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Dicyclopentadiene decomposition

To determine how long the sulfur formulation could be held in a molten state before spraying, its stability was measured on holding at 135 and 180 °C. Stability was indicated by the hardness and impact strength of solidified samples taken at timed intervals. Molten formulation held at 135 °C for over 2 months did not deteriorate. At 180 °C, decomposition was noted after 30 days, and the material solidified into a black, friable mass after 45 days. This was attributed to carbonization of the mixture by dicyclopentadiene decomposition. [Pg.71]

The reaction of starmylated dicyclopentadiene (111) with methyllithium gave dicyclopentadiene (113) and cyclopentadienyllithium (114) even at -78 C." The intermediate can be trapped by addition of iron(II) cMoride to give intermediate (115), which then cleaves off cyclopentadiene m one of the two dicyclopentadiene ligands in a rDA process to give (116) as the isolated product. It therefore appears that the rDA decomposition is only partially blocked by trapping with iron(II) chloride. [Pg.568]

Even though the second double bond provides some stabilization, resistance of the compounds to decomposition by Pd(II)-assisted hydride transfer is interesting. Thus, Pd (II) alkyls with -hydrogens even when they have phosphine groups (which would be expected to be better than olefin groups in stabilizing Pd(II) alkyls) decompose rapidly. As recently discussed by Stille and Morgan (39), the stability of the adducts from bicyclic olefins such as the one from dicyclopentadiene (Reaction 72) can probably be reasonably attributed to the fact that Pd( II)-hydride elimination would form a strained double bond. However, the stability of the adduct from 1,5-cyclooctadiene cannot be explained in this way. [Pg.151]

Another example of the retention of volatile DA reagents is that of cyclopentadiene in a tandem retro-DA-DE prime reaction [15, 38]. This reaction type is the thermal decomposition of a DA adduct (A) and the generation of a diene (generally the initial diene) which is trapped in situ by a dienophile leading to a new adduct (B) [39]. Cyclopentadiene (22) (b.p. 42 °C) is generated by thermolysis of its dimer at approximately 160 °C [40]. An equimolar mixture of commercial crude dicyclopentadiene (21) and dimethyl maleate was irradiated in accordance with the GS-MW process, in an open reactor, under 60 W incident power, for 4 min... [Pg.421]

In an attempt to reach an isomeric [5.5.5.5]fenestrane, Luyten and Keese prepared the epimeric ketolactone 82 from dicyclopentadiene. Here decomposition of the tosylhydrazone salt led only to olefin 83. Once again the high-temperature palladium and hydrogen process was effective, but the product was 78 rather than the desired (la,4a,7a,10)5)-[5.5.5.5]fenestrane According to molecular mechanics calculations this latter unknown isomer should be about 13 kcal mol more strained than 78 . [Pg.940]

Dicyclopentadiene has two cyclopentene rings with different reactivities. In the reaction with nickel complexes and carbon dioxide only the more reactive norbornene ring couples with CO2, whereas the unstrained ring proved to be unreactive [14,16]. The last example in Figure 6 is cyclooctatetraene, which stands in a temperature-dependent equilibrium with bicyclo[4.2.0]octatriene. Both isomers undergo an oxidative coupling with nickel and CO2. Decomposition by hydrochloric acid leads to cycloocta-2,4,6-triene-carboxylic acid and bicyclo-[4.2.0]octa-2,4-diene-7-carboxylic acid [14]. [Pg.65]

This procedure must be carried out in a fume cupboard. Assemble the apparatus shown in Figure 1.7, and perform the reaction under an atmosphere of dry nitrogen. Add Fe(CO)5 (14.6 g, 10 ml 70.5 mmol) and dicyclopentadiene (60 g, 64 ml 455 mmol) to the flask. Reduce the nitrogen flow and heat the reaction mixture under reflux to 135 °C for 8 to 10 hours. (It is important not to let the temperature go below 130 °C (as no reaction will occur) or above 140 °C (decomposition of the product will occur). After the reaction period, allow the mixture to cool slowly to room temperature. ... [Pg.19]


See other pages where Dicyclopentadiene decomposition is mentioned: [Pg.378]    [Pg.709]    [Pg.1587]    [Pg.378]    [Pg.100]    [Pg.1653]    [Pg.1587]    [Pg.405]    [Pg.100]    [Pg.3210]    [Pg.1587]    [Pg.177]    [Pg.472]    [Pg.405]    [Pg.355]    [Pg.3209]    [Pg.455]    [Pg.501]   
See also in sourсe #XX -- [ Pg.109 ]




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