Zeolite catalyts have acquired considerable technical and economical importance in refinery technology and petrochemistry. Over the past ten years, the search for applications of zeolite catalysis in the synthesis of organic intermediates and fine chemicals has been stepped up. An important aspect in this development is the changeover of reactions carried out over homogeneous catalysts to heterogeneous zeolite catalysis.
From this range of applications, it is intended to present two selected processes. These are the synthesis of pivalic acid and -caprolactam. The dependence on test parameters and on the catalyst properties such as acidity and doping, is described. A comparison is made with the conventional process carried out industrially. The advantages and disadvantages of the zeolite-catalyzed process are weighed up against one another.
The production of ε-caprolactam and pivalic acid by heterogeneous catalysis over zeolite catalysts offers a genuine alternative to the industrial processes employing homogeneous catalysis, particularly from the point of view of environmental protection, since the use of toxic BF3 and NH2OH as well as the inevitable coproduction of ammonia sulfate is avoided.