Monograph pubs.acs.org/doi/book/10.1021/acsreagents
tert-Butyl Alcohol (2-Methyl-2-propanol) 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 tert-Butyl Alcohol 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, Titrable Acid, Carbonyl Compounds, and Water.
(CH3)3COH
Formula Wt 74.12
CAS No. 75-65-0
Note: Because the melting point of this reagent is close to 25 °C, the sample may be warmed to about 30 °C for testing.
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . . Density . . . . . . . . . . . . . . . .
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© 2017 American Chemical Society
colorless solid solvent melting point, 25 °C; boiling point, 82 °C soluble 0.79
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DOI:10.1021/acsreagents.4069 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% (CH3)3COH Maximum Allowable Color (APHA) . . . . . . . . . . . . . . . . . . . . . . . 20 Residue after evaporation . . . . . . . . . . . . . . . 0.003% Titrable acid . . . . . . . . . . . . . . . . . . . . . . . 0.001 meq/g Carbonyl compounds (as formaldehyde) . . . . . . 0.01% Water (H2O) . . . . . . . . . . . . . . . . . . . . . . . . 0.1%
TESTS Assay Analyze the sample by gas chromatography using the parameters cited in [Part 2: Chromatography; Recommended Procedures; Gas Chromatography]. The following specific conditions are also required. Column . . . . . . . . . . . . . . . . . . . . . . . . . . Type I, methyl silicone Measure the areas under all peaks, and calculate the tert-butyl alcohol content in area percent. Correct for water content.
Color (APHA) [Part 2: Measurement of Physical Properties; Color (APHA); Procedure for Color (APHA)].
Residue after Evaporation [Part 2: Gravimetric Methods; Residue after Evaporation]. Evaporate 60 g (77 mL) of sample to dryness in a tared, preconditioned evaporating dish on a hot plate (~100 °C), and dry the residue at 105 °C for 30 min.
Titrable Acid To 35 g (45 mL) in a glass-stoppered Erlenmeyer flask, add 0.15 mL of phenolphthalein indicator solution, and shake for 1 min. No pink color should appear. Titrate the solution with 0.01 N methanolic potassium hydroxide to a faint pink color that persists for at least 15 s. Not more than 3.5 mL of 0.01 N methanolic potassium hydroxide should be required.
Carbonyl Compounds If the t-butyl alcohol is solid, a mixture of 2.5 mL dioxane and 97.5 mL t-butyl alcohol may be prepared (warming the alcohol to liquefy it, if necessary) in order to keep it liquid during analysis. Note that the 1,4-dioxane used must meet the carbonyl specification of less than 100 ppm. If this is done, the user should adjust the specification limit accordingly to account for the added 1,4-dioxane. Test solution preparation: Add 19.7 µL formaldehyde solution (37%), 14.6 µL acetaldehyde, 18.9 µL propionaldehyde, 19.3 µL acetone, 23.1 µL butyraldehyde, and 23.4 µL 2-butanone to 100.0 mLl of the sample. (Molar equivalents to 100 µg/g formaldehyde added). 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 the inlet temperature and pressure to 120 °C and 164 kPa. Inject 5 µL of sample with a 5:1 split ratio. The oven temperature profile is isothermal at 40 °C for 20 min, 5 °C/min to 90 °C, hold 1 min, 40 °C/min to 220 °C, hold 5.75 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 or no greater than 49.4% if the alcohol–dioxane mixture is used.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4069 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Water [Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Volumetric Procedure; Volumetric Procedure for Samples Using Karl Fischer Reagent, Method 1]. Use 45 mL (35 g) of the sample.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4069 ACS Reagent Chemicals, Part 4
