Crystalline silicic acid, its salts, and processes for their preparation
Patent 4581213 Issued on April 8, 1986. Estimated Expiration Date: 
January 2, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 2, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod of preparing crystalline zeolite Method of preparing crystalline zeolite Crystalline aluminosilicate and process for its production Patent #: 4481174 InventorApplicationNo. 06/688454 filed on 01/02/1985US Classes:423/325, Oxygen containing423/324, SILICON OR COMPOUND THEREOF423/328.2, Crystalline423/332, Alkali metal containing (Li, Na, K, Rb, or Cs)423/333By precipitating or gelling from silicate solutionExaminersPrimary: Doll, JohnAssistant: Leeds, Jackson Attorney, Agent or FirmInternational ClassesC01B 33/12 (20060101)C01B 33/38 (20060101) C01B 33/00 (20060101) Foreign Application Priority Data1984-01-04 DEAbstractCrystalline sodium silicates having a sheet structure and an ion exchange capacity of 83-130 mmol of Na+ /mol of SiO2 are prepared by a method in which an aqueous reaction mixture which contains sodium silicate, has a molar ratio SiO2 /Na2 O of 3.9:1 to 15:1 and a molar ratio H2 O/(Na2 O+SiO2) of 3:1 to 80:1 and contains 0.01 to 30% by weight, relative to the amount of SiO2 in the reaction mixture employed, of seed crystals of the desired crystalline sodium silicate is prepared, the mixture is heated to temperatures of 160° to 250° C., the reaction is carried out at least until, in the X-ray diffraction pattern of a sample filtered off under suction and dried at 120° C., the ratio of the intensity of the reflection at the interplanar spacing d1 =(20&#b1;2)⋅10-8 cm to the intensity of any reflection present at the interplanar spacing d2 =(15.5&#b1;1.5)⋅10-8 cm is at least 3:1, and the reaction is terminated before the intensity of the reflection at the interplanar spacing d3 =(3.34&#b1;0.04)⋅10-8 cm reaches or exceeds the intensity of the reflection at the interplanar spacing d4 =(3.44&#b1;0.04)⋅10-8 cm. A crystalline silicic acid having a sheet structure and the overall composition H2 Six O2x+1, wherein 15<x<24, and its sodium salt are described.Other References
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