The Wacker-Smidt Synthesis of Acetaldehyde

Hafner, R. Jira, J. Sedlmeier, R. Sieber, R. Riitlinger, and H. Kojer, Angew. Chem., 1959, 71, 176 and J. Smidt, W. Hafner, R. Jira, R. Sieber, J. Sedlmeier, and S. Sabel, Angew. Chem. Intemat. Edit. Engl., 1962, 1, 80. 

The Wacker-Smidt process—hereafter known simply as the Wacker oxidation, reaction, or process—enjoyed considerable success, yet its use has declined dramatically over the past 10 years for at least two reasons.49 First, manufacturing plants are expensive to build and maintain because they must be constructed to withstand a corrosive environment. Second, another procedure that yields acetic acid directly from synthesis gas was developed and now supplants the Wacker-Smidt process. This newer route also uses homogeneous catalysis involving Rh and Ir complexes and will be described in Section 9-5. 

48For a good discussion of the Wacker-Smidt and related processes, see P. Wiseman, An Introduction to Industrial Organic Chemistry, Wiley New York, 1976, pp. 97-103. A process using palladium-impregnated silica, developed later, is superior to the homogeneously-catalyzed process described in equation 9.17. 

49 Acetaldehyde production via the Wacker process in North America has ceased only China remains as a significant producer of this compound, presumably using, at least in part, the Wacker process (S. M. Malveda, K. Fujita, and B. Suresh, Acetaldehyde, in Chemical Economics Handbook, SRI Consulting Menlo Park, CA, 2007). 

The first major transformation in the pathway probably consists of two steps in which two Cl ions are displaced and substituted with alkene and H20. These set the stage for nucleophilic attack on the bound alkene. 

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Catalytic Cycle of the Wacker-Smidt Synthesis of Acetaldehyde... 

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