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The process, which is catalyzed by platinum supported by aluminium oxide, is exemplified in the conversion methylcyclohexane (a naphthene) into toluene (an aromatic). [2] Dehydrocyclization converts paraffins (acyclic hydrocarbons) into aromatics. [3] A related aromatization process includes dehydroisomerization of methylcyclopentane to benzene:
The spontaneous dimerization of neat cyclopentadiene at room temperature to form dicyclopentadiene proceeds to around 50% conversion over 24 hours and yields the endo isomer in better than 99:1 ratio as the kinetically favored product (about 150:1 endo:exo at 80 °C). [6] However, prolonged heating results in isomerization to the exo isomer.
Cyclopentadiene is a highly reactive diene in the Diels–Alder reaction because minimal distortion of the diene is required to achieve the envelope geometry of the transition state compared to other dienes. [11] Famously, cyclopentadiene dimerizes. The conversion occurs in hours at room temperature, but the monomer can be stored for days at ...
1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene is an organochemical compound from the diene group and a cyclopentadiene derivative. The anion of this compound is used as a sterically demanding ligand, often abbreviated as Cp [BIG] , in the organometallic chemistry of sandwich compounds .
The reaction of cyclopentadiene and butenone for example is 700 times faster in water relative to 2,2,4-trimethylpentane as solvent. [14] Several explanations for this effect have been proposed, such as an increase in effective concentration due to hydrophobic packing [ 15 ] or hydrogen-bond stabilization of the transition state.
Cp 2 Fe 2 (CO) 4 was first prepared in 1955 at Harvard by Geoffrey Wilkinson using the same method employed today: the reaction of iron pentacarbonyl and dicyclopentadiene. [7] [8] 2 Fe(CO) 5 + C 10 H 12 → (η 5-C 5 H 5) 2 Fe 2 (CO) 4 + 6 CO + H 2. In this preparation, dicyclopentadiene cracks to give cyclopentadiene, which reacts with Fe(CO ...
In 2011, Jordi Poater and Miquel Solà expanded the rule to open-shell spherical compounds, finding they were aromatic when they had 2n 2 + 2n + 1 π-electrons, with spin S = (n + 1/2) - corresponding to a half-filled last energy level with the same spin. For instance C 60 1– is also observed to be aromatic with a spin of 11/2. [16]
The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer , when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I ...