Synthesis of SAPO-41 from a new reproducible route using H 3PO 3 as the phosphorus source and its application in hydroisomerization of n-decane

Abstract

In the new reproducible route, phosphorous acid (H 3PO 3) or the mixture of H 3PO 3 and phosphoric acid (H 3PO 4) are used as the phosphorus source to synthesize microporous silicoaluminophosohates. It is found that gels containing H 3PO 3 favor the formation of SAPO-41 materials. With only H 3PO 3 as the phosphorus source, pure SAPO-41 phase can be prepared with high crystallinity. When the mixture of H 3PO 3 and H 3PO 4 is used as the phosphorus source, the crystallization of SAPO-41 can be accelerated. Raman and XRD results show that SAPO-41 can be formed after crystallizing for 12 h. The dosage of the template di- n-propylamine (DPA) can be reduced in the mixed phosphorus source system. The SAPO-41 has been used to prepare catalysts for the hydroisomerization of n-decane. High selectivity of isomerization (89.5%) has been observed even at high conversion (88%) over the Pt/SAPO-41.