Synthesis, physicochemical properties and hydroisomerization activity of SAPO-11 based catalysts Original Research Article

A series of silicoaluminophosphate (SAPO)-11 molecular sieve samples by using various raw materials and process parameters was prepared. Two of the selected SAPO structure materials were formed in extrudate supports, impregnated with platinum acid solution, thermally treated and tested in hydroisomerization process of so-called “cetane fraction” (mixture of n-C13–n-C20 hydrocarbons). It was found that the preferred parameters of SAPO-11 crystallization are: time, 20 h; temperature, 473 K, with use of n-propylamine as a pore shaping reagent. The obtained SAPO-11 samples were micro-porous materials, micropores consists of ca. 65% of total pore volume and 85% of total specific surface area. Application of Pt catalysts supported on SAPO-11 and alumina binder containing carrier (weight ratio 1:1) enabled hydroisomerization of cetane, n-paraffins fraction, with selectivity of 80–84%. At the low conversion levels the main product of isomerization were mono-branched paraffins while higher process temperature and the increase in conversion favoured obtaining of di- and poly-branched isomers.