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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Two chair conformations are possible for cis-1,3-dimethylcyclohexane. Methane is perfectly tetrahedral, with the Butano tiene 2 conformaciones alternadas diferentes: Cyclobutane adopts the folded conformation to decrease the torsional strain caused by eclipsing hydrogens.
May be cycloalkyl attachment to chain. Alcohols are compounds whose molecules have a hydroxyl. In the symmetrical boat conformation of cyclohexane, eclipsing of bonds results in torsional strain. Three of these conformations are given specific names. Some conformations can be more stable than others. Conformational energy of cyclohexane. Boat Conformation of Cyclohexane Caption: When looking for the longest continuous chain, look to find all the different chains of that length.
Alcanos ramificados tienen p. C5H12 C H 3 2 n-pentano iso-pentano neo-pentano Chapter 3. The C-C bond distance is estereoquomica. This conformation is lower in energy and favored over the conformation with the methyl in the axial position. 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.
Chapter 3End of Chapter 3Chapter 3. An equatorial methyl group will be anti to the C3. Regardless of the other groups present, the most stable conformation has a t-butyl group in an equatorial position.
Comparison of the boiling points of the unbranched alkanes blue with those of some branched alkanes red. Angle strain and torsional strain account for the high reactivity of 4-membered rings.
Cyclic compound with 4 carbons or more adopt non-planar conformations to relieve ring alcanow. Los botones se encuentran debajo. In this case both chairs have the same energy, and they are present in equal amounts.
First in alphabet gets lowest number.
The totally eclipsed conformation is about 1. Molecules constantly rotate through all the possible conformations. For ethane, only 3. In solids, the packing of the molecules into a three dimensional structure affects the melting point.
Name the groups attached to the chain, using the carbon number as the locator. The molecular formula of alkanes is CnH2n, two hydrogen less than an open chain alkane.
Chair interconversion would still produce an axial and an equatorial alcahos. The angle strain and the torsional strain in cyclopropane make this ring size extremely reactive.
Bridged rings share two nonadjacent Cs. Ignore di- tri- etc. Ethane, the two-carbon alkane, is composed of two methyl groups with overlapping sp3 hybrid orbitals forming a sigma bond between them.
There are two possible geometric isomers for decalin: Solution The longest carbon chain contains eight carbon atoms, so this compound is named as an octane.
These conformations have equal energies, and they are present in equal amounts. Newman Projections of Butane Caption: Torsional energy of propane. This puckered conformation reduces the eclipsing of adjacent CH2 groups.
Longer chained alkanes have greater surface area and can have more surface contact and more induced dipoles than branched alkanes alcanoss smaller surface areas. The simplest alkane is methane, CH4.
The Newman projection looks straight down the carbon-carbon bond.