Petroleum ether is composed of a mixture of larger alkanes more than six carbonswhereas hexane is only composed of six-carbon alkanes. Review diastereotopic hydrogens, starting near the bottom of page This alternative constitutes a powerful synthesis of six-membered ring heterocycles.
Since the petroleum ether is composed of larger alkanes, there are more intermolecular forces than are present in hexane; this consequence means that the environment of petroleum ether is slightly more soluble for polar molecules. As such, the Diels—Alder reaction is governed by orbital symmetry considerations: Show the correlations between all coupled hydrogens in the COSY using dotted lines to connect the peaks.
Both the anthracene and maleic anhydride dissolved immediately in xylene to give a slightly yellow solution. A series of reactions then follow to transform the functionality into a desirable group.
A peak at cm-1 represented the carbon-oxygen functional group. A peak at 3. Mechanism[ edit ] The reaction is an example of a concerted pericyclic reaction. It is vital to keep stirring the reaction and not stop until it liquefies and then solidifies. You will perform the following analyses on your product: The first issue could be solved by devising a method of transferring the filtered and dried crystal product from the filtration funnel or beaker in a manner that conserves the product.
The data should be presented as an ordered numbered list. The non-polar product should experience greater solubility in petroleum ether than in hexane due to the greater Van der Waals forces in the petroleum ether. Since all three rings of anthracene can not simultaneously have benzenoid character Figure 1the electrons in the pi system of the central ring react more like those of a standard diene.
For instance, in uncommon combinations involving X groups on both diene and dienophile, a 1,3-substitution pattern may be favored, an outcome not accounted for by a simplistic resonance structure argument.
Spectra tables go in the notebook, not in the typed portion. In order to avoid this, cyclopentadiene is kept on ice to prevent dimerization.
As the reflux was conducted, the reaction mixture appeared to darken a bit in color, and after 30 minutes, it was a distinct yellow color. Once you know the mass of the diene you have, then calculate the mass of maleic anhydride needed and use that amount.
Since this is a preparation, or synthesis, lab you must have reaction equations with structures in your notebook. Cis-Norbornene-5,6-endo-dicarboxylic anhydride Cyclopentadiene was previously prepared through the cracking of dicyclopentadiene and kept under cold conditions.
Show the calculation of any items for which you needed a calculator in your notebook in a clearly-labeled Calculations section. Obviously, you also need a procedure. The crystals were isolated through filtration in a Hirsch funnel.
Student Handout Additional Background: Calculation of the energy and orbital coefficients of the components' frontier orbitals  provides a picture that is in good accord with the more straightforward analysis of the substituents' resonance effects, as illustrated below.
Unlike dienes in open chains in which there is usually some proportion of the diene in the unreactive s-trans conformation, dienes in rings are held in the reactive conformation at all times by the constraints of the ring, making them react faster.
The diene component should be as electron-rich as possible.
Chlorosulfonyl isocyanate can be utilized as a dienophile to prepare the Vince lactam. Nonetheless, the yield of product is still low due to the following:(1) Read section of your text, The Diels-Alder Reaction of Dienes. (2) Review the technique of recrystallization by consulting your lab book from last year and the lab manuals available in.
The melting point analysis shows that the product of the Diels-Alder reaction was somewhat impure, but the product of the hydrolysis of the Diels-Alder adduct was very pure.
The yield of the reactions was also high; 89% and 75% for the two processes respectively.
Lab #4 May 26, Diels Alder Reaction Introduction: Diels Alder Reaction is the reaction of a diene with a species capable of reacting with the diene, the dienophile.
A diene is a hydrocarbon that contains two carbon double bonds, while a dienophile is an electron-deficient alkene. Cyclopentadiene is a good diene for the Diels-Alder reaction because of its substitution and its locked s-cis conformation.
Due to cyclopentadiene being substituted, the diene can draw on the electron density of the methylene in between the diene.
Instructions for Writing Laboratory Reports Organic II Lab, CHEM L Diels-Alder reaction of Cyclohexadiene and Maleic Anhydride 2, 3. Name, Lab Time, and Date[Self explanatory] A.M. Brilliant, MondayJanuary DEMO LAB REPORT Author: sarah l.
The Diels-Alder reaction is categorized as a pericyclic reaction, which involves the overlap of spatial orbitals as well as the hybridization and delocalization of the molecules.1 As a unique characteristic, this reaction is characterized as a concerted cycloaddition reaction indicating a lack of.Download