 mL portions of water. Dilute with water to 100 mL. Use 10 mL for the test. Continue as in the test for chloride, [Part 2: Colorimetry and Turbidimetry; Chloride].
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Volatilize 2.0 g over a low flame, cool, and add 5 mL of nitric acid and 10 mg of sodium carbonate. Evaporate to dryness on a hot plate (~100 °C), dissolve the residue in water, and dilute to 25 mL. For the control, add 0.02 mg of lead to 5 mL of nitric acid and 10 mg of sodium carbonate, and evaporate on a hot plate. Dissolve the residue, and dilute to 25 mL.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4017 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 2 (Hydroxylamine and 1,10-Phenanthroline)]. Use 1.0 g.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4017 ACS Reagent Chemicals, Part 4
