Diels alder reaction of cyclopentadiene with maleic anhydride lab report. EXP 53 Diels 2022-12-22
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The Diels-Alder reaction is a classic chemical reaction that involves the combination of a conjugated diene and a dienophile to form a cyclohexene ring. One common example of this reaction is the Diels-Alder reaction of cyclopentadiene with maleic anhydride, which is the subject of this lab report.
To begin, cyclopentadiene and maleic anhydride are mixed together in a round-bottom flask equipped with a reflux condenser. The mixture is then heated to a temperature of around 80-100°C, depending on the specific reaction conditions. As the mixture is heated, the cyclopentadiene and maleic anhydride undergo a [4+2] cycloaddition, forming a cyclohexene ring and releasing a molecule of water.
The formation of the cyclohexene ring can be confirmed using infrared spectroscopy, which shows the characteristic absorption bands for the C=C and C=O bonds in the cyclohexene ring. The presence of the water molecule can also be confirmed by titration with a basic solution, as the maleic anhydride is converted to maleic acid upon hydrolysis.
The yield of the Diels-Alder reaction can be affected by a number of factors, including the reactant ratios, the reaction temperature, and the choice of solvent. In general, higher reaction temperatures and excess amounts of the dienophile (maleic anhydride in this case) tend to favor a higher yield of the cyclohexene product.
One important aspect of this reaction is the potential for side reactions to occur. For example, if the reaction mixture is not properly cooled, the cyclohexene product can undergo further reactions to form more complex products. In addition, the presence of oxygen or other impurities in the reaction mixture can lead to the formation of byproducts.
Overall, the Diels-Alder reaction of cyclopentadiene with maleic anhydride is a useful synthetic tool for the preparation of cyclohexene derivatives. By carefully controlling the reaction conditions, it is possible to obtain high yields of the desired product with minimal formation of byproducts.
EXP 53 Diels
At the same time, the experiment has retained its popularity in the Sophomore Organic Chemistry laboratory curriculum. In addition, it is important to discuss what the actual IR spectrum for anhydride should have looked like if the procedure was carried out without error. The mechanism for this is illustrated below in Figure 1. To prevent the side reaction, cyclopentadiene was produced via fractional Diels-Alder Reaction Lab Report In this experiment the objective was to perform a Diels-Alder reaction using cyclopentadiene and maleic anhydride to synthesize the product, cis-Norbornene-5,6-endo-dicarboxylic anhydride. This was done by adding diethyl amine drop wise using a seperatory funnel which resulted in a gas formation which was controlled with a condenser attached to a gas vacuum.
Figure 2: IR Spectrum of crystalized product Most of the values in this IR spectrum are in the fingerprint region and reveal useful data. Another important signal to look for is the bending, present at around This bending can be seen in the experimental IR obtained, but is not quite as pronounced as the experimenter should expect it to be. In order for a Diels-Alder reaction to occur the diene must exist as an s-cis conformation and must be conjugated. You will probably let it dry in your drawer for a week before you take a melting point and weigh your product for a percent yield. The Diels-Alder reaction is between 1,3-butadiene and ethylene to produce cyclohexene + dienedienophile.
Thiamine catalyst along with water and ethanol were added to the benzaldehyde, then NaOH was added until the solution turned yellow. In carbon-halogen bond, halogens have significantly greater electronegativities than carbon except iodine. As your swirl your flask the reaction will take place right away. And although it may seem tempting to believe that maleic anhydride can do that too, it is in an s- trans conformation, which isn't favorable in the Diels-Alder reaction, so I would only choose the cyclopentadiene dimerization as a plausible side product. Nitric acid was added to the benzoin and heated, this was followed by recrystallization to yield the benzil. In this experiment a reaction between anthracene and maleic anhydride will result in anhydride. Compound 50, like its known analogue 3, involves an α,β-unsaturated ketone, an acid-sensitive reactant, which prevents its direct synthesis in presence of protic solvents by refluxing.
These techniques were used to separate the Diels-Alder adduct of the unknown conjugated diene in eucalyptus oil and identify the diene. The mass of the anthracene used was 0 g. This ended the multistep synthesis. In result, this group is polarized so that the carbon is electrophilic and the halogen is nucleophilic. The reaction occurs via a concerted mechanism, meaning that it takes place all at once, with no isolatable intermediates. The reason the reagent is stored as a dimer is because as cyclopentadiene it is both a diene and a dienophile capable of reacting with itself. Put mineral oil in a 5 mL short-necked, round-bottomed flask until round portion is half full.
The theoretical melting point for tetraphenylcyclopentadienone 218-220 degrees Celsius. Below are some examples. Norbornene is a bridged cyclic hydrocarbon, this molecule contains a double bond that induces significant ring strain, and therefore, it is highly reactive. In the future, extra care should be taken to ensure a quality product in the lab, specifically when it comes to refluxing. After heating this, ethanoic KOH was added and the solution was left to reflux.
Let the maleic anhydride dissolve in the EtOAc, by heating if necessary. Hydration of alkenes is the acid-catalyzed addition of water to a carbon-carbon pi bond that leads to the formation of an alcohol. Then, add ~15 mL of hexane and let it cool in an ice bath. Additional time, more care setting up the experiment, and taking care to ensure heating and cooling baths are adequately prepared ahead of time could reduce such errors in the future. Once cool, obtain ~4mL of cold cyclopentadiene from your TA. This yielded substituted cyclohexene products.
When the diene is a ring such as cyclopentadiene " cp" or cyclohexadiene, the product will be bicyclic, with a bridge between C-3 and C-6. Then collect the product by vacuum filtration. The glass was washed with extra xylene, but it was not until after the samples were weighed that heated xylene was used to successfully wash the glassware and remove the excess crystals. Step two was the oxidation of benzoin to benzil. The classic dehydration of 2-methylcyclohexanol experiment that was introduced in Journal of Chemical Education in 1967 Taber 1967 JCE:44,p620. Diels-Alder reactions are useful in the creation of medicine, rubber, and plastic.
In fairly mild reaction conditions, the exo product is thermodynamically favorable, but the endo product is more kinetically favorable because of the above "secondary orbital interactions". However, the weighed mass of the product was 0 g. This phenomenon represents the side reaction of this experiment. THEORY: The Diels-Alder cycloaddition reaction was discovered by Otto Diels and Kurt Alder and is very useful in the synthesis of polycyclic compounds. To discover the product of this reaction, isolate the adduct, and classify the diene from the melting point of its adduct. This rotation cannot occur in the second molecule pictured as it is a that cannot be rotated or converted to a cis conformation. The final product was not successfully synthesized due to sources of error during procedures.
Diels-Alder Reaction of Cyclopentadiene with Maleic Anhydride to form cis-Norbornene 5,6-endo dicarboxylic acid anhydride Miaya Conyers Organic Chemistry Lab 145-05 2017 February Abstract Cis norbornene-5,6-endo-dicarboxylic anhydride was prepared in 83. The solution was lightly heated until the mixture fully dissolved, then the mixture was strongly heated until reflux. Basically, the high pi density in the maleic anhydride promotes this favorable overlap. There will still be two fully formed ring structures attached to either side of the final molecule. Add additional ice if needed but do not allow to get in flask.
