일련의 TiO₂- SiO₂촉매를 TiCl₄와 NaSiO₃혼합용액을 공침전시켜 제조하였으며 이중 일부의 촉매는 1N H_2SO_4로 처리하여 촉매표면을 개질하였다. 개질된 촉매의 촉매활성은 개질 안된 촉매보다 높은 촉매활성을 나타내었으며 cumene dealkylation 반응에서 보다 2 - propanol dehydration 반응에서 더욱 효과가 크게 나타났다. 개질 안된 촉매의 상기 두 반응에 대한 촉매활성은 산의 양과 관계가 있었다. TiO₂- SiO₂촉매는 비교적 많은 양의 약한 산자리와 작은 양의 강한 산자리를 가졌기 때문에 cumene dealkylation 반응에서 보다 2 - propanol dehydration 반응에 더 높은 촉매활성을 나타내었다. 촉매활성에 미치는 H_2SO_4의 개질효과는 TiO₂함량에 비례하였으며 92 - TiO₂- SiO₂/SO_4^2가 2 - propanol dealkylation 반응에 가장 큰 촉매활성의 증가를 나타내었다.

A series of TiO₂- SiO₂catalysts were prepared by coprecipitation from the mixed solution of titanium tetrachloride and sodium silicate. Some of the samples were treated with 1N H_2SO_4 and used as modified catalysts. The catalytic activities of modified catalysts were higher than those of unmodified catalysts, and the effect of modification on the catalytic activity was higher for 2 - propanol dehydration than for cumene dealkylation. The catalytic activity of unmodified catalysts was correlated with their acid amount for the above two reactions. As TiO₂- SiO₂catalysts had relatively large amount of weak acid sites and small amount of strong acid sites, the catalytic activity for 2 - propanol dehydration was higher than that for cumene dealkylation. The effect of modification on catalytic activity increased with increasing TiO₂ content of the catalysts. Actually, 92 - TiO₂- SiO₂/SO_4^2 had the highest increment in catalytic activity and 10 - TiO₂- SiO₂/SO_4^2 had the lowest increment for the 2 - propanol dehydration.