Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Propionic Acid (Propanoic Acid)
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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 Propionic Acid 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, Color (APHA), Residue after Evaporation, Readily Oxidizable Substances, Heavy Metals, Carbonyl Compounds, and Water.
C3H6O2
Formula Wt 74.08
CAS No. 79-09-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . . Density . . . . . . . . . . . . . . . .
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liquid esterifying agent boiling point, 141 °C miscible 0.99
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.5% CH3CH2COOH Maximum Allowable Color (APHA) . . . . . . . . . . . . . . . . . . . . . . . 20 Residue after evaporation . . . . . . . . . . . . . . . 0.01% Readily oxidizable substances (as HCOOH). . . . . 0.10% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Carbonyl compounds (formaldehyde, acetone, or acetaldehyde, or propionaldehyde) . . . . . . . . . 0.002% Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 0.15%
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4311 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By acid–base titrimetry). Weigh accurately about 3.0 g, and dissolve in 100 mL of water. Add 0.15 mL of phenolphthalein indicator solution, and titrate with 1 N sodium hydroxide volumetric solution to the first appearance of a faint pink end point that persists for at least 30 s. One milliliter of 1 N sodium hydroxide corresponds to 0.07408 g of CH3CH2COOH.
Color (APHA) Downloaded by CORNELL UNIV on June 8, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4311
[Part 2: Measurement of Physical Properties; Color (APHA); Procedure for Color (APHA)].
Residue after Evaporation [Part 2: Gravimetric Methods; Residue after Evaporation]. Evaporate 20 g (20 mL) to dryness in a tared, preconditioned dish on a hot plate (~100 °C), and dry the residue at 105 °C for 30 min.
Readily Oxidizable Substances Dissolve 7.5 g of sodium hydroxide in 50 mL of water, cool, add 3 mL of bromine water, stir until dissolved, and dilute to 1 L with water. Transfer 25.0 mL of this solution to a glass-stoppered conical flask containing 100 mL of water, and add 10 mL of a 20 wt % solution of sodium acetate trihydrate and 10.0 mL of the sample. Allow to stand for 15 min, then add 1.0 g of potassium iodide dissolved in 5 mL of water, mix, and add 10 mL of hydrochloric acid. Titrate with 0.1 N sodium thiosulfate volumetric solution just to the disappearance of the brown color. Perform a blank determination. One milliliter of 0.1 N sodium thiosulfate corresponds to 0.004603 g of formic acid (HCOOH). The difference between the blank and sample titrations should not exceed 2.2 mL.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Add about 25 mg of sodium carbonate to 3.0 g of the sample in a platinum dish, and evaporate to dryness on a hot plate (~100 °C). Dissolve the residue in 1 mL of dilute hydrochloric acid (1:19), and dilute with water to 30 mL. Use 25 mL to prepare the sample solution, and use the remaining 5 mL to prepare the control solution.
Carbonyl Compounds Test solution preparation: Add 4.9 μL formaldehyde, 2.5μL each acetaldehyde and acetone, and 2.44 μL propionaldehyde to 100 mL of the propionic acid sample. Analyze the sample and the test solution by GC–MS according to the procedure in [Part 2: Chromatography; Gas Chromatography–Mass Spectrometry]. For the column in [Part 2: Chromatography; Gas Chromatography–Mass Spectrometry], set inlet temperature and pressure to 120 °C and 164 kPa. Inject 1 μL of sample with a 5:1 split ratio. Oven temperature profile: isothermal at 60 °C for 5 min, 10 °C/min to 90 °C, 40 °C/min to 130 °C, hold 5 min, 40 °C/min to 230 °C, hold 3.5 min. The area of each of the carbonyl peaks in the sample should be no greater than half that of the corresponding peak in the test solution.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4311 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Water
Downloaded by CORNELL UNIV on June 8, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4311
[Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Volumetric Procedure; Volumetric Procedure for Samples Using Karl Fischer Reagent, Method 1]. Use 10.0 mL (9.9 g) of the sample.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4311 ACS Reagent Chemicals, Part 4
