Os alcanos son hidrocarburos, é dicir que teñen só átomos de carbono e .. difiren en enerxía: a conformación alternada é 12,6 kJ/mol menor en enerxía (por . Presentación del tema: “Estructura y Estereoquímica de Alcanos”— . Conformaciones son diferentes arreglos de los átomos producidos al rotar el enlace σ. Análisis conformacional del etano Análisis conformacional del butano Mecánica molecular aplicada a los alcanos y los cicloalcanos

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The C-C bond distance is 1. As they are numbered here, the odd-numbered carbons have their upward bonds axial and their downward bonds equatorial.

Cyclohexane can adopt four non-planar conformations: Cyclobutane adopts the folded conformation to decrease the torsional strain caused by eclipsing hydrogens. Sobre el proyecto SlidePlayer Condiciones de uso. Three of these conformations are given specific names.

La eclipsada es 3. Same Length Chains Caption: Structures of some conformacuones. In the Newman projection it is easier to see the steric interaction between the methyl substituent and the hydrogens and carbons of the ring. The molecular formula of alkanes is CnH2n, two hydrogen less than an open chain alkane.

Chair Conformations of alcanks Caption: To convert between these two conformations, the molecule must pass through the unstable half-chair conformation. Often, the longest chain with the most substituents is not obvious. Comparison of the boiling points of the unbranched alkanes blue with those of some branched alkanes red.


Estructura y Estereoquímica de Alcanos

Conformations of Cyclopentane Caption: Conformational Analysis of Butane Caption: The most stable conformation is the chair because it has all the C-H bonds staggered. Alkanes with an even number of carbons pack better than those with an odd number of carbons.

The axial bonds are directed vertically, parallel to the axis of the ring. There is steric hindrance between these hydrogens so the molecule twists a little producing the twist boat conformation which is 1. The eclipsed conformation is about 3. Angle strain and torsional strain account for the high reactivity of 4-membered rings.

Torsional energy of propane. Interconversion between chair conformations require that cyclohexane go through its higher energy conformations. All the carbon-carbon bonds are eclipsed, generating torsional strain that contributes to the total ring strain.


Ethane has two sp3 carbons. Conformational Energy Diagram of Cyclohexane Caption: The anti conformation is lowest in energy, and the totally eclipsed conformation is highest in energy.

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Solution The longest carbon chain contains eight carbon atoms, so this compound is named as an octane. Alcanos con par de C tienen p. The chair conformation of cyclohexane has one methylene group puckered upward and another puckered downward.

Análisis conformacional by Química Orgánica on Prezi

Los botones se encuentran debajo. Looking down the C1-C2 bond of the equatorial conformation, we find that the methyl group is anti comformaciones C3. Any carbon with four sigma bonds has an sp3 hybridization. Methane is perfectly tetrahedral, with the Totally Eclipsed Conformation of Butane Caption: The Newman projection looks straight down the carbon-carbon bond. To relieve ring strain, cyclopentane adopts the envelope conformation. This kind of interference between two bulky groups is called steric strain or steric hindrance.

Axial hydrogens are pointed straight up or down, parallel to the axis of the ring. The different arrangement formed by rotations about a single bond are called conformations, and a specific is called conformer.