Catalytic properties of a heated ammonium-saturated dioctahedral smectite

A series of acid catalysts was prepared by heating of NH4-saturated montmorillonite at 200-600 degreesC for 24 h. Their catalytic activity was tested in acetylation of 3,4,5-trimethoxy benzaldehyde with acetic anhydride. This reaction is sufficiently sensitive to modification of the catalyst and thus suitable for testing catalytic activity of modified montmorillonites. Most of the prepared catalysts were able to catalyse the test reaction and produce diacetate in higher than 50% yields. The most active catalyst was obtained after heating at 300 degreesC. It was slightly less effective than commercially available acid-activated K10 catalyst.