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

Author: Faedal Gumi
Country: Saint Kitts and Nevis
Language: English (Spanish)
Genre: Health and Food
Published (Last): 1 March 2011
Pages: 350
PDF File Size: 6.57 Mb
ePub File Size: 15.41 Mb
ISBN: 480-5-66186-723-8
Downloads: 74876
Price: Free* [*Free Regsitration Required]
Uploader: Kazraramar

This puckered conformation reduces the eclipsing of adjacent CH2 groups. Propane is shown here as a perspective drawing and as a Newman projection looking down one of the carbon-carbon bonds. Some common alkyl groups and their names.

The angle compression for butane is The six-membered rings in cis- and trans-decalin assume chair conformations. Conformations of Ethane Caption: The different arrangement formed by rotations about a single bond are called conformations, and a specific is called conformer.

Angle strain and torsional strain account for the high reactivity of 4-membered rings.

conformaciones de butano

The methyl group is axial in one conformation, and equatorial in the other. Alcohols are compounds whose molecules have a hydroxyl. The more stable conformation has both methyl groups cinformaciones equatorial positions. The Newman Projection of Propane Caption: The molecular conformzciones of alkanes is CnH2n, two hydrogen less than an open chain alkane.

Conformations of Cyclohexane Caption: Ambas conformaciones tienen un metil axial y otro ecuatorial. Methane is perfectly tetrahedral, with the Torsional strain in cyclopropane.

confformaciones When molecules can pack in neat order avoiding empty pockets the melting point will be higher than when the packing is not ordered. The anti conformation is lowest in energy, and the totally eclipsed conformation is highest in energy. Three of these conformations are given specific names.



Either of the chair conformations of trans-1,3-dimethylcyclohexane has one methyl group in an confoormaciones position and one in an equatorial position. In the symmetrical boat conformation of cyclohexane, eclipsing of bonds results in torsional strain.

Conformations of Cyclobutane Caption: La eclipsada es 3. To use this website, you must agree to our Privacy Policyincluding cookie policy. The C-C bond distance is 1. Angle Strain in Cyclopropane Caption: The simplest alkane is methane, CH4.

An error occurred.

The axial substituent interferes with the axial hydrogens on C3 and C5. To make this website work, we log user data and share it with processors.

Any carbon with four sigma bonds has an sp3 hybridization. Pure conformers cannot be isolated in most cases, because the molecules are constantly rotating through all the possible conformations.

Structures of some cycloalkanes. Butano tiene 2 conformaciones alternadas diferentes: Cyclobutane adopts the folded conformation to decrease the torsional strain caused by eclipsing hydrogens. Chair Conformations of cis-1,3-Dimethylcyclohexane Caption: Groups like tert-butyl are so bulky that it will force the chair conformation where it is in the equatorial position, regardless of other groups present.

Ethane, the two-carbon alkane, is composed of two methyl groups with overlapping sp3 hybrid orbitals forming a sigma bond between them. Two chair conformations are possible for cis-1,3-dimethylcyclohexane. Torsional energy of propane. Los substituyentes axiales alcahos con los H axiales del C 3 y C 5. Longer chained alkanes have greater surface conformacinoes and can have more surface contact and more induced dipoles than branched alkanes with smaller surface areas.


Cyclic compound with 4 carbons or more adopt non-planar conformations to relieve ring strain. Conformational Analysis of Ethane Caption: The most stable alcannos is the chair because it has alcanoa the C-H bonds staggered. Cyclohexane can adopt four non-planar conformations: Conformational Energy Diagram of Cyclohexane Caption: Since the methyl group occupies more space than a hydrogen, the torsional strain will be 0. The staggered conformations are lower in energy than the eclipsed conformation because the staggering allows the electron clouds of the C-H bonds to be as far apart as possible.

The high reactivity of cyclopropanes is due to the non-linear overlap of the sp3 orbitals. Often, the longest chain with the most substituents is not obvious. Newman Projections qlcanos Butane Caption: Alkanes with an even number of carbons pack better than those with an odd number of carbons. The Newman projection is the best way to judge the stability of the different conformations of a molecule.