3362.     ---------------.  [TEICHNER, S.]  [Kieselguhrs of the Type Utilized as Support for Catalysts.]  Jour. chim. phys., vol. 47, 1950, pp. 229-232; Chem. Abs., vol. 44, 1950, p. 7635.

        Following properties of raw kieselguhr, kieselguhr treated with HCl and HNO₂ and calcined kieselguhr were determined after different thermal treatments:  Loss in weight after etching in Na₂CO₃, density, and specific surface as determined by adsorption of N₂ and CO at -195° and C₄H₁₀ at 0°.  The kieselguhr treated with acids had approximately 50% greater specific surface than the raw kieselguhr.  The specific surface of the calcined kieselguhr was only 11% as great as that of the untreated kieselguhr.  Treatment with 5% Na₂CO₃ reduced slightly the surface area of the raw kieselguhr, but the same treatment decreased by 50% the surface area of the acid-treated kieselguhr.  Presumably the acid treatment caused the formation of siliceous gel, which was soluble in Na₂CO₃.  Discusses significance of the results to the activity of supports for catalysts used in the Fischer-Tropsch process.