Cativa process
From Wikipedia, the free encyclopedia
![Space-filling model of the [Ir(CO)2I2]− catalyst used in the Cativa process](../../../../images/shared/thumb/5/53/Dicarbonyldiiodoiridium(I)-3D-vdW.png/200px-Dicarbonyldiiodoiridium(I)-3D-vdW.png)
The Cativa process is a route to the manufacture of acetic acid. It is similar to the rhodium based Monsanto process. The Cativa technology was developed by BP Chemicals Ltd and is the forefront of acetic acid production. The Cativa process is under license BP Plc [1] [2] .
In the Cativa process the active catalyst is based on iridium; [Ir(CO)2I2]−.
Due to similar chemistry to the Monsanto process the same chemical plant may be used. Initial studies by Monsanto had shown the iridium complex to be a less active catalyst than the rhodium complex. However subsequent research showed that the iridium catalyst could be promoted using ruthenium, and this combination leads to a more active and more specific catalyst than the rhodium compound.
The switch from rhodium to the cheaper iridium allows the use of less water in the reaction mixture. This reduces the number of drying columns necessary, decrease by-products formation and suppress the water gas shift reaction. Also, a higher catalyst loading can be used. Compared with the Monsanto process, less propionic acid by-product is produced.
[edit] References
- ^ Jones J. H. (2002). "The CativaTM Process for the Manufacture of Acetic Acid". Platinum Metals Review 44 (3): 94–105.
- ^ Sunley GJ, Watson DJ (2000). "High productivity methanol carbonylation catalysis using iridium - The CativaTM process for the manufacture of acetic acid". Catalysis Today 58 (4): 293–307. doi:.
