The synthesis of nbenzyl2azanorbornene via aqueous hetero diels alder reaction. Procedure place dicyclopentadiene 30 cm3 and a few antibumping granules in a 100 cm3 roundbottom flask and set up the apparatus for distillation, with the receiving flask in an icebath. At the boiling point of dicyclopentadiene, equilibration with the. Cyclopentadiene belongs to the class of organic compounds known as cycloalkenes. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser.
Insights into the dielsalder reactions between cyclopentadiene. This mixture was used for diels alder reactions on 3 terpenes and on cyclopentadiene in up to 100 g scale. And also state whether they will be racemix, and draw its 3d configuration. Diels alder reaction of cyclopentadiene and maleic anhydride from che 211l at quinnipiac university.
Dielsalder and melting point chem217labsfall07 openstax cnx. What was the purpose of adding paraffin to the reaction flask when cracking dicyclopentadiene. Jul 19, 2011 this week youll be creating a product via the dielsalder reaction. The conversion occurs in hours at room temperature, but the monomer can be stored for days at. You should notice that both of them have three double bonds. Cyclopentadiene is a useful diene in dielsalder reactions as well as a precursor to metallocenes in organometallic chemistry.
One such mechanismreaction is the dielsalder reaction, which i first learned. The journal of physical chemistry a 2006, 110 4, 12161224. A dielsalder reaction was used to produce the products of this experiment. The performance of density functional theory and hartree. Click the structures and reaction arrows in sequence to view the 3d models and animations respectively. In silico studies of structureproperty relationships of organic. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10h12. The c9c10 fraction formally contains all kinds of diels alder adducts because the various c5 diolefin molecules form dimers during the process steps of the ethylene manufacturing process. Notice that the product retains the same basic cyclohexene structure. The dielsalder reaction is a particularly useful method for the synthesis of compounds with cyclic structure. Diels alder reactions of cyclopentadiene brainmass. Synthesis of 5vinyl2norbornene based on the diels alder reactions of cyclopentadiene cpd generated from dicyclopentadiene dcpd and 1,3butadiene bd have been investigated in a.
The process of producing highpurity cyclopentadiene cpd has been investigated, including a gas phase thermal cracking process of dicyclopentadiene dcpd in the presence of h 2 on a continuous bed reactor and batch distillation for the further separation. A similar dielsalder system that is more easily studied is the dimerization of 1,3cyclopentadiene shown below. Cracking apparatus the diels alder reaction of cyclopentadiene with maleic anhydride the diels alder reaction that you will be performing between cyclopentadiene and maleic anhydride occurs rapidly at room temperature. This reaction has a great synthetic importance and was discovered by two german chemists, otto diels and kurt alder, who received the 1950 nobel prize. Kinetic and thermodynamic control in the dielsalder reaction. Dielsalder reactions chemical and biomolecular engineering. The major use is in resins, particularly, unsaturated polyester resins. In this lab we will be studying the reaction of cyclopentadiene with maleic anhydride. Synthesis of cisnorbornene5, 6endodicarboxylic anhydride introduction. The compound is unusually acidic pk a 16 for a hydrocarbon, a fact explained by the high stability of the aromatic cyclopentadienyl anion, c 5 h 5. Cyclopentadiene is an organic compound with the formula c 5 h 6. To crack the dicyclopentadiene, we used fractional distillation. The synthesis of nbenzyl2azanorbornene via aqueous hetero dielsalder reaction.
Cyclopentadiene is a colorless liquid with an irritating, terpenelike odor. To prepare substituted cyclopentadiene derivatives, we examined the reaction of norbornadiene derivatives 8al with a tetrazine 4 or 4. Raise the temperature of the heating mantle slowly until cyclopentadiene monomer collects slowly dropwise in the receiving flask. A microwave induced reaction of dicyclopentadiene 1 was used to rapidly and conveniently generate cyclopentadiene 2 which is stabilized in a polar solvent for subsequent use. Above 150 c, dicyclopentadiene undergoes a retrodielsalder reaction at. Procedure the apparatus for the cracking of dicyclopentadiene to cyclopentadiene will be set up in the hood and will be used to prepare all of the cyclopentadiene needed for the dielsalder reaction and for the preparation of ferrocene. Cracking apparatus the dielsalder reaction of cyclopentadiene with maleic anhydride the dielsalder reaction that you will be performing between cyclopentadiene and maleic anhydride occurs rapidly at room temperature. Write a mechanism for the formation of 1, 3butadiene from 3sulfolene or cyclopentadiene from dicyclopentadiene. Paraffin oil has a boiling point greater than 370 c. Propose a mechanism for the retro dielsalder reaction of dicyclopentadiene to give two. Nov 20, 20 after learning about the reaction, i was able to complete a dielsalder reaction in organic lab. Diels alder reactions can sometimes reverse themselves through retro diels alder reactions.
Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. Cyclopentadiene, formed in situ, reacted with the dienophile in a thermodynamically controlled reaction. And although it may seem tempting to believe that maleic anhydride can do that too, it is in an strans conformation, which isnt favorable in the diels alder reaction, so i would only choose the cyclopentadiene dimerization as a plausible side product. Solventfree dielsalder reactions of in situ generated. The hydrogen atoms in cyclopentadiene undergo rapid 1,5sigmatropic shifts as indicated by 1 h nmr spectra recorded at various. However, this diels alder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. Heating up the cp dimer with crack it back to the monomer. Kinetics of the thermal decompositions of exo and endodicyclopentadiene. What diene and what dienophile could be used to prepare each of the following. Insight into the informationalstructure behavior of the dielsalder. In conventional terminology, this is a 1,4addition of a diene and a dienophile. Dielsalder reactions are cycloadditions which occur between a diene and a conjugated alkene, known as the dienophile. This is the post lab questions for the diels alder. The majority of syntheses proceed with the formation of a mixture of isomers and the yield and reaction stereoselectivity depends to a large degree on the nature of solvent and catalyst.
Draw the products from the dielsalder reaction between. The polymer can be processed into films with very good transparency. Cracking of dicyclopentadiene chemistry stack exchange. There are at least two major reasons why the diels alder reaction is important in organic synthesis. Resin some components coloring petroleum resin in thermalcracked higher fractions.
Reaction mechanism the scheme below depicts the concerted mechanism of the dielsalder reaction of cyclopentadiene and maleic anhydride to form cisnorbornene5,6endodicarboxylic anhydride. In order to be of any use, the dimer must be cracked and distilled. Write a mechanism for the formation of 1, 3butadiene from. Draw the structure of the major product of the following reactions. In the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. Cyclopentadiene is an organic compound with the formula c5h6.
The reaction is reversible and at room temperature cyclopentadiene dimerizes over the course of hours to reform dicyclopentadiene. It is very possible that cyclopentadiene can dimerize. Solventfree diels alder reactions were carried out by heating a mixture of a volatile diene, such as 1,3butadiene, isoprene, or 2,3dimethyl1,3butadiene, and a dienophile, such as methyl vinyl. Structure, properties, spectra, suppliers and links for. We started with dicyclopentadiene which had to be cracked into cyclopentadiene. An undergraduate project in organic synthesis and structural analysis. Cracking of dicyclopentadiene before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it. All structures within the transient region were characterized and analyzed by means of geometrical descriptors, physicochemical parameters and informationtheoretical measures in order to observe the linkage between chemical behavior and. Stripped to its most basic components, this reaction is represented by the addition of 1,3butadiene to ethene shown below.
It can be accomplished spontaneously with heat, or with acid or base mediation. Chinese universities 2008,242, 17579 article id 10059040200802l7505 diels alder addition of dicyclopentadiene with cyclopentadiene in polar solvents zhang xiangwen, jiang qiang, xiong zhongqiang, zou jijun, wang li and mi zhentao key laboratory for green chemical technology of ministry of education, school of chemical engineering and. Give the structure of the product for each dielsalder reaction shown below. Draw curved arrow mechanism for the pericyclic reaction of cracking the dicyclopentadiene into two monomers of cyclopentadiene retro diels alder. Synthesis of cyclopentadiene trimer tricyclopentadiene over. This dimer can be restored by heating to give the monomer the compound is mainly used for the production of cyclopentene and its. Cyclopentadiene and dicyclopentadiene cheung major. This type of reaction was named for otto diels and kurt alder who were the first to investigate this reaction weldegirma, 2012. Experiment 14 the dielsalder cycloaddition reaction pg. In this case 2 was used for diels alder reactions at ambient temperature. In other words the answer is not the reaction between cyclopentadiene and maleic anhydride.
After learning about the reaction, i was able to complete a diels alder reaction in organic lab. Cyclopentadiene and dicyclopentadiene, which occur as byproducts in the steam cracking process in ethylene plants, are the major ingredients in the production of hydrocarbon resins, unsaturated polyester resins, elastomers, pesticides, flame retardants and a host of specialty chemicals. Most predominantly, dcpd molecules are formed and the product is further purified by vacuum distillation. This dimer can be restored by heating to give the monomer. The simplest diels alder reaction is the reaction of 1,3butadiene and ethylene to yield cyclohexene figure 1. If your institution is not listed, please contact your librarian. Please let a resonable explanation pertaining to diels alder reactions. However, this dielsalder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. To aid in product isolation, the entire reaction will.
Insight into the informationalstructure behavior of the. Although the elevated temperature can boost the cracking of dcpd into. Cyclopentadiene acts as the diene for the reaction. Gas phase cracking of dicyclopentadiene to produce. The first step on the dielsalder reaction between cyclopentadiene and maleic. Type part of your institution name for a list of matches. Synthesis of cyclopentadiene derivatives by retrodiels. The course of the diels alder reactions of cyclopentadiene and maleic anhydride were studied. The purpose of this experiment was to demonstrate the formation of sixmembered rings by cycloaddition, also known as a dielsalder reaction. Dielsalder reaction of cyclopentadiene and alkyl acrylates. Include the stereochemistry of the reaction and all major and minor products. Please let a resonable explanation pertaining to diels alder. Fock calculations for the prediction of substituent effects.
Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction. Procedure the apparatus for the cracking of dicyclopentadiene to cyclopentadiene will be set up in the hood and will be used to prepare all of the cyclopentadiene needed for the diels alder reaction and for the preparation of ferrocene. Retro diels alder reaction the reverse form of diels alder. Microwave induced preparations of incipient and solvent. Pdf insight into the informationalstructure behavior of. At its simplest, this dimerisation can be described as a. Dielsalder reaction of cyclopentadiene with maleic anhydride. Define the terms diene and dienophile as they apply to the dielsalder reaction.
The latter da adduct was subjected to a romp reaction catalysed by the grubbs ii catalyst. Structurereactivity relationships in homogeneous gasphase reactions. Draw the products from the diels alder reaction between cyclopentadiene and maleic anhydride. Organic chemistryintroduction to reactionsdielsalder.
Before that could be produced, dicyclopentadiene had to be cracked to get cyclopentadiene for the starting material. I recently did a distillation of dicyclopentadiene bp 166 c to get cyclopentadiene bp 40 c. This colorless liquid has a strong and unpleasant odor. The purpose of this experiment was to demonstrate the formation of sixmembered rings by cycloaddition, also known as a diels alder reaction. At room temperature, it is a clear light yellow color liquid with an acrid odor. The distillation temperature should not exceed 65 oc. Cracking cp you should be aware that cyclopentadiene cp will spontaneously react with itself, so it can only be stored as the dimer. Preparation of cyclopentadiene from its dimer journal of. The resulting polymer has some similarities to polynorbornene but is more polar. Cyclopentadiene readily undergoes other dielsalder reactions with dienophiles such as 1,4benzoquinone. Cycloaddition the diels alder reaction and hydrolysis of anhydrides. The retro dielsalder reaction rda is the microscopic reverse of the dielsalder reactionthe formation of a diene and dienophile from a cyclohexene. Diels alder reaction lab report conclusion essay example.
In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. A solventfree diels alder reaction was carried out by heating a mixture of dicyclopentadiene and a dienophile. Thermal cracking of dicyclopentadiene question part2. Subject to polymerization if subjected to heat for prolonged periods or if contaminated. The first reaction was cyclopentadiene with maleic anhydride to from the product of cisnorbornene5,6endodicarboxylic anhydride. Give the structure of the product for each diels alder reaction shown below. In a cycloaddition reaction, a 1,3diene reacts with an alkene, or dienophile, to produce a sixmembered ring. The dielsalder reaction is essentially a cycloaddition reaction cycloaddition reaction is. When pure cyclopentadiene is stored it also undergoes a diels alder cycloaddition reaction and forms. Define the terms diene and dienophile as they apply to the diels alder reaction. Answer in terms of generalities, not in terms specific to this lab. The dielsalder is unlike other organic reactions in that it doesnt involve any nucleophiles, leaving groups, or radicals, so there is no real mechanism to learn. In the cracking of dicyclopentadiene, why is it ne.
In this case both the diene and dienophile have stereochemistry. Dicyclopentadiene wikimili, the best wikipedia reader. Dielsalder reaction introduction identifying a diels. Dicyclopentadiene is coproduced in large quantities in the steam cracking of. If the polymerization takes place inside a container, the container may violently rupture. In a dielsalder reaction with cyclopentadiene and maleic. Above 150 c, dicyclopentadiene undergoes a retrodielsalder reaction at an appreciable rate to yield cyclopentadiene. Monomer and dimer are close enough in boiling point that a sloppy job will deliver a lot of dimer to the collection pot, which is a real pain to remove from many diels alder product mixtures. The vapors are irritating to the eyes and respiratory system. Alder reactions of cyclopentadiene and 9,10dimethylanthracene with cyanoalkenes. Cyclopentadiene trimer tricyclopentadiene is an important raw material during the synthesis of highenergydensity fuel. Experiment 2 organic chemistry ii pahlavancherif diels. Che 211l topics to be covered in the introduction section for expt. Besides being solventfree, the described procedure allows for almost complete utilization of dicyclopentadiene and avoids.
Cyclopentadiene and dicyclopentadiene, which occur as byproducts in the steam cracking process in ethylene plants, are the major ingredients in the production of hydrocarbon resins, unsaturated polyester resins, elastomers, pesticides, flame retardants and. Chinese universities 2008,242, 17579 article id 10059040200802l7505 diels alder addition of dicyclopentadiene with cyclopentadiene in polar solvents zhang xiangwen, jiang qiang, xiong zhongqiang, zou jijun, wang li and mi zhentao key laboratory for green chemical technology of ministry of education, school of chemical engineering and technology, tianjin university. The product is an interesting white crystalline structure that looks like snow. If you had conducted the reaction in a conical vial and then collected the crystals using a hirsch funnel, how do you think your percent yield would have changed. Dicyclopentadiene appears as a liquid with an acrid odor. These are compounds containing a nonaromatic closed ring of carbon atoms in which at least 2 atoms are connected by a double bond. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a diels alder reaction. Consecutive retro diels alder reactions played an important role in these synthetic pathways. Factors including cracking temperature, reaction time, and h 2 to dcpd ratios were studied.
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