Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Imidazole (1,3-Diazole)
Downloaded by CORNELL UNIV on May 8, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4172
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 Imidazole 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, pH of a 5% Solution at 25.0 °C, Residue after Ignition, Iron, and Water.
NHCH:NCH:CH
Formula Wt 68.08
CAS No. 288-32-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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solid Karl Fischer reagent melting point, 90 °C freely soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99% C3H4N2 pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 9.5–11.0 Maximum Allowable Residue after ignition. . . . . . . . . . . . . . . . . . 0.1% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 0.2%
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4172 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 0.15 g, and dissolve in 25 mL of glacial acetic acid. Titrate with 0.1 N perchloric acid in acetic acid volumetric solution, using 0.1 mL of crystal violet indicator solution. One milliliter of 0.1 N perchloric acid corresponds to 0.006808 g of C3H4N2. Correct for a blank.
Downloaded by CORNELL UNIV on May 8, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4172
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Use 1.0 g.
Iron (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Iron
S a m p l e S t o c k S o l u t i o n . Dissolve 25.0 g of sample with water in a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.25 g).
For the Determination of Iron
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Fe
248.3
5.0
0.05; 0.10
A/A
No
*A/A is air/acetylene.
Water [Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Volumetric Procedure; Volumetric Procedure for Samples Using Karl Fischer Reagent, Method 1]. Use 2.0 g of sample.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4172 ACS Reagent Chemicals, Part 4
