Bifunctional solid acid photocatalyst TiO2/AC/SO3H with high acid density for pure green photosynthesis of 2-quinoline carboxamide

Quinoline ramifications possess a wide range of biological activities and potential pharmacological activities. Here, a concept of bifunctional solid acid photocatalyst TiO 2 /AC/SO 3 H with high acid density is firstly purposed for efficiently pure green synthesis of 2-quinoline carboxamide under ultraviolet-visible light irradiation. After sulfonation, the acid density of TiO 2 /AC is markedly larger than that of sole TiO 2 or AC, and the maximum yield of 2-quinoline carboxamide of 39% is obtained when the acid density of catalyst reaches 1.55   mmol/g. The new concept of bifunctional catalysis using solid acid and photocatalyst is potential for industrial application and instructive in green organic synthesis reactions which need radical and acid simultaneously.