Titanium oxide sol and process for producing polyalkylene terephthalate therewith

摘要

An object of the present invention is to provide an environmentally friendly polymerization catalyst of polyalkylene terephthalate which does not use a heavy metal such as antimony. Another object of the present invention is to provide the method of producing polyalkylene terephthalate using the catalyst. The inventive titanium oxide sol for a catalyst for polymerizing a polyalkylene terephthalate is a titanium oxide sol containing an organic solvent as a dispersion medium, wherein the titanium oxide in the sol has a concentration of 0.7 g/L, the sol has a light transmittance of not less than 50%, the light transmittance being measured by setting an optical path length to 1 cm in a wavelength range of 400 to 800 nm, and the amount of hydroxyl groups per 1 g of titanium oxide is not less than 1.8 mmol.