Experimental procedure part a cracking of dicyclopentadiene part b diels alder from pcb 4531 at university of south florida. Cyclopentadiene is an organic compound with the formula c5h6. Cyclopentadiene article about cyclopentadiene by the free. Thus, when cyclopentadiene is obtained by cracking of dicyclopentadiene, one can. Dicyclopentadiene cracking process boulder scientific. To obtain cyclopentadiene monomer, commercial dicyclopentadiene is cracked by heating to 180 c. Dielsalder reaction of cyclopentadiene with maleic anhydride. The content, however, may differ, depending on the cause for the issuance of a. Cyclopentadiene dimerization and cracking dicyclopentadiene. Thus, when cyclopentadiene is obtained by cracking of dicyclopentadiene, one can expect, at best, an overall 6570% reaction yield with respect to dicyclopentadiene. Experimental procedure part a cracking of dicyclopentadiene.
Dicyclopentadiene is coproduced with ethylene from the c5 fraction in the steam cracking of naphtha and gas oils. Cyclopentadiene can be further purified by sequential dimerizations under carefully controlled slow heat soaking and subsequent monomerizations. Once a crack is found its important to repair it immediately using the procedures outlined in this bulletin. The dimerization accounts for the partial or complete solidification of liquid cyclopentadiene in storage. The yield, which is determined by weighing the receiving flask plus product, depends upon the quality. Cyclopentadiene was prepared by thermal cracking of dicyclopentadiene available. Preparation of cyclopentadiene from dicyclopentadiene. Catalytic enantioselective 1,4iodofunctionalizations of conjugated dienes.
Cracking tube 2 is a stainless tube with an internal diamer of 10 mm and a length of 1,000 mm, which is vertically installed and externally heated by heater 3 to an average cracking temperature of 350 c. Why is a 25ml rather than a 10ml roundbottom flask to be used for cracking dicyclopentadiene when only 7 ml of this substance is being cracked. However, this dielsalder reaction is reversible by cracking dicyclopentadiene using slow distillation and keeping the cyclopentadiene cold. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser. The experimental section will outline the procedure used to crack the cp dimer and the procedure for the preparation of the cpru pph 3 2 cl. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c10h12. Increasing temperature increases the rate of the dicyclopentadiene cracking reaction. Cyclopentadiene trimer tricyclopentadiene is an important raw material during the synthesis of highenergydensity fuel. Processes and systems for making cyclopentadiene andor dicyclopentadiene include converting acyclic c5 hydrocarbons into cpd in a first reactor in the presence of a c1c4 cofeedstock to obtain a product mixture, separating the product mixture in a separation subsystem such as compression train to obtain a c5rich fraction comprising cpd and essentially depleted of hydrogen and c1c4. Process and system for making cyclopentadiene andor dicyclopentadiene. They are obtained from coal tar about 1020 gtonne and by steam cracking of naphtha about 14 kgtonne. Its name derives from the molecule cyclopentadiene. In conventional terminology, this is a 1,4addition of a diene and a dienophile.
The process for the production of cyclopentadiene by the substantially quantitative splitting or monomerizing of a dicyclopentadiene concentrate containing thermally stable dimers of isoprene and codimers of cyclopentadiene, isoprene and piperylene and having been obtained by the heat treatment of a c5 fraction of a pyrolysis petrol and its subsequent enrichment by fractional distillation. Also i would freeze the collected cyclopentadiene during collection and storage. The optical purity is 89% ee based on comparison with an authentic sample and. Experiment 22 the dielsalder cycloaddition reaction pg. Cyclopentadiene and other cshydrocarbons are recovered from the cracked product by a series of distillations. Backward reaction shows the cracking of dicyclopentadiene to give 1,3cyclopentadiene.
Cyclopentadiene, a reagent commonly used in organic synthesis, is known to spontaneously dimerize exothermically and thus should be stored cold and used quickly. To aid in product isolation, the entire reaction will. Dcdp is used as a building block for the production of modified hydrocarbon resins, which show increased reactivity in copolymerizations with drying oils and produce paint resins with improved drying rate, gloss, and hardness. Working with hazardous chemicals organic syntheses. Why does 1,3 cyclopentadiene react more rapidly with maleic anhydride than with another molecule of itself. This content was copied from view the original, and get the alreadycompleted solution here. You must detail how the compounds will be synthesized, including diagrams for the synthetic apparatusi needed for your experiment. At its simplest, this dimerisation can be described as a. Cyclopentadiene production is usually not distinguished from dicyclopentadiene since they are interconverted. Introduction conjugated dienes undergo a cycloaddition reaction with multiple bonds to form unsaturated sixmembered rings. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Free template downloads free microsoft word, excel and. Its a good idea to keep it cold at this point since low temp slows the dimerization. Mar 02, 1999 a process and a system for cracking dicyclopentadiene are disclosed pursuant to the process preheated dicyclopentadiene is introduced into a heated transfer fluid sufficiently below the transfer fluid surface to accomplish substantially complete conversion of said dicyclopentadiene to monomeric cyclopentadiene vapor.
Process for producing cyclopentadiene and its homologues. Links with this icon indicate that you are leaving the cdc website the centers for disease control and prevention cdc cannot attest to the accuracy of a nonfederal website. Cyclopentadiene c10h10fe or c5h5fec5h5 or fec10h10 or c5h6 cid 7612. Preparation of cyclopentadiene from its dimer journal of. 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. Cyclopentadiene, in its turn, is obtained from coal tar and from steam cracking operations. Dicyclopentadiene cracking process boulder scientific company. Synthesis of cyclopentadiene trimer tricyclopentadiene. Haagensmit laboratory, procedure for the detailed hydrocarbon analysis of gasolines by single column high efficiency capillary.
The report must include a schematic of the reactions. In this case, cracking means heating the dimer until it undergoes a retrodielsalder reaction. It is either a clear liquid or solid, with a sweet odor like turpentine or camphor. The sensitivity is determined by the slope of the calibration curve see figure 3. Romp reactivity of endo and exodicyclopentadiene joseph d. Besides being solventfree, the described procedure allows for almost. The cracking process requires a very high temperature of 300 c. Free microsoft word, excel and publisher templates.
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. Typically the formats and patterns of all hr warning letters are nearly the same. The process of producing highpurity cyclopentadiene cpd has been. Cyclopentadiene pyrolysis is a process studied extensively due to the potential role of cyclopentadiene as an intermediate molecule in the generation of pahs during the pyrolysis of many other organic compounds 915. The groundglass note 3 outlet of the friedrichs condenser is connected to the side arm of a simple distilling head fitted. The major use is in resins, particularly, unsaturated polyester resins. Procedure for preparing cyclopentadiene from its dimer. Organometallic complexes that include both the cyclopentadienyl anion and cyclopentadiene itself are known, one example of which is. This procedure largely avoids the codimerization of cyclopentadiene with residual unsaturated c5 impurities, allowing the latter to be removed from dicyclopentadiene by stripping. The purity of cyclopentadiene obtained by this way is more than 99%. Cyclopentadiene is produced during the carbonization of coal, and as a byproduct of thermal cracking of hydrocarbons such as gas oil and naphtha in the presence of steam. The three principal rawmaterial streams to produce hcr are linear c5s such as piperylene and amylene, cyclic c5s such as cyclopentadiene, and aromatic c9 and c10 fractions, heavy in reactive monomers such as styrene. The largest consumption of dicyclopentadiene is linked to the production of resins including unsaturated polyester resins, petroleum resins, terpolymers, polynorbornenes, and other cyclic olefin polymers.
Linking to a nonfederal website does not constitute an endorsement by cdc or any of its employees of the sponsors or the information and products presented on the website. Write an equation that shows the equilibrium process in. To aid in product isolation, the entire reaction will be. Diels alder reactions of cyclopentadiene brainmass. Dielsalder reaction of cyclopentadiene with maleic anhydride johnson, chad philip. When drafting a nondisclosure agreement, there are several factors you must consider in order protecting all parties involved.
Cyclopentadiene and dicyclopentadiene cheung major. Also, when cooling a piece of equipment that contains the hot bottoms from the distillation or cracking of dicyclopentadiene, care should be taken to exclude air. The first step on the dielsalder reaction between cyclopentadiene and. This procedure is essentially the same as that described in the literature. In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowly. The mass of cyclopentadiene that was collected was 0. Cdc niosh pocket guide to chemical hazards cyclopentadiene.
I recently did a distillation of dicyclopentadiene bp 166 c to get cyclopentadiene bp 40 c. The dicyclopentadiene dimer c10h12 is broken down cracked to the. The experimental procedure of obtaining cyclopentadiene followed the work from magnusson and eastwood and coworkers. Cracking apparatus the dielsalder reaction of cyclopentadiene with maleic anhydride. Cyclopentadiene, which is obtained from a light oil distilled from coal, is a very reactive diene and dienophile, so it readily dimerizes at room temperature to form dicyclopentadiene. Processes and systems for making cyclopentadiene andor dicyclopentadiene include converting acyclic c5 hydrocarbons into cpd in a first reactor to obtain a first reactor hydrocarbon effluent, which is processed in an eductor to obtain an eductor effluent at higher total pressure than atmospheric pressure, separating the eductor effluent in a separator such as compression train to obtain a. At the end of the experiment, we obtain the desired crystal of cisnorbornene5,6endodicarboxylic anhydride. However, the equilibrium between the monomer and dimer can be established at the boiling point of the dimer by a process called cracking. Dicyclopentadiene is coproduced in large quantities in the steam cracking of. The initiation reaction for cyclopentadiene pyrolysis starting around 600c is the formation of the cyclopentadienyl radical. Moore the beckman institute for advanced science and technology and department of chemistry, university of illinois, urbana, illinois 61801 received june 17, 2002. Cyclopentadiene and 3chlorocyclopentene cyclopentene, 3chloro submitted by robert bruce moffett1 checked by r.
Characterization of the proteins from vigna unguiculata seeds. Cyclopentadiene wisconsin department of health services. The process of producing highpurity cyclopentadiene cpd has been investigated, including a gas phase thermal cracking process of dicyclopentadiene dcpd in the presence of h2 on a continuous. At room temperature, it is a clear light yellow color liquid with an acrid odor. This thermal cracking is merely the reverse of the dielsalder reaction, thus it is called a retro dielsalder reaction.
The dielsalder reaction that you will be performing between cyclopentadiene and maleic anhydride occurs rapidly at room temperature. The pure cyclopentadiene was obtained by cracking the dimer. When ive done it in the past ive had my setup under flowing n2 to keep it dry, but the drying tube could work depending on how pure you need it. Cyclopentadiene is very easy to polymerize and the purity of it after long time decreases remarkably, so it must be used as. Before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it. The cyclopentadiene cpd molecules, from which dcpd products are made, originate from high temperature cracking of petroleum fractions in an ethylene manufacturing process. Dcpd products from dow can best be characterized as highly reactive intermediates used for a wide range of resins, i. Dicyclopentadiene should never be distilled to dryness since there is danger of explosion if peroxides are present. The potential hazards from cyclopentadiene storage and use on kilogram scale are studied under adiabatic conditions. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10 h 12. Cyclopentadiene is not commonly found in a home environment, although it is found in tobacco smoke and car exhaust. Gas phase cracking of dicyclopentadiene to produce.
The reaction is strongly exothermic hazardous chemicals desk reference, p. Cyclopentadiene dimerizes rapidly at room temperature and should be used immediately note 5 or stored at dry ice temperatures. Dicyclopentadiene is coproduced in large quantities in the steam cracking of naphtha and gas oils to ethylene. In order to issue a first written warning letter, you can easily make use of this template, which has been kept exact and precise. Following the general procedure of example 1, but wherein the steam was also utilized. Therefore, a procedure that allows use of dicyclopentadiene directly would have important practical advantages. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or longchain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carboncarbon bonds in the precursors. For example, in the presence of sulfuric acid, water adds to dcpd to form the exo secondary alcohol.
For example, the reaction converting c5 hydrocarbons to cpd is extremely. August 27, 2014 the dow chemical company page 1 of 6. Welding repair for structural cracks allied systems. Typical 8h twa 200 mgm3 75 ppm risk phrases the meaning of any risk phrases which appear in this section is given here.
Manufacturers use cyclopentadiene to make resins and other chemicals. The largest consumption of dicyclopentadiene is linked to the production of resins including unsaturated polyester resins, petroleum resins, terpolymers, polynorbornenes, and. This and other undesirable side reactions are to be avoided if high yields of cyclopentadiene monomer are to be obtained. Solventfree dielsalder reactions of in situ generated. Us3719718a process for the production of cyclopentadiene. 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. As obtained above, the product has a refractive index of about 1. Over the years we have observed many successful and unsuccessful attempts to repair cracks. Experiment 14 the dielsalder cycloaddition reaction pg. As for the necessity for the slow cracking of cyclopentadiene, i believe its a compromise between obtaining pure cyclopentadiene efficient slow fractional distillation and throughput rate of collection of distilate. This procedure largely avoids the codimerization of cyclopentadiene with. Toxic by ingestion, inhalation or through skin contact.
Structure, properties, spectra, suppliers and links for. One object of the invention is to provide a process of the foregoing type which is. Dcpd is a dimer of cyclopentadiene cpd and is formed during hightemperature cracking. The sensitivity of the analytical procedure over a concentration range of 0. Abstract cyclopentadiene and dicyclopentadiene, which occur as byproducts in the steam cracking process in ethylene. Cyclopentadiene, which will be used in this experiment cannot be purchased commercially, and must be prepare in the lab by thermally cracking dicyclopentadiene. This service procedure was developed to outline proper crack repair procedures procedures.