Ethylamine

Ethylamine, also known as ethanamine, is an organic compound with the formula CH3CH2NH2. This colourless gas has a strong ammonia-like odor. It condenses just below room temperature to a liquid miscible with virtually all solvents. It is a nucleophilic base, as is typical for amines. Ethylamine is widely used in chemical industry and organic synthesis.[4]

Ethylamine[1]
Skeletal formula of ethylamine
Skeletal formula of ethylamine
Skeletal formula of ethylamine with all explicit hydrogens added
Skeletal formula of ethylamine with all explicit hydrogens added
Ball and stick model of ethylamine
Ball and stick model of ethylamine
Spacefill model of ethylamine
Spacefill model of ethylamine
Names
Preferred IUPAC name
Ethanamine
Other names
Ethylamine
Identifiers
3D model (JSmol)
3DMet
505933
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.759
EC Number
  • 200-834-7
897
KEGG
MeSH ethylamine
RTECS number
  • KH2100000
UNII
UN number 1036
  • InChI=1S/C2H7N/c1-2-3/h2-3H2,1H3 checkY
    Key: QUSNBJAOOMFDIB-UHFFFAOYSA-N checkY
  • CCN
Properties
C2H7N
Molar mass 45.085 g·mol−1
Appearance Colourless gas
Odor fishy, ammoniacal
Density 688 kg m−3 (at 15 °C)
Melting point −85 to −79 °C; −121 to −110 °F; 188 to 194 K
Boiling point 16 to 20 °C; 61 to 68 °F; 289 to 293 K
Miscible
log P 0.037
Vapor pressure 116.5 kPa (at 20 °C)
350 μmol Pa−1 kg−1
Acidity (pKa) 10.8 (for the Conjugate acid)
Basicity (pKb) 3.2
Thermochemistry
−57.7 kJ mol−1
Hazards
GHS labelling:
GHS02: Flammable GHS07: Exclamation mark
Danger
H220, H319, H335
P210, P261, P305+P351+P338, P410+P403
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
3
4
0
Flash point −37 °C (−35 °F; 236 K)
383 °C (721 °F; 656 K)
Explosive limits 3.5–14%
Lethal dose or concentration (LD, LC):
  • 265 mg kg−1 (dermal, rabbit)
  • 400 mg kg−1 (oral, rat)
1230 ppm (mammal)[2]
3000 ppm (rat, 4 hr)
4000 ppm (rat, 4 hr)[2]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 10 ppm (18 mg/m3)[3]
REL (Recommended)
 TWA 10 ppm (18 mg/m3)[3]
IDLH (Immediate danger)
 600 ppm[3]
Related compounds
Related alkanamines
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Infobox references

Synthesis

Ethylamine is produced on a large scale by two processes. Most commonly ethanol and ammonia are combined in the presence of an oxide catalyst:

CH3CH2OH + NH3 → CH3CH2NH2 + H2O

In this reaction, ethylamine is coproduced together with diethylamine and triethylamine. In aggregate, approximately 80M kilograms/year of these three amines are produced industrially.[4] It is also produced by reductive amination of acetaldehyde.

CH3CHO + NH3 + H2 → CH3CH2NH2 + H2O

Ethylamine can be prepared by several other routes, but these are not economical. Ethylene and ammonia combine to give ethylamine in the presence of a sodium amide or related basic catalysts.[5]

H2C=CH2 + NH3 → CH3CH2NH2

Hydrogenation of acetonitrile, acetamide, and nitroethane affords ethylamine. These reactions can be effected stoichiometrically using lithium aluminium hydride. In another route, ethylamine can be synthesized via nucleophilic substitution of a haloethane (such as chloroethane or bromoethane) with ammonia, utilizing a strong base such as potassium hydroxide. This method affords significant amounts of byproducts, including diethylamine and triethylamine.[6]

CH3CH2Cl + NH3 + KOH → CH3CH2NH2 + KCl + H2O

Ethylamine is also produced naturally in the cosmos; it is a component of interstellar gases.[7]

Reactions

Like other simple aliphatic amines, ethylamine is a weak base: the pKa of [CH3CH2NH3]+ has been determined to be 10.8[8][9]

Ethylamine undergoes the reactions anticipated for a primary alkyl amine, such as acylation and protonation. Reaction with sulfuryl chloride followed by oxidation of the sulfonamide give diethyldiazene, EtN=NEt.[10] Ethylamine may be oxidized using a strong oxidizer such as potassium permanganate to form acetaldehyde.

Ethylamine like some other small primary amines is a good solvent for lithium metal, giving the ion [Li(amine)4]+ and the solvated electron. Such solutions are used for the reduction of unsaturated organic compounds, such as naphthalenes[11] and alkynes.

Applications

Ethylamine is a precursor to many herbicides including atrazine and simazine. It is found in rubber products as well.[4]

Ethylamine is used as a precursor chemical along with benzonitrile (as opposed to o-chlorobenzonitrile and methylamine in ketamine synthesis) in the clandestine synthesis of cyclidine dissociative anesthetic agents (the analogue of ketamine which is missing the 2-chloro group on the phenyl ring, and its N-ethyl analog) which are closely related to the well known anesthetic agent ketamine and the recreational drug phencyclidine and have been detected on the black market, being marketed for use as a recreational hallucinogen and tranquilizer. This produces a cyclidine with the same mechanism of action as ketamine (NMDA receptor antagonism) but with a much greater potency at the PCP binding site, a longer half-life, and significantly more prominent parasympathomimetic effects.[12]

References
  1. Merck Index, 12th Edition, 3808.
  2. "Ethylamine". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. NIOSH Pocket Guide to Chemical Hazards. "#0263". National Institute for Occupational Safety and Health (NIOSH).
  4. Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke, "Amines, Aliphatic" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.doi:10.1002/14356007.a02_001
  5. Ulrich Steinbrenner, Frank Funke, Ralf Böhling, Method and device for producing ethylamine and butylamine Archived 2012-09-12 at archive.today, United States Patent 7161039.
  6. Nucleophilic substitution, Chloroethane & Ammonia Archived 2008-05-28 at the Wayback Machine, St Peter's School
  7. NRAO, "Discoveries Suggest Icy Cosmic Start for Amino Acids and DNA Ingredients", Feb 28 2013
  8. Wilson and Gisvold's Textbook of Organic Medicinal and Pharmaceutical Chemistry, 9th Ed. (1991), (J. N. Delgado and W. A. Remers, Eds.) p.878, Philadelphia: Lippincott and 10.63.
  9. H. K. Hall, Jr. (1957). "Correlation of the Base Strengths of Amines". J. Am. Chem. Soc. 79 (20): 5441–5444. doi:10.1021/ja01577a030.
  10. "AZOETHANE". Organic Syntheses. 52: 11. 1972. doi:10.15227/orgsyn.052.0011.
  11. Kaiser, E. M.; Benkeser R. A. Δ9,10-Octalin Archived 2007-09-30 at the Wayback Machine, Organic Syntheses, Collected Volume 6, p.852 (1988)
  12. "World Health Organization Critical Review Report of Ketamine, 34th ECDD 2006/4.3" (PDF).
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