Preparation of hierarchical SAPO-11 molecular sieve and its application for n-dodecane isomerization

The isomerization conversion of long chain paraffins for high quality lube oil production plays an important role in the petrochemical industry. The conventional isomerization catalyst, SAPO-11 molecular sieve, exhibits disadvantages for large molecule transfer and multi-branched isomer conversion. To overcome the difficulty of long chain paraffin isomerization, SAPO-11 with hierarchical structure was synthesized by acid modification. With comparison of citric acid modification and hydrochloride acid modification, the hierarchical SAPO-11 was obtained and characterized by nitrogen sorption, XRD, SEM, TEM, and Py-FTIR. The catalytic isomerization activity of prepared hierarchical SAPO-11 was evaluated by n -dodecane isomerization reaction, and the results showed that it had high isomerization conversion and multi-branched isomer selectivity.