Phosphotungstic heteropoly acid, also called Keggin type phosphotungstic acid, belongs to twelve phosphotungstic acid with the formula of H3PW12O40•nH20. It is a light yellow crystal or white powder. Different crystal water content cause difference in color. It is generally light yellow if it contains more crystal water; otherwise, it is white powder. It is soluble in water, alcohol, and ether, etc. Its solubility reaches the highest in ether.
Keggin type phosphotungstic acid, as a solid acid with excellent catalytic performance, can be used as catalyst in organic catalytic reactions. It can be applied in redox reactions, dehydration/recombination reactions, esterification, Friedel-Crafts alkylation and acylation, asymmetric catalysis, isomerization reaction, the cleavage reaction, as well as open-loop, condensation, addition and etherification.
Producing Method
It can be prepared by ion exchange method, which is developed from the traditional acidification - ether extraction method. This method avoids the use of ether so that the production safety has been improved. But, it has bottleneck in industrial production, such as long production cycle, limited production capacity, and so on.
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