Stereochemistry of Alkanes
Experiment #2: Stereochemistry of Alkenes and Molecular Modeling
By: Nouhad Mokdad
Section: 53
TA’s: Sheida and Ryan Mills
Lab Partner: David Wilson
Date of Experiment: October 7th, 2008
Purpose:
The purpose is to study the difference between the stereochemistry of the two isomers, maleic and fumaric acid. The first part of the experiment called for the conversion of maleic acid into fumaric acid with the addition of a proton using the acid-catalyzed isomerisation, vacuum filtration, and reflux processes. The second part of the experiment was intended for using the molecular modelling kits as a way to visualize the differences between such isomers.
Discussion:
Organic compounds and their three-dimensional shapes can be represented through diagrams. Two particular methods of illustrations are the sawhorse representation and the Newman projection. An example of both these methods is seen in figure 1. (1) | | | Sawhorse projection | Newman projectionFig. 1 |
The sawhorse representation examines a carbon-carbon bond from a certain angle, so that one is able to visualize the molecule as a whole. The bonds in the plane of the main chain are demonstrated by solid lines, bonds away from the viewer are represented by hatched lines, and bonds coming straight towards the viewer are drawn as solid wedges. The Newman projection views the carbon-carbon bond from front to back; the front carbon being represented by a dot and the back carbon represented by a circle. The three bonds in the front carbon are arranged 120° from each other while the same applies to the three bonds in the back carbon. The fourth bond is positioned in the middle of both the front and back carbons and is therefore not visible. The carbon-carbon bonds can be positioned in either the staggered or eclipsed formation (see Fig. 2 ). Staggered formation occurs when the substituents off of the front carbon are aligned with the substituent off of the back carbon. This is less
By: Nouhad Mokdad
Section: 53
TA’s: Sheida and Ryan Mills
Lab Partner: David Wilson
Date of Experiment: October 7th, 2008
Purpose:
The purpose is to study the difference between the stereochemistry of the two isomers, maleic and fumaric acid. The first part of the experiment called for the conversion of maleic acid into fumaric acid with the addition of a proton using the acid-catalyzed isomerisation, vacuum filtration, and reflux processes. The second part of the experiment was intended for using the molecular modelling kits as a way to visualize the differences between such isomers.
Discussion:
Organic compounds and their three-dimensional shapes can be represented through diagrams. Two particular methods of illustrations are the sawhorse representation and the Newman projection. An example of both these methods is seen in figure 1. (1) | | | Sawhorse projection | Newman projectionFig. 1 |
The sawhorse representation examines a carbon-carbon bond from a certain angle, so that one is able to visualize the molecule as a whole. The bonds in the plane of the main chain are demonstrated by solid lines, bonds away from the viewer are represented by hatched lines, and bonds coming straight towards the viewer are drawn as solid wedges. The Newman projection views the carbon-carbon bond from front to back; the front carbon being represented by a dot and the back carbon represented by a circle. The three bonds in the front carbon are arranged 120° from each other while the same applies to the three bonds in the back carbon. The fourth bond is positioned in the middle of both the front and back carbons and is therefore not visible. The carbon-carbon bonds can be positioned in either the staggered or eclipsed formation (see Fig. 2 ). Staggered formation occurs when the substituents off of the front carbon are aligned with the substituent off of the back carbon. This is less
References: 1) http://en.wikipedia.org/wiki/Newman_projection; October 20th, 2008 2) http://content.answers.com/main/content/wp/en-commons/thumb/b/b8/200px-Newman_projection_ethane.png; October 20th, 2008 5) http://msds.chem.ox.ac.uk/; October 20th, 2008 6) http://en.wikipedia.org/wiki/Maleic_anhydride; October 20th, 2008 7) http://en.wikipedia.org/wiki/Fumaric_acid; October 20th, 2008 8) http://en.wikipedia.org/wiki/Maleic_acid; October 20th, 2008 9) http://en.wikipedia.org/wiki/Hydrochloric_acid; October 20th, 2008 10) http://en.wikipedia.org/wiki/Water; October 20th, 2008