The novel TUN-type aluminoborosilicate zeolite (denoted as [Al, B]-TUN), which consists of a three-dimensional pore system with 10-ring, has been hydrothermally synthesized for the first time and implied in cracking reaction. The mother gel composition including aluminum, boron, organic structure-directing agent and sodium were intensively studied and optimized. We found for the first time that the incorporation of B together with Al T-sites into the TUN framework led to the control of acidic properties including the number, strength and distribution of acid sites. The n-hexane cracking over different catalysts show that the [Al, B]-TUN zeolites have a longer catalyst duration and a higher P/E ratio (propylene/ethylene selectivity) than [Al]-TUN. Moreover, the comparison between TUN, MFI and *BEA-type zeolites indicates that TUN-type zeolite has a preference for propylene production. The relationship between acidic properties and carking behaviors were discussed and supported by the constraint index (CI) value measurement.
ASJC Scopus subject areas
- 化学 (全般)