13275-39-3Relevant academic research and scientific papers
Synthesis of deuterium labeled isobutane: Isobutane-2-d1, isobutane-1-d9 and isobutane-d10
Sassi,Coeppert,Sommer,Esteves,Mota
, p. 1023 - 1030 (2007/10/03)
2-Methylpropane-2-d1 (isobutane-2-d1), 2-(methyl-d3)-propane-1,1,1,3,3,3-d6 (nonadeuterated isobutane) and 2-methylpropane-d10 (perdeuterated isobutane) were synthesized by using a combination of classical organic chemistry and recently developed H/D exchange processes on solid acids. Isobutane-2-d1 was synthesized from t-butyl chloride by Grignard synthesis with an overall yield of 27.0% (chemical purity: 99.9% and isotopic purity: 96.0%). Isobutane-1-d9 was prepared by H/D exchange of 2-methylpropane (isobutane) with a D2O exchanged zeolite. The deuteriated product was obtained with an overall yield of 80.0% (chemical purity: 99.9% and isotopic purity: 98.7%). Perdeuteriated isobutane was prepared by reacting isobutane-2-d1 with 98.0% deuteriated sulfuric acid and was obtained in a total yield of 98.0% (chemical purity: 99.8% and isotopic purity: 97.9%).
Hyperconjugation: Equilibrium Secondary Isotope Effect on the Stability of the tert-Butyl Cation. Kinetics of Thermoneutral Hydride Transfer
Meot-Ner, Michael (Mautner)
, p. 7947 - 7950 (2007/10/02)
The thermochemistry of the hydride transfer equilibrium (CD3)3C(1+) + (CH3)3CH ->/0 = -0.57 +/- 0.02 kcal/mol; ΔS0 = -0.57 +/- 0.08 cal/(mol.K); ΔG0298 = -0.40 +/- 0.07 kcal.mol; and K298 = 1.97 +/- 0.20.The direction of the observed isotope effect is consistent with C-H bond weakening in the ion due to hyperconjugation.The kinetics of the reaction show a slow rate and a large negative temperature coefficient, with k300 = 0.36 and k600 = 0.00625 x 1E-10 cm3 s-1, i.e., reaction efficiencies of about 0.03 to 0.0005.The observed negative temperature coefficient, k = AT-5.8, is larger than those observed for more exothermic hydride transfer reactions.The approach to collison rate is abrupt.
