Monoethanolamine

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₂H₇NO 61.08

Ethanol, 2-amino-;

2-Aminoethanol CAS RN^®: 141-43-5.

1 DEFINITION

Monoethanolamine contains NLT 98.0% and NMT 100.5% by weight of monoethanolamine (C₂H₇NO).

2 IDENTIFICATION

Change to read:

A. ASPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197F (CN 1-MAY-2020)

3 ASSAY

3.1 PROCEDURE

Sample solution: Weigh a glass-stoppered weighing bottle containing 25 mL of water. Add 1 g of Monoethanolamine, and reweigh.

Blank: 25 mL of water

Titrimetric system

(See Titrimetry (541).)

Mode: Direct titration

Titrant: 0.5 N hydrochloric acid VS

Endpoint detection: Visual

Analysis: Transfer the Sample solution to a suitable flask, add a mixed indicator of 5 parts bromocresol green TS and 6 parts methyl red TS for a total of approximately 11 parts of solution. Titrate the Sample solution with Titrant. Perform a blank determination.

Calculate the percentage of monoethanolamine (C₂H₇NO) in the portion of sample taken:

Result = {[(V_S - V_B) x N x F/W} × 100

V_S = Titrant volume consumed by the Sample solution (mL)

V_B = Titrant volume consumed by the Blank (mL)

N = actual normality of the Titrant (mEq/mL)

F = equivalency factor, 61.08 mg/mEq

W = sample weight (mg)

Acceptance criteria: 98.0%-100.5%

4 IMPURITIES

RESIDUE ON IGNITION (281): NMT 0.1%

5 SPECIFIC TESTS

SPECIFIC GRAVITY (841): 1.013-1.016

DISTILLING RANGE, Method II (721): NLT 95% of it distills between 167° and 173°, a correction factor of 0.052° per mm applied as necessary.

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant containers.

USP REFERENCE STANDARDS (11)

USP Monoethanolamine RS