1-Butyne

{{chembox

| verifiedrevid = 445843216

| Name = 1-Butyne

| ImageFile = $\backslash ce\{H-C\#C\}\{-\}$

\ce{\overset{\displaystyle{H} \atop |}{\underset

\atop \displaystyle{H}}C}}{-} \ce{\overset{\displaystyle{H} \atop

{\underset{| \atop \displaystyle{H}}C}}

\ce{-H}

| ImageSize = 180px

| ImageName = Simplified skeletal formula

| ImageFile1 = But-1-yne-2D-skeletal.png

| ImageSize1 = 140px

| ImageName1 = Full displayed formula

| ImageFile2 = 1-Butyne-3D-vdW.png

| ImageSize2 = 160px

| ImageName2 = Space-filling model

| PIN = But-1-yne

| OtherNames = Ethylacetylene
Ethylethyne, UN 2452

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 7558

| PubChem = 7846

| InChI = 1/C4H6/c1-3-4-2/h1H,4H2,2H3

| InChIKey = KDKYADYSIPSCCQ-UHFFFAOYAI

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C4H6/c1-3-4-2/h1H,4H2,2H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = KDKYADYSIPSCCQ-UHFFFAOYSA-N

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 107-00-6

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = A6B47CPN6W

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 48087

| EC_number = 203-451-3

| UNNumber = 2452

| SMILES = C#CCC

}}

|Section2={{Chembox Properties

| Properties_ref =

| Formula = C₄H₆

| MolarMass = 54.091 g/mol

| Odor = Acetylenic{{cite web |title=Safety Data Sheet: Ethyl Acetylene |url=https://www.airgas.com/msds/001148.pdf |publisher=Airgas |access-date=2 April 2025 |date=19 August 2019}}

| Density = 0.6783 g cm⁻³

| MeltingPtC = −125.7

| MeltingPt_ref =

| BoilingPtC = 8.08

| BoilingPt_ref =

}}

|Section7={{Chembox Hazards

| GHSPictograms = {{GHS02}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|H220}}

| PPhrases = {{P-phrases|P210|377|381|403}}

| FlashPt = 7°C (45°F)Gangolli, S.. (2005). Dictionary of Substances and Their Effects (DOSE, 3rd Electronic Edition). Royal Society of Chemistry (RSC). [https://app.knovel.com/hotlink/toc/id:kpDSTEDOS3/dictionary-substances/dictionary-substances Retrieved from here]

}}

}}

1-Butyne is an organic compound with the formula {{chem2|CH3CH2C\tCH}}. It is a terminal alkyne. The compound is a common terminal alkyne substrate in diverse studies of catalysis. It is a colorless combustible gas.{{cite book |title= CRC Handbook of Chemistry and Physics, 89th Edition |last= Lide |first= David R. |year= 2008 |publisher= CRC Press |isbn= 978-0-8493-0488-0 |pages=3–84}} In 2017, {{convert|3.9 |e6lbs|long ton}} was produced in the USA.{{cite web |last1=EPA |first1=US |title=US EPA: Chemical Data Reporting: 1-Butyne |url=https://chemview.epa.gov/chemview/ |website=chemview.epa.gov |access-date=2 April 2025 |language=en}}

1-Butyne participates in reactions typical for terminal alkynes, such as alkyne metathesis,{{cite journal |doi=10.1021/ja0379868|title=Highly Active Trialkoxymolybdenum(VI) Alkylidyne Catalysts Synthesized by a Reductive Recycle Strategy|year=2004|last1=Zhang|first1=Wei|last2=Kraft|first2=Stefan|last3=Moore|first3=Jeffrey S.|journal=Journal of the American Chemical Society|volume=126|issue=1|pages=329–335|pmid=14709099}} hydrogenation, condensation with formaldehyde. Based on its heat of combustion, it is slightly more stable than its isomer 2-butyne.{{cite journal |doi=10.6028/jres.046.015|title=Heats of combustion, formation, and insomerization of ten C4 hydrocarbons|year=1951|last1=Prosen|first1=E.J.|last2=Maron|first2=F.W.|last3=Rossini|first3=F.D.|journal=Journal of Research of the National Bureau of Standards|volume=46|issue=2|page=106|doi-access=free}}

The combustion of 1-Butyne produces propargyl radicals, a pre-cursor to soot and polycyclic aromatic hydrocarbons, as the propargyl radicals can form basic aromatic rings, making butyne's fuel usage a concern for emissions.{{cite journal |last1=Lu |first1=Haitao |last2=Dong |first2=Shijun |last3=Liu |first3=Fuqiang |last4=Nagaraja |first4=Shashank S. |last5=Lindblade |first5=Nathan |last6=Turner |first6=Mattias A. |last7=Mathieu |first7=Olivier |last8=Petersen |first8=Eric L. |last9=Vilchez |first9=Jesús Caravaca |last10=Heufer |first10=Karl Alexander |last11=Xu |first11=Gang |last12=Sarathy |first12=S. Mani |last13=Curran |first13=Henry J. |title=A wide-range experimental and kinetic modeling study of the pyrolysis and oxidation of 1-butyne |journal=Proceedings of the Combustion Institute |date=1 January 2023 |url=https://www.sciencedirect.com/science/article/pii/S1540748922004357 |volume=39 |issue=1 |pages=355–364 |doi=10.1016/j.proci.2022.09.044 |access-date=2 April 2025}}

1-Butyne is in unsatutared C₄ petroleum cuts, and has to be separated out in industrial hydrorefining to make 1-butene, which is used to make low density polyethylene and polybutene. Distillation is impractical due to similar boiling points, so 1-butyne is removed by catalytic hydrogenation.{{cite journal |last1=García Colli |first1=G. |last2=Alves |first2=J. A. |last3=Martínez |first3=O. M. |last4=Barreto |first4=G. F. |title=Application of a catalytic membrane reactor to the selective hydrogenation of 1-Butyne |journal=Chemical Engineering and Processing - Process Intensification |date=1 August 2019 |volume=142 |pages=107518 |doi=10.1016/j.cep.2019.04.018}} Usually the catalyst is palladium, operated with liquid hydrocarbon and hydrogen gas at 20-60°C and pressures up to 10 bar.{{cite journal |last1=Alves |first1=J. A. |last2=Bressa |first2=S. P. |last3=Martínez |first3=O. M. |last4=Barreto |first4=G. F. |title=Kinetic study of the liquid-phase hydrogenation of 1-butyne over a commercial palladium/alumina catalyst |journal=Chemical Engineering Journal |date=15 January 2007 |volume=125 |issue=3 |pages=131–138 |doi=10.1016/j.cej.2006.08.006 |url=https://www.sciencedirect.com/science/article/pii/S1385894706003226|hdl=11336/54075 |hdl-access=free }}