Cyclopentadienemaleimide platform for thermally reversible polymers jeremy brent stegall abstract this dissertation describes a new platform for the synthesis of thermally reversible polymers, based on dielsalder reactions of biscyclopentadienes biscpds and. Direct observation of cyclopentadiene formation via cyclohexadienone, author scheer, adam m. Draw the reaction mechanism for the thermal cracking of dicyclopentadiene. Polymerization occurs more rapidly and extensively at higher temperatures. Cyclopentadiene and dicyclopentadiene researchgate. Dielsalder reaction of cyclopentadiene with maleic anhydride. 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. Cyclopentadienic compounds as intermediates in the thermal.
These are compounds containing a nonaromatic closed ring of carbon atoms in which at least 2 atoms are connected by a double bond. The objective of this experiment was to crack dicyclopentadiene into two molecules of cyclopentadiene and mix cyclopentadiene with maleic anhydride to synthesize cisnorbornene5,6endodicarboxylic anhydride. Modern highpressure thermal cracking operates at absolute pressures of about 7,000 kpa. Because of its reactivity, cyclopentadiene is normally available only in the stable dimer form. Alternatively, thermal decomposition of dcpd or larger oligomers to cyclopentadiene cpd by a retrodielsalder reaction could also explain the observed phenomenon, although unlikely at room temperature.
The kinetics of the thermal degradation of cyclopentadiene in the gas phase were studied by means of a tubular flow reactor with continuous feed of reactant. It was shown that thermal cracking of cyclopentadiene and its methyl derivatives, in fact, yield pyrograms similar to those of the phenolic parent compounds. 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. Two classic metallocene complexes are ferrocene and cobaltocene. 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. Cyclopentadiene is an organic compound with the formula c 5 h 6. The pure cyclopentadiene was obtained by cracking the dimer. Introducing complex nmr mixtures at the undergraduate. Explain why the product distributions of thermal and catalytic cracking.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. In this case, cracking means heating the dimer until it undergoes a retrodielsalder reaction. Dicyclopentadiene is coproduced in large quantities in the steam cracking of. 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. The thermal degradation of phenol and some methylphenols was followed by pyrolysis gas chromatography. Both contain two cyclopentadienyl rings that sandwich a central metal site to give an overall neutral complex co a. Sep 14, 2001 the dimerization is highly exothermic. Explodes on contact with fuming nitric acid or a mixture of sulfuric acid and nitrogen tetroxide. The cyclopentadiene cpd molecules, from which dcpd products are made, originate from high temperature cracking of petroleum fractions in an ethylene manufacturing process. At the end of the experiment, we obtain the desired crystal of cisnorbornene5,6endodicarboxylic anhydride. Characterization of the proteins from vigna unguiculata seeds. Cyclopentadienemaleimide platform for thermally reversible. At room temperature, it is a clear light yellow color liquid with an acrid odor.
Pure cpd can be produced in situ by the thermal cracking of the dcpd at a temperature near the normal boiling point of the dcpd. Cyclopentadiene and dicyclopentadiene cheung major. Cyclopentadiene maleimide platform for thermally reversible polymers jeremy brent stegall abstract this dissertation describes a new platform for the synthesis of thermally reversible polymers, based on dielsalder reactions of biscyclopentadienes biscpds and bismaleimides bismis, that meets two main objectives. Type part of your institution name for a list of matches. H nmr of the mixture of methylcyclopentadiene isomers, zoomed in on the areas of interest. To aid in product isolation, the entire reaction will. Because it start distilling at a temperature 4042 c and before reaching this temperature it cant be distilled. The rate of dimerization at room temperature or below is sufficiently slow to permit participation in a wide range of other reactions. Us patent for process for the vaporphase thermal cracking of. It is usually in the form of polymer because its monomer is easy.
Further, a process for manufacturing high purity dcpd suitable as a raw material for use in rim utilizing the vaporphase thermal cracking process just mentioned above is also described. This invention relates to the thermal decomposition of dicyclopentadiene, c. Cyclopentadiene is obtained by thermal cracking of the dimer and is normally prepared directly before use. Cyclopentadiene is a colorless liquid with an irritating, terpenelike odor. Procedure for preparing cyclopentadiene from its dimer.
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. I recently did a distillation of dicyclopentadiene bp 166 c to get cyclopentadiene bp 40 c. Dicyclopentadiene dcpd was vaporized together with water at a low temperature by using the method of azeotrope formation. The process of producing highpurity cyclopentadiene cpd has been investigated, including a gas phase thermal cracking process of. Various dicyclopentadiene cracking methods are known. Cyclopentadiene belongs to the class of organic compounds known as cycloalkenes. An important step in the thermolysis is the decarbonylation of the phenols yielding cyclopentadienic compds. Cooling to low temperatures slows down this reaction considerably and hence the requirement for cooling immediately after it has been formed by thermal cracking. In the thermal cracking process, the compound to be cracked is subjected to high heat and pressure. Unimolecular thermal decomposition of phenol and d5phenol.
Prediction of heat of formation for exo dicyclopentadiene. Effects of the cracking temperature and residence time on dcpd cracking rate and cpd yield were investigated. As with cyclopentadiene, methylcyclopentadiene is prepared by thermal cracking of its dielsalder dimer, followed by distillation for removal of cyclopentadiene, a common impurity. Us patent for dicyclopentadiene cracking process patent. 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. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a dielsalder reaction. Factors including cracking temperature, reaction time, and h 2 to dcpd ratios were studied. An overall process of disproportionation can be observed, where light, hydrogenrich products are formed at the expense of heavier molecules which condense and. Thermal cracking of dielsalder adducts powers donald h. Experimental procedure part a cracking of dicyclopentadiene. Factors including cracking temperature, reaction time, and h 2 to. Process for producing cyclopentadiene and its homologues. The setup as instructed by my supervisor consisted of a simple watercooled liebig condenser.
The vapor decomposes violently at higher temperatures and pressures. Thermal properties of ruthenium alkylidenepolymerized. C can be obtained addition of iron powder expedites the thermal decomposition rate of cyclopentadiene. This dimer can be restored by heating to give the monomer the compound is mainly used for the production of cyclopentene and its derivatives. They are obtained from coal tar about 1020 gtonne and by steam cracking of naphtha about 14 kgtonne. This colorless liquid has a strong and unpleasant odor. Experiment 14 the dielsalder cycloaddition reaction pg. Pure cpd cyclopentadiene is separated from the crude dcpd by distillation and is redimerized in controlled conditions to avoid oligomer formation. If your institution is not listed, please contact your librarian. Reacts vigorously on contact with potassium hydroxide and other strong bases. Dcpd products from dow can best be characterized as highly reactive intermediates used for a wide range of resins, i. Cyclopentadiene is made by thermal cracking of its dimer, and on standing it slowly reverts to this species. The dissociation to the monomer is a monomolecular reaction. Unreacted cpd is stripped from the highpurity dcpd by mild fractionation.
Stronger heating breaks down polycyclopentadiene and regenerates the monomeric cyclopentadiene as a vapor. Highpurity dcpd in the range of 9899% is produced by thermal cracking of the lowerpurity dcpd. 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. Here, water vapor was introduced into the process of the vaporphase thermal cracking of dcpd as the diluting agent. Heating is applied slowly, because rapid temperature increases cause dicyclopentadiene to distill prior to undergoing thermal decomposition. Dicyclopentadiene, abbreviated dcpd, is a chemical compound with formula c 10h12.
The dicyclopentadiene is added at a rate sufficient to maintain a continuous. Jun 12, 2012 cyclopentadiene undergoes dielsalder reaction to itself to form dicyclopentadiene dimer and also small amounts of polymer. Cracking of dicyclopentadiene chemistry stack exchange. Dcpd is a common byproduct in the naphtha cracking process. Thermal cracking of cyclopentadiene and its me deriv. Mar 02, 2009 thermal decomposition begins at about 150. An important step in the thermolysis turns out to be the decarbonylation of the phenols yielding cyclopentadienic compounds. The thermal degradation of phenol and some methylphenols was followed by pyrolysis gas chromatog. The process of producing highpurity cyclopentadiene cpd has been investigated, including a gas phase thermal cracking process of dicyclopentadiene.
Gas phase cracking of dicyclopentadiene to produce. Barney, abstractnote the pyrolyses of phenol and dsub 5phenol csub 6hsub 5oh. A vaporphase thermal cracking process for resolving the problem by a very simple procedure is described herein. Cyclopentadiene is incompatible with strong oxidizing agents. Why is it important to store the cyclopentadiene below 50c. Heating is applied slowly, because rapid temperature increases. When heated to 180200 c, cyclopentadiene gives polycyclopentadiene, a white waxy solid. 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 gree. The major products were methane, ethylene, propylene, cyclopentene, cyclopentadiene, benzene and toluene. Catalytic enantioselective 1,4iodofunctionalizations of conjugated dienes. Field of the invention 0002 this invention relates to thermal cracking of dielsalder adducts to form a thermally cracked cracked product that contains at least the original compounds from which the adducts were formed, and recovering at least one of the thus formed original compounds from the cracked product. Phase thermal cracking of dicyclopentadiene is in the cyclopentadiene according to the invention can be used as primary source material dcpd from cracking oil, clean or with the content of thi about 10 wt.
This invention relates to the thermal depolymerization or cracking of dicyclopentadiene and its homologues. Cyclopentadiene, which will be used in this experiment cannot be purchased commercially, and must be prepare in the lab by thermally cracking dicyclopentadiene. Us patent for process for the vaporphase thermal cracking. At its simplest, this dimerisation can be described as a. Preparation of cyclopentadiene from its dimer journal of. Possible cyclopentadiene derivatives observed during the thermal cracking of the methylcyclopentadiene dimer. The preexponential factor, activation energy and overall reaction order for thermal cracking of jp10 were determined by nonlinear regression analysis to be 2. Cyclopentadiene is an organic compound with the formula c5h6. Cracking of dicyclopentadiene before the beginning of lab the cyclopentadiene was prepared by a lab technician by cracking it. The apparatus for the cracking of dicyclopentadiene to cyclopentadiene will be set up. Cyclopentadiene undergoes dielsalder reaction to itself to form dicyclopentadiene dimer and also small amounts of polymer. When pure cyclopentadiene is stored it also undergoes a dielsalder cycloaddition reaction and forms. 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. It is soluble in ethyl ether, ethyl alcohol and benzene while insoluble in water.
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