# Ethylamine

**Ethylamine** (IUPAC name ethanamine; also called aminoethane or monoethylamine) is a two-carbon primary aliphatic amine with the formula CH₃CH₂NH₂. It is a colorless gas or liquid with an ammonia-like odor, boiling at about 16.6 °C, and it is miscible with water.<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/6341)</sup><sup> • </sup><sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> Its principal industrial use is as an intermediate in the manufacture of triazine herbicides such as atrazine and simazine.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup>

| Key fact | Detail |
|---|---|
| Identity | Two-carbon primary aliphatic amine, CH₃CH₂NH₂; CAS 75-04-7; molecular weight 45.08 g/mol<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/6341)</sup> |
| Physical state | Colorless gas or water-white liquid below 62 °F (16.6 °C); miscible with water; vapor pressure 874 mmHg<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> |
| Basicity | Conjugate acid pKa 10.87; exists almost entirely as the ethylammonium cation at pH 5 to 9<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> |
| Main use | Production of triazine herbicides (including atrazine and simazine) by reaction with cyanuric chloride<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> |
| Production | Reaction of ethanol with ammonia over a hydrogenation catalyst; also from acetaldehyde, ethyl chloride, ethyl iodide, or nitroethane<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> |
| Occupational limits | NIOSH REL and OSHA PEL: TWA 10 ppm (18 mg/m³); IDLH 600 ppm<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> |
| Fire hazard | Flammable gas; explosive limits 3.5% to 14% by volume in air; flash point 1 °F<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> |
| Regulation | Ethylamine and its salts are a DEA List I chemical in the United States<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> |

## Physical properties

Ethylamine is a gas at ordinary room temperature and condenses to a water-white liquid below 62 °F (16.6 °C); it solidifies at about −80 °C.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup><sup> • </sup><sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> The liquid has a specific gravity of 0.69, so it is lighter than water, while its vapor is heavier than air with a relative gas density of 1.61.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> It is completely miscible with water, and the odor of the vapor ranges from fishlike to ammonia-like as the concentration increases.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup><sup> • </sup><sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/6341)</sup> The enthalpy of vaporization is about 29.0 kJ/mol near 282 K, falling to 25.9 kJ/mol at 392 K.<sup>[4](https://webbook.nist.gov/cgi/cbook.cgi?ID=C75047&Mask=2034&Units=SI)</sup>

Because the anhydrous compound boils just below room temperature, it is shipped as a liquefied compressed gas under [UN number](https://www.edgepedia.org/un-number) 1036, and it is also sold commercially as a 50–70% aqueous solution under UN number 2270.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup><sup> • </sup><sup>[5](https://inchem.org/documents/icsc/icsc/eics0153.htm)</sup>

## Basicity and reactivity

Ethylamine is a strong organic base. The pKa of its conjugate acid, the ethylammonium ion, is 10.87, which means that at pH values between 5 and 9 the compound exists almost entirely in the protonated cation form; for this reason, volatilization from water surfaces is not expected to be an important environmental fate process.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> In water it establishes the equilibrium

\[ \mathrm{CH_3CH_2NH_2 + H_2O \rightleftharpoons CH_3CH_2NH_3^{+} + OH^{-}} \]

and its base dissociation constant is about \( 5.6 \times 10^{-4} \) at 25 °C.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> Like ammonia, it reacts with acids to form salts such as ethylammonium chloride, and in the gas state it produces white fumes of the salt with hydrogen chloride.<sup>[6](https://chem.libretexts.org/Courses/Purdue/Purdue%3A_Chem_26200%3A_Organic_Chemistry_II_%28Wenthold%29/Chapter_20._Amines/20.03%3A_Basicity_of_amines/Amines_as_Bases)</sup>

The free base is corrosive and chemically aggressive. It reacts violently with acids and with strong oxidants, generating fire and explosion hazards, and it attacks many non-ferrous metals and plastics.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> NIOSH lists strong acids, strong oxidizers, copper, tin, and zinc in the presence of moisture, cellulose nitrate, chlorine, and hypochlorites as incompatibilities.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup>

## Production

The main industrial route is the reaction of ethanol with ammonia in the vapor phase under heat and pressure, in the presence of hydrogen and a hydrogenation catalyst such as nickel and copper on alumina.<sup>[7](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=910169ST.TXT)</sup> This reaction always produces a mixture of mono-, di-, and triethylamine; a large excess of ammonia favors the monoethylamine product, while recycling it increases the yield of the higher amines.<sup>[7](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=910169ST.TXT)</sup> In one described process, two moles of ethanol, one mole of ammonia, and three moles of hydrogen passed over the catalyst at 220 °C gave ethyl-, diethyl-, and triethylamines in a 1:5:3 ratio at 52% ethanol conversion.<sup>[7](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=910169ST.TXT)</sup>

Other routes recorded in the reference literature include reductive amination of acetaldehyde with ammonia and hydrogen over a hydrogenation catalyst, reaction of ethyl chloride with alcoholic ammonia under heat and pressure, reaction of ethyl iodide with liquid ammonia, and hydrogenation of [nitroethane](https://www.edgepedia.org/nitroethane).<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> BASF produces ethylamine from bioethanol, a renewable resource, and has patented processes that use fermentation-derived ethanol with ammonia over heterogeneous hydrogenation/dehydrogenation catalysts.<sup>[8](https://products.basf.com/global/en/ci/ethylamine-solution-70)</sup><sup> • </sup><sup>[9](https://patents.google.com/patent/US7642382)</sup>

## Uses

The principal use of monoethylamine is the production of triazine herbicides by reaction with cyanuric chloride; atrazine and simazine are named examples.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> It is also a chemical intermediate for ethylaminoethanol, 1,3-diethylthiourea (a corrosion inhibitor), 4-ethylmorpholine (a urethane foam catalyst), dimethylolethyltriazone (a wash-and-wear textile agent), and ethyl isocyanate.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> Other recorded uses include resin chemistry, dye and medicinal intermediates, solvent extraction, petroleum refining, detergents, and as a stabilizer for rubber latex.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> BASF lists mining chemicals, flotation agents such as isopropylethyl thiocarbamates, and use as a chain stopper controlling the degree of polymerization in polyurethane production.<sup>[8](https://products.basf.com/global/en/ci/ethylamine-solution-70)</sup> The Joint FAO/WHO Expert Committee on Food Additives classifies it as a flavoring agent, and it is naturally produced by the human body as an endogenous metabolite.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup>

Because ethylamine and its salts can serve in the manufacture of controlled substances, the United States Drug Enforcement Administration lists them as List I chemicals, a category for regulated chemicals with legitimate uses that are also important in illicit drug manufacture.<sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup>

## Safety

Ethylamine is a flammable gas with a flash point of 1 °F and explosive limits of 3.5% to 14% by volume in air; it presents a moderate explosion hazard when exposed to spark or flame.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup><sup> • </sup><sup>[3](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)</sup> A harmful concentration in air is reached very quickly on loss of containment, and rapid evaporation of the liquid can cause frostbite.<sup>[5](https://inchem.org/documents/icsc/icsc/eics0153.htm)</sup> Short-term exposure severely irritates the eyes and respiratory tract, and the liquid burns skin; the target organs are the eyes, skin, and respiratory system.<sup>[5](https://inchem.org/documents/icsc/icsc/eics0153.htm)</sup><sup> • </sup><sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup> [Combustion](https://www.edgepedia.org/combustion) produces toxic oxides of nitrogen.<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/6341)</sup>

Occupational exposure limits are a NIOSH recommended exposure limit and an OSHA permissible exposure limit of 10 ppm (18 mg/m³) as an 8-hour time-weighted average, an IDLH value of 600 ppm, and an ACGIH threshold limit value of 5 ppm as TWA with a 15 ppm short-term exposure limit (skin notation).<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup><sup> • </sup><sup>[5](https://inchem.org/documents/icsc/icsc/eics0153.htm)</sup> NIOSH specifies respirator protection up to 600 ppm and pressure-demand self-contained breathing apparatus for entry into unknown or IDLH concentrations.<sup>[2](https://www.cdc.gov/niosh/npg/npgd0263.html)</sup>

## Ethylamine in the interstellar medium

Ethylamine has a place in astrochemistry because primary amines share the NH₂ structural backbone of amino acids. In 2021, researchers reported a tentative interstellar detection of ethylamine toward the Galactic Centre molecular cloud G+0.693-0.027, in the [Sagittarius B2](https://www.edgepedia.org/sagittarius-b2) complex, with an abundance relative to H₂ of \( (1.9 \pm 0.5) \times 10^{-10} \) and an abundance ratio to methylamine of about 0.008.<sup>[10](https://arxiv.org/abs/2110.01791)</sup> The detection was classified as tentative because the clean spectral transitions were weak, with a signal-to-noise ratio of 4 in integrated intensity.<sup>[10](https://arxiv.org/abs/2110.01791)</sup> [Laboratory](https://www.edgepedia.org/laboratory) work on interstellar ice analogs has also found tentative formation of ethylamine when C₂H₂ ice photodissociation products react with NH₂ radicals and hydrogen atoms, and theoretical studies of its binding energy on water ice inform models of where such amines condense in protoplanetary disks.<sup>[11](https://arxiv.org/abs/2405.07855)</sup><sup> • </sup><sup>[12](https://arxiv.org/abs/2406.16952)</sup>

## References

1. [Ethylamine, CID 6341, PubChem, National Library of Medicine](https://pubchem.ncbi.nlm.nih.gov/compound/6341)
2. [Ethylamine, NIOSH Pocket Guide to Chemical Hazards, CDC](https://www.cdc.gov/niosh/npg/npgd0263.html)
3. [Ethylamine, HSDB content in PubChem CID 6341](https://pubchem.ncbi.nlm.nih.gov/compound/ethyl-amine)
4. [Ethylamine, phase-change data, NIST Chemistry WebBook, SRD 69](https://webbook.nist.gov/cgi/cbook.cgi?ID=C75047&Mask=2034&Units=SI)
5. [ICSC 0153: Ethylamine, ILO-WHO International Chemical Safety Cards](https://inchem.org/documents/icsc/icsc/eics0153.htm)
6. [Amines as Bases, Chemistry LibreTexts](https://chem.libretexts.org/Courses/Purdue/Purdue%3A_Chem_26200%3A_Organic_Chemistry_II_%28Wenthold%29/Chapter_20._Amines/20.03%3A_Basicity_of_amines/Amines_as_Bases)
7. [Industrial Process Profiles for Environmental Use: Chapter 6, The Industrial Organic Chemicals Industry, US EPA](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=910169ST.TXT)
8. [Ethylamine solution 70%, BASF product page](https://products.basf.com/global/en/ci/ethylamine-solution-70)
9. [US7642382B2: Processes for preparing ethylamines, Google Patents](https://patents.google.com/patent/US7642382)
10. [Zeng, S. et al. (2021). Probing the chemical complexity of amines in the ISM: detection of vinylamine and tentative detection of ethylamine. arXiv.](https://arxiv.org/abs/2110.01791)
11. [Formation of N-bearing complex organic molecules in molecular clouds via UV photolysis of C₂H₂ ice. arXiv.](https://arxiv.org/abs/2405.07855)
12. [Binding energies of ethanol and ethylamine on interstellar water ices. arXiv.](https://arxiv.org/abs/2406.16952)

---
*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Organic substances › Amines and nitrogen functional groups › Aliphatic amines and polyamines › Aliphatic amines overview*

*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license