Hydroxy oxo fluorides as Bi-acidic Catalysts

Depending on the nature of the metals the M-OH units created in a metal fluoride system may either react as a base or as a (Brpnsted) acid. Thus, replacement of F by OH, or vice versa, should result in an alteration of the basicity of M-OH groups, e.g. in MgF2 x(OH)x derivatives as compared to Mg(OH)2 and in the same way of the (Brpnsted) acidity, e.g. in A1F3 x(OH)x phases as compared to Al(OH)3. 

some of the fluoride ions of a metal fluoride can be replaced by hydroxyl and/or oxide groups in the course of its preparation by introducing defined amounts of water at different steps of the synthesis, modifying the properties. 

The most active catalyst h-Mg(OH)o.4Fi,6 was also used in three other Michael addition reactions, i.e. addition of 2-acetylcyclopentanone, 2-acetylcyclohexanone, and 2-methox-ycarbonyl-cyclopentanone to methyl vinyl ketone. These reactions proceeded also with high (75-90%) yields and 100% selectivity [16]. 

Another closely related synthesis route to partly hydroxylated metal fluorides starts from metal alkoxide in alcohol, which is reacted with the stoichiometric amount of hydrogen fluoride dissolved in different amounts of water thus enabling the competition between fluorolysis and hydrolyis, which to some extent is ruled by the HF to H2O ratio and results in partly hydroxylated fluorides. 

Entry Catalyst Number of A.C./m IP/catmolar ratio Time, (min) Conversion of isophytol Yield of tocopherol (%) 

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