2-Butyne

2-Butyne (dimethylacetylene, crotonylene or but-2-yne) is an alkyne with chemical formula CH3C≡CCH3. Produced artificially, it is a colorless, volatile, pungent liquid at standard temperature and pressure.

2-Butyne[1][2]
Names
Preferred IUPAC name
But-2-yne
Other names
Dimethylacetylene
Crotonylene
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.007.239
UNII
Properties
C4H6
Molar mass 54.0904 g/mol
Density 0.691 g/mL
Melting point −32 °C (−26 °F; 241 K)
Boiling point 27 °C (81 °F; 300 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

2-Butyne is of interest to physical chemists because of its very low torsional barrier and the problem of determining that barrier using high-resolution infrared spectroscopy. Analysis of its spectrum[3] leads to a determination that the torsional barrier is only 6 cm−1(1.2x10−22 J). However, it has not been determined whether the equilibrium structure is eclipsed (D3h) or staggered (D3d). Symmetry analysis using the Molecular Symmetry Group[4] G36 shows that one would need to analyse its high resolution rotation-vibration Raman spectrum to determine its equilibrium structure.

2-Butyne (dimethylethin) forms with 5-decyne (dibutylethin), 4-octyne (dipropylethin) and 3-hexyne (diethylethin) a group of symmetric alkynes.

Synthesis

2-Butyne can be synthesized by the rearrangement of ethylacetylene in a solution of ethanolic potassium hydroxide.[5]

Applications

2-Butyne, along with propyne, is used to synthesize alkylated hydroquinones in the total synthesis of Vitamin E.[6]

gollark: That's the simplified form.
gollark: Oops, sorry, code error, it's (x - 2) * -1 / 1.8144e+5 * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) / 13440 * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * -1 / 2016 * (x - 2) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * 7 / 4320 * (x - 2) * (x - 3) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * -11 / 2880 * (x - 2) * (x - 3) * (x - 4) * (x - 6) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * 13 / 2880 * (x - 2) * (x - 3) * (x - 4) * (x - 5) * (x - 7) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * -17 / 4320 * (x - 2) * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 8) * (x - 9) * (x - 10) + (x - 1) * 19 / 10080 * (x - 2) * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 9) * (x - 10) + (x - 1) * -23 / 40320 * (x - 2) * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 10) + (x - 1) * 29 / 3.6288e+5 * (x - 2) * (x - 3) * (x - 4) * (x - 5) * (x - 6) * (x - 7) * (x - 8) * (x - 9).
gollark: This is such an elegant, clear and useful™ formula.
gollark: y = (x - 3) * -1 / 2.14708725e+8 * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) / 3.72736e+7 * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) * -1 / 1.3934592e+7 * (x - 3) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) / 1.01376e+7 * (x - 3) * (x - 5) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) * -5 / 3.5831808e+7 * (x - 3) * (x - 5) * (x - 7) * (x - 13) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) / 6.7584e+6 * (x - 3) * (x - 5) * (x - 7) * (x - 11) * (x - 17) * (x - 19) * (x - 23) * (x - 29) + (x - 2) * -1 / 1.24416e+7 * (x - 3) * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 19) * (x - 23) * (x - 29) + (x - 2) / 2.193408e+7 * (x - 3) * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 23) * (x - 29) + (x - 2) * -1 / 2.322432e+8 * (x - 3) * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 29) + (x - 2) / 7.685922816e+9 * (x - 3) * (x - 5) * (x - 7) * (x - 11) * (x - 13) * (x - 17) * (x - 19) * (x - 23)for instance.
gollark: > Factorials can be defined with an integral, so you could theoretically add x! to your y?My thing can EVEN make a formula for prime numbers! Specifically a small set of ones you supply beforehand!

See also

References
  1. 2-Butyne at Sigma-Aldrich
  2. NIST Chemistry WebBook page for 2-butyne
  3. di Lauro, C.; et al. (1997). "The rotation-torsion structure in the ν11/ν15 (Gs) methyl rocking fundamental band in dimethylacetylene". J. Mol. Spectrosc. 184 (1): 177–185. doi:10.1006/jmsp.1997.7321.
  4. Longuet-Higgins, H.C. (1963). "The symmetry groups of non-rigid molecules". Molecular Physics. 6 (5): 445–460. Bibcode:1963MolPh...6..445L. doi:10.1080/00268976300100501.
  5. Victor von Richter; Hans Meerwein (1916). Organic Chemistry: Chemistry of the aliphatic series Vol. I: Smith's 3rd American Ed. Philadelphia: P. Blakiston's Sons & Co. p. 89.
  6. Reppe, Walter; Kutepow, N; Magin, A (1969). "Cyclization of Acetylenic Compounds". Angewandte Chemie International Edition in English. 8 (10): 727–733. doi:10.1002/anie.196907271.


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