Alkoxide Hydrolysis Process:
This process can be classified into two methods depending on the type of Hydrolysis reactions.
In the first process ultra fine Titania powder can be prepared through hydrolysis of Titanium Isopropoxide, Butoxide or Ethoxide at about 25.C. The liquid Titanium Alkoxide solution is pressurized with Nitrogen gas and the entire solution is sprayed into a stirred water path. This process forms a cloudy precipitate of the precursor of Titania.
Since the Titanium Butoxide and Titanium Ethoxide are very viscous in nature they should be diluted with known quantity of the respective alcohols so as to reduce the viscosity. This facilitates the flowability of the solution when it is pressurized.
The formed precursor Titania is washed with water and excess propanol so as to form amorphous precursor Titania. Then it is calcined at about 550.C for 6 to 8 hours to form both the anatase rutile phases. The proportion of anatase and rutile depends on the typr of the starting alkoxide. The particle size of the powder is less than 1 micron and decreases further with the decreasing concentration of the reacting alkoxides.
To be contd…
