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US 4,300,911 AGranted
Method for preparing crystalline SiO.sub.2 modification
AssigneeBASF SE
InventorsLaszlo Marosi, Joachim Stabenow, Matthias Schwarzmann
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Abstract
A crystalline SiO.sub.2 --modification, which is characterized by an X-ray diffraction diagram having certain diffraction lines, and a process for the preparation of this crystalline SiO.sub.2 --modification by crystallizing reactive amorphous SiO.sub.2 under hydrothermal conditions in the presence of hexamethylenediamine. Sodium ions, phosphate ions and/or sulfate ions may be added for the crystallization.
Claims5
A process for the preparation of a crystalline SiO.sub.2 -modification characterized by an X-ray diffraction diagram which exhibits at least the following diffraction lines:
- ______________________________________ d (A) I ______________________________________ 11.60 36 10.02 15 5.80 11 4.18 100 3.87 79 2.84 16 ______________________________________
- which process comprises heating a mixture of a reactive amorphous SiO.sub.2 in an aqueous solution of hexamethylenediamine at a temperature of from 100.degree. to 200.degree. C. for from 0.5 to 50 days, to effect crystallization of the SiO.sub.2 to said crystalline SiO.sub.2 -modification.
Dependencies are inferred from the claim text.