FRANZ SCHMIDT, MAIK BERNHARD, HEIKO MORELL, MATTHIAS PASCALY*
*Corresponding author
Evonik Industries AG, Advanced Intermediates – Innovation, Rodenbacher Chaussee 4, 63457 Hanau-Wolfgang, Germany

Abstract

The common industrial technologies for the conversion of propylene to propylene oxide have been compared with a special focus on the direct oxidation using hydrogen peroxide. The HPPO process is an economically and ecologically superior technology since there are no market dependencies of other coproducts and water is the only waste product. The catalyst used in this process is a partly titanium substituted silica based zeolite called TS-1. The article summarizes the most important information concerning the HPPO process.

INTRODUCTION

The oxidation of organic compounds is of vital importance for the chemical industry. Besides basic oxidation reactions such as bleaching processes (e.g. paper or laundry) also oxidation reactions of chemicals are important: Epoxides - especially ethylene and propylene oxide – are among the major chemicals. Replacement of traditionally used halide-based oxidants (chlorine) by hydrogen peroxide provided a new route to the desired oxidized products. Past demand for hydrogen peroxide was due to the replacement of a chlorine bleaching step in the paper industry or the introduction of percarbonates as bleaching agent in detergents. Today, the newly developed HPPO (hydrogen-peroxide-to-propylene-oxide) process is one of the largest consumers of hydrogen peroxide for the epoxidation of propylene yielding propylene oxide on a titanium doped zeolite without any coproducts. Also in this case, the oxidative potential of hydrogen peroxide allows the replacement of traditionally used chlorine-based oxidants enabling a novel environmentally more benign process.
This article provides an overview on the HPPO technology which is now state of the art ...