2-Butyne

Alkyne with four carbon atoms 403365671 at Sigma-AldrichNIST Chemistry WebBook page for 2-butyne 2-Butyne H3C-C#C-CH3 180px Structural formula 2-butyne-3D-balls-B.png 150px Ball-and-stick model bg-transparent But-2-yne DimethylacetyleneCrotonylene correct chemspider 9990 10419 correct EBI 119108 1/C4H6/c1-3-4-2/h1-2H3 XNMQEEKYCVKGBD-UHFFFAOYAO correct chemspider 1S/C4H6/c1-3-4-2/h1-2H3 correct chemspider XNMQEEKYCVKGBD-UHFFFAOYSA-N correct CAS 503-17-3 correct FDA LKE6D3018E CC#CC 4 6 0.691 g/mL -32 27 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 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 infrared spectrum di Lauro C. etal 1997 The rotation-torsion structure in the ν11/ν15 (Gs) methyl rocking fundamental band in dimethylacetylene J. Mol. Spectrosc. 184 1 177–185 10.1006/jmsp.1997.7321 leads to a determination that the torsional barrier is only 6 cm−1 (1.2-22 J or 72 J mol−1). However, it has not been determined whether the equilibrium structure is eclipsed (D3h) or staggered (D3d). Symmetry analysis using the Molecular Symmetry Group Longuet-Higgins H.C. 1963 The symmetry groups of non-rigid molecules Molecular Physics 6 5 445–460 10.1080/00268976300100501 1963MolPh...6..445L free P. R. Bunker 1964 The Rotation-Torsion Wavefunctions of Molecules that have two Identical Rotors Mol. Phys. 8 81 10.1080/00268976400100091 G36 shows that one would need to analyse its high resolution rotation-vibration Raman spectrum to determine its equilibrium structure. Pulsed-field-ionisation zero-kinetic-energy (PFI-ZEKE) photoelectron spectra of 2-butyne and its fully deuterated isotopomer have been recorded and analysed. Jacovella Ugo etal 2015 Internal rotation, spin–orbit coupling, and low-frequency vibrations in the ground state of CH3–CC–CH+3 and CD3–CC–CD+3 Mol. Phys. 113 2115 10.1080/00268976.2015.1005708 20.500.11850/182812 free 2-Butyne (dimethylethyne) forms with 5-decyne (dibutylethyne), 4-octyne (dipropylethyne) and 3-hexyne (diethylethyne) a group of symmetric alkynes. Synthesis 2-Butyne can be synthesized by the rearrangement reaction of ethylacetylene in a solution of ethanolic potassium hydroxide.Victor von Richter Hans Meerwein Organic Chemistry: Chemistry of the aliphatic series Vol. I: Smith's 3rd American Ed. 1916 P. Blakiston's Sons & Co. Philadelphia 89 https://books.google.com/books?id=UWlZAAAAYAAJ&q=dimethylacetylene+preparation&pg=PA89 Applications 2-Butyne, along with propyne, is used to synthesize alkylated hydroquinones in the total synthesis of Vitamin E.Reppe, Walter Kutepow, N Magin, A Cyclization of Acetylenic Compounds Angewandte Chemie International Edition in English 1969 8 10 727–733 10.1002/anie.196907271 See also Acetylenedicarboxylic acid 1-Butyne, a position isomer 1,4-Butynediol Hexamethylbenzene, a product of 2-butyne trimerization Hexafluoro-2-butyne References Category:Alkynes