Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ethyl Ether, Anhydrous (Diethyl Ether, Anhydrous) 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 Ethyl Ether, Anhydrous 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), Peroxide, Residue after Evaporation, Titrable Acid, Carbonyl Compounds, Alcohol, Water. Special caution is advised for the handling or testing of this substance.
(CH3CH2)2O
Formula Wt 74.12
CAS No. 60-29-7
C a u t i o n : Ethyl ether tends to form explosive peroxides, especially when anhydrous. It should not be allowed to evaporate to dryness or near dryness unless the absence of peroxides has been shown. The formation of peroxides is more rapid in ethyl ether kept in containers that have been opened and partly emptied. Some ethyl ether may contain a stabilizer. If it does, the amount and type should be marked on the label.
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . clear, colorless liquid Applications . . . . . . . . . . . . . . . . . . . . . . . . solvent; reagent in synthesis; extractant (hormones) from plant and animal tissues Change in state (approximate) . . . . . . . . . . . . boiling point, 34 °C Aqueous solubility . . . . . . . . . . . . . . . . . . . . 7 g in 100 mL at 20 °C Density . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.71
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% (CH3CH2)2O Maximum Allowable Color (APHA) . . . . . . . . . . . . . . . . . . . . . . . 10
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4138 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Peroxide (as H2O2). . . . . . Residue after evaporation . Titrable acid . . . . . . . . . Carbonyl (as HCHO) . . . . . Alcohol (CH3CH2OH) . . . . . Water (H2O) . . . . . . . . . .
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1 ppm 0.001% 0.0002 meq/g 0.001% Passes test 0.03%
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 Detector . . . . . . . . . . . . . . . . . . . . . . . . . TCD Measure the area under all peaks and calculate the ethyl ether content in area percent. Correct for water content.
Color (APHA) [Part 2: Measurement of Physical Properties; Color (APHA); Procedure for Color (APHA)].
Peroxide To 35.0 g (50 mL) of the ethyl ether in a separatory funnel, add 5.0 mL of titanium tetrachloride reagent solution. Shake vigorously, allow the layers to separate, and drain the lower layer into a 25 mL glass-stoppered graduated cylinder. For the standard, transfer 5.0 mL of titanium tetrachloride reagent solution to a similar graduated cylinder, and add a volume of solution containing 0.035 mg of hydrogen peroxide ion (H2O2) standard solution. Dilute both solutions with water to 10.0 mL, and mix. Allow the mixture to stand at least 30 min. Any yellow color in the solution of the sample should not exceed that in the standard. The color intensities may be determined with a spectrophotometer in 1 cm cells at a wavelength of 410 nm. Note: Fresh ethyl ether should meet this test, but after storage for several months, peroxide may be formed.
C a u t i o n : If peroxide is present, do not perform the test for residue after evaporation.
Residue after Evaporation [Part 2: Gravimetric Methods; Residue after Evaporation]. Evaporate 100.0 g (141 mL) to dryness in a tared, preconditioned dish on a water bath, and dry the residue at 105 °C for 30 min.
Titrable Acid
Note: Great care should be taken in the test during the addition of the sample and the titration to avoid contamination from carbon dioxide.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4138 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
To 10 mL of water in a glass-stoppered flask, add 0.10 mL of bromthymol blue indicator solution and 0.01 N sodium hydroxide until a blue color persists after vigorous shaking. Add 25 mL of sample from a pipette, and shake briskly to mix the two layers. If no blue color remains, titrate with 0.01 N sodium hydroxide until the blue color is restored and persists for several minutes. Not more than 0.30 mL of 0.01 N sodium hydroxide should be required.
Carbonyl Compounds Test solution preparation: Add 2.0 µL formaldehyde solution (37%), 1.4 µL acetaldehyde, 1.9 µL propionaldehyde, 1.9 µL acetone, 2.3 µL butyraldehyde, and 2.3 µL 2-butanone to 100.0 ml of the sample. (Molar equivalents to 10 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 inlet temperature and pressure to 90 °C and 20 kPa. Inject 3 µL of sample with a 5:1 split ratio. Oven temperature profile: isothermal at 35 °C for 40 min, 5 °C/min to 80 °C, hold 10 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.
Alcohol Transfer 100 mL to a separatory funnel, and shake with five successive portions—20 mL, 10 mL, 10 mL, 5 mL, and 5 mL, respectively—of distilled water at about 25 °C. Shake each portion for 2 min, and separate the water layer carefully. Finally, pour the combined water extract from one flask to another six times to ensure minimum contamination with ether. Transfer 1 mL of the water extract with a pipette to a comparison tube, and add 4 mL of water. For a standard take 5 mL of a solution of 0.2 mL of absolute alcohol in 1 L of water. Add 10 mL of nitrochromic acid solution (described below) to each solution, mix, and allow to stand for 1 h. At the end of this time, the color of the sample solution should show no more change from yellow to green or blue than is shown by the standard. The test and the standard must be kept at the same temperature. (Limit about 0.05%.)
For the Determination of Alcohol
N i t r o c h r o m i c A c i d S o l u t i o n . Mix 1 volume of 5% potassium chromate solution with 133 volumes of water and 66 volumes of colorless nitric acid. This reagent should not be used if more than 1 month old.
Water [Part 2: Titrimetric Methods; Water by the Karl Fischer Method; Coulometric Procedure; Coulometric Procedure for Samples Using Karl Fischer Reagent, Method 2]. Use 0.2 mL (0.14 g) of the sample.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4138 ACS Reagent Chemicals, Part 4
