HPPO process

Fig. 14 Hydrogen peroxide to propylene oxide (HPPO) process...

Together with the engineering company Uhde (Germany), Degussa (now Evonik Industries) has also developed an innovative process for producing propene oxide (PO) from H202, the so-called HPPO process. The Korean company SKC, Seoul, has... 

Degussa, in turn, has recently announced the commercialization of a HPPO process, jointly developed with the engineering company Uhde. Parallel to this, Degussa with Headwaters is also working on the direct synthesis of H2O2, for which a demonstration plant was completed in 2006 [151]. According to the news release, hydrogen peroxide will be obtained in the new process as a dilute methanol solution to be used directly in the epoxidation of propene. 

The catalyzed reaction of the elements produces hydrogen peroxide directly, in competihon with water (Equation 18.16). Most selective catalysts are based on supported Pd, often modified by other metals. Methanol is increasingly studied as a reachon medium, from the perspective of the direct use of the solution obtained in the HPPO process. For high selectivihes, the reaction normally necessitates relatively low temperatures, often room temperature or lower, and the presence of mineral acids and other additives [153]. 

HPPO Processes HP Generation by Redox Cycles on Organic O Carriers... 

Joint ventures and collaborations for the implementation of newly developed HPPO processes have been established between BASF, Dow and Solvay, and between Degussa-Evonik, Headwaters and Krupp-Uhde [11]. 

From the Dream Reaction to the Real Process the Implemented HPPO Process... 

HPPO and In Situ HPPO Processes HP Generation by Direct Oxidation of H2 (DSHP)... 

Still several problems remain unsolved to make the DSHP-HPPO process economically viable (i) safety the reaction of H2 with O2 in the presence of a flammable solvent (methanol) puts high hurdles on safety (ii) removal of acid and bromide the Bronsted acid and the bromide needed to produce HP from the elements have to be removed before the generated H P solution can be used for epoxidation (iii) solvent recycle after the generated H P solution has been used for epoxidation, the methanol has to be separated and recycled. During work-up some additional by-products are formed formaldehyde, acetaldehyde, propionaldehyde, methyl formate, dimethoxymethane, 1,1-dimethoxyethane and 1,1-dimethoxypro-pane. These compounds are difflcult to separate (many make azeotropes with methanol), so the recovered methanol will be contaminated. However, even small amounts of aldehydes or formates can poison the Pd or Pd/Au catalyst. Additional equipment needed to solve these problems will increase the investment costs. 

Scheme 14.2 HPPO process for the synthesis of propylene oxide.

A joint BASF/Dow HPPO plant (300 000 ta PO) was constructed in Antwerp in 2006, partnerii with Solvay as a supplier of H Oj (230000ta H O ). Evonik (formerly Degussa) developed an HPPO process with Uhde, opening a plant in Ulsan, South Korea (100 000 ta PO), licensed to SKC in 2008. And finally, an HPPO plant operated by Dow/SCG began production in Thailand in 2011 (390 000 ta PO) with a companion H O plant (330 000 ta ) nearby. 

Figure 1.13 Simplified process flow diagram for propylene oxide production via oxidation of propylene catalyzed by TS-1 with H2O2 as the oxidizing agent (Dow-BASF HPPO process). Adapted from US 7,138,534.

Compared with conventional PO process technologies, the HPPO process offers unique benefits in three areas economics, protection of the environment, and opportunities for future growth. 

In 2008, BASF and Dow Chemical successfully started the first commercial production plant based on the novel hydrogen peroxide to propylene oxide (HPPO) process. The plant is located in Antwerp, Belgium and the initial annual capacity is around 300 000 tons. A second plant based on this technology will start production in 2011 in Map Ta Phut, Thailand. 

Evonik and Uhde have also developed a HPPO process, which was commercialized in 2008 in Ulsan, South Korea (100 000 t a ). The indirect oxidation takes place at increased pressure and temperatures below 100 °C with the solvent methanol. The reaction is catalyzed by a titanium-silicate catalyst in a solid-bed reactor that is special due to its p,-reactor characteristic in one dimension. Using this new reactor type it is possible to improve isothermicity and to avoid disadvantageous concentration profiles. Figure 6.12.7 shows the pilot plant reactor of this new propylene oxidation process. Yields of 95% (relating to propylene) and 90% (relating to H2O2) are obtained in the Evonik/Uhde process. 

Since summer 2008, the South Korean company SKC has been producing propene oxide in Ulsan using the innovative HPPO process developed by Evonik/Uhde. The HPPO facility has a capacity of 100,000 metric... 

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