Single-Stage Acetaldehyde Process from Ethylene

Single-Stage Acetaldehyde Process from Ethylene 

The single-stage process was developed by a research group of Hoechst AG (also see [36]). At the time, Hoechst AG owned 50% of the shares of Wacker Chemie. Via the board, they learned at an early time about Wacker s activity on ethylene oxidation and began research on this field. Later on, both companies cooperated and combined their results. 

The purification (h) and regeneration (i) steps have the same function as the analogous steps in the two-stage process described in the following section. 

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Single-Stage Acetaldehyde Process from Ethylene... 

Figure 2. Acetaldehyde from ethylene, single-stage process (a) reactor, (b) separating vessel, (c) cooler, (d) scrubber, (e) crude aldehyde tank, (f) light ends distillation,...

Acetaldehyde may be prepared from ethylene via the Wacker process, and then oxidized as above. In more recent times, a cheaper, single-stage conversion of ethylene to acetic acid was commercialized by chemical company Showa Denko, which opened an ethylene oxidation plant in Oita, Japan, in 1997. The process is catalysed by a palladium metal catalyst supported on a heteropoly acid such as tungstosilicic acid. It is thought to be competitive with methanol carbonylation for smaller plants (100-250 kt/a), depending on the local price of ethylene. 

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