| 摘要 |
1,265,890. Aerogels. FRANCE ARMED FORCES MINISTER OF. 15 July, 1969 [15 July, 1968], No. 35673/69. Headings C1A and C1N. An aerogel of a metal oxide e.g. aluminium, titanium or zirconium oxide is made by mixing water with either (a) a solution of a hydrolysable metal alcoholate in a water-immiscible organic medium or (b) a suspension of such an alcoholate in a water-miscible organic medium so as to hydrolyse the alcoholate to a precipitated metal hydroxide, and removing the organic medium and at least the majority of the water by evacuation in an autoclave. An inhomogeneous 2-phase system (not counting precipitated metal oxide) is produced on mixing the water and alcoholate solution or suspension. The water-immiscible solvent may be benzene, and the water immiscible suspending agent may be the alcohol corresponding to the alcoholate group of tho metal compound. The mixing with water may be effected under acid or alkaline conditions by adding acetic acid or ammonia. Examples describe the preparation of zirconium and titanium oxide aerogels from n-butylates, npropylates and isopropylates. |
