Oxycyanation

This process does produce HCN as a by-product in small quantities. Puranik et al. (1990) report on work to develop an improved, more selective catalyst, and on coupling the ammoxidation process with a second reactor in which a subsequent oxycyanation reaction would convert the by-product HCN to acrylonitrile. 

The similarities and differences between copper-catalyzed oxycyanation and diacetoxy-lation (vide supra), which are summarized in Figure 3, have been discussed. The main difference in the regiochemistry of the two reactions, i.e. an almost exclusive 1,4-addition in the cyanation and a non-regioselective acetoxylation, has been emphasized but was not interpreted in mechanistic terms. 

Hydrides on the palladium are continually removed as water by oxygen present no redox component is necessary. However, other oxidizing components were included in heterogeneous catalysts for the uncommercialized oxidation (Pd-phosphomolybdate) and oxycyanation (olefin/HCN/02 over Pd-vanadia) of ethylene to acetaldehyde (ethanal)/acetic (ethanoic) acid and acrylonitrile (propenonitrile) respectively. 

A direct halogen transfer and solvolysis mechanism has been put forward for the liquid phase oxycyanation of butadiene to 1,4-dicyano-but-2-ene by the system copper-iodine—HCN—air. 

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