Selective Oxidation Catalysts at Clariant

The chapter presents a brief overview of the current research on V205/Ti02 catalysts for o-xylene oxidation to phthalic anhydride at Clariant. Phthalic anhydride is produced in tubular, salt-cooled reactors with a capacity of about 5 Mio to per annum. There is a rather broad variety of different process conditions realized in industry in terms of feed composition, air flow rate, as well as reactor dimensions which the phthalic anhydride catalyst portfolio has to match. Catalyst active mass compositions have been optimized at Clariant for these differently realized industry processes utilizing artificial neural networks trained on high-throughput data. Fundamental pilot reactor research unravelling new details of the reaction network of the o-xylene oxidation led to an improved kinetic reactor model which allowed further optimizing of the state of the art multi-layer catalyst system for maximum phthalic anhydride yields. 

As one of the world s leading specialty chemical companies, Clariant contributes to value creation with innovative and sustainable solutions for customers from many industries. The business units are divided into four Business Areas Care Chemicals, Catalysis Energy, Natural Resources and Plastics Coatings. The product portfolio of Clariant provides competitive and innovative solutions to customers and research and development is focused on addressing the key trends of our time. These include energy efficiency, renewable raw materials, emission-free mobility and conserving finite resources. 

Clariant s Catalysts business unit has its roots in the Sud-Chemie company which was founded by Justus von Liebig in Upper Bavaria close to Munich. This unit has a history stretching back over more than 150 years. Siid-Chemie s catalyst activities were established in 1962. Fifty years on, it is the world s leading manufacturer 

A little more than a decade ago, Clariant decided to venture into the field of partial oxidation reactions. Catalysts for selective partial oxidation reactions thus belong to the most recent developments in the catalyst portfolio of Clariant. The portfolio of oxidation catalysts currently comprises SulfoMax for sulfuric acid production, FAMAX for formaldehyde production, PHTHALIMAX for phthalic anhydride production, SynDane for maleic anhydride production, and most recently VAM ax for vinyl acetate production. 

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Recently the PHTHALIMAX family has been extended by a special catalyst for adiabatic post-reactor application, PHTHALIMAX -F. This catalyst is designed to operate at rather low temperatures and with a high selectivity to convert under oxidation intermediates to PA and over-oxidation intermediates to COx without combusting PA. One of the pilot units is equipped with an adiabatic post-reactor which is used for the development of this class of catalysts. The use of an adiabatic post-reactor with the correct operation of the Clariant post-catalyst can increase the overall plant PA yield by 1 wt%. 

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