Homogeneous side reactions

In a further step, an extended kinetic model was developed and applied, considering the kinetics of the homogeneous side reactions as well [94]. By this means, the activation energies of these processes could be derived. 

In packed-bed reactors, the catalyst is fully wetted, whereas the heat and mass transfer efficiency is higher than that observed in trickle-bed reactors. However, low operation efficiency may appear due to backmixing of the liquid phase. Moreover, high liquid-phase residence times can result in the occurrence of homogeneous side reactions. 

Low liquid-solid volume ratio and hence less occurrence of homogeneous side reactions. 

In the last step, a reactor model was developed taking into account of both the mass transfer of organic components between the two phases and the homogeneous reaction within the aqueous phase, the latter relying on literature data [22], From there, an extended kinetic model was developed and applied, considering the kinetics of the homogeneous side reactions as well [22], With these efforts, the activation energies of these processes could be derived. 

Liquid-to-solid ratio is small, minimizing the homogeneous side reactions if possible. 

The high ratio of liquid to solid may allow homogeneous side reactions to become important, if they are possible. 

Homogeneous side reactions Residence time distribution Pressure drop Temperature control Heat recovery Catalyst handling Catalyst consumption Maximiam volume Maximum working pressure Process flexibility Investment costs Operating costs Reactor design and extra-... 

Selectivity, which is one of the most important characteristics of an industrial process, depends on several parameters temperature control, residence time distribution, gas and liquid hold-ups, catalyst loading, catalyst type, mass transfer rates etc... If homogeneous side reactions are awkward, fixed beds give better results.But if the desired product can react further on the catalyst, small catalyst particles have to be preferred to avoid concentration gradients in the pores and slurry reactors are the best. In this last case, the poor residence time distri-... 

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