Very low-pressure pyrolysis (VLPP) of 3,3-dimethylbut-1-yne (tert-butyl acetylene). The heat of formation and stabilization energy of the dimethylpropargyl radical

✍ Scribed by Keith D. King

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 468 KB
• Volume: 9
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550090606

✦ Synopsis

The unimolecular decomposition of 3,3-dimethylbut-l-yne has been investigated over the temperature range of 933"-1182"K using the technique of very low-pressure pyrolysis (VLPP). The primary process is C-C bond fission yielding the resonance stabilized dimethylpropargyl radical. Application of RRKM theory shows that the experimental unimolecular rate constants are consistent with the high-pressure Arrhenius parameters given by log (klsec-l) = (15.8 f 0.3) -(70.8 f 1.5)/8 where 8 = 2.303RT kcal/mol. The activation energy leads to DH0[(CH&C(CCH)-CH3] = 70.7 f 1.5, AHP((CH&$CCHg) = 61.5 f 2.0, and DHO[(CH&C(CCH)-H] = 81.0 f 2.3, all in kcal/mol at 298°K. The stabilization energy of the dimethylpropargyl radical has been found to he 11.0 f 2.5 kcal/mol.