Influence of supercritical fluid solvent density on benzyl phenyl ether pyrolysis: indications of diffusional limitations

Abstract

The influence of supercritical solvent density on the pyrolysis of benzyl phenyl ether (BPE) in tetralin and supercritical toluene is interpreted in terms of transport limitations. Reaction at varying toluene densities highlighted the transport dependence of the BPE fission rate constant. The conversion of BPE decreased from 0.55 to 0.15 as the toluene density increased from 0.0 to 0.75. The yield and selectivity of BPE rearrangement products were also density dependent. These results were explained and modeled quantitatively in terms of the cage effect theory.

Reactions at supercritical conditions: Applications and fundamentals

“…Contributions for the latter three effects were evaluated. These investigators also examined the influence of density on reactions in SCFs ( Wu et al, 1991~). They showed that the conversion of benzyl phenyl ether decreased with increasing solvent (toluene) density, as shown in Figure 2'7.…”

Towards Quantitative Catalytic Lignin Depolymerization

“…This effect is predominantly observed in supercritical water, but has been invoked for reactions in subcritical water to rationalize the change in reaction pathways with different solvents or with increasing water density. [28] In the same way oligomer formation could potentially be suppressed, as the solvent cage would hinder diffusion of the sodium phenolate ion pair and thus suppresses formation of a carbanion.…”

Catalytic Cleavage of Ether Bond in a Lignin Model Compound over Carbon-Supported Noble Metal Catalysts in Supercritical Ethanol

“…Hence, the reaction of a model compound containing α-O-4 bond can be of fundamental importance in understanding selective cleavage of ether bonds. In this respect, benzyl phenyl ether (BPE), which has an ether bond similar to α-O-4 bond without other functional groups, can be the simplest model to indirectly predict α-O-4 bond cleavage [15,[17][18][19].…”