Hydrogenation cyclohexene

The cyclohexene hydrogenation is a well-studied process especially in conventional trickle-bed reactors (see original citations in [11,12]) and thus serves well as a model reaction. In particular, flow-pattern maps were derived and kinetics were determined. In addition, mass transfer can be analysed quantitatively for new reactor concepts and processing conditions, as overall mass transfer coefficients were determined and energy dissipations are known. In lieu of benchmarking micro-reactor performance to that of conventional equipment such as trickle-bed reactors, such a knowledge base facilitates proper, reliable and detailed comparison. 

Cyclohexene hydrogenation is a fast process so mass transfer limitations are likely [12]. Processing at room temperature and atmospheric pressure reduces the technical expenditure for experiments. 

Intrinsic Selectivity to Benzene During Cyclohexene Hydrogenation- Dehydrogenation is Sensitive to Pt Particle Size... 

Table 6. Cyclohexene hydrogenation-dehydrogenation rates on Pt/SBA-15 nanoparticle encapsulation catalyst series [18].

Figure 15. Turnover rate for cyclohexene hydrogenation and dehydrogenation as a function of particle size. Reaction conditions are lOTorr CeHio, 200 Torr H2, and 310K for hydrogenation and 448 K for dehydrogenation, respectively [18].

Figure 2 Hydrogen uptake curves for cyclohexene hydrogenations ran at 35°C and 50 psig of hydrogen in 10% toluene/EtOH with a stirring rate of 1700 rpm. a) AHC-Wilk catalyst b) Homogeneous Wilkinson s catalyst.

Kinetic data on cyclohexene hydrogenation catalyzed by RhClL species (n = 1, 2, or 3 L = p-dimethylaminophenyl phosphines) were interpreted in terms of active dimer catalysts (cf. 1), possibly involving coordination through nitrogen as well as phosphorus (82). 

This kinetic equation is applied to the observed kinetic curves obtained in cyclohexene hydrogenation (model reaction) following the molecular hydrogen consumption. Of note, the present kinetic equation provides the value of fe2obs and not kj. However, the real value of the rate constant k2 can be obtained easily using the relationship k2 = k2obs x S/C, where S/C is the substrate/catalyst molar ratio (the catalyst is given as the number of metaUic moles employed). 

Cyclohexene hydrogenation is a well-studied process that serves as model reaction to evaluate performance of gas-liquid reactors because it is a fast process causing mass transfer limitations for many reactors [277,278]. Processing at room temperature and atmospheric pressure reduces the technical expenditure for experiments so that the cyclohexene hydrogenation is accepted as a simple and general method for mass transfer evaluation. Flow-pattern maps and kinetics were determined for conventional fixed-bed reactors as well as overall mass transfer coefficients and energy dissipation. In this way, mass transfer can be analyzed quantitatively for new reactor concepts and processing conditions. Besides mass transfer, heat transfer is an issue, as the reaction is exothermic. Hot spot formation should be suppressed as these would decrease selectivity and catalytic activity [277]. 

Hydrogenation Function of Fresh and Deactivated Hydrocracking Catalysts Cyclohexene Hydrogenation... 

A systematic study of the history of the hydrogenation function ip a series of fresh and deactivated commercial hydrocracking catalysts is reported using cyclohexene hydrogenation as a probe reaction. 

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