Catalytic properties of a heated ammonium-saturated dioctahedral smectite

A series of acid catalysts was prepared by heating of NH4-saturated montmor illonite 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 thu s suitable for testing catalytic activity of modified montmorillonites. Mos t of the prepared catalysts were able to catalyse the test reaction and pro duce diacetate in higher than 50% yields. The most active catalyst was obta ined after heating at 300 degreesC. It was slightly less effective than com mercially available acid-activated K10 catalyst.