Unlike the conventional method depending on retro dielsalder reaction of dicyclopentadiene to generate indirectly cyclopentadiene, the method of the present invention favors generation of cyclopentadiene. A reactive distillation process was developed for cracking dicyclopentadiene dcpd to produce cyclopentadiene cpd. In the autoclave reactor, reaction temperature, reaction time, diluent, and inhibitors are investigated to study the effect of inhibiting oligomerization reactions. Search results for dicyclopentadiene at sigmaaldrich. For instance, the reaction between cpd and maleic anhydride. As dicyclopentadiene enters the air, it breaks down quickly into simpler, lesstoxic chemicals.
At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction. Light hydrocarbon feeds such as ethane, lpgs or light naphtha give product streams rich in the lighter alkenes, including ethylene, propylene, and butadiene. The objective of this experiment was to crack dicyclopentadiene into two molecules of cyclopentadiene and mix cyclopentadiene with maleic anhydride to synthesize. I saw in books that reaction between dicyclopentadiene and maleic acid result in dicyclopentadienemaleat ester. The present invention relates to a synthesis method of metal cyclopentadienide by direct reaction of dicyclopentadiene with a group 1 metal in the presence of an aprotic solvent. Can undergo exothermic polymierization reactions in the presence of various catalysts such as acids or initiators. Vapor phase cracking of dicyclopentadiene and synthesis of. Although the exo form of the molecule is thermodynamically more stable, commercial dcpd products contain mostly the endo molecule as it forms much faster than the exo form. The process of cracking dicyclopentadiene to produce cyclopentadiene using hydrogen as a carrier gas is investigated. It is formed by diels alder reaction from two cyclopentadiene molecules and exists in two stereoisomers.
If you were to attempt to distill the monomer from the dimer at say 60 c it would probably take a very long time due to the slow rate of monomer formation at that. High yields of dielsalder products were obtained without using solvents and catalysts within a short reaction time in most of. At the boiling point of dicyclopentadiene, equilibration with the monomer is rapid. As there was some foaming in the course of the reaction, it may be. Its a colorless, waxy, flammable solid or liquid, with a camphorlike odor. Four groups, each consisting of 45 male and 45 female b6c3f1 mice, were exposed to dicyclopentadiene vapor by inhalation 6 hrday, 5 daysweek, for weeks 64 exposures at targeted concentrations of 0, 1. C, reaction time up to 4 s, and h2 to dcpd ratio varied within. Shorter reaction times resulted in an incomplete reaction, while longer reaction times gave charred products and lower yields. The dimer endodcpd can be formed easily at room temperature although full conversion takes several days. After all of the cyclopentadiene has been added, the mixture will cool, and crystals should start to form. 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. Gasphase cracking dicyclopentadiene using hydrogen as a. Factors including cracking temperature, reaction time, and h2 to dcpd ratios were studied.
The reaction is strongly exothermic hazardous chemicals desk reference, p. Figure one demonstrates the fractional distillation set up which was used to crack dicyclopentadiene. This reaction is exothermic, thus the reaction mixture may need to be cooled in an ice bath. And also state whether they will be racemix, and draw its 3d configuration. The reaction is reversible and at room temperature cyclopentadiene dimerizes over the course of hours to reform dicyclopentadiene. Dicyclopentadiene dcpd 3a,4,7,7atetrahydo4,7methano1hindene c10h12 general dicyclopentadiene or dcpd is the dimer of cyclopentadiene cpd formed by a dielsalder addition reaction. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms. At room temperature, it is a clear light yellow color liquid with an acrid odor. This colorless liquid has a strong and unpleasant odor. The largest consumption of dicyclopentadiene is linked to the production of resins including unsaturated polyester resins, petroleum resins, terpolymers, polynorbornenes, and. The yields of the oligomers at various temperatures and contact times are shown in table 3. Improved process for vapor phase cracking of dicyclopentadiene and synthesis of 2,3dihydrodicyclopentadiene therefrom.
For the batch distillation, the satisfactory results. Cyclopentadiene c5h6 reacts with itself to form dicyclopentadiene c10h12. Cyclopentadiene from its polymer patents and patent. Stripped to its most basic components, this reaction is represented by the addition of 1,3butadiene to ethene shown below. Dicyclopentadiene wisconsin department of health services. In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. An assessment of toxicity is carried out after 2, 6, and weeks of inhalation exposures.
Initially, a feedstock consisting essentially of dicyclopentadiene and cyclopentene is subjected to thermocracking in the vapor phase, resulting in the conversion of dicyclopentadiene to monomeric cyclopentadiene. Solved cyclopentadiene c5h6 reacts with itself to form. Liquid phase cracking of dicyclopentadiene by reactive distillation. Liquidphase cracking of dicyclopentadiene by reactive. In its highly purified form, it can be polymerised by the so called metathesis chemical reaction which gives rise to a crosslinked 3dimensional polymer structure. This new compound must be separated before the desired compound can be used.
Dicyclopentadiene, or dcpd, is a product obtained from the steamcracking process. Dcpd products originate from high temperature cracking of petroleum fractions and are best characterized as highly reactive intermediates used for a. Safety data sheet crude dicyclopentadiene version 2. Gas phase cracking of dicyclopentadiene to produce.
Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. We started with dicyclopentadiene which had to be cracked into cyclopentadiene. The introduction of auxiliary diluent and inhibitors prevents the oligomerization reactions. Undergoes a spontaneous dimerization at room temperature to give dicyclopentadiene c10h12, cas no. The dimer endodcpd can be formed easily at room temperature although full conversion takes several days 1. To crack the dicyclopentadiene, we used fractional distillation, which involves boiling the mixture to remove a certain compound by recondensing it. Dielsalder reaction of cyclopentadiene with maleic anhydride. It will dissolve in water and evaporates quickly from water and soil surfaces. Cyclopentadiene acts as the diene for the reaction. Cracking of dicyclopentadiene chemistry stack exchange. Subject to polymerization if subjected to heat for prolonged periods or if contaminated. The major use is in resins, particularly, unsaturated polyester resins. Dicyclopentadiene products a guide to product handling and use disclaimer the information, specification, procedures, methods and recomme ndations herein are presented in good faith, are believed to be.
The study focused on the effect of the reaction time, reaction temperature, the use of a diluent and inhibitors on the inhibition of oligomerization reactions. The reaction of cyclopentadiene with methyl acrylate and ethyl acrylate proceeded very fast in the medium of 1butyl1methylpyrrolidinium trifluoromethanesulfonates pyrr 1. Another method of producing cpd is by cracking the dcpd in the. In the past few decades, dicyclopentadiene dcp has received significant attention as a monomer for ring opening metathesis polymerization romp. This process has many advantages over using n 2 or water vapor as a carrier gas for producing anhydrous polymerization level dicyclopentadiene.
Factors including cracking temperature, reaction time, and h 2 to dcpd ratios were studied. Dicyclopentadiene is coproduced with ethylene from the c5 fraction in the steam cracking of naphtha and gas oils. No workplace exposure level could be found in the literature but dicyclopentadiene is used as an intermediate for cyclodiene pesticides. The adducts are important precursors to natural products, as discussed in a later section. Solventfree dielsalder reactions of in situ generated. The products produced in the reaction depend on the composition of the feed, the hydrocarbontosteam ratio, and on the cracking temperature and furnace residence time. Cracking of dicyclopentadiene before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12.
And they said this is and ene reaction but i couldnt understand how this reaction is subset of ene reaction and how ester group is made. The reaction kinetics of cyclopentadiene dimerization. Experiment 14 the dielsalder cycloaddition reaction pg. If the polymerization takes place inside a container, the container may violently rupture. The first step on the dielsalder reaction between cyclopentadiene and maleic. Above 150 c, dicyclopentadiene undergoes a retrodielsalder reaction at an appreciable rate to yield cyclopentadiene. What kind of reaction does the cracking of dicyclopentadiene represent. Alder reactions of dienophiles and cyclopentadiene using. Cyclopentadiene and dicyclopentadiene cheung major. Cyclopentadiene cpd and dicyclopentadiene dcpd are two important products obtained from oil cracking 1, which are interconvertable through a dielsalder reaction. However, it can stay unchanged for a long time in soil and in. Mcmaster university chem3d03 lab manual experiment 6. Dielsalder reactions chemical and biomolecular engineering.
Results show that the optimal cracking conditions of. The 2,4disubstituted products 64a,b, obtained stereoselectively via the extended and compact mode, respectively, are usually a mixture of two cis isomers except for the. Cyclopentadiene is an organic compound with the formula c 5 h 6. Us3007978a us836500a us83650059a us3007978a us 3007978 a us3007978 a us 3007978a us 836500 a us836500 a us 836500a us 83650059 a us83650059 a us 83650059a us 3007978 a us3007978 a us 3007978a authority us united states prior art keywords cracking cyclopentadiene wt percent process prior art date 19590827 legal status the legal status is an assumption and is not a. The appearance of crystals white crystalline powder c. The rate of monomer formation cracking becomes reasonable at temperatures above 150 c and approaching the boiling point of the dimer. Rather than cracking dicyclopentadiene in a separate.
Cyclopentadiene dimer chemical reference number cas. If none have formed by the time the solution reaches room temperature, add 8 ml of hexane or petroleum ether. To aid in product isolation, the entire reaction will. In the autoclave reactor, reaction temperature, reaction time, diluent, and inhibitors are investigated to study the effect of inhibiting oligomerization. Diels alder reactions of cyclopentadiene brainmass. Factors, including cracking temperature, reaction time, and h 2 to oil ratio, are studied.
Heating up the cp dimer with crack it back to the monomer. 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. If none have formed by the time the solution reaches room temperature, add 8 ml of hexane or petroleum. Cyclopentadiene cpd and dicyclopentadiene dcpd are two important products obtained from oil cracking, which are interconvertable through a dielsalder reaction. The ld 50 for dicyclopentadiene given rats is 353 mgkg. Us patent for process for the vaporphase thermal cracking. Cracking cp you should be aware that cyclopentadiene cp will spontaneously react with itself, so it can only be stored as the dimer. The results of reaction of cyclopentadiene with selected alkyl acrylates scheme 1 in ionic liquids as the reaction medium without the catalyst were presented in table 1. The reaction product has been claimed to be solely endodcpd. The vapors are irritating to the eyes and respiratory system. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms dicyclopentadiene. Dicyclopentadiene appears as a liquid with an acrid odor. Its low cost, high reactivity, and tendency to form tough, highly crosslinked materials have made it a good choice.
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