The cracking process requires a very high temperature of 300 c. Liquidphase cracking of dicyclopentadiene by reactive. The dicyclopentadiene dimer is cracked to the monomeric cyclopentadiene by. Type part of your institution name for a list of matches. Experiment 22 the dielsalder cycloaddition reaction pg. 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. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12. Dielsalder reaction with 1,4benzoquinones and subsequent retro dielsalder with elimination of cyclopentadiene have been used in synthesis of 2cyclohexene1,4diones. Cyclopentadiene cpd and dicyclopentadiene dcpd are two important products obtained from oil cracking, which are interconvertable through a dielsalder reaction. It is formed by diels alder reaction from two cyclopentadiene molecules and. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c10h12. In this article, we theoretically analyze the diels. Dcpd products originate from high temperature cracking of petroleum fractions and are best characterized as highly reactive intermediates used for a.
It is very possible that cyclopentadiene can dimerize. Dicyclopentadiene is coproduced in large quantities in the steam cracking of. An uncontrolled cracking of dcpd reverse diels alder reaction with. And also state whether they will be racemix, and draw its 3d configuration. 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. Heating dicyclopentadiene causes it to undergo a retro diels alder reaction to. What kind of reaction does the cracking of dicyclopentadiene represent. Alder cycloaddition between cyclopentadiene and c60 for which experimental results on energy barriers and reaction energies are known. Cracking of dicyclopentadiene chemistry stack exchange. Kinetic and thermodynamic control in the dielsalder reaction. A diels alder reaction is the reaction in which two new sigma bonds are formed from two pi bonds via the 1,4addition of a conjugated diene in the scis conformation to an alkene. In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser. Cyclopentadiene is an organic compound with the formula c 5 h 6.
Lestacdcpd is dicyclopentadiene resinor dcpd resin, the dimer of cyclopentadiene cpd formed by a diels alder addition reaction. At its simplest, this dimerisation can be described as a. At room temperature, it is a clear light yellow color liquid with an acrid odor. The purchased dicyclopentadiene was cracked at 160 c to produce. The diels alder reaction will be carried out on half the reaction scale given in the text book. However, this dielsalder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. Stripped to its most basic components, this reaction is represented by the addition of 1,3butadiene to ethene shown below. S1 supplemental materials solventfree diels alder reactions of in situ generated cyclopentadiene david huertas, melinda florscher and veljko dragojlovic wilkes honors college of florida atlantic university, 5353 parkside drive, jupiter, fl 33458, usa.
The kinetics of the dielsalder reaction of cyclopentadiene with bis2ethylhexyl maleate has been studied at temperatures between 25 and 100 c and at atmospheric pressure. Via the da reaction most microcracks can be healed. Cyclopentadiene dimerization and cracking dicyclopentadiene. Diels alder reactions of cyclopentadiene brainmass. The vapors are irritating to the eyes and respiratory system. Dielsalder reactions of neat reactive dienes and dienophiles are frequently. 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. Gas phase cracking of dicyclopentadiene to produce.
Jul 19, 2011 this week youll be creating a product via the dielsalder reaction. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10h12. 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. Above 150 c, dicyclopentadiene undergoes a retrodielsalder reaction at. Kinetic study of the dielsalder reaction of cyclopentadiene. A solventfree dielsalder reaction was carried out by heating a mixture of dicyclopentadiene and a dienophile. Keynes, the open university design and manufacture with polymers. Chapter 3 dielsalder and retro diels student theses faculty of. Cyclopentadiene is also a wellknown diene dienophile in dielsalder reactions. The customary laboratory source of 1, 3cyclopentadiene is a compound called dicyclopentadiene c 10 h 12 dicyclopentadiene is the diels alder cycloaddition product of two molecules of 1, 3cyclopentadiene. Search results for dicyclopentadiene at sigmaaldrich. To aid in product isolation, the entire reaction will.
Dcpd petroleum resins are pale yellow thermoplastic resin obtained from mainly polymerizing unsaturated dicyclopentadiene derived from c5 fraction, by products of petroleum cracking, through pretreatment, thermal polymerization and distillation. Cyclopentadiene is obtained by cracking of dicyclopentadiene 27 moffett, r. Pdf the first step on the dielsalder reaction between cyclopentadiene and maleic anhydride is actually a retro dielsalder. After learning about the reaction, i was able to complete a diels alder reaction in organic lab.
The diels alder retro diels alder concept is a powerful synthetic strategy in stereo and enantioselective routes to functionalized cycloalkenes. Nov 20, 20 the diels alder reaction solely refers to the above reaction, but by altering the diene and dienophile, the final product can be altered to something the chemist desires. Dicyclopentadiene dcpd, a dimer of cyclopentadiene, is a white crystalline chemical compound with camphorlike odor. Cracking of dicyclopentadiene and a process for the manufacture of high. The comparison of the results obtained with the twolayered oniom approach using different partitions for the high and lowlevel layers with those obtained employing the b3lyp631gd method for the entire. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms. I recently did a distillation of dicyclopentadiene bp 166 c to get cyclopentadiene bp 40 c. The dimer endodcpd can be formed easily at room temperature although full conversion takes several days 1.
Solventfree dielsalder reactions of in situ generated. Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. Trademark of the dow chemical company dow or an affiliated. The kinetics for direct and reverse dielsalder reactions has been. Cyclopentadiene, formed in situ, reacted with the dienophile in a.
These are compounds containing a nonaromatic closed ring of carbon atoms in which at least 2 atoms are connected by a double bond. Cyclopentadiene belongs to the class of organic compounds known as cycloalkenes. This thermal cracking is merely the reverse of the dielsalder reaction, thus it is called a retro dielsalder reaction. Cyclopentadiene and dicyclopentadiene wiley online library. Dielsalder reaction of cyclopentadiene and maleic anhydride savion.
Preparation of cyclopentadiene from its dimer journal of. At the boiling point of dicyclopentadiene, equilibration with the. Cyclopentadiene is a colorless liquid with an irritating, terpenelike odor. Most predominantly, dcpd molecules are formed and the product is further purified by vacuum distillation. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction.
Jan 25, 2012 what kind of reaction does the cracking of dicyclopentadiene represent. In the diels alder reaction of cyclopentadiene and maleicanhydride what are the two side reactions of cyclopenadiene and maleic anhydride not including the endo and exo major products. The dicyclopentadiene will be cracked for you by your t. Dielsalder reactions chemical and biomolecular engineering. Cyclopentadiene is one of the dienes frequently used in dielsalder reactions.
It is produced in bulk quantities through steam cracking of c5 petroleum products such as gas oils, naphtha, and crude oil. 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. Diels alder reaction with 1,4benzoquinones and subsequent retro diels alder with elimination of cyclopentadiene have been used in synthesis of 2cyclohexene1,4diones. The simplest diels alder reaction is the reaction of 1,3butadiene and ethylene to yield cyclohexene figure 1. 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. In a dielsalder reaction with cyclopentadiene and maleic. If your institution is not listed, please contact your librarian. Usually it is obtained by cracking of dicyclopentadiene and is used.
The influence of temperature on the kinetic constants was determined by fitting the results to the arrhenius equation. Cyclopentadiene and dicyclopentadiene cheung major. Dielsalder reaction of cyclopentadiene with maleic anhydride. This colorless liquid has a strong and unpleasant odor. The retro dielsalder reaction rda is the microscopic reverse of the dielsalder reactionthe formation of a diene and dienophile from a cyclohexene. You should notice that both of them have three double bonds. One molecule act as diene, the other as a dienephile. The alkene with which the diene reacts is called the dienophile, and the reaction proceeds best when there is a difference in the electron densities between the two. Summary the oligomerization of cyclopentadiene cpd and its dimer, dicyclopentadiene dcpd, to tricyclopentadiene tcpd through dielsalder reaction at temperatures between 120 and 150c was. 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. Dielsalder reaction of cyclopentadiene forms dicyclopentadiene dcpd, which has two isomers. Cyclopentadiene is made by thermal cracking of its dimer, and on standing it slowly reverts to this species. If the polymerization takes place inside a container, the container may violently rupture. To print or download this file, click the link below.