PREPARATION OF AN ALUMINUM OXO-HYDROXIDE GEL IN ORGANIC MEDIUM

A new method has been developed to prepare aluminum oxo-hydroxide cont aining spinnable material and gel. Partial hydrolysis of Al(NO3)(3) . 9H(2)O in 1-propanol at 78 degrees C produces a spinnable, viscous mix ture. The role of the propanol in the hydrolysis proved to be to decre ase the polarity of the solvent. In this medium the dissociation of ni tric acid is driven back and it decomposes to nitrous gases resulting in the increase of pH in the solution. The conditions have been optimi zed to obtain the highest hydrolysis degree and to avoid precipitation of basic aluminium nitrate. The resulting optimal temperature is 76-8 0 degrees C, the time needed is at least 15 h in the case of a laborat ory scale preparation. Increasing the ratio of propanol: water and the concentration of Al(III) to the maximum value, leads to the decomposi tion of 54% of the initial amount NO3- ion. By careful drying, the dec omposition continues to about 70% and a solid foam comes into existenc e from the viscous mixture. This foam is able to swell in water, the d egree of swelling in mass is about 10. The drying of swollen gel was e xamined. The spinnable mixture most likely contains polymer chains bui lt up by H-bonds, the foam and the gel probably contain platelets.