Search results
Results from the WOW.Com Content Network
The staggered conformation is more stable by 12.5 kJ/mol than the eclipsed conformation, which is the energy maximum for ethane. In the eclipsed conformation the torsional angle is minimised. staggered conformation left, eclipsed conformation right in Newman projection
It was found that the most stable conformations had lower energies based on values of energy due to bond distances and bond angles. [ 6 ] In many cases, isomers of alkanes with branched chains have lower boiling points than those that are unbranched, which has been shown through experimentation with isomers of C 8 H 18 .
Ethane (US: / ˈ ɛ θ eɪ n / ETH-ayn, UK: / ˈ iː-/ EE-) is a naturally occurring organic chemical compound with chemical formula C 2 H 6. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum ...
B is highest & A lowest in energy. A is thus the most stable conformation. Valleys are local energy minima. A can thus be classified as a rotamer (a class of conformers). Peaks are not rotamers, & are caused by repulsive forces of the hydrogens. Source for conformation names & rotamer classification:
Staggered conformation image right in Newman projection Eclipsed conformation. In organic chemistry, a staggered conformation is a chemical conformation of an ethane-like moiety abcX–Ydef in which the substituents a, b, and c are at the maximum distance from d, e, and f; this requires the torsion angles to be 60°. [1]
The gauche effect is very sensitive to solvent effects, due to the large difference in polarity between the two conformers.For example, 2,3-dinitro-2,3-dimethylbutane, which in the solid state exists only in the gauche conformation, prefers the gauche conformer in benzene solution by a ratio of 79:21, but in carbon tetrachloride, it prefers the anti conformer by a ratio of 58:42. [9]
The anti conformation is more stable by 0.9 kcal mol −1. [1] We would expect that butane is roughly 82% anti and 18% gauche at room temperature. However, there are two possible gauche conformations and only one anti conformation. Therefore, entropy makes a contribution of 0.4 kcal in favor of the gauche conformation. [2]
Phase behavior Triple point: 91 K (−182 °C), 1.1 Pa Critical point: 305.3 K (32.2 °C), 4.9 MPa Std enthalpy change of fusion, Δ fus H o: 9.76 kJ/mol at −182 °C