Rearrangement in the homogeneous elimination kinetics of 3-chloro-2,2-dimethylpropan-1-ol in the gas phase
作者:Gabriel Chuchani、Rosa M. Dominguez
DOI:10.1002/(sici)1099-1395(199608)9:8<583::aid-poc818>3.0.co;2-z
日期:1996.8
3-Chloro-2,2-dimethylpropan-1-ol was pyrolysed in a static system at 410.0-459.1 degrees C and 62-179 Torr. The reaction, in a seasoned vessel and in the presence of the free radical suppressor propene, is homogeneous, unimolecular, and follows a first-order rate law, The rate coefficient follows the Arrhenius equation: log k(1) (s(-1)) = (13.14 +/- 0.15) - (218.8 +/- 2.1) kJ mol(-1) (2.303RT)(-1). The products are isobutene, formaldehyde and HCl gas. The exclusive intramolecular migration of the CH2OH group to the positively charged carbon atom, from the C-Cl bond polarisation, appears to proceed by way of an intimate ion-pair type of mechanism, The intermediate 3-methylbut-3-en-1-ol, under the reaction conditions, undergoes a six-centered decomposition characteristic of beta-hydroxyalkenes to produce isobutene, formaldehyde and HCl. The pyrolysis of the deuterated substrate, 3-chloro-2,2-dimethylpropan-1-[H-2]ol, serves to support the mechanistic consideration assumed above.