Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Pyridine 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 Pyridine 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, Solubility in Water, Residue after Evaporation, Water, Chloride, Sulfate, Ammonia, Copper, and Reducing Substances.
C5H5N
Formula Wt 79.10
CAS No. 110-86-1
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . . Density . . . . . . . . . . . . . . . .
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clear liquid solvent; complexing agent boiling point, 116 °C miscible 0.98
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . >99.0% C5H5N Solubility in water . . . . . . . . . . . . . . . . . . . . Passes test Maximum Allowable Residue after evaporation . . . . . . . . . . . . . . . 0.002% Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 0.1% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.001%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4313 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Ammonia (NH3) . . . . . . . . . . . . . . . . . . . . . . 0.002% Copper (Cu) . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Reducing substances . . . . . . . . . . . . . . . . . . Passes test
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 Measure the area under all peaks, and calculate the pyridine content in area percent. Correct for water content.
Solubility in Water Dilute 10 mL with 90 mL of water. The solution should show no turbidity in 30 min.
Residue after Evaporation [Part 2: Gravimetric Methods; Residue after Evaporation]. Evaporate 50 g (51 mL) to dryness in a preconditioned dish on a hot plate (~100 °C), and dry the residue at 105 °C for 30 min. Save residue after weighing for the test for copper.
Water [Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Volumetric Procedure; Volumetric Procedure for Samples Using Karl Fischer Reagent, Method 1]. Use 20 mL (19.6 g) of the sample.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Dilute 1.0 g (1.0 mL) with water to 25 mL.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 3].
Ammonia Add 2 g (2.0 mL) to 10 mL of carbon dioxide-free water. Add 0.10 mL of phenolphthalein indicator solution. If a pink color develops, it should be discharged by not more than 0.24 mL of 0.01 N hydrochloric acid.
Copper (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]). Add 5 mL of nitric acid to the residue from the test for residue after evaporation, and digest on a hot plate (~100 °C) for about 5 min. Cool, and add 25 mL of water. Transfer to a 50 mL volumetric flask, dilute to the mark with water, and mix (1 mL = 1.0 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4313 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Cu
324.8
5.0
0.025; 0.05
A/A
Yes
*A/A is air/acetylene.
Reducing Substances To 5 g (5.0 mL), add 0.50 mL of 0.1 N potassium permanganate volumetric solution. The pink color should not be entirely discharged in 30 min. If a brown color interferes, the solution should be centrifuged or filtered through a sintered glass filter. If a pink color persists, the sample passes.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4313 ACS Reagent Chemicals, Part 4
