Dicyclopentadiene is classified as moderately toxic. For example, in the present experiment it is the cracking of cyclopentadiene dimer to cyclopentadiene monomer. Abstract the objective of this experiment was to crack dicyclopentadiene to create two molecules of cyclopentadiene, and then perform a dielsalder reaction by reacting the diene with maleic anhydride, the dienophile, to create cisnorbornene5,6endodicarboxylic anhydride. Draw the structure of the product of cyclopentadiene dimerization. Preparation of cyclopentadiene from its dimer journal of. This dimer can be restored by heating to give the monomer. Most predominantly, dcpd molecules are formed and the product is further purified by vacuum distillation. Results and discussion when combining the reagents, a cloudy mixture was produced and problems arose in the attempt to completely dissolve the mixture. Cyclopentadiene acts as the diene for the reaction. Cyclopentadiene cpd and dicyclopentadiene dcpd are two important products obtained from oil cracking, which are interconvertable through a dielsalder reaction.
In the cracking of dicyclopentadiene, why is it ne. 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. Cyclopentadiene is an organic compound with the formula c5h6. Dicyclopentadiene dioxide, mixture of endo and exo isomers. This colorless liquid has a strong and unpleasant odor. At the boiling point of dicyclopentadiene, equilibration with the.
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. Experiment 14 the dielsalder cycloaddition reaction pg. Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. Dicyclopentadiene appears as a liquid with an acrid odor. However, this dielsalder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Organic chemistryintroduction to reactionsdielsalder. Cyclopentadiene and dicyclopentadiene cheung major. An undergraduate project in organic synthesis and structural analysis. It is very possible that cyclopentadiene can dimerize.
To aid in product isolation, the entire reaction will. A reexamination of the molecular mechanism of the diels. Synthesis of 5vinyl2norbornene based on the dielsalder reactions of cyclopentadiene cpd generated from dicyclopentadiene dcpd and 1,3butadiene bd have been investigated in a. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms. Synthesis and characterization of hydrogenated sorbic acid. The dielsalder reaction is one of the most interesting and useful reactions found in organic chemistry in 20 th century. The vapors are irritating to the eyes and respiratory system. Dielsalder reactions chemical and biomolecular engineering. Dft calculation results shed a new light on the mechanism of cycloaddition reaction between tetrafluoroethene and cyclopentadiene. The mass of cyclopentadiene that was collected was 0. Cyclopentadiene belongs to the class of organic compounds known as cycloalkenes.
For example, dicyclopentadiene can be cracked to form 1,3cyclopentadiene by thermal dissociation. If the polymerization takes place inside a container, the container may violently rupture. Because it start distilling at a temperature 4042 c and before reaching this temperature it cant be distilled. 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. 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. In a dielsalder reaction with cyclopentadiene and maleic.
Cyclopentadiene can act as a dielsalder diene and as a dienophile. Retro reactions occur under situations where the fragments are stable by themselves. 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. One molecule act as diene, the other as a dienephile. The dimer endodcpd can be formed easily at room temperature although full conversion takes several days. Diels alder reactions of cyclopentadiene brainmass. 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. Cracking of dicyclopentadiene chemistry stack exchange. Hydrocarbon resins, which are defined as low molecular weight, amorphous, and thermoplastic polymers, are widely used as tackifier for various types of adhesives, as processing aids in rubber compounds, and as modifiers for paint and ink products, and for plastics polymers such as isotactic polypropylene. After learning about the reaction, i was able to complete a dielsalder reaction in organic lab. Heating dicyclopentadiene causes it to undergo a retro dielsalder reaction to give 1,3cyclopentadiene. What kind of reaction does the cracking of dicyclopentadiene represent. Revisiting the stability of endoexo dielsalder adducts. Synthesis of cisnorbornene5, 6endodicarboxylic anhydride introduction.
These are compounds containing a nonaromatic closed ring of carbon atoms in which at least 2 atoms are connected by a double bond. The reaction product has been claimed to be solely endodcpd. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12. We started with dicyclopentadiene which had to be cracked into cyclopentadiene. More information on molar mass and molecular weight. The major use is in resins, particularly, unsaturated polyester resins. Heating up the cp dimer with crack it back to the monomer. Please let a resonable explanation pertaining to diels alder reactions.
Dicyclopentadiene wikimili, the best wikipedia reader. In conventional terminology, this is a 1,4addition of a diene and a dienophile. At room temperature, it is a clear light yellow color liquid with an acrid odor. The ld 50 for dicyclopentadiene given rats is 353 mgkg.
Immobilized cyclopentadiene in the diels alderretrodiels. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction. The construction of sixmembered rings built from a fragment of four. 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 dielsalder reaction, so i would only choose the cyclopentadiene dimerization as a plausible side product. Klunder department of organic chemistry, nsrim, university of nijmegen, toernooiveld 1, 6525 ed nijmegen, the netherlands email. Dielsalder reaction of cyclopentadiene with maleic anhydride. When pure cyclopentadiene is stored it also undergoes a diels alder cycloaddition reaction and forms.
Zhi cai, benxian shen, weilian liu, zhong xin and hao ling. Solventfree dielsalder 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. Recommended st values differ from other statistically calculated values turnbull a. There is an excellent agreement between selected values of st and cpt and those obtained by ab initio calculation. It is the prototypical example of a pericyclic reaction with a concerted mechanism. Cracking of dicyclopentadiene before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it. In chemistry, the formula weight is a quantity computed by multiplying the atomic weight in atomic mass units of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all. The course of the dielsalder reactions of cyclopentadiene and maleic anhydride were studied. The reaction kinetics of cyclopentadiene dimerization. In organic chemistry, the dielsalder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile also spelled dieneophile, to form a substituted cyclohexene derivative. Liquidphase cracking of dicyclopentadiene by reactive distillation. Dielsalder reactions can sometimes reverse themselves through retrodielsalder reactions. Chinese universities 2008,242, 17579 article id 10059040200802l7505 dielsalder 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. Insight into the informationalstructure behavior of the.
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. Reaction mechanism the scheme below depicts the concerted mechanism of the dielsalder reaction of cyclopentadiene and maleic anhydride to form cisnorbornene5,6endodicarboxylic anhydride. You should notice that both of them have three double bonds. 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. In organic chemistry, the diels alder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile also spelled dieneophile, to form a substituted cyclohexene derivative. This type of reaction was named for otto diels and kurt alder who were the first to investigate this reaction weldegirma, 2012. Stripped to its most basic components, this reaction is represented by the addition of 1,3butadiene to ethene shown below. The synthesis of nbenzyl2azanorbornene via aqueous hetero dielsalder reaction. At its simplest, this dimerisation can be described as a. However, this diels alder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. The simplest dielsalder reaction is the reaction of 1,3butadiene and ethylene to yield cyclohexene figure 1.
Cracking of dicyclopentadiene performed by your instructor, see figure l 2. Cyclopentadiene is a colorless liquid with an irritating, terpenelike odor. Cyclopentadiene is made by thermal cracking of its dimer, and on standing it slowly reverts to this species. Experiment 5 cisnorbronene5,6endodicarboxyiic acid by dielsaider reaction part a. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser. Cracking cp you should be aware that cyclopentadiene cp will spontaneously react with itself, so it can only be stored as the dimer. 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. At the same time, the competitive and independent path leads to a onestep and. Subject to polymerization if subjected to heat for prolonged periods or if contaminated.