Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Borohydride (Sodium Tetrahydroborate) 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 Sodium Borohydride 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.
NaBH4
Formula Wt 37.83
CAS No. 16940-66-2
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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hygroscopic solid reducing agent decomposes at 400–500 °C 55% (w/w) at 25 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥98% NaBH4
TESTS Assay (By titration of reductive capacity). Weigh accurately about 0.5 g of sample and dissolve in 125 mL of dilute sodium hydroxide solution (1:24) in a 250 mL volumetric flask. Dilute with the sodium hydroxide solution to volume, and mix. Pipette 10.0 mL of the sample solution into a 250 mL iodine flask, add 30.0 mL of 0.3 N potassium iodate volumetric solution, and mix. Add 2 g of potassium iodide, mix, and then add 10 mL of 10% sulfuric acid. Insert the stopper in the flask, and allow to stand in the dark for 3 min. Titrate with 0.1 N sodium thiosulfate volumetric solution to a colorless end point,
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4334 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
adding 3 mL of starch indicator solution near the end point. One milliliter of 0.3 N potassium iodate consumed corresponds to 0.00149 g of NaBH4.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4334 ACS Reagent Chemicals, Part 4
