Patent ID: 8747542

Claim:
A method for producing a rutile titanium oxide sol having a particle diameter measured by dynamic light scattering of 5 nm to 100 nm, the method comprising: a process (a): mixing a tin oxalate aqueous solution, a titanium alkoxide, oxalic acid, a quaternary ammonium hydroxide, and water, while adjusting, per mole of titanium atoms, a proportion of tin atoms to be from 0.1 mol to 0.8 mol, a proportion of the oxalic acid to be from 0.01 mol to 5 mol, and a proportion of the quaternary ammonium hydroxide to be from 0.1 mol to 3.5 mol to prepare a titanium-containing aqueous solution having a concentration in terms of TiO 2 of 0.1% by mass to 15% by mass; and a process (b): performing hydrothermal treatment on the titanium-containing aqueous solution produced in the process (a) at 100° C. to 200° C.