Ammoxidation allyl alcohol

The surface transformations of propylene, allyl alcohol and acrylic acid in the presence or absence of NHs over V-antimonate catalysts were studied by IR spectroscopy. The results show the existence of various possible pathways of surface transformation in the mechanism of propane ammoxidation, depending on the reaction condition and the surface coverage with chemisorbed NH3. A surface reaction network is proposed and used to explain the catalytic behavior observed in flow reactor conditions. 

Oxidation of the allylic carbon of alkenes may lead to allylic alcohols and derivatives or a, 3-unsaturated carbonyl compounds. Selenium dioxide is the reagent of choice to carry out the former transformation. In the latter process, which is more difficult to accomplish, Cr(VI) compounds are usually applied. In certain cases, mixture of products of both types of oxidation, as well as isomeric compounds resulting from allylic rearrangement, may be formed. Oxidation of 2-alkenes to the corresponding cc,p-unsaturated carboxylic acids, particularly the oxidation of propylene to acrolein and acrylic acid, as well as ammoxidation to acrylonitrile, has commercial importance (see Sections 9.5.2 and 9.5.3). 

Ammoxidation of allyl alcohol on MOO3 initially requires about 6 molecules of NH3 per allyl alcohol in the vapor phase for maximum acrylonitrile yield (Fig. 15). However, after all surface Mo=O undergo ammonolysis to form Mo=NH, only a stoichiometric (or slightly higher) amount of ammonia is required to sustain maximum AN yield under catalytic conditions. These results suggest that N incorporation results from an O to N-allylic rearrangement (Scheme 10) (27). 

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