MA from C4 Hydrocarbons

The alternate commercially practiced route to MA uses n-butane, butene-1, butene-2, and butadiene or a mixture thereof. The mechanism of the overall process is less well understood. The process is also complicated by the number 

Bisset and Benson,at DuPont, studied the partial oxidation of n-butane using a cobalt molybdate catalyst. The MA formation kinetics suggested that there were two consecutive first-order reactions  

The intermediate oxidations are so rapid that they have no significant influence on the overall kinetics. Ai and coworkers also show that overall oxidation is much faster than isomerization as shown in Fig. 2-8. 

Dehydrogenation of butane to a mixture of butenes given by the rate constant ka is first order in butane and independent of the oxygen concentration. Since higher yields of MA are obtained from c/5-butene-2 than the mixture of cis and trans isomers, the stereochemistry of the butene formation may be important in determining kb vs 

Sampson and Shooter, from their study on vanadium oxide/phos-phorus pentoxide catalyzed oxidation of n-butane, suggest that there are two potential routes of MA one via crotonaldehyde and the other via butadiene. Furan has also been suggested as an intermediate in the sequence. 

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