CATALYSIS AND PROCESS DEVELOPMENT

 

This research group is mainly concerned with the application of multiphase catalysis to the synthesis of organic chemical intermediates for the pharmaceutical, fragrance and agrochemical industries. Processes are being developed using unit syntheses such as halogenation, hydrogenation, oxidation, alkylation and carbonylation in heterogeneous systems. Major contributions were made in the field of phase transfer catalysis, where concurrent extraction and reaction were performed in the presence of amphiphilic multifunctional catalysts. Simple reagents such as hydrogen peroxide, tert-butyl hydroperoxide, hypochlorite, phosphate, bicarbonate, sulfide, halides and isocyanate were reacted with various organic substrates under mild conditions to yield various functional products.

Recent novel synthetic routes which were developed by the group include:

• Liquid phase selective phase transfer catalyzed auto-oxidation of substituted toluenes to benzoic acids or benzaldehydes.

• A unique new catalytic system for the Halex reaction-exchange of activated aryl halides with potassium fluoride or potassium bifluoride, to yield the corresponding aryl fluorides.

• A liquid-liquid catalytic process for the hypochlorite oxidation of substituted naphthalene to yield specific functional phthalic acids or anhydrides.

• Syntheses of small ring systems (cyclopropanes and cyclobutanes) via an intra-molecular phase transfer alkylation process of ?-chloro nitriles, esters or ketones.

• A novel process for syntheses of biaryls via catalytic reductive coupling of aryl halides, has been developed.