HIGHLY SELECTIVE MONOETHERIFICATION OF SYMMETRICAL DIOLS CATALYZED BY METALLIC SULFATE SUPPORTED ON SILICA-GEL

Several symmetrical primary and secondary diols from C2 to C-16 have been protected in high selectivity by tetrahydropyranyl ether formation catalysed by metallic sulfates supported on silica gel. This selective etherification is simple and practical. The selectivity of monoether formation depends upon the composition and the volume of solvents. The selectivity can be explained by preferential adsorption of diols to monoethers and the formation of thin liquid films of diols on the surface of catalysts caused by the limited dissolution of the diols in DHP-hexane mixtures.