MULTIPHASE CATALYTIC REACTOR ENGINEERING AND DESIGN FOR PHARMACEUTICALS AND FINE CHEMICALS

A review of recent developments in multiphase catalytic processes for the manufacture of pharmaceutical and fine chemicals, and an overview of reaction engineering principles needed for analysis of the local an d overall reaction rate for reactor design and interpretation of perfo rmance is presented. The first section gives an overview of recent app lications in pharmaceuticals and fine chemicals where heterogeneous an d homogeneous catalyzed multiphase chemistries have been identified th at are more efficient and represent safer operation with decreased env ironmental impact when compared to existing processes. The next three sections describe a scheme for classification of the Various types of reactions that are typically encountered, along with distinguishing fe atures of these reactions and commonly used multiphase reactor types. This is followed by a review of reaction engineering principles needed for describing the local overall rate of reaction, including a summar y of typical models for evaluation of the intrinsic reaction kinetics, incorporation of transport-kinetic interactions, methods for identifi cation of the controlling reaction regime and assessment of the relati ve contribution of transport effects. The next two sections set forth basic reactor models for commonly used reactor types, including mechan ically agitated reactors and bubble column reactors. A brief summary o f commonly used correlations for estimation of mass transfer coefficie nts in these reactors for gas-liquid and liquid-liquid systems is also even. The final section is devoted to a summary of key reaction engin eering issues that occur in pharmaceutical and fine chemical multiphas e catalytic processes, along with some thoughts on future needs and ch allenges.