Most predominantly, dcpd molecules are formed and the product is further purified by vacuum distillation. Kinetic and thermodynamic control in the dielsalder reaction. Cracking of dicyclopentadiene chemistry stack exchange. Dielsalder reaction of cyclopentadiene and maleic anhydride savion. An uncontrolled cracking of dcpd reverse diels alder reaction with. 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. 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. After learning about the reaction, i was able to complete a diels alder reaction in organic lab. Trademark of the dow chemical company dow or an affiliated.
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. Preparation of cyclopentadiene from its dimer journal of. The kinetics for direct and reverse dielsalder reactions has been. Cyclopentadiene, formed in situ, reacted with the dienophile in a. Usually it is obtained by cracking of dicyclopentadiene and is used. Stripped to its most basic components, this reaction is represented by the addition of 1,3butadiene to ethene shown below. It is produced in bulk quantities through steam cracking of c5 petroleum products such as gas oils, naphtha, and crude oil. Cyclopentadiene cpd and dicyclopentadiene dcpd are two important products obtained from oil cracking, which are interconvertable through a dielsalder reaction. The dicyclopentadiene will be cracked for you by your t. Kinetic study of the dielsalder reaction of cyclopentadiene. Cyclopentadiene is an organic compound with the formula c 5 h 6.
Cyclopentadiene and dicyclopentadiene wiley online library. At the boiling point of dicyclopentadiene, equilibration with the. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c10h12. Cyclopentadiene is made by thermal cracking of its dimer, and on standing it slowly reverts to this species. Dielsalder reactions of neat reactive dienes and dienophiles are frequently. Keynes, the open university design and manufacture with polymers. Jan 25, 2012 what kind of reaction does the cracking of dicyclopentadiene represent. The dimer endodcpd can be formed easily at room temperature although full conversion takes several days 1. In a dielsalder reaction with cyclopentadiene and maleic. The vapors are irritating to the eyes and respiratory system.
The dicyclopentadiene dimer is cracked to the monomeric cyclopentadiene by. The diels alder retro diels alder concept is a powerful synthetic strategy in stereo and enantioselective routes to functionalized cycloalkenes. Dielsalder reactions chemical and biomolecular engineering. The retro dielsalder reaction rda is the microscopic reverse of the dielsalder reactionthe formation of a diene and dienophile from a cyclohexene. Cyclopentadiene dimerization and cracking dicyclopentadiene. If your institution is not listed, please contact your librarian. These are compounds containing a nonaromatic closed ring of carbon atoms in which at least 2 atoms are connected by a double bond. Above 150 c, dicyclopentadiene undergoes a retrodielsalder reaction at. Experiment 14 the dielsalder cycloaddition reaction pg. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction. 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.
Heating dicyclopentadiene causes it to undergo a retro diels alder reaction to. Jul 19, 2011 this week youll be creating a product via 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. It can be accomplished spontaneously with heat, or with acid or base mediation. Search results for dicyclopentadiene at sigmaaldrich. What kind of reaction does the cracking of dicyclopentadiene represent. Solventfree dielsalder reactions of in situ generated. Chapter 3 dielsalder and retro diels student theses faculty of.
Cyclopentadiene is also a wellknown diene dienophile in dielsalder reactions. Lestacdcpd is dicyclopentadiene resinor dcpd resin, the dimer of cyclopentadiene cpd formed by a diels alder addition reaction. However, this dielsalder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. The reaction kinetics of cyclopentadiene dimerization using. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms. One molecule act as diene, the other as a dienephile. 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. Cracking of dicyclopentadiene and a process for the manufacture of high.
This colorless liquid has a strong and unpleasant odor. It is very possible that cyclopentadiene can dimerize. A solventfree dielsalder reaction was carried out by heating a mixture of dicyclopentadiene and a dienophile. If the polymerization takes place inside a container, the container may violently rupture. Dicyclopentadiene dcpd, a dimer of cyclopentadiene, is a white crystalline chemical compound with camphorlike odor. Dielsalder reaction with 1,4benzoquinones and subsequent retro dielsalder with elimination of cyclopentadiene have been used in synthesis of 2cyclohexene1,4diones. The cracking process requires a very high temperature of 300 c. Diels alder reactions of cyclopentadiene brainmass. Dielsalder reaction of cyclopentadiene forms dicyclopentadiene dcpd, which has two isomers.
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. Dicyclopentadiene is coproduced in large quantities in the steam cracking of. Subject to polymerization if subjected to heat for prolonged periods or if contaminated. Based on dielsalder and retro dielsalder model reaction. This thermal cracking is merely the reverse of the dielsalder reaction, thus it is called a retro dielsalder reaction. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12. At its simplest, this dimerisation can be described as a.
Pdf the first step on the dielsalder reaction between cyclopentadiene and maleic anhydride is actually a retro dielsalder. Via the da reaction most microcracks can be healed. At room temperature, it is a clear light yellow color liquid with an acrid odor. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser. In this article, we theoretically analyze the diels. The simplest diels alder reaction is the reaction of 1,3butadiene and ethylene to yield cyclohexene figure 1. Liquidphase cracking of dicyclopentadiene by reactive.
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. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10h12. Diels alder reaction with 1,4benzoquinones and subsequent retro diels alder with elimination of cyclopentadiene have been used in synthesis of 2cyclohexene1,4diones. 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 with maleic anhydride.
Gas phase cracking of dicyclopentadiene to produce. 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. Cyclopentadiene is a colorless liquid with an irritating, terpenelike odor. Immobilized cyclopentadiene in the diels alderretrodiels. 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 purchased dicyclopentadiene was cracked at 160 c to produce. Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. 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. To aid in product isolation, the entire reaction will. I recently did a distillation of dicyclopentadiene bp 166 c to get cyclopentadiene bp 40 c. Cyclopentadiene belongs to the class of organic compounds known as cycloalkenes. 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. Experiment 22 the dielsalder cycloaddition reaction pg. Dcpd products originate from high temperature cracking of petroleum fractions and are best characterized as highly reactive intermediates used for a.
You should notice that both of them have three double bonds. 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. In conventional terminology, this is a 1,4addition of a diene and a dienophile. It is formed by diels alder reaction from two cyclopentadiene molecules and. Dicyclopentadiene dcpd 3a,4,7,7atetrahydo4,7methano1hindene c10h12 general dicyclopentadiene or dcpd is the dimer of cyclopentadiene cpd formed by a diels alder addition reaction. Type part of your institution name for a list of matches. 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. Dicyclopentadiene appears as a liquid with an acrid odor.
The diels alder reaction will be carried out on half the reaction scale given in the text book. 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. Cyclopentadiene and dicyclopentadiene cheung major. Cyclopentadiene is one of the dienes frequently used in dielsalder reactions. The influence of temperature on the kinetic constants was determined by fitting the results to the arrhenius equation. Cracking of dicyclopentadiene before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it.