Cyclopentane

Abstract: Laminar flame speeds determined by using the counterflow twin flame configuration were compared for various C1 to C8 hydrocarbons, including alkanes, alkenes, alkynes, aromatics, and alcohols. The data were compared over an extensive range of equivalence ratios at room temperature and atmospheric pressure. The comparison shows that the laminar flame speeds of normal alkanes are close throughout the entire range of equivalence ratios studied, except for methane whose flame speeds are consistently lower. The more unsaturated the molecule the higher the flame speed for fuels having the same carbon number in the order of alkanes < alkenes < alkynes. Methyl substitution for hydrogen or branching reduces the flame speeds for both alkanes and alkenes. The flame speeds of large saturated cyclic species (cyclohexane and cyclopentane) are close to those of their normal alkane analogs.

Abstract: Publisher Summary The skeletal rearrangements of hydrocarbons represent an important class of reactions catalyzed by metal surfaces, that have few counterparts in homogeneous catalysis. The first examples of skeletal rearrangements on metals were reported by the Soviet school of catalysis. A major step in hydrocarbon chemistry is the finding that platinum, unlike palladium and nickel, selectively catalyzes the hydrogenolysis of cyclopentane hydrocarbons. At about 300°C, on the classical Zelinskii platinum-charcoal catalyst, cyclopentane yields n -pentane as sole reaction product, while palladized charcoal is completely inactive and nickel-alumina produces all the possible acyclic hydrocarbons, from methane to pentane. The predominant precursor species in skeletal rearrangements are metallocyclobutanes and metallocarbenes, which can be further dehydrogenated to metallocarbynes, dicarbenes, or carbene-olefin complexes, and react like the analogous species in coordination chemistry. Metallocyclobutane dismutation and the reverse reaction, carbene-olefin addition, are the two major steps in olefin metathesis, and dicarbene recombination also has an analogue in organometallic reactions.

Abstract: The present work uses a micromechanical force apparatus to directly measure cyclopentane clathrate hydrate cohesive force and hydrate-steel adhesive force, as a function of contact time, contact force and temperature. We present a hydrate interparticle force model, which includes capillary and sintering contributions and is based on fundamental interparticle force theories. In this process, we estimate the cyclopentane hydrate tensile strength to be approximately 0.91 MPa. This hydrate interparticle force model also predicts the effect of temperature on hydrate particle cohesion force. Finally, we present the first direct measurements of hydrate cohesive force in the gas phase to be 9.1 ± 2.1 mN/m at approximately 3 °C (as opposed to 4.3 ± 0.4 mN/m in liquid cyclopentane).