Chementator: A commercial debut for a process to make propylene oxide
By Chemical Engineering |
At last month’s Achema conference (Frankfurt; May 15–19), Norbert Ullrich, chief engineer at Uhde GmbH (Dortmund, Germany; edlinks.chemengonline.com/5830-533) announced a first customer for and presented details about a new hydrogen-peroxide-based propylene oxide (HPPO) process, developed by Degussa AG (Düsseldorf, Germany; edlinks.chemengonline.com/5830-534) and Uhde (CE, February 2001, p. 17). The process is expected to be more economical than alternative routes and it produces no side products or chlorine-laden waste. Currently, around 50% of the PO is manufactured by the classic chlorohydrin process and the other 50% using two organic hydroperoxide processes. These processes all generate a large amount of coproduct along with the product PO.
With the HPPO process (flowsheet), propylene is catalytically oxidized with H2O2 to PO and H2O. The exothermic reaction takes place in a methanol solvent over a solid titanium silicalite catalyst, which was optimized by Degussa with respect to hardness and high selectivity. The PO reactor operates at elevated pressure (high enough to keep the reagents in the liquid phase) and temperatures below 100°C. The key to the process is the tubular epoxidation reactor; its innovative…