Hydrothermal synthesis of calcium and boron containing MFI-type zeolites by using organic amine as structure directing agent

The hydrothermal syntheses of MFI-type zeolites, MFI and calcium-containing MFI (Ca-MFI), were systematically studied by using simple and inexpensive organic amines, triethylamine (TEA), butylamine (NBA), and 1,6-diaminohexane (DAH), as structure-directing agent (SDA). Boron-containing Ca-MFI ([B]-Ca-MFI) zeolites were also examined by using TEA as SDA. The pure phase of MFI was obtained under appropriate conditions and found that TEA plays an important role as SDA. Resulting Ca-MFI zeolites had hexagonal morphologies, and [B]-Ca-MFI zeolites, of which the morphology was a sticklike prism, had the smaller particle size than Ca-MFI zeolites. The strong acid sites were found over both Ca- and [B]-Ca-MFI zeolites after ion exchange to proton-type form. The incorporated calcium into MFI zeolites by using triethylamine was not leached significantly during the ion exchange compared to the conventional MFI zeolites synthesized by using tetrapropylammonium bromide as SDA. Topological changes from MFI zeolites to TON-type zeolites with NBA and DAH as SDA were observed by changing from static to rotating conditions.