Heating silica gel in inert atmosphere before activation
AssigneePhillips Petroleum Company
InventorDonald R. Witt
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Abstract
A silica hydrogel is contacted with a hydroxy-containing organic compound which is not completely miscible with water but which is sufficiently miscible with water so as to remove water, and thereafter the organic compound is removed by heating in an inert atmosphere prior to activation by heating in air. The heating in the inert atmosphere allows utilizing preferred organic compounds such as C.sub.5 and C.sub.6 alcohols which are desirable from a commercial standpoint because of the easy separation for recycle. In a preferred embodiment, the hydrogel is aged at a pH of 7 to 9 by means of either adding a base or by utilizing a chromium component containing bound nitrogen.
Claims24
A process comprising:
- forming a silica hydrogel;
- aging said hydrogel for a time of at least one hour;
- treating the thus aged hydrogel with a volatile normally liquid saturated aliphatic alcohol having a solubility in water of less than 6 grams per 100 grams of water to convert said hydrogel to a xerogel;
- subjecting the thus formed xerogel to a heat treatment in an inert atmosphere at an elevated temperature;
- and
- activating the thus heat treated xerogel, said xerogel also containing chromium, in an oxygen-containing ambient for a time sufficient to activate same.
Dependencies are inferred from the claim text.