Previously, tungsten blue, HW3O9, was used in a variety of catalytic reactions including the conversion of cyclopentene to decalin, hydrolysis of alkynes and nitriles, trans alkylation of aromatics, and trimerization of alkynes. The chemistry of this catalyst is unpredictable since it can act as a superacid, a hydrogenating reagent and a reducing agent. Therefore, in this investigation, catalytic reactions of tungstic acid were investigated with the expectation that H2WO4 would simply behave as a strong acid due to the absence of tungsten(V) ions. However, the interaction of tungstic acid with alkenes and alkynes was found to be complex often with different reactions occurring with small changes of substrate. Hydrogenation, dimerization, cyclotrimerization, oligomerization, and hydration reactions were observed. One completely unexpected result was the conversion of diphenylacetylene to benzaldehyde.   The scope of these reactions, their dependence on temperature and amount of catalyst, and where possible, the sequence of products formed will be discussed.

Chemical transformations of alkene and alkyne using tungstic acid as a catalyst: Kinetics and reactions mechanisms

246th National Meeting (2013)

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