ABSTRACT
Homogeneous catalysis by soluble transition metal complexes offers many advantages over heterogeneous catalysis, such as milder reaction conditions, higher activities and selectivities, and better control of operating conditions. Such superior performance arises from the ability of transition metals to complex with a wide variety of ligands in a number of geometries and to easily change from one oxidation state to another. Even though heterogeneous catalysts dominate the industrial scene today (about 85% of all existing catalytic processes), the importance and market share of homogeneous catalysts are growing at a very fast pace. This growth is being fueled by a combination of factors:
1. Environmental and economic pressures for cleaner processes 2. Growth in specialty and fine chemicals 3. Scientific advances in organometallic chemistry
and is expected to continue in the coming decade. A list of some of the chemicals that are manufactured using homogeneous catalysts is given in Table 1 (1-3).
