Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Gallic 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
Downloaded by CORNELL UNIV on May 26, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4152
ABSTRACT This monograph for Gallic Acid 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, Residue after Ignition, and Sulfate.
C6H2(OH)3COOH (anhydrous) C6H2(OH)3COOH • H2O (monohydrate)
Formula Wt 170.12
CAS No. 149-91-7
Formula Wt 188.14
CAS No. 5995-86-8
Note: This reagent is available in both monohydrate and anhydrous forms. The label should identify the degree of hydration.
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . colorless solid Applications . . . . . . . . . . . . . . . . . . . . . . . . testing for free mineral acids, dihydroxyacetone, and alkaloids Change in state (approximate) . . . . . . . . . . . . sublimes at 210 °C, giving a stable form with melting point 258–265 °C and an unstable form with a melting point 225–230 °C Aqueous solubility . . . . . . . . . . . . . . . . . . . . 1 g in 87 mL
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4152 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.0% C6H2(OH)3COOH or C6H2(OH)3COOH · H2O
Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Residue after ignition. . . . . . . . . . . . . . . . . . 0.05% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.02%
TESTS Downloaded by CORNELL UNIV on May 26, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4152
Assay (By acid–base titrimetry). Weigh accurately about 0.7 g, transfer to a beaker, add 100 mL of water, and stir to dissolve. When dissolution is complete, titrate potentiometrically with 0.1 N sodium hydroxide. Correct for a blank determination. One milliliter of 0.1 N sodium hydroxide corresponds to 0.017012 g of C6H2(OH)3COOH or 0.018814 g of C6H2(OH)3COOH · H2O.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 10.0 g dissolved in 300 mL of water.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Ignite 4.0 g.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Dissolve 2.5 g in 50 mL of hot water, cool in ice water while stirring, and filter. Use 5 mL.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4152 ACS Reagent Chemicals, Part 4
