The synthesis of offretite single crystals in the system containing pyrocatechol or F-

Zeolite offretite (OFF), especially large single crystal, is widely used in many fields. But there has been seldom report about the synthesis of large single crystals of offretite. Recently, offretite single crystals have been successfully prepared in the systems containing pyrocatechol and F-. Compared with other methods, zeolite offretite synthesized in these two systems has much better morphology and larger size. Pyrocatechol and F- are effectively used as complex for Si and Al species. Slowly and continuously, the species could be hydrolized to the active species, which favors to build the preliminary structure unite of Si-O-Si or Si-O-Al via condensation reaction. The influences of pyrocatechol, F- and other factors, which affect the morphology of offretite crystals, such as aluminum source, temperature, the ratio of SiO2 to Al2O3, have been studied, and the SEM photographs have been shown. (C) 2001 Elsevier Science B.V. All rights reserved.