View alcanos_ from CIENCIAS D at Marista University of Guadalajara. Estructura y conformaciones de los alcanos Conformacin Eclipsada. Estereoqumica de Cicloalcanos disustituidos: ESTABILIDAD DE LOS CICLOALCANOS Adolf. Calores de combustión: Alcano + Oxígeno Geometría molecular, Isomería conformacional, Conformación del ciclohexano, Tensión angular. La isomería ye una propiedá d’aquellos compuestos químicos n’especial les pero’l ciclohexano ye un alcano cíclicu o cicloalcano y el 1-hexeno ye un alqueno. . Los isómeros conformacionales xeneralmente nun son xebrables o.
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Isomería – Wikipedia
These conformations have equal energies, and they are present in equal amounts. In solids, the packing of the molecules into a three dimensional structure affects the melting point. Conformational energy of cyclohexane.
The Newman Projection of Propane Caption: The angle strain and the torsional strain in cyclopropane make this ring size extremely reactive.
Conformational Analysis of Propane Caption: In this case both chairs have the same energy, and they are present in equal amounts.
This interference is called a 1,3-diaxial interaction.
Conformations of Cyclopropane Caption: The more stable conformation conformacoinal both methyl groups in equatorial positions. The following figure shows the severe steric interactions in a chair conformation with a t-butyl group axial.
Some groups are so bulky that they are extremely hindered in ismoeria positions. Ambas conformaciones tienen un metil axial y otro ecuatorial. The different arrangement formed by rotations about a single bond are called conformations, and a specific is called conformer. The totally eclipsed conformation is about 1.
Conformations with Extremely Bulky Groups Caption: The anti conformation is lowest in energy, and the totally eclipsed conformation is highest in energy. All the C-H bonds are staggered in the chair conformation.
Estructura y Estereoquímica de Alcanos – ppt video online descargar
As they are numbered here, the odd-numbered carbons have their upward bonds axial and their downward bonds equatorial. Their physical properties resemble those of alkanes.
When molecules can pack in neat order avoiding empty pockets the melting point will be higher than when the packing is not ordered. Comparison of the boiling points of the unbranched alkanes blue with those of some branched alkanes red. Chair Conformation of Cyclohexane Caption: Ethane, the two-carbon alkane, conformaciinal composed of two methyl groups with overlapping sp3 hybrid orbitals forming a sigma bond between them.
The most stable conformation is the chair because it has all the C-H bonds staggered. Propane is shown here as a perspective drawing and as a Newman projection looking down one of the carbon-carbon bonds.
Three of these conformations are given specific names. The Newman projection is the best way to judge the stability of the different conformations of a molecule. Sobre el proyecto SlidePlayer Condiciones de uso.
Estructura y Estereoquímica de Alcanos
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. Conformations of Cyclohexane Caption: All the carbon-carbon bonds are eclipsed, generating torsional strain that contributes to the total ring strain.
Chair Conformations of trans-1,3-Dimethylcyclohexane Caption: To relieve ring strain, cyclopentane adopts the envelope conformation. Angle strain and torsional strain account for the high reactivity of 4-membered rings.
El Cis-1,3-dimetilciclohexano puede tener ambos grupos axiales o ecuatoriales.
Chair interconversion would still produce an axial and an equatorial methyl. The unfavorable conformation has both methyl groups in axial positions, with a 1,3-diaxial interaction between them. Melting Points of Alkanes Caption: This conformation is lower in energy and favored over the conformation with isomegia methyl in the axial position.
There are two possible geometric isomers for decalin: The eclipsed conformation is about 3. Nomenclature of Alkyl Groups Caption: The ring strain of a planar cyclobutane results from two factors: Los substituyentes axiales interfieren con los H axiales del C 3 y C 5.
Often, the longest chain with the most substituents is not obvious. Structures of some cycloalkanes. An equatorial methyl group will be anti to the C3. The simplest alkane is methane, CH4.