1-Butene

Athanor · official

C₄H₈ · 56.11 g/mol

IUPAC name: but-1-ene

Also called alpha-butylene

Reagents Functional groups

Open in Athanor

Drawn from its SMILES with RDKit

DangerExtremely flammable gas

Names and identifiers

IUPAC name: but-1-ene
Synonyms: alpha-butylene, But-1-ene, Ethylethylene
+ 32 more
1-Butylene, alpha-Butylene, Butene-1, alpha-Butene, LY001N554L, DTXSID1026746, CHEBI:48362, RefChem:6715, DTXCID606746, 203-449-2, BUTENE, 1-Butene-1-13C, .alpha.-Butene, .alpha.-Butylene, 1-C4H8, Isotactic poly(1-butene), MFCD00009383, Butene, 1-, CCRIS 8970, HSDB 179, But-1-ene (10% in Hexanes), EINECS 203-449-2, UNII-LY001N554L, Actipol E6, 1-BUTENE [HSDB], EC 203-449-2, SCHEMBL1328, SCHEMBL2650, SCHEMBL6239, 1-BUTENE [MI], 1-Butene, >=99%, SCHEMBL10862
Molecular formula: C₄H₈
Empirical formula: CH₂
Molecular weight: 56.11 g/mol
Exact mass: 56.06260
CAS number: 106-98-9
PubChem CID: 7844
Canonical SMILES: CCC=C
Isomeric SMILES: CCC=C
InChI: InChI=1S/C4H8/c1-3-4-2/h3H,1,4H2,2H3
InChIKey: VXNZUUAINFGPBY-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: 1-butene is a colorless gas. (NTP, 1992)[1]
3 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
–shown 1-butene is a colorless gas. (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– Gas Vapor; Liquid; Liquid; Gas Vapor; Other Solid [2] EPA Chemical Data Reporting (CDR)
– Gas Vapor; Liquid [2] EPA Chemical Data Reporting (CDR)
Odor: Slightly aromatic odor[3]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
–shown Slightly aromatic odor [3] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V2: 727
– Gassy, slightly aromatic odor [3] Hazardous Substances Data Bank (HSDB)cites Carreon T, Herrick RL; Aliphatic Hydrocarbons. Patty's Toxicology. 6th ed. (1999-2017). New York, NY: John Wiley & Sons, Inc. On-line Posting Date: 17 Aug 2012.
Melting point: -185.3 °C[4]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
−185.3 °C -301.5 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−185.3 °Cshown -185.3 °C [4] PAC Chemical Database, U.S. Department of Energy
Boiling point: -6.3 °C @760 [mmHg][4]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
−6 °C 21 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−6.3 °Cshown -6.3 °C @760 [mm Hg] [4] PAC Chemical Database, U.S. Department of Energy
Density: 0.6255 at -6.7 °C (19.9 °F) (NTP, 1992) - Less dense than water[1]
2 values
Sources disagree; from CAMEO Chemicals, the most authoritative.
Value As written Source
–shown 0.6255 at 19.9 °F (NTP, 1992) - Less dense than water [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– 0.557 @25 °C [4] PAC Chemical Database, U.S. Department of Energy
2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Solubility in water: In water, 221 mg/L at 25 °C[3]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Insoluble (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown In water, 221 mg/L at 25 °C [3] Hazardous Substances Data Bank (HSDB)cites McAuliffe C; J Phys Chem 70: 1267-75 (1966)
log P: log Kow = 2.40[3]
Vapor pressure: Vapor pressure: 3480 mmHg at 21 °C[3]
4 values
2 of 3 sources agree on it (most common value).
Value As written Source
3480 mmHg 3480 mmHg at 70 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
3480 mmHgshown Vapor pressure: 3480 mm Hg at 21 °C [3] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V2: 727
2253 mmHg 2.253X10+3 mm Hg at 25 °C [3] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
2253 mmHg 2253 [mm Hg] @25 °C [4] PAC Chemical Database, U.S. Department of Energy
Flash point: -79 °C (-110 °F, NTP 1992)[1]
Autoignition temperature: 385 °C (725 °F)[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
384 °C 723 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
385 °Cshown 725 °F (385 °C) [3] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-22

Value	As written	Source
–shown	1-butene is a colorless gas. (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	Gas Vapor; Liquid; Liquid; Gas Vapor; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	Gas Vapor; Liquid	[2] EPA Chemical Data Reporting (CDR)

Value	As written	Source
–shown	Slightly aromatic odor	[3] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V2: 727
–	Gassy, slightly aromatic odor	[3] Hazardous Substances Data Bank (HSDB)cites Carreon T, Herrick RL; Aliphatic Hydrocarbons. Patty's Toxicology. 6th ed. (1999-2017). New York, NY: John Wiley & Sons, Inc. On-line Posting Date: 17 Aug 2012.

Value	As written	Source
−185.3 °C	-301.5 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−185.3 °Cshown	-185.3 °C	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
−6 °C	21 °F at 760 mmHg (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−6.3 °Cshown	-6.3 °C @760 [mm Hg]	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–shown	0.6255 at 19.9 °F (NTP, 1992) - Less dense than water	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	0.557 @25 °C	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	Insoluble (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown	In water, 221 mg/L at 25 °C	[3] Hazardous Substances Data Bank (HSDB)cites McAuliffe C; J Phys Chem 70: 1267-75 (1966)

Value	As written	Source
3480 mmHg	3480 mmHg at 70 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
3480 mmHgshown	Vapor pressure: 3480 mm Hg at 21 °C	[3] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V2: 727
2253 mmHg	2.253X10+3 mm Hg at 25 °C	[3] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
2253 mmHg	2253 [mm Hg] @25 °C	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
384 °C	723 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
385 °Cshown	725 °F (385 °C)	[3] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-22

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 4
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.5
H-bond donors: 0
H-bond acceptors: 0
Rotatable bonds: 1
TPSA (Å²): 0
Formal charge: 0
XLogP3: 2.4 PubChem
Complexity: 14 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C85.63%
H14.37%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 1.58 Crippen (Wildman and Crippen 1999)
log S (water solubility): -1.12 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.72 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 56.11
log P ≤ 5 (Crippen): 1.58
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 0

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [5].

Flammable
Compressed gas

NFPA 704[3]

H220Extremely flammable gas

Precautionary statements: P203, P210, P222, P280, P377, P381, P403

View all classifications (6)

[5] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH220
[6] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.1% (2 of 1383) of reports.
[6] European Chemicals Agency (ECHA) · 1,383 reports · DangerH220, H280
[6] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.3% (1 of 399) of reports.
[6] European Chemicals Agency (ECHA) · 399 reports · DangerH220, H280
[3] Hazardous Substances Data Bank (HSDB) · DangerH220, H280

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Caution: Exposure of skin to compressed gases may result in freezing of the skin. Treatment for frostbite may be necessary.[1]

Storage

Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases[3]

Incompatibilities

Mixtures with aluminum tetrahydroborate explode after an induction period.[3]
The tetrahydroborate reacts with alkenes and, in presence of oxygen, combustion is initiated even in absence of moisture. Butene explodes after an induction period, while butadiene explodes immediately.[3]

Safety data sheets on the supplier’s page: Mcule, AA BLOCKS, RR Scientific.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[4]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[5]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[6]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[7]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[8]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[9]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[10]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[11]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.