Download Wade03 estructura y estereoquimica de alcanos . leccin 5. alcanos y cicloalcanos – orgnica 2 leccin 5. Documents. estereoquímica introducción los isómeros estructurales se definen como isómeros, todos aquellos compuestos químicos que poseen igual fórmula global, . Estereoquímica es el término aplicado a los aspectos tridimensionales de la estructura CAPÍTULO TRES Conformaciones de alcanos y cicloalcanos.
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Straight chain actually is zigzag. First in alphabet gets lowest number. Alcanos con par de C tienen p.
Because of their smaller surface areas, branched alkanes have lower boiling points than unbranched alkanes. Either of the chair conformations of trans-1,3-dimethylcyclohexane has one methyl group in an axial position and one in an equatorial position. If two substituents are equidistant, look for the next closest group.
Same Length Chains Caption: Methane is perfectly tetrahedral, with the The six-membered rings in cis- and trans-decalin assume chair conformations. Chapter 3CyclohexaneCombustion data shows its unstrained.
All the C-H bonds are staggered in the chair conformation. This conformation is lower in energy and favored over estereqouimica conformation with the methyl in the axial position. Name the branch off the branch using a locator number. Sobre el proyecto SlidePlayer Condiciones de uso.
Substituents on a carbon chain are called alkyl groups. The Newman projection looks straight down the carbon-carbon bond. Chair interconversion would still produce an axial and an equatorial methyl.
Torsional strain in cyclopropane. Groups like tert-butyl are so bulky that it will force the chair estereoquijica where it is in the equatorial position, regardless of other groups present. Alcohols are compounds whose molecules have a hydroxyl. The simplest alkane is methane, CH4.
Nomenclature of D Groups Caption: Some common alkyl groups and their names. Their physical properties resemble those of alkanes. The Newman projection is the best way to judge the stability of the different conformations of a molecule.
Interconversion between chair conformations require that cyclohexane go through its higher energy conformations. Comparison of the boiling points of the unbranched alkanes blue with those of some branched alkanes red.
Wade03 estructura y estereoquimica de alcanos
Esta interferencia es llamada interacciones 1,3-diaxial. Alkanes ckcloalcanos an even number of carbons pack better than those with an odd number of carbons. Conformations of Cyclohexane Caption: Torsional energy of propane. Three of these conformations are given specific names. The Newman Projection of Propane Caption: Puckered conformer reduces torsional strain. Pure conformers cannot be isolated in most cases, because the molecules are constantly rotating through all the possible conformations.
El Cis-1,3-dimetilciclohexano puede tener ambos grupos axiales o ecuatoriales. Propane is shown here as a perspective drawing and as a Newman projection looking down one of the carbon-carbon bonds. The melting point curve for n-alkanes with even numbers of carbon atoms is slightly higher than that for alkanes with odd numbers of carbons. Chair Conformations of trans-1,3-Dimethylcyclohexane Caption: Alkyl substituents on cyclohexane rings will tend to be equatorial to avoid 1,3-diaxial interactions.
Estructura y Estereoquímica de Alcanos – ppt video online descargar
Alcanos ramificados tienen p. Los botones se encuentran debajo. Some conformations can be more stable than others. The other cicloalcanod conformations are lower in energy than the totally eclipsed conformation but are still more unstable than the staggered conformations. Cyclohexanes with tertiary-butyl substituents show that an axial t-butyl group is eetereoquimica hindered. Much like ethane the staggered conformations of propane is lower in energy than the eclipsed conformations.
Butano tiene 2 conformaciones alternadas diferentes: Angle strain in cyclopropane.
Axial hydrogens are pointed straight up or down, parallel to the axis of the ring. Conformational Analysis of Butane Caption: Conformational Energy Diagram of Cyclohexane Caption: