Monograph pubs.acs.org/doi/book/10.1021/acsreagents
para-Toluenesulfonic Acid Monohydrate (4-Methylbenzenesulfonic Acid Monohydrate) 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 para-Toluenesulfonic Acid Monohydrate provides, in addition to common physical constants, a general description including typical appearance, applications, 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, Water, Clarity of Solution, Residue after Ignition, Sulfate, Heavy Metals, Iron and Sodium.
CH3C6H4SO3H • H2O
Formula Wt 190.21
CAS No. 6192-52-5
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . solid Applications . . . . . . . . . . . . . . . . . . . . . . . . derivatizing agent Aqueous solubility . . . . . . . . . . . . . . . . . . . . freely soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98.5% CH3C6H4SO3H · H2O Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 9.5–11.5% Maximum Allowable Clarity of solution . . . . . . . . . . . . . . . . . . . . Passes test Residue after ignition. . . . . . . . . . . . . . . . . . 0.1% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.3% Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4410 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 0.8 g, dissolve in 100 mL of water, add 0.10 mL of phenolphthalein indicator solution, and titrate with 0.1 N sodium hydroxide volumetric solution to a pink end point. One milliliter of 0.1 N sodium hydroxide corresponds to 0.01902 g of CH3C6H4SO3H · H2O.
Water [Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Volumetric Procedure; Volumetric Procedure for Samples Using Karl Fischer Reagent, Method 1]. Use 0.5 g.
Clarity of Solution Dissolve 10 g in 50 mL of water. The solution should be clear and colorless.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Use 5.0 g. Retain the residue for the test for heavy metals.
Sulfate Dissolve 0.70 g in 180 mL of water, add 10 mL of hydrochloric acid, and heat to boiling. Add 10 mL of 12% barium chloride reagent solution, digest in a covered beaker on a hot plate (~100 °C) for 2 h, and allow to stand for at least 8 h. If a precipitate is formed, filter, wash thoroughly, and ignite. The weight of the precipitate should not be more than 0.005 g greater than the weight obtained from a blank test prepared concomitantly.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve the residue from the test for residue after ignition with a mixture of 2 mL of nitric acid and 4 mL of hydrochloric acid, and evaporate to dryness on a hot plate (~100 °C). Take up the residue with 1 mL of dilute hydrochloric acid (1:1) and 8 mL of hot water. Cool, and dilute to 50 mL with water. Use 20 mL of this solution.
Iron and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Iron and Sodium
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g in water, and dilute with water to 100 mL (1 mL = 0.10 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4410 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Iron and Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Fe
248.3
1.0
0.05; 0.10
A/A
Yes
Na
589.0
0.50
0.005; 0.01
A/A
No
*A/A is air/acetylene.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4410 ACS Reagent Chemicals, Part 4
