Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Acetaldehyde (Ethanal)
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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 Acetaldehyde provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), aqueous solubility, and density. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Residue after Evaporation, and Titrable Acid.
CH3CHO
Formula Wt 44.05
CAS No. 75-07-0
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . . Density . . . . . . . . . . . . . . . .
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liquid with pungent odor standard in chromatography and polarography boiling point, 21 °C miscible with water 0.79
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.5% CH3CHO Maximum Allowable Residue after evaporation . . . . . . . . . . . . . . . 0.005% Titrable acid . . . . . . . . . . . . . . . . . . . . . . . 0.008 meq/g
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4001 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay Analyze the sample by gas chromatography using the general parameters cited in [Part 2: Chromatography; Recommended Procedures; Gas Chromatography]. The following specific conditions are also required. Column . . . . . . . . . . . . . . . . . . . . . . . . . . Type I, methyl silicone Detector . . . . . . . . . . . . . . . . . . . . . . . . . Flame ionization Measure the area under all peaks, and calculate the area percent for acetaldehyde.
Residue after Evaporation
Downloaded by CORNELL UNIV on May 20, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4001
[Part 2: Gravimetric Methods; Residue after Evaporation]. Evaporate 40 g (51 mL) to dryness in a tared, preconditioned platinum dish on a hot plate (~100 °C) in a well-ventilated hood, and dry the residue at 105 °C for 30 min.
Titrable Acid Work in a fume hood. Chill 25 g (32 mL) of sample in a graduated cylinder in an ice bath. To a 250 mL Erlenmeyer flask, add about 25 mL of deionized water and 75 g of deionized ice. Add 0.5 mL of phenolphthalein indicator solution, and titrate with 0.1 N sodium hydroxide to the first perceptible pink color that persists for 15 s. Add the chilled sample and titrate immediately to the same faint pink color. Not more than 2.0 mL of 0.1 N sodium hydroxide should be required.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4001 ACS Reagent Chemicals, Part 4
