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Aqueous Solutions of Mo‐V‐Phosphoric Heteropoly Acids as Bifunctional Catalysts For Preparation of 9,10‐Anthraquinone and its Hydrogenated Derivatives
Author(s) -
Zhizhina Elena G.,
Odyakov Viktor F.
Publication year - 2012
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201200039
Subject(s) - chemistry , bifunctional , anthraquinone , hydroquinone , aqueous solution , catalysis , phosphoric acid , benzoquinone , quinone , inorganic chemistry , organic chemistry
Acid‐catalyzed condensation of 1,3‐butadiene with para ‐quinones and oxidation of resulting adducts can be performed as a one‐pot process in the presence of aqueous solutions of Mo‐V‐phosphoric heteropoly acids (HPA) with the general formula H a P z Mo y V x O b . These solutions have bifunctional catalytic properties; they are both strong Brønsted acids and reversible oxidants. Condensation of hydroquinone, 1,4‐benzoquinone, or 1,4‐naphthoquinone with 1,3‐butadiene in the HPA solutions results in 9,10‐anthraquinone (AQ) in a mixture with tetrahydro‐AQ (THA) and dihydro‐AQ (DHA). In this one‐pot process, which proceeds in the absence of organic solvents, the HPA solution is reduced. A slightly soluble mixture of THA, DHA, and AQ is precipitated and filtered off. The non‐Keggin‐type H 12 P 3 Mo 18 V 7 O 85 solution is the most effective in this process. This solution can be rapidly regenerated by dioxygen or air at temperatures of up to 170 °C and then reused. The prepared THA+DHA+AQ mixture can be used as a catalyst for alkaline delignification of wood. Our homogeneous bifunctional HPA catalyst is very stable and promising for use in similar one‐pot processes.