Tightening environmental legislation is driving the fine and speciality chemicals industries to consider alternative processes that avoid the use of conventional mineral acids. The use of heterogeneous catalysts in these processes would vastly simplify catalyst removal, minimizing the amount of waste formed. However, diffusion limitation of liquids within porous solids dictates that effective solid acids for liquid-phase reactions require the use of mesoporous materials
Wilson, K., & Clark, J. H. (2000). Solid acids and their use as environmentally friendly catalysts in organic synthesis. Pure and Applied Chemistry, 72(7), 1313-1319. https://doi.org/10.1351/pac200072071313.